Ticket #26937: 26937.5.patch

src/wp-includes/link-template.php

@@ -1125 +1125 @@
  * @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.
+ * @param mixed        $current_post   Optional. Post object, array, or ID to find adjacent post for.
+ * @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;
+function get_adjacent_post( $in_same_term = false, $excluded_terms = '', $previous = true, $taxonomy = 'category', $current_post = false ) {
+        if ( ! $current_post ) {
+                $current_post = get_post();
+        }
 
-        if ( ( ! $post = get_post() ) || ! taxonomy_exists( $taxonomy ) )
-                return null;
+        $adjacent = new WP_Get_Adjacent_Post( $current_post, $previous, $in_same_term, $taxonomy, $excluded_terms );
+        return $adjacent->adjacent_post;
+}
 
-        $current_post_date = $post->post_date;
+/**
+ * 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;
 
-        $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";
+        private $current_post   = false;
+        private $adjacent       = 'previous';
+        private $taxonomy       = 'category';
+        private $in_same_term   = false;
+        private $excluded_terms = '';
 
-                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 );
+        /**
+         * Validate inputs, set up class variables, and determine adjacent post
+         *
+         * @param mixed        $current_post   Optional. Post object, array, or ID to find adjacent post for.
+         * @param bool         $previous       Optional. Whether to retrieve previous post.
+         * @param bool         $in_same_term   Optional. Whether post should be in a same taxonomy term.
+         * @param string       $taxonomy       Optional. Taxonomy, if $in_same_term is true. Default 'category'.
+         * @param array|string $excluded_terms Optional. Array or comma-separated list of excluded term IDs.
+         * @return null
+         */
+        public function __construct( $current_post = false, $previous = true, $in_same_term = false, $taxonomy = 'category', $excluded_terms = '' ) {
+                // Validate specified post, otherwise default to current post
+                if ( is_a( $current_post, 'WP_Post' ) ) {
+                        $this->current_post = $current_post;
+                } elseif ( is_array( $current_post ) && isset( $current_post['ID'] ) ) {
+                        $this->current_post = get_post( $current_post['ID'] );
+                } elseif ( is_numeric( $current_post ) ) {
+                        $this->current_post = get_post( (int) $current_post );
+                } else {
+                        $this->current_post = get_post();
                 }
 
-                $posts_in_ex_terms_sql = $wpdb->prepare( "AND tt.taxonomy = %s", $taxonomy );
+                // Validate terms specified for exclusion
                 if ( ! empty( $excluded_terms ) ) {
                         if ( ! is_array( $excluded_terms ) ) {
-                                // back-compat, $excluded_terms used to be $excluded_terms with IDs separated by " and "
+                                // back-compat, $excluded_terms used to be 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 );
@@ -1161 +1186 @@
                                 }
                         }
 
-                        $excluded_terms = array_map( 'intval', $excluded_terms );
+                        $this->excluded_terms = array_map( 'intval', $excluded_terms );
+                }
 
-                        if ( ! empty( $term_array ) ) {
-                                $excluded_terms = array_diff( $excluded_terms, $term_array );
-                                $posts_in_ex_terms_sql = '';
+                // Validate remaining inputs
+                $this->adjacent       = $previous ? 'previous' : 'next';
+                $this->in_same_term   = (bool) $in_same_term;
+                $this->taxonomy       = taxonomy_exists( $taxonomy ) ? $taxonomy : '';
+
+                // Determine adjacent post
+                $this->get_post();
+        }
+
+        /**
+         * 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 {
+                        return null;
+                }
+        }
+
+        /**
+         * Determine adjacent post for specified post and adjacency
+         *
+         * @return mixed Post object if successful. Null if current post doesn't exist. Empty string if no corresponding adjacent post exists.
+         */
+        protected function get_post() {
+                // Return null when either the post or taxonomy doesn't exist
+                if ( ! $this->current_post || ! taxonomy_exists( $this->taxonomy ) ) {
+                        return;
+                }
+
+                // Query basics
+                $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,
+                        'suppress_filters' => false,
+                        'date_query'       => array(),
+                );
+
+                // Query pieces
+                $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, $this->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 );
                         }
+                }
 
-                        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 );
+                // Handle excluded terms
+                if ( ! empty( $this->excluded_terms ) ) {
+                        $tax_query[] = array(
+                                'taxonomy' => $this->taxonomy,
+                                'slugs'    => $this->excluded_terms,
+                                'compare'  => 'NOT IN',
+                        );
+                }
+
+                // If requesting same term, ensure that excluded terms don't appear in term list 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' => $this->taxonomy,
+                                        'terms'    => $terms,
+                                );
+                        }
                 }
+
+                // If we have a tax query, add it to our query args
+                if ( ! empty( $tax_query ) ) {
+                        $args['tax_query'] = $tax_query;
+                }
+
+                // And now, the date constraint
+                if ( 'previous' === $this->adjacent ) {
+                        $args['date_query'][] = array(
+                                'before'    => $this->current_post->post_date,
+                                'inclusive' => true,
+                        );
+                } else {
+                        $args['date_query'][] = array(
+                                'after'     => $this->current_post->post_date,
+                                'inclusive' => true,
+                        );
+                }
+
+                // Ensure the current post isn't returned, since we're using an inclusive date query
+                $args['post__not_in'] = array( $this->current_post->ID );
+
+                /**
+                 * Let plugins modify the parameters for the adjacent post query
+                 *
+                 * @since 3.9.0
+                 *
+                 * @param array $args WP_Query arguments
+                 * @param array       Arguments when `get_adjacent_post()` was called
+                 */
+                $args = apply_filters( 'get_adjacent_post_args', $args, compact( 'in_same_term', 'excluded_terms', 'previous', 'taxonony' ) );
+
+                // Get the posts and return either the post object or null
+                add_filter( 'posts_clauses', array( $this, 'filter' ) );
+                $results = get_posts( $args );
+
+                if ( is_array( $results ) && ! empty( $results ) ) {
+                        $this->adjacent_post = array_shift( $results );
+                } else {
+                        $this->adjacent_post = '';
+                }
         }
 
-        $adjacent = $previous ? 'previous' : 'next';
-        $op = $previous ? '<' : '>';
-        $order = $previous ? 'DESC' : 'ASC';
+        /**
+         * Apply the legacy 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' ) );
 
-        $join  = apply_filters( "get_{$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" );
+                // 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 );
+                        }
+                }
 
-        $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;
+                // 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;
         }
 
-        $result = $wpdb->get_var( $query );
-        if ( null === $result )
-                $result = '';
+        /**
+         * Apply the legacy `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 ) {
+                return apply_filters( 'get_' . $this->adjacent . '_post_' . $clause, $value, $this->in_same_term, $this->excluded_terms );
+        }
 
-        wp_cache_set( $query_key, $result, 'counts' );
+        /**
+         * Apply legacy `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 ) {
+                $sort = apply_filters( 'get_' . $this->adjacent . '_post_sort', 'ORDER BY ' . $orderby . ' ' . $limits );
 
-        if ( $result )
-                $result = get_post( $result );
+                if ( empty( $sort ) ) {
+                        return compact( 'orderby', 'limits' );
+                }
 
-        return $result;
+                // 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' );
+        }
 }
 
 /**

tests/phpunit/tests/link.php

@@ -167 +167 @@
                 $this->assertEquals( array( $post_two ), get_boundary_post( true, '', true, 'post_tag' ) );
                 $this->assertEquals( array( $post_four ), get_boundary_post( true, '', false, 'post_tag' ) );
         }
+
+        /**
+         * @ticket 26937
+         */
+        function test_legacy_get_adjacent_post_filters() {
+                // Need some sample posts to test adjacency
+                $post_one = $this->factory->post->create_and_get( array(
+                        'post_title' => 'First',
+                        'post_date' => '2012-01-01 12:00:00'
+                ) );
+
+                $post_two = $this->factory->post->create_and_get( array(
+                        'post_title' => 'Second',
+                        'post_date' => '2012-02-01 12:00:00'
+                ) );
+
+                $post_three = $this->factory->post->create_and_get( array(
+                        'post_title' => 'Third',
+                        'post_date' => '2012-03-01 12:00:00'
+                ) );
+
+                $post_four = $this->factory->post->create_and_get( array(
+                        'post_title' => 'Fourth',
+                        'post_date' => '2012-04-01 12:00:00'
+                ) );
+
+                // Add some meta so we can join the postmeta table and query
+                add_post_meta( $post_three->ID, 'unit_test_meta', 'waffle' );
+
+                // Test "where" filter for a previous post
+                add_filter( 'get_previous_post_where', array( $this, 'filter_previous_post_where' ) );
+                $this->go_to( get_permalink( $post_three->ID ) );
+                $this->assertEquals( $post_one, get_adjacent_post( false, null, true ) );
+                remove_filter( 'get_previous_post_where', array( $this, 'filter_previous_post_where' ) );
+
+                // Test "where" filter for a next post
+                add_filter( 'get_next_post_where', array( $this, 'filter_next_post_where' ) );
+                $this->go_to( get_permalink( $post_two->ID ) );
+                $this->assertEquals( $post_four, get_adjacent_post( false, null, false ) );
+                remove_filter( 'get_next_post_where', array( $this, 'filter_next_post_where' ) );
+
+                // Test "join" filter by joining the postmeta table and restricting by meta key
+                add_filter( 'get_next_post_join', array( $this, 'filter_next_post_join' ) );
+                add_filter( 'get_next_post_where', array( $this, 'filter_next_post_where_with_join' ) );
+                $this->go_to( get_permalink( $post_one->ID ) );
+                $this->assertEquals( $post_three, get_adjacent_post( false, null, false ) );
+                remove_filter( 'get_next_post_join', array( $this, 'filter_next_post_join' ) );
+                remove_filter( 'get_next_post_where', array( $this, 'filter_next_post_where_with_join' ) );
+
+                // Test "sort" filter when modifying ORDER BY clause
+                add_filter( 'get_next_post_sort', array( $this, 'filter_next_post_sort' ) );
+                $this->go_to( get_permalink( $post_one->ID ) );
+                $this->assertEquals( $post_four, get_adjacent_post( false, null, false ) );
+                remove_filter( 'get_next_post_sort', array( $this, 'filter_next_post_sort' ) );
+
+                // Test "sort" filter when modifying LIMIT clause
+                add_filter( 'get_next_post_sort', array( $this, 'filter_next_post_sort_limit' ) );
+                $this->go_to( get_permalink( $post_one->ID ) );
+                $this->assertEquals( $post_three, get_adjacent_post( false, null, false ) );
+                remove_filter( 'get_next_post_sort', array( $this, 'filter_next_post_sort_limit' ) );
+        }
+
+        /**
+         * Filter callback for `test_legacy_get_adjacent_post_filters()`
+         */
+        function filter_previous_post_where( $where ) {
+                $where .= " AND post_title !='Second'";
+                return $where;
+        }
+
+        /**
+         * Filter callback for `test_legacy_get_adjacent_post_filters()`
+         */
+        function filter_next_post_where( $where ) {
+                $where .= " AND post_title !='Third'";
+                return $where;
+        }
+
+        /**
+         * Filter callback for `test_legacy_get_adjacent_post_filters()`
+         */
+        function filter_next_post_join( $join ) {
+                global $wpdb;
+
+                $join .= " INNER JOIN {$wpdb->postmeta} ON {$wpdb->posts}.ID = {$wpdb->postmeta}.post_id";
+                return $join;
+        }
+
+        /**
+         * Filter callback for `test_legacy_get_adjacent_post_filters()`
+         */
+        function filter_next_post_where_with_join( $where ) {
+                global $wpdb;
+
+                $where .= " AND {$wpdb->postmeta}.meta_key = 'unit_test_meta'";
+                return $where;
+        }
+
+        /**
+         * Filter callback for `test_legacy_get_adjacent_post_filters()`
+         */
+        function filter_next_post_sort( $sort ) {
+                global $wpdb;
+
+                $sort = str_replace( $wpdb->posts . '.post_date', $wpdb->posts . '.post_title', $sort );
+                return $sort;
+        }
+
+        /**
+         * Filter callback for `test_legacy_get_adjacent_post_filters()`
+         */
+        function filter_next_post_sort_limit( $sort ) {
+                $sort = str_replace( 'LIMIT 0, 1', 'LIMIT 1, 2', $sort );
+                return $sort;
+        }
 }
+ No newline at end of file