Adding upstream version 6.4.3+dfsg1.upstream/6.4.3+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1257 insertions, 0 deletions

diff --git a/wp-includes/query.php b/wp-includes/query.php
new file mode 100644
index 0000000..94c6453
--- /dev/null
+++ b/wp-includes/query.php
@@ -0,0 +1,1257 @@
+<?php
+/**
+ * WordPress Query API
+ *
+ * The query API attempts to get which part of WordPress the user is on. It
+ * also provides functionality for getting URL query information.
+ *
+ * @link https://developer.wordpress.org/themes/basics/the-loop/ More information on The Loop.
+ *
+ * @package WordPress
+ * @subpackage Query
+ */
+
+/**
+ * Retrieves the value of a query variable in the WP_Query class.
+ *
+ * @since 1.5.0
+ * @since 3.9.0 The `$default_value` argument was introduced.
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param string $query_var     The variable key to retrieve.
+ * @param mixed  $default_value Optional. Value to return if the query variable is not set.
+ *                              Default empty string.
+ * @return mixed Contents of the query variable.
+ */
+function get_query_var( $query_var, $default_value = '' ) {
+	global $wp_query;
+	return $wp_query->get( $query_var, $default_value );
+}
+
+/**
+ * Retrieves the currently queried object.
+ *
+ * Wrapper for WP_Query::get_queried_object().
+ *
+ * @since 3.1.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return WP_Term|WP_Post_Type|WP_Post|WP_User|null The queried object.
+ */
+function get_queried_object() {
+	global $wp_query;
+	return $wp_query->get_queried_object();
+}
+
+/**
+ * Retrieves the ID of the currently queried object.
+ *
+ * Wrapper for WP_Query::get_queried_object_id().
+ *
+ * @since 3.1.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return int ID of the queried object.
+ */
+function get_queried_object_id() {
+	global $wp_query;
+	return $wp_query->get_queried_object_id();
+}
+
+/**
+ * Sets the value of a query variable in the WP_Query class.
+ *
+ * @since 2.2.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param string $query_var Query variable key.
+ * @param mixed  $value     Query variable value.
+ */
+function set_query_var( $query_var, $value ) {
+	global $wp_query;
+	$wp_query->set( $query_var, $value );
+}
+
+/**
+ * Sets up The Loop with query parameters.
+ *
+ * Note: This function will completely override the main query and isn't intended for use
+ * by plugins or themes. Its overly-simplistic approach to modifying the main query can be
+ * problematic and should be avoided wherever possible. In most cases, there are better,
+ * more performant options for modifying the main query such as via the {@see 'pre_get_posts'}
+ * action within WP_Query.
+ *
+ * This must not be used within the WordPress Loop.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param array|string $query Array or string of WP_Query arguments.
+ * @return WP_Post[]|int[] Array of post objects or post IDs.
+ */
+function query_posts( $query ) {
+	$GLOBALS['wp_query'] = new WP_Query();
+	return $GLOBALS['wp_query']->query( $query );
+}
+
+/**
+ * Destroys the previous query and sets up a new query.
+ *
+ * This should be used after query_posts() and before another query_posts().
+ * This will remove obscure bugs that occur when the previous WP_Query object
+ * is not destroyed properly before another is set up.
+ *
+ * @since 2.3.0
+ *
+ * @global WP_Query $wp_query     WordPress Query object.
+ * @global WP_Query $wp_the_query Copy of the global WP_Query instance created during wp_reset_query().
+ */
+function wp_reset_query() {
+	$GLOBALS['wp_query'] = $GLOBALS['wp_the_query'];
+	wp_reset_postdata();
+}
+
+/**
+ * After looping through a separate query, this function restores
+ * the $post global to the current post in the main query.
+ *
+ * @since 3.0.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ */
+function wp_reset_postdata() {
+	global $wp_query;
+
+	if ( isset( $wp_query ) ) {
+		$wp_query->reset_postdata();
+	}
+}
+
+/*
+ * Query type checks.
+ */
+
+/**
+ * Determines whether the query is for an existing archive page.
+ *
+ * Archive pages include category, tag, author, date, custom post type,
+ * and custom taxonomy based archives.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @see is_category()
+ * @see is_tag()
+ * @see is_author()
+ * @see is_date()
+ * @see is_post_type_archive()
+ * @see is_tax()
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for an existing archive page.
+ */
+function is_archive() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_archive();
+}
+
+/**
+ * Determines whether the query is for an existing post type archive page.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 3.1.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param string|string[] $post_types Optional. Post type or array of posts types
+ *                                    to check against. Default empty.
+ * @return bool Whether the query is for an existing post type archive page.
+ */
+function is_post_type_archive( $post_types = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_post_type_archive( $post_types );
+}
+
+/**
+ * Determines whether the query is for an existing attachment page.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 2.0.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param int|string|int[]|string[] $attachment Optional. Attachment ID, title, slug, or array of such
+ *                                              to check against. Default empty.
+ * @return bool Whether the query is for an existing attachment page.
+ */
+function is_attachment( $attachment = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_attachment( $attachment );
+}
+
+/**
+ * Determines whether the query is for an existing author archive page.
+ *
+ * If the $author parameter is specified, this function will additionally
+ * check if the query is for one of the authors specified.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param int|string|int[]|string[] $author Optional. User ID, nickname, nicename, or array of such
+ *                                          to check against. Default empty.
+ * @return bool Whether the query is for an existing author archive page.
+ */
+function is_author( $author = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_author( $author );
+}
+
+/**
+ * Determines whether the query is for an existing category archive page.
+ *
+ * If the $category parameter is specified, this function will additionally
+ * check if the query is for one of the categories specified.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param int|string|int[]|string[] $category Optional. Category ID, name, slug, or array of such
+ *                                            to check against. Default empty.
+ * @return bool Whether the query is for an existing category archive page.
+ */
+function is_category( $category = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_category( $category );
+}
+
+/**
+ * Determines whether the query is for an existing tag archive page.
+ *
+ * If the $tag parameter is specified, this function will additionally
+ * check if the query is for one of the tags specified.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 2.3.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param int|string|int[]|string[] $tag Optional. Tag ID, name, slug, or array of such
+ *                                       to check against. Default empty.
+ * @return bool Whether the query is for an existing tag archive page.
+ */
+function is_tag( $tag = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_tag( $tag );
+}
+
+/**
+ * Determines whether the query is for an existing custom taxonomy archive page.
+ *
+ * If the $taxonomy parameter is specified, this function will additionally
+ * check if the query is for that specific $taxonomy.
+ *
+ * If the $term parameter is specified in addition to the $taxonomy parameter,
+ * this function will additionally check if the query is for one of the terms
+ * specified.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 2.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param string|string[]           $taxonomy Optional. Taxonomy slug or slugs to check against.
+ *                                            Default empty.
+ * @param int|string|int[]|string[] $term     Optional. Term ID, name, slug, or array of such
+ *                                            to check against. Default empty.
+ * @return bool Whether the query is for an existing custom taxonomy archive page.
+ *              True for custom taxonomy archive pages, false for built-in taxonomies
+ *              (category and tag archives).
+ */
+function is_tax( $taxonomy = '', $term = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_tax( $taxonomy, $term );
+}
+
+/**
+ * Determines whether the query is for an existing date archive.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for an existing date archive.
+ */
+function is_date() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_date();
+}
+
+/**
+ * Determines whether the query is for an existing day archive.
+ *
+ * A conditional check to test whether the page is a date-based archive page displaying posts for the current day.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for an existing day archive.
+ */
+function is_day() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_day();
+}
+
+/**
+ * Determines whether the query is for a feed.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param string|string[] $feeds Optional. Feed type or array of feed types
+ *                                         to check against. Default empty.
+ * @return bool Whether the query is for a feed.
+ */
+function is_feed( $feeds = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_feed( $feeds );
+}
+
+/**
+ * Is the query for a comments feed?
+ *
+ * @since 3.0.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for a comments feed.
+ */
+function is_comment_feed() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_comment_feed();
+}
+
+/**
+ * Determines whether the query is for the front page of the site.
+ *
+ * This is for what is displayed at your site's main URL.
+ *
+ * Depends on the site's "Front page displays" Reading Settings 'show_on_front' and 'page_on_front'.
+ *
+ * If you set a static page for the front page of your site, this function will return
+ * true when viewing that page.
+ *
+ * Otherwise the same as {@see is_home()}.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 2.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for the front page of the site.
+ */
+function is_front_page() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_front_page();
+}
+
+/**
+ * Determines whether the query is for the blog homepage.
+ *
+ * The blog homepage is the page that shows the time-based blog content of the site.
+ *
+ * is_home() is dependent on the site's "Front page displays" Reading Settings 'show_on_front'
+ * and 'page_for_posts'.
+ *
+ * If a static page is set for the front page of the site, this function will return true only
+ * on the page you set as the "Posts page".
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @see is_front_page()
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for the blog homepage.
+ */
+function is_home() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_home();
+}
+
+/**
+ * Determines whether the query is for the Privacy Policy page.
+ *
+ * The Privacy Policy page is the page that shows the Privacy Policy content of the site.
+ *
+ * is_privacy_policy() is dependent on the site's "Change your Privacy Policy page" Privacy Settings 'wp_page_for_privacy_policy'.
+ *
+ * This function will return true only on the page you set as the "Privacy Policy page".
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 5.2.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for the Privacy Policy page.
+ */
+function is_privacy_policy() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_privacy_policy();
+}
+
+/**
+ * Determines whether the query is for an existing month archive.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for an existing month archive.
+ */
+function is_month() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_month();
+}
+
+/**
+ * Determines whether the query is for an existing single page.
+ *
+ * If the $page parameter is specified, this function will additionally
+ * check if the query is for one of the pages specified.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @see is_single()
+ * @see is_singular()
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param int|string|int[]|string[] $page Optional. Page ID, title, slug, or array of such
+ *                                        to check against. Default empty.
+ * @return bool Whether the query is for an existing single page.
+ */
+function is_page( $page = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_page( $page );
+}
+
+/**
+ * Determines whether the query is for a paged result and not for the first page.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for a paged result.
+ */
+function is_paged() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_paged();
+}
+
+/**
+ * Determines whether the query is for a post or page preview.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 2.0.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for a post or page preview.
+ */
+function is_preview() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_preview();
+}
+
+/**
+ * Is the query for the robots.txt file?
+ *
+ * @since 2.1.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for the robots.txt file.
+ */
+function is_robots() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_robots();
+}
+
+/**
+ * Is the query for the favicon.ico file?
+ *
+ * @since 5.4.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for the favicon.ico file.
+ */
+function is_favicon() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_favicon();
+}
+
+/**
+ * Determines whether the query is for a search.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for a search.
+ */
+function is_search() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_search();
+}
+
+/**
+ * Determines whether the query is for an existing single post.
+ *
+ * Works for any post type, except attachments and pages
+ *
+ * If the $post parameter is specified, this function will additionally
+ * check if the query is for one of the Posts specified.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @see is_page()
+ * @see is_singular()
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param int|string|int[]|string[] $post Optional. Post ID, title, slug, or array of such
+ *                                        to check against. Default empty.
+ * @return bool Whether the query is for an existing single post.
+ */
+function is_single( $post = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_single( $post );
+}
+
+/**
+ * Determines whether the query is for an existing single post of any post type
+ * (post, attachment, page, custom post types).
+ *
+ * If the $post_types parameter is specified, this function will additionally
+ * check if the query is for one of the Posts Types specified.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @see is_page()
+ * @see is_single()
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param string|string[] $post_types Optional. Post type or array of post types
+ *                                    to check against. Default empty.
+ * @return bool Whether the query is for an existing single post
+ *              or any of the given post types.
+ */
+function is_singular( $post_types = '' ) {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_singular( $post_types );
+}
+
+/**
+ * Determines whether the query is for a specific time.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for a specific time.
+ */
+function is_time() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_time();
+}
+
+/**
+ * Determines whether the query is for a trackback endpoint call.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for a trackback endpoint call.
+ */
+function is_trackback() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_trackback();
+}
+
+/**
+ * Determines whether the query is for an existing year archive.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for an existing year archive.
+ */
+function is_year() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_year();
+}
+
+/**
+ * Determines whether the query has resulted in a 404 (returns no results).
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is a 404 error.
+ */
+function is_404() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_404();
+}
+
+/**
+ * Is the query for an embedded post?
+ *
+ * @since 4.4.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is for an embedded post.
+ */
+function is_embed() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
+		return false;
+	}
+
+	return $wp_query->is_embed();
+}
+
+/**
+ * Determines whether the query is the main query.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 3.3.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool Whether the query is the main query.
+ */
+function is_main_query() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '6.1.0' );
+		return false;
+	}
+
+	if ( 'pre_get_posts' === current_filter() ) {
+		_doing_it_wrong(
+			__FUNCTION__,
+			sprintf(
+				/* translators: 1: pre_get_posts, 2: WP_Query->is_main_query(), 3: is_main_query(), 4: Documentation URL. */
+				__( 'In %1$s, use the %2$s method, not the %3$s function. See %4$s.' ),
+				'<code>pre_get_posts</code>',
+				'<code>WP_Query->is_main_query()</code>',
+				'<code>is_main_query()</code>',
+				__( 'https://developer.wordpress.org/reference/functions/is_main_query/' )
+			),
+			'3.7.0'
+		);
+	}
+
+	return $wp_query->is_main_query();
+}
+
+/*
+ * The Loop. Post loop control.
+ */
+
+/**
+ * Determines whether current WordPress query has posts to loop over.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool True if posts are available, false if end of the loop.
+ */
+function have_posts() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		return false;
+	}
+
+	return $wp_query->have_posts();
+}
+
+/**
+ * Determines whether the caller is in the Loop.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 2.0.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool True if caller is within loop, false if loop hasn't started or ended.
+ */
+function in_the_loop() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		return false;
+	}
+
+	return $wp_query->in_the_loop;
+}
+
+/**
+ * Rewind the loop posts.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ */
+function rewind_posts() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		return;
+	}
+
+	$wp_query->rewind_posts();
+}
+
+/**
+ * Iterate the post index in the loop.
+ *
+ * @since 1.5.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ */
+function the_post() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		return;
+	}
+
+	$wp_query->the_post();
+}
+
+/*
+ * Comments loop.
+ */
+
+/**
+ * Determines whether current WordPress query has comments to loop over.
+ *
+ * @since 2.2.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @return bool True if comments are available, false if no more comments.
+ */
+function have_comments() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		return false;
+	}
+
+	return $wp_query->have_comments();
+}
+
+/**
+ * Iterate comment index in the comment loop.
+ *
+ * @since 2.2.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ */
+function the_comment() {
+	global $wp_query;
+
+	if ( ! isset( $wp_query ) ) {
+		return;
+	}
+
+	$wp_query->the_comment();
+}
+
+/**
+ * Redirect old slugs to the correct permalink.
+ *
+ * Attempts to find the current slug from the past slugs.
+ *
+ * @since 2.1.0
+ */
+function wp_old_slug_redirect() {
+	if ( is_404() && '' !== get_query_var( 'name' ) ) {
+		// Guess the current post type based on the query vars.
+		if ( get_query_var( 'post_type' ) ) {
+			$post_type = get_query_var( 'post_type' );
+		} elseif ( get_query_var( 'attachment' ) ) {
+			$post_type = 'attachment';
+		} elseif ( get_query_var( 'pagename' ) ) {
+			$post_type = 'page';
+		} else {
+			$post_type = 'post';
+		}
+
+		if ( is_array( $post_type ) ) {
+			if ( count( $post_type ) > 1 ) {
+				return;
+			}
+			$post_type = reset( $post_type );
+		}
+
+		// Do not attempt redirect for hierarchical post types.
+		if ( is_post_type_hierarchical( $post_type ) ) {
+			return;
+		}
+
+		$id = _find_post_by_old_slug( $post_type );
+
+		if ( ! $id ) {
+			$id = _find_post_by_old_date( $post_type );
+		}
+
+		/**
+		 * Filters the old slug redirect post ID.
+		 *
+		 * @since 4.9.3
+		 *
+		 * @param int $id The redirect post ID.
+		 */
+		$id = apply_filters( 'old_slug_redirect_post_id', $id );
+
+		if ( ! $id ) {
+			return;
+		}
+
+		$link = get_permalink( $id );
+
+		if ( get_query_var( 'paged' ) > 1 ) {
+			$link = user_trailingslashit( trailingslashit( $link ) . 'page/' . get_query_var( 'paged' ) );
+		} elseif ( is_embed() ) {
+			$link = user_trailingslashit( trailingslashit( $link ) . 'embed' );
+		}
+
+		/**
+		 * Filters the old slug redirect URL.
+		 *
+		 * @since 4.4.0
+		 *
+		 * @param string $link The redirect URL.
+		 */
+		$link = apply_filters( 'old_slug_redirect_url', $link );
+
+		if ( ! $link ) {
+			return;
+		}
+
+		wp_redirect( $link, 301 ); // Permanent redirect.
+		exit;
+	}
+}
+
+/**
+ * Find the post ID for redirecting an old slug.
+ *
+ * @since 4.9.3
+ * @access private
+ *
+ * @see wp_old_slug_redirect()
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
+ * @param string $post_type The current post type based on the query vars.
+ * @return int The Post ID.
+ */
+function _find_post_by_old_slug( $post_type ) {
+	global $wpdb;
+
+	$query = $wpdb->prepare( "SELECT post_id FROM $wpdb->postmeta, $wpdb->posts WHERE ID = post_id AND post_type = %s AND meta_key = '_wp_old_slug' AND meta_value = %s", $post_type, get_query_var( 'name' ) );
+
+	/*
+	 * If year, monthnum, or day have been specified, make our query more precise
+	 * just in case there are multiple identical _wp_old_slug values.
+	 */
+	if ( get_query_var( 'year' ) ) {
+		$query .= $wpdb->prepare( ' AND YEAR(post_date) = %d', get_query_var( 'year' ) );
+	}
+	if ( get_query_var( 'monthnum' ) ) {
+		$query .= $wpdb->prepare( ' AND MONTH(post_date) = %d', get_query_var( 'monthnum' ) );
+	}
+	if ( get_query_var( 'day' ) ) {
+		$query .= $wpdb->prepare( ' AND DAYOFMONTH(post_date) = %d', get_query_var( 'day' ) );
+	}
+
+	$key          = md5( $query );
+	$last_changed = wp_cache_get_last_changed( 'posts' );
+	$cache_key    = "find_post_by_old_slug:$key:$last_changed";
+	$cache        = wp_cache_get( $cache_key, 'post-queries' );
+	if ( false !== $cache ) {
+		$id = $cache;
+	} else {
+		$id = (int) $wpdb->get_var( $query );
+		wp_cache_set( $cache_key, $id, 'post-queries' );
+	}
+
+	return $id;
+}
+
+/**
+ * Find the post ID for redirecting an old date.
+ *
+ * @since 4.9.3
+ * @access private
+ *
+ * @see wp_old_slug_redirect()
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
+ * @param string $post_type The current post type based on the query vars.
+ * @return int The Post ID.
+ */
+function _find_post_by_old_date( $post_type ) {
+	global $wpdb;
+
+	$date_query = '';
+	if ( get_query_var( 'year' ) ) {
+		$date_query .= $wpdb->prepare( ' AND YEAR(pm_date.meta_value) = %d', get_query_var( 'year' ) );
+	}
+	if ( get_query_var( 'monthnum' ) ) {
+		$date_query .= $wpdb->prepare( ' AND MONTH(pm_date.meta_value) = %d', get_query_var( 'monthnum' ) );
+	}
+	if ( get_query_var( 'day' ) ) {
+		$date_query .= $wpdb->prepare( ' AND DAYOFMONTH(pm_date.meta_value) = %d', get_query_var( 'day' ) );
+	}
+
+	$id = 0;
+	if ( $date_query ) {
+		$query        = $wpdb->prepare( "SELECT post_id FROM $wpdb->postmeta AS pm_date, $wpdb->posts WHERE ID = post_id AND post_type = %s AND meta_key = '_wp_old_date' AND post_name = %s" . $date_query, $post_type, get_query_var( 'name' ) );
+		$key          = md5( $query );
+		$last_changed = wp_cache_get_last_changed( 'posts' );
+		$cache_key    = "find_post_by_old_date:$key:$last_changed";
+		$cache        = wp_cache_get( $cache_key, 'post-queries' );
+		if ( false !== $cache ) {
+			$id = $cache;
+		} else {
+			$id = (int) $wpdb->get_var( $query );
+			if ( ! $id ) {
+				// Check to see if an old slug matches the old date.
+				$id = (int) $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts, $wpdb->postmeta AS pm_slug, $wpdb->postmeta AS pm_date WHERE ID = pm_slug.post_id AND ID = pm_date.post_id AND post_type = %s AND pm_slug.meta_key = '_wp_old_slug' AND pm_slug.meta_value = %s AND pm_date.meta_key = '_wp_old_date'" . $date_query, $post_type, get_query_var( 'name' ) ) );
+			}
+			wp_cache_set( $cache_key, $id, 'post-queries' );
+		}
+	}
+
+	return $id;
+}
+
+/**
+ * Set up global post data.
+ *
+ * @since 1.5.0
+ * @since 4.4.0 Added the ability to pass a post ID to `$post`.
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param WP_Post|object|int $post WP_Post instance or Post ID/object.
+ * @return bool True when finished.
+ */
+function setup_postdata( $post ) {
+	global $wp_query;
+
+	if ( ! empty( $wp_query ) && $wp_query instanceof WP_Query ) {
+		return $wp_query->setup_postdata( $post );
+	}
+
+	return false;
+}
+
+/**
+ * Generates post data.
+ *
+ * @since 5.2.0
+ *
+ * @global WP_Query $wp_query WordPress Query object.
+ *
+ * @param WP_Post|object|int $post WP_Post instance or Post ID/object.
+ * @return array|false Elements of post, or false on failure.
+ */
+function generate_postdata( $post ) {
+	global $wp_query;
+
+	if ( ! empty( $wp_query ) && $wp_query instanceof WP_Query ) {
+		return $wp_query->generate_postdata( $post );
+	}
+
+	return false;
+}