Make get_adjacent_post() wrap a new WP_Get_Adjacent_Post object that uses WP_Query. (33b365fb) · Commits · singing-chimes.co.uk / wordpress-core

wp-includes/link-template.php

+256 −55

Original line number	Diff line number	Diff line
		@@ -1119,82 +1119,283 @@ function get_next_post( $in_same_term = false, $excluded_terms = '', $taxonomy =
		* @param array\|string $excluded_terms Optional. Array or comma-separated list of excluded term IDs.
		* @param bool $previous Optional. Whether to retrieve previous post.
		* @param string $taxonomy Optional. Taxonomy, if $in_same_term is true. Default 'category'.
		* @return mixed Post object if successful. Null if global $post is not set. Empty string if no corresponding post exists.
		* @return mixed Post object if successful. Null if current post doesn't exist. Empty string if no corresponding adjacent post exists.
		*/
		function get_adjacent_post( $in_same_term = false, $excluded_terms = '', $previous = true, $taxonomy = 'category' ) {
		global $wpdb;
		if ( is_string( $excluded_terms ) && false !== strpos( $excluded_terms, ' and ' ) ) {
		// back-compat: $excluded_terms used to be IDs separated by " and "
		_deprecated_argument( __FUNCTION__, '3.3', sprintf( __( 'Use commas instead of %s to separate excluded terms.' ), "'and'" ) );
		$excluded_terms = explode( ' and ', $excluded_terms );
		}
		if ( $excluded_terms ) {
		$excluded_terms = wp_parse_id_list( $excluded_terms );
		} else {
		$excluded_terms = array();
		}

		if ( ( ! $post = get_post() ) \|\| ! taxonomy_exists( $taxonomy ) )
		return null;
		$adjacent = new WP_Get_Adjacent_Post( array(
		'post' => get_post(),
		'previous' => $previous,
		'taxonomy' => $taxonomy,
		'in_same_term' => $in_same_term,
		'excluded_terms' => $excluded_terms,
		) );

		$current_post_date = $post->post_date;
		return $adjacent->adjacent_post;
		}

		$join = '';
		$posts_in_ex_terms_sql = '';
		if ( $in_same_term \|\| ! empty( $excluded_terms ) ) {
		$join = " INNER JOIN $wpdb->term_relationships AS tr ON p.ID = tr.object_id INNER JOIN $wpdb->term_taxonomy tt ON tr.term_taxonomy_id = tt.term_taxonomy_id";
		/**
		* WordPress Adjacent Post API
		*
		* Based on the current or specified post, determines either the previous or
		* next post based on the criteria specified. Supports retrieving posts with the
		* same taxonomy terms and posts that lack specific terms.
		*/
		class WP_Get_Adjacent_Post {
		public $adjacent_post = null;

		if ( $in_same_term ) {
		if ( ! is_object_in_taxonomy( $post->post_type, $taxonomy ) )
		return '';
		$term_array = wp_get_object_terms( $post->ID, $taxonomy, array( 'fields' => 'ids' ) );
		if ( ! $term_array \|\| is_wp_error( $term_array ) )
		return '';
		$join .= $wpdb->prepare( " AND tt.taxonomy = %s AND tt.term_id IN (" . implode( ',', array_map( 'intval', $term_array ) ) . ")", $taxonomy );
		protected $current_post = false;
		protected $adjacent = 'previous';
		protected $taxonomy = 'category';
		protected $in_same_term = false;
		protected $excluded_terms = '';

		/**
		* Class constructor.
		*
		* The post is queried is run if arguments are passed to the constructor.
		* Otherwise, the get_post() method will need to be called.
		*
		* @param array $args Optional. See the get_post() method for $args.
		*/
		public function __construct( $args = array() ) {
		if ( empty( $args ) ) {
		return;
		}

		$posts_in_ex_terms_sql = $wpdb->prepare( "AND tt.taxonomy = %s", $taxonomy );
		if ( ! empty( $excluded_terms ) ) {
		if ( ! is_array( $excluded_terms ) ) {
		// back-compat, $excluded_terms used to be $excluded_terms with IDs separated by " and "
		if ( false !== strpos( $excluded_terms, ' and ' ) ) {
		_deprecated_argument( __FUNCTION__, '3.3', sprintf( __( 'Use commas instead of %s to separate excluded terms.' ), "'and'" ) );
		$excluded_terms = explode( ' and ', $excluded_terms );
		$this->get_post( $args );
		}

		/**
		* Allow direct access to adjacent post from the class instance itself
		*
		* @param string $property
		* @return mixed String when adjacent post is found and post property exists. Null when no adjacent post is found.
		*/
		public function __get( $property ) {
		if ( is_object( $this->adjacent_post ) && property_exists( $this->adjacent_post, $property ) ) {
		return $this->adjacent_post->{$property};
		} else {
		$excluded_terms = explode( ',', $excluded_terms );
		return null;
		}
		}

		$excluded_terms = array_map( 'intval', $excluded_terms );
		/**
		* Determine adjacent post for specified post and adjacency.
		*
		* @since 3.9.0
		*
		* @param array $args {
		* Arguments for querying the adjacent post.
		*
		* @type mixed $post Optional. Post object or ID to find adjacent post for.
		* @type bool $previous Optional. Whether to retrieve previous post.
		* @type string $taxonomy Optional. Taxonomy, if $in_same_term is true. Default 'category'.
		* @type bool $in_same_term Optional. Whether post should be in a same taxonomy term.
		* @type array $excluded_terms Optional. Array of excluded term IDs.
		* }
		* @return mixed Post object on success. False if no adjacent post exists. Null on failure.
		*/
		protected function get_post( $args ) {
		$this->current_post = get_post( $args['post'] );
		$this->excluded_terms = array_map( 'intval', $args['excluded_terms'] );
		$this->adjacent = $args['previous'] ? 'previous' : 'next';
		$this->in_same_term = (bool) $args['in_same_term'];

		if ( ! empty( $term_array ) ) {
		$excluded_terms = array_diff( $excluded_terms, $term_array );
		$posts_in_ex_terms_sql = '';
		// Return null when either the post or taxonomy doesn't exist.
		if ( ! $this->current_post ) {
		return;
		}
		if ( $this->in_same_term \|\| $this->excluded_terms ) {
		if ( ! taxonomy_exists( $args['taxonomy'] ) ) {
		return;
		}
		}

		if ( ! empty( $excluded_terms ) ) {
		$posts_in_ex_terms_sql = $wpdb->prepare( " AND tt.taxonomy = %s AND tt.term_id NOT IN (" . implode( $excluded_terms, ',' ) . ')', $taxonomy );
		// Build our arguments for WP_Query.
		$query_args = array(
		'posts_per_page' => 1,
		'post_status' => 'publish',
		'post_type' => 'post',
		'orderby' => 'date',
		'order' => 'previous' === $this->adjacent ? 'DESC' : 'ASC',
		'no_found_rows' => true,
		'cache_results' => true,
		'date_query' => array(),
		);

		$tax_query = array();

		// Set up for requests limited to posts that share terms.
		if ( $this->in_same_term ) {
		$terms = get_the_terms( $this->current_post->ID, $args['taxonomy'] );

		if ( is_array( $terms ) && ! empty( $terms ) ) {
		$terms = wp_list_pluck( $terms, 'term_id' );
		$terms = array_values( $terms );
		$terms = array_map( 'intval', $terms );
		} else {
		unset( $terms );
		}
		}

		// Handle excluded terms.
		if ( $this->excluded_terms ) {
		$tax_query[] = array(
		'taxonomy' => $args['taxonomy'],
		'slugs' => $this->excluded_terms,
		'compare' => 'NOT IN',
		);
		}

		$adjacent = $previous ? 'previous' : 'next';
		$op = $previous ? '<' : '>';
		$order = $previous ? 'DESC' : 'ASC';

		$join = apply_filters( "get_{$adjacent}_post_join", $join, $in_same_term, $excluded_terms );
		$where = apply_filters( "get_{$adjacent}_post_where", $wpdb->prepare( "WHERE p.post_date $op %s AND p.post_type = %s AND p.post_status = 'publish' $posts_in_ex_terms_sql", $current_post_date, $post->post_type), $in_same_term, $excluded_terms );
		$sort = apply_filters( "get_{$adjacent}_post_sort", "ORDER BY p.post_date $order LIMIT 1" );

		$query = "SELECT p.ID FROM $wpdb->posts AS p $join $where $sort";
		$query_key = 'adjacent_post_' . md5( $query );
		$result = wp_cache_get( $query_key, 'counts' );
		if ( false !== $result ) {
		if ( $result )
		$result = get_post( $result );
		return $result;
		// If requesting same term, ensure excluded terms don't appear in term list.
		if ( isset( $terms ) ) {
		if ( isset( $this->excluded_terms ) && is_array( $this->excluded_terms ) ) {
		$terms = array_diff( $terms, $this->excluded_terms );
		}

		if ( ! empty( $terms ) ) {
		$tax_query[] = array(
		'taxonomy' => $args['taxonomy'],
		'terms' => $terms,
		);
		}
		}

		$result = $wpdb->get_var( $query );
		if ( null === $result )
		$result = '';
		// If we have a tax query, add it to our query args.
		if ( $tax_query ) {
		$query_args['tax_query'] = $tax_query;
		}

		// And now, the date constraint.
		$date_query_key = 'previous' === $this->adjacent ? 'before' : 'after';

		wp_cache_set( $query_key, $result, 'counts' );
		$query_args['date_query'][] = array(
		$date_query_key => $this->current_post->post_date,
		'inclusive' => true,
		);

		if ( $result )
		$result = get_post( $result );
		// Ensure the current post isn't returned, since we're using an inclusive date query.
		$query_args['post__not_in'] = array( $this->current_post->ID );

		return $result;
		/**
		* Filter the arguments passed to WP_Query when finding an adjacent post.
		*
		* @since 3.9.0
		*
		* @param array $query_args WP_Query arguments.
		* @param array $args Arguments passed to WP_Get_Adjacent_Post.
		*/
		$query_args = apply_filters( 'get_adjacent_post_query_args', $query_args, $args );

		add_filter( 'posts_clauses', array( $this, 'filter' ) );
		$query = new WP_Query( $query_args );

		if ( $query->posts ) {
		$this->adjacent_post = $query->post;
		} else {
		$this->adjacent_post = false;
		}
		}

		/**
		* Apply the deprecated filters to WP_Query's clauses.
		*
		* @param array $clauses
		* @uses $this->filter_join_and_where()
		* @uses $this->filter_sort()
		* @filter post_clauses
		* @return array
		*/
		public function filter( $clauses ) {
		// Immediately deregister these legacy filters to avoid modifying
		// any calls to WP_Query from filter callbacks hooked to WP_Query filters.
		remove_filter( 'posts_clauses', array( $this, 'filter' ) );

		// The `join` and `where` filters are identical in their parameters,
		// so we can use the same approach for both.
		foreach ( array( 'join', 'where' ) as $clause ) {
		if ( has_filter( 'get_' . $this->adjacent . '_post_' . $clause ) ) {
		$clauses[ $clause ] = $this->filter_join_and_where( $clauses[ $clause ], $clause );
		}
		}

		// The legacy `sort` filter combined the ORDER BY and LIMIT clauses,
		// while `WP_Query` does not, which requires special handling.
		if ( has_filter( 'get_' . $this->adjacent . '_post_sort' ) ) {
		$sort_clauses = $this->filter_sort( $clauses['orderby'], $clauses['limits'] );
		$clauses = array_merge( $clauses, $sort_clauses );
		}

		return $clauses;
		}

		/**
		* Apply the deprecated `join` or `where` clause filter to the clauses built by WP_Query.
		*
		* @param string $value
		* @param string $clause
		* @return string
		*/
		protected function filter_join_and_where( $value, $clause ) {
		/**
		* @deprecated 3.9.0
		*/
		return apply_filters( 'get_' . $this->adjacent . '_post_' . $clause, $value, $this->in_same_term, $this->excluded_terms );
		}

		/**
		* Apply deprecated `sort` filter, which applies to both the ORDER BY and LIMIT clauses.
		*
		* @param string $orderby
		* @param string $limits
		* @return array
		*/
		protected function filter_sort( $orderby, $limits ) {
		/**
		* @deprecated 3.9.0
		*/
		$sort = apply_filters( 'get_' . $this->adjacent . '_post_sort', 'ORDER BY ' . $orderby . ' ' . $limits );

		if ( empty( $sort ) ) {
		return compact( 'orderby', 'limits' );
		}

		// The legacy filter could allow either clause to be removed, or their order inverted, so we need to know what we have and where.
		$has_order_by = stripos( $sort, 'order by' );
		$has_limit = stripos( $sort, 'limit' );

		// Split the string of one or two clauses into their respective array keys
		if ( false !== $has_order_by && false !== $has_limit ) {
		// The LIMIT clause cannot appear before the ORDER BY clause in a valid query
		// However, since the legacy filter would allow a user to invert the order, we maintain that handling so the same errors are triggered.
		if ( $has_order_by < $has_limit ) {
		$orderby = trim( str_ireplace( 'order by', '', substr( $sort, 0, $has_limit ) ) );
		$limits = trim( substr( $sort, $has_limit ) );
		} else {
		$orderby = trim( str_ireplace( 'order by', '', substr( $sort, $has_order_by ) ) );
		$limits = trim( substr( $sort, 0, $has_order_by ) );
		}
		} elseif ( false !== $has_order_by ) {
		$orderby = trim( str_ireplace( 'order by', '', $sort ) );
		$limits = '';
		} elseif ( false !== $has_limit ) {
		$orderby = '';
		$limits = trim( $sort );
		}

		return compact( 'orderby', 'limits' );
		}
		}

		/**