WordPress 4.3

[autoinstalls/wordpress.git] / wp-includes / post.php

<?php
/**
 * Post functions and post utility function.
 *
 * @package WordPress
 * @subpackage Post
 * @since 1.5.0
 */

//
// Post Type Registration
//

/**
 * Creates the initial post types when 'init' action is fired.
 *
 * @since 2.9.0
 */
function create_initial_post_types() {
        register_post_type( 'post', array(
                'labels' => array(
                        'name_admin_bar' => _x( 'Post', 'add new on admin bar' ),
                ),
                'public'  => true,
                '_builtin' => true, /* internal use only. don't use this when registering your own post type. */
                '_edit_link' => 'post.php?post=%d', /* internal use only. don't use this when registering your own post type. */
                'capability_type' => 'post',
                'map_meta_cap' => true,
                'hierarchical' => false,
                'rewrite' => false,
                'query_var' => false,
                'delete_with_user' => true,
                'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'excerpt', 'trackbacks', 'custom-fields', 'comments', 'revisions', 'post-formats' ),
        ) );

        register_post_type( 'page', array(
                'labels' => array(
                        'name_admin_bar' => _x( 'Page', 'add new on admin bar' ),
                ),
                'public' => true,
                'publicly_queryable' => false,
                '_builtin' => true, /* internal use only. don't use this when registering your own post type. */
                '_edit_link' => 'post.php?post=%d', /* internal use only. don't use this when registering your own post type. */
                'capability_type' => 'page',
                'map_meta_cap' => true,
                'hierarchical' => true,
                'rewrite' => false,
                'query_var' => false,
                'delete_with_user' => true,
                'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'page-attributes', 'custom-fields', 'comments', 'revisions' ),
        ) );

        register_post_type( 'attachment', array(
                'labels' => array(
                        'name' => _x('Media', 'post type general name'),
                        'name_admin_bar' => _x( 'Media', 'add new from admin bar' ),
                        'add_new' => _x( 'Add New', 'add new media' ),
                        'edit_item' => __( 'Edit Media' ),
                        'view_item' => __( 'View Attachment Page' ),
                ),
                'public' => true,
                'show_ui' => true,
                '_builtin' => true, /* internal use only. don't use this when registering your own post type. */
                '_edit_link' => 'post.php?post=%d', /* internal use only. don't use this when registering your own post type. */
                'capability_type' => 'post',
                'capabilities' => array(
                        'create_posts' => 'upload_files',
                ),
                'map_meta_cap' => true,
                'hierarchical' => false,
                'rewrite' => false,
                'query_var' => false,
                'show_in_nav_menus' => false,
                'delete_with_user' => true,
                'supports' => array( 'title', 'author', 'comments' ),
        ) );
        add_post_type_support( 'attachment:audio', 'thumbnail' );
        add_post_type_support( 'attachment:video', 'thumbnail' );

        register_post_type( 'revision', array(
                'labels' => array(
                        'name' => __( 'Revisions' ),
                        'singular_name' => __( 'Revision' ),
                ),
                'public' => false,
                '_builtin' => true, /* internal use only. don't use this when registering your own post type. */
                '_edit_link' => 'revision.php?revision=%d', /* internal use only. don't use this when registering your own post type. */
                'capability_type' => 'post',
                'map_meta_cap' => true,
                'hierarchical' => false,
                'rewrite' => false,
                'query_var' => false,
                'can_export' => false,
                'delete_with_user' => true,
                'supports' => array( 'author' ),
        ) );

        register_post_type( 'nav_menu_item', array(
                'labels' => array(
                        'name' => __( 'Navigation Menu Items' ),
                        'singular_name' => __( 'Navigation Menu Item' ),
                ),
                'public' => false,
                '_builtin' => true, /* internal use only. don't use this when registering your own post type. */
                'hierarchical' => false,
                'rewrite' => false,
                'delete_with_user' => false,
                'query_var' => false,
        ) );

        register_post_status( 'publish', array(
                'label'       => _x( 'Published', 'post' ),
                'public'      => true,
                '_builtin'    => true, /* internal use only. */
                'label_count' => _n_noop( 'Published <span class="count">(%s)</span>', 'Published <span class="count">(%s)</span>' ),
        ) );

        register_post_status( 'future', array(
                'label'       => _x( 'Scheduled', 'post' ),
                'protected'   => true,
                '_builtin'    => true, /* internal use only. */
                'label_count' => _n_noop('Scheduled <span class="count">(%s)</span>', 'Scheduled <span class="count">(%s)</span>' ),
        ) );

        register_post_status( 'draft', array(
                'label'       => _x( 'Draft', 'post' ),
                'protected'   => true,
                '_builtin'    => true, /* internal use only. */
                'label_count' => _n_noop( 'Draft <span class="count">(%s)</span>', 'Drafts <span class="count">(%s)</span>' ),
        ) );

        register_post_status( 'pending', array(
                'label'       => _x( 'Pending', 'post' ),
                'protected'   => true,
                '_builtin'    => true, /* internal use only. */
                'label_count' => _n_noop( 'Pending <span class="count">(%s)</span>', 'Pending <span class="count">(%s)</span>' ),
        ) );

        register_post_status( 'private', array(
                'label'       => _x( 'Private', 'post' ),
                'private'     => true,
                '_builtin'    => true, /* internal use only. */
                'label_count' => _n_noop( 'Private <span class="count">(%s)</span>', 'Private <span class="count">(%s)</span>' ),
        ) );

        register_post_status( 'trash', array(
                'label'       => _x( 'Trash', 'post' ),
                'internal'    => true,
                '_builtin'    => true, /* internal use only. */
                'label_count' => _n_noop( 'Trash <span class="count">(%s)</span>', 'Trash <span class="count">(%s)</span>' ),
                'show_in_admin_status_list' => true,
        ) );

        register_post_status( 'auto-draft', array(
                'label'    => 'auto-draft',
                'internal' => true,
                '_builtin' => true, /* internal use only. */
        ) );

        register_post_status( 'inherit', array(
                'label'    => 'inherit',
                'internal' => true,
                '_builtin' => true, /* internal use only. */
                'exclude_from_search' => false,
        ) );
}

/**
 * Retrieve attached file path based on attachment ID.
 *
 * By default the path will go through the 'get_attached_file' filter, but
 * passing a true to the $unfiltered argument of get_attached_file() will
 * return the file path unfiltered.
 *
 * The function works by getting the single post meta name, named
 * '_wp_attached_file' and returning it. This is a convenience function to
 * prevent looking up the meta name and provide a mechanism for sending the
 * attached filename through a filter.
 *
 * @since 2.0.0
 *
 * @param int  $attachment_id Attachment ID.
 * @param bool $unfiltered    Optional. Whether to apply filters. Default false.
 * @return string|false The file path to where the attached file should be, false otherwise.
 */
function get_attached_file( $attachment_id, $unfiltered = false ) {
        $file = get_post_meta( $attachment_id, '_wp_attached_file', true );
        // If the file is relative, prepend upload dir.
        if ( $file && 0 !== strpos($file, '/') && !preg_match('|^.:\\\|', $file) && ( ($uploads = wp_upload_dir()) && false === $uploads['error'] ) )
                $file = $uploads['basedir'] . "/$file";
        if ( $unfiltered )
                return $file;

        /**
         * Filter the attached file based on the given ID.
         *
         * @since 2.1.0
         *
         * @param string $file          Path to attached file.
         * @param int    $attachment_id Attachment ID.
         */
        return apply_filters( 'get_attached_file', $file, $attachment_id );
}

/**
 * Update attachment file path based on attachment ID.
 *
 * Used to update the file path of the attachment, which uses post meta name
 * '_wp_attached_file' to store the path of the attachment.
 *
 * @since 2.1.0
 *
 * @param int    $attachment_id Attachment ID.
 * @param string $file          File path for the attachment.
 * @return bool True on success, false on failure.
 */
function update_attached_file( $attachment_id, $file ) {
        if ( !get_post( $attachment_id ) )
                return false;

        /**
         * Filter the path to the attached file to update.
         *
         * @since 2.1.0
         *
         * @param string $file          Path to the attached file to update.
         * @param int    $attachment_id Attachment ID.
         */
        $file = apply_filters( 'update_attached_file', $file, $attachment_id );

        if ( $file = _wp_relative_upload_path( $file ) )
                return update_post_meta( $attachment_id, '_wp_attached_file', $file );
        else
                return delete_post_meta( $attachment_id, '_wp_attached_file' );
}

/**
 * Return relative path to an uploaded file.
 *
 * The path is relative to the current upload dir.
 *
 * @since 2.9.0
 *
 * @param string $path Full path to the file.
 * @return string Relative path on success, unchanged path on failure.
 */
function _wp_relative_upload_path( $path ) {
        $new_path = $path;

        $uploads = wp_upload_dir();
        if ( 0 === strpos( $new_path, $uploads['basedir'] ) ) {
                        $new_path = str_replace( $uploads['basedir'], '', $new_path );
                        $new_path = ltrim( $new_path, '/' );
        }

        /**
         * Filter the relative path to an uploaded file.
         *
         * @since 2.9.0
         *
         * @param string $new_path Relative path to the file.
         * @param string $path     Full path to the file.
         */
        return apply_filters( '_wp_relative_upload_path', $new_path, $path );
}

/**
 * Retrieve all children of the post parent ID.
 *
 * Normally, without any enhancements, the children would apply to pages. In the
 * context of the inner workings of WordPress, pages, posts, and attachments
 * share the same table, so therefore the functionality could apply to any one
 * of them. It is then noted that while this function does not work on posts, it
 * does not mean that it won't work on posts. It is recommended that you know
 * what context you wish to retrieve the children of.
 *
 * Attachments may also be made the child of a post, so if that is an accurate
 * statement (which needs to be verified), it would then be possible to get
 * all of the attachments for a post. Attachments have since changed since
 * version 2.5, so this is most likely unaccurate, but serves generally as an
 * example of what is possible.
 *
 * The arguments listed as defaults are for this function and also of the
 * {@link get_posts()} function. The arguments are combined with the
 * get_children defaults and are then passed to the {@link get_posts()}
 * function, which accepts additional arguments. You can replace the defaults in
 * this function, listed below and the additional arguments listed in the
 * {@link get_posts()} function.
 *
 * The 'post_parent' is the most important argument and important attention
 * needs to be paid to the $args parameter. If you pass either an object or an
 * integer (number), then just the 'post_parent' is grabbed and everything else
 * is lost. If you don't specify any arguments, then it is assumed that you are
 * in The Loop and the post parent will be grabbed for from the current post.
 *
 * The 'post_parent' argument is the ID to get the children. The 'numberposts'
 * is the amount of posts to retrieve that has a default of '-1', which is
 * used to get all of the posts. Giving a number higher than 0 will only
 * retrieve that amount of posts.
 *
 * The 'post_type' and 'post_status' arguments can be used to choose what
 * criteria of posts to retrieve. The 'post_type' can be anything, but WordPress
 * post types are 'post', 'pages', and 'attachments'. The 'post_status'
 * argument will accept any post status within the write administration panels.
 *
 * @since 2.0.0
 *
 * @see get_posts()
 * @todo Check validity of description.
 *
 * @global WP_Post $post
 *
 * @param mixed  $args   Optional. User defined arguments for replacing the defaults. Default empty.
 * @param string $output Optional. Constant for return type. Accepts OBJECT, ARRAY_A, ARRAY_N.
 *                       Default OBJECt.
 * @return array Array of children, where the type of each element is determined by $output parameter.
 *               Empty array on failure.
 */
function get_children( $args = '', $output = OBJECT ) {
        $kids = array();
        if ( empty( $args ) ) {
                if ( isset( $GLOBALS['post'] ) ) {
                        $args = array('post_parent' => (int) $GLOBALS['post']->post_parent );
                } else {
                        return $kids;
                }
        } elseif ( is_object( $args ) ) {
                $args = array('post_parent' => (int) $args->post_parent );
        } elseif ( is_numeric( $args ) ) {
                $args = array('post_parent' => (int) $args);
        }

        $defaults = array(
                'numberposts' => -1, 'post_type' => 'any',
                'post_status' => 'any', 'post_parent' => 0,
        );

        $r = wp_parse_args( $args, $defaults );

        $children = get_posts( $r );

        if ( ! $children )
                return $kids;

        if ( ! empty( $r['fields'] ) )
                return $children;

        update_post_cache($children);

        foreach ( $children as $key => $child )
                $kids[$child->ID] = $children[$key];

        if ( $output == OBJECT ) {
                return $kids;
        } elseif ( $output == ARRAY_A ) {
                $weeuns = array();
                foreach ( (array) $kids as $kid ) {
                        $weeuns[$kid->ID] = get_object_vars($kids[$kid->ID]);
                }
                return $weeuns;
        } elseif ( $output == ARRAY_N ) {
                $babes = array();
                foreach ( (array) $kids as $kid ) {
                        $babes[$kid->ID] = array_values(get_object_vars($kids[$kid->ID]));
                }
                return $babes;
        } else {
                return $kids;
        }
}

/**
 * Get extended entry info (<!--more-->).
 *
 * There should not be any space after the second dash and before the word
 * 'more'. There can be text or space(s) after the word 'more', but won't be
 * referenced.
 *
 * The returned array has 'main', 'extended', and 'more_text' keys. Main has the text before
 * the `<!--more-->`. The 'extended' key has the content after the
 * `<!--more-->` comment. The 'more_text' key has the custom "Read More" text.
 *
 * @since 1.0.0
 *
 * @param string $post Post content.
 * @return array Post before ('main'), after ('extended'), and custom readmore ('more_text').
 */
function get_extended( $post ) {
        //Match the new style more links.
        if ( preg_match('/<!--more(.*?)?-->/', $post, $matches) ) {
                list($main, $extended) = explode($matches[0], $post, 2);
                $more_text = $matches[1];
        } else {
                $main = $post;
                $extended = '';
                $more_text = '';
        }

        //  leading and trailing whitespace.
        $main = preg_replace('/^[\s]*(.*)[\s]*$/', '\\1', $main);
        $extended = preg_replace('/^[\s]*(.*)[\s]*$/', '\\1', $extended);
        $more_text = preg_replace('/^[\s]*(.*)[\s]*$/', '\\1', $more_text);

        return array( 'main' => $main, 'extended' => $extended, 'more_text' => $more_text );
}

/**
 * Retrieves post data given a post ID or post object.
 *
 * See {@link sanitize_post()} for optional $filter values. Also, the parameter
 * $post, must be given as a variable, since it is passed by reference.
 *
 * @since 1.5.1
 *
 * @global WP_Post $post
 *
 * @param int|WP_Post|null $post   Optional. Post ID or post object. Defaults to global $post.
 * @param string           $output Optional, default is Object. Accepts OBJECT, ARRAY_A, or ARRAY_N.
 *                                 Default OBJECT.
 * @param string           $filter Optional. Type of filter to apply. Accepts 'raw', 'edit', 'db',
 *                                 or 'display'. Default 'raw'.
 * @return WP_Post|array|null Type corresponding to $output on success or null on failure.
 *                            When $output is OBJECT, a `WP_Post` instance is returned.
 */
function get_post( $post = null, $output = OBJECT, $filter = 'raw' ) {
        if ( empty( $post ) && isset( $GLOBALS['post'] ) )
                $post = $GLOBALS['post'];

        if ( $post instanceof WP_Post ) {
                $_post = $post;
        } elseif ( is_object( $post ) ) {
                if ( empty( $post->filter ) ) {
                        $_post = sanitize_post( $post, 'raw' );
                        $_post = new WP_Post( $_post );
                } elseif ( 'raw' == $post->filter ) {
                        $_post = new WP_Post( $post );
                } else {
                        $_post = WP_Post::get_instance( $post->ID );
                }
        } else {
                $_post = WP_Post::get_instance( $post );
        }

        if ( ! $_post )
                return null;

        $_post = $_post->filter( $filter );

        if ( $output == ARRAY_A )
                return $_post->to_array();
        elseif ( $output == ARRAY_N )
                return array_values( $_post->to_array() );

        return $_post;
}

/**
 * WordPress Post class.
 *
 * @since 3.5.0
 *
 * @property string $page_template
 *
 * @property-read array  $ancestors
 * @property-read int    $post_category
 * @property-read string $tag_input
 *
 */
final class WP_Post {

        /**
         * Post ID.
         *
         * @var int
         */
        public $ID;

        /**
         * ID of post author.
         *
         * A numeric string, for compatibility reasons.
         *
         * @var string
         */
        public $post_author = 0;

        /**
         * The post's local publication time.
         *
         * @var string
         */
        public $post_date = '0000-00-00 00:00:00';

        /**
         * The post's GMT publication time.
         *
         * @var string
         */
        public $post_date_gmt = '0000-00-00 00:00:00';

        /**
         * The post's content.
         *
         * @var string
         */
        public $post_content = '';

        /**
         * The post's title.
         *
         * @var string
         */
        public $post_title = '';

        /**
         * The post's excerpt.
         *
         * @var string
         */
        public $post_excerpt = '';

        /**
         * The post's status.
         *
         * @var string
         */
        public $post_status = 'publish';

        /**
         * Whether comments are allowed.
         *
         * @var string
         */
        public $comment_status = 'open';

        /**
         * Whether pings are allowed.
         *
         * @var string
         */
        public $ping_status = 'open';

        /**
         * The post's password in plain text.
         *
         * @var string
         */
        public $post_password = '';

        /**
         * The post's slug.
         *
         * @var string
         */
        public $post_name = '';

        /**
         * URLs queued to be pinged.
         *
         * @var string
         */
        public $to_ping = '';

        /**
         * URLs that have been pinged.
         *
         * @var string
         */
        public $pinged = '';

        /**
         * The post's local modified time.
         *
         * @var string
         */
        public $post_modified = '0000-00-00 00:00:00';

        /**
         * The post's GMT modified time.
         *
         * @var string
         */
        public $post_modified_gmt = '0000-00-00 00:00:00';

        /**
         * A utility DB field for post content.
         *
         *
         * @var string
         */
        public $post_content_filtered = '';

        /**
         * ID of a post's parent post.
         *
         * @var int
         */
        public $post_parent = 0;

        /**
         * The unique identifier for a post, not necessarily a URL, used as the feed GUID.
         *
         * @var string
         */
        public $guid = '';

        /**
         * A field used for ordering posts.
         *
         * @var int
         */
        public $menu_order = 0;

        /**
         * The post's type, like post or page.
         *
         * @var string
         */
        public $post_type = 'post';

        /**
         * An attachment's mime type.
         *
         * @var string
         */
        public $post_mime_type = '';

        /**
         * Cached comment count.
         *
         * A numeric string, for compatibility reasons.
         *
         * @var string
         */
        public $comment_count = 0;

        /**
         * Stores the post object's sanitization level.
         *
         * Does not correspond to a DB field.
         *
         * @var string
         */
        public $filter;

        /**
         * Retrieve WP_Post instance.
         *
         * @static
         * @access public
         *
         * @global wpdb $wpdb
         *
         * @param int $post_id Post ID.
         * @return WP_Post|false Post object, false otherwise.
         */
        public static function get_instance( $post_id ) {
                global $wpdb;

                $post_id = (int) $post_id;
                if ( ! $post_id )
                        return false;

                $_post = wp_cache_get( $post_id, 'posts' );

                if ( ! $_post ) {
                        $_post = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE ID = %d LIMIT 1", $post_id ) );

                        if ( ! $_post )
                                return false;

                        $_post = sanitize_post( $_post, 'raw' );
                        wp_cache_add( $_post->ID, $_post, 'posts' );
                } elseif ( empty( $_post->filter ) ) {
                        $_post = sanitize_post( $_post, 'raw' );
                }

                return new WP_Post( $_post );
        }

        /**
         * Constructor.
         *
         * @param WP_Post|object $post Post object.
         */
        public function __construct( $post ) {
                foreach ( get_object_vars( $post ) as $key => $value )
                        $this->$key = $value;
        }

        /**
         * Isset-er.
         *
         * @param string $key Property to check if set.
         * @return bool
         */
        public function __isset( $key ) {
                if ( 'ancestors' == $key )
                        return true;

                if ( 'page_template' == $key )
                        return ( 'page' == $this->post_type );

                if ( 'post_category' == $key )
                   return true;

                if ( 'tags_input' == $key )
                   return true;

                return metadata_exists( 'post', $this->ID, $key );
        }

        /**
         * Getter.
         *
         * @param string $key Key to get.
         * @return mixed
         */
        public function __get( $key ) {
                if ( 'page_template' == $key && $this->__isset( $key ) ) {
                        return get_post_meta( $this->ID, '_wp_page_template', true );
                }

                if ( 'post_category' == $key ) {
                        if ( is_object_in_taxonomy( $this->post_type, 'category' ) )
                                $terms = get_the_terms( $this, 'category' );

                        if ( empty( $terms ) )
                                return array();

                        return wp_list_pluck( $terms, 'term_id' );
                }

                if ( 'tags_input' == $key ) {
                        if ( is_object_in_taxonomy( $this->post_type, 'post_tag' ) )
                                $terms = get_the_terms( $this, 'post_tag' );

                        if ( empty( $terms ) )
                                return array();

                        return wp_list_pluck( $terms, 'name' );
                }

                // Rest of the values need filtering.
                if ( 'ancestors' == $key )
                        $value = get_post_ancestors( $this );
                else
                        $value = get_post_meta( $this->ID, $key, true );

                if ( $this->filter )
                        $value = sanitize_post_field( $key, $value, $this->ID, $this->filter );

                return $value;
        }

        /**
         * {@Missing Summary}
         *
         * @param string $filter Filter.
         * @return self|array|bool|object|WP_Post
         */
        public function filter( $filter ) {
                if ( $this->filter == $filter )
                        return $this;

                if ( $filter == 'raw' )
                        return self::get_instance( $this->ID );

                return sanitize_post( $this, $filter );
        }

        /**
         * Convert object to array.
         *
         * @return array Object as array.
         */
        public function to_array() {
                $post = get_object_vars( $this );

                foreach ( array( 'ancestors', 'page_template', 'post_category', 'tags_input' ) as $key ) {
                        if ( $this->__isset( $key ) )
                                $post[ $key ] = $this->__get( $key );
                }

                return $post;
        }
}

/**
 * Retrieve ancestors of a post.
 *
 * @since 2.5.0
 *
 * @param int|WP_Post $post Post ID or post object.
 * @return array Ancestor IDs or empty array if none are found.
 */
function get_post_ancestors( $post ) {
        $post = get_post( $post );

        if ( ! $post || empty( $post->post_parent ) || $post->post_parent == $post->ID )
                return array();

        $ancestors = array();

        $id = $ancestors[] = $post->post_parent;

        while ( $ancestor = get_post( $id ) ) {
                // Loop detection: If the ancestor has been seen before, break.
                if ( empty( $ancestor->post_parent ) || ( $ancestor->post_parent == $post->ID ) || in_array( $ancestor->post_parent, $ancestors ) )
                        break;

                $id = $ancestors[] = $ancestor->post_parent;
        }

        return $ancestors;
}

/**
 * Retrieve data from a post field based on Post ID.
 *
 * Examples of the post field will be, 'post_type', 'post_status', 'post_content',
 * etc and based off of the post object property or key names.
 *
 * The context values are based off of the taxonomy filter functions and
 * supported values are found within those functions.
 *
 * @since 2.3.0
 *
 * @see sanitize_post_field()
 *
 * @param string      $field   Post field name.
 * @param int|WP_Post $post    Post ID or post object.
 * @param string      $context Optional. How to filter the field. Accepts 'raw', 'edit', 'db',
 *                             or 'display'. Default 'display'.
 * @return string The value of the post field on success, empty string on failure.
 */
function get_post_field( $field, $post, $context = 'display' ) {
        $post = get_post( $post );

        if ( !$post )
                return '';

        if ( !isset($post->$field) )
                return '';

        return sanitize_post_field($field, $post->$field, $post->ID, $context);
}

/**
 * Retrieve the mime type of an attachment based on the ID.
 *
 * This function can be used with any post type, but it makes more sense with
 * attachments.
 *
 * @since 2.0.0
 *
 * @param int|WP_Post $ID Optional. Post ID or post object. Default empty.
 * @return string|false The mime type on success, false on failure.
 */
function get_post_mime_type( $ID = '' ) {
        $post = get_post($ID);

        if ( is_object($post) )
                return $post->post_mime_type;

        return false;
}

/**
 * Retrieve the post status based on the Post ID.
 *
 * If the post ID is of an attachment, then the parent post status will be given
 * instead.
 *
 * @since 2.0.0
 *
 * @param int|WP_Post $ID Optional. Post ID or post object. Default empty.
 * @return string|false Post status on success, false on failure.
 */
function get_post_status( $ID = '' ) {
        $post = get_post($ID);

        if ( !is_object($post) )
                return false;

        if ( 'attachment' == $post->post_type ) {
                if ( 'private' == $post->post_status )
                        return 'private';

                // Unattached attachments are assumed to be published.
                if ( ( 'inherit' == $post->post_status ) && ( 0 == $post->post_parent) )
                        return 'publish';

                // Inherit status from the parent.
                if ( $post->post_parent && ( $post->ID != $post->post_parent ) ) {
                        $parent_post_status = get_post_status( $post->post_parent );
                        if ( 'trash' == $parent_post_status ) {
                                return get_post_meta( $post->post_parent, '_wp_trash_meta_status', true );
                        } else {
                                return $parent_post_status;
                        }
                }

        }

        return $post->post_status;
}

/**
 * Retrieve all of the WordPress supported post statuses.
 *
 * Posts have a limited set of valid status values, this provides the
 * post_status values and descriptions.
 *
 * @since 2.5.0
 *
 * @return array List of post statuses.
 */
function get_post_statuses() {
        $status = array(
                'draft'   => __( 'Draft' ),
                'pending' => __( 'Pending Review' ),
                'private' => __( 'Private' ),
                'publish' => __( 'Published' )
        );

        return $status;
}

/**
 * Retrieve all of the WordPress support page statuses.
 *
 * Pages have a limited set of valid status values, this provides the
 * post_status values and descriptions.
 *
 * @since 2.5.0
 *
 * @return array List of page statuses.
 */
function get_page_statuses() {
        $status = array(
                'draft'   => __( 'Draft' ),
                'private' => __( 'Private' ),
                'publish' => __( 'Published' )
        );

        return $status;
}

/**
 * Register a post status. Do not use before init.
 *
 * A simple function for creating or modifying a post status based on the
 * parameters given. The function will accept an array (second optional
 * parameter), along with a string for the post status name.
 *
 * Arguments prefixed with an _underscore shouldn't be used by plugins and themes.
 *
 * @since 3.0.0
 * @global array $wp_post_statuses Inserts new post status object into the list
 *
 * @param string $post_status Name of the post status.
 * @param array|string $args {
 *     Optional. Array or string of post status arguments.
 *
 *     @type bool|string $label                     A descriptive name for the post status marked
 *                                                  for translation. Defaults to value of $post_status.
 *     @type bool|array  $label_count               Descriptive text to use for nooped plurals.
 *                                                  Default array of $label, twice
 *     @type bool        $exclude_from_search       Whether to exclude posts with this post status
 *                                                  from search results. Default is value of $internal.
 *     @type bool        $_builtin                  Whether the status is built-in. Core-use only.
 *                                                  Default false.
 *     @type bool        $public                    Whether posts of this status should be shown
 *                                                  in the front end of the site. Default false.
 *     @type bool        $internal                  Whether the status is for internal use only.
 *                                                  Default false.
 *     @type bool        $protected                 Whether posts with this status should be protected.
 *                                                  Default false.
 *     @type bool        $private                   Whether posts with this status should be private.
 *                                                  Default false.
 *     @type bool        $publicly_queryable        Whether posts with this status should be publicly-
 *                                                  queryable. Default is value of $public.
 *     @type bool        $show_in_admin_all_list    Whether to include posts in the edit listing for
 *                                                  their post type. Default is value of $internal.
 *     @type bool        $show_in_admin_status_list Show in the list of statuses with post counts at
 *                                                  the top of the edit listings,
 *                                                  e.g. All (12) | Published (9) | My Custom Status (2)
 *                                                  Default is value of $internal.
 * }
 * @return object
 */
function register_post_status( $post_status, $args = array() ) {
        global $wp_post_statuses;

        if (!is_array($wp_post_statuses))
                $wp_post_statuses = array();

        // Args prefixed with an underscore are reserved for internal use.
        $defaults = array(
                'label' => false,
                'label_count' => false,
                'exclude_from_search' => null,
                '_builtin' => false,
                'public' => null,
                'internal' => null,
                'protected' => null,
                'private' => null,
                'publicly_queryable' => null,
                'show_in_admin_status_list' => null,
                'show_in_admin_all_list' => null,
        );
        $args = wp_parse_args($args, $defaults);
        $args = (object) $args;

        $post_status = sanitize_key($post_status);
        $args->name = $post_status;

        // Set various defaults.
        if ( null === $args->public && null === $args->internal && null === $args->protected && null === $args->private )
                $args->internal = true;

        if ( null === $args->public  )
                $args->public = false;

        if ( null === $args->private  )
                $args->private = false;

        if ( null === $args->protected  )
                $args->protected = false;

        if ( null === $args->internal  )
                $args->internal = false;

        if ( null === $args->publicly_queryable )
                $args->publicly_queryable = $args->public;

        if ( null === $args->exclude_from_search )
                $args->exclude_from_search = $args->internal;

        if ( null === $args->show_in_admin_all_list )
                $args->show_in_admin_all_list = !$args->internal;

        if ( null === $args->show_in_admin_status_list )
                $args->show_in_admin_status_list = !$args->internal;

        if ( false === $args->label )
                $args->label = $post_status;

        if ( false === $args->label_count )
                $args->label_count = array( $args->label, $args->label );

        $wp_post_statuses[$post_status] = $args;

        return $args;
}

/**
 * Retrieve a post status object by name.
 *
 * @since 3.0.0
 *
 * @global array $wp_post_statuses List of post statuses.
 *
 * @see register_post_status()
 *
 * @param string $post_status The name of a registered post status.
 * @return object|null A post status object.
 */
function get_post_status_object( $post_status ) {
        global $wp_post_statuses;

        if ( empty($wp_post_statuses[$post_status]) )
                return null;

        return $wp_post_statuses[$post_status];
}

/**
 * Get a list of post statuses.
 *
 * @since 3.0.0
 *
 * @global array $wp_post_statuses List of post statuses.
 *
 * @see register_post_status()
 *
 * @param array|string $args     Optional. Array or string of post status arguments to compare against
 *                               properties of the global `$wp_post_statuses objects`. Default empty array.
 * @param string       $output   Optional. The type of output to return, either 'names' or 'objects'. Default 'names'.
 * @param string       $operator Optional. The logical operation to perform. 'or' means only one element
 *                               from the array needs to match; 'and' means all elements must match.
 *                               Default 'and'.
 * @return array A list of post status names or objects.
 */
function get_post_stati( $args = array(), $output = 'names', $operator = 'and' ) {
        global $wp_post_statuses;

        $field = ('names' == $output) ? 'name' : false;

        return wp_filter_object_list($wp_post_statuses, $args, $operator, $field);
}

/**
 * Whether the post type is hierarchical.
 *
 * A false return value might also mean that the post type does not exist.
 *
 * @since 3.0.0
 *
 * @see get_post_type_object()
 *
 * @param string $post_type Post type name
 * @return bool Whether post type is hierarchical.
 */
function is_post_type_hierarchical( $post_type ) {
        if ( ! post_type_exists( $post_type ) )
                return false;

        $post_type = get_post_type_object( $post_type );
        return $post_type->hierarchical;
}

/**
 * Check if a post type is registered.
 *
 * @since 3.0.0
 *
 * @see get_post_type_object()
 *
 * @param string $post_type Post type name.
 * @return bool Whether post type is registered.
 */
function post_type_exists( $post_type ) {
        return (bool) get_post_type_object( $post_type );
}

/**
 * Retrieve the post type of the current post or of a given post.
 *
 * @since 2.1.0
 *
 * @param int|WP_Post|null $post Optional. Post ID or post object. Default is global $post.
 * @return string|false          Post type on success, false on failure.
 */
function get_post_type( $post = null ) {
        if ( $post = get_post( $post ) )
                return $post->post_type;

        return false;
}

/**
 * Retrieve a post type object by name.
 *
 * @since 3.0.0
 *
 * @global array $wp_post_types List of post types.
 *
 * @see register_post_type()
 *
 * @param string $post_type The name of a registered post type.
 * @return object|null A post type object.
 */
function get_post_type_object( $post_type ) {
        global $wp_post_types;

        if ( empty($wp_post_types[$post_type]) )
                return null;

        return $wp_post_types[$post_type];
}

/**
 * Get a list of all registered post type objects.
 *
 * @since 2.9.0
 *
 * @global array $wp_post_types List of post types.
 *
 * @see register_post_type() for accepted arguments.
 *
 * @param array|string $args     Optional. An array of key => value arguments to match against
 *                               the post type objects. Default empty array.
 * @param string       $output   Optional. The type of output to return. Accepts post type 'names'
 *                               or 'objects'. Default 'names'.
 * @param string       $operator Optional. The logical operation to perform. 'or' means only one
 *                               element from the array needs to match; 'and' means all elements
 *                               must match. Accepts 'or' or 'and'. Default 'and'.
 * @return array A list of post type names or objects.
 */
function get_post_types( $args = array(), $output = 'names', $operator = 'and' ) {
        global $wp_post_types;

        $field = ('names' == $output) ? 'name' : false;

        return wp_filter_object_list($wp_post_types, $args, $operator, $field);
}

/**
 * Register a post type. Do not use before init.
 *
 * A function for creating or modifying a post type based on the
 * parameters given. The function will accept an array (second optional
 * parameter), along with a string for the post type name.
 *
 * @since 2.9.0
 *
 * @global array      $wp_post_types List of post types.
 * @global WP_Rewrite $wp_rewrite    Used for default feeds.
 * @global WP         $wp            Used to add query vars.
 *
 * @param string $post_type Post type key, must not exceed 20 characters.
 * @param array|string $args {
 *     Array or string of arguments for registering a post type.
 *
 *     @type string      $label                Name of the post type shown in the menu. Usually plural.
 *                                             Default is value of $labels['name'].
 *     @type array       $labels               An array of labels for this post type. If not set, post
 *                                             labels are inherited for non-hierarchical types and page
 *                                             labels for hierarchical ones. {@see get_post_type_labels()}.
 *     @type string      $description          A short descriptive summary of what the post type is.
 *                                             Default empty.
 *     @type bool        $public               Whether a post type is intended for use publicly either via
 *                                             the admin interface or by front-end users. While the default
 *                                             settings of $exclude_from_search, $publicly_queryable, $show_ui,
 *                                             and $show_in_nav_menus are inherited from public, each does not
 *                                             rely on this relationship and controls a very specific intention.
 *                                             Default false.
 *     @type bool        $hierarchical         Whether the post type is hierarchical (e.g. page). Default false.
 *     @type bool        $exclude_from_search  Whether to exclude posts with this post type from front end search
 *                                             results. Default is the opposite value of $public.
 *     @type bool        $publicly_queryable   Whether queries can be performed on the front end for the post type
 *                                             as part of {@see parse_request()}. Endpoints would include:
 *                                             * ?post_type={post_type_key}
 *                                             * ?{post_type_key}={single_post_slug}
 *                                             * ?{post_type_query_var}={single_post_slug}
 *                                             If not set, the default is inherited from $public.
 *     @type bool        $show_ui              Whether to generate a default UI for managing this post type in the
 *                                             admin. Default is value of $public.
 *     @type bool        $show_in_menu         Where to show the post type in the admin menu. To work, $show_ui
 *                                             must be true. If true, the post type is shown in its own top level
 *                                             menu. If false, no menu is shown. If a string of an existing top
 *                                             level menu (eg. 'tools.php' or 'edit.php?post_type=page'), the post
 *                                             type will be placed as a sub-menu of that.
 *                                             Default is value of $show_ui.
 *     @type bool        $show_in_nav_menus    Makes this post type available for selection in navigation menus.
 *                                             Default is value $public.
 *     @type bool        $show_in_admin_bar    Makes this post type available via the admin bar. Default is value
 *                                             of $show_in_menu.
 *     @type int         $menu_position        The position in the menu order the post type should appear. To work,
 *                                             $show_in_menu must be true. Default null (at the bottom).
 *     @type string      $menu_icon            The url to the icon to be used for this menu. Pass a base64-encoded
 *                                             SVG using a data URI, which will be colored to match the color scheme
 *                                             -- this should begin with 'data:image/svg+xml;base64,'. Pass the name
 *                                             of a Dashicons helper class to use a font icon, e.g.
 *                                             'dashicons-chart-pie'. Pass 'none' to leave div.wp-menu-image empty
 *                                             so an icon can be added via CSS. Defaults to use the posts icon.
 *     @type string      $capability_type      The string to use to build the read, edit, and delete capabilities.
 *                                             May be passed as an array to allow for alternative plurals when using
 *                                             this argument as a base to construct the capabilities, e.g.
 *                                             array('story', 'stories'). Default 'post'.
 *     @type array       $capabilities         Array of capabilities for this post type. $capability_type is used
 *                                             as a base to construct capabilities by default.
 *                                             {@see get_post_type_capabilities()}.
 *     @type bool        $map_meta_cap         Whether to use the internal default meta capability handling.
 *                                             Default false.
 *     @type array       $supports             An alias for calling {@see add_post_type_support()} directly.
 *                                             Defaults to array containing 'title' & 'editor'.
 *     @type callback    $register_meta_box_cb Provide a callback function that sets up the meta boxes for the
 *                                             edit form. Do remove_meta_box() and add_meta_box() calls in the
 *                                             callback. Default null.
 *     @type array       $taxonomies           An array of taxonomy identifiers that will be registered for the
 *                                             post type. Taxonomies can be registered later with
 *                                             {@see register_taxonomy()} or {@see register_taxonomy_for_object_type()}.
 *                                             Default empty array.
 *     @type bool|string $has_archive          Whether there should be post type archives, or if a string, the
 *                                             archive slug to use. Will generate the proper rewrite rules if
 *                                             $rewrite is enabled. Default false.
 *     @type bool|array  $rewrite              {
 *         Triggers the handling of rewrites for this post type. To prevent rewrite, set to false.
 *         Defaults to true, using $post_type as slug. To specify rewrite rules, an array can be
 *         passed with any of these keys:
 *
 *         @type string $slug       Customize the permastruct slug. Defaults to $post_type key.
 *         @type bool   $with_front Whether the permastruct should be prepended with WP_Rewrite::$front.
 *                                  Default true.
 *         @type bool   $feeds      Whether the feed permastruct should be built for this post type.
 *                                  Default is value of $has_archive.
 *         @type bool   $pages      Whether the permastruct should provide for pagination. Default true.
 *         @type const  $ep_mask    Endpoint mask to assign. If not specified and permalink_epmask is set,
 *                                  inherits from $permalink_epmask. If not specified and permalink_epmask
 *                                  is not set, defaults to EP_PERMALINK.
 *     }
 *     @type string|bool $query_var            Sets the query_var key for this post type. Defaults to $post_type
 *                                             key. If false, a post type cannot be loaded at
 *                                             ?{query_var}={post_slug}. If specified as a string, the query
 *                                             ?{query_var_string}={post_slug} will be valid.
 *     @type bool        $can_export           Whether to allow this post type to be exported. Default true.
 *     @type bool        $delete_with_user     Whether to delete posts of this type when deleting a user. If true,
 *                                             posts of this type belonging to the user will be moved to trash
 *                                             when then user is deleted. If false, posts of this type belonging
 *                                             to the user will *not* be trashed or deleted. If not set (the default),
 *                                             posts are trashed if post_type_supports('author'). Otherwise posts
 *                                             are not trashed or deleted. Default null.
 *     @type bool        $_builtin             FOR INTERNAL USE ONLY! True if this post type is a native or
 *                                             "built-in" post_type. Default false.
 *     @type string      $_edit_link           FOR INTERNAL USE ONLY! URL segment to use for edit link of
 *                                             this post type. Default 'post.php?post=%d'.
 * }
 * @return object|WP_Error The registered post type object, or an error object.
 */
function register_post_type( $post_type, $args = array() ) {
        global $wp_post_types, $wp_rewrite, $wp;

        if ( ! is_array( $wp_post_types ) )
                $wp_post_types = array();

        // Args prefixed with an underscore are reserved for internal use.
        $defaults = array(
                'labels'               => array(),
                'description'          => '',
                'public'               => false,
                'hierarchical'         => false,
                'exclude_from_search'  => null,
                'publicly_queryable'   => null,
                'show_ui'              => null,
                'show_in_menu'         => null,
                'show_in_nav_menus'    => null,
                'show_in_admin_bar'    => null,
                'menu_position'        => null,
                'menu_icon'            => null,
                'capability_type'      => 'post',
                'capabilities'         => array(),
                'map_meta_cap'         => null,
                'supports'             => array(),
                'register_meta_box_cb' => null,
                'taxonomies'           => array(),
                'has_archive'          => false,
                'rewrite'              => true,
                'query_var'            => true,
                'can_export'           => true,
                'delete_with_user'     => null,
                '_builtin'             => false,
                '_edit_link'           => 'post.php?post=%d',
        );
        $args = wp_parse_args( $args, $defaults );
        $args = (object) $args;

        $post_type = sanitize_key( $post_type );
        $args->name = $post_type;

        if ( empty( $post_type ) || strlen( $post_type ) > 20 ) {
                _doing_it_wrong( __FUNCTION__, __( 'Post type names must be between 1 and 20 characters in length.' ), '4.2' );
                return new WP_Error( 'post_type_length_invalid', __( 'Post type names must be between 1 and 20 characters in length.' ) );
        }

        // If not set, default to the setting for public.
        if ( null === $args->publicly_queryable )
                $args->publicly_queryable = $args->public;

        // If not set, default to the setting for public.
        if ( null === $args->show_ui )
                $args->show_ui = $args->public;

        // If not set, default to the setting for show_ui.
        if ( null === $args->show_in_menu || ! $args->show_ui )
                $args->show_in_menu = $args->show_ui;

        // If not set, default to the whether the full UI is shown.
        if ( null === $args->show_in_admin_bar )
                $args->show_in_admin_bar = (bool) $args->show_in_menu;

        // If not set, default to the setting for public.
        if ( null === $args->show_in_nav_menus )
                $args->show_in_nav_menus = $args->public;

        // If not set, default to true if not public, false if public.
        if ( null === $args->exclude_from_search )
                $args->exclude_from_search = !$args->public;

        // Back compat with quirky handling in version 3.0. #14122.
        if ( empty( $args->capabilities ) && null === $args->map_meta_cap && in_array( $args->capability_type, array( 'post', 'page' ) ) )
                $args->map_meta_cap = true;

        // If not set, default to false.
        if ( null === $args->map_meta_cap )
                $args->map_meta_cap = false;

        $args->cap = get_post_type_capabilities( $args );
        unset( $args->capabilities );

        if ( is_array( $args->capability_type ) )
                $args->capability_type = $args->capability_type[0];

        if ( ! empty( $args->supports ) ) {
                add_post_type_support( $post_type, $args->supports );
                unset( $args->supports );
        } elseif ( false !== $args->supports ) {
                // Add default features
                add_post_type_support( $post_type, array( 'title', 'editor' ) );
        }

        if ( false !== $args->query_var && ! empty( $wp ) ) {
                if ( true === $args->query_var )
                        $args->query_var = $post_type;
                else
                        $args->query_var = sanitize_title_with_dashes( $args->query_var );
                $wp->add_query_var( $args->query_var );
        }

        if ( false !== $args->rewrite && ( is_admin() || '' != get_option( 'permalink_structure' ) ) ) {
                if ( ! is_array( $args->rewrite ) )
                        $args->rewrite = array();
                if ( empty( $args->rewrite['slug'] ) )
                        $args->rewrite['slug'] = $post_type;
                if ( ! isset( $args->rewrite['with_front'] ) )
                        $args->rewrite['with_front'] = true;
                if ( ! isset( $args->rewrite['pages'] ) )
                        $args->rewrite['pages'] = true;
                if ( ! isset( $args->rewrite['feeds'] ) || ! $args->has_archive )
                        $args->rewrite['feeds'] = (bool) $args->has_archive;
                if ( ! isset( $args->rewrite['ep_mask'] ) ) {
                        if ( isset( $args->permalink_epmask ) )
                                $args->rewrite['ep_mask'] = $args->permalink_epmask;
                        else
                                $args->rewrite['ep_mask'] = EP_PERMALINK;
                }

                if ( $args->hierarchical )
                        add_rewrite_tag( "%$post_type%", '(.+?)', $args->query_var ? "{$args->query_var}=" : "post_type=$post_type&pagename=" );
                else
                        add_rewrite_tag( "%$post_type%", '([^/]+)', $args->query_var ? "{$args->query_var}=" : "post_type=$post_type&name=" );

                if ( $args->has_archive ) {
                        $archive_slug = $args->has_archive === true ? $args->rewrite['slug'] : $args->has_archive;
                        if ( $args->rewrite['with_front'] )
                                $archive_slug = substr( $wp_rewrite->front, 1 ) . $archive_slug;
                        else
                                $archive_slug = $wp_rewrite->root . $archive_slug;

                        add_rewrite_rule( "{$archive_slug}/?$", "index.php?post_type=$post_type", 'top' );
                        if ( $args->rewrite['feeds'] && $wp_rewrite->feeds ) {
                                $feeds = '(' . trim( implode( '|', $wp_rewrite->feeds ) ) . ')';
                                add_rewrite_rule( "{$archive_slug}/feed/$feeds/?$", "index.php?post_type=$post_type" . '&feed=$matches[1]', 'top' );
                                add_rewrite_rule( "{$archive_slug}/$feeds/?$", "index.php?post_type=$post_type" . '&feed=$matches[1]', 'top' );
                        }
                        if ( $args->rewrite['pages'] )
                                add_rewrite_rule( "{$archive_slug}/{$wp_rewrite->pagination_base}/([0-9]{1,})/?$", "index.php?post_type=$post_type" . '&paged=$matches[1]', 'top' );
                }

                $permastruct_args = $args->rewrite;
                $permastruct_args['feed'] = $permastruct_args['feeds'];
                add_permastruct( $post_type, "{$args->rewrite['slug']}/%$post_type%", $permastruct_args );
        }

        // Register the post type meta box if a custom callback was specified.
        if ( $args->register_meta_box_cb )
                add_action( 'add_meta_boxes_' . $post_type, $args->register_meta_box_cb, 10, 1 );

        $args->labels = get_post_type_labels( $args );
        $args->label = $args->labels->name;

        $wp_post_types[ $post_type ] = $args;

        add_action( 'future_' . $post_type, '_future_post_hook', 5, 2 );

        foreach ( $args->taxonomies as $taxonomy ) {
                register_taxonomy_for_object_type( $taxonomy, $post_type );
        }

        /**
         * Fires after a post type is registered.
         *
         * @since 3.3.0
         *
         * @param string $post_type Post type.
         * @param object $args      Arguments used to register the post type.
         */
        do_action( 'registered_post_type', $post_type, $args );

        return $args;
}

/**
 * Build an object with all post type capabilities out of a post type object
 *
 * Post type capabilities use the 'capability_type' argument as a base, if the
 * capability is not set in the 'capabilities' argument array or if the
 * 'capabilities' argument is not supplied.
 *
 * The capability_type argument can optionally be registered as an array, with
 * the first value being singular and the second plural, e.g. array('story, 'stories')
 * Otherwise, an 's' will be added to the value for the plural form. After
 * registration, capability_type will always be a string of the singular value.
 *
 * By default, seven keys are accepted as part of the capabilities array:
 *
 * - edit_post, read_post, and delete_post are meta capabilities, which are then
 *   generally mapped to corresponding primitive capabilities depending on the
 *   context, which would be the post being edited/read/deleted and the user or
 *   role being checked. Thus these capabilities would generally not be granted
 *   directly to users or roles.
 *
 * - edit_posts - Controls whether objects of this post type can be edited.
 * - edit_others_posts - Controls whether objects of this type owned by other users
 *   can be edited. If the post type does not support an author, then this will
 *   behave like edit_posts.
 * - publish_posts - Controls publishing objects of this post type.
 * - read_private_posts - Controls whether private objects can be read.
 *
 * These four primitive capabilities are checked in core in various locations.
 * There are also seven other primitive capabilities which are not referenced
 * directly in core, except in map_meta_cap(), which takes the three aforementioned
 * meta capabilities and translates them into one or more primitive capabilities
 * that must then be checked against the user or role, depending on the context.
 *
 * - read - Controls whether objects of this post type can be read.
 * - delete_posts - Controls whether objects of this post type can be deleted.
 * - delete_private_posts - Controls whether private objects can be deleted.
 * - delete_published_posts - Controls whether published objects can be deleted.
 * - delete_others_posts - Controls whether objects owned by other users can be
 *   can be deleted. If the post type does not support an author, then this will
 *   behave like delete_posts.
 * - edit_private_posts - Controls whether private objects can be edited.
 * - edit_published_posts - Controls whether published objects can be edited.
 *
 * These additional capabilities are only used in map_meta_cap(). Thus, they are
 * only assigned by default if the post type is registered with the 'map_meta_cap'
 * argument set to true (default is false).
 *
 * @since 3.0.0
 *
 * @see register_post_type()
 * @see map_meta_cap()
 *
 * @param object $args Post type registration arguments.
 * @return object object with all the capabilities as member variables.
 */
function get_post_type_capabilities( $args ) {
        if ( ! is_array( $args->capability_type ) )
                $args->capability_type = array( $args->capability_type, $args->capability_type . 's' );

        // Singular base for meta capabilities, plural base for primitive capabilities.
        list( $singular_base, $plural_base ) = $args->capability_type;

        $default_capabilities = array(
                // Meta capabilities
                'edit_post'          => 'edit_'         . $singular_base,
                'read_post'          => 'read_'         . $singular_base,
                'delete_post'        => 'delete_'       . $singular_base,
                // Primitive capabilities used outside of map_meta_cap():
                'edit_posts'         => 'edit_'         . $plural_base,
                'edit_others_posts'  => 'edit_others_'  . $plural_base,
                'publish_posts'      => 'publish_'      . $plural_base,
                'read_private_posts' => 'read_private_' . $plural_base,
        );

        // Primitive capabilities used within map_meta_cap():
        if ( $args->map_meta_cap ) {
                $default_capabilities_for_mapping = array(
                        'read'                   => 'read',
                        'delete_posts'           => 'delete_'           . $plural_base,
                        'delete_private_posts'   => 'delete_private_'   . $plural_base,
                        'delete_published_posts' => 'delete_published_' . $plural_base,
                        'delete_others_posts'    => 'delete_others_'    . $plural_base,
                        'edit_private_posts'     => 'edit_private_'     . $plural_base,
                        'edit_published_posts'   => 'edit_published_'   . $plural_base,
                );
                $default_capabilities = array_merge( $default_capabilities, $default_capabilities_for_mapping );
        }

        $capabilities = array_merge( $default_capabilities, $args->capabilities );

        // Post creation capability simply maps to edit_posts by default:
        if ( ! isset( $capabilities['create_posts'] ) )
                $capabilities['create_posts'] = $capabilities['edit_posts'];

        // Remember meta capabilities for future reference.
        if ( $args->map_meta_cap )
                _post_type_meta_capabilities( $capabilities );

        return (object) $capabilities;
}

/**
 * Store or return a list of post type meta caps for map_meta_cap().
 *
 * @since 3.1.0
 * @access private
 *
 * @staticvar array $meta_caps
 *
 * @param array|void $capabilities Post type meta capabilities.
 */
function _post_type_meta_capabilities( $capabilities = null ) {
        static $meta_caps = array();
        if ( null === $capabilities )
                return $meta_caps;
        foreach ( $capabilities as $core => $custom ) {
                if ( in_array( $core, array( 'read_post', 'delete_post', 'edit_post' ) ) )
                        $meta_caps[ $custom ] = $core;
        }
}

/**
 * Build an object with all post type labels out of a post type object
 *
 * Accepted keys of the label array in the post type object:
 *
 * - name - general name for the post type, usually plural. The same and overridden
 *          by $post_type_object->label. Default is Posts/Pages
 * - singular_name - name for one object of this post type. Default is Post/Page
 * - add_new - Default is Add New for both hierarchical and non-hierarchical types.
 *             When internationalizing this string, please use a gettext context
 *             {@link https://codex.wordpress.org/I18n_for_WordPress_Developers#Disambiguation_by_context}
 *             matching your post type. Example: `_x( 'Add New', 'product' );`.
 * - add_new_item - Default is Add New Post/Add New Page.
 * - edit_item - Default is Edit Post/Edit Page.
 * - new_item - Default is New Post/New Page.
 * - view_item - Default is View Post/View Page.
 * - search_items - Default is Search Posts/Search Pages.
 * - not_found - Default is No posts found/No pages found.
 * - not_found_in_trash - Default is No posts found in Trash/No pages found in Trash.
 * - parent_item_colon - This string isn't used on non-hierarchical types. In hierarchical
 *                       ones the default is 'Parent Page:'.
 * - all_items - String for the submenu. Default is All Posts/All Pages.
 * - featured_image - Default is Featured Image.
 * - set_featured_image - Default is Set featured image.
 * - remove_featured_image - Default is Remove featured image.
 * - use_featured_image - Default is Use as featured image.
 * - menu_name - Default is the same as `name`.
 *
 * Above, the first default value is for non-hierarchical post types (like posts)
 * and the second one is for hierarchical post types (like pages).
 *
 * @since 3.0.0
 * @since 4.3.0 Added the `featured_image`, `set_featured_image`, `remove_featured_image`,
 *              and `use_featured_image` labels.
 * @access private
 *
 * @param object $post_type_object Post type object.
 * @return object object with all the labels as member variables.
 */
function get_post_type_labels( $post_type_object ) {
        $nohier_vs_hier_defaults = array(
                'name' => array( _x('Posts', 'post type general name'), _x('Pages', 'post type general name') ),
                'singular_name' => array( _x('Post', 'post type singular name'), _x('Page', 'post type singular name') ),
                'add_new' => array( _x('Add New', 'post'), _x('Add New', 'page') ),
                'add_new_item' => array( __('Add New Post'), __('Add New Page') ),
                'edit_item' => array( __('Edit Post'), __('Edit Page') ),
                'new_item' => array( __('New Post'), __('New Page') ),
                'view_item' => array( __('View Post'), __('View Page') ),
                'search_items' => array( __('Search Posts'), __('Search Pages') ),
                'not_found' => array( __('No posts found.'), __('No pages found.') ),
                'not_found_in_trash' => array( __('No posts found in Trash.'), __('No pages found in Trash.') ),
                'parent_item_colon' => array( null, __('Parent Page:') ),
                'all_items' => array( __( 'All Posts' ), __( 'All Pages' ) ),
                'featured_image' => array( __( 'Featured Image' ), __( 'Featured Image' ) ),
                'set_featured_image' => array( __( 'Set featured image' ), __( 'Set featured image' ) ),
                'remove_featured_image' => array( __( 'Remove featured image' ), __( 'Remove featured image' ) ),
                'use_featured_image' => array( __( 'Use as featured image' ), __( 'Use as featured image' ) ),
        );
        $nohier_vs_hier_defaults['menu_name'] = $nohier_vs_hier_defaults['name'];

        $labels = _get_custom_object_labels( $post_type_object, $nohier_vs_hier_defaults );

        $post_type = $post_type_object->name;

        /**
         * Filter the labels of a specific post type.
         *
         * The dynamic portion of the hook name, `$post_type`, refers to
         * the post type slug.
         *
         * @since 3.5.0
         *
         * @see get_post_type_labels() for the full list of labels.
         *
         * @param object $labels Object with labels for the post type as member variables.
         */
        return apply_filters( "post_type_labels_{$post_type}", $labels );
}

/**
 * Build an object with custom-something object (post type, taxonomy) labels
 * out of a custom-something object
 *
 * @since 3.0.0
 * @access private
 *
 * @param object $object                  A custom-something object.
 * @param array  $nohier_vs_hier_defaults Hierarchical vs non-hierarchical default labels.
 */
function _get_custom_object_labels( $object, $nohier_vs_hier_defaults ) {
        $object->labels = (array) $object->labels;

        if ( isset( $object->label ) && empty( $object->labels['name'] ) )
                $object->labels['name'] = $object->label;

        if ( !isset( $object->labels['singular_name'] ) && isset( $object->labels['name'] ) )
                $object->labels['singular_name'] = $object->labels['name'];

        if ( ! isset( $object->labels['name_admin_bar'] ) )
                $object->labels['name_admin_bar'] = isset( $object->labels['singular_name'] ) ? $object->labels['singular_name'] : $object->name;

        if ( !isset( $object->labels['menu_name'] ) && isset( $object->labels['name'] ) )
                $object->labels['menu_name'] = $object->labels['name'];

        if ( !isset( $object->labels['all_items'] ) && isset( $object->labels['menu_name'] ) )
                $object->labels['all_items'] = $object->labels['menu_name'];

        $defaults = array();
        foreach ( $nohier_vs_hier_defaults as $key => $value ) {
                $defaults[$key] = $object->hierarchical ? $value[1] : $value[0];
        }
        $labels = array_merge( $defaults, $object->labels );
        return (object) $labels;
}

/**
 * Add submenus for post types.
 *
 * @access private
 * @since 3.1.0
 */
function _add_post_type_submenus() {
        foreach ( get_post_types( array( 'show_ui' => true ) ) as $ptype ) {
                $ptype_obj = get_post_type_object( $ptype );
                // Sub-menus only.
                if ( ! $ptype_obj->show_in_menu || $ptype_obj->show_in_menu === true )
                        continue;
                add_submenu_page( $ptype_obj->show_in_menu, $ptype_obj->labels->name, $ptype_obj->labels->all_items, $ptype_obj->cap->edit_posts, "edit.php?post_type=$ptype" );
        }
}

/**
 * Register support of certain features for a post type.
 *
 * All core features are directly associated with a functional area of the edit
 * screen, such as the editor or a meta box. Features include: 'title', 'editor',
 * 'comments', 'revisions', 'trackbacks', 'author', 'excerpt', 'page-attributes',
 * 'thumbnail', 'custom-fields', and 'post-formats'.
 *
 * Additionally, the 'revisions' feature dictates whether the post type will
 * store revisions, and the 'comments' feature dictates whether the comments
 * count will show on the edit screen.
 *
 * @since 3.0.0
 *
 * @global array $_wp_post_type_features
 *
 * @param string       $post_type The post type for which to add the feature.
 * @param string|array $feature   The feature being added, accepts an array of
 *                                feature strings or a single string.
 */
function add_post_type_support( $post_type, $feature ) {
        global $_wp_post_type_features;

        $features = (array) $feature;
        foreach ($features as $feature) {
                if ( func_num_args() == 2 )
                        $_wp_post_type_features[$post_type][$feature] = true;
                else
                        $_wp_post_type_features[$post_type][$feature] = array_slice( func_get_args(), 2 );
        }
}

/**
 * Remove support for a feature from a post type.
 *
 * @since 3.0.0
 *
 * @global array $_wp_post_type_features
 *
 * @param string $post_type The post type for which to remove the feature.
 * @param string $feature   The feature being removed.
 */
function remove_post_type_support( $post_type, $feature ) {
        global $_wp_post_type_features;

        unset( $_wp_post_type_features[ $post_type ][ $feature ] );
}

/**
 * Get all the post type features
 *
 * @since 3.4.0
 *
 * @global array $_wp_post_type_features
 *
 * @param string $post_type The post type.
 * @return array Post type supports list.
 */
function get_all_post_type_supports( $post_type ) {
        global $_wp_post_type_features;

        if ( isset( $_wp_post_type_features[$post_type] ) )
                return $_wp_post_type_features[$post_type];

        return array();
}

/**
 * Check a post type's support for a given feature.
 *
 * @since 3.0.0
 *
 * @global array $_wp_post_type_features
 *
 * @param string $post_type The post type being checked.
 * @param string $feature   The feature being checked.
 * @return bool Whether the post type supports the given feature.
 */
function post_type_supports( $post_type, $feature ) {
        global $_wp_post_type_features;

        return ( isset( $_wp_post_type_features[$post_type][$feature] ) );
}

/**
 * Update the post type for the post ID.
 *
 * The page or post cache will be cleaned for the post ID.
 *
 * @since 2.5.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int    $post_id   Optional. Post ID to change post type. Default 0.
 * @param string $post_type Optional. Post type. Accepts 'post' or 'page' to
 *                          name a few. Default 'post'.
 * @return int|false Amount of rows changed. Should be 1 for success and 0 for failure.
 */
function set_post_type( $post_id = 0, $post_type = 'post' ) {
        global $wpdb;

        $post_type = sanitize_post_field('post_type', $post_type, $post_id, 'db');
        $return = $wpdb->update( $wpdb->posts, array('post_type' => $post_type), array('ID' => $post_id) );

        clean_post_cache( $post_id );

        return $return;
}

/**
 * Retrieve list of latest posts or posts matching criteria.
 *
 * The defaults are as follows:
 *
 * @since 1.2.0
 *
 * @see WP_Query::parse_query()
 *
 * @param array $args {
 *     Optional. Arguments to retrieve posts. {@see WP_Query::parse_query()} for more
 *     available arguments.
 *
 *     @type int        $numberposts      Total number of posts to retrieve. Is an alias of $posts_per_page
 *                                        in WP_Query. Accepts 1+ and -1 for all. Default 5.
 *     @type int        $offset           The number of posts to offset before retrieval. Default 0.
 *     @type int|string $category         Category ID or comma-separated list of IDs (this or any children).
 *                                        Is an alias of $cat in WP_Query. Default 0.
 *     @type string     $orderby          Which field to order posts by. Accepts post fields. Default 'date'.
 *     @type array      $include          An array of post IDs to retrieve, sticky posts will be included.
 *                                        Is an alias of $post__in in WP_Query. Default empty array.
 *     @type array      $exclude          An array of post IDs not to retrieve. Default empty array.
 *     @type string     $meta_key         Custom field key. Default empty.
 *     @type mixed      $meta_value       Custom field value. Default empty string.
 *     @type string     $post_type        Post type. Default 'post'.
 *     @type bool       $suppress_filters Whether to suppress filters. Default true.
 * }
 * @return array List of posts.
 */
function get_posts( $args = null ) {
        $defaults = array(
                'numberposts' => 5, 'offset' => 0,
                'category' => 0, 'orderby' => 'date',
                'order' => 'DESC', 'include' => array(),
                'exclude' => array(), 'meta_key' => '',
                'meta_value' =>'', 'post_type' => 'post',
                'suppress_filters' => true
        );

        $r = wp_parse_args( $args, $defaults );
        if ( empty( $r['post_status'] ) )
                $r['post_status'] = ( 'attachment' == $r['post_type'] ) ? 'inherit' : 'publish';
        if ( ! empty($r['numberposts']) && empty($r['posts_per_page']) )
                $r['posts_per_page'] = $r['numberposts'];
        if ( ! empty($r['category']) )
                $r['cat'] = $r['category'];
        if ( ! empty($r['include']) ) {
                $incposts = wp_parse_id_list( $r['include'] );
                $r['posts_per_page'] = count($incposts);  // only the number of posts included
                $r['post__in'] = $incposts;
        } elseif ( ! empty($r['exclude']) )
                $r['post__not_in'] = wp_parse_id_list( $r['exclude'] );

        $r['ignore_sticky_posts'] = true;
        $r['no_found_rows'] = true;

        $get_posts = new WP_Query;
        return $get_posts->query($r);

}

//
// Post meta functions
//

/**
 * Add meta data field to a post.
 *
 * Post meta data is called "Custom Fields" on the Administration Screen.
 *
 * @since 1.5.0
 *
 * @param int    $post_id    Post ID.
 * @param string $meta_key   Metadata name.
 * @param mixed  $meta_value Metadata value. Must be serializable if non-scalar.
 * @param bool   $unique     Optional. Whether the same key should not be added.
 *                           Default false.
 * @return int|false Meta ID on success, false on failure.
 */
function add_post_meta( $post_id, $meta_key, $meta_value, $unique = false ) {
        // Make sure meta is added to the post, not a revision.
        if ( $the_post = wp_is_post_revision($post_id) )
                $post_id = $the_post;

        return add_metadata('post', $post_id, $meta_key, $meta_value, $unique);
}

/**
 * Remove metadata matching criteria from a post.
 *
 * You can match based on the key, or key and value. Removing based on key and
 * value, will keep from removing duplicate metadata with the same key. It also
 * allows removing all metadata matching key, if needed.
 *
 * @since 1.5.0
 *
 * @param int    $post_id    Post ID.
 * @param string $meta_key   Metadata name.
 * @param mixed  $meta_value Optional. Metadata value. Must be serializable if
 *                           non-scalar. Default empty.
 * @return bool True on success, false on failure.
 */
function delete_post_meta( $post_id, $meta_key, $meta_value = '' ) {
        // Make sure meta is added to the post, not a revision.
        if ( $the_post = wp_is_post_revision($post_id) )
                $post_id = $the_post;

        return delete_metadata('post', $post_id, $meta_key, $meta_value);
}

/**
 * Retrieve post meta field for a post.
 *
 * @since 1.5.0
 *
 * @param int    $post_id Post ID.
 * @param string $key     Optional. The meta key to retrieve. By default, returns
 *                        data for all keys. Default empty.
 * @param bool   $single  Optional. Whether to return a single value. Default false.
 * @return mixed Will be an array if $single is false. Will be value of meta data
 *               field if $single is true.
 */
function get_post_meta( $post_id, $key = '', $single = false ) {
        return get_metadata('post', $post_id, $key, $single);
}

/**
 * Update post meta field based on post ID.
 *
 * Use the $prev_value parameter to differentiate between meta fields with the
 * same key and post ID.
 *
 * If the meta field for the post does not exist, it will be added.
 *
 * @since 1.5.0
 *
 * @param int    $post_id    Post ID.
 * @param string $meta_key   Metadata key.
 * @param mixed  $meta_value Metadata value. Must be serializable if non-scalar.
 * @param mixed  $prev_value Optional. Previous value to check before removing.
 *                           Default empty.
 * @return int|bool Meta ID if the key didn't exist, true on successful update,
 *                  false on failure.
 */
function update_post_meta( $post_id, $meta_key, $meta_value, $prev_value = '' ) {
        // Make sure meta is added to the post, not a revision.
        if ( $the_post = wp_is_post_revision($post_id) )
                $post_id = $the_post;

        return update_metadata('post', $post_id, $meta_key, $meta_value, $prev_value);
}

/**
 * Delete everything from post meta matching meta key.
 *
 * @since 2.3.0
 *
 * @param string $post_meta_key Key to search for when deleting.
 * @return bool Whether the post meta key was deleted from the database.
 */
function delete_post_meta_by_key( $post_meta_key ) {
        return delete_metadata( 'post', null, $post_meta_key, '', true );
}

/**
 * Retrieve post meta fields, based on post ID.
 *
 * The post meta fields are retrieved from the cache where possible,
 * so the function is optimized to be called more than once.
 *
 * @since 1.2.0
 *
 * @param int $post_id Optional. Post ID. Default is ID of the global $post.
 * @return array Post meta for the given post.
 */
function get_post_custom( $post_id = 0 ) {
        $post_id = absint( $post_id );
        if ( ! $post_id )
                $post_id = get_the_ID();

        return get_post_meta( $post_id );
}

/**
 * Retrieve meta field names for a post.
 *
 * If there are no meta fields, then nothing (null) will be returned.
 *
 * @since 1.2.0
 *
 * @param int $post_id Optional. Post ID. Default is ID of the global $post.
 * @return array|void Array of the keys, if retrieved.
 */
function get_post_custom_keys( $post_id = 0 ) {
        $custom = get_post_custom( $post_id );

        if ( !is_array($custom) )
                return;

        if ( $keys = array_keys($custom) )
                return $keys;
}

/**
 * Retrieve values for a custom post field.
 *
 * The parameters must not be considered optional. All of the post meta fields
 * will be retrieved and only the meta field key values returned.
 *
 * @since 1.2.0
 *
 * @param string $key     Optional. Meta field key. Default empty.
 * @param int    $post_id Optional. Post ID. Default is ID of the global $post.
 * @return array|null Meta field values.
 */
function get_post_custom_values( $key = '', $post_id = 0 ) {
        if ( !$key )
                return null;

        $custom = get_post_custom($post_id);

        return isset($custom[$key]) ? $custom[$key] : null;
}

/**
 * Check if post is sticky.
 *
 * Sticky posts should remain at the top of The Loop. If the post ID is not
 * given, then The Loop ID for the current post will be used.
 *
 * @since 2.7.0
 *
 * @param int $post_id Optional. Post ID. Default is ID of the global $post.
 * @return bool Whether post is sticky.
 */
function is_sticky( $post_id = 0 ) {
        $post_id = absint( $post_id );

        if ( ! $post_id )
                $post_id = get_the_ID();

        $stickies = get_option( 'sticky_posts' );

        if ( ! is_array( $stickies ) )
                return false;

        if ( in_array( $post_id, $stickies ) )
                return true;

        return false;
}

/**
 * Sanitize every post field.
 *
 * If the context is 'raw', then the post object or array will get minimal
 * sanitization of the integer fields.
 *
 * @since 2.3.0
 *
 * @see sanitize_post_field()
 *
 * @param object|WP_Post|array $post    The Post Object or Array
 * @param string               $context Optional. How to sanitize post fields.
 *                                      Accepts 'raw', 'edit', 'db', or 'display'.
 *                                      Default 'display'.
 * @return object|WP_Post|array The now sanitized Post Object or Array (will be the
 *                              same type as $post).
 */
function sanitize_post( $post, $context = 'display' ) {
        if ( is_object($post) ) {
                // Check if post already filtered for this context.
                if ( isset($post->filter) && $context == $post->filter )
                        return $post;
                if ( !isset($post->ID) )
                        $post->ID = 0;
                foreach ( array_keys(get_object_vars($post)) as $field )
                        $post->$field = sanitize_post_field($field, $post->$field, $post->ID, $context);
                $post->filter = $context;
        } else {
                // Check if post already filtered for this context.
                if ( isset($post['filter']) && $context == $post['filter'] )
                        return $post;
                if ( !isset($post['ID']) )
                        $post['ID'] = 0;
                foreach ( array_keys($post) as $field )
                        $post[$field] = sanitize_post_field($field, $post[$field], $post['ID'], $context);
                $post['filter'] = $context;
        }
        return $post;
}

/**
 * Sanitize post field based on context.
 *
 * Possible context values are:  'raw', 'edit', 'db', 'display', 'attribute' and
 * 'js'. The 'display' context is used by default. 'attribute' and 'js' contexts
 * are treated like 'display' when calling filters.
 *
 * @since 2.3.0
 *
 * @param string $field   The Post Object field name.
 * @param mixed  $value   The Post Object value.
 * @param int    $post_id Post ID.
 * @param string $context How to sanitize post fields. Looks for 'raw', 'edit',
 *                        'db', 'display', 'attribute' and 'js'.
 * @return mixed Sanitized value.
 */
function sanitize_post_field($field, $value, $post_id, $context) {
        $int_fields = array('ID', 'post_parent', 'menu_order');
        if ( in_array($field, $int_fields) )
                $value = (int) $value;

        // Fields which contain arrays of integers.
        $array_int_fields = array( 'ancestors' );
        if ( in_array($field, $array_int_fields) ) {
                $value = array_map( 'absint', $value);
                return $value;
        }

        if ( 'raw' == $context )
                return $value;

        $prefixed = false;
        if ( false !== strpos($field, 'post_') ) {
                $prefixed = true;
                $field_no_prefix = str_replace('post_', '', $field);
        }

        if ( 'edit' == $context ) {
                $format_to_edit = array('post_content', 'post_excerpt', 'post_title', 'post_password');

                if ( $prefixed ) {

                        /**
                         * Filter the value of a specific post field to edit.
                         *
                         * The dynamic portion of the hook name, `$field`, refers to the post
                         * field name.
                         *
                         * @since 2.3.0
                         *
                         * @param mixed $value   Value of the post field.
                         * @param int   $post_id Post ID.
                         */
                        $value = apply_filters( "edit_{$field}", $value, $post_id );

                        /**
                         * Filter the value of a specific post field to edit.
                         *
                         * The dynamic portion of the hook name, `$field_no_prefix`, refers to
                         * the post field name.
                         *
                         * @since 2.3.0
                         *
                         * @param mixed $value   Value of the post field.
                         * @param int   $post_id Post ID.
                         */
                        $value = apply_filters( "{$field_no_prefix}_edit_pre", $value, $post_id );
                } else {
                        $value = apply_filters( "edit_post_{$field}", $value, $post_id );
                }

                if ( in_array($field, $format_to_edit) ) {
                        if ( 'post_content' == $field )
                                $value = format_to_edit($value, user_can_richedit());
                        else
                                $value = format_to_edit($value);
                } else {
                        $value = esc_attr($value);
                }
        } elseif ( 'db' == $context ) {
                if ( $prefixed ) {

                        /**
                         * Filter the value of a specific post field before saving.
                         *
                         * The dynamic portion of the hook name, `$field`, refers to the post
                         * field name.
                         *
                         * @since 2.3.0
                         *
                         * @param mixed $value Value of the post field.
                         */
                        $value = apply_filters( "pre_{$field}", $value );

                        /**
                         * Filter the value of a specific field before saving.
                         *
                         * The dynamic portion of the hook name, `$field_no_prefix`, refers
                         * to the post field name.
                         *
                         * @since 2.3.0
                         *
                         * @param mixed $value Value of the post field.
                         */
                        $value = apply_filters( "{$field_no_prefix}_save_pre", $value );
                } else {
                        $value = apply_filters( "pre_post_{$field}", $value );

                        /**
                         * Filter the value of a specific post field before saving.
                         *
                         * The dynamic portion of the hook name, `$field`, refers to the post
                         * field name.
                         *
                         * @since 2.3.0
                         *
                         * @param mixed $value Value of the post field.
                         */
                        $value = apply_filters( "{$field}_pre", $value );
                }
        } else {

                // Use display filters by default.
                if ( $prefixed ) {

                        /**
                         * Filter the value of a specific post field for display.
                         *
                         * The dynamic portion of the hook name, `$field`, refers to the post
                         * field name.
                         *
                         * @since 2.3.0
                         *
                         * @param mixed  $value   Value of the prefixed post field.
                         * @param int    $post_id Post ID.
                         * @param string $context Context for how to sanitize the field. Possible
                         *                        values include 'raw', 'edit', 'db', 'display',
                         *                        'attribute' and 'js'.
                         */
                        $value = apply_filters( $field, $value, $post_id, $context );
                } else {
                        $value = apply_filters( "post_{$field}", $value, $post_id, $context );
                }
        }

        if ( 'attribute' == $context )
                $value = esc_attr($value);
        elseif ( 'js' == $context )
                $value = esc_js($value);

        return $value;
}

/**
 * Make a post sticky.
 *
 * Sticky posts should be displayed at the top of the front page.
 *
 * @since 2.7.0
 *
 * @param int $post_id Post ID.
 */
function stick_post( $post_id ) {
        $stickies = get_option('sticky_posts');

        if ( !is_array($stickies) )
                $stickies = array($post_id);

        if ( ! in_array($post_id, $stickies) )
                $stickies[] = $post_id;

        update_option('sticky_posts', $stickies);
}

/**
 * Un-stick a post.
 *
 * Sticky posts should be displayed at the top of the front page.
 *
 * @since 2.7.0
 *
 * @param int $post_id Post ID.
 */
function unstick_post( $post_id ) {
        $stickies = get_option('sticky_posts');

        if ( !is_array($stickies) )
                return;

        if ( ! in_array($post_id, $stickies) )
                return;

        $offset = array_search($post_id, $stickies);
        if ( false === $offset )
                return;

        array_splice($stickies, $offset, 1);

        update_option('sticky_posts', $stickies);
}

/**
 * Return the cache key for wp_count_posts() based on the passed arguments.
 *
 * @since 3.9.0
 *
 * @param string $type Optional. Post type to retrieve count Default 'post'.
 * @param string $perm Optional. 'readable' or empty. Default empty.
 * @return string The cache key.
 */
function _count_posts_cache_key( $type = 'post', $perm = '' ) {
        $cache_key = 'posts-' . $type;
        if ( 'readable' == $perm && is_user_logged_in() ) {
                $post_type_object = get_post_type_object( $type );
                if ( $post_type_object && ! current_user_can( $post_type_object->cap->read_private_posts ) ) {
                        $cache_key .= '_' . $perm . '_' . get_current_user_id();
                }
        }
        return $cache_key;
}

/**
 * Count number of posts of a post type and if user has permissions to view.
 *
 * This function provides an efficient method of finding the amount of post's
 * type a blog has. Another method is to count the amount of items in
 * get_posts(), but that method has a lot of overhead with doing so. Therefore,
 * when developing for 2.5+, use this function instead.
 *
 * The $perm parameter checks for 'readable' value and if the user can read
 * private posts, it will display that for the user that is signed in.
 *
 * @since 2.5.0
 *
 * @global wpdb $wpdb
 *
 * @param string $type Optional. Post type to retrieve count. Default 'post'.
 * @param string $perm Optional. 'readable' or empty. Default empty.
 * @return object Number of posts for each status.
 */
function wp_count_posts( $type = 'post', $perm = '' ) {
        global $wpdb;

        if ( ! post_type_exists( $type ) )
                return new stdClass;

        $cache_key = _count_posts_cache_key( $type, $perm );

        $counts = wp_cache_get( $cache_key, 'counts' );
        if ( false !== $counts ) {
                /** This filter is documented in wp-includes/post.php */
                return apply_filters( 'wp_count_posts', $counts, $type, $perm );
        }

        $query = "SELECT post_status, COUNT( * ) AS num_posts FROM {$wpdb->posts} WHERE post_type = %s";
        if ( 'readable' == $perm && is_user_logged_in() ) {
                $post_type_object = get_post_type_object($type);
                if ( ! current_user_can( $post_type_object->cap->read_private_posts ) ) {
                        $query .= $wpdb->prepare( " AND (post_status != 'private' OR ( post_author = %d AND post_status = 'private' ))",
                                get_current_user_id()
                        );
                }
        }
        $query .= ' GROUP BY post_status';

        $results = (array) $wpdb->get_results( $wpdb->prepare( $query, $type ), ARRAY_A );
        $counts = array_fill_keys( get_post_stati(), 0 );

        foreach ( $results as $row ) {
                $counts[ $row['post_status'] ] = $row['num_posts'];
        }

        $counts = (object) $counts;
        wp_cache_set( $cache_key, $counts, 'counts' );

        /**
         * Modify returned post counts by status for the current post type.
         *
         * @since 3.7.0
         *
         * @param object $counts An object containing the current post_type's post
         *                       counts by status.
         * @param string $type   Post type.
         * @param string $perm   The permission to determine if the posts are 'readable'
         *                       by the current user.
         */
        return apply_filters( 'wp_count_posts', $counts, $type, $perm );
}

/**
 * Count number of attachments for the mime type(s).
 *
 * If you set the optional mime_type parameter, then an array will still be
 * returned, but will only have the item you are looking for. It does not give
 * you the number of attachments that are children of a post. You can get that
 * by counting the number of children that post has.
 *
 * @since 2.5.0
 *
 * @global wpdb $wpdb
 *
 * @param string|array $mime_type Optional. Array or comma-separated list of
 *                                MIME patterns. Default empty.
 * @return object An object containing the attachment counts by mime type.
 */
function wp_count_attachments( $mime_type = '' ) {
        global $wpdb;

        $and = wp_post_mime_type_where( $mime_type );
        $count = $wpdb->get_results( "SELECT post_mime_type, COUNT( * ) AS num_posts FROM $wpdb->posts WHERE post_type = 'attachment' AND post_status != 'trash' $and GROUP BY post_mime_type", ARRAY_A );

        $counts = array();
        foreach( (array) $count as $row ) {
                $counts[ $row['post_mime_type'] ] = $row['num_posts'];
        }
        $counts['trash'] = $wpdb->get_var( "SELECT COUNT( * ) FROM $wpdb->posts WHERE post_type = 'attachment' AND post_status = 'trash' $and");

        /**
         * Modify returned attachment counts by mime type.
         *
         * @since 3.7.0
         *
         * @param object $counts    An object containing the attachment counts by
         *                          mime type.
         * @param string $mime_type The mime type pattern used to filter the attachments
         *                          counted.
         */
        return apply_filters( 'wp_count_attachments', (object) $counts, $mime_type );
}

/**
 * Get default post mime types.
 *
 * @since 2.9.0
 *
 * @return array List of post mime types.
 */
function get_post_mime_types() {
        $post_mime_types = array(       //      array( adj, noun )
                'image' => array(__('Images'), __('Manage Images'), _n_noop('Image <span class="count">(%s)</span>', 'Images <span class="count">(%s)</span>')),
                'audio' => array(__('Audio'), __('Manage Audio'), _n_noop('Audio <span class="count">(%s)</span>', 'Audio <span class="count">(%s)</span>')),
                'video' => array(__('Video'), __('Manage Video'), _n_noop('Video <span class="count">(%s)</span>', 'Video <span class="count">(%s)</span>')),
        );

        /**
         * Filter the default list of post mime types.
         *
         * @since 2.5.0
         *
         * @param array $post_mime_types Default list of post mime types.
         */
        return apply_filters( 'post_mime_types', $post_mime_types );
}

/**
 * Check a MIME-Type against a list.
 *
 * If the wildcard_mime_types parameter is a string, it must be comma separated
 * list. If the real_mime_types is a string, it is also comma separated to
 * create the list.
 *
 * @since 2.5.0
 *
 * @param string|array $wildcard_mime_types Mime types, e.g. audio/mpeg or image (same as image/*)
 *                                          or flash (same as *flash*).
 * @param string|array $real_mime_types     Real post mime type values.
 * @return array array(wildcard=>array(real types)).
 */
function wp_match_mime_types( $wildcard_mime_types, $real_mime_types ) {
        $matches = array();
        if ( is_string( $wildcard_mime_types ) ) {
                $wildcard_mime_types = array_map( 'trim', explode( ',', $wildcard_mime_types ) );
        }
        if ( is_string( $real_mime_types ) ) {
                $real_mime_types = array_map( 'trim', explode( ',', $real_mime_types ) );
        }

        $patternses = array();
        $wild = '[-._a-z0-9]*';

        foreach ( (array) $wildcard_mime_types as $type ) {
                $mimes = array_map( 'trim', explode( ',', $type ) );
                foreach ( $mimes as $mime ) {
                        $regex = str_replace( '__wildcard__', $wild, preg_quote( str_replace( '*', '__wildcard__', $mime ) ) );
                        $patternses[][$type] = "^$regex$";
                        if ( false === strpos( $mime, '/' ) ) {
                                $patternses[][$type] = "^$regex/";
                                $patternses[][$type] = $regex;
                        }
                }
        }
        asort( $patternses );

        foreach ( $patternses as $patterns ) {
                foreach ( $patterns as $type => $pattern ) {
                        foreach ( (array) $real_mime_types as $real ) {
                                if ( preg_match( "#$pattern#", $real ) && ( empty( $matches[$type] ) || false === array_search( $real, $matches[$type] ) ) ) {
                                        $matches[$type][] = $real;
                                }
                        }
                }
        }
        return $matches;
}

/**
 * Convert MIME types into SQL.
 *
 * @since 2.5.0
 *
 * @param string|array $post_mime_types List of mime types or comma separated string
 *                                      of mime types.
 * @param string       $table_alias     Optional. Specify a table alias, if needed.
 *                                      Default empty.
 * @return string The SQL AND clause for mime searching.
 */
function wp_post_mime_type_where( $post_mime_types, $table_alias = '' ) {
        $where = '';
        $wildcards = array('', '%', '%/%');
        if ( is_string($post_mime_types) )
                $post_mime_types = array_map('trim', explode(',', $post_mime_types));

        $wheres = array();

        foreach ( (array) $post_mime_types as $mime_type ) {
                $mime_type = preg_replace('/\s/', '', $mime_type);
                $slashpos = strpos($mime_type, '/');
                if ( false !== $slashpos ) {
                        $mime_group = preg_replace('/[^-*.a-zA-Z0-9]/', '', substr($mime_type, 0, $slashpos));
                        $mime_subgroup = preg_replace('/[^-*.+a-zA-Z0-9]/', '', substr($mime_type, $slashpos + 1));
                        if ( empty($mime_subgroup) )
                                $mime_subgroup = '*';
                        else
                                $mime_subgroup = str_replace('/', '', $mime_subgroup);
                        $mime_pattern = "$mime_group/$mime_subgroup";
                } else {
                        $mime_pattern = preg_replace('/[^-*.a-zA-Z0-9]/', '', $mime_type);
                        if ( false === strpos($mime_pattern, '*') )
                                $mime_pattern .= '/*';
                }

                $mime_pattern = preg_replace('/\*+/', '%', $mime_pattern);

                if ( in_array( $mime_type, $wildcards ) )
                        return '';

                if ( false !== strpos($mime_pattern, '%') )
                        $wheres[] = empty($table_alias) ? "post_mime_type LIKE '$mime_pattern'" : "$table_alias.post_mime_type LIKE '$mime_pattern'";
                else
                        $wheres[] = empty($table_alias) ? "post_mime_type = '$mime_pattern'" : "$table_alias.post_mime_type = '$mime_pattern'";
        }
        if ( !empty($wheres) )
                $where = ' AND (' . join(' OR ', $wheres) . ') ';
        return $where;
}

/**
 * Trash or delete a post or page.
 *
 * When the post and page is permanently deleted, everything that is tied to
 * it is deleted also. This includes comments, post meta fields, and terms
 * associated with the post.
 *
 * The post or page is moved to trash instead of permanently deleted unless
 * trash is disabled, item is already in the trash, or $force_delete is true.
 *
 * @since 1.0.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 * @see wp_delete_attachment()
 * @see wp_trash_post()
 *
 * @param int  $postid       Optional. Post ID. Default 0.
 * @param bool $force_delete Optional. Whether to bypass trash and force deletion.
 *                           Default false.
 * @return array|false|WP_Post False on failure.
 */
function wp_delete_post( $postid = 0, $force_delete = false ) {
        global $wpdb;

        if ( !$post = $wpdb->get_row($wpdb->prepare("SELECT * FROM $wpdb->posts WHERE ID = %d", $postid)) )
                return $post;

        if ( !$force_delete && ( $post->post_type == 'post' || $post->post_type == 'page') && get_post_status( $postid ) != 'trash' && EMPTY_TRASH_DAYS )
                return wp_trash_post( $postid );

        if ( $post->post_type == 'attachment' )
                return wp_delete_attachment( $postid, $force_delete );

        /**
         * Fires before a post is deleted, at the start of wp_delete_post().
         *
         * @since 3.2.0
         *
         * @see wp_delete_post()
         *
         * @param int $postid Post ID.
         */
        do_action( 'before_delete_post', $postid );

        delete_post_meta($postid,'_wp_trash_meta_status');
        delete_post_meta($postid,'_wp_trash_meta_time');

        wp_delete_object_term_relationships($postid, get_object_taxonomies($post->post_type));

        $parent_data = array( 'post_parent' => $post->post_parent );
        $parent_where = array( 'post_parent' => $postid );

        if ( is_post_type_hierarchical( $post->post_type ) ) {
                // Point children of this page to its parent, also clean the cache of affected children.
                $children_query = $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE post_parent = %d AND post_type = %s", $postid, $post->post_type );
                $children = $wpdb->get_results( $children_query );

                $wpdb->update( $wpdb->posts, $parent_data, $parent_where + array( 'post_type' => $post->post_type ) );
        }

        // Do raw query. wp_get_post_revisions() is filtered.
        $revision_ids = $wpdb->get_col( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE post_parent = %d AND post_type = 'revision'", $postid ) );
        // Use wp_delete_post (via wp_delete_post_revision) again. Ensures any meta/misplaced data gets cleaned up.
        foreach ( $revision_ids as $revision_id )
                wp_delete_post_revision( $revision_id );

        // Point all attachments to this post up one level.
        $wpdb->update( $wpdb->posts, $parent_data, $parent_where + array( 'post_type' => 'attachment' ) );

        $comment_ids = $wpdb->get_col( $wpdb->prepare( "SELECT comment_ID FROM $wpdb->comments WHERE comment_post_ID = %d", $postid ));
        foreach ( $comment_ids as $comment_id )
                wp_delete_comment( $comment_id, true );

        $post_meta_ids = $wpdb->get_col( $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE post_id = %d ", $postid ));
        foreach ( $post_meta_ids as $mid )
                delete_metadata_by_mid( 'post', $mid );

        /**
         * Fires immediately before a post is deleted from the database.
         *
         * @since 1.2.0
         *
         * @param int $postid Post ID.
         */
        do_action( 'delete_post', $postid );
        $result = $wpdb->delete( $wpdb->posts, array( 'ID' => $postid ) );
        if ( ! $result ) {
                return false;
        }

        /**
         * Fires immediately after a post is deleted from the database.
         *
         * @since 2.2.0
         *
         * @param int $postid Post ID.
         */
        do_action( 'deleted_post', $postid );

        clean_post_cache( $post );

        if ( is_post_type_hierarchical( $post->post_type ) && $children ) {
                foreach ( $children as $child )
                        clean_post_cache( $child );
        }

        wp_clear_scheduled_hook('publish_future_post', array( $postid ) );

        /**
         * Fires after a post is deleted, at the conclusion of wp_delete_post().
         *
         * @since 3.2.0
         *
         * @see wp_delete_post()
         *
         * @param int $postid Post ID.
         */
        do_action( 'after_delete_post', $postid );

        return $post;
}

/**
 * Reset the page_on_front, show_on_front, and page_for_post settings when
 * a linked page is deleted or trashed.
 *
 * Also ensures the post is no longer sticky.
 *
 * @since 3.7.0
 * @access private
 *
 * @param int $post_id Post ID.
 */
function _reset_front_page_settings_for_post( $post_id ) {
        $post = get_post( $post_id );
        if ( 'page' == $post->post_type ) {
                /*
                 * If the page is defined in option page_on_front or post_for_posts,
                 * adjust the corresponding options.
                 */
                if ( get_option( 'page_on_front' ) == $post->ID ) {
                        update_option( 'show_on_front', 'posts' );
                        update_option( 'page_on_front', 0 );
                }
                if ( get_option( 'page_for_posts' ) == $post->ID ) {
                        delete_option( 'page_for_posts', 0 );
                }
        }
        unstick_post( $post->ID );
}

/**
 * Move a post or page to the Trash
 *
 * If trash is disabled, the post or page is permanently deleted.
 *
 * @since 2.9.0
 *
 * @see wp_delete_post()
 *
 * @param int $post_id Optional. Post ID. Default is ID of the global $post
 *                     if EMPTY_TRASH_DAYS equals true.
 * @return false|array|WP_Post|null Post data array, otherwise false.
 */
function wp_trash_post( $post_id = 0 ) {
        if ( !EMPTY_TRASH_DAYS )
                return wp_delete_post($post_id, true);

        if ( !$post = get_post($post_id, ARRAY_A) )
                return $post;

        if ( $post['post_status'] == 'trash' )
                return false;

        /**
         * Fires before a post is sent to the trash.
         *
         * @since 3.3.0
         *
         * @param int $post_id Post ID.
         */
        do_action( 'wp_trash_post', $post_id );

        add_post_meta($post_id,'_wp_trash_meta_status', $post['post_status']);
        add_post_meta($post_id,'_wp_trash_meta_time', time());

        $post['post_status'] = 'trash';
        wp_insert_post($post);

        wp_trash_post_comments($post_id);

        /**
         * Fires after a post is sent to the trash.
         *
         * @since 2.9.0
         *
         * @param int $post_id Post ID.
         */
        do_action( 'trashed_post', $post_id );

        return $post;
}

/**
 * Restore a post or page from the Trash.
 *
 * @since 2.9.0
 *
 * @param int $post_id Optional. Post ID. Default is ID of the global $post.
 * @return WP_Post|false WP_Post object. False on failure.
 */
function wp_untrash_post( $post_id = 0 ) {
        if ( !$post = get_post($post_id, ARRAY_A) )
                return $post;

        if ( $post['post_status'] != 'trash' )
                return false;

        /**
         * Fires before a post is restored from the trash.
         *
         * @since 2.9.0
         *
         * @param int $post_id Post ID.
         */
        do_action( 'untrash_post', $post_id );

        $post_status = get_post_meta($post_id, '_wp_trash_meta_status', true);

        $post['post_status'] = $post_status;

        delete_post_meta($post_id, '_wp_trash_meta_status');
        delete_post_meta($post_id, '_wp_trash_meta_time');

        wp_insert_post($post);

        wp_untrash_post_comments($post_id);

        /**
         * Fires after a post is restored from the trash.
         *
         * @since 2.9.0
         *
         * @param int $post_id Post ID.
         */
        do_action( 'untrashed_post', $post_id );

        return $post;
}

/**
 * Moves comments for a post to the trash.
 *
 * @since 2.9.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int|WP_Post|null $post Optional. Post ID or post object. Defaults to global $post.
 * @return mixed|void False on failure.
 */
function wp_trash_post_comments( $post = null ) {
        global $wpdb;

        $post = get_post($post);
        if ( empty($post) )
                return;

        $post_id = $post->ID;

        /**
         * Fires before comments are sent to the trash.
         *
         * @since 2.9.0
         *
         * @param int $post_id Post ID.
         */
        do_action( 'trash_post_comments', $post_id );

        $comments = $wpdb->get_results( $wpdb->prepare("SELECT comment_ID, comment_approved FROM $wpdb->comments WHERE comment_post_ID = %d", $post_id) );
        if ( empty($comments) )
                return;

        // Cache current status for each comment.
        $statuses = array();
        foreach ( $comments as $comment )
                $statuses[$comment->comment_ID] = $comment->comment_approved;
        add_post_meta($post_id, '_wp_trash_meta_comments_status', $statuses);

        // Set status for all comments to post-trashed.
        $result = $wpdb->update($wpdb->comments, array('comment_approved' => 'post-trashed'), array('comment_post_ID' => $post_id));

        clean_comment_cache( array_keys($statuses) );

        /**
         * Fires after comments are sent to the trash.
         *
         * @since 2.9.0
         *
         * @param int   $post_id  Post ID.
         * @param array $statuses Array of comment statuses.
         */
        do_action( 'trashed_post_comments', $post_id, $statuses );

        return $result;
}

/**
 * Restore comments for a post from the trash.
 *
 * @since 2.9.0
 *
 * @global wpdb $wpdb
 *
 * @param int|WP_Post|null $post Optional. Post ID or post object. Defaults to global $post.
 * @return true|void
 */
function wp_untrash_post_comments( $post = null ) {
        global $wpdb;

        $post = get_post($post);
        if ( empty($post) )
                return;

        $post_id = $post->ID;

        $statuses = get_post_meta($post_id, '_wp_trash_meta_comments_status', true);

        if ( empty($statuses) )
                return true;

        /**
         * Fires before comments are restored for a post from the trash.
         *
         * @since 2.9.0
         *
         * @param int $post_id Post ID.
         */
        do_action( 'untrash_post_comments', $post_id );

        // Restore each comment to its original status.
        $group_by_status = array();
        foreach ( $statuses as $comment_id => $comment_status )
                $group_by_status[$comment_status][] = $comment_id;

        foreach ( $group_by_status as $status => $comments ) {
                // Sanity check. This shouldn't happen.
                if ( 'post-trashed' == $status ) {
                        $status = '0';
                }
                $comments_in = implode( ', ', array_map( 'intval', $comments ) );
                $wpdb->query( $wpdb->prepare( "UPDATE $wpdb->comments SET comment_approved = %s WHERE comment_ID IN ($comments_in)", $status ) );
        }

        clean_comment_cache( array_keys($statuses) );

        delete_post_meta($post_id, '_wp_trash_meta_comments_status');

        /**
         * Fires after comments are restored for a post from the trash.
         *
         * @since 2.9.0
         *
         * @param int $post_id Post ID.
         */
        do_action( 'untrashed_post_comments', $post_id );
}

/**
 * Retrieve the list of categories for a post.
 *
 * Compatibility layer for themes and plugins. Also an easy layer of abstraction
 * away from the complexity of the taxonomy layer.
 *
 * @since 2.1.0
 *
 * @see wp_get_object_terms()
 *
 * @param int   $post_id Optional. The Post ID. Does not default to the ID of the
 *                       global $post. Default 0.
 * @param array $args    Optional. Category arguments. Default empty.
 * @return array List of categories.
 */
function wp_get_post_categories( $post_id = 0, $args = array() ) {
        $post_id = (int) $post_id;

        $defaults = array('fields' => 'ids');
        $args = wp_parse_args( $args, $defaults );

        $cats = wp_get_object_terms($post_id, 'category', $args);
        return $cats;
}

/**
 * Retrieve the tags for a post.
 *
 * There is only one default for this function, called 'fields' and by default
 * is set to 'all'. There are other defaults that can be overridden in
 * {@link wp_get_object_terms()}.
 *
 * @since 2.3.0
 *
 * @param int   $post_id Optional. The Post ID. Does not default to the ID of the
 *                       global $post. Defualt 0.
 * @param array $args Optional. Overwrite the defaults
 * @return array List of post tags.
 */
function wp_get_post_tags( $post_id = 0, $args = array() ) {
        return wp_get_post_terms( $post_id, 'post_tag', $args);
}

/**
 * Retrieve the terms for a post.
 *
 * There is only one default for this function, called 'fields' and by default
 * is set to 'all'. There are other defaults that can be overridden in
 * {@link wp_get_object_terms()}.
 *
 * @since 2.8.0
 *
 * @param int    $post_id  Optional. The Post ID. Does not default to the ID of the
 *                         global $post. Default 0.
 * @param string $taxonomy Optional. The taxonomy for which to retrieve terms. Default 'post_tag'.
 * @param array  $args     Optional. {@link wp_get_object_terms()} arguments. Default empty array.
 * @return array|WP_Error  List of post terms or empty array if no terms were found. WP_Error object
 *                         if `$taxonomy` doesn't exist.
 */
function wp_get_post_terms( $post_id = 0, $taxonomy = 'post_tag', $args = array() ) {
        $post_id = (int) $post_id;

        $defaults = array('fields' => 'all');
        $args = wp_parse_args( $args, $defaults );

        $tags = wp_get_object_terms($post_id, $taxonomy, $args);

        return $tags;
}

/**
 * Retrieve a number of recent posts.
 *
 * @since 1.0.0
 *
 * @see get_posts()
 *
 * @param array  $args       Optional. Arguments to retrieve posts. Default empty array.
 * @param string $output     Optional. Type of output. Accepts ARRAY_A or ''. Default ARRAY_A.
 * @return array|false Associative array if $output equals ARRAY_A, array or false if no results.
 */
function wp_get_recent_posts( $args = array(), $output = ARRAY_A ) {

        if ( is_numeric( $args ) ) {
                _deprecated_argument( __FUNCTION__, '3.1', __( 'Passing an integer number of posts is deprecated. Pass an array of arguments instead.' ) );
                $args = array( 'numberposts' => absint( $args ) );
        }

        // Set default arguments.
        $defaults = array(
                'numberposts' => 10, 'offset' => 0,
                'category' => 0, 'orderby' => 'post_date',
                'order' => 'DESC', 'include' => '',
                'exclude' => '', 'meta_key' => '',
                'meta_value' =>'', 'post_type' => 'post', 'post_status' => 'draft, publish, future, pending, private',
                'suppress_filters' => true
        );

        $r = wp_parse_args( $args, $defaults );

        $results = get_posts( $r );

        // Backward compatibility. Prior to 3.1 expected posts to be returned in array.
        if ( ARRAY_A == $output ){
                foreach( $results as $key => $result ) {
                        $results[$key] = get_object_vars( $result );
                }
                return $results ? $results : array();
        }

        return $results ? $results : false;

}

/**
 * Insert or update a post.
 *
 * If the $postarr parameter has 'ID' set to a value, then post will be updated.
 *
 * You can set the post date manually, by setting the values for 'post_date'
 * and 'post_date_gmt' keys. You can close the comments or open the comments by
 * setting the value for 'comment_status' key.
 *
 * @since 1.0.0
 * @since 4.2.0 Support was added for encoding emoji in the post title, content, and excerpt.
 *
 * @see sanitize_post()
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param array $postarr {
 *     An array of elements that make up a post to update or insert.
 *
 *     @type int    $ID                    The post ID. If equal to something other than 0,
 *                                         the post with that ID will be updated. Default 0.
 *     @type int    $post_author           The ID of the user who added the post. Default is
 *                                         the current user ID.
 *     @type string $post_date             The date of the post. Default is the current time.
 *     @type string $post_date_gmt         The date of the post in the GMT timezone. Default is
 *                                         the value of `$post_date`.
 *     @type mixed  $post_content          The post content. Default empty.
 *     @type string $post_content_filtered The filtered post content. Default empty.
 *     @type string $post_title            The post title. Default empty.
 *     @type string $post_excerpt          The post excerpt. Default empty.
 *     @type string $post_status           The post status. Default 'draft'.
 *     @type string $post_type             The post type. Default 'post'.
 *     @type string $comment_status        Whether the post can accept comments. Accepts 'open' or 'closed'.
 *                                         Default is the value of 'default_comment_status' option.
 *     @type string $ping_status           Whether the post can accept pings. Accepts 'open' or 'closed'.
 *                                         Default is the value of 'default_ping_status' option.
 *     @type string $post_password         The password to access the post. Default empty.
 *     @type string $post_name             The post name. Default is the sanitized post title.
 *     @type string $to_ping               Space or carriage return-separated list of URLs to ping.
 *                                         Default empty.
 *     @type string $pinged                Space or carriage return-separated list of URLs that have
 *                                         been pinged. Default empty.
 *     @type string $post_modified         The date when the post was last modified. Default is
 *                                         the current time.
 *     @type string $post_modified_gmt     The date when the post was last modified in the GMT
 *                                         timezone. Default is the current time.
 *     @type int    $post_parent           Set this for the post it belongs to, if any. Default 0.
 *     @type int    $menu_order            The order the post should be displayed in. Default 0.
 *     @type string $post_mime_type        The mime type of the post. Default empty.
 *     @type string $guid                  Global Unique ID for referencing the post. Default empty.
 * }
 * @param bool  $wp_error Optional. Whether to allow return of WP_Error on failure. Default false.
 * @return int|WP_Error The post ID on success. The value 0 or WP_Error on failure.
 */
function wp_insert_post( $postarr, $wp_error = false ) {
        global $wpdb;

        $user_id = get_current_user_id();

        $defaults = array(
                'post_author' => $user_id,
                'post_content' => '',
                'post_content_filtered' => '',
                'post_title' => '',
                'post_excerpt' => '',
                'post_status' => 'draft',
                'post_type' => 'post',
                'comment_status' => '',
                'ping_status' => '',
                'post_password' => '',
                'to_ping' =>  '',
                'pinged' => '',
                'post_parent' => 0,
                'menu_order' => 0,
                'guid' => '',
                'import_id' => 0,
                'context' => '',
        );

        $postarr = wp_parse_args($postarr, $defaults);

        unset( $postarr[ 'filter' ] );

        $postarr = sanitize_post($postarr, 'db');

        // Are we updating or creating?
        $post_ID = 0;
        $update = false;
        $guid = $postarr['guid'];

        if ( ! empty( $postarr['ID'] ) ) {
                $update = true;

                // Get the post ID and GUID.
                $post_ID = $postarr['ID'];
                $post_before = get_post( $post_ID );
                if ( is_null( $post_before ) ) {
                        if ( $wp_error ) {
                                return new WP_Error( 'invalid_post', __( 'Invalid post ID.' ) );
                        }
                        return 0;
                }

                $guid = get_post_field( 'guid', $post_ID );
                $previous_status = get_post_field('post_status', $post_ID );
        } else {
                $previous_status = 'new';
        }

        $post_type = empty( $postarr['post_type'] ) ? 'post' : $postarr['post_type'];

        $post_title = $postarr['post_title'];
        $post_content = $postarr['post_content'];
        $post_excerpt = $postarr['post_excerpt'];
        if ( isset( $postarr['post_name'] ) ) {
                $post_name = $postarr['post_name'];
        }

        $maybe_empty = 'attachment' !== $post_type
                && ! $post_content && ! $post_title && ! $post_excerpt
                && post_type_supports( $post_type, 'editor' )
                && post_type_supports( $post_type, 'title' )
                && post_type_supports( $post_type, 'excerpt' );

        /**
         * Filter whether the post should be considered "empty".
         *
         * The post is considered "empty" if both:
         * 1. The post type supports the title, editor, and excerpt fields
         * 2. The title, editor, and excerpt fields are all empty
         *
         * Returning a truthy value to the filter will effectively short-circuit
         * the new post being inserted, returning 0. If $wp_error is true, a WP_Error
         * will be returned instead.
         *
         * @since 3.3.0
         *
         * @param bool  $maybe_empty Whether the post should be considered "empty".
         * @param array $postarr     Array of post data.
         */
        if ( apply_filters( 'wp_insert_post_empty_content', $maybe_empty, $postarr ) ) {
                if ( $wp_error ) {
                        return new WP_Error( 'empty_content', __( 'Content, title, and excerpt are empty.' ) );
                } else {
                        return 0;
                }
        }

        $post_status = empty( $postarr['post_status'] ) ? 'draft' : $postarr['post_status'];
        if ( 'attachment' === $post_type && ! in_array( $post_status, array( 'inherit', 'private', 'trash' ) ) ) {
                $post_status = 'inherit';
        }

        if ( ! empty( $postarr['post_category'] ) ) {
                // Filter out empty terms.
                $post_category = array_filter( $postarr['post_category'] );
        }

        // Make sure we set a valid category.
        if ( empty( $post_category ) || 0 == count( $post_category ) || ! is_array( $post_category ) ) {
                // 'post' requires at least one category.
                if ( 'post' == $post_type && 'auto-draft' != $post_status ) {
                        $post_category = array( get_option('default_category') );
                } else {
                        $post_category = array();
                }
        }

        // Don't allow contributors to set the post slug for pending review posts.
        if ( 'pending' == $post_status && !current_user_can( 'publish_posts' ) ) {
                $post_name = '';
        }

        /*
         * Create a valid post name. Drafts and pending posts are allowed to have
         * an empty post name.
         */
        if ( empty($post_name) ) {
                if ( !in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) ) {
                        $post_name = sanitize_title($post_title);
                } else {
                        $post_name = '';
                }
        } else {
                // On updates, we need to check to see if it's using the old, fixed sanitization context.
                $check_name = sanitize_title( $post_name, '', 'old-save' );
                if ( $update && strtolower( urlencode( $post_name ) ) == $check_name && get_post_field( 'post_name', $post_ID ) == $check_name ) {
                        $post_name = $check_name;
                } else { // new post, or slug has changed.
                        $post_name = sanitize_title($post_name);
                }
        }

        /*
         * If the post date is empty (due to having been new or a draft) and status
         * is not 'draft' or 'pending', set date to now.
         */
        if ( empty( $postarr['post_date'] ) || '0000-00-00 00:00:00' == $postarr['post_date'] ) {
                $post_date = current_time( 'mysql' );
        } else {
                $post_date = $postarr['post_date'];
        }

        // Validate the date.
        $mm = substr( $post_date, 5, 2 );
        $jj = substr( $post_date, 8, 2 );
        $aa = substr( $post_date, 0, 4 );
        $valid_date = wp_checkdate( $mm, $jj, $aa, $post_date );
        if ( ! $valid_date ) {
                if ( $wp_error ) {
                        return new WP_Error( 'invalid_date', __( 'Whoops, the provided date is invalid.' ) );
                } else {
                        return 0;
                }
        }

        if ( empty( $postarr['post_date_gmt'] ) || '0000-00-00 00:00:00' == $postarr['post_date_gmt'] ) {
                if ( ! in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) ) {
                        $post_date_gmt = get_gmt_from_date( $post_date );
                } else {
                        $post_date_gmt = '0000-00-00 00:00:00';
                }
        } else {
                $post_date_gmt = $postarr['post_date_gmt'];
        }

        if ( $update || '0000-00-00 00:00:00' == $post_date ) {
                $post_modified     = current_time( 'mysql' );
                $post_modified_gmt = current_time( 'mysql', 1 );
        } else {
                $post_modified     = $post_date;
                $post_modified_gmt = $post_date_gmt;
        }

        if ( 'attachment' !== $post_type ) {
                if ( 'publish' == $post_status ) {
                        $now = gmdate('Y-m-d H:i:59');
                        if ( mysql2date('U', $post_date_gmt, false) > mysql2date('U', $now, false) ) {
                                $post_status = 'future';
                        }
                } elseif ( 'future' == $post_status ) {
                        $now = gmdate('Y-m-d H:i:59');
                        if ( mysql2date('U', $post_date_gmt, false) <= mysql2date('U', $now, false) ) {
                                $post_status = 'publish';
                        }
                }
        }

        // Comment status.
        if ( empty( $postarr['comment_status'] ) ) {
                if ( $update ) {
                        $comment_status = 'closed';
                } else {
                        $comment_status = get_default_comment_status( $post_type );
                }
        } else {
                $comment_status = $postarr['comment_status'];
        }

        // These variables are needed by compact() later.
        $post_content_filtered = $postarr['post_content_filtered'];
        $post_author = empty( $postarr['post_author'] ) ? $user_id : $postarr['post_author'];
        $ping_status = empty( $postarr['ping_status'] ) ? get_default_comment_status( $post_type, 'pingback' ) : $postarr['ping_status'];
        $to_ping = isset( $postarr['to_ping'] ) ? sanitize_trackback_urls( $postarr['to_ping'] ) : '';
        $pinged = isset( $postarr['pinged'] ) ? $postarr['pinged'] : '';
        $import_id = isset( $postarr['import_id'] ) ? $postarr['import_id'] : 0;

        /*
         * The 'wp_insert_post_parent' filter expects all variables to be present.
         * Previously, these variables would have already been extracted
         */
        if ( isset( $postarr['menu_order'] ) ) {
                $menu_order = (int) $postarr['menu_order'];
        } else {
                $menu_order = 0;
        }

        $post_password = isset( $postarr['post_password'] ) ? $postarr['post_password'] : '';
        if ( 'private' == $post_status ) {
                $post_password = '';
        }

        if ( isset( $postarr['post_parent'] ) ) {
                $post_parent = (int) $postarr['post_parent'];
        } else {
                $post_parent = 0;
        }

        /**
         * Filter the post parent -- used to check for and prevent hierarchy loops.
         *
         * @since 3.1.0
         *
         * @param int   $post_parent Post parent ID.
         * @param int   $post_ID     Post ID.
         * @param array $new_postarr Array of parsed post data.
         * @param array $postarr     Array of sanitized, but otherwise unmodified post data.
         */
        $post_parent = apply_filters( 'wp_insert_post_parent', $post_parent, $post_ID, compact( array_keys( $postarr ) ), $postarr );

        $post_name = wp_unique_post_slug( $post_name, $post_ID, $post_status, $post_type, $post_parent );

        // Don't unslash.
        $post_mime_type = isset( $postarr['post_mime_type'] ) ? $postarr['post_mime_type'] : '';

        // Expected_slashed (everything!).
        $data = compact( 'post_author', 'post_date', 'post_date_gmt', 'post_content', 'post_content_filtered', 'post_title', 'post_excerpt', 'post_status', 'post_type', 'comment_status', 'ping_status', 'post_password', 'post_name', 'to_ping', 'pinged', 'post_modified', 'post_modified_gmt', 'post_parent', 'menu_order', 'post_mime_type', 'guid' );

        $emoji_fields = array( 'post_title', 'post_content', 'post_excerpt' );

        foreach( $emoji_fields as $emoji_field ) {
                if ( isset( $data[ $emoji_field ] ) ) {
                        $charset = $wpdb->get_col_charset( $wpdb->posts, $emoji_field );
                        if ( 'utf8' === $charset ) {
                                $data[ $emoji_field ] = wp_encode_emoji( $data[ $emoji_field ] );
                        }
                }
        }

        if ( 'attachment' === $post_type ) {
                /**
                 * Filter attachment post data before it is updated in or added to the database.
                 *
                 * @since 3.9.0
                 *
                 * @param array $data    An array of sanitized attachment post data.
                 * @param array $postarr An array of unsanitized attachment post data.
                 */
                $data = apply_filters( 'wp_insert_attachment_data', $data, $postarr );
        } else {
                /**
                 * Filter slashed post data just before it is inserted into the database.
                 *
                 * @since 2.7.0
                 *
                 * @param array $data    An array of slashed post data.
                 * @param array $postarr An array of sanitized, but otherwise unmodified post data.
                 */
                $data = apply_filters( 'wp_insert_post_data', $data, $postarr );
        }
        $data = wp_unslash( $data );
        $where = array( 'ID' => $post_ID );

        if ( $update ) {
                /**
                 * Fires immediately before an existing post is updated in the database.
                 *
                 * @since 2.5.0
                 *
                 * @param int   $post_ID Post ID.
                 * @param array $data    Array of unslashed post data.
                 */
                do_action( 'pre_post_update', $post_ID, $data );
                if ( false === $wpdb->update( $wpdb->posts, $data, $where ) ) {
                        if ( $wp_error ) {
                                return new WP_Error('db_update_error', __('Could not update post in the database'), $wpdb->last_error);
                        } else {
                                return 0;
                        }
                }
        } else {
                // If there is a suggested ID, use it if not already present.
                if ( ! empty( $import_id ) ) {
                        $import_id = (int) $import_id;
                        if ( ! $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->posts WHERE ID = %d", $import_id) ) ) {
                                $data['ID'] = $import_id;
                        }
                }
                if ( false === $wpdb->insert( $wpdb->posts, $data ) ) {
                        if ( $wp_error ) {
                                return new WP_Error('db_insert_error', __('Could not insert post into the database'), $wpdb->last_error);
                        } else {
                                return 0;
                        }
                }
                $post_ID = (int) $wpdb->insert_id;

                // Use the newly generated $post_ID.
                $where = array( 'ID' => $post_ID );
        }

        if ( empty( $data['post_name'] ) && ! in_array( $data['post_status'], array( 'draft', 'pending', 'auto-draft' ) ) ) {
                $data['post_name'] = wp_unique_post_slug( sanitize_title( $data['post_title'], $post_ID ), $post_ID, $data['post_status'], $post_type, $post_parent );
                $wpdb->update( $wpdb->posts, array( 'post_name' => $data['post_name'] ), $where );
                clean_post_cache( $post_ID );
        }

        if ( is_object_in_taxonomy( $post_type, 'category' ) ) {
                wp_set_post_categories( $post_ID, $post_category );
        }

        if ( isset( $postarr['tags_input'] ) && is_object_in_taxonomy( $post_type, 'post_tag' ) ) {
                wp_set_post_tags( $post_ID, $postarr['tags_input'] );
        }

        // New-style support for all custom taxonomies.
        if ( ! empty( $postarr['tax_input'] ) ) {
                foreach ( $postarr['tax_input'] as $taxonomy => $tags ) {
                        $taxonomy_obj = get_taxonomy($taxonomy);
                        // array = hierarchical, string = non-hierarchical.
                        if ( is_array( $tags ) ) {
                                $tags = array_filter($tags);
                        }
                        if ( current_user_can( $taxonomy_obj->cap->assign_terms ) ) {
                                wp_set_post_terms( $post_ID, $tags, $taxonomy );
                        }
                }
        }

        $current_guid = get_post_field( 'guid', $post_ID );

        // Set GUID.
        if ( ! $update && '' == $current_guid ) {
                $wpdb->update( $wpdb->posts, array( 'guid' => get_permalink( $post_ID ) ), $where );
        }

        if ( 'attachment' === $postarr['post_type'] ) {
                if ( ! empty( $postarr['file'] ) ) {
                        update_attached_file( $post_ID, $postarr['file'] );
                }

                if ( ! empty( $postarr['context'] ) ) {
                        add_post_meta( $post_ID, '_wp_attachment_context', $postarr['context'], true );
                }
        }

        clean_post_cache( $post_ID );

        $post = get_post( $post_ID );

        if ( ! empty( $postarr['page_template'] ) && 'page' == $data['post_type'] ) {
                $post->page_template = $postarr['page_template'];
                $page_templates = wp_get_theme()->get_page_templates( $post );
                if ( 'default' != $postarr['page_template'] && ! isset( $page_templates[ $postarr['page_template'] ] ) ) {
                        if ( $wp_error ) {
                                return new WP_Error('invalid_page_template', __('The page template is invalid.'));
                        }
                        update_post_meta( $post_ID, '_wp_page_template', 'default' );
                } else {
                        update_post_meta( $post_ID, '_wp_page_template', $postarr['page_template'] );
                }
        }

        if ( 'attachment' !== $postarr['post_type'] ) {
                wp_transition_post_status( $data['post_status'], $previous_status, $post );
        } else {
                if ( $update ) {
                        /**
                         * Fires once an existing attachment has been updated.
                         *
                         * @since 2.0.0
                         *
                         * @param int $post_ID Attachment ID.
                         */
                        do_action( 'edit_attachment', $post_ID );
                } else {

                        /**
                         * Fires once an attachment has been added.
                         *
                         * @since 2.0.0
                         *
                         * @param int $post_ID Attachment ID.
                         */
                        do_action( 'add_attachment', $post_ID );
                }

                return $post_ID;
        }

        if ( $update ) {
                /**
                 * Fires once an existing post has been updated.
                 *
                 * @since 1.2.0
                 *
                 * @param int     $post_ID Post ID.
                 * @param WP_Post $post    Post object.
                 */
                do_action( 'edit_post', $post_ID, $post );
                $post_after = get_post($post_ID);

                /**
                 * Fires once an existing post has been updated.
                 *
                 * @since 3.0.0
                 *
                 * @param int     $post_ID      Post ID.
                 * @param WP_Post $post_after   Post object following the update.
                 * @param WP_Post $post_before  Post object before the update.
                 */
                do_action( 'post_updated', $post_ID, $post_after, $post_before);
        }

        /**
         * Fires once a post has been saved.
         *
         * The dynamic portion of the hook name, `$post->post_type`, refers to
         * the post type slug.
         *
         * @since 3.7.0
         *
         * @param int     $post_ID Post ID.
         * @param WP_Post $post    Post object.
         * @param bool    $update  Whether this is an existing post being updated or not.
         */
        do_action( "save_post_{$post->post_type}", $post_ID, $post, $update );

        /**
         * Fires once a post has been saved.
         *
         * @since 1.5.0
         *
         * @param int     $post_ID Post ID.
         * @param WP_Post $post    Post object.
         * @param bool    $update  Whether this is an existing post being updated or not.
         */
        do_action( 'save_post', $post_ID, $post, $update );

        /**
         * Fires once a post has been saved.
         *
         * @since 2.0.0
         *
         * @param int     $post_ID Post ID.
         * @param WP_Post $post    Post object.
         * @param bool    $update  Whether this is an existing post being updated or not.
         */
        do_action( 'wp_insert_post', $post_ID, $post, $update );

        return $post_ID;
}

/**
 * Update a post with new post data.
 *
 * The date does not have to be set for drafts. You can set the date and it will
 * not be overridden.
 *
 * @since 1.0.0
 *
 * @param array|object $postarr  Optional. Post data. Arrays are expected to be escaped,
 *                               objects are not. Default array.
 * @param bool         $wp_error Optional. Allow return of WP_Error on failure. Default false.
 * @return int|WP_Error The value 0 or WP_Error on failure. The post ID on success.
 */
function wp_update_post( $postarr = array(), $wp_error = false ) {
        if ( is_object($postarr) ) {
                // Non-escaped post was passed.
                $postarr = get_object_vars($postarr);
                $postarr = wp_slash($postarr);
        }

        // First, get all of the original fields.
        $post = get_post($postarr['ID'], ARRAY_A);

        if ( is_null( $post ) ) {
                if ( $wp_error )
                        return new WP_Error( 'invalid_post', __( 'Invalid post ID.' ) );
                return 0;
        }

        // Escape data pulled from DB.
        $post = wp_slash($post);

        // Passed post category list overwrites existing category list if not empty.
        if ( isset($postarr['post_category']) && is_array($postarr['post_category'])
                         && 0 != count($postarr['post_category']) )
                $post_cats = $postarr['post_category'];
        else
                $post_cats = $post['post_category'];

        // Drafts shouldn't be assigned a date unless explicitly done so by the user.
        if ( isset( $post['post_status'] ) && in_array($post['post_status'], array('draft', 'pending', 'auto-draft')) && empty($postarr['edit_date']) &&
                         ('0000-00-00 00:00:00' == $post['post_date_gmt']) )
                $clear_date = true;
        else
                $clear_date = false;

        // Merge old and new fields with new fields overwriting old ones.
        $postarr = array_merge($post, $postarr);
        $postarr['post_category'] = $post_cats;
        if ( $clear_date ) {
                $postarr['post_date'] = current_time('mysql');
                $postarr['post_date_gmt'] = '';
        }

        if ($postarr['post_type'] == 'attachment')
                return wp_insert_attachment($postarr);

        return wp_insert_post( $postarr, $wp_error );
}

/**
 * Publish a post by transitioning the post status.
 *
 * @since 2.1.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int|WP_Post $post Post ID or post object.
 */
function wp_publish_post( $post ) {
        global $wpdb;

        if ( ! $post = get_post( $post ) )
                return;

        if ( 'publish' == $post->post_status )
                return;

        $wpdb->update( $wpdb->posts, array( 'post_status' => 'publish' ), array( 'ID' => $post->ID ) );

        clean_post_cache( $post->ID );

        $old_status = $post->post_status;
        $post->post_status = 'publish';
        wp_transition_post_status( 'publish', $old_status, $post );

        /** This action is documented in wp-includes/post.php */
        do_action( 'edit_post', $post->ID, $post );

        /** This action is documented in wp-includes/post.php */
        do_action( "save_post_{$post->post_type}", $post->ID, $post, true );