Merge "Add Database::unionConditionPermutations()"

[lhc/web/wiklou.git] / includes / libs / rdbms / database / Database.php

diff --git a/includes/libs/rdbms/database/Database.php b/includes/libs/rdbms/database/Database.php
index 559c28b..723a4a6 100644 (file)
--- a/includes/libs/rdbms/database/Database.php
+++ b/includes/libs/rdbms/database/Database.php
@@ -2481,6 +2481,77 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
                return '(' . implode( $glue, $sqls ) . ')';
        }
 
+       public function unionConditionPermutations(
+               $table, $vars, array $permute_conds, $extra_conds = '', $fname = __METHOD__,
+               $options = [], $join_conds = []
+       ) {
+               // First, build the Cartesian product of $permute_conds
+               $conds = [ [] ];
+               foreach ( $permute_conds as $field => $values ) {
+                       if ( !$values ) {
+                               // Skip empty $values
+                               continue;
+                       }
+                       $values = array_unique( $values ); // For sanity
+                       $newConds = [];
+                       foreach ( $conds as $cond ) {
+                               foreach ( $values as $value ) {
+                                       $cond[$field] = $value;
+                                       $newConds[] = $cond; // Arrays are by-value, not by-reference, so this works
+                               }
+                       }
+                       $conds = $newConds;
+               }
+
+               $extra_conds = $extra_conds === '' ? [] : (array)$extra_conds;
+
+               // If there's just one condition and no subordering, hand off to
+               // selectSQLText directly.
+               if ( count( $conds ) === 1 &&
+                       ( !isset( $options['INNER ORDER BY'] ) || !$this->unionSupportsOrderAndLimit() )
+               ) {
+                       return $this->selectSQLText(
+                               $table, $vars, $conds[0] + $extra_conds, $fname, $options, $join_conds
+                       );
+               }
+
+               // Otherwise, we need to pull out the order and limit to apply after
+               // the union. Then build the SQL queries for each set of conditions in
+               // $conds. Then union them together (using UNION ALL, because the
+               // product *should* already be distinct).
+               $orderBy = $this->makeOrderBy( $options );
+               $limit = isset( $options['LIMIT'] ) ? $options['LIMIT'] : null;
+               $offset = isset( $options['OFFSET'] ) ? $options['OFFSET'] : false;
+               $all = empty( $options['NOTALL'] ) && !in_array( 'NOTALL', $options );
+               if ( !$this->unionSupportsOrderAndLimit() ) {
+                       unset( $options['ORDER BY'], $options['LIMIT'], $options['OFFSET'] );
+               } else {
+                       if ( array_key_exists( 'INNER ORDER BY', $options ) ) {
+                               $options['ORDER BY'] = $options['INNER ORDER BY'];
+                       }
+                       if ( $limit !== null && is_numeric( $offset ) && $offset != 0 ) {
+                               // We need to increase the limit by the offset rather than
+                               // using the offset directly, otherwise it'll skip incorrectly
+                               // in the subqueries.
+                               $options['LIMIT'] = $limit + $offset;
+                               unset( $options['OFFSET'] );
+                       }
+               }
+
+               $sqls = [];
+               foreach ( $conds as $cond ) {
+                       $sqls[] = $this->selectSQLText(
+                               $table, $vars, $cond + $extra_conds, $fname, $options, $join_conds
+                       );
+               }
+               $sql = $this->unionQueries( $sqls, $all ) . $orderBy;
+               if ( $limit !== null ) {
+                       $sql = $this->limitResult( $sql, $limit, $offset );
+               }
+
+               return $sql;
+       }
+
        public function conditional( $cond, $trueVal, $falseVal ) {
                if ( is_array( $cond ) ) {
                        $cond = $this->makeList( $cond, self::LIST_AND );