HTML Examples/WP.iso/wordpress/wp-includes/class-wp-tax-query.php

PHP Script | 2017-10-02 | 18.7 KB | 650 lines

<?php
/**
 * Taxonomy API: WP_Tax_Query class
 *
 * @package WordPress
 * @subpackage Taxonomy
 * @since 4.4.0
 */

/**
 * Core class used to implement taxonomy queries for the Taxonomy API.
 *
 * Used for generating SQL clauses that filter a primary query according to object
 * taxonomy terms.
 *
 * WP_Tax_Query is a helper that allows primary query classes, such as WP_Query, to filter
 * their results by object metadata, by generating `JOIN` and `WHERE` subclauses to be
 * attached to the primary SQL query string.
 *
 * @since 3.1.0
 */
class WP_Tax_Query {

    /**
     * Array of taxonomy queries.
     *
     * See WP_Tax_Query::__construct() for information on tax query arguments.
     *
     * @since 3.1.0
     * @var array
     */
    public $queries = array();

    /**
     * The relation between the queries. Can be one of 'AND' or 'OR'.
     *
     * @since 3.1.0
     * @var string
     */
    public $relation;

    /**
     * Standard response when the query should not return any rows.
     *
     * @since 3.2.0
     *
     * @static
     * @var string
     */
    private static $no_results = array( 'join' => array( '' ), 'where' => array( '0 = 1' ) );

    /**
     * A flat list of table aliases used in the JOIN clauses.
     *
     * @since 4.1.0
     * @var array
     */
    protected $table_aliases = array();

    /**
     * Terms and taxonomies fetched by this query.
     *
     * We store this data in a flat array because they are referenced in a
     * number of places by WP_Query.
     *
     * @since 4.1.0
     * @var array
     */
    public $queried_terms = array();

    /**
     * Database table that where the metadata's objects are stored (eg $wpdb->users).
     *
     * @since 4.1.0
     * @var string
     */
    public $primary_table;

    /**
     * Column in 'primary_table' that represents the ID of the object.
     *
     * @since 4.1.0
     * @var string
     */
    public $primary_id_column;

    /**
     * Constructor.
     *
     * @since 3.1.0
     * @since 4.1.0 Added support for `$operator` 'NOT EXISTS' and 'EXISTS' values.
     *
     * @param array $tax_query {
     *     Array of taxonomy query clauses.
     *
     *     @type string $relation Optional. The MySQL keyword used to join
     *                            the clauses of the query. Accepts 'AND', or 'OR'. Default 'AND'.
     *     @type array {
     *         Optional. An array of first-order clause parameters, or another fully-formed tax query.
     *
     *         @type string           $taxonomy         Taxonomy being queried. Optional when field=term_taxonomy_id.
     *         @type string|int|array $terms            Term or terms to filter by.
     *         @type string           $field            Field to match $terms against. Accepts 'term_id', 'slug',
     *                                                 'name', or 'term_taxonomy_id'. Default: 'term_id'.
     *         @type string           $operator         MySQL operator to be used with $terms in the WHERE clause.
     *                                                  Accepts 'AND', 'IN', 'NOT IN', 'EXISTS', 'NOT EXISTS'.
     *                                                  Default: 'IN'.
     *         @type bool             $include_children Optional. Whether to include child terms.
     *                                                  Requires a $taxonomy. Default: true.
     *     }
     * }
     */
    public function __construct( $tax_query ) {
        if ( isset( $tax_query['relation'] ) ) {
            $this->relation = $this->sanitize_relation( $tax_query['relation'] );
        } else {
            $this->relation = 'AND';
        }

        $this->queries = $this->sanitize_query( $tax_query );
    }

    /**
     * Ensure the 'tax_query' argument passed to the class constructor is well-formed.
     *
     * Ensures that each query-level clause has a 'relation' key, and that
     * each first-order clause contains all the necessary keys from `$defaults`.
     *
     * @since 4.1.0
     *
     * @param array $queries Array of queries clauses.
     * @return array Sanitized array of query clauses.
     */
    public function sanitize_query( $queries ) {
        $cleaned_query = array();

        $defaults = array(
            'taxonomy' => '',
            'terms' => array(),
            'field' => 'term_id',
            'operator' => 'IN',
            'include_children' => true,
        );

        foreach ( $queries as $key => $query ) {
            if ( 'relation' === $key ) {
                $cleaned_query['relation'] = $this->sanitize_relation( $query );

            // First-order clause.
            } elseif ( self::is_first_order_clause( $query ) ) {

                $cleaned_clause = array_merge( $defaults, $query );
                $cleaned_clause['terms'] = (array) $cleaned_clause['terms'];
                $cleaned_query[] = $cleaned_clause;

                /*
                 * Keep a copy of the clause in the flate
                 * $queried_terms array, for use in WP_Query.
                 */
                if ( ! empty( $cleaned_clause['taxonomy'] ) && 'NOT IN' !== $cleaned_clause['operator'] ) {
                    $taxonomy = $cleaned_clause['taxonomy'];
                    if ( ! isset( $this->queried_terms[ $taxonomy ] ) ) {
                        $this->queried_terms[ $taxonomy ] = array();
                    }

                    /*
                     * Backward compatibility: Only store the first
                     * 'terms' and 'field' found for a given taxonomy.
                     */
                    if ( ! empty( $cleaned_clause['terms'] ) && ! isset( $this->queried_terms[ $taxonomy ]['terms'] ) ) {
                        $this->queried_terms[ $taxonomy ]['terms'] = $cleaned_clause['terms'];
                    }

                    if ( ! empty( $cleaned_clause['field'] ) && ! isset( $this->queried_terms[ $taxonomy ]['field'] ) ) {
                        $this->queried_terms[ $taxonomy ]['field'] = $cleaned_clause['field'];
                    }
                }

            // Otherwise, it's a nested query, so we recurse.
            } elseif ( is_array( $query ) ) {
                $cleaned_subquery = $this->sanitize_query( $query );

                if ( ! empty( $cleaned_subquery ) ) {
                    // All queries with children must have a relation.
                    if ( ! isset( $cleaned_subquery['relation'] ) ) {
                        $cleaned_subquery['relation'] = 'AND';
                    }

                    $cleaned_query[] = $cleaned_subquery;
                }
            }
        }

        return $cleaned_query;
    }

    /**
     * Sanitize a 'relation' operator.
     *
     * @since 4.1.0
     *
     * @param string $relation Raw relation key from the query argument.
     * @return string Sanitized relation ('AND' or 'OR').
     */
    public function sanitize_relation( $relation ) {
        if ( 'OR' === strtoupper( $relation ) ) {
            return 'OR';
        } else {
            return 'AND';
        }
    }

    /**
     * Determine whether a clause is first-order.
     *
     * A "first-order" clause is one that contains any of the first-order
     * clause keys ('terms', 'taxonomy', 'include_children', 'field',
     * 'operator'). An empty clause also counts as a first-order clause,
     * for backward compatibility. Any clause that doesn't meet this is
     * determined, by process of elimination, to be a higher-order query.
     *
     * @since 4.1.0
     *
     * @static
     *
     * @param array $query Tax query arguments.
     * @return bool Whether the query clause is a first-order clause.
     */
    protected static function is_first_order_clause( $query ) {
        return is_array( $query ) && ( empty( $query ) || array_key_exists( 'terms', $query ) || array_key_exists( 'taxonomy', $query ) || array_key_exists( 'include_children', $query ) || array_key_exists( 'field', $query ) || array_key_exists( 'operator', $query ) );
    }

    /**
     * Generates SQL clauses to be appended to a main query.
     *
     * @since 3.1.0
     *
     * @static
     *
     * @param string $primary_table     Database table where the object being filtered is stored (eg wp_users).
     * @param string $primary_id_column ID column for the filtered object in $primary_table.
     * @return array {
     *     Array containing JOIN and WHERE SQL clauses to append to the main query.
     *
     *     @type string $join  SQL fragment to append to the main JOIN clause.
     *     @type string $where SQL fragment to append to the main WHERE clause.
     * }
     */
    public function get_sql( $primary_table, $primary_id_column ) {
        $this->primary_table = $primary_table;
        $this->primary_id_column = $primary_id_column;

        return $this->get_sql_clauses();
    }

    /**
     * Generate SQL clauses to be appended to a main query.
     *
     * Called by the public WP_Tax_Query::get_sql(), this method
     * is abstracted out to maintain parity with the other Query classes.
     *
     * @since 4.1.0
     *
     * @return array {
     *     Array containing JOIN and WHERE SQL clauses to append to the main query.
     *
     *     @type string $join  SQL fragment to append to the main JOIN clause.
     *     @type string $where SQL fragment to append to the main WHERE clause.
     * }
     */
    protected function get_sql_clauses() {
        /*
         * $queries are passed by reference to get_sql_for_query() for recursion.
         * To keep $this->queries unaltered, pass a copy.
         */
        $queries = $this->queries;
        $sql = $this->get_sql_for_query( $queries );

        if ( ! empty( $sql['where'] ) ) {
            $sql['where'] = ' AND ' . $sql['where'];
        }

        return $sql;
    }

    /**
     * Generate SQL clauses for a single query array.
     *
     * If nested subqueries are found, this method recurses the tree to
     * produce the properly nested SQL.
     *
     * @since 4.1.0
     *
     * @param array $query Query to parse (passed by reference).
     * @param int   $depth Optional. Number of tree levels deep we currently are.
     *                     Used to calculate indentation. Default 0.
     * @return array {
     *     Array containing JOIN and WHERE SQL clauses to append to a single query array.
     *
     *     @type string $join  SQL fragment to append to the main JOIN clause.
     *     @type string $where SQL fragment to append to the main WHERE clause.
     * }
     */
    protected function get_sql_for_query( &$query, $depth = 0 ) {
        $sql_chunks = array(
            'join'  => array(),
            'where' => array(),
        );

        $sql = array(
            'join'  => '',
            'where' => '',
        );

        $indent = '';
        for ( $i = 0; $i < $depth; $i++ ) {
            $indent .= "  ";
        }

        foreach ( $query as $key => &$clause ) {
            if ( 'relation' === $key ) {
                $relation = $query['relation'];
            } elseif ( is_array( $clause ) ) {

                // This is a first-order clause.
                if ( $this->is_first_order_clause( $clause ) ) {
                    $clause_sql = $this->get_sql_for_clause( $clause, $query );

                    $where_count = count( $clause_sql['where'] );
                    if ( ! $where_count ) {
                        $sql_chunks['where'][] = '';
                    } elseif ( 1 === $where_count ) {
                        $sql_chunks['where'][] = $clause_sql['where'][0];
                    } else {
                        $sql_chunks['where'][] = '( ' . implode( ' AND ', $clause_sql['where'] ) . ' )';
                    }

                    $sql_chunks['join'] = array_merge( $sql_chunks['join'], $clause_sql['join'] );
                // This is a subquery, so we recurse.
                } else {
                    $clause_sql = $this->get_sql_for_query( $clause, $depth + 1 );

                    $sql_chunks['where'][] = $clause_sql['where'];
                    $sql_chunks['join'][]  = $clause_sql['join'];
                }
            }
        }

        // Filter to remove empties.
        $sql_chunks['join']  = array_filter( $sql_chunks['join'] );
        $sql_chunks['where'] = array_filter( $sql_chunks['where'] );

        if ( empty( $relation ) ) {
            $relation = 'AND';
        }

        // Filter duplicate JOIN clauses and combine into a single string.
        if ( ! empty( $sql_chunks['join'] ) ) {
            $sql['join'] = implode( ' ', array_unique( $sql_chunks['join'] ) );
        }

        // Generate a single WHERE clause with proper brackets and indentation.
        if ( ! empty( $sql_chunks['where'] ) ) {
            $sql['where'] = '( ' . "\n  " . $indent . implode( ' ' . "\n  " . $indent . $relation . ' ' . "\n  " . $indent, $sql_chunks['where'] ) . "\n" . $indent . ')';
        }

        return $sql;
    }

    /**
     * Generate SQL JOIN and WHERE clauses for a "first-order" query clause.
     *
     * @since 4.1.0
     *
     * @global wpdb $wpdb The WordPress database abstraction object.
     *
     * @param array $clause       Query clause (passed by reference).
     * @param array $parent_query Parent query array.
     * @return array {
     *     Array containing JOIN and WHERE SQL clauses to append to a first-order query.
     *
     *     @type string $join  SQL fragment to append to the main JOIN clause.
     *     @type string $where SQL fragment to append to the main WHERE clause.
     * }
     */
    public function get_sql_for_clause( &$clause, $parent_query ) {
        global $wpdb;

        $sql = array(
            'where' => array(),
            'join'  => array(),
        );

        $join = $where = '';

        $this->clean_query( $clause );

        if ( is_wp_error( $clause ) ) {
            return self::$no_results;
        }

        $terms = $clause['terms'];
        $operator = strtoupper( $clause['operator'] );

        if ( 'IN' == $operator ) {

            if ( empty( $terms ) ) {
                return self::$no_results;
            }

            $terms = implode( ',', $terms );

            /*
             * Before creating another table join, see if this clause has a
             * sibling with an existing join that can be shared.
             */
            $alias = $this->find_compatible_table_alias( $clause, $parent_query );
            if ( false === $alias ) {
                $i = count( $this->table_aliases );
                $alias = $i ? 'tt' . $i : $wpdb->term_relationships;

                // Store the alias as part of a flat array to build future iterators.
                $this->table_aliases[] = $alias;

                // Store the alias with this clause, so later siblings can use it.
                $clause['alias'] = $alias;

                $join .= " LEFT JOIN $wpdb->term_relationships";
                $join .= $i ? " AS $alias" : '';
                $join .= " ON ($this->primary_table.$this->primary_id_column = $alias.object_id)";
            }


            $where = "$alias.term_taxonomy_id $operator ($terms)";

        } elseif ( 'NOT IN' == $operator ) {

            if ( empty( $terms ) ) {
                return $sql;
            }

            $terms = implode( ',', $terms );

            $where = "$this->primary_table.$this->primary_id_column NOT IN (
                SELECT object_id
                FROM $wpdb->term_relationships
                WHERE term_taxonomy_id IN ($terms)
            )";

        } elseif ( 'AND' == $operator ) {

            if ( empty( $terms ) ) {
                return $sql;
            }

            $num_terms = count( $terms );

            $terms = implode( ',', $terms );

            $where = "(
                SELECT COUNT(1)
                FROM $wpdb->term_relationships
                WHERE term_taxonomy_id IN ($terms)
                AND object_id = $this->primary_table.$this->primary_id_column
            ) = $num_terms";

        } elseif ( 'NOT EXISTS' === $operator || 'EXISTS' === $operator ) {

            $where = $wpdb->prepare( "$operator (
                SELECT 1
                FROM $wpdb->term_relationships
                INNER JOIN $wpdb->term_taxonomy
                ON $wpdb->term_taxonomy.term_taxonomy_id = $wpdb->term_relationships.term_taxonomy_id
                WHERE $wpdb->term_taxonomy.taxonomy = %s
                AND $wpdb->term_relationships.object_id = $this->primary_table.$this->primary_id_column
            )", $clause['taxonomy'] );

        }

        $sql['join'][]  = $join;
        $sql['where'][] = $where;
        return $sql;
    }

    /**
     * Identify an existing table alias that is compatible with the current query clause.
     *
     * We avoid unnecessary table joins by allowing each clause to look for
     * an existing table alias that is compatible with the query that it
     * needs to perform.
     *
     * An existing alias is compatible if (a) it is a sibling of `$clause`
     * (ie, it's under the scope of the same relation), and (b) the combination
     * of operator and relation between the clauses allows for a shared table
     * join. In the case of WP_Tax_Query, this only applies to 'IN'
     * clauses that are connected by the relation 'OR'.
     *
     * @since 4.1.0
     *
     * @param array       $clause       Query clause.
     * @param array       $parent_query Parent query of $clause.
     * @return string|false Table alias if found, otherwise false.
     */
    protected function find_compatible_table_alias( $clause, $parent_query ) {
        $alias = false;

        // Sanity check. Only IN queries use the JOIN syntax .
        if ( ! isset( $clause['operator'] ) || 'IN' !== $clause['operator'] ) {
            return $alias;
        }

        // Since we're only checking IN queries, we're only concerned with OR relations.
        if ( ! isset( $parent_query['relation'] ) || 'OR' !== $parent_query['relation'] ) {
            return $alias;
        }

        $compatible_operators = array( 'IN' );

        foreach ( $parent_query as $sibling ) {
            if ( ! is_array( $sibling ) || ! $this->is_first_order_clause( $sibling ) ) {
                continue;
            }

            if ( empty( $sibling['alias'] ) || empty( $sibling['operator'] ) ) {
                continue;
            }

            // The sibling must both have compatible operator to share its alias.
            if ( in_array( strtoupper( $sibling['operator'] ), $compatible_operators ) ) {
                $alias = $sibling['alias'];
                break;
            }
        }

        return $alias;
    }

    /**
     * Validates a single query.
     *
     * @since 3.2.0
     *
     * @param array $query The single query. Passed by reference.
     */
    private function clean_query( &$query ) {
        if ( empty( $query['taxonomy'] ) ) {
            if ( 'term_taxonomy_id' !== $query['field'] ) {
                $query = new WP_Error( 'invalid_taxonomy', __( 'Invalid taxonomy.' ) );
                return;
            }

            // so long as there are shared terms, include_children requires that a taxonomy is set
            $query['include_children'] = false;
        } elseif ( ! taxonomy_exists( $query['taxonomy'] ) ) {
            $query = new WP_Error( 'invalid_taxonomy', __( 'Invalid taxonomy.' ) );
            return;
        }

        $query['terms'] = array_unique( (array) $query['terms'] );

        if ( is_taxonomy_hierarchical( $query['taxonomy'] ) && $query['include_children'] ) {
            $this->transform_query( $query, 'term_id' );

            if ( is_wp_error( $query ) )
                return;

            $children = array();
            foreach ( $query['terms'] as $term ) {
                $children = array_merge( $children, get_term_children( $term, $query['taxonomy'] ) );
                $children[] = $term;
            }
            $query['terms'] = $children;
        }

        $this->transform_query( $query, 'term_taxonomy_id' );
    }

    /**
     * Transforms a single query, from one field to another.
     *
     * Operates on the `$query` object by reference. In the case of error,
     * `$query` is converted to a WP_Error object.
     *
     * @since 3.2.0
     *
     * @global wpdb $wpdb The WordPress database abstraction object.
     *
     * @param array  $query           The single query. Passed by reference.
     * @param string $resulting_field The resulting field. Accepts 'slug', 'name', 'term_taxonomy_id',
     *                                or 'term_id'. Default 'term_id'.
     */
    public function transform_query( &$query, $resulting_field ) {
        if ( empty( $query['terms'] ) )
            return;

        if ( $query['field'] == $resulting_field )
            return;

        $resulting_field = sanitize_key( $resulting_field );

        // Empty 'terms' always results in a null transformation.
        $terms = array_filter( $query['terms'] );
        if ( empty( $terms ) ) {
            $query['terms'] = array();
            $query['field'] = $resulting_field;
            return;
        }

        $args = array(
            'get'                    => 'all',
            'number'                 => 0,
            'taxonomy'               => $query['taxonomy'],
            'update_term_meta_cache' => false,
            'orderby'                => 'none',
        );

        // Term query parameter name depends on the 'field' being searched on.
        switch ( $query['field'] ) {
            case 'slug':
                $args['slug'] = $terms;
                break;
            case 'name':
                $args['name'] = $terms;
                break;
            case 'term_taxonomy_id':
                $args['term_taxonomy_id'] = $terms;
                break;
            default:
                $args['include'] = wp_parse_id_list( $terms );
                break;
        }

        $term_query = new WP_Term_Query();
        $term_list  = $term_query->query( $args );

        if ( is_wp_error( $term_list ) ) {
            $query = $term_list;
            return;
        }

        if ( 'AND' == $query['operator'] && count( $term_list ) < count( $query['terms'] ) ) {
            $query = new WP_Error( 'inexistent_terms', __( 'Inexistent terms.' ) );
            return;
        }

        $query['terms'] = wp_list_pluck( $term_list, $resulting_field );
        $query['field'] = $resulting_field;
    }
}