]> scripts.mit.edu Git - autoinstalls/wordpress.git/blobdiff - wp-includes/query.php
WordPress 4.4.1
[autoinstalls/wordpress.git] / wp-includes / query.php
index 0f394f0fa1e0ac44f490f3a061420eb355d7f5f0..9460d32450ba9cb0d2addf1105df4413da0f6058 100644 (file)
@@ -2,10 +2,10 @@
 /**
  * WordPress Query API
  *
- * The query API attempts to get which part of WordPress to the user is on. It
- * also provides functionality to getting URL query information.
+ * The query API attempts to get which part of WordPress the user is on. It
+ * also provides functionality for getting URL query information.
  *
- * @link http://codex.wordpress.org/The_Loop More information on The Loop.
+ * @link https://codex.wordpress.org/The_Loop More information on The Loop.
  *
  * @package WordPress
  * @subpackage Query
 /**
  * Retrieve variable in the WP_Query class.
  *
- * @see WP_Query::get()
  * @since 1.5.0
- * @uses $wp_query
+ * @since 3.9.0 The `$default` argument was introduced.
  *
- * @param string $var The variable key to retrieve.
- * @return mixed
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param string $var       The variable key to retrieve.
+ * @param mixed  $default   Optional. Value to return if the query variable is not set. Default empty.
+ * @return mixed Contents of the query variable.
  */
-function get_query_var($var) {
+function get_query_var( $var, $default = '' ) {
        global $wp_query;
-
-       return $wp_query->get($var);
+       return $wp_query->get( $var, $default );
 }
 
-
 /**
- * Retrieve the currently-queried object.  Wrapper for $wp_query->get_queried_object()
+ * Retrieve the currently-queried object.
  *
- * @uses WP_Query::get_queried_object
+ * Wrapper for WP_Query::get_queried_object().
  *
  * @since 3.1.0
  * @access public
  *
- * @return object
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @return object Queried object.
  */
 function get_queried_object() {
        global $wp_query;
@@ -44,14 +46,15 @@ function get_queried_object() {
 }
 
 /**
- * Retrieve ID of the current queried object. Wrapper for $wp_query->get_queried_object_id()
+ * Retrieve ID of the current queried object.
  *
- * @uses WP_Query::get_queried_object_id()
+ * Wrapper for WP_Query::get_queried_object_id().
  *
  * @since 3.1.0
- * @access public
  *
- * @return int
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @return int ID of the queried object.
  */
 function get_queried_object_id() {
        global $wp_query;
@@ -61,18 +64,16 @@ function get_queried_object_id() {
 /**
  * Set query variable.
  *
- * @see WP_Query::set()
  * @since 2.2.0
- * @uses $wp_query
  *
- * @param string $var Query variable key.
- * @param mixed $value
- * @return null
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param string $var   Query variable key.
+ * @param mixed  $value Query variable value.
  */
-function set_query_var($var, $value) {
+function set_query_var( $var, $value ) {
        global $wp_query;
-
-       return $wp_query->set($var, $value);
+       $wp_query->set( $var, $value );
 }
 
 /**
@@ -82,14 +83,14 @@ function set_query_var($var, $value) {
  * once. This must not be used within the WordPress Loop.
  *
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @param string $query
  * @return array List of posts
  */
-function &query_posts($query) {
-       unset($GLOBALS['wp_query']);
-       $GLOBALS['wp_query'] =& new WP_Query();
+function query_posts($query) {
+       $GLOBALS['wp_query'] = new WP_Query();
        return $GLOBALS['wp_query']->query($query);
 }
 
@@ -101,26 +102,28 @@ function &query_posts($query) {
  * wp_query object is not destroyed properly before another is set up.
  *
  * @since 2.3.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query     Global WP_Query instance.
+ * @global WP_Query $wp_the_query Copy of the global WP_Query instance created during wp_reset_query().
  */
 function wp_reset_query() {
-       unset($GLOBALS['wp_query']);
-       $GLOBALS['wp_query'] =& $GLOBALS['wp_the_query'];
+       $GLOBALS['wp_query'] = $GLOBALS['wp_the_query'];
        wp_reset_postdata();
 }
 
 /**
  * After looping through a separate query, this function restores
- * the $post global to the current post in the main query
+ * the $post global to the current post in the main query.
  *
  * @since 3.0.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  */
 function wp_reset_postdata() {
        global $wp_query;
-       if ( !empty($wp_query->post) ) {
-               $GLOBALS['post'] = $wp_query->post;
-               setup_postdata($wp_query->post);
+
+       if ( isset( $wp_query ) ) {
+               $wp_query->reset_postdata();
        }
 }
 
@@ -129,13 +132,13 @@ function wp_reset_postdata() {
  */
 
 /**
- * Is the query for an archive page?
+ * Is the query for an existing archive page?
  *
  * Month, Year, Category, Author, Post Type archive...
  *
- * @see WP_Query::is_archive()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -151,13 +154,13 @@ function is_archive() {
 }
 
 /**
- * Is the query for a post type archive page?
+ * Is the query for an existing post type archive page?
  *
- * @see WP_Query::is_post_type_archive()
  * @since 3.1.0
- * @uses $wp_query
  *
- * @param mixed $post_types Optional. Post type or array of posts types to check against.
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param string|array $post_types Optional. Post type or array of posts types to check against.
  * @return bool
  */
 function is_post_type_archive( $post_types = '' ) {
@@ -172,15 +175,16 @@ function is_post_type_archive( $post_types = '' ) {
 }
 
 /**
- * Is the query for an attachment page?
+ * Is the query for an existing attachment page?
  *
- * @see WP_Query::is_attachment()
  * @since 2.0.0
- * @uses $wp_query
  *
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param int|string|array|object $attachment Attachment ID, title, slug, or array of such.
  * @return bool
  */
-function is_attachment() {
+function is_attachment( $attachment = '' ) {
        global $wp_query;
 
        if ( ! isset( $wp_query ) ) {
@@ -188,18 +192,18 @@ function is_attachment() {
                return false;
        }
 
-       return $wp_query->is_attachment();
+       return $wp_query->is_attachment( $attachment );
 }
 
 /**
- * Is the query for an author archive page?
+ * Is the query for an existing author archive page?
  *
  * If the $author parameter is specified, this function will additionally
  * check if the query is for one of the authors specified.
  *
- * @see WP_Query::is_author()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @param mixed $author Optional. User ID, nickname, nicename, or array of User IDs, nicknames, and nicenames
  * @return bool
@@ -216,14 +220,14 @@ function is_author( $author = '' ) {
 }
 
 /**
- * Is the query for a category archive page?
+ * Is the query for an existing category archive page?
  *
  * If the $category parameter is specified, this function will additionally
  * check if the query is for one of the categories specified.
  *
- * @see WP_Query::is_category()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @param mixed $category Optional. Category ID, name, slug, or array of Category IDs, names, and slugs.
  * @return bool
@@ -240,19 +244,19 @@ function is_category( $category = '' ) {
 }
 
 /**
- * Is the query for a tag archive page?
+ * Is the query for an existing tag archive page?
  *
  * If the $tag parameter is specified, this function will additionally
  * check if the query is for one of the tags specified.
  *
- * @see WP_Query::is_tag()
  * @since 2.3.0
- * @uses $wp_query
  *
- * @param mixed $slug Optional. Tag slug or array of slugs.
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param mixed $tag Optional. Tag ID, name, slug, or array of Tag IDs, names, and slugs.
  * @return bool
  */
-function is_tag( $slug = '' ) {
+function is_tag( $tag = '' ) {
        global $wp_query;
 
        if ( ! isset( $wp_query ) ) {
@@ -260,11 +264,11 @@ function is_tag( $slug = '' ) {
                return false;
        }
 
-       return $wp_query->is_tag( $slug );
+       return $wp_query->is_tag( $tag );
 }
 
 /**
- * Is the query for a taxonomy archive page?
+ * Is the query for an existing taxonomy archive page?
  *
  * If the $taxonomy parameter is specified, this function will additionally
  * check if the query is for that specific $taxonomy.
@@ -273,12 +277,12 @@ function is_tag( $slug = '' ) {
  * this function will additionally check if the query is for one of the terms
  * specified.
  *
- * @see WP_Query::is_tax()
  * @since 2.5.0
- * @uses $wp_query
  *
- * @param mixed $taxonomy Optional. Taxonomy slug or slugs.
- * @param mixed $term Optional. Term ID, name, slug or array of Term IDs, names, and slugs.
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param string|array     $taxonomy Optional. Taxonomy slug or slugs.
+ * @param int|string|array $term     Optional. Term ID, name, slug or array of Term IDs, names, and slugs.
  * @return bool
  */
 function is_tax( $taxonomy = '', $term = '' ) {
@@ -295,9 +299,9 @@ function is_tax( $taxonomy = '', $term = '' ) {
 /**
  * Whether the current URL is within the comments popup window.
  *
- * @see WP_Query::is_comments_popup()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -313,11 +317,11 @@ function is_comments_popup() {
 }
 
 /**
- * Is the query for a date archive?
+ * Is the query for an existing date archive?
  *
- * @see WP_Query::is_date()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -333,11 +337,11 @@ function is_date() {
 }
 
 /**
- * Is the query for a day archive?
+ * Is the query for an existing day archive?
  *
- * @see WP_Query::is_day()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -355,9 +359,9 @@ function is_day() {
 /**
  * Is the query for a feed?
  *
- * @see WP_Query::is_feed()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @param string|array $feeds Optional feed types to check.
  * @return bool
@@ -376,9 +380,9 @@ function is_feed( $feeds = '' ) {
 /**
  * Is the query for a comments feed?
  *
- * @see WP_Query::is_comments_feed()
  * @since 3.0.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -405,10 +409,9 @@ function is_comment_feed() {
  *
  * Otherwise the same as @see is_home()
  *
- * @see WP_Query::is_front_page()
  * @since 2.5.0
- * @uses is_home()
- * @uses get_option()
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool True, if front of site.
  */
@@ -435,9 +438,9 @@ function is_front_page() {
  *
  * @see is_front_page()
  *
- * @see WP_Query::is_home()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool True if blog view homepage.
  */
@@ -453,11 +456,11 @@ function is_home() {
 }
 
 /**
- * Is the query for a month archive?
+ * Is the query for an existing month archive?
  *
- * @see WP_Query::is_month()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -473,7 +476,7 @@ function is_month() {
 }
 
 /**
- * Is the query for a single page?
+ * Is the query for an existing single page?
  *
  * If the $page parameter is specified, this function will additionally
  * check if the query is for one of the pages specified.
@@ -481,12 +484,12 @@ function is_month() {
  * @see is_single()
  * @see is_singular()
  *
- * @see WP_Query::is_page()
  * @since 1.5.0
- * @uses $wp_query
  *
- * @param mixed $page Page ID, title, slug, or array of such.
- * @return bool
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param int|string|array $page Optional. Page ID, title, slug, or array of such. Default empty.
+ * @return bool Whether the query is for an existing single page.
  */
 function is_page( $page = '' ) {
        global $wp_query;
@@ -502,9 +505,9 @@ function is_page( $page = '' ) {
 /**
  * Is the query for paged result and not for the first page?
  *
- * @see WP_Query::is_paged()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -522,9 +525,9 @@ function is_paged() {
 /**
  * Is the query for a post or page preview?
  *
- * @see WP_Query::is_preview()
  * @since 2.0.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -542,9 +545,9 @@ function is_preview() {
 /**
  * Is the query for the robots file?
  *
- * @see WP_Query::is_robots()
  * @since 2.1.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -562,9 +565,9 @@ function is_robots() {
 /**
  * Is the query for a search?
  *
- * @see WP_Query::is_search()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -580,7 +583,7 @@ function is_search() {
 }
 
 /**
- * Is the query for a single post?
+ * Is the query for an existing single post?
  *
  * Works for any post type, except attachments and pages
  *
@@ -590,12 +593,12 @@ function is_search() {
  * @see is_page()
  * @see is_singular()
  *
- * @see WP_Query::is_single()
  * @since 1.5.0
- * @uses $wp_query
  *
- * @param mixed $post Post ID, title, slug, or array of such.
- * @return bool
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param int|string|array $post Optional. Post ID, title, slug, or array of such. Default empty.
+ * @return bool Whether the query is for an existing single post.
  */
 function is_single( $post = '' ) {
        global $wp_query;
@@ -609,7 +612,7 @@ function is_single( $post = '' ) {
 }
 
 /**
- * Is the query for a single post of any post type (post, attachment, page, ... )?
+ * Is the query for an existing single post of any post type (post, attachment, page, ... )?
  *
  * If the $post_types parameter is specified, this function will additionally
  * check if the query is for one of the Posts Types specified.
@@ -617,12 +620,12 @@ function is_single( $post = '' ) {
  * @see is_page()
  * @see is_single()
  *
- * @see WP_Query::is_singular()
  * @since 1.5.0
- * @uses $wp_query
  *
- * @param mixed $post_types Optional. Post Type or array of Post Types
- * @return bool
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @param string|array $post_types Optional. Post type or array of post types. Default empty.
+ * @return bool Whether the query is for an existing single post of any of the given post types.
  */
 function is_singular( $post_types = '' ) {
        global $wp_query;
@@ -638,9 +641,9 @@ function is_singular( $post_types = '' ) {
 /**
  * Is the query for a specific time?
  *
- * @see WP_Query::is_time()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -658,9 +661,9 @@ function is_time() {
 /**
  * Is the query for a trackback endpoint call?
  *
- * @see WP_Query::is_trackback()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -676,11 +679,11 @@ function is_trackback() {
 }
 
 /**
- * Is the query for a specific year?
+ * Is the query for an existing year archive?
  *
- * @see WP_Query::is_year()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -698,9 +701,9 @@ function is_year() {
 /**
  * Is the query a 404 (returns no results)?
  *
- * @see WP_Query::is_404()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -715,22 +718,67 @@ function is_404() {
        return $wp_query->is_404();
 }
 
+/**
+ * Is the query for an embedded post?
+ *
+ * @since 4.4.0
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @return bool Whether we're in an embedded post or not.
+ */
+function is_embed() {
+       global $wp_query;
+
+       if ( ! isset( $wp_query ) ) {
+               _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1' );
+               return false;
+       }
+
+       return $wp_query->is_embed();
+}
+
+/**
+ * Is the query the main query?
+ *
+ * @since 3.3.0
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
+ *
+ * @return bool
+ */
+function is_main_query() {
+       if ( 'pre_get_posts' === current_filter() ) {
+               $message = sprintf(
+                       /* translators: 1: pre_get_posts 2: WP_Query->is_main_query() 3: is_main_query() 4: link to codex is_main_query() page. */
+                       __( 'In %1$s, use the %2$s method, not the %3$s function. See %4$s.' ),
+                       '<code>pre_get_posts</code>',
+                       '<code>WP_Query->is_main_query()</code>',
+                       '<code>is_main_query()</code>',
+                       __( 'https://codex.wordpress.org/Function_Reference/is_main_query' )
+               );
+               _doing_it_wrong( __FUNCTION__, $message, '3.7' );
+       }
+
+       global $wp_query;
+       return $wp_query->is_main_query();
+}
+
 /*
- * The Loop.  Post loop control.
+ * The Loop. Post loop control.
  */
 
 /**
  * Whether current WordPress query has results to loop over.
  *
- * @see WP_Query::have_posts()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
 function have_posts() {
        global $wp_query;
-
        return $wp_query->have_posts();
 }
 
@@ -738,41 +786,37 @@ function have_posts() {
  * Whether the caller is in the Loop.
  *
  * @since 2.0.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool True if caller is within loop, false if loop hasn't started or ended.
  */
 function in_the_loop() {
        global $wp_query;
-
        return $wp_query->in_the_loop;
 }
 
 /**
  * Rewind the loop posts.
  *
- * @see WP_Query::rewind_posts()
  * @since 1.5.0
- * @uses $wp_query
  *
- * @return null
+ * @global WP_Query $wp_query Global WP_Query instance.
  */
 function rewind_posts() {
        global $wp_query;
-
-       return $wp_query->rewind_posts();
+       $wp_query->rewind_posts();
 }
 
 /**
  * Iterate the post index in the loop.
  *
- * @see WP_Query::the_post()
  * @since 1.5.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  */
 function the_post() {
        global $wp_query;
-
        $wp_query->the_post();
 }
 
@@ -783,9 +827,9 @@ function the_post() {
 /**
  * Whether there are comments to loop over.
  *
- * @see WP_Query::have_comments()
  * @since 2.2.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return bool
  */
@@ -797,9 +841,9 @@ function have_comments() {
 /**
  * Iterate comment index in the comment loop.
  *
- * @see WP_Query::the_comment()
  * @since 2.2.0
- * @uses $wp_query
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
  * @return object
  */
@@ -815,7 +859,7 @@ function the_comment() {
 /**
  * The WordPress Query class.
  *
- * @link http://codex.wordpress.org/Function_Reference/WP_Query Codex page.
+ * @link https://codex.wordpress.org/Function_Reference/WP_Query Codex page.
  *
  * @since 1.5.0
  */
@@ -828,7 +872,7 @@ class WP_Query {
         * @access public
         * @var array
         */
-       var $query;
+       public $query;
 
        /**
         * Query vars, after parsing
@@ -837,7 +881,7 @@ class WP_Query {
         * @access public
         * @var array
         */
-       var $query_vars = array();
+       public $query_vars = array();
 
        /**
         * Taxonomy query, as passed to get_tax_sql()
@@ -846,7 +890,25 @@ class WP_Query {
         * @access public
         * @var object WP_Tax_Query
         */
-       var $tax_query;
+       public $tax_query;
+
+       /**
+        * Metadata query container
+        *
+        * @since 3.2.0
+        * @access public
+        * @var object WP_Meta_Query
+        */
+       public $meta_query = false;
+
+       /**
+        * Date query container
+        *
+        * @since 3.7.0
+        * @access public
+        * @var object WP_Date_Query
+        */
+       public $date_query = false;
 
        /**
         * Holds the data for a single object that is queried.
@@ -857,7 +919,7 @@ class WP_Query {
         * @access public
         * @var object|array
         */
-       var $queried_object;
+       public $queried_object;
 
        /**
         * The ID of the queried object.
@@ -866,7 +928,7 @@ class WP_Query {
         * @access public
         * @var int
         */
-       var $queried_object_id;
+       public $queried_object_id;
 
        /**
         * Get post database query.
@@ -875,7 +937,7 @@ class WP_Query {
         * @access public
         * @var string
         */
-       var $request;
+       public $request;
 
        /**
         * List of posts.
@@ -884,7 +946,7 @@ class WP_Query {
         * @access public
         * @var array
         */
-       var $posts;
+       public $posts;
 
        /**
         * The amount of posts for the current query.
@@ -893,7 +955,7 @@ class WP_Query {
         * @access public
         * @var int
         */
-       var $post_count = 0;
+       public $post_count = 0;
 
        /**
         * Index of the current item in the loop.
@@ -902,7 +964,7 @@ class WP_Query {
         * @access public
         * @var int
         */
-       var $current_post = -1;
+       public $current_post = -1;
 
        /**
         * Whether the loop has started and the caller is in the loop.
@@ -911,16 +973,16 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $in_the_loop = false;
+       public $in_the_loop = false;
 
        /**
-        * The current post ID.
+        * The current post.
         *
         * @since 1.5.0
         * @access public
-        * @var object
+        * @var WP_Post
         */
-       var $post;
+       public $post;
 
        /**
         * The list of comments for current post.
@@ -929,7 +991,7 @@ class WP_Query {
         * @access public
         * @var array
         */
-       var $comments;
+       public $comments;
 
        /**
         * The amount of comments for the posts.
@@ -938,7 +1000,7 @@ class WP_Query {
         * @access public
         * @var int
         */
-       var $comment_count = 0;
+       public $comment_count = 0;
 
        /**
         * The index of the comment in the comment loop.
@@ -947,7 +1009,7 @@ class WP_Query {
         * @access public
         * @var int
         */
-       var $current_comment = -1;
+       public $current_comment = -1;
 
        /**
         * Current comment ID.
@@ -956,16 +1018,18 @@ class WP_Query {
         * @access public
         * @var int
         */
-       var $comment;
+       public $comment;
 
        /**
-        * Amount of posts if limit clause was not used.
+        * The amount of found posts for the current query.
+        *
+        * If limit clause was not used, equals $post_count.
         *
         * @since 2.1.0
         * @access public
         * @var int
         */
-       var $found_posts = 0;
+       public $found_posts = 0;
 
        /**
         * The amount of pages.
@@ -974,7 +1038,7 @@ class WP_Query {
         * @access public
         * @var int
         */
-       var $max_num_pages = 0;
+       public $max_num_pages = 0;
 
        /**
         * The amount of comment pages.
@@ -983,7 +1047,7 @@ class WP_Query {
         * @access public
         * @var int
         */
-       var $max_num_comment_pages = 0;
+       public $max_num_comment_pages = 0;
 
        /**
         * Set if query is single post.
@@ -992,7 +1056,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_single = false;
+       public $is_single = false;
 
        /**
         * Set if query is preview of blog.
@@ -1001,7 +1065,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_preview = false;
+       public $is_preview = false;
 
        /**
         * Set if query returns a page.
@@ -1010,7 +1074,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_page = false;
+       public $is_page = false;
 
        /**
         * Set if query is an archive list.
@@ -1019,7 +1083,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_archive = false;
+       public $is_archive = false;
 
        /**
         * Set if query is part of a date.
@@ -1028,7 +1092,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_date = false;
+       public $is_date = false;
 
        /**
         * Set if query contains a year.
@@ -1037,7 +1101,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_year = false;
+       public $is_year = false;
 
        /**
         * Set if query contains a month.
@@ -1046,7 +1110,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_month = false;
+       public $is_month = false;
 
        /**
         * Set if query contains a day.
@@ -1055,7 +1119,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_day = false;
+       public $is_day = false;
 
        /**
         * Set if query contains time.
@@ -1064,7 +1128,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_time = false;
+       public $is_time = false;
 
        /**
         * Set if query contains an author.
@@ -1073,7 +1137,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_author = false;
+       public $is_author = false;
 
        /**
         * Set if query contains category.
@@ -1082,7 +1146,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_category = false;
+       public $is_category = false;
 
        /**
         * Set if query contains tag.
@@ -1091,7 +1155,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_tag = false;
+       public $is_tag = false;
 
        /**
         * Set if query contains taxonomy.
@@ -1100,7 +1164,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_tax = false;
+       public $is_tax = false;
 
        /**
         * Set if query was part of a search result.
@@ -1109,7 +1173,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_search = false;
+       public $is_search = false;
 
        /**
         * Set if query is feed display.
@@ -1118,7 +1182,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_feed = false;
+       public $is_feed = false;
 
        /**
         * Set if query is comment feed display.
@@ -1127,7 +1191,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_comment_feed = false;
+       public $is_comment_feed = false;
 
        /**
         * Set if query is trackback.
@@ -1136,7 +1200,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_trackback = false;
+       public $is_trackback = false;
 
        /**
         * Set if query is blog homepage.
@@ -1145,7 +1209,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_home = false;
+       public $is_home = false;
 
        /**
         * Set if query couldn't found anything.
@@ -1154,7 +1218,16 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_404 = false;
+       public $is_404 = false;
+
+       /**
+        * Set if query is embed.
+        *
+        * @since 4.4.0
+        * @access public
+        * @var bool
+        */
+       public $is_embed = false;
 
        /**
         * Set if query is within comments popup window.
@@ -1163,7 +1236,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_comments_popup = false;
+       public $is_comments_popup = false;
 
        /**
         * Set if query is paged
@@ -1172,7 +1245,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_paged = false;
+       public $is_paged = false;
 
        /**
         * Set if query is part of administration page.
@@ -1181,7 +1254,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_admin = false;
+       public $is_admin = false;
 
        /**
         * Set if query is an attachment.
@@ -1190,7 +1263,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_attachment = false;
+       public $is_attachment = false;
 
        /**
         * Set if is single, is a page, or is an attachment.
@@ -1199,7 +1272,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_singular = false;
+       public $is_singular = false;
 
        /**
         * Set if query is for robots.
@@ -1208,7 +1281,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_robots = false;
+       public $is_robots = false;
 
        /**
         * Set if query contains posts.
@@ -1219,7 +1292,7 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_posts_page = false;
+       public $is_posts_page = false;
 
        /**
         * Set if query is for a post type archive.
@@ -1228,16 +1301,65 @@ class WP_Query {
         * @access public
         * @var bool
         */
-       var $is_post_type_archive = false;
+       public $is_post_type_archive = false;
 
        /**
-        * Whether the tax query has been parsed once.
+        * Stores the ->query_vars state like md5(serialize( $this->query_vars ) ) so we know
+        * whether we have to re-parse because something has changed
         *
         * @since 3.1.0
         * @access private
+        * @var bool|string
+        */
+       private $query_vars_hash = false;
+
+       /**
+        * Whether query vars have changed since the initial parse_query() call. Used to catch modifications to query vars made
+        * via pre_get_posts hooks.
+        *
+        * @since 3.1.1
+        * @access private
+        */
+       private $query_vars_changed = true;
+
+       /**
+        * Set if post thumbnails are cached
+        *
+        * @since 3.2.0
+        * @access public
+        * @var bool
+        */
+        public $thumbnails_cached = false;
+
+       /**
+        * Whether the term meta cache for matched posts has been primed.
+        *
+        * @since 4.4.0
+        * @access protected
+        * @var bool
+        */
+       public $updated_term_meta_cache = false;
+
+       /**
+        * Whether the comment meta cache for matched posts has been primed.
+        *
+        * @since 4.4.0
+        * @access protected
         * @var bool
         */
-       var $parsed_tax_query = false;
+       public $updated_comment_meta_cache = false;
+
+       /**
+        * Cached list of search stopwords.
+        *
+        * @since 3.7.0
+        * @var array
+        */
+       private $stopwords;
+
+       private $compat_fields = array( 'query_vars_hash', 'query_vars_changed' );
+
+       private $compat_methods = array( 'init_query_flags', 'parse_tax_query' );
 
        /**
         * Resets query flags to false.
@@ -1247,7 +1369,7 @@ class WP_Query {
         * @since 2.0.0
         * @access private
         */
-       function init_query_flags() {
+       private function init_query_flags() {
                $this->is_single = false;
                $this->is_preview = false;
                $this->is_page = false;
@@ -1283,7 +1405,7 @@ class WP_Query {
         * @since 1.5.0
         * @access public
         */
-       function init() {
+       public function init() {
                unset($this->posts);
                unset($this->query);
                $this->query_vars = array();
@@ -1311,7 +1433,7 @@ class WP_Query {
         * @since 1.5.0
         * @access public
         */
-       function parse_query_vars() {
+       public function parse_query_vars() {
                $this->parse_query();
        }
 
@@ -1324,7 +1446,7 @@ class WP_Query {
         * @param array $array Defined query variables.
         * @return array Complete query variables with undefined ones filled in empty.
         */
-       function fill_query_vars($array) {
+       public function fill_query_vars($array) {
                $keys = array(
                        'error'
                        , 'm'
@@ -1349,6 +1471,7 @@ class WP_Query {
                        , 'tag'
                        , 'cat'
                        , 'tag_id'
+                       , 'author'
                        , 'author_name'
                        , 'feed'
                        , 'tb'
@@ -1359,7 +1482,9 @@ class WP_Query {
                        , 'preview'
                        , 's'
                        , 'sentence'
+                       , 'title'
                        , 'fields'
+                       , 'menu_order'
                );
 
                foreach ( $keys as $key ) {
@@ -1367,8 +1492,9 @@ class WP_Query {
                                $array[$key] = '';
                }
 
-               $array_keys = array('category__in', 'category__not_in', 'category__and', 'post__in', 'post__not_in',
-                       'tag__in', 'tag__not_in', 'tag__and', 'tag_slug__in', 'tag_slug__and');
+               $array_keys = array( 'category__in', 'category__not_in', 'category__and', 'post__in', 'post__not_in', 'post_name__in',
+                       'tag__in', 'tag__not_in', 'tag__and', 'tag_slug__in', 'tag_slug__and', 'post_parent__in', 'post_parent__not_in',
+                       'author__in', 'author__not_in' );
 
                foreach ( $array_keys as $key ) {
                        if ( !isset($array[$key]) )
@@ -1381,11 +1507,111 @@ class WP_Query {
         * Parse a query string and set query type booleans.
         *
         * @since 1.5.0
+        * @since 4.2.0 Introduced the ability to order by specific clauses of a `$meta_query`, by passing the clause's
+        *              array key to `$orderby`.
+        * @since 4.4.0 Introduced `$post_name__in` and `$title` parameters. `$s` was updated to support excluded
+        *              search terms, by prepending a hyphen.
         * @access public
         *
-        * @param string|array $query Optional query.
+        * @param string|array $query {
+        *     Optional. Array or string of Query parameters.
+        *
+        *     @type int          $attachment_id           Attachment post ID. Used for 'attachment' post_type.
+        *     @type int|string   $author                  Author ID, or comma-separated list of IDs.
+        *     @type string       $author_name             User 'user_nicename'.
+        *     @type array        $author__in              An array of author IDs to query from.
+        *     @type array        $author__not_in          An array of author IDs not to query from.
+        *     @type bool         $cache_results           Whether to cache post information. Default true.
+        *     @type int|string   $cat                     Category ID or comma-separated list of IDs (this or any children).
+        *     @type array        $category__and           An array of category IDs (AND in).
+        *     @type array        $category__in            An array of category IDs (OR in, no children).
+        *     @type array        $category__not_in        An array of category IDs (NOT in).
+        *     @type string       $category_name           Use category slug (not name, this or any children).
+        *     @type int          $comments_per_page       The number of comments to return per page.
+        *                                                 Default 'comments_per_page' option.
+        *     @type int|string   $comments_popup          Whether the query is within the comments popup. Default empty.
+        *     @type array        $date_query              An associative array of WP_Date_Query arguments.
+        *                                                 {@see WP_Date_Query::__construct()}
+        *     @type int          $day                     Day of the month. Default empty. Accepts numbers 1-31.
+        *     @type bool         $exact                   Whether to search by exact keyword. Default false.
+        *     @type string|array $fields                  Which fields to return. Single field or all fields (string),
+        *                                                 or array of fields. 'id=>parent' uses 'id' and 'post_parent'.
+        *                                                 Default all fields. Accepts 'ids', 'id=>parent'.
+        *     @type int          $hour                    Hour of the day. Default empty. Accepts numbers 0-23.
+        *     @type int|bool     $ignore_sticky_posts     Whether to ignore sticky posts or not. Setting this to false
+        *                                                 excludes stickies from 'post__in'. Accepts 1|true, 0|false.
+        *                                                 Default 0|false.
+        *     @type int          $m                       Combination YearMonth. Accepts any four-digit year and month
+        *                                                 numbers 1-12. Default empty.
+        *     @type string       $meta_compare            Comparison operator to test the 'meta_value'.
+        *     @type string       $meta_key                Custom field key.
+        *     @type array        $meta_query              An associative array of WP_Meta_Query arguments.
+        *                                                 {@see WP_Meta_Query->queries}
+        *     @type string       $meta_value              Custom field value.
+        *     @type int          $meta_value_num          Custom field value number.
+        *     @type int          $menu_order              The menu order of the posts.
+        *     @type int          $monthnum                The two-digit month. Default empty. Accepts numbers 1-12.
+        *     @type string       $name                    Post slug.
+        *     @type bool         $nopaging                Show all posts (true) or paginate (false). Default false.
+        *     @type bool         $no_found_rows           Whether to skip counting the total rows found. Enabling can improve
+        *                                                 performance. Default false.
+        *     @type int          $offset                  The number of posts to offset before retrieval.
+        *     @type string       $order                   Designates ascending or descending order of posts. Default 'DESC'.
+        *                                                 Accepts 'ASC', 'DESC'.
+        *     @type string|array $orderby                 Sort retrieved posts by parameter. One or more options may be
+        *                                                 passed. To use 'meta_value', or 'meta_value_num',
+        *                                                 'meta_key=keyname' must be also be defined. To sort by a
+        *                                                 specific `$meta_query` clause, use that clause's array key.
+        *                                                 Default 'date'. Accepts 'none', 'name', 'author', 'date',
+        *                                                 'title', 'modified', 'menu_order', 'parent', 'ID', 'rand',
+        *                                                 'comment_count', 'meta_value', 'meta_value_num', 'post__in',
+        *                                                 and the array keys of `$meta_query`.
+        *     @type int          $p                       Post ID.
+        *     @type int          $page                    Show the number of posts that would show up on page X of a
+        *                                                 static front page.
+        *     @type int          $paged                   The number of the current page.
+        *     @type int          $page_id                 Page ID.
+        *     @type string       $pagename                Page slug.
+        *     @type string       $perm                    Show posts if user has the appropriate capability.
+        *     @type array        $post__in                An array of post IDs to retrieve, sticky posts will be included
+        *     @type string       $post_mime_type          The mime type of the post. Used for 'attachment' post_type.
+        *     @type array        $post__not_in            An array of post IDs not to retrieve. Note: a string of comma-
+        *                                                 separated IDs will NOT work.
+        *     @type int          $post_parent             Page ID to retrieve child pages for. Use 0 to only retrieve
+        *                                                 top-level pages.
+        *     @type array        $post_parent__in         An array containing parent page IDs to query child pages from.
+        *     @type array        $post_parent__not_in     An array containing parent page IDs not to query child pages from.
+        *     @type string|array $post_type               A post type slug (string) or array of post type slugs.
+        *                                                 Default 'any' if using 'tax_query'.
+        *     @type string|array $post_status             A post status (string) or array of post statuses.
+        *     @type int          $posts_per_page          The number of posts to query for. Use -1 to request all posts.
+        *     @type int          $posts_per_archive_page  The number of posts to query for by archive page. Overrides
+        *                                                 'posts_per_page' when is_archive(), or is_search() are true.
+        *     @type array        $post_name__in           An array of post slugs that results must match.
+        *     @type string       $s                       Search keyword(s). Prepending a term with a hyphen will
+        *                                                 exclude posts matching that term. Eg, 'pillow -sofa' will
+        *                                                 return posts containing 'pillow' but not 'sofa'.
+        *     @type int          $second                  Second of the minute. Default empty. Accepts numbers 0-60.
+        *     @type bool         $sentence                Whether to search by phrase. Default false.
+        *     @type bool         $suppress_filters        Whether to suppress filters. Default false.
+        *     @type string       $tag                     Tag slug. Comma-separated (either), Plus-separated (all).
+        *     @type array        $tag__and                An array of tag ids (AND in).
+        *     @type array        $tag__in                 An array of tag ids (OR in).
+        *     @type array        $tag__not_in             An array of tag ids (NOT in).
+        *     @type int          $tag_id                  Tag id or comma-separated list of IDs.
+        *     @type array        $tag_slug__and           An array of tag slugs (AND in).
+        *     @type array        $tag_slug__in            An array of tag slugs (OR in). unless 'ignore_sticky_posts' is
+        *                                                 true. Note: a string of comma-separated IDs will NOT work.
+        *     @type array        $tax_query               An associative array of WP_Tax_Query arguments.
+        *                                                 {@see WP_Tax_Query->queries}
+        *     @type string       $title                   Post title.
+        *     @type bool         $update_post_meta_cache  Whether to update the post meta cache. Default true.
+        *     @type bool         $update_post_term_cache  Whether to update the post term cache. Default true.
+        *     @type int          $w                       The week number of the year. Default empty. Accepts numbers 0-53.
+        *     @type int          $year                    The four-digit year. Default empty. Accepts any four-digit year.
+        * }
         */
-       function parse_query( $query =  '' ) {
+       public function parse_query( $query =  '' ) {
                if ( ! empty( $query ) ) {
                        $this->init();
                        $this->query = $this->query_vars = wp_parse_args( $query );
@@ -1395,6 +1621,7 @@ class WP_Query {
 
                $this->query_vars = $this->fill_query_vars($this->query_vars);
                $qv = &$this->query_vars;
+               $this->query_vars_changed = true;
 
                if ( ! empty($qv['robots']) )
                        $this->is_robots = true;
@@ -1405,16 +1632,24 @@ class WP_Query {
                $qv['monthnum'] = absint($qv['monthnum']);
                $qv['day'] = absint($qv['day']);
                $qv['w'] = absint($qv['w']);
-               $qv['m'] = absint($qv['m']);
+               $qv['m'] = preg_replace( '|[^0-9]|', '', $qv['m'] );
                $qv['paged'] = absint($qv['paged']);
                $qv['cat'] = preg_replace( '|[^0-9,-]|', '', $qv['cat'] ); // comma separated list of positive or negative integers
+               $qv['author'] = preg_replace( '|[^0-9,-]|', '', $qv['author'] ); // comma separated list of positive or negative integers
                $qv['pagename'] = trim( $qv['pagename'] );
                $qv['name'] = trim( $qv['name'] );
+               $qv['title'] = trim( $qv['title'] );
                if ( '' !== $qv['hour'] ) $qv['hour'] = absint($qv['hour']);
                if ( '' !== $qv['minute'] ) $qv['minute'] = absint($qv['minute']);
                if ( '' !== $qv['second'] ) $qv['second'] = absint($qv['second']);
+               if ( '' !== $qv['menu_order'] ) $qv['menu_order'] = absint($qv['menu_order']);
+
+               // Fairly insane upper bound for search string lengths.
+               if ( ! is_scalar( $qv['s'] ) || ( ! empty( $qv['s'] ) && strlen( $qv['s'] ) > 1600 ) ) {
+                       $qv['s'] = '';
+               }
 
-               // Compat.  Map subpost to attachment.
+               // Compat. Map subpost to attachment.
                if ( '' != $qv['subpost'] )
                        $qv['attachment'] = $qv['subpost'];
                if ( '' != $qv['subpost_id'] )
@@ -1437,9 +1672,9 @@ class WP_Query {
                        $this->is_page = true;
                        $this->is_single = false;
                } else {
-               // Look for archive queries.  Dates, categories, authors, search, post type archives.
+                       // Look for archive queries. Dates, categories, authors, search, post type archives.
 
-                       if ( !empty($qv['s']) ) {
+                       if ( isset( $this->query['s'] ) ) {
                                $this->is_search = true;
                        }
 
@@ -1460,15 +1695,24 @@ class WP_Query {
 
                        if ( $qv['day'] ) {
                                if ( ! $this->is_date ) {
-                                       $this->is_day = true;
-                                       $this->is_date = true;
+                                       $date = sprintf( '%04d-%02d-%02d', $qv['year'], $qv['monthnum'], $qv['day'] );
+                                       if ( $qv['monthnum'] && $qv['year'] && ! wp_checkdate( $qv['monthnum'], $qv['day'], $qv['year'], $date ) ) {
+                                               $qv['error'] = '404';
+                                       } else {
+                                               $this->is_day = true;
+                                               $this->is_date = true;
+                                       }
                                }
                        }
 
                        if ( $qv['monthnum'] ) {
                                if ( ! $this->is_date ) {
-                                       $this->is_month = true;
-                                       $this->is_date = true;
+                                       if ( 12 < $qv['monthnum'] ) {
+                                               $qv['error'] = '404';
+                                       } else {
+                                               $this->is_month = true;
+                                               $this->is_date = true;
+                                       }
                                }
                        }
 
@@ -1483,9 +1727,9 @@ class WP_Query {
                                $this->is_date = true;
                                if ( strlen($qv['m']) > 9 ) {
                                        $this->is_time = true;
-                               } else if ( strlen($qv['m']) > 7 ) {
+                               } elseif ( strlen( $qv['m'] ) > 7 ) {
                                        $this->is_day = true;
-                               } else if ( strlen($qv['m']) > 5 ) {
+                               } elseif ( strlen( $qv['m'] ) > 5 ) {
                                        $this->is_month = true;
                                } else {
                                        $this->is_year = true;
@@ -1496,11 +1740,15 @@ class WP_Query {
                                $this->is_date = true;
                        }
 
-                       $this->parsed_tax_query = false;
+                       $this->query_vars_hash = false;
                        $this->parse_tax_query( $qv );
 
                        foreach ( $this->tax_query->queries as $tax_query ) {
-                               if ( 'IN' == $tax_query['operator'] ) {
+                               if ( ! is_array( $tax_query ) ) {
+                                       continue;
+                               }
+
+                               if ( isset( $tax_query['operator'] ) && 'NOT IN' != $tax_query['operator'] ) {
                                        switch ( $tax_query['taxonomy'] ) {
                                                case 'category':
                                                        $this->is_category = true;
@@ -1515,8 +1763,6 @@ class WP_Query {
                        }
                        unset( $tax_query );
 
-                       _parse_meta_query( $qv );
-
                        if ( empty($qv['author']) || ($qv['author'] == '0') ) {
                                $this->is_author = false;
                        } else {
@@ -1565,7 +1811,7 @@ class WP_Query {
                if ( $this->is_feed && ( !empty($qv['withcomments']) || ( empty($qv['withoutcomments']) && $this->is_singular ) ) )
                        $this->is_comment_feed = true;
 
-               if ( !( $this->is_singular || $this->is_archive || $this->is_search || $this->is_feed || $this->is_trackback || $this->is_404 || $this->is_admin || $this->is_comments_popup || $this->is_robots ) )
+               if ( !( $this->is_singular || $this->is_archive || $this->is_search || $this->is_feed || ( defined( 'REST_REQUEST' ) && REST_REQUEST ) || $this->is_trackback || $this->is_404 || $this->is_admin || $this->is_comments_popup || $this->is_robots ) )
                        $this->is_home = true;
 
                // Correct is_* for page_on_front and page_for_posts
@@ -1587,11 +1833,25 @@ class WP_Query {
                }
 
                if ( '' != $qv['pagename'] ) {
-                       $this->queried_object =& get_page_by_path($qv['pagename']);
-                       if ( !empty($this->queried_object) )
+                       $this->queried_object = get_page_by_path( $qv['pagename'] );
+
+                       if ( $this->queried_object && 'attachment' == $this->queried_object->post_type ) {
+                               if ( preg_match( "/^[^%]*%(?:postname)%/", get_option( 'permalink_structure' ) ) ) {
+                                       // See if we also have a post with the same slug
+                                       $post = get_page_by_path( $qv['pagename'], OBJECT, 'post' );
+                                       if ( $post ) {
+                                               $this->queried_object = $post;
+                                               $this->is_page = false;
+                                               $this->is_single = true;
+                                       }
+                               }
+                       }
+
+                       if ( ! empty( $this->queried_object ) ) {
                                $this->queried_object_id = (int) $this->queried_object->ID;
-                       else
-                               unset($this->queried_object);
+                       } else {
+                               unset( $this->queried_object );
+                       }
 
                        if  ( 'page' == get_option('show_on_front') && isset($this->queried_object_id) && $this->queried_object_id == get_option('page_for_posts') ) {
                                $this->is_page = false;
@@ -1615,8 +1875,12 @@ class WP_Query {
                                $qv['post_type'] = sanitize_key($qv['post_type']);
                }
 
-               if ( !empty($qv['post_status']) )
-                       $qv['post_status'] = preg_replace('|[^a-z0-9_,-]|', '', $qv['post_status']);
+               if ( ! empty( $qv['post_status'] ) ) {
+                       if ( is_array( $qv['post_status'] ) )
+                               $qv['post_status'] = array_map('sanitize_key', $qv['post_status']);
+                       else
+                               $qv['post_status'] = preg_replace('|[^a-z0-9_,-]|', '', $qv['post_status']);
+               }
 
                if ( $this->is_posts_page && ( ! isset($qv['withcomments']) || ! $qv['withcomments'] ) )
                        $this->is_comment_feed = false;
@@ -1627,18 +1891,32 @@ class WP_Query {
                if ( '404' == $qv['error'] )
                        $this->set_404();
 
-               do_action_ref_array('parse_query', array(&$this));
+               $this->is_embed = isset( $qv['embed'] ) && ( $this->is_singular || $this->is_404 );
+
+               $this->query_vars_hash = md5( serialize( $this->query_vars ) );
+               $this->query_vars_changed = false;
+
+               /**
+                * Fires after the main query vars have been parsed.
+                *
+                * @since 1.5.0
+                *
+                * @param WP_Query &$this The WP_Query instance (passed by reference).
+                */
+               do_action_ref_array( 'parse_query', array( &$this ) );
        }
 
-       /*
+       /**
         * Parses various taxonomy related query vars.
         *
+        * For BC, this method is not marked as protected. See [28987].
+        *
         * @access protected
         * @since 3.1.0
         *
         * @param array &$q The query variables
         */
-       function parse_tax_query( &$q ) {
+       public function parse_tax_query( &$q ) {
                if ( ! empty( $q['tax_query'] ) && is_array( $q['tax_query'] ) ) {
                        $tax_query = $q['tax_query'];
                } else {
@@ -1653,7 +1931,10 @@ class WP_Query {
                        );
                }
 
-               foreach ( $GLOBALS['wp_taxonomies'] as $taxonomy => $t ) {
+               foreach ( get_taxonomies( array() , 'objects' ) as $taxonomy => $t ) {
+                       if ( 'post_tag' == $taxonomy )
+                               continue;       // Handled further down in the $q['tag'] block
+
                        if ( $t->query_var && !empty( $q[$t->query_var] ) ) {
                                $tax_query_defaults = array(
                                        'taxonomy' => $taxonomy,
@@ -1666,6 +1947,10 @@ class WP_Query {
 
                                $term = $q[$t->query_var];
 
+                               if ( is_array( $term ) ) {
+                                       $term = implode( ',', $term );
+                               }
+
                                if ( strpos($term, '+') !== false ) {
                                        $terms = preg_split( '/[+]+/', $term );
                                        foreach ( $terms as $term ) {
@@ -1681,31 +1966,57 @@ class WP_Query {
                        }
                }
 
+               // If querystring 'cat' is an array, implode it.
+               if ( is_array( $q['cat'] ) ) {
+                       $q['cat'] = implode( ',', $q['cat'] );
+               }
+
                // Category stuff
-               if ( !empty($q['cat']) && '0' != $q['cat'] && !$this->is_singular && !$this->parsed_tax_query ) {
-                       $q['cat'] = ''.urldecode($q['cat']).'';
-                       $q['cat'] = addslashes_gpc($q['cat']);
-                       $cat_array = preg_split('/[,\s]+/', $q['cat']);
-                       $q['cat'] = '';
-                       $req_cats = array();
-                       foreach ( (array) $cat_array as $cat ) {
-                               $cat = intval($cat);
-                               $req_cats[] = $cat;
-                               $in = ($cat > 0);
-                               $cat = abs($cat);
-                               if ( $in ) {
-                                       $q['category__in'][] = $cat;
-                                       $q['category__in'] = array_merge( $q['category__in'], get_term_children($cat, 'category') );
-                               } else {
-                                       $q['category__not_in'][] = $cat;
-                                       $q['category__not_in'] = array_merge( $q['category__not_in'], get_term_children($cat, 'category') );
-                               }
+               if ( ! empty( $q['cat'] ) && ! $this->is_singular ) {
+                       $cat_in = $cat_not_in = array();
+
+                       $cat_array = preg_split( '/[,\s]+/', urldecode( $q['cat'] ) );
+                       $cat_array = array_map( 'intval', $cat_array );
+                       $q['cat'] = implode( ',', $cat_array );
+
+                       foreach ( $cat_array as $cat ) {
+                               if ( $cat > 0 )
+                                       $cat_in[] = $cat;
+                               elseif ( $cat < 0 )
+                                       $cat_not_in[] = abs( $cat );
+                       }
+
+                       if ( ! empty( $cat_in ) ) {
+                               $tax_query[] = array(
+                                       'taxonomy' => 'category',
+                                       'terms' => $cat_in,
+                                       'field' => 'term_id',
+                                       'include_children' => true
+                               );
                        }
-                       $q['cat'] = implode(',', $req_cats);
+
+                       if ( ! empty( $cat_not_in ) ) {
+                               $tax_query[] = array(
+                                       'taxonomy' => 'category',
+                                       'terms' => $cat_not_in,
+                                       'field' => 'term_id',
+                                       'operator' => 'NOT IN',
+                                       'include_children' => true
+                               );
+                       }
+                       unset( $cat_array, $cat_in, $cat_not_in );
+               }
+
+               if ( ! empty( $q['category__and'] ) && 1 === count( (array) $q['category__and'] ) ) {
+                       $q['category__and'] = (array) $q['category__and'];
+                       if ( ! isset( $q['category__in'] ) )
+                               $q['category__in'] = array();
+                       $q['category__in'][] = absint( reset( $q['category__and'] ) );
+                       unset( $q['category__and'] );
                }
 
-               if ( !empty($q['category__in']) ) {
-                       $q['category__in'] = array_map('absint', array_unique( (array) $q['category__in'] ) );
+               if ( ! empty( $q['category__in'] ) ) {
+                       $q['category__in'] = array_map( 'absint', array_unique( (array) $q['category__in'] ) );
                        $tax_query[] = array(
                                'taxonomy' => 'category',
                                'terms' => $q['category__in'],
@@ -1714,8 +2025,8 @@ class WP_Query {
                        );
                }
 
-               if ( !empty($q['category__not_in']) ) {
-                       $q['category__not_in'] = array_map('absint', array_unique( (array) $q['category__not_in'] ) );
+               if ( ! empty($q['category__not_in']) ) {
+                       $q['category__not_in'] = array_map( 'absint', array_unique( (array) $q['category__not_in'] ) );
                        $tax_query[] = array(
                                'taxonomy' => 'category',
                                'terms' => $q['category__not_in'],
@@ -1724,8 +2035,8 @@ class WP_Query {
                        );
                }
 
-               if ( !empty($q['category__and']) ) {
-                       $q['category__and'] = array_map('absint', array_unique( (array) $q['category__and'] ) );
+               if ( ! empty($q['category__and']) ) {
+                       $q['category__and'] = array_map( 'absint', array_unique( (array) $q['category__and'] ) );
                        $tax_query[] = array(
                                'taxonomy' => 'category',
                                'terms' => $q['category__and'],
@@ -1735,16 +2046,21 @@ class WP_Query {
                        );
                }
 
+               // If querystring 'tag' is array, implode it.
+               if ( is_array( $q['tag'] ) ) {
+                       $q['tag'] = implode( ',', $q['tag'] );
+               }
+
                // Tag stuff
-               if ( '' != $q['tag'] && !$this->is_singular && !$this->parsed_tax_query ) {
+               if ( '' != $q['tag'] && !$this->is_singular && $this->query_vars_changed ) {
                        if ( strpos($q['tag'], ',') !== false ) {
-                               $tags = preg_split('/[,\s]+/', $q['tag']);
+                               $tags = preg_split('/[,\r\n\t ]+/', $q['tag']);
                                foreach ( (array) $tags as $tag ) {
                                        $tag = sanitize_term_field('slug', $tag, 0, 'post_tag', 'db');
                                        $q['tag_slug__in'][] = $tag;
                                }
-                       } else if ( preg_match('/[+\s]+/', $q['tag']) || !empty($q['cat']) ) {
-                               $tags = preg_split('/[+\s]+/', $q['tag']);
+                       } elseif ( preg_match('/[+\r\n\t ]+/', $q['tag'] ) || ! empty( $q['cat'] ) ) {
+                               $tags = preg_split('/[+\r\n\t ]+/', $q['tag']);
                                foreach ( (array) $tags as $tag ) {
                                        $tag = sanitize_term_field('slug', $tag, 0, 'post_tag', 'db');
                                        $q['tag_slug__and'][] = $tag;
@@ -1790,7 +2106,7 @@ class WP_Query {
                }
 
                if ( !empty($q['tag_slug__in']) ) {
-                       $q['tag_slug__in'] = array_map('sanitize_title', (array) $q['tag_slug__in']);
+                       $q['tag_slug__in'] = array_map('sanitize_title_for_query', array_unique( (array) $q['tag_slug__in'] ) );
                        $tax_query[] = array(
                                'taxonomy' => 'post_tag',
                                'terms' => $q['tag_slug__in'],
@@ -1799,7 +2115,7 @@ class WP_Query {
                }
 
                if ( !empty($q['tag_slug__and']) ) {
-                       $q['tag_slug__and'] = array_map('sanitize_title', (array) $q['tag_slug__and']);
+                       $q['tag_slug__and'] = array_map('sanitize_title_for_query', array_unique( (array) $q['tag_slug__and'] ) );
                        $tax_query[] = array(
                                'taxonomy' => 'post_tag',
                                'terms' => $q['tag_slug__and'],
@@ -1808,110 +2124,445 @@ class WP_Query {
                        );
                }
 
-               $this->parsed_tax_query = true;
-
                $this->tax_query = new WP_Tax_Query( $tax_query );
+
+               /**
+                * Fires after taxonomy-related query vars have been parsed.
+                *
+                * @since 3.7.0
+                *
+                * @param WP_Query $this The WP_Query instance.
+                */
+               do_action( 'parse_tax_query', $this );
        }
 
        /**
-        * Sets the 404 property and saves whether query is feed.
+        * Generate SQL for the WHERE clause based on passed search terms.
         *
-        * @since 2.0.0
-        * @access public
+        * @since 3.7.0
+        *
+        * @global wpdb $wpdb WordPress database abstraction object.
+        *
+        * @param array $q Query variables.
+        * @return string WHERE clause.
         */
-       function set_404() {
-               $is_feed = $this->is_feed;
+       protected function parse_search( &$q ) {
+               global $wpdb;
 
-               $this->init_query_flags();
-               $this->is_404 = true;
+               $search = '';
 
-               $this->is_feed = $is_feed;
+               // added slashes screw with quote grouping when done early, so done later
+               $q['s'] = stripslashes( $q['s'] );
+               if ( empty( $_GET['s'] ) && $this->is_main_query() )
+                       $q['s'] = urldecode( $q['s'] );
+               // there are no line breaks in <input /> fields
+               $q['s'] = str_replace( array( "\r", "\n" ), '', $q['s'] );
+               $q['search_terms_count'] = 1;
+               if ( ! empty( $q['sentence'] ) ) {
+                       $q['search_terms'] = array( $q['s'] );
+               } else {
+                       if ( preg_match_all( '/".*?("|$)|((?<=[\t ",+])|^)[^\t ",+]+/', $q['s'], $matches ) ) {
+                               $q['search_terms_count'] = count( $matches[0] );
+                               $q['search_terms'] = $this->parse_search_terms( $matches[0] );
+                               // if the search string has only short terms or stopwords, or is 10+ terms long, match it as sentence
+                               if ( empty( $q['search_terms'] ) || count( $q['search_terms'] ) > 9 )
+                                       $q['search_terms'] = array( $q['s'] );
+                       } else {
+                               $q['search_terms'] = array( $q['s'] );
+                       }
+               }
+
+               $n = ! empty( $q['exact'] ) ? '' : '%';
+               $searchand = '';
+               $q['search_orderby_title'] = array();
+               foreach ( $q['search_terms'] as $term ) {
+                       // Terms prefixed with '-' should be excluded.
+                       $include = '-' !== substr( $term, 0, 1 );
+                       if ( $include ) {
+                               $like_op  = 'LIKE';
+                               $andor_op = 'OR';
+                       } else {
+                               $like_op  = 'NOT LIKE';
+                               $andor_op = 'AND';
+                               $term     = substr( $term, 1 );
+                       }
+
+                       if ( $n && $include ) {
+                               $like = '%' . $wpdb->esc_like( $term ) . '%';
+                               $q['search_orderby_title'][] = $wpdb->prepare( "$wpdb->posts.post_title LIKE %s", $like );
+                       }
+
+                       $like = $n . $wpdb->esc_like( $term ) . $n;
+                       $search .= $wpdb->prepare( "{$searchand}(($wpdb->posts.post_title $like_op %s) $andor_op ($wpdb->posts.post_content $like_op %s))", $like, $like );
+                       $searchand = ' AND ';
+               }
+
+               if ( ! empty( $search ) ) {
+                       $search = " AND ({$search}) ";
+                       if ( ! is_user_logged_in() )
+                               $search .= " AND ($wpdb->posts.post_password = '') ";
+               }
+
+               return $search;
        }
 
        /**
-        * Retrieve query variable.
+        * Check if the terms are suitable for searching.
         *
-        * @since 1.5.0
-        * @access public
+        * Uses an array of stopwords (terms) that are excluded from the separate
+        * term matching when searching for posts. The list of English stopwords is
+        * the approximate search engines list, and is translatable.
         *
-        * @param string $query_var Query variable key.
-        * @return mixed
+        * @since 3.7.0
+        *
+        * @param array $terms Terms to check.
+        * @return array Terms that are not stopwords.
         */
-       function get($query_var) {
-               if ( isset($this->query_vars[$query_var]) )
-                       return $this->query_vars[$query_var];
+       protected function parse_search_terms( $terms ) {
+               $strtolower = function_exists( 'mb_strtolower' ) ? 'mb_strtolower' : 'strtolower';
+               $checked = array();
+
+               $stopwords = $this->get_search_stopwords();
 
-               return '';
+               foreach ( $terms as $term ) {
+                       // keep before/after spaces when term is for exact match
+                       if ( preg_match( '/^".+"$/', $term ) )
+                               $term = trim( $term, "\"'" );
+                       else
+                               $term = trim( $term, "\"' " );
+
+                       // Avoid single A-Z.
+                       if ( ! $term || ( 1 === strlen( $term ) && preg_match( '/^[a-z]$/i', $term ) ) )
+                               continue;
+
+                       if ( in_array( call_user_func( $strtolower, $term ), $stopwords, true ) )
+                               continue;
+
+                       $checked[] = $term;
+               }
+
+               return $checked;
        }
 
        /**
-        * Set query variable.
+        * Retrieve stopwords used when parsing search terms.
         *
-        * @since 1.5.0
-        * @access public
+        * @since 3.7.0
         *
-        * @param string $query_var Query variable key.
-        * @param mixed $value Query variable value.
+        * @return array Stopwords.
         */
-       function set($query_var, $value) {
-               $this->query_vars[$query_var] = $value;
+       protected function get_search_stopwords() {
+               if ( isset( $this->stopwords ) )
+                       return $this->stopwords;
+
+               /* translators: This is a comma-separated list of very common words that should be excluded from a search,
+                * like a, an, and the. These are usually called "stopwords". You should not simply translate these individual
+                * words into your language. Instead, look for and provide commonly accepted stopwords in your language.
+                */
+               $words = explode( ',', _x( 'about,an,are,as,at,be,by,com,for,from,how,in,is,it,of,on,or,that,the,this,to,was,what,when,where,who,will,with,www',
+                       'Comma-separated list of search stopwords in your language' ) );
+
+               $stopwords = array();
+               foreach ( $words as $word ) {
+                       $word = trim( $word, "\r\n\t " );
+                       if ( $word )
+                               $stopwords[] = $word;
+               }
+
+               /**
+                * Filter stopwords used when parsing search terms.
+                *
+                * @since 3.7.0
+                *
+                * @param array $stopwords Stopwords.
+                */
+               $this->stopwords = apply_filters( 'wp_search_stopwords', $stopwords );
+               return $this->stopwords;
        }
 
        /**
-        * Retrieve the posts based on query variables.
-        *
-        * There are a few filters and actions that can be used to modify the post
-        * database query.
+        * Generate SQL for the ORDER BY condition based on passed search terms.
         *
-        * @since 1.5.0
-        * @access public
-        * @uses do_action_ref_array() Calls 'pre_get_posts' hook before retrieving posts.
+        * @global wpdb $wpdb WordPress database abstraction object.
         *
-        * @return array List of posts.
+        * @param array $q Query variables.
+        * @return string ORDER BY clause.
         */
-       function &get_posts() {
-               global $wpdb, $user_ID, $_wp_using_ext_object_cache;
+       protected function parse_search_order( &$q ) {
+               global $wpdb;
 
-               $this->parse_query();
+               if ( $q['search_terms_count'] > 1 ) {
+                       $num_terms = count( $q['search_orderby_title'] );
 
-               do_action_ref_array('pre_get_posts', array(&$this));
+                       // If the search terms contain negative queries, don't bother ordering by sentence matches.
+                       $like = '';
+                       if ( ! preg_match( '/(?:\s|^)\-/', $q['s'] ) ) {
+                               $like = '%' . $wpdb->esc_like( $q['s'] ) . '%';
+                       }
 
-               // Shorthand.
-               $q = &$this->query_vars;
+                       $search_orderby = '(CASE ';
 
-               $q = $this->fill_query_vars($q);
+                       // sentence match in 'post_title'
+                       if ( $like ) {
+                               $search_orderby .= $wpdb->prepare( "WHEN $wpdb->posts.post_title LIKE %s THEN 1 ", $like );
+                       }
 
-               // First let's clear some variables
-               $distinct = '';
-               $whichauthor = '';
-               $whichmimetype = '';
-               $where = '';
-               $limits = '';
-               $join = '';
-               $search = '';
-               $groupby = '';
-               $fields = '';
-               $post_status_join = false;
-               $page = 1;
+                       // sanity limit, sort as sentence when more than 6 terms
+                       // (few searches are longer than 6 terms and most titles are not)
+                       if ( $num_terms < 7 ) {
+                               // all words in title
+                               $search_orderby .= 'WHEN ' . implode( ' AND ', $q['search_orderby_title'] ) . ' THEN 2 ';
+                               // any word in title, not needed when $num_terms == 1
+                               if ( $num_terms > 1 )
+                                       $search_orderby .= 'WHEN ' . implode( ' OR ', $q['search_orderby_title'] ) . ' THEN 3 ';
+                       }
 
-               if ( isset( $q['caller_get_posts'] ) ) {
-                       _deprecated_argument( 'WP_Query', '3.1', __( '"caller_get_posts" is deprecated. Use "ignore_sticky_posts" instead.' ) );
-                       if ( !isset( $q['ignore_sticky_posts'] ) )
-                               $q['ignore_sticky_posts'] = $q['caller_get_posts'];
+                       // sentence match in 'post_content'
+                       if ( $like ) {
+                               $search_orderby .= $wpdb->prepare( "WHEN $wpdb->posts.post_content LIKE %s THEN 4 ", $like );
+                       }
+                       $search_orderby .= 'ELSE 5 END)';
+               } else {
+                       // single word or sentence search
+                       $search_orderby = reset( $q['search_orderby_title'] ) . ' DESC';
                }
 
-               if ( !isset( $q['ignore_sticky_posts'] ) )
-                       $q['ignore_sticky_posts'] = false;
-
-               if ( !isset($q['suppress_filters']) )
-                       $q['suppress_filters'] = false;
+               return $search_orderby;
+       }
 
-               if ( !isset($q['cache_results']) ) {
-                       if ( $_wp_using_ext_object_cache )
-                               $q['cache_results'] = false;
-                       else
-                               $q['cache_results'] = true;
-               }
+       /**
+        * If the passed orderby value is allowed, convert the alias to a
+        * properly-prefixed orderby value.
+        *
+        * @since 4.0.0
+        * @access protected
+        *
+        * @global wpdb $wpdb WordPress database abstraction object.
+        *
+        * @param string $orderby Alias for the field to order by.
+        * @return string|false Table-prefixed value to used in the ORDER clause. False otherwise.
+        */
+       protected function parse_orderby( $orderby ) {
+               global $wpdb;
+
+               // Used to filter values.
+               $allowed_keys = array(
+                       'post_name', 'post_author', 'post_date', 'post_title', 'post_modified',
+                       'post_parent', 'post_type', 'name', 'author', 'date', 'title', 'modified',
+                       'parent', 'type', 'ID', 'menu_order', 'comment_count', 'rand',
+               );
+
+               $primary_meta_key = '';
+               $primary_meta_query = false;
+               $meta_clauses = $this->meta_query->get_clauses();
+               if ( ! empty( $meta_clauses ) ) {
+                       $primary_meta_query = reset( $meta_clauses );
+
+                       if ( ! empty( $primary_meta_query['key'] ) ) {
+                               $primary_meta_key = $primary_meta_query['key'];
+                               $allowed_keys[] = $primary_meta_key;
+                       }
+
+                       $allowed_keys[] = 'meta_value';
+                       $allowed_keys[] = 'meta_value_num';
+                       $allowed_keys   = array_merge( $allowed_keys, array_keys( $meta_clauses ) );
+               }
+
+               if ( ! in_array( $orderby, $allowed_keys, true ) ) {
+                       return false;
+               }
+
+               switch ( $orderby ) {
+                       case 'post_name':
+                       case 'post_author':
+                       case 'post_date':
+                       case 'post_title':
+                       case 'post_modified':
+                       case 'post_parent':
+                       case 'post_type':
+                       case 'ID':
+                       case 'menu_order':
+                       case 'comment_count':
+                               $orderby_clause = "$wpdb->posts.{$orderby}";
+                               break;
+                       case 'rand':
+                               $orderby_clause = 'RAND()';
+                               break;
+                       case $primary_meta_key:
+                       case 'meta_value':
+                               if ( ! empty( $primary_meta_query['type'] ) ) {
+                                       $orderby_clause = "CAST({$primary_meta_query['alias']}.meta_value AS {$primary_meta_query['cast']})";
+                               } else {
+                                       $orderby_clause = "{$primary_meta_query['alias']}.meta_value";
+                               }
+                               break;
+                       case 'meta_value_num':
+                               $orderby_clause = "{$primary_meta_query['alias']}.meta_value+0";
+                               break;
+                       default:
+                               if ( array_key_exists( $orderby, $meta_clauses ) ) {
+                                       // $orderby corresponds to a meta_query clause.
+                                       $meta_clause = $meta_clauses[ $orderby ];
+                                       $orderby_clause = "CAST({$meta_clause['alias']}.meta_value AS {$meta_clause['cast']})";
+                               } else {
+                                       // Default: order by post field.
+                                       $orderby_clause = "$wpdb->posts.post_" . sanitize_key( $orderby );
+                               }
+
+                               break;
+               }
+
+               return $orderby_clause;
+       }
+
+       /**
+        * Parse an 'order' query variable and cast it to ASC or DESC as necessary.
+        *
+        * @since 4.0.0
+        * @access protected
+        *
+        * @param string $order The 'order' query variable.
+        * @return string The sanitized 'order' query variable.
+        */
+       protected function parse_order( $order ) {
+               if ( ! is_string( $order ) || empty( $order ) ) {
+                       return 'DESC';
+               }
+
+               if ( 'ASC' === strtoupper( $order ) ) {
+                       return 'ASC';
+               } else {
+                       return 'DESC';
+               }
+       }
+
+       /**
+        * Sets the 404 property and saves whether query is feed.
+        *
+        * @since 2.0.0
+        * @access public
+        */
+       public function set_404() {
+               $is_feed = $this->is_feed;
+
+               $this->init_query_flags();
+               $this->is_404 = true;
+
+               $this->is_feed = $is_feed;
+       }
+
+       /**
+        * Retrieve query variable.
+        *
+        * @since 1.5.0
+        * @since 3.9.0 The `$default` argument was introduced.
+        *
+        * @access public
+        *
+        * @param string $query_var Query variable key.
+        * @param mixed  $default   Optional. Value to return if the query variable is not set. Default empty.
+        * @return mixed Contents of the query variable.
+        */
+       public function get( $query_var, $default = '' ) {
+               if ( isset( $this->query_vars[ $query_var ] ) ) {
+                       return $this->query_vars[ $query_var ];
+               }
+
+               return $default;
+       }
+
+       /**
+        * Set query variable.
+        *
+        * @since 1.5.0
+        * @access public
+        *
+        * @param string $query_var Query variable key.
+        * @param mixed  $value     Query variable value.
+        */
+       public function set($query_var, $value) {
+               $this->query_vars[$query_var] = $value;
+       }
+
+       /**
+        * Retrieve the posts based on query variables.
+        *
+        * There are a few filters and actions that can be used to modify the post
+        * database query.
+        *
+        * @since 1.5.0
+        * @access public
+        *
+        * @global wpdb $wpdb WordPress database abstraction object.
+        *
+        * @return array List of posts.
+        */
+       public function get_posts() {
+               global $wpdb;
+
+               $this->parse_query();
+
+               /**
+                * Fires after the query variable object is created, but before the actual query is run.
+                *
+                * Note: If using conditional tags, use the method versions within the passed instance
+                * (e.g. $this->is_main_query() instead of is_main_query()). This is because the functions
+                * like is_main_query() test against the global $wp_query instance, not the passed one.
+                *
+                * @since 2.0.0
+                *
+                * @param WP_Query &$this The WP_Query instance (passed by reference).
+                */
+               do_action_ref_array( 'pre_get_posts', array( &$this ) );
+
+               // Shorthand.
+               $q = &$this->query_vars;
+
+               // Fill again in case pre_get_posts unset some vars.
+               $q = $this->fill_query_vars($q);
+
+               // Parse meta query
+               $this->meta_query = new WP_Meta_Query();
+               $this->meta_query->parse_query_vars( $q );
+
+               // Set a flag if a pre_get_posts hook changed the query vars.
+               $hash = md5( serialize( $this->query_vars ) );
+               if ( $hash != $this->query_vars_hash ) {
+                       $this->query_vars_changed = true;
+                       $this->query_vars_hash = $hash;
+               }
+               unset($hash);
+
+               // First let's clear some variables
+               $distinct = '';
+               $whichauthor = '';
+               $whichmimetype = '';
+               $where = '';
+               $limits = '';
+               $join = '';
+               $search = '';
+               $groupby = '';
+               $post_status_join = false;
+               $page = 1;
+
+               if ( isset( $q['caller_get_posts'] ) ) {
+                       _deprecated_argument( 'WP_Query', '3.1', __( '"caller_get_posts" is deprecated. Use "ignore_sticky_posts" instead.' ) );
+                       if ( !isset( $q['ignore_sticky_posts'] ) )
+                               $q['ignore_sticky_posts'] = $q['caller_get_posts'];
+               }
+
+               if ( !isset( $q['ignore_sticky_posts'] ) )
+                       $q['ignore_sticky_posts'] = false;
+
+               if ( !isset($q['suppress_filters']) )
+                       $q['suppress_filters'] = false;
+
+               if ( !isset($q['cache_results']) ) {
+                       if ( wp_using_ext_object_cache() )
+                               $q['cache_results'] = false;
+                       else
+                               $q['cache_results'] = true;
+               }
 
                if ( !isset($q['update_post_term_cache']) )
                        $q['update_post_term_cache'] = true;
@@ -1926,8 +2577,9 @@ class WP_Query {
                                $q['post_type'] = '';
                }
                $post_type = $q['post_type'];
-               if ( !isset($q['posts_per_page']) || $q['posts_per_page'] == 0 )
-                       $q['posts_per_page'] = get_option('posts_per_page');
+               if ( empty( $q['posts_per_page'] ) ) {
+                       $q['posts_per_page'] = get_option( 'posts_per_page' );
+               }
                if ( isset($q['showposts']) && $q['showposts'] ) {
                        $q['showposts'] = (int) $q['showposts'];
                        $q['posts_per_page'] = $q['showposts'];
@@ -1941,14 +2593,20 @@ class WP_Query {
                                $q['nopaging'] = false;
                        }
                }
+
                if ( $this->is_feed ) {
-                       $q['posts_per_page'] = get_option('posts_per_rss');
+                       // This overrides posts_per_page.
+                       if ( ! empty( $q['posts_per_rss'] ) ) {
+                               $q['posts_per_page'] = $q['posts_per_rss'];
+                       } else {
+                               $q['posts_per_page'] = get_option( 'posts_per_rss' );
+                       }
                        $q['nopaging'] = false;
                }
                $q['posts_per_page'] = (int) $q['posts_per_page'];
                if ( $q['posts_per_page'] < -1 )
                        $q['posts_per_page'] = abs($q['posts_per_page']);
-               else if ( $q['posts_per_page'] == 0 )
+               elseif ( $q['posts_per_page'] == 0 )
                        $q['posts_per_page'] = 1;
 
                if ( !isset($q['comments_per_page']) || $q['comments_per_page'] == 0 )
@@ -1982,9 +2640,11 @@ class WP_Query {
                                $fields = "$wpdb->posts.*";
                }
 
-               // If a month is specified in the querystring, load that month
+               if ( '' !== $q['menu_order'] )
+                       $where .= " AND $wpdb->posts.menu_order = " . $q['menu_order'];
+
+               // The "m" parameter is meant for months but accepts datetimes of varying specificity
                if ( $q['m'] ) {
-                       $q['m'] = '' . preg_replace('|[^0-9]|', '', $q['m']);
                        $where .= " AND YEAR($wpdb->posts.post_date)=" . substr($q['m'], 0, 4);
                        if ( strlen($q['m']) > 5 )
                                $where .= " AND MONTH($wpdb->posts.post_date)=" . substr($q['m'], 4, 2);
@@ -1998,36 +2658,55 @@ class WP_Query {
                                $where .= " AND SECOND($wpdb->posts.post_date)=" . substr($q['m'], 12, 2);
                }
 
+               // Handle the other individual date parameters
+               $date_parameters = array();
+
                if ( '' !== $q['hour'] )
-                       $where .= " AND HOUR($wpdb->posts.post_date)='" . $q['hour'] . "'";
+                       $date_parameters['hour'] = $q['hour'];
 
                if ( '' !== $q['minute'] )
-                       $where .= " AND MINUTE($wpdb->posts.post_date)='" . $q['minute'] . "'";
+                       $date_parameters['minute'] = $q['minute'];
 
                if ( '' !== $q['second'] )
-                       $where .= " AND SECOND($wpdb->posts.post_date)='" . $q['second'] . "'";
+                       $date_parameters['second'] = $q['second'];
 
                if ( $q['year'] )
-                       $where .= " AND YEAR($wpdb->posts.post_date)='" . $q['year'] . "'";
+                       $date_parameters['year'] = $q['year'];
 
                if ( $q['monthnum'] )
-                       $where .= " AND MONTH($wpdb->posts.post_date)='" . $q['monthnum'] . "'";
+                       $date_parameters['monthnum'] = $q['monthnum'];
+
+               if ( $q['w'] )
+                       $date_parameters['week'] = $q['w'];
 
                if ( $q['day'] )
-                       $where .= " AND DAYOFMONTH($wpdb->posts.post_date)='" . $q['day'] . "'";
+                       $date_parameters['day'] = $q['day'];
+
+               if ( $date_parameters ) {
+                       $date_query = new WP_Date_Query( array( $date_parameters ) );
+                       $where .= $date_query->get_sql();
+               }
+               unset( $date_parameters, $date_query );
+
+               // Handle complex date queries
+               if ( ! empty( $q['date_query'] ) ) {
+                       $this->date_query = new WP_Date_Query( $q['date_query'] );
+                       $where .= $this->date_query->get_sql();
+               }
+
 
-               // If we've got a post_type AND its not "any" post_type.
+               // If we've got a post_type AND it's not "any" post_type.
                if ( !empty($q['post_type']) && 'any' != $q['post_type'] ) {
                        foreach ( (array)$q['post_type'] as $_post_type ) {
                                $ptype_obj = get_post_type_object($_post_type);
                                if ( !$ptype_obj || !$ptype_obj->query_var || empty($q[ $ptype_obj->query_var ]) )
                                        continue;
 
-                               if ( ! $ptype_obj->hierarchical || strpos($q[ $ptype_obj->query_var ], '/') === false ) {
-                                       // Non-hierarchical post_types & parent-level-hierarchical post_types can directly use 'name'
+                               if ( ! $ptype_obj->hierarchical ) {
+                                       // Non-hierarchical post types can directly use 'name'.
                                        $q['name'] = $q[ $ptype_obj->query_var ];
                                } else {
-                                       // Hierarchical post_types will operate through the
+                                       // Hierarchical post types will operate through 'pagename'.
                                        $q['pagename'] = $q[ $ptype_obj->query_var ];
                                        $q['name'] = '';
                                }
@@ -2038,6 +2717,11 @@ class WP_Query {
                        unset($ptype_obj);
                }
 
+               if ( '' !== $q['title'] ) {
+                       $where .= $wpdb->prepare( " AND $wpdb->posts.post_title = %s", stripslashes( $q['title'] ) );
+               }
+
+               // Parameters related to 'post_name'.
                if ( '' != $q['name'] ) {
                        $q['name'] = sanitize_title_for_query( $q['name'] );
                        $where .= " AND $wpdb->posts.post_name = '" . $q['name'] . "'";
@@ -2070,7 +2754,7 @@ class WP_Query {
                                $q['pagename'] = sanitize_title_for_query( wp_basename( $q['pagename'] ) );
                                $q['name'] = $q['pagename'];
                                $where .= " AND ($wpdb->posts.ID = '$reqpage')";
-                               $reqpage_obj = get_page($reqpage);
+                               $reqpage_obj = get_post( $reqpage );
                                if ( is_object($reqpage_obj) && 'attachment' == $reqpage_obj->post_type ) {
                                        $this->is_attachment = true;
                                        $post_type = $q['post_type'] = 'attachment';
@@ -2082,15 +2766,15 @@ class WP_Query {
                        $q['attachment'] = sanitize_title_for_query( wp_basename( $q['attachment'] ) );
                        $q['name'] = $q['attachment'];
                        $where .= " AND $wpdb->posts.post_name = '" . $q['attachment'] . "'";
+               } elseif ( is_array( $q['post_name__in'] ) && ! empty( $q['post_name__in'] ) ) {
+                       $q['post_name__in'] = array_map( 'sanitize_title_for_query', $q['post_name__in'] );
+                       $where .= " AND $wpdb->posts.post_name IN ('" . implode( "' ,'", $q['post_name__in'] ) . "')";
                }
 
-               if ( $q['w'] )
-                       $where .= ' AND ' . _wp_mysql_week( "`$wpdb->posts`.`post_date`" ) . " = '" . $q['w'] . "'";
-
                if ( intval($q['comments_popup']) )
                        $q['p'] = absint($q['comments_popup']);
 
-               // If an attachment is requested by number, let it supercede any post number.
+               // If an attachment is requested by number, let it supersede any post number.
                if ( $q['attachment_id'] )
                        $q['p'] = absint($q['attachment_id']);
 
@@ -2105,8 +2789,15 @@ class WP_Query {
                        $where .= " AND {$wpdb->posts}.ID NOT IN ($post__not_in)";
                }
 
-               if ( is_numeric($q['post_parent']) )
+               if ( is_numeric( $q['post_parent'] ) ) {
                        $where .= $wpdb->prepare( " AND $wpdb->posts.post_parent = %d ", $q['post_parent'] );
+               } elseif ( $q['post_parent__in'] ) {
+                       $post_parent__in = implode( ',', array_map( 'absint', $q['post_parent__in'] ) );
+                       $where .= " AND {$wpdb->posts}.post_parent IN ($post_parent__in)";
+               } elseif ( $q['post_parent__not_in'] ) {
+                       $post_parent__not_in = implode( ',',  array_map( 'absint', $q['post_parent__not_in'] ) );
+                       $where .= " AND {$wpdb->posts}.post_parent NOT IN ($post_parent__not_in)";
+               }
 
                if ( $q['page_id'] ) {
                        if  ( ('page' != get_option('show_on_front') ) || ( $q['page_id'] != get_option('page_for_posts') ) ) {
@@ -2115,123 +2806,127 @@ class WP_Query {
                        }
                }
 
-               // If a search pattern is specified, load the posts that match
-               if ( !empty($q['s']) ) {
-                       // added slashes screw with quote grouping when done early, so done later
-                       $q['s'] = stripslashes($q['s']);
-                       if ( !empty($q['sentence']) ) {
-                               $q['search_terms'] = array($q['s']);
-                       } else {
-                               preg_match_all('/".*?("|$)|((?<=[\\s",+])|^)[^\\s",+]+/', $q['s'], $matches);
-                               $q['search_terms'] = array_map('_search_terms_tidy', $matches[0]);
-                       }
-                       $n = !empty($q['exact']) ? '' : '%';
-                       $searchand = '';
-                       foreach( (array) $q['search_terms'] as $term ) {
-                               $term = esc_sql( like_escape( $term ) );
-                               $search .= "{$searchand}(($wpdb->posts.post_title LIKE '{$n}{$term}{$n}') OR ($wpdb->posts.post_content LIKE '{$n}{$term}{$n}'))";
-                               $searchand = ' AND ';
-                       }
-                       $term = esc_sql( like_escape( $q['s'] ) );
-                       if ( empty($q['sentence']) && count($q['search_terms']) > 1 && $q['search_terms'][0] != $q['s'] )
-                               $search .= " OR ($wpdb->posts.post_title LIKE '{$n}{$term}{$n}') OR ($wpdb->posts.post_content LIKE '{$n}{$term}{$n}')";
-
-                       if ( !empty($search) ) {
-                               $search = " AND ({$search}) ";
-                               if ( !is_user_logged_in() )
-                                       $search .= " AND ($wpdb->posts.post_password = '') ";
-                       }
+               // If a search pattern is specified, load the posts that match.
+               if ( ! empty( $q['s'] ) ) {
+                       $search = $this->parse_search( $q );
                }
 
-               // Allow plugins to contextually add/remove/modify the search section of the database query
-               $search = apply_filters_ref_array('posts_search', array( $search, &$this ) );
+               /**
+                * Filter the search SQL that is used in the WHERE clause of WP_Query.
+                *
+                * @since 3.0.0
+                *
+                * @param string   $search Search SQL for WHERE clause.
+                * @param WP_Query $this   The current WP_Query object.
+                */
+               $search = apply_filters_ref_array( 'posts_search', array( $search, &$this ) );
 
                // Taxonomies
-               $this->parse_tax_query( $q );
+               if ( !$this->is_singular ) {
+                       $this->parse_tax_query( $q );
 
-               $clauses = $this->tax_query->get_sql( $wpdb->posts, 'ID' );
+                       $clauses = $this->tax_query->get_sql( $wpdb->posts, 'ID' );
 
-               $join .= $clauses['join'];
-               $where .= $clauses['where'];
+                       $join .= $clauses['join'];
+                       $where .= $clauses['where'];
+               }
 
                if ( $this->is_tax ) {
                        if ( empty($post_type) ) {
-                               $post_type = 'any';
+                               // Do a fully inclusive search for currently registered post types of queried taxonomies
+                               $post_type = array();
+                               $taxonomies = array_keys( $this->tax_query->queried_terms );
+                               foreach ( get_post_types( array( 'exclude_from_search' => false ) ) as $pt ) {
+                                       $object_taxonomies = $pt === 'attachment' ? get_taxonomies_for_attachments() : get_object_taxonomies( $pt );
+                                       if ( array_intersect( $taxonomies, $object_taxonomies ) )
+                                               $post_type[] = $pt;
+                               }
+                               if ( ! $post_type )
+                                       $post_type = 'any';
+                               elseif ( count( $post_type ) == 1 )
+                                       $post_type = $post_type[0];
+
                                $post_status_join = true;
                        } elseif ( in_array('attachment', (array) $post_type) ) {
                                $post_status_join = true;
                        }
                }
 
-               // Back-compat
-               if ( !empty($this->tax_query->queries) ) {
-                       $tax_query_in_and = wp_list_filter( $this->tax_query->queries, array( 'operator' => 'NOT IN' ), 'NOT' );
-                       if ( !empty( $tax_query_in_and ) ) {
-                               if ( !isset( $q['taxonomy'] ) ) {
-                                       foreach ( $tax_query_in_and as $a_tax_query ) {
-                                               if ( !in_array( $a_tax_query['taxonomy'], array( 'category', 'post_tag' ) ) ) {
-                                                       $q['taxonomy'] = $a_tax_query['taxonomy'];
-                                                       if ( 'slug' == $a_tax_query['field'] )
-                                                               $q['term'] = $a_tax_query['terms'][0];
-                                                       else
-                                                               $q['term_id'] = $a_tax_query['terms'][0];
+               /*
+                * Ensure that 'taxonomy', 'term', 'term_id', 'cat', and
+                * 'category_name' vars are set for backward compatibility.
+                */
+               if ( ! empty( $this->tax_query->queried_terms ) ) {
+
+                       /*
+                        * Set 'taxonomy', 'term', and 'term_id' to the
+                        * first taxonomy other than 'post_tag' or 'category'.
+                        */
+                       if ( ! isset( $q['taxonomy'] ) ) {
+                               foreach ( $this->tax_query->queried_terms as $queried_taxonomy => $queried_items ) {
+                                       if ( empty( $queried_items['terms'][0] ) ) {
+                                               continue;
+                                       }
 
-                                                       break;
+                                       if ( ! in_array( $queried_taxonomy, array( 'category', 'post_tag' ) ) ) {
+                                               $q['taxonomy'] = $queried_taxonomy;
+
+                                               if ( 'slug' === $queried_items['field'] ) {
+                                                       $q['term'] = $queried_items['terms'][0];
+                                               } else {
+                                                       $q['term_id'] = $queried_items['terms'][0];
                                                }
                                        }
                                }
+                       }
 
-                               $cat_query = wp_list_filter( $tax_query_in_and, array( 'taxonomy' => 'category' ) );
-                               if ( !empty( $cat_query ) ) {
-                                       $cat_query = reset( $cat_query );
-                                       $the_cat = get_term_by( $cat_query['field'], $cat_query['terms'][0], 'category' );
+                       // 'cat', 'category_name', 'tag_id'
+                       foreach ( $this->tax_query->queried_terms as $queried_taxonomy => $queried_items ) {
+                               if ( empty( $queried_items['terms'][0] ) ) {
+                                       continue;
+                               }
+
+                               if ( 'category' === $queried_taxonomy ) {
+                                       $the_cat = get_term_by( $queried_items['field'], $queried_items['terms'][0], 'category' );
                                        if ( $the_cat ) {
                                                $this->set( 'cat', $the_cat->term_id );
                                                $this->set( 'category_name', $the_cat->slug );
                                        }
                                        unset( $the_cat );
                                }
-                               unset( $cat_query );
 
-                               $tag_query = wp_list_filter( $tax_query_in_and, array( 'taxonomy' => 'post_tag' ) );
-                               if ( !empty( $tag_query ) ) {
-                                       $tag_query = reset( $tag_query );
-                                       $the_tag = get_term_by( $tag_query['field'], $tag_query['terms'][0], 'post_tag' );
+                               if ( 'post_tag' === $queried_taxonomy ) {
+                                       $the_tag = get_term_by( $queried_items['field'], $queried_items['terms'][0], 'post_tag' );
                                        if ( $the_tag ) {
                                                $this->set( 'tag_id', $the_tag->term_id );
                                        }
                                        unset( $the_tag );
                                }
-                               unset( $tag_query );
                        }
                }
 
-               if ( !empty( $this->tax_query->queries ) || !empty( $q['meta_key'] ) ) {
+               if ( !empty( $this->tax_query->queries ) || !empty( $this->meta_query->queries ) ) {
                        $groupby = "{$wpdb->posts}.ID";
                }
 
                // Author/user stuff
 
-               if ( empty($q['author']) || ($q['author'] == '0') ) {
-                       $whichauthor = '';
-               } else {
-                       $q['author'] = (string)urldecode($q['author']);
-                       $q['author'] = addslashes_gpc($q['author']);
-                       if ( strpos($q['author'], '-') !== false ) {
-                               $eq = '!=';
-                               $andor = 'AND';
-                               $q['author'] = explode('-', $q['author']);
-                               $q['author'] = (string)absint($q['author'][1]);
-                       } else {
-                               $eq = '=';
-                               $andor = 'OR';
+               if ( ! empty( $q['author'] ) && $q['author'] != '0' ) {
+                       $q['author'] = addslashes_gpc( '' . urldecode( $q['author'] ) );
+                       $authors = array_unique( array_map( 'intval', preg_split( '/[,\s]+/', $q['author'] ) ) );
+                       foreach ( $authors as $author ) {
+                               $key = $author > 0 ? 'author__in' : 'author__not_in';
+                               $q[$key][] = abs( $author );
                        }
-                       $author_array = preg_split('/[,\s]+/', $q['author']);
-                       $_author_array = array();
-                       foreach ( $author_array as $key => $_author )
-                               $_author_array[] = "$wpdb->posts.post_author " . $eq . ' ' . absint($_author);
-                       $whichauthor .= ' AND (' . implode(" $andor ", $_author_array) . ')';
-                       unset($author_array, $_author_array);
+                       $q['author'] = implode( ',', $authors );
+               }
+
+               if ( ! empty( $q['author__not_in'] ) ) {
+                       $author__not_in = implode( ',', array_map( 'absint', array_unique( (array) $q['author__not_in'] ) ) );
+                       $where .= " AND {$wpdb->posts}.post_author NOT IN ($author__not_in) ";
+               } elseif ( ! empty( $q['author__in'] ) ) {
+                       $author__in = implode( ',', array_map( 'absint', array_unique( (array) $q['author__in'] ) ) );
+                       $where .= " AND {$wpdb->posts}.post_author IN ($author__in) ";
                }
 
                // Author stuff for nice URLs
@@ -2242,7 +2937,7 @@ class WP_Query {
                                if ( $q['author_name'][ count($q['author_name'])-1 ] ) {
                                        $q['author_name'] = $q['author_name'][count($q['author_name'])-1]; // no trailing slash
                                } else {
-                                       $q['author_name'] = $q['author_name'][count($q['author_name'])-2]; // there was a trailling slash
+                                       $q['author_name'] = $q['author_name'][count($q['author_name'])-2]; // there was a trailing slash
                                }
                        }
                        $q['author_name'] = sanitize_title_for_query( $q['author_name'] );
@@ -2254,88 +2949,123 @@ class WP_Query {
 
                // MIME-Type stuff for attachment browsing
 
-               if ( isset($q['post_mime_type']) && '' != $q['post_mime_type'] ) {
-                       $table_alias = $post_status_join ? $wpdb->posts : '';
-                       $whichmimetype = wp_post_mime_type_where($q['post_mime_type'], $table_alias);
-               }
+               if ( isset( $q['post_mime_type'] ) && '' != $q['post_mime_type'] )
+                       $whichmimetype = wp_post_mime_type_where( $q['post_mime_type'], $wpdb->posts );
 
                $where .= $search . $whichauthor . $whichmimetype;
 
-               if ( empty($q['order']) || ((strtoupper($q['order']) != 'ASC') && (strtoupper($q['order']) != 'DESC')) )
-                       $q['order'] = 'DESC';
+               if ( ! empty( $this->meta_query->queries ) ) {
+                       $clauses = $this->meta_query->get_sql( 'post', $wpdb->posts, 'ID', $this );
+                       $join   .= $clauses['join'];
+                       $where  .= $clauses['where'];
+               }
+
+               $rand = ( isset( $q['orderby'] ) && 'rand' === $q['orderby'] );
+               if ( ! isset( $q['order'] ) ) {
+                       $q['order'] = $rand ? '' : 'DESC';
+               } else {
+                       $q['order'] = $rand ? '' : $this->parse_order( $q['order'] );
+               }
 
-               // Order by
-               if ( empty($q['orderby']) ) {
-                       $q['orderby'] = "$wpdb->posts.post_date " . $q['order'];
+               // Order by.
+               if ( empty( $q['orderby'] ) ) {
+                       /*
+                        * Boolean false or empty array blanks out ORDER BY,
+                        * while leaving the value unset or otherwise empty sets the default.
+                        */
+                       if ( isset( $q['orderby'] ) && ( is_array( $q['orderby'] ) || false === $q['orderby'] ) ) {
+                               $orderby = '';
+                       } else {
+                               $orderby = "$wpdb->posts.post_date " . $q['order'];
+                       }
                } elseif ( 'none' == $q['orderby'] ) {
-                       $q['orderby'] = '';
+                       $orderby = '';
+               } elseif ( $q['orderby'] == 'post__in' && ! empty( $post__in ) ) {
+                       $orderby = "FIELD( {$wpdb->posts}.ID, $post__in )";
+               } elseif ( $q['orderby'] == 'post_parent__in' && ! empty( $post_parent__in ) ) {
+                       $orderby = "FIELD( {$wpdb->posts}.post_parent, $post_parent__in )";
                } else {
-                       // Used to filter values
-                       $allowed_keys = array('author', 'date', 'title', 'modified', 'menu_order', 'parent', 'ID', 'rand', 'comment_count');
-                       if ( !empty($q['meta_key']) ) {
-                               $allowed_keys[] = $q['meta_key'];
-                               $allowed_keys[] = 'meta_value';
-                               $allowed_keys[] = 'meta_value_num';
-                       }
-                       $q['orderby'] = urldecode($q['orderby']);
-                       $q['orderby'] = addslashes_gpc($q['orderby']);
-                       $orderby_array = explode(' ', $q['orderby']);
-                       $q['orderby'] = '';
-
-                       foreach ( $orderby_array as $i => $orderby ) {
-                               // Only allow certain values for safety
-                               if ( ! in_array($orderby, $allowed_keys) )
-                                       continue;
+                       $orderby_array = array();
+                       if ( is_array( $q['orderby'] ) ) {
+                               foreach ( $q['orderby'] as $_orderby => $order ) {
+                                       $orderby = addslashes_gpc( urldecode( $_orderby ) );
+                                       $parsed  = $this->parse_orderby( $orderby );
 
-                               switch ( $orderby ) {
-                                       case 'menu_order':
-                                               break;
-                                       case 'ID':
-                                               $orderby = "$wpdb->posts.ID";
-                                               break;
-                                       case 'rand':
-                                               $orderby = 'RAND()';
-                                               break;
-                                       case $q['meta_key']:
-                                       case 'meta_value':
-                                               $orderby = "$wpdb->postmeta.meta_value";
-                                               break;
-                                       case 'meta_value_num':
-                                               $orderby = "$wpdb->postmeta.meta_value+0";
-                                               break;
-                                       case 'comment_count':
-                                               $orderby = "$wpdb->posts.comment_count";
-                                               break;
-                                       default:
-                                               $orderby = "$wpdb->posts.post_" . $orderby;
+                                       if ( ! $parsed ) {
+                                               continue;
+                                       }
+
+                                       $orderby_array[] = $parsed . ' ' . $this->parse_order( $order );
                                }
+                               $orderby = implode( ', ', $orderby_array );
 
-                               $q['orderby'] .= (($i == 0) ? '' : ',') . $orderby;
-                       }
+                       } else {
+                               $q['orderby'] = urldecode( $q['orderby'] );
+                               $q['orderby'] = addslashes_gpc( $q['orderby'] );
+
+                               foreach ( explode( ' ', $q['orderby'] ) as $i => $orderby ) {
+                                       $parsed = $this->parse_orderby( $orderby );
+                                       // Only allow certain values for safety.
+                                       if ( ! $parsed ) {
+                                               continue;
+                                       }
 
-                       // append ASC or DESC at the end
-                       if ( !empty($q['orderby']))
-                               $q['orderby'] .= " {$q['order']}";
+                                       $orderby_array[] = $parsed;
+                               }
+                               $orderby = implode( ' ' . $q['order'] . ', ', $orderby_array );
+
+                               if ( empty( $orderby ) ) {
+                                       $orderby = "$wpdb->posts.post_date " . $q['order'];
+                               } elseif ( ! empty( $q['order'] ) ) {
+                                       $orderby .= " {$q['order']}";
+                               }
+                       }
+               }
 
-                       if ( empty($q['orderby']) )
-                               $q['orderby'] = "$wpdb->posts.post_date ".$q['order'];
+               // Order search results by relevance only when another "orderby" is not specified in the query.
+               if ( ! empty( $q['s'] ) ) {
+                       $search_orderby = '';
+                       if ( ! empty( $q['search_orderby_title'] ) && ( empty( $q['orderby'] ) && ! $this->is_feed ) || ( isset( $q['orderby'] ) && 'relevance' === $q['orderby'] ) )
+                               $search_orderby = $this->parse_search_order( $q );
+
+                       /**
+                        * Filter the ORDER BY used when ordering search results.
+                        *
+                        * @since 3.7.0
+                        *
+                        * @param string   $search_orderby The ORDER BY clause.
+                        * @param WP_Query $this           The current WP_Query instance.
+                        */
+                       $search_orderby = apply_filters( 'posts_search_orderby', $search_orderby, $this );
+                       if ( $search_orderby )
+                               $orderby = $orderby ? $search_orderby . ', ' . $orderby : $search_orderby;
                }
 
-               if ( is_array( $post_type ) ) {
+               if ( is_array( $post_type ) && count( $post_type ) > 1 ) {
                        $post_type_cap = 'multiple_post_type';
                } else {
+                       if ( is_array( $post_type ) )
+                               $post_type = reset( $post_type );
                        $post_type_object = get_post_type_object( $post_type );
                        if ( empty( $post_type_object ) )
                                $post_type_cap = $post_type;
                }
 
-               $exclude_post_types = '';
-               $in_search_post_types = get_post_types( array('exclude_from_search' => false) );
-               if ( ! empty( $in_search_post_types ) )
-                       $exclude_post_types .= $wpdb->prepare(" AND $wpdb->posts.post_type IN ('" . join("', '", $in_search_post_types ) . "')");
+               if ( isset( $q['post_password'] ) ) {
+                       $where .= $wpdb->prepare( " AND $wpdb->posts.post_password = %s", $q['post_password'] );
+                       if ( empty( $q['perm'] ) ) {
+                               $q['perm'] = 'readable';
+                       }
+               } elseif ( isset( $q['has_password'] ) ) {
+                       $where .= sprintf( " AND $wpdb->posts.post_password %s ''", $q['has_password'] ? '!=' : '=' );
+               }
 
                if ( 'any' == $post_type ) {
-                       $where .= $exclude_post_types;
+                       $in_search_post_types = get_post_types( array('exclude_from_search' => false) );
+                       if ( empty( $in_search_post_types ) )
+                               $where .= ' AND 1=0 ';
+                       else
+                               $where .= " AND $wpdb->posts.post_type IN ('" . join("', '", $in_search_post_types ) . "')";
                } elseif ( !empty( $post_type ) && is_array( $post_type ) ) {
                        $where .= " AND $wpdb->posts.post_type IN ('" . join("', '", $post_type) . "')";
                } elseif ( ! empty( $post_type ) ) {
@@ -2352,27 +3082,34 @@ class WP_Query {
                        $post_type_object = get_post_type_object ( 'post' );
                }
 
+               $edit_cap = 'edit_post';
+               $read_cap = 'read_post';
+
                if ( ! empty( $post_type_object ) ) {
-                       $edit_cap = $post_type_object->cap->edit_post;
-                       $read_cap = $post_type_object->cap->read_post;
                        $edit_others_cap = $post_type_object->cap->edit_others_posts;
                        $read_private_cap = $post_type_object->cap->read_private_posts;
                } else {
-                       $edit_cap = 'edit_' . $post_type_cap;
-                       $read_cap = 'read_' . $post_type_cap;
                        $edit_others_cap = 'edit_others_' . $post_type_cap . 's';
                        $read_private_cap = 'read_private_' . $post_type_cap . 's';
                }
 
-               if ( isset($q['post_status']) && '' != $q['post_status'] ) {
+               $user_id = get_current_user_id();
+
+               $q_status = array();
+               if ( ! empty( $q['post_status'] ) ) {
                        $statuswheres = array();
-                       $q_status = explode(',', $q['post_status']);
+                       $q_status = $q['post_status'];
+                       if ( ! is_array( $q_status ) )
+                               $q_status = explode(',', $q_status);
                        $r_status = array();
                        $p_status = array();
                        $e_status = array();
-                       if ( $q['post_status'] == 'any' ) {
-                               foreach ( get_post_stati( array('exclude_from_search' => true) ) as $status )
-                                       $e_status[] = "$wpdb->posts.post_status <> '$status'";
+                       if ( in_array( 'any', $q_status ) ) {
+                               foreach ( get_post_stati( array( 'exclude_from_search' => true ) ) as $status ) {
+                                       if ( ! in_array( $status, $q_status ) ) {
+                                               $e_status[] = "$wpdb->posts.post_status <> '$status'";
+                                       }
+                               }
                        } else {
                                foreach ( get_post_stati() as $status ) {
                                        if ( in_array( $status, $q_status ) ) {
@@ -2394,13 +3131,13 @@ class WP_Query {
                        }
                        if ( !empty($r_status) ) {
                                if ( !empty($q['perm'] ) && 'editable' == $q['perm'] && !current_user_can($edit_others_cap) )
-                                       $statuswheres[] = "($wpdb->posts.post_author = $user_ID " .  "AND (" . join( ' OR ', $r_status ) . "))";
+                                       $statuswheres[] = "($wpdb->posts.post_author = $user_id " . "AND (" . join( ' OR ', $r_status ) . "))";
                                else
                                        $statuswheres[] = "(" . join( ' OR ', $r_status ) . ")";
                        }
                        if ( !empty($p_status) ) {
                                if ( !empty($q['perm'] ) && 'readable' == $q['perm'] && !current_user_can($read_private_cap) )
-                                       $statuswheres[] = "($wpdb->posts.post_author = $user_ID " .  "AND (" . join( ' OR ', $p_status ) . "))";
+                                       $statuswheres[] = "($wpdb->posts.post_author = $user_id " . "AND (" . join( ' OR ', $p_status ) . "))";
                                else
                                        $statuswheres[] = "(" . join( ' OR ', $p_status ) . ")";
                        }
@@ -2409,8 +3146,10 @@ class WP_Query {
                                foreach ( $statuswheres as $index => $statuswhere )
                                        $statuswheres[$index] = "($statuswhere OR ($wpdb->posts.post_status = 'inherit' AND " . str_replace($wpdb->posts, 'p2', $statuswhere) . "))";
                        }
-                       foreach ( $statuswheres as $statuswhere )
-                               $where .= " AND $statuswhere";
+                       $where_status = implode( ' OR ', $statuswheres );
+                       if ( ! empty( $where_status ) ) {
+                               $where .= " AND ($where_status)";
+                       }
                } elseif ( !$this->is_singular ) {
                        $where .= " AND ($wpdb->posts.post_status = 'publish'";
 
@@ -2422,7 +3161,7 @@ class WP_Query {
                                $where .= " OR $wpdb->posts.post_status = '$state'";
                        }
 
-                       if ( is_admin() ) {
+                       if ( $this->is_admin ) {
                                // Add protected states that should show in the admin all list.
                                $admin_all_states = get_post_stati( array('protected' => true, 'show_in_admin_all_list' => true) );
                                foreach ( (array) $admin_all_states as $state )
@@ -2433,44 +3172,56 @@ class WP_Query {
                                // Add private states that are limited to viewing by the author of a post or someone who has caps to read private states.
                                $private_states = get_post_stati( array('private' => true) );
                                foreach ( (array) $private_states as $state )
-                                       $where .= current_user_can( $read_private_cap ) ? " OR $wpdb->posts.post_status = '$state'" : " OR $wpdb->posts.post_author = $user_ID AND $wpdb->posts.post_status = '$state'";
+                                       $where .= current_user_can( $read_private_cap ) ? " OR $wpdb->posts.post_status = '$state'" : " OR $wpdb->posts.post_author = $user_id AND $wpdb->posts.post_status = '$state'";
                        }
 
                        $where .= ')';
                }
 
-               if ( !empty( $q['meta_query'] ) ) {
-                       $clauses = call_user_func_array( '_get_meta_sql', array( $q['meta_query'], 'post', $wpdb->posts, 'ID', &$this) );
-                       $join .= $clauses['join'];
-                       $where .= $clauses['where'];
-               }
-
-               // Apply filters on where and join prior to paging so that any
-               // manipulations to them are reflected in the paging by day queries.
+               /*
+                * Apply filters on where and join prior to paging so that any
+                * manipulations to them are reflected in the paging by day queries.
+                */
                if ( !$q['suppress_filters'] ) {
-                       $where = apply_filters_ref_array('posts_where', array( $where, &$this ) );
-                       $join = apply_filters_ref_array('posts_join', array( $join, &$this ) );
+                       /**
+                        * Filter the WHERE clause of the query.
+                        *
+                        * @since 1.5.0
+                        *
+                        * @param string   $where The WHERE clause of the query.
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       $where = apply_filters_ref_array( 'posts_where', array( $where, &$this ) );
+
+                       /**
+                        * Filter the JOIN clause of the query.
+                        *
+                        * @since 1.5.0
+                        *
+                        * @param string   $where The JOIN clause of the query.
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       $join = apply_filters_ref_array( 'posts_join', array( $join, &$this ) );
                }
 
                // Paging
                if ( empty($q['nopaging']) && !$this->is_singular ) {
                        $page = absint($q['paged']);
-                       if ( empty($page) )
+                       if ( !$page )
                                $page = 1;
 
-                       if ( empty($q['offset']) ) {
-                               $pgstrt = '';
-                               $pgstrt = ($page - 1) * $q['posts_per_page'] . ', ';
-                               $limits = 'LIMIT ' . $pgstrt . $q['posts_per_page'];
-                       } else { // we're ignoring $page and using 'offset'
-                               $q['offset'] = absint($q['offset']);
+                       // If 'offset' is provided, it takes precedence over 'paged'.
+                       if ( isset( $q['offset'] ) && is_numeric( $q['offset'] ) ) {
+                               $q['offset'] = absint( $q['offset'] );
                                $pgstrt = $q['offset'] . ', ';
-                               $limits = 'LIMIT ' . $pgstrt . $q['posts_per_page'];
+                       } else {
+                               $pgstrt = absint( ( $page - 1 ) * $q['posts_per_page'] ) . ', ';
                        }
+                       $limits = 'LIMIT ' . $pgstrt . $q['posts_per_page'];
                }
 
                // Comments feeds
-               if ( $this->is_comment_feed && ( $this->is_archive || $this->is_search || !$this->is_singular ) ) {
+               if ( $this->is_comment_feed && ! $this->is_singular ) {
                        if ( $this->is_archive || $this->is_search ) {
                                $cjoin = "JOIN $wpdb->posts ON ($wpdb->comments.comment_post_ID = $wpdb->posts.ID) $join ";
                                $cwhere = "WHERE comment_approved = '1' $where";
@@ -2482,16 +3233,62 @@ class WP_Query {
                        }
 
                        if ( !$q['suppress_filters'] ) {
-                               $cjoin = apply_filters_ref_array('comment_feed_join', array( $cjoin, &$this ) );
-                               $cwhere = apply_filters_ref_array('comment_feed_where', array( $cwhere, &$this ) );
-                               $cgroupby = apply_filters_ref_array('comment_feed_groupby', array( $cgroupby, &$this ) );
-                               $corderby = apply_filters_ref_array('comment_feed_orderby', array( 'comment_date_gmt DESC', &$this ) );
-                               $climits = apply_filters_ref_array('comment_feed_limits', array( 'LIMIT ' . get_option('posts_per_rss'), &$this ) );
+                               /**
+                                * Filter the JOIN clause of the comments feed query before sending.
+                                *
+                                * @since 2.2.0
+                                *
+                                * @param string   $cjoin The JOIN clause of the query.
+                                * @param WP_Query &$this The WP_Query instance (passed by reference).
+                                */
+                               $cjoin = apply_filters_ref_array( 'comment_feed_join', array( $cjoin, &$this ) );
+
+                               /**
+                                * Filter the WHERE clause of the comments feed query before sending.
+                                *
+                                * @since 2.2.0
+                                *
+                                * @param string   $cwhere The WHERE clause of the query.
+                                * @param WP_Query &$this  The WP_Query instance (passed by reference).
+                                */
+                               $cwhere = apply_filters_ref_array( 'comment_feed_where', array( $cwhere, &$this ) );
+
+                               /**
+                                * Filter the GROUP BY clause of the comments feed query before sending.
+                                *
+                                * @since 2.2.0
+                                *
+                                * @param string   $cgroupby The GROUP BY clause of the query.
+                                * @param WP_Query &$this    The WP_Query instance (passed by reference).
+                                */
+                               $cgroupby = apply_filters_ref_array( 'comment_feed_groupby', array( $cgroupby, &$this ) );
+
+                               /**
+                                * Filter the ORDER BY clause of the comments feed query before sending.
+                                *
+                                * @since 2.8.0
+                                *
+                                * @param string   $corderby The ORDER BY clause of the query.
+                                * @param WP_Query &$this    The WP_Query instance (passed by reference).
+                                */
+                               $corderby = apply_filters_ref_array( 'comment_feed_orderby', array( 'comment_date_gmt DESC', &$this ) );
+
+                               /**
+                                * Filter the LIMIT clause of the comments feed query before sending.
+                                *
+                                * @since 2.8.0
+                                *
+                                * @param string   $climits The JOIN clause of the query.
+                                * @param WP_Query &$this   The WP_Query instance (passed by reference).
+                                */
+                               $climits = apply_filters_ref_array( 'comment_feed_limits', array( 'LIMIT ' . get_option('posts_per_rss'), &$this ) );
                        }
                        $cgroupby = ( ! empty( $cgroupby ) ) ? 'GROUP BY ' . $cgroupby : '';
                        $corderby = ( ! empty( $corderby ) ) ? 'ORDER BY ' . $corderby : '';
 
-                       $this->comments = (array) $wpdb->get_results("SELECT $distinct $wpdb->comments.* FROM $wpdb->comments $cjoin $cwhere $cgroupby $corderby $climits");
+                       $comments = (array) $wpdb->get_results("SELECT $distinct $wpdb->comments.* FROM $wpdb->comments $cjoin $cwhere $cgroupby $corderby $climits");
+                       // Convert to WP_Comment
+                       $this->comments = array_map( 'get_comment', $comments );
                        $this->comment_count = count($this->comments);
 
                        $post_ids = array();
@@ -2507,44 +3304,231 @@ class WP_Query {
                                $where = "AND 0";
                }
 
-               $orderby = $q['orderby'];
-
                $pieces = array( 'where', 'groupby', 'join', 'orderby', 'distinct', 'fields', 'limits' );
 
-               // Apply post-paging filters on where and join.  Only plugins that
-               // manipulate paging queries should use these hooks.
+               /*
+                * Apply post-paging filters on where and join. Only plugins that
+                * manipulate paging queries should use these hooks.
+                */
                if ( !$q['suppress_filters'] ) {
-                       $where          = apply_filters_ref_array( 'posts_where_paged', array( $where, &$this ) );
-                       $groupby        = apply_filters_ref_array( 'posts_groupby',             array( $groupby, &$this ) );
-                       $join           = apply_filters_ref_array( 'posts_join_paged',  array( $join, &$this ) );
-                       $orderby        = apply_filters_ref_array( 'posts_orderby',             array( $orderby, &$this ) );
-                       $distinct       = apply_filters_ref_array( 'posts_distinct',    array( $distinct, &$this ) );
-                       $limits         = apply_filters_ref_array( 'post_limits',               array( $limits, &$this ) );
-                       $fields         = apply_filters_ref_array( 'posts_fields',              array( $fields, &$this ) );
-
-                       // Filter all clauses at once, for convenience
+                       /**
+                        * Filter the WHERE clause of the query.
+                        *
+                        * Specifically for manipulating paging queries.
+                        *
+                        * @since 1.5.0
+                        *
+                        * @param string   $where The WHERE clause of the query.
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       $where = apply_filters_ref_array( 'posts_where_paged', array( $where, &$this ) );
+
+                       /**
+                        * Filter the GROUP BY clause of the query.
+                        *
+                        * @since 2.0.0
+                        *
+                        * @param string   $groupby The GROUP BY clause of the query.
+                        * @param WP_Query &$this   The WP_Query instance (passed by reference).
+                        */
+                       $groupby = apply_filters_ref_array( 'posts_groupby', array( $groupby, &$this ) );
+
+                       /**
+                        * Filter the JOIN clause of the query.
+                        *
+                        * Specifically for manipulating paging queries.
+                        *
+                        * @since 1.5.0
+                        *
+                        * @param string   $join  The JOIN clause of the query.
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       $join = apply_filters_ref_array( 'posts_join_paged', array( $join, &$this ) );
+
+                       /**
+                        * Filter the ORDER BY clause of the query.
+                        *
+                        * @since 1.5.1
+                        *
+                        * @param string   $orderby The ORDER BY clause of the query.
+                        * @param WP_Query &$this   The WP_Query instance (passed by reference).
+                        */
+                       $orderby = apply_filters_ref_array( 'posts_orderby', array( $orderby, &$this ) );
+
+                       /**
+                        * Filter the DISTINCT clause of the query.
+                        *
+                        * @since 2.1.0
+                        *
+                        * @param string   $distinct The DISTINCT clause of the query.
+                        * @param WP_Query &$this    The WP_Query instance (passed by reference).
+                        */
+                       $distinct = apply_filters_ref_array( 'posts_distinct', array( $distinct, &$this ) );
+
+                       /**
+                        * Filter the LIMIT clause of the query.
+                        *
+                        * @since 2.1.0
+                        *
+                        * @param string   $limits The LIMIT clause of the query.
+                        * @param WP_Query &$this  The WP_Query instance (passed by reference).
+                        */
+                       $limits = apply_filters_ref_array( 'post_limits', array( $limits, &$this ) );
+
+                       /**
+                        * Filter the SELECT clause of the query.
+                        *
+                        * @since 2.1.0
+                        *
+                        * @param string   $fields The SELECT clause of the query.
+                        * @param WP_Query &$this  The WP_Query instance (passed by reference).
+                        */
+                       $fields = apply_filters_ref_array( 'posts_fields', array( $fields, &$this ) );
+
+                       /**
+                        * Filter all query clauses at once, for convenience.
+                        *
+                        * Covers the WHERE, GROUP BY, JOIN, ORDER BY, DISTINCT,
+                        * fields (SELECT), and LIMITS clauses.
+                        *
+                        * @since 3.1.0
+                        *
+                        * @param array    $clauses The list of clauses for the query.
+                        * @param WP_Query &$this   The WP_Query instance (passed by reference).
+                        */
                        $clauses = (array) apply_filters_ref_array( 'posts_clauses', array( compact( $pieces ), &$this ) );
-                       foreach ( $pieces as $piece )
-                               $$piece = isset( $clauses[ $piece ] ) ? $clauses[ $piece ] : '';
+
+                       $where = isset( $clauses[ 'where' ] ) ? $clauses[ 'where' ] : '';
+                       $groupby = isset( $clauses[ 'groupby' ] ) ? $clauses[ 'groupby' ] : '';
+                       $join = isset( $clauses[ 'join' ] ) ? $clauses[ 'join' ] : '';
+                       $orderby = isset( $clauses[ 'orderby' ] ) ? $clauses[ 'orderby' ] : '';
+                       $distinct = isset( $clauses[ 'distinct' ] ) ? $clauses[ 'distinct' ] : '';
+                       $fields = isset( $clauses[ 'fields' ] ) ? $clauses[ 'fields' ] : '';
+                       $limits = isset( $clauses[ 'limits' ] ) ? $clauses[ 'limits' ] : '';
                }
 
-               // Announce current selection parameters.  For use by caching plugins.
+               /**
+                * Fires to announce the query's current selection parameters.
+                *
+                * For use by caching plugins.
+                *
+                * @since 2.3.0
+                *
+                * @param string $selection The assembled selection query.
+                */
                do_action( 'posts_selection', $where . $groupby . $orderby . $limits . $join );
 
-               // Filter again for the benefit of caching plugins.  Regular plugins should use the hooks above.
+               /*
+                * Filter again for the benefit of caching plugins.
+                * Regular plugins should use the hooks above.
+                */
                if ( !$q['suppress_filters'] ) {
-                       $where          = apply_filters_ref_array( 'posts_where_request',               array( $where, &$this ) );
-                       $groupby        = apply_filters_ref_array( 'posts_groupby_request',             array( $groupby, &$this ) );
-                       $join           = apply_filters_ref_array( 'posts_join_request',                array( $join, &$this ) );
-                       $orderby        = apply_filters_ref_array( 'posts_orderby_request',             array( $orderby, &$this ) );
-                       $distinct       = apply_filters_ref_array( 'posts_distinct_request',    array( $distinct, &$this ) );
-                       $fields         = apply_filters_ref_array( 'posts_fields_request',              array( $fields, &$this ) );
-                       $limits         = apply_filters_ref_array( 'post_limits_request',               array( $limits, &$this ) );
-
-                       // Filter all clauses at once, for convenience
+                       /**
+                        * Filter the WHERE clause of the query.
+                        *
+                        * For use by caching plugins.
+                        *
+                        * @since 2.5.0
+                        *
+                        * @param string   $where The WHERE clause of the query.
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       $where = apply_filters_ref_array( 'posts_where_request', array( $where, &$this ) );
+
+                       /**
+                        * Filter the GROUP BY clause of the query.
+                        *
+                        * For use by caching plugins.
+                        *
+                        * @since 2.5.0
+                        *
+                        * @param string   $groupby The GROUP BY clause of the query.
+                        * @param WP_Query &$this   The WP_Query instance (passed by reference).
+                        */
+                       $groupby = apply_filters_ref_array( 'posts_groupby_request', array( $groupby, &$this ) );
+
+                       /**
+                        * Filter the JOIN clause of the query.
+                        *
+                        * For use by caching plugins.
+                        *
+                        * @since 2.5.0
+                        *
+                        * @param string   $join  The JOIN clause of the query.
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       $join = apply_filters_ref_array( 'posts_join_request', array( $join, &$this ) );
+
+                       /**
+                        * Filter the ORDER BY clause of the query.
+                        *
+                        * For use by caching plugins.
+                        *
+                        * @since 2.5.0
+                        *
+                        * @param string   $orderby The ORDER BY clause of the query.
+                        * @param WP_Query &$this   The WP_Query instance (passed by reference).
+                        */
+                       $orderby = apply_filters_ref_array( 'posts_orderby_request', array( $orderby, &$this ) );
+
+                       /**
+                        * Filter the DISTINCT clause of the query.
+                        *
+                        * For use by caching plugins.
+                        *
+                        * @since 2.5.0
+                        *
+                        * @param string   $distinct The DISTINCT clause of the query.
+                        * @param WP_Query &$this    The WP_Query instance (passed by reference).
+                        */
+                       $distinct = apply_filters_ref_array( 'posts_distinct_request', array( $distinct, &$this ) );
+
+                       /**
+                        * Filter the SELECT clause of the query.
+                        *
+                        * For use by caching plugins.
+                        *
+                        * @since 2.5.0
+                        *
+                        * @param string   $fields The SELECT clause of the query.
+                        * @param WP_Query &$this  The WP_Query instance (passed by reference).
+                        */
+                       $fields = apply_filters_ref_array( 'posts_fields_request', array( $fields, &$this ) );
+
+                       /**
+                        * Filter the LIMIT clause of the query.
+                        *
+                        * For use by caching plugins.
+                        *
+                        * @since 2.5.0
+                        *
+                        * @param string   $limits The LIMIT clause of the query.
+                        * @param WP_Query &$this  The WP_Query instance (passed by reference).
+                        */
+                       $limits = apply_filters_ref_array( 'post_limits_request', array( $limits, &$this ) );
+
+                       /**
+                        * Filter all query clauses at once, for convenience.
+                        *
+                        * For use by caching plugins.
+                        *
+                        * Covers the WHERE, GROUP BY, JOIN, ORDER BY, DISTINCT,
+                        * fields (SELECT), and LIMITS clauses.
+                        *
+                        * @since 3.1.0
+                        *
+                        * @param array    $pieces The pieces of the query.
+                        * @param WP_Query &$this  The WP_Query instance (passed by reference).
+                        */
                        $clauses = (array) apply_filters_ref_array( 'posts_clauses_request', array( compact( $pieces ), &$this ) );
-                       foreach ( $pieces as $piece )
-                               $$piece = isset( $clauses[ $piece ] ) ? $clauses[ $piece ] : '';
+
+                       $where = isset( $clauses[ 'where' ] ) ? $clauses[ 'where' ] : '';
+                       $groupby = isset( $clauses[ 'groupby' ] ) ? $clauses[ 'groupby' ] : '';
+                       $join = isset( $clauses[ 'join' ] ) ? $clauses[ 'join' ] : '';
+                       $orderby = isset( $clauses[ 'orderby' ] ) ? $clauses[ 'orderby' ] : '';
+                       $distinct = isset( $clauses[ 'distinct' ] ) ? $clauses[ 'distinct' ] : '';
+                       $fields = isset( $clauses[ 'fields' ] ) ? $clauses[ 'fields' ] : '';
+                       $limits = isset( $clauses[ 'limits' ] ) ? $clauses[ 'limits' ] : '';
                }
 
                if ( ! empty($groupby) )
@@ -2556,58 +3540,150 @@ class WP_Query {
                if ( !$q['no_found_rows'] && !empty($limits) )
                        $found_rows = 'SQL_CALC_FOUND_ROWS';
 
-               $this->request = " SELECT $found_rows $distinct $fields FROM $wpdb->posts $join WHERE 1=1 $where $groupby $orderby $limits";
-               if ( !$q['suppress_filters'] )
-                       $this->request = apply_filters_ref_array('posts_request', array( $this->request, &$this ) );
+               $this->request = $old_request = "SELECT $found_rows $distinct $fields FROM $wpdb->posts $join WHERE 1=1 $where $groupby $orderby $limits";
+
+               if ( !$q['suppress_filters'] ) {
+                       /**
+                        * Filter the completed SQL query before sending.
+                        *
+                        * @since 2.0.0
+                        *
+                        * @param array    $request The complete SQL query.
+                        * @param WP_Query &$this   The WP_Query instance (passed by reference).
+                        */
+                       $this->request = apply_filters_ref_array( 'posts_request', array( $this->request, &$this ) );
+               }
 
                if ( 'ids' == $q['fields'] ) {
-                       $this->posts = $wpdb->get_col($this->request);
+                       $this->posts = $wpdb->get_col( $this->request );
+                       $this->posts = array_map( 'intval', $this->posts );
+                       $this->post_count = count( $this->posts );
+                       $this->set_found_posts( $q, $limits );
 
                        return $this->posts;
                }
 
                if ( 'id=>parent' == $q['fields'] ) {
-                       $this->posts = $wpdb->get_results($this->request);
+                       $this->posts = $wpdb->get_results( $this->request );
+                       $this->post_count = count( $this->posts );
+                       $this->set_found_posts( $q, $limits );
 
                        $r = array();
-                       foreach ( $this->posts as $post )
-                               $r[ $post->ID ] = $post->post_parent;
+                       foreach ( $this->posts as $key => $post ) {
+                               $this->posts[ $key ]->ID = (int) $post->ID;
+                               $this->posts[ $key ]->post_parent = (int) $post->post_parent;
+
+                               $r[ (int) $post->ID ] = (int) $post->post_parent;
+                       }
 
                        return $r;
                }
 
-               $this->posts = $wpdb->get_results($this->request);
+               $split_the_query = ( $old_request == $this->request && "$wpdb->posts.*" == $fields && !empty( $limits ) && $q['posts_per_page'] < 500 );
+
+               /**
+                * Filter whether to split the query.
+                *
+                * Splitting the query will cause it to fetch just the IDs of the found posts
+                * (and then individually fetch each post by ID), rather than fetching every
+                * complete row at once. One massive result vs. many small results.
+                *
+                * @since 3.4.0
+                *
+                * @param bool     $split_the_query Whether or not to split the query.
+                * @param WP_Query $this            The WP_Query instance.
+                */
+               $split_the_query = apply_filters( 'split_the_query', $split_the_query, $this );
+
+               if ( $split_the_query ) {
+                       // First get the IDs and then fill in the objects
+
+                       $this->request = "SELECT $found_rows $distinct $wpdb->posts.ID FROM $wpdb->posts $join WHERE 1=1 $where $groupby $orderby $limits";
+
+                       /**
+                        * Filter the Post IDs SQL request before sending.
+                        *
+                        * @since 3.4.0
+                        *
+                        * @param string   $request The post ID request.
+                        * @param WP_Query $this    The WP_Query instance.
+                        */
+                       $this->request = apply_filters( 'posts_request_ids', $this->request, $this );
+
+                       $ids = $wpdb->get_col( $this->request );
+
+                       if ( $ids ) {
+                               $this->posts = $ids;
+                               $this->set_found_posts( $q, $limits );
+                               _prime_post_caches( $ids, $q['update_post_term_cache'], $q['update_post_meta_cache'] );
+                       } else {
+                               $this->posts = array();
+                       }
+               } else {
+                       $this->posts = $wpdb->get_results( $this->request );
+                       $this->set_found_posts( $q, $limits );
+               }
+
+               // Convert to WP_Post objects
+               if ( $this->posts )
+                       $this->posts = array_map( 'get_post', $this->posts );
+
 
-               // Raw results filter.  Prior to status checks.
-               if ( !$q['suppress_filters'] )
-                       $this->posts = apply_filters_ref_array('posts_results', array( $this->posts, &$this ) );
+               if ( $q['update_post_term_cache'] ) {
+                       add_filter( 'get_term_metadata', array( $this, 'lazyload_term_meta' ), 10, 2 );
+               }
+
+               if ( ! $q['suppress_filters'] ) {
+                       /**
+                        * Filter the raw post results array, prior to status checks.
+                        *
+                        * @since 2.3.0
+                        *
+                        * @param array    $posts The post results array.
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       $this->posts = apply_filters_ref_array( 'posts_results', array( $this->posts, &$this ) );
+               }
 
                if ( !empty($this->posts) && $this->is_comment_feed && $this->is_singular ) {
-                       $cjoin = apply_filters_ref_array('comment_feed_join', array( '', &$this ) );
-                       $cwhere = apply_filters_ref_array('comment_feed_where', array( "WHERE comment_post_ID = '{$this->posts[0]->ID}' AND comment_approved = '1'", &$this ) );
-                       $cgroupby = apply_filters_ref_array('comment_feed_groupby', array( '', &$this ) );
+                       /** This filter is documented in wp-includes/query.php */
+                       $cjoin = apply_filters_ref_array( 'comment_feed_join', array( '', &$this ) );
+
+                       /** This filter is documented in wp-includes/query.php */
+                       $cwhere = apply_filters_ref_array( 'comment_feed_where', array( "WHERE comment_post_ID = '{$this->posts[0]->ID}' AND comment_approved = '1'", &$this ) );
+
+                       /** This filter is documented in wp-includes/query.php */
+                       $cgroupby = apply_filters_ref_array( 'comment_feed_groupby', array( '', &$this ) );
                        $cgroupby = ( ! empty( $cgroupby ) ) ? 'GROUP BY ' . $cgroupby : '';
-                       $corderby = apply_filters_ref_array('comment_feed_orderby', array( 'comment_date_gmt DESC', &$this ) );
+
+                       /** This filter is documented in wp-includes/query.php */
+                       $corderby = apply_filters_ref_array( 'comment_feed_orderby', array( 'comment_date_gmt DESC', &$this ) );
                        $corderby = ( ! empty( $corderby ) ) ? 'ORDER BY ' . $corderby : '';
-                       $climits = apply_filters_ref_array('comment_feed_limits', array( 'LIMIT ' . get_option('posts_per_rss'), &$this ) );
+
+                       /** This filter is documented in wp-includes/query.php */
+                       $climits = apply_filters_ref_array( 'comment_feed_limits', array( 'LIMIT ' . get_option('posts_per_rss'), &$this ) );
+
                        $comments_request = "SELECT $wpdb->comments.* FROM $wpdb->comments $cjoin $cwhere $cgroupby $corderby $climits";
-                       $this->comments = $wpdb->get_results($comments_request);
+                       $comments = $wpdb->get_results($comments_request);
+                       // Convert to WP_Comment
+                       $this->comments = array_map( 'get_comment', $comments );
                        $this->comment_count = count($this->comments);
                }
 
-               if ( !$q['no_found_rows'] && !empty($limits) ) {
-                       $found_posts_query = apply_filters_ref_array( 'found_posts_query', array( 'SELECT FOUND_ROWS()', &$this ) );
-                       $this->found_posts = $wpdb->get_var( $found_posts_query );
-                       $this->found_posts = apply_filters_ref_array( 'found_posts', array( $this->found_posts, &$this ) );
-                       $this->max_num_pages = ceil($this->found_posts / $q['posts_per_page']);
-               }
-
                // Check post status to determine if post should be displayed.
                if ( !empty($this->posts) && ($this->is_single || $this->is_page) ) {
                        $status = get_post_status($this->posts[0]);
+                       if ( 'attachment' === $this->posts[0]->post_type && 0 === (int) $this->posts[0]->post_parent ) {
+                               $this->is_page = false;
+                               $this->is_single = true;
+                               $this->is_attachment = true;
+                       }
                        $post_status_obj = get_post_status_object($status);
                        //$type = get_post_type($this->posts[0]);
-                       if ( !$post_status_obj->public ) {
+
+                       // If the post_status was specifically requested, let it pass through.
+                       if ( !$post_status_obj->public && ! in_array( $status, $q_status ) ) {
+
                                if ( ! is_user_logged_in() ) {
                                        // User must be logged in to view unpublished posts.
                                        $this->posts = array();
@@ -2630,8 +3706,17 @@ class WP_Query {
                                }
                        }
 
-                       if ( $this->is_preview && current_user_can( $edit_cap, $this->posts[0]->ID ) )
-                               $this->posts[0] = apply_filters_ref_array('the_preview', array( $this->posts[0], &$this ));
+                       if ( $this->is_preview && $this->posts && current_user_can( $edit_cap, $this->posts[0]->ID ) ) {
+                               /**
+                                * Filter the single post for preview mode.
+                                *
+                                * @since 2.7.0
+                                *
+                                * @param WP_Post  $post_preview  The Post object.
+                                * @param WP_Query &$this         The WP_Query instance (passed by reference).
+                                */
+                               $this->posts[0] = get_post( apply_filters_ref_array( 'the_preview', array( $this->posts[0], &$this ) ) );
+                       }
                }
 
                // Put sticky posts at the top of the posts array
@@ -2647,7 +3732,7 @@ class WP_Query {
                                        array_splice($this->posts, $i, 1);
                                        // Move to front, after other stickies
                                        array_splice($this->posts, $sticky_offset, 0, array($sticky_post));
-                                       // Increment the sticky offset.  The next sticky will be placed at this offset.
+                                       // Increment the sticky offset. The next sticky will be placed at this offset.
                                        $sticky_offset++;
                                        // Remove post from sticky posts array
                                        $offset = array_search($sticky_post->ID, $sticky_posts);
@@ -2661,58 +3746,111 @@ class WP_Query {
 
                        // Fetch sticky posts that weren't in the query results
                        if ( !empty($sticky_posts) ) {
-                               $stickies__in = implode(',', array_map( 'absint', $sticky_posts ));
-                               // honor post type(s) if not set to any
-                               $stickies_where = '';
-                               if ( 'any' != $post_type && '' != $post_type ) {
-                                       if ( is_array( $post_type ) ) {
-                                               $post_types = join( "', '", $post_type );
-                                       } else {
-                                               $post_types = $post_type;
-                                       }
-                                       $stickies_where = "AND $wpdb->posts.post_type IN ('" . $post_types . "')";
-                               }
+                               $stickies = get_posts( array(
+                                       'post__in' => $sticky_posts,
+                                       'post_type' => $post_type,
+                                       'post_status' => 'publish',
+                                       'nopaging' => true
+                               ) );
 
-                               $stickies = $wpdb->get_results( "SELECT * FROM $wpdb->posts WHERE $wpdb->posts.ID IN ($stickies__in) $stickies_where" );
                                foreach ( $stickies as $sticky_post ) {
-                                       // Ignore sticky posts the current user cannot read or are not published.
-                                       if ( 'publish' != $sticky_post->post_status )
-                                               continue;
-                                       array_splice($this->posts, $sticky_offset, 0, array($sticky_post));
+                                       array_splice( $this->posts, $sticky_offset, 0, array( $sticky_post ) );
                                        $sticky_offset++;
                                }
                        }
                }
 
-               if ( !$q['suppress_filters'] )
-                       $this->posts = apply_filters_ref_array('the_posts', array( $this->posts, &$this ) );
-
-               $this->post_count = count($this->posts);
+               // If comments have been fetched as part of the query, make sure comment meta lazy-loading is set up.
+               if ( ! empty( $this->comments ) ) {
+                       add_filter( 'get_comment_metadata', array( $this, 'lazyload_comment_meta' ), 10, 2 );
+               }
 
-               // Sanitize before caching so it'll only get done once
-               for ( $i = 0; $i < $this->post_count; $i++ ) {
-                       $this->posts[$i] = sanitize_post($this->posts[$i], 'raw');
+               if ( ! $q['suppress_filters'] ) {
+                       /**
+                        * Filter the array of retrieved posts after they've been fetched and
+                        * internally processed.
+                        *
+                        * @since 1.5.0
+                        *
+                        * @param array    $posts The array of retrieved posts.
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       $this->posts = apply_filters_ref_array( 'the_posts', array( $this->posts, &$this ) );
                }
 
-               if ( $q['cache_results'] )
-                       update_post_caches($this->posts, $post_type, $q['update_post_term_cache'], $q['update_post_meta_cache']);
+               // Ensure that any posts added/modified via one of the filters above are
+               // of the type WP_Post and are filtered.
+               if ( $this->posts ) {
+                       $this->post_count = count( $this->posts );
 
-               if ( $this->post_count > 0 ) {
-                       $this->post = $this->posts[0];
+                       $this->posts = array_map( 'get_post', $this->posts );
+
+                       if ( $q['cache_results'] )
+                               update_post_caches($this->posts, $post_type, $q['update_post_term_cache'], $q['update_post_meta_cache']);
+
+                       $this->post = reset( $this->posts );
+               } else {
+                       $this->post_count = 0;
+                       $this->posts = array();
                }
 
                return $this->posts;
        }
 
+       /**
+        * Set up the amount of found posts and the number of pages (if limit clause was used)
+        * for the current query.
+        *
+        * @since 3.5.0
+        * @access private
+        *
+        * @global wpdb $wpdb WordPress database abstraction object.
+        */
+       private function set_found_posts( $q, $limits ) {
+               global $wpdb;
+
+               // Bail if posts is an empty array. Continue if posts is an empty string,
+               // null, or false to accommodate caching plugins that fill posts later.
+               if ( $q['no_found_rows'] || ( is_array( $this->posts ) && ! $this->posts ) )
+                       return;
+
+               if ( ! empty( $limits ) ) {
+                       /**
+                        * Filter the query to run for retrieving the found posts.
+                        *
+                        * @since 2.1.0
+                        *
+                        * @param string   $found_posts The query to run to find the found posts.
+                        * @param WP_Query &$this       The WP_Query instance (passed by reference).
+                        */
+                       $this->found_posts = $wpdb->get_var( apply_filters_ref_array( 'found_posts_query', array( 'SELECT FOUND_ROWS()', &$this ) ) );
+               } else {
+                       $this->found_posts = count( $this->posts );
+               }
+
+               /**
+                * Filter the number of found posts for the query.
+                *
+                * @since 2.1.0
+                *
+                * @param int      $found_posts The number of posts found.
+                * @param WP_Query &$this       The WP_Query instance (passed by reference).
+                */
+               $this->found_posts = apply_filters_ref_array( 'found_posts', array( $this->found_posts, &$this ) );
+
+               if ( ! empty( $limits ) )
+                       $this->max_num_pages = ceil( $this->found_posts / $q['posts_per_page'] );
+       }
+
        /**
         * Set up the next post and iterate current post index.
         *
         * @since 1.5.0
         * @access public
         *
-        * @return object Next post.
+        * @return WP_Post Next post.
         */
-       function next_post() {
+       public function next_post() {
 
                $this->current_post++;
 
@@ -2728,18 +3866,25 @@ class WP_Query {
         *
         * @since 1.5.0
         * @access public
-        * @uses $post
-        * @uses do_action_ref_array() Calls 'loop_start' if loop has just started
+        *
+        * @global WP_Post $post
         */
-       function the_post() {
+       public function the_post() {
                global $post;
                $this->in_the_loop = true;
 
                if ( $this->current_post == -1 ) // loop has just started
-                       do_action_ref_array('loop_start', array(&$this));
+                       /**
+                        * Fires once the loop is started.
+                        *
+                        * @since 2.0.0
+                        *
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       do_action_ref_array( 'loop_start', array( &$this ) );
 
                $post = $this->next_post();
-               setup_postdata($post);
+               $this->setup_postdata( $post );
        }
 
        /**
@@ -2749,15 +3894,21 @@ class WP_Query {
         *
         * @since 1.5.0
         * @access public
-        * @uses do_action_ref_array() Calls 'loop_end' if loop is ended
         *
         * @return bool True if posts are available, false if end of loop.
         */
-       function have_posts() {
+       public function have_posts() {
                if ( $this->current_post + 1 < $this->post_count ) {
                        return true;
                } elseif ( $this->current_post + 1 == $this->post_count && $this->post_count > 0 ) {
-                       do_action_ref_array('loop_end', array(&$this));
+                       /**
+                        * Fires once the loop has ended.
+                        *
+                        * @since 2.0.0
+                        *
+                        * @param WP_Query &$this The WP_Query instance (passed by reference).
+                        */
+                       do_action_ref_array( 'loop_end', array( &$this ) );
                        // Do some cleaning up after the loop
                        $this->rewind_posts();
                }
@@ -2772,7 +3923,7 @@ class WP_Query {
         * @since 1.5.0
         * @access public
         */
-       function rewind_posts() {
+       public function rewind_posts() {
                $this->current_post = -1;
                if ( $this->post_count > 0 ) {
                        $this->post = $this->posts[0];
@@ -2780,14 +3931,14 @@ class WP_Query {
        }
 
        /**
-        * Iterate current comment index and return comment object.
+        * Iterate current comment index and return WP_Comment object.
         *
         * @since 2.2.0
         * @access public
         *
-        * @return object Comment object.
+        * @return WP_Comment Comment object.
         */
-       function next_comment() {
+       public function next_comment() {
                $this->current_comment++;
 
                $this->comment = $this->comments[$this->current_comment];
@@ -2799,16 +3950,20 @@ class WP_Query {
         *
         * @since 2.2.0
         * @access public
-        * @global object $comment Current comment.
-        * @uses do_action() Calls 'comment_loop_start' hook when first comment is processed.
+        * @global WP_Comment $comment Current comment.
         */
-       function the_comment() {
+       public function the_comment() {
                global $comment;
 
                $comment = $this->next_comment();
 
                if ( $this->current_comment == 0 ) {
-                       do_action('comment_loop_start');
+                       /**
+                        * Fires once the comment loop is started.
+                        *
+                        * @since 2.2.0
+                        */
+                       do_action( 'comment_loop_start' );
                }
        }
 
@@ -2822,7 +3977,7 @@ class WP_Query {
         *
         * @return bool True, if more comments. False, if no more posts.
         */
-       function have_comments() {
+       public function have_comments() {
                if ( $this->current_comment + 1 < $this->comment_count ) {
                        return true;
                } elseif ( $this->current_comment + 1 == $this->comment_count ) {
@@ -2838,7 +3993,7 @@ class WP_Query {
         * @since 2.2.0
         * @access public
         */
-       function rewind_comments() {
+       public function rewind_comments() {
                $this->current_comment = -1;
                if ( $this->comment_count > 0 ) {
                        $this->comment = $this->comments[0];
@@ -2854,7 +4009,7 @@ class WP_Query {
         * @param string $query URL query string.
         * @return array List of posts.
         */
-       function &query( $query ) {
+       public function query( $query ) {
                $this->init();
                $this->query = $this->query_vars = wp_parse_args( $query );
                return $this->get_posts();
@@ -2872,34 +4027,62 @@ class WP_Query {
         *
         * @return object
         */
-       function get_queried_object() {
+       public function get_queried_object() {
                if ( isset($this->queried_object) )
                        return $this->queried_object;
 
-               $this->queried_object = NULL;
-               $this->queried_object_id = 0;
+               $this->queried_object = null;
+               $this->queried_object_id = null;
 
                if ( $this->is_category || $this->is_tag || $this->is_tax ) {
-                       $tax_query_in_and = wp_list_filter( $this->tax_query->queries, array( 'operator' => 'NOT IN' ), 'NOT' );
+                       if ( $this->is_category ) {
+                               if ( $this->get( 'cat' ) ) {
+                                       $term = get_term( $this->get( 'cat' ), 'category' );
+                               } elseif ( $this->get( 'category_name' ) ) {
+                                       $term = get_term_by( 'slug', $this->get( 'category_name' ), 'category' );
+                               }
+                       } elseif ( $this->is_tag ) {
+                               if ( $this->get( 'tag_id' ) ) {
+                                       $term = get_term( $this->get( 'tag_id' ), 'post_tag' );
+                               } elseif ( $this->get( 'tag' ) ) {
+                                       $term = get_term_by( 'slug', $this->get( 'tag' ), 'post_tag' );
+                               }
+                       } else {
+                               // For other tax queries, grab the first term from the first clause.
+                               $tax_query_in_and = wp_list_filter( $this->tax_query->queried_terms, array( 'operator' => 'NOT IN' ), 'NOT' );
 
-                       $query = reset( $tax_query_in_and );
+                               if ( ! empty( $tax_query_in_and ) ) {
+                                       $queried_taxonomies = array_keys( $tax_query_in_and );
+                                       $matched_taxonomy = reset( $queried_taxonomies );
+                                       $query = $tax_query_in_and[ $matched_taxonomy ];
 
-                       if ( 'term_id' == $query['field'] )
-                               $term = get_term( reset( $query['terms'] ), $query['taxonomy'] );
-                       else
-                               $term = get_term_by( $query['field'], reset( $query['terms'] ), $query['taxonomy'] );
+                                       if ( $query['terms'] ) {
+                                               if ( 'term_id' == $query['field'] ) {
+                                                       $term = get_term( reset( $query['terms'] ), $matched_taxonomy );
+                                               } else {
+                                                       $term = get_term_by( $query['field'], reset( $query['terms'] ), $matched_taxonomy );
+                                               }
+                                       }
+                               }
+                       }
 
-                       if ( $term && ! is_wp_error($term) )  {
+                       if ( ! empty( $term ) && ! is_wp_error( $term ) )  {
                                $this->queried_object = $term;
                                $this->queried_object_id = (int) $term->term_id;
+
+                               if ( $this->is_category && 'category' === $this->queried_object->taxonomy )
+                                       _make_cat_compat( $this->queried_object );
                        }
                } elseif ( $this->is_post_type_archive ) {
-                       $this->queried_object = get_post_type_object( $this->get('post_type') );
+                       $post_type = $this->get( 'post_type' );
+                       if ( is_array( $post_type ) )
+                               $post_type = reset( $post_type );
+                       $this->queried_object = get_post_type_object( $post_type );
                } elseif ( $this->is_posts_page ) {
                        $page_for_posts = get_option('page_for_posts');
-                       $this->queried_object = & get_page( $page_for_posts );
+                       $this->queried_object = get_post( $page_for_posts );
                        $this->queried_object_id = (int) $this->queried_object->ID;
-               } elseif ( $this->is_singular && !is_null($this->post) ) {
+               } elseif ( $this->is_singular && ! empty( $this->post ) ) {
                        $this->queried_object = $this->post;
                        $this->queried_object_id = (int) $this->post->ID;
                } elseif ( $this->is_author ) {
@@ -2918,7 +4101,7 @@ class WP_Query {
         *
         * @return int
         */
-       function get_queried_object_id() {
+       public function get_queried_object_id() {
                $this->get_queried_object();
 
                if ( isset($this->queried_object_id) ) {
@@ -2929,24 +4112,70 @@ class WP_Query {
        }
 
        /**
-        * PHP4 type constructor.
+        * Constructor.
         *
         * Sets up the WordPress query, if parameter is not empty.
         *
         * @since 1.5.0
         * @access public
         *
-        * @param string $query URL query string.
-        * @return WP_Query
+        * @param string|array $query URL query string or array of vars.
         */
-       function WP_Query($query = '') {
+       public function __construct($query = '') {
                if ( ! empty($query) ) {
                        $this->query($query);
                }
        }
 
        /**
-        * Is the query for an archive page?
+        * Make private properties readable for backwards compatibility.
+        *
+        * @since 4.0.0
+        * @access public
+        *
+        * @param string $name Property to get.
+        * @return mixed Property.
+        */
+       public function __get( $name ) {
+               if ( in_array( $name, $this->compat_fields ) ) {
+                       return $this->$name;
+               }
+       }
+
+       /**
+        * Make private properties checkable for backwards compatibility.
+        *
+        * @since 4.0.0
+        * @access public
+        *
+        * @param string $name Property to check if set.
+        * @return bool Whether the property is set.
+        */
+       public function __isset( $name ) {
+               if ( in_array( $name, $this->compat_fields ) ) {
+                       return isset( $this->$name );
+               }
+       }
+
+       /**
+        * Make private/protected methods readable for backwards compatibility.
+        *
+        * @since 4.0.0
+        * @access public
+        *
+        * @param callable $name      Method to call.
+        * @param array    $arguments Arguments to pass when calling.
+        * @return mixed|false Return value of the callback, false otherwise.
+        */
+       public function __call( $name, $arguments ) {
+               if ( in_array( $name, $this->compat_methods ) ) {
+                       return call_user_func_array( array( $this, $name ), $arguments );
+               }
+               return false;
+       }
+
+       /**
+        * Is the query for an existing archive page?
         *
         * Month, Year, Category, Author, Post Type archive...
         *
@@ -2954,40 +4183,63 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_archive() {
+       public function is_archive() {
                return (bool) $this->is_archive;
        }
 
        /**
-        * Is the query for a post type archive page?
+        * Is the query for an existing post type archive page?
         *
         * @since 3.1.0
         *
         * @param mixed $post_types Optional. Post type or array of posts types to check against.
         * @return bool
         */
-       function is_post_type_archive( $post_types = '' ) {
-               if ( empty( $post_types ) || !$this->is_post_type_archive )
+       public function is_post_type_archive( $post_types = '' ) {
+               if ( empty( $post_types ) || ! $this->is_post_type_archive )
                        return (bool) $this->is_post_type_archive;
 
-               $post_type_object = $this->get_queried_object();
+               $post_type = $this->get( 'post_type' );
+               if ( is_array( $post_type ) )
+                       $post_type = reset( $post_type );
+               $post_type_object = get_post_type_object( $post_type );
 
                return in_array( $post_type_object->name, (array) $post_types );
        }
 
        /**
-        * Is the query for an attachment page?
+        * Is the query for an existing attachment page?
         *
         * @since 3.1.0
         *
+        * @param mixed $attachment Attachment ID, title, slug, or array of such.
         * @return bool
         */
-       function is_attachment() {
-               return (bool) $this->is_attachment;
+       public function is_attachment( $attachment = '' ) {
+               if ( ! $this->is_attachment ) {
+                       return false;
+               }
+
+               if ( empty( $attachment ) ) {
+                       return true;
+               }
+
+               $attachment = (array) $attachment;
+
+               $post_obj = $this->get_queried_object();
+
+               if ( in_array( (string) $post_obj->ID, $attachment ) ) {
+                       return true;
+               } elseif ( in_array( $post_obj->post_title, $attachment ) ) {
+                       return true;
+               } elseif ( in_array( $post_obj->post_name, $attachment ) ) {
+                       return true;
+               }
+               return false;
        }
 
        /**
-        * Is the query for an author archive page?
+        * Is the query for an existing author archive page?
         *
         * If the $author parameter is specified, this function will additionally
         * check if the query is for one of the authors specified.
@@ -2997,7 +4249,7 @@ class WP_Query {
         * @param mixed $author Optional. User ID, nickname, nicename, or array of User IDs, nicknames, and nicenames
         * @return bool
         */
-       function is_author( $author = '' ) {
+       public function is_author( $author = '' ) {
                if ( !$this->is_author )
                        return false;
 
@@ -3008,7 +4260,7 @@ class WP_Query {
 
                $author = (array) $author;
 
-               if ( in_array( $author_obj->ID, $author ) )
+               if ( in_array( (string) $author_obj->ID, $author ) )
                        return true;
                elseif ( in_array( $author_obj->nickname, $author ) )
                        return true;
@@ -3019,7 +4271,7 @@ class WP_Query {
        }
 
        /**
-        * Is the query for a category archive page?
+        * Is the query for an existing category archive page?
         *
         * If the $category parameter is specified, this function will additionally
         * check if the query is for one of the categories specified.
@@ -3029,7 +4281,7 @@ class WP_Query {
         * @param mixed $category Optional. Category ID, name, slug, or array of Category IDs, names, and slugs.
         * @return bool
         */
-       function is_category( $category = '' ) {
+       public function is_category( $category = '' ) {
                if ( !$this->is_category )
                        return false;
 
@@ -3040,7 +4292,7 @@ class WP_Query {
 
                $category = (array) $category;
 
-               if ( in_array( $cat_obj->term_id, $category ) )
+               if ( in_array( (string) $cat_obj->term_id, $category ) )
                        return true;
                elseif ( in_array( $cat_obj->name, $category ) )
                        return true;
@@ -3051,35 +4303,39 @@ class WP_Query {
        }
 
        /**
-        * Is the query for a tag archive page?
+        * Is the query for an existing tag archive page?
         *
         * If the $tag parameter is specified, this function will additionally
         * check if the query is for one of the tags specified.
         *
         * @since 3.1.0
         *
-        * @param mixed $slug Optional. Tag slug or array of slugs.
+        * @param mixed $tag Optional. Tag ID, name, slug, or array of Tag IDs, names, and slugs.
         * @return bool
         */
-       function is_tag( $slug = '' ) {
-               if ( !$this->is_tag )
+       public function is_tag( $tag = '' ) {
+               if ( ! $this->is_tag )
                        return false;
 
-               if ( empty( $slug ) )
+               if ( empty( $tag ) )
                        return true;
 
                $tag_obj = $this->get_queried_object();
 
-               $slug = (array) $slug;
+               $tag = (array) $tag;
 
-               if ( in_array( $tag_obj->slug, $slug ) )
+               if ( in_array( (string) $tag_obj->term_id, $tag ) )
+                       return true;
+               elseif ( in_array( $tag_obj->name, $tag ) )
+                       return true;
+               elseif ( in_array( $tag_obj->slug, $tag ) )
                        return true;
 
                return false;
        }
 
        /**
-        * Is the query for a taxonomy archive page?
+        * Is the query for an existing taxonomy archive page?
         *
         * If the $taxonomy parameter is specified, this function will additionally
         * check if the query is for that specific $taxonomy.
@@ -3090,11 +4346,13 @@ class WP_Query {
         *
         * @since 3.1.0
         *
+        * @global array $wp_taxonomies
+        *
         * @param mixed $taxonomy Optional. Taxonomy slug or slugs.
-        * @param mixed $term. Optional. Term ID, name, slug or array of Term IDs, names, and slugs.
+        * @param mixed $term     Optional. Term ID, name, slug or array of Term IDs, names, and slugs.
         * @return bool
         */
-       function is_tax( $taxonomy = '', $term = '' ) {
+       public function is_tax( $taxonomy = '', $term = '' ) {
                global $wp_taxonomies;
 
                if ( !$this->is_tax )
@@ -3107,8 +4365,13 @@ class WP_Query {
                $tax_array = array_intersect( array_keys( $wp_taxonomies ), (array) $taxonomy );
                $term_array = (array) $term;
 
-               if ( empty( $term ) ) // Only a Taxonomy provided
-                       return isset( $queried_object->taxonomy ) && count( $tax_array ) && in_array( $queried_object->taxonomy, $tax_array );
+               // Check that the taxonomy matches.
+               if ( ! ( isset( $queried_object->taxonomy ) && count( $tax_array ) && in_array( $queried_object->taxonomy, $tax_array ) ) )
+                       return false;
+
+               // Only a Taxonomy provided.
+               if ( empty( $term ) )
+                       return true;
 
                return isset( $queried_object->term_id ) &&
                        count( array_intersect(
@@ -3124,30 +4387,29 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_comments_popup() {
+       public function is_comments_popup() {
                return (bool) $this->is_comments_popup;
        }
 
        /**
-        * Is the query for a date archive?
+        * Is the query for an existing date archive?
         *
         * @since 3.1.0
         *
         * @return bool
         */
-       function is_date() {
+       public function is_date() {
                return (bool) $this->is_date;
        }
 
-
        /**
-        * Is the query for a day archive?
+        * Is the query for an existing day archive?
         *
         * @since 3.1.0
         *
         * @return bool
         */
-       function is_day() {
+       public function is_day() {
                return (bool) $this->is_day;
        }
 
@@ -3159,7 +4421,7 @@ class WP_Query {
         * @param string|array $feeds Optional feed types to check.
         * @return bool
         */
-       function is_feed( $feeds = '' ) {
+       public function is_feed( $feeds = '' ) {
                if ( empty( $feeds ) || ! $this->is_feed )
                        return (bool) $this->is_feed;
                $qv = $this->get( 'feed' );
@@ -3175,7 +4437,7 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_comment_feed() {
+       public function is_comment_feed() {
                return (bool) $this->is_comment_feed;
        }
 
@@ -3192,12 +4454,10 @@ class WP_Query {
         * Otherwise the same as @see WP_Query::is_home()
         *
         * @since 3.1.0
-        * @uses is_home()
-        * @uses get_option()
         *
         * @return bool True, if front of site.
         */
-       function is_front_page() {
+       public function is_front_page() {
                // most likely case
                if ( 'posts' == get_option( 'show_on_front') && $this->is_home() )
                        return true;
@@ -3223,23 +4483,23 @@ class WP_Query {
         *
         * @return bool True if blog view homepage.
         */
-       function is_home() {
+       public function is_home() {
                return (bool) $this->is_home;
        }
 
        /**
-        * Is the query for a month archive?
+        * Is the query for an existing month archive?
         *
         * @since 3.1.0
         *
         * @return bool
         */
-       function is_month() {
+       public function is_month() {
                return (bool) $this->is_month;
        }
 
        /**
-        * Is the query for a single page?
+        * Is the query for an existing single page?
         *
         * If the $page parameter is specified, this function will additionally
         * check if the query is for one of the pages specified.
@@ -3249,10 +4509,10 @@ class WP_Query {
         *
         * @since 3.1.0
         *
-        * @param mixed $page Page ID, title, slug, or array of such.
-        * @return bool
+        * @param int|string|array $page Optional. Page ID, title, slug, path, or array of such. Default empty.
+        * @return bool Whether the query is for an existing single page.
         */
-       function is_page( $page = '' ) {
+       public function is_page( $page = '' ) {
                if ( !$this->is_page )
                        return false;
 
@@ -3263,12 +4523,24 @@ class WP_Query {
 
                $page = (array) $page;
 
-               if ( in_array( $page_obj->ID, $page ) )
+               if ( in_array( (string) $page_obj->ID, $page ) ) {
                        return true;
-               elseif ( in_array( $page_obj->post_title, $page ) )
+               } elseif ( in_array( $page_obj->post_title, $page ) ) {
                        return true;
-               else if ( in_array( $page_obj->post_name, $page ) )
+               } elseif ( in_array( $page_obj->post_name, $page ) ) {
                        return true;
+               } else {
+                       foreach ( $page as $pagepath ) {
+                               if ( ! strpos( $pagepath, '/' ) ) {
+                                       continue;
+                               }
+                               $pagepath_obj = get_page_by_path( $pagepath );
+
+                               if ( $pagepath_obj && ( $pagepath_obj->ID == $page_obj->ID ) ) {
+                                       return true;
+                               }
+                       }
+               }
 
                return false;
        }
@@ -3280,7 +4552,7 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_paged() {
+       public function is_paged() {
                return (bool) $this->is_paged;
        }
 
@@ -3291,7 +4563,7 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_preview() {
+       public function is_preview() {
                return (bool) $this->is_preview;
        }
 
@@ -3302,7 +4574,7 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_robots() {
+       public function is_robots() {
                return (bool) $this->is_robots;
        }
 
@@ -3313,12 +4585,12 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_search() {
+       public function is_search() {
                return (bool) $this->is_search;
        }
 
        /**
-        * Is the query for a single post?
+        * Is the query for an existing single post?
         *
         * Works for any post type, except attachments and pages
         *
@@ -3330,10 +4602,10 @@ class WP_Query {
         *
         * @since 3.1.0
         *
-        * @param mixed $post Post ID, title, slug, or array of such.
-        * @return bool
+        * @param int|string|array $post Optional. Post ID, title, slug, path, or array of such. Default empty.
+        * @return bool Whether the query is for an existing single post.
         */
-       function is_single( $post = '' ) {
+       public function is_single( $post = '' ) {
                if ( !$this->is_single )
                        return false;
 
@@ -3344,18 +4616,29 @@ class WP_Query {
 
                $post = (array) $post;
 
-               if ( in_array( $post_obj->ID, $post ) )
+               if ( in_array( (string) $post_obj->ID, $post ) ) {
                        return true;
-               elseif ( in_array( $post_obj->post_title, $post ) )
+               } elseif ( in_array( $post_obj->post_title, $post ) ) {
                        return true;
-               elseif ( in_array( $post_obj->post_name, $post ) )
+               } elseif ( in_array( $post_obj->post_name, $post ) ) {
                        return true;
+               } else {
+                       foreach ( $post as $postpath ) {
+                               if ( ! strpos( $postpath, '/' ) ) {
+                                       continue;
+                               }
+                               $postpath_obj = get_page_by_path( $postpath, OBJECT, $post_obj->post_type );
 
+                               if ( $postpath_obj && ( $postpath_obj->ID == $post_obj->ID ) ) {
+                                       return true;
+                               }
+                       }
+               }
                return false;
        }
 
        /**
-        * Is the query for a single post of any post type (post, attachment, page, ... )?
+        * Is the query for an existing single post of any post type (post, attachment, page, ... )?
         *
         * If the $post_types parameter is specified, this function will additionally
         * check if the query is for one of the Posts Types specified.
@@ -3365,10 +4648,10 @@ class WP_Query {
         *
         * @since 3.1.0
         *
-        * @param mixed $post_types Optional. Post Type or array of Post Types
-        * @return bool
+        * @param string|array $post_types Optional. Post type or array of post types. Default empty.
+        * @return bool Whether the query is for an existing single post of any of the given post types.
         */
-       function is_singular( $post_types = '' ) {
+       public function is_singular( $post_types = '' ) {
                if ( empty( $post_types ) || !$this->is_singular )
                        return (bool) $this->is_singular;
 
@@ -3384,7 +4667,7 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_time() {
+       public function is_time() {
                return (bool) $this->is_time;
        }
 
@@ -3395,18 +4678,18 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_trackback() {
+       public function is_trackback() {
                return (bool) $this->is_trackback;
        }
 
        /**
-        * Is the query for a specific year?
+        * Is the query for an existing year archive?
         *
         * @since 3.1.0
         *
         * @return bool
         */
-       function is_year() {
+       public function is_year() {
                return (bool) $this->is_year;
        }
 
@@ -3417,9 +4700,276 @@ class WP_Query {
         *
         * @return bool
         */
-       function is_404() {
+       public function is_404() {
                return (bool) $this->is_404;
        }
+
+       /**
+        * Is the query for an embedded post?
+        *
+        * @since 4.4.0
+        *
+        * @return bool
+        */
+       public function is_embed() {
+               return (bool) $this->is_embed;
+       }
+
+       /**
+        * Is the query the main query?
+        *
+        * @since 3.3.0
+        *
+        * @global WP_Query $wp_query Global WP_Query instance.
+        *
+        * @return bool
+        */
+       public function is_main_query() {
+               global $wp_the_query;
+               return $wp_the_query === $this;
+       }
+
+       /**
+        * Set up global post data.
+        *
+        * @since 4.1.0
+        * @since 4.4.0 Added the ability to pass a post ID to `$post`.
+        *
+        * @global int             $id
+        * @global WP_User         $authordata
+        * @global string|int|bool $currentday
+        * @global string|int|bool $currentmonth
+        * @global int             $page
+        * @global array           $pages
+        * @global int             $multipage
+        * @global int             $more
+        * @global int             $numpages
+        *
+        * @param WP_Post|object|int $post WP_Post instance or Post ID/object.
+        * @return true True when finished.
+        */
+       public function setup_postdata( $post ) {
+               global $id, $authordata, $currentday, $currentmonth, $page, $pages, $multipage, $more, $numpages;
+
+               if ( ! ( $post instanceof WP_Post ) ) {
+                       $post = get_post( $post );
+               }
+
+               if ( ! $post ) {
+                       return;
+               }
+
+               $id = (int) $post->ID;
+
+               $authordata = get_userdata($post->post_author);
+
+               $currentday = mysql2date('d.m.y', $post->post_date, false);
+               $currentmonth = mysql2date('m', $post->post_date, false);
+               $numpages = 1;
+               $multipage = 0;
+               $page = $this->get( 'page' );
+               if ( ! $page )
+                       $page = 1;
+
+               /*
+                * Force full post content when viewing the permalink for the $post,
+                * or when on an RSS feed. Otherwise respect the 'more' tag.
+                */
+               if ( $post->ID === get_queried_object_id() && ( $this->is_page() || $this->is_single() ) ) {
+                       $more = 1;
+               } elseif ( $this->is_feed() ) {
+                       $more = 1;
+               } else {
+                       $more = 0;
+               }
+
+               $content = $post->post_content;
+               if ( false !== strpos( $content, '<!--nextpage-->' ) ) {
+                       $content = str_replace( "\n<!--nextpage-->\n", '<!--nextpage-->', $content );
+                       $content = str_replace( "\n<!--nextpage-->", '<!--nextpage-->', $content );
+                       $content = str_replace( "<!--nextpage-->\n", '<!--nextpage-->', $content );
+
+                       // Ignore nextpage at the beginning of the content.
+                       if ( 0 === strpos( $content, '<!--nextpage-->' ) )
+                               $content = substr( $content, 15 );
+
+                       $pages = explode('<!--nextpage-->', $content);
+               } else {
+                       $pages = array( $post->post_content );
+               }
+
+               /**
+                * Filter the "pages" derived from splitting the post content.
+                *
+                * "Pages" are determined by splitting the post content based on the presence
+                * of `<!-- nextpage -->` tags.
+                *
+                * @since 4.4.0
+                *
+                * @param array   $pages Array of "pages" derived from the post content.
+                *                       of `<!-- nextpage -->` tags..
+                * @param WP_Post $post  Current post object.
+                */
+               $pages = apply_filters( 'content_pagination', $pages, $post );
+
+               $numpages = count( $pages );
+
+               if ( $numpages > 1 ) {
+                       if ( $page > 1 ) {
+                               $more = 1;
+                       }
+                       $multipage = 1;
+               } else {
+                       $multipage = 0;
+               }
+
+               /**
+                * Fires once the post data has been setup.
+                *
+                * @since 2.8.0
+                * @since 4.1.0 Introduced `$this` parameter.
+                *
+                * @param WP_Post  &$post The Post object (passed by reference).
+                * @param WP_Query &$this The current Query object (passed by reference).
+                */
+               do_action_ref_array( 'the_post', array( &$post, &$this ) );
+
+               return true;
+       }
+       /**
+        * After looping through a nested query, this function
+        * restores the $post global to the current post in this query.
+        *
+        * @since 3.7.0
+        *
+        * @global WP_Post $post
+        */
+       public function reset_postdata() {
+               if ( ! empty( $this->post ) ) {
+                       $GLOBALS['post'] = $this->post;
+                       $this->setup_postdata( $this->post );
+               }
+       }
+
+       /**
+        * Lazy-loads termmeta for located posts.
+        *
+        * As a rule, term queries (`get_terms()` and `wp_get_object_terms()`) prime the metadata cache for matched
+        * terms by default. However, this can cause a slight performance penalty, especially when that metadata is
+        * not actually used. In the context of a `WP_Query` instance, we're able to avoid this potential penalty.
+        * `update_object_term_cache()`, called from `update_post_caches()`, does not 'update_term_meta_cache'.
+        * Instead, the first time `get_term_meta()` is called from within a `WP_Query` loop, the current method
+        * detects the fact, and then primes the metadata cache for all terms attached to all posts in the loop,
+        * with a single database query.
+        *
+        * This method is public so that it can be used as a filter callback. As a rule, there is no need to invoke it
+        * directly, from either inside or outside the `WP_Query` object.
+        *
+        * @since 4.4.0
+        * @access public
+        *
+        * @param mixed $check  The `$check` param passed from the 'get_term_metadata' hook.
+        * @param int  $term_id ID of the term whose metadata is being cached.
+        * @return mixed In order not to short-circuit `get_metadata()`. Generally, this is `null`, but it could be
+        *               another value if filtered by a plugin.
+        */
+       public function lazyload_term_meta( $check, $term_id ) {
+               /*
+                * We only do this once per `WP_Query` instance.
+                * Can't use `remove_filter()` because of non-unique object hashes.
+                */
+               if ( $this->updated_term_meta_cache ) {
+                       return $check;
+               }
+
+               // We can only lazyload if the entire post object is present.
+               $posts = array();
+               foreach ( $this->posts as $post ) {
+                       if ( $post instanceof WP_Post ) {
+                               $posts[] = $post;
+                       }
+               }
+
+               if ( ! empty( $posts ) ) {
+                       // Fetch cached term_ids for each post. Keyed by term_id for faster lookup.
+                       $term_ids = array();
+                       foreach ( $posts as $post ) {
+                               $taxonomies = get_object_taxonomies( $post->post_type );
+                               foreach ( $taxonomies as $taxonomy ) {
+                                       // Term cache should already be primed by 'update_post_term_cache'.
+                                       $terms = get_object_term_cache( $post->ID, $taxonomy );
+                                       if ( false !== $terms ) {
+                                               foreach ( $terms as $term ) {
+                                                       if ( ! isset( $term_ids[ $term->term_id ] ) ) {
+                                                               $term_ids[ $term->term_id ] = 1;
+                                                       }
+                                               }
+                                       }
+                               }
+                       }
+
+                       /*
+                        * Only update the metadata cache for terms belonging to these posts if the term_id passed
+                        * to `get_term_meta()` matches one of those terms. This prevents a single call to
+                        * `get_term_meta()` from priming metadata for all `WP_Query` objects.
+                        */
+                       if ( isset( $term_ids[ $term_id ] ) ) {
+                               update_termmeta_cache( array_keys( $term_ids ) );
+                               $this->updated_term_meta_cache = true;
+                       }
+               }
+
+               // If no terms were found, there's no need to run this again.
+               if ( empty( $term_ids ) ) {
+                       $this->updated_term_meta_cache = true;
+               }
+
+               return $check;
+       }
+
+       /**
+        * Lazy-load comment meta when inside of a `WP_Query` loop.
+        *
+        * This method is public so that it can be used as a filter callback. As a rule, there is no need to invoke it
+        * directly, from either inside or outside the `WP_Query` object.
+        *
+        * @since 4.4.0
+        *
+        * @param mixed $check     The `$check` param passed from the 'get_comment_metadata' hook.
+        * @param int  $comment_id ID of the comment whose metadata is being cached.
+        * @return mixed The original value of `$check`, to not affect 'get_comment_metadata'.
+        */
+       public function lazyload_comment_meta( $check, $comment_id ) {
+               /*
+                * We only do this once per `WP_Query` instance.
+                * Can't use `remove_filter()` because of non-unique object hashes.
+                */
+               if ( $this->updated_comment_meta_cache ) {
+                       return $check;
+               }
+
+               // Don't use `wp_list_pluck()` to avoid by-reference manipulation.
+               $comment_ids = array();
+               if ( is_array( $this->comments ) ) {
+                       foreach ( $this->comments as $comment ) {
+                               $comment_ids[] = $comment->comment_ID;
+                       }
+               }
+
+               /*
+                * Only update the metadata cache for comments belonging to these posts if the comment_id passed
+                * to `get_comment_meta()` matches one of those comments. This prevents a single call to
+                * `get_comment_meta()` from priming metadata for all `WP_Query` objects.
+                */
+               if ( in_array( $comment_id, $comment_ids ) ) {
+                       update_meta_cache( 'comment', $comment_ids );
+                       $this->updated_comment_meta_cache = true;
+               } elseif ( empty( $comment_ids ) ) {
+                       $this->updated_comment_meta_cache = true;
+               }
+
+               return $check;
+       }
 }
 
 /**
@@ -3428,23 +4978,37 @@ class WP_Query {
  * Attempts to find the current slug from the past slugs.
  *
  * @since 2.1.0
- * @uses $wp_query
- * @uses $wpdb
  *
- * @return null If no link is found, null is returned.
+ * @global WP_Query   $wp_query   Global WP_Query instance.
+ * @global wpdb       $wpdb       WordPress database abstraction object.
+ * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
  */
 function wp_old_slug_redirect() {
-       global $wp_query;
-       if ( is_404() && '' != $wp_query->query_vars['name'] ) :
+       global $wp_query, $wp_rewrite;
+
+       if ( get_queried_object() ) {
+               return;
+       }
+
+       if ( '' !== $wp_query->query_vars['name'] ) :
                global $wpdb;
 
                // Guess the current post_type based on the query vars.
-               if ( get_query_var('post_type') )
-                       $post_type = get_query_var('post_type');
-               elseif ( !empty($wp_query->query_vars['pagename']) )
+               if ( get_query_var( 'post_type' ) ) {
+                       $post_type = get_query_var( 'post_type' );
+               } elseif ( get_query_var( 'attachment' ) ) {
+                       $post_type = 'attachment';
+               } elseif ( ! empty( $wp_query->query_vars['pagename'] ) ) {
                        $post_type = 'page';
-               else
+               } else {
                        $post_type = 'post';
+               }
+
+               if ( is_array( $post_type ) ) {
+                       if ( count( $post_type ) > 1 )
+                               return;
+                       $post_type = reset( $post_type );
+               }
 
                // Do not attempt redirect for hierarchical post types
                if ( is_post_type_hierarchical( $post_type ) )
@@ -3466,12 +5030,37 @@ function wp_old_slug_redirect() {
                if ( ! $id )
                        return;
 
-               $link = get_permalink($id);
+               $link = get_permalink( $id );
+
+               if ( is_feed() ) {
+                       $link = user_trailingslashit( trailingslashit( $link ) . 'feed' );
+               } elseif ( isset( $GLOBALS['wp_query']->query_vars['paged'] ) && $GLOBALS['wp_query']->query_vars['paged'] > 1 ) {
+                       $link = user_trailingslashit( trailingslashit( $link ) . 'page/' . $GLOBALS['wp_query']->query_vars['paged'] );
+               } elseif( is_embed() ) {
+                       $link = user_trailingslashit( trailingslashit( $link ) . 'embed' );
+               } elseif ( is_404() ) {
+                       // Add rewrite endpoints if necessary.
+                       foreach ( $wp_rewrite->endpoints as $endpoint ) {
+                               if ( $endpoint[2] && false !== get_query_var( $endpoint[2], false ) ) {
+                                       $link = user_trailingslashit( trailingslashit( $link ) . $endpoint[1] );
+                               }
+                       }
+               }
 
-               if ( !$link )
+               /**
+                * Filter the old slug redirect URL.
+                *
+                * @since 4.4.0
+                *
+                * @param string $link The redirect URL.
+                */
+               $link = apply_filters( 'old_slug_redirect_url', $link );
+
+               if ( ! $link ) {
                        return;
+               }
 
-               wp_redirect($link, '301'); // Permanent redirect
+               wp_redirect( $link, 301 ); // Permanent redirect
                exit;
        endif;
 }
@@ -3480,43 +5069,19 @@ function wp_old_slug_redirect() {
  * Set up global post data.
  *
  * @since 1.5.0
+ * @since 4.4.0 Added the ability to pass a post ID to `$post`.
+ *
+ * @global WP_Query $wp_query Global WP_Query instance.
  *
- * @param object $post Post data.
- * @uses do_action_ref_array() Calls 'the_post'
+ * @param WP_Post|object|int $post WP_Post instance or Post ID/object.
  * @return bool True when finished.
  */
-function setup_postdata($post) {
-       global $id, $authordata, $currentday, $currentmonth, $page, $pages, $multipage, $more, $numpages;
-
-       $id = (int) $post->ID;
-
-       $authordata = get_userdata($post->post_author);
+function setup_postdata( $post ) {
+       global $wp_query;
 
-       $currentday = mysql2date('d.m.y', $post->post_date, false);
-       $currentmonth = mysql2date('m', $post->post_date, false);
-       $numpages = 1;
-       $page = get_query_var('page');
-       if ( !$page )
-               $page = 1;
-       if ( is_single() || is_page() || is_feed() )
-               $more = 1;
-       $content = $post->post_content;
-       if ( strpos( $content, '<!--nextpage-->' ) ) {
-               if ( $page > 1 )
-                       $more = 1;
-               $multipage = 1;
-               $content = str_replace("\n<!--nextpage-->\n", '<!--nextpage-->', $content);
-               $content = str_replace("\n<!--nextpage-->", '<!--nextpage-->', $content);
-               $content = str_replace("<!--nextpage-->\n", '<!--nextpage-->', $content);
-               $pages = explode('<!--nextpage-->', $content);
-               $numpages = count($pages);
-       } else {
-               $pages = array( $post->post_content );
-               $multipage = 0;
+       if ( ! empty( $wp_query ) && $wp_query instanceof WP_Query ) {
+               return $wp_query->setup_postdata( $post );
        }
 
-       do_action_ref_array('the_post', array(&$post));
-
-       return true;
+       return false;
 }
-?>