[2.0] Minor change in *Walker to be able to be used by custom assigned Walkers

lib/Doctrine/ORM/Query/Parser.php

@@ -257,7 +257,8 @@ class Parser
         }
 
         // Create TreeWalker who creates the SQL from the AST
-        $treeWalker = $this->_treeWalker ?: new SqlWalker(
+        $treeWalker = $this->_treeWalker ?: new SqlWalker();
+        $treeWalker->init(
             $this->_query, $this->_parserResult, $this->_queryComponents
         );
 

lib/Doctrine/ORM/Query/SqlWalker.php

@@ -72,12 +72,9 @@ class SqlWalker implements TreeWalker
     private $_useSqlTableAliases = true;
 
     /**
-     * Initializes a new SqlWalker instance with the given Query and ParserResult.
-     *
-     * @param Query $query The parsed Query.
-     * @param ParserResult $parserResult The result of the parsing process.
+     * @inheritdoc
      */
-    public function __construct($query, $parserResult, array $queryComponents)
+    public function init($query, $parserResult, array $queryComponents)
     {
         $this->_rsm = $parserResult->getResultSetMapping();
         $this->_query = $query;

lib/Doctrine/ORM/Query/TreeWalker.php

@@ -29,6 +29,15 @@ namespace Doctrine\ORM\Query;
  */
 interface TreeWalker
 {
+    /**
+     * Initializes TreeWalker with important information about the ASTs to be walked
+     *
+     * @param Query $query The parsed Query.
+     * @param ParserResult $parserResult The result of the parsing process.
+     * @param array $queryComponents Query components (symbol table)
+     */
+    function init($query, $parserResult, array $queryComponents);
+    
     /**
      * Walks down a SelectStatement AST node, thereby generating the appropriate SQL.
      *

lib/Doctrine/ORM/Query/TreeWalkerAdapter.php

@@ -30,6 +30,11 @@ namespace Doctrine\ORM\Query;
  */
 abstract class TreeWalkerAdapter implements TreeWalker
 {
+    /**
+     * @inheritdoc
+     */
+    public function init($query, $parserResult, array $queryComponents) {}
+    
     /**
      * Walks down a SelectStatement AST node, thereby generating the appropriate SQL.
      *