- Patch #16111 by chx: generalized node_rewrite_query to db_rewrite_query.

1 files changed, 92 insertions, 0 deletions

diff --git a/includes/database.inc b/includes/database.inc
index 0148f328d..e2d8057b6 100644
--- a/includes/database.inc
+++ b/includes/database.inc
@@ -169,6 +169,98 @@ function db_queryd($query) {
 }
 
 /**
+ * Helper function for db_rewrite_sql.
+ *
+ * Collects JOIN and WHERE statements via hook_sql.
+ * Decides whether to select primary_key or DISTINCT(primary_key)
+ *
+ * @param $query
+ *    query to be rewritten
+ * @param $primary_table
+ *   Name or alias of the table which has the primary key field for this query. Possible values are: comments, forum, node, taxonomy, vocabulary
+ * @param $primary_key
+ *   name of the primary key field.
+ * @param $args
+ *  array of additional args
+ * @return
+ *   An array: join statements, where statements, field or DISTINCT(field)
+ */
+function _db_rewrite_sql($query = '', $primary_table = 'n', $primary_key = 'nid', $args = array()) {
+  $where = array();
+  $join = array();
+  $distinct = FALSE;
+  foreach (module_implements('db_rewrite_sql') as $module) {
+    $result = module_invoke($module, 'db_rewrite_sql', $query, $primary_table, $primary_key, $args);
+    if (is_array($result)) {
+      if (isset($result['where'])) {
+        $where[] .= $result['where'];
+      }
+      if (isset($result['join'])) {
+        $join[] .= $result['join'];
+      }
+      if (isset($result['distinct']) && $result['distinct']) {
+        $distinct = TRUE;
+      }
+    }
+    elseif (isset($result)) {
+      $where[] .= $result;
+    }
+  }
+
+  $where = empty($where) ? '' : '('. implode(') AND (',$where).')';
+  $join = empty($join) ? '' : implode(' ',$join);
+  $field = $primary_table .'.'. $primary_key;
+
+  return array($join, $where, $distinct ? 'DISTINCT('. $field .')' : $field);
+}
+
+/**
+ * Rewrites node queries.
+ *
+ * @param $query
+ *    query to be rewritten
+ * @param $primary_table
+ *   Name or alias of the table which has the primary key field for this query. Possible values are: comments, forum, node, taxonomy, vocabulary
+ * @param $primary_key
+ *   name of the primary key field.
+ * @param $args
+ *  an array of arguments, passed to the implementations of hook_db_rewrite_sql
+ * @return
+ *   The original query with JOIN and WHERE statements inserted from hook_db_rewrite_sql implementations. nid is rewritten if needed.
+ */
+function db_rewrite_sql($query, $primary_table = 'n', $primary_key = 'nid',  $args = array()) {
+  list($join, $where, $field_to_select) = _db_rewrite_sql($query, $primary_table, $primary_key, $args);
+
+  // (?<!text) is a negative look-behind (no need to rewrite queries that already use DISTINCT).
+  $query = preg_replace('/(SELECT.*)('. $primary_table .'\.)?(?<!DISTINCT\()(?<!DISTINCT\('. $primary_table .'\.)'. $primary_key .'(.*FROM)/AUsi', '\1'. $field_to_select .'\3', $query);
+
+  $query = preg_replace('|FROM[^[:upper:]/,]+|','\0 '. $join .' ', $query);
+  if (strpos($query, 'WHERE')) {
+    $replace = 'WHERE';
+    $add = 'AND';
+  }
+  elseif (strpos($query, 'GROUP')) {
+    $replace = 'GROUP';
+    $add = 'GROUP';
+  }
+  elseif (strpos($query, 'ORDER')) {
+    $replace = 'ORDER';
+    $add = 'ORDER';
+  }
+  elseif (strpos($query, 'LIMIT')) {
+    $replace = 'LIMIT';
+    $add = 'LIMIT';
+  }
+  else {
+    $query .= ' WHERE '. $where;
+  }
+  if (isset($replace)) {
+    $query = str_replace($replace, 'WHERE  '. $where .' '. $add .' ', $query);
+  }
+  return $query;
+}
+
+/**
  * @} End of "defgroup database".
  */