+function __return_true() {
+ return true;
+}
+
+/**
+ * Returns false.
+ *
+ * Useful for returning false to filters easily.
+ *
+ * @since 3.0.0
+ *
+ * @see __return_true()
+ *
+ * @return bool False.
+ */
+function __return_false() {
+ return false;
+}
+
+/**
+ * Returns 0.
+ *
+ * Useful for returning 0 to filters easily.
+ *
+ * @since 3.0.0
+ *
+ * @return int 0.
+ */
+function __return_zero() {
+ return 0;
+}
+
+/**
+ * Returns an empty array.
+ *
+ * Useful for returning an empty array to filters easily.
+ *
+ * @since 3.0.0
+ *
+ * @return array Empty array.
+ */
+function __return_empty_array() {
+ return array();
+}
+
+/**
+ * Returns null.
+ *
+ * Useful for returning null to filters easily.
+ *
+ * @since 3.4.0
+ *
+ * @return null Null value.
+ */
+function __return_null() {
+ return null;
+}
+
+/**
+ * Returns an empty string.
+ *
+ * Useful for returning an empty string to filters easily.
+ *
+ * @since 3.7.0
+ *
+ * @see __return_null()
+ *
+ * @return string Empty string.
+ */
+function __return_empty_string() {
+ return '';
+}
+
+/**
+ * Send a HTTP header to disable content type sniffing in browsers which support it.
+ *
+ * @since 3.0.0
+ *
+ * @see http://blogs.msdn.com/ie/archive/2008/07/02/ie8-security-part-v-comprehensive-protection.aspx
+ * @see http://src.chromium.org/viewvc/chrome?view=rev&revision=6985
+ */
+function send_nosniff_header() {
+ @header( 'X-Content-Type-Options: nosniff' );
+}
+
+/**
+ * Return a MySQL expression for selecting the week number based on the start_of_week option.
+ *
+ * @internal
+ * @since 3.0.0
+ *
+ * @param string $column Database column.
+ * @return string SQL clause.
+ */
+function _wp_mysql_week( $column ) {
+ switch ( $start_of_week = (int) get_option( 'start_of_week' ) ) {
+ case 1 :
+ return "WEEK( $column, 1 )";
+ case 2 :
+ case 3 :
+ case 4 :
+ case 5 :
+ case 6 :
+ return "WEEK( DATE_SUB( $column, INTERVAL $start_of_week DAY ), 0 )";
+ case 0 :
+ default :
+ return "WEEK( $column, 0 )";
+ }
+}
+
+/**
+ * Find hierarchy loops using a callback function that maps object IDs to parent IDs.
+ *
+ * @since 3.1.0
+ * @access private
+ *
+ * @param callback $callback Function that accepts ( ID, $callback_args ) and outputs parent_ID.
+ * @param int $start The ID to start the loop check at.
+ * @param int $start_parent The parent_ID of $start to use instead of calling $callback( $start ).
+ * Use null to always use $callback
+ * @param array $callback_args Optional. Additional arguments to send to $callback.
+ * @return array IDs of all members of loop.
+ */
+function wp_find_hierarchy_loop( $callback, $start, $start_parent, $callback_args = array() ) {
+ $override = is_null( $start_parent ) ? array() : array( $start => $start_parent );
+
+ if ( !$arbitrary_loop_member = wp_find_hierarchy_loop_tortoise_hare( $callback, $start, $override, $callback_args ) )
+ return array();
+
+ return wp_find_hierarchy_loop_tortoise_hare( $callback, $arbitrary_loop_member, $override, $callback_args, true );
+}
+
+/**
+ * Use the "The Tortoise and the Hare" algorithm to detect loops.
+ *
+ * For every step of the algorithm, the hare takes two steps and the tortoise one.
+ * If the hare ever laps the tortoise, there must be a loop.
+ *
+ * @since 3.1.0
+ * @access private
+ *
+ * @param callback $callback Function that accepts ( ID, callback_arg, ... ) and outputs parent_ID.
+ * @param int $start The ID to start the loop check at.
+ * @param array $override Optional. An array of ( ID => parent_ID, ... ) to use instead of $callback.
+ * Default empty array.
+ * @param array $callback_args Optional. Additional arguments to send to $callback. Default empty array.
+ * @param bool $_return_loop Optional. Return loop members or just detect presence of loop? Only set
+ * to true if you already know the given $start is part of a loop (otherwise
+ * the returned array might include branches). Default false.
+ * @return mixed Scalar ID of some arbitrary member of the loop, or array of IDs of all members of loop if
+ * $_return_loop
+ */
+function wp_find_hierarchy_loop_tortoise_hare( $callback, $start, $override = array(), $callback_args = array(), $_return_loop = false ) {
+ $tortoise = $hare = $evanescent_hare = $start;
+ $return = array();
+
+ // Set evanescent_hare to one past hare
+ // Increment hare two steps
+ while (
+ $tortoise
+ &&
+ ( $evanescent_hare = isset( $override[$hare] ) ? $override[$hare] : call_user_func_array( $callback, array_merge( array( $hare ), $callback_args ) ) )
+ &&
+ ( $hare = isset( $override[$evanescent_hare] ) ? $override[$evanescent_hare] : call_user_func_array( $callback, array_merge( array( $evanescent_hare ), $callback_args ) ) )
+ ) {
+ if ( $_return_loop )
+ $return[$tortoise] = $return[$evanescent_hare] = $return[$hare] = true;
+
+ // tortoise got lapped - must be a loop
+ if ( $tortoise == $evanescent_hare || $tortoise == $hare )
+ return $_return_loop ? $return : $tortoise;
+
+ // Increment tortoise by one step
+ $tortoise = isset( $override[$tortoise] ) ? $override[$tortoise] : call_user_func_array( $callback, array_merge( array( $tortoise ), $callback_args ) );
+ }
+
+ return false;
+}
+
+/**
+ * Send a HTTP header to limit rendering of pages to same origin iframes.
+ *
+ * @since 3.1.3
+ *
+ * @see https://developer.mozilla.org/en/the_x-frame-options_response_header
+ */
+function send_frame_options_header() {
+ @header( 'X-Frame-Options: SAMEORIGIN' );
+}
+
+/**
+ * Retrieve a list of protocols to allow in HTML attributes.
+ *
+ * @since 3.3.0
+ *
+ * @see wp_kses()
+ * @see esc_url()
+ *
+ * @return array Array of allowed protocols.
+ */
+function wp_allowed_protocols() {
+ static $protocols;
+
+ if ( empty( $protocols ) ) {
+ $protocols = array( 'http', 'https', 'ftp', 'ftps', 'mailto', 'news', 'irc', 'gopher', 'nntp', 'feed', 'telnet', 'mms', 'rtsp', 'svn', 'tel', 'fax', 'xmpp' );
+
+ /**
+ * Filter the list of protocols allowed in HTML attributes.
+ *
+ * @since 3.0.0
+ *
+ * @param array $protocols Array of allowed protocols e.g. 'http', 'ftp', 'tel', and more.
+ */
+ $protocols = apply_filters( 'kses_allowed_protocols', $protocols );
+ }
+
+ return $protocols;
+}
+
+/**
+ * Return a comma-separated string of functions that have been called to get
+ * to the current point in code.
+ *
+ * @since 3.4.0
+ *
+ * @see https://core.trac.wordpress.org/ticket/19589
+ *
+ * @param string $ignore_class Optional. A class to ignore all function calls within - useful
+ * when you want to just give info about the callee. Default null.
+ * @param int $skip_frames Optional. A number of stack frames to skip - useful for unwinding
+ * back to the source of the issue. Default 0.
+ * @param bool $pretty Optional. Whether or not you want a comma separated string or raw
+ * array returned. Default true.
+ * @return string|array Either a string containing a reversed comma separated trace or an array
+ * of individual calls.
+ */
+function wp_debug_backtrace_summary( $ignore_class = null, $skip_frames = 0, $pretty = true ) {
+ if ( version_compare( PHP_VERSION, '5.2.5', '>=' ) )
+ $trace = debug_backtrace( false );
+ else
+ $trace = debug_backtrace();
+
+ $caller = array();
+ $check_class = ! is_null( $ignore_class );
+ $skip_frames++; // skip this function
+
+ foreach ( $trace as $call ) {
+ if ( $skip_frames > 0 ) {
+ $skip_frames--;
+ } elseif ( isset( $call['class'] ) ) {
+ if ( $check_class && $ignore_class == $call['class'] )
+ continue; // Filter out calls
+
+ $caller[] = "{$call['class']}{$call['type']}{$call['function']}";
+ } else {
+ if ( in_array( $call['function'], array( 'do_action', 'apply_filters' ) ) ) {
+ $caller[] = "{$call['function']}('{$call['args'][0]}')";
+ } elseif ( in_array( $call['function'], array( 'include', 'include_once', 'require', 'require_once' ) ) ) {
+ $caller[] = $call['function'] . "('" . str_replace( array( WP_CONTENT_DIR, ABSPATH ) , '', $call['args'][0] ) . "')";
+ } else {
+ $caller[] = $call['function'];
+ }
+ }
+ }
+ if ( $pretty )
+ return join( ', ', array_reverse( $caller ) );
+ else
+ return $caller;
+}
+
+/**
+ * Retrieve ids that are not already present in the cache.
+ *
+ * @since 3.4.0
+ * @access private
+ *
+ * @param array $object_ids ID list.
+ * @param string $cache_key The cache bucket to check against.
+ *
+ * @return array List of ids not present in the cache.
+ */
+function _get_non_cached_ids( $object_ids, $cache_key ) {
+ $clean = array();
+ foreach ( $object_ids as $id ) {
+ $id = (int) $id;
+ if ( !wp_cache_get( $id, $cache_key ) ) {
+ $clean[] = $id;
+ }
+ }
+
+ return $clean;
+}
+
+/**
+ * Test if the current device has the capability to upload files.
+ *
+ * @since 3.4.0
+ * @access private
+ *
+ * @return bool true|false Whether the device is able to upload files.
+ */
+function _device_can_upload() {
+ if ( ! wp_is_mobile() )
+ return true;
+
+ $ua = $_SERVER['HTTP_USER_AGENT'];
+
+ if ( strpos($ua, 'iPhone') !== false
+ || strpos($ua, 'iPad') !== false
+ || strpos($ua, 'iPod') !== false ) {
+ return preg_match( '#OS ([\d_]+) like Mac OS X#', $ua, $version ) && version_compare( $version[1], '6', '>=' );
+ }
+
+ return true;
+}
+
+/**
+ * Test if a given path is a stream URL
+ *
+ * @param string $path The resource path or URL.
+ * @return bool True if the path is a stream URL.
+ */
+function wp_is_stream( $path ) {
+ $wrappers = stream_get_wrappers();
+ $wrappers_re = '(' . join('|', $wrappers) . ')';
+
+ return preg_match( "!^$wrappers_re://!", $path ) === 1;
+}
+
+/**
+ * Test if the supplied date is valid for the Gregorian calendar.
+ *
+ * @since 3.5.0
+ *
+ * @see checkdate()
+ *
+ * @param int $month Month number.
+ * @param int $day Day number.
+ * @param int $year Year number.
+ * @param string $source_date The date to filter.
+ * @return bool True if valid date, false if not valid date.
+ */
+function wp_checkdate( $month, $day, $year, $source_date ) {
+ /**
+ * Filter whether the given date is valid for the Gregorian calendar.
+ *
+ * @since 3.5.0
+ *
+ * @param bool $checkdate Whether the given date is valid.
+ * @param string $source_date Date to check.
+ */
+ return apply_filters( 'wp_checkdate', checkdate( $month, $day, $year ), $source_date );
+}
+
+/**
+ * Load the auth check for monitoring whether the user is still logged in.
+ *
+ * Can be disabled with remove_action( 'admin_enqueue_scripts', 'wp_auth_check_load' );
+ *
+ * This is disabled for certain screens where a login screen could cause an
+ * inconvenient interruption. A filter called wp_auth_check_load can be used
+ * for fine-grained control.
+ *
+ * @since 3.6.0
+ */
+function wp_auth_check_load() {
+ if ( ! is_admin() && ! is_user_logged_in() )
+ return;
+
+ if ( defined( 'IFRAME_REQUEST' ) )
+ return;
+
+ $screen = get_current_screen();
+ $hidden = array( 'update', 'update-network', 'update-core', 'update-core-network', 'upgrade', 'upgrade-network', 'network' );
+ $show = ! in_array( $screen->id, $hidden );
+
+ /**
+ * Filter whether to load the authentication check.
+ *
+ * Passing a falsey value to the filter will effectively short-circuit
+ * loading the authentication check.
+ *
+ * @since 3.6.0
+ *
+ * @param bool $show Whether to load the authentication check.
+ * @param WP_Screen $screen The current screen object.
+ */
+ if ( apply_filters( 'wp_auth_check_load', $show, $screen ) ) {
+ wp_enqueue_style( 'wp-auth-check' );
+ wp_enqueue_script( 'wp-auth-check' );
+
+ add_action( 'admin_print_footer_scripts', 'wp_auth_check_html', 5 );
+ add_action( 'wp_print_footer_scripts', 'wp_auth_check_html', 5 );
+ }
+}
+
+/**
+ * Output the HTML that shows the wp-login dialog when the user is no longer logged in.
+ *
+ * @since 3.6.0
+ */
+function wp_auth_check_html() {
+ $login_url = wp_login_url();
+ $current_domain = ( is_ssl() ? 'https://' : 'http://' ) . $_SERVER['HTTP_HOST'];
+ $same_domain = ( strpos( $login_url, $current_domain ) === 0 );
+
+ /**
+ * Filter whether the authentication check originated at the same domain.
+ *
+ * @since 3.6.0
+ *
+ * @param bool $same_domain Whether the authentication check originated at the same domain.
+ */
+ $same_domain = apply_filters( 'wp_auth_check_same_domain', $same_domain );
+ $wrap_class = $same_domain ? 'hidden' : 'hidden fallback';
+
+ ?>
+ <div id="wp-auth-check-wrap" class="<?php echo $wrap_class; ?>">
+ <div id="wp-auth-check-bg"></div>
+ <div id="wp-auth-check">
+ <div class="wp-auth-check-close" tabindex="0" title="<?php esc_attr_e('Close'); ?>"></div>
+ <?php
+
+ if ( $same_domain ) {
+ ?>
+ <div id="wp-auth-check-form" data-src="<?php echo esc_url( add_query_arg( array( 'interim-login' => 1 ), $login_url ) ); ?>"></div>
+ <?php
+ }
+
+ ?>
+ <div class="wp-auth-fallback">
+ <p><b class="wp-auth-fallback-expired" tabindex="0"><?php _e('Session expired'); ?></b></p>
+ <p><a href="<?php echo esc_url( $login_url ); ?>" target="_blank"><?php _e('Please log in again.'); ?></a>
+ <?php _e('The login page will open in a new window. After logging in you can close it and return to this page.'); ?></p>
+ </div>
+ </div>
+ </div>
+ <?php
+}
+
+/**
+ * Check whether a user is still logged in, for the heartbeat.
+ *
+ * Send a result that shows a log-in box if the user is no longer logged in,
+ * or if their cookie is within the grace period.
+ *
+ * @since 3.6.0
+ *
+ * @param array|object $response The Heartbeat response object or array.
+ * @return array|object $response The Heartbeat response object or array with 'wp-auth-check'
+ * value set.
+ */
+function wp_auth_check( $response ) {
+ $response['wp-auth-check'] = is_user_logged_in() && empty( $GLOBALS['login_grace_period'] );
+ return $response;
+}
+
+/**
+ * Return RegEx body to liberally match an opening HTML tag.
+ *
+ * Matches an opening HTML tag that:
+ * 1. Is self-closing or
+ * 2. Has no body but has a closing tag of the same name or
+ * 3. Contains a body and a closing tag of the same name
+ *
+ * Note: this RegEx does not balance inner tags and does not attempt
+ * to produce valid HTML
+ *
+ * @since 3.6.0
+ *
+ * @param string $tag An HTML tag name. Example: 'video'.
+ * @return string Tag RegEx.
+ */
+function get_tag_regex( $tag ) {
+ if ( empty( $tag ) )
+ return;
+ return sprintf( '<%1$s[^<]*(?:>[\s\S]*<\/%1$s>|\s*\/>)', tag_escape( $tag ) );
+}
+
+/**
+ * Retrieve a canonical form of the provided charset appropriate for passing to PHP
+ * functions such as htmlspecialchars() and charset html attributes.
+ *
+ * @since 3.6.0
+ * @access private
+ *
+ * @see https://core.trac.wordpress.org/ticket/23688
+ *
+ * @param string $charset A charset name.
+ * @return string The canonical form of the charset.
+ */
+function _canonical_charset( $charset ) {
+ if ( 'UTF-8' === $charset || 'utf-8' === $charset || 'utf8' === $charset ||
+ 'UTF8' === $charset )
+ return 'UTF-8';
+
+ if ( 'ISO-8859-1' === $charset || 'iso-8859-1' === $charset ||
+ 'iso8859-1' === $charset || 'ISO8859-1' === $charset )
+ return 'ISO-8859-1';
+
+ return $charset;
+}
+
+/**
+ * Set the mbstring internal encoding to a binary safe encoding when func_overload
+ * is enabled.
+ *
+ * When mbstring.func_overload is in use for multi-byte encodings, the results from
+ * strlen() and similar functions respect the utf8 characters, causing binary data
+ * to return incorrect lengths.
+ *
+ * This function overrides the mbstring encoding to a binary-safe encoding, and
+ * resets it to the users expected encoding afterwards through the
+ * `reset_mbstring_encoding` function.
+ *
+ * It is safe to recursively call this function, however each
+ * `mbstring_binary_safe_encoding()` call must be followed up with an equal number
+ * of `reset_mbstring_encoding()` calls.
+ *
+ * @since 3.7.0
+ *
+ * @see reset_mbstring_encoding()
+ *
+ * @param bool $reset Optional. Whether to reset the encoding back to a previously-set encoding.
+ * Default false.
+ */
+function mbstring_binary_safe_encoding( $reset = false ) {
+ static $encodings = array();
+ static $overloaded = null;
+
+ if ( is_null( $overloaded ) )
+ $overloaded = function_exists( 'mb_internal_encoding' ) && ( ini_get( 'mbstring.func_overload' ) & 2 );
+
+ if ( false === $overloaded )
+ return;
+
+ if ( ! $reset ) {
+ $encoding = mb_internal_encoding();
+ array_push( $encodings, $encoding );
+ mb_internal_encoding( 'ISO-8859-1' );
+ }
+
+ if ( $reset && $encodings ) {
+ $encoding = array_pop( $encodings );
+ mb_internal_encoding( $encoding );
+ }
+}
+
+/**
+ * Reset the mbstring internal encoding to a users previously set encoding.
+ *
+ * @see mbstring_binary_safe_encoding()
+ *
+ * @since 3.7.0
+ */
+function reset_mbstring_encoding() {
+ mbstring_binary_safe_encoding( true );
+}
+
+/**
+ * Filter/validate a variable as a boolean.
+ *
+ * Alternative to `filter_var( $var, FILTER_VALIDATE_BOOLEAN )`.
+ *
+ * @since 4.0.0
+ *
+ * @param mixed $var Boolean value to validate.
+ * @return bool Whether the value is validated.
+ */
+function wp_validate_boolean( $var ) {
+ if ( is_bool( $var ) ) {
+ return $var;
+ }
+
+ if ( is_string( $var ) && 'false' === strtolower( $var ) ) {
+ return false;
+ }
+
+ return (bool) $var;