eturn 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, 'posts' );
	if ( false !== $cache ) {
		$id = $cache;
	} else {
		$id = (int) $wpdb->get_var( $query );
		wp_cache_set( $cache_key, $id, 'posts' );
	}

	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, 'posts' );
		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, 'posts' );
		}
	}

	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;
}