[sql] Import reference version of SQLite 3.8.7.4.

third_party/sqlite/sqlite-src-3080704/src/walker.c

 /*
 ** 2008 August 16
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This file contains routines used for walking the parser tree for
 ** an SQL statement.
 */
 #include "sqliteInt.h"
 #include <stdlib.h>
 #include <string.h>
 
 
 /*
 ** Walk an expression tree.  Invoke the callback once for each node
-** of the expression, while decending.  (In other words, the callback
+** of the expression, while descending.  (In other words, the callback
 ** is invoked before visiting children.)
 **
 ** The return value from the callback should be one of the WRC_*
 ** constants to specify how to proceed with the walk.
 **
 **    WRC_Continue      Continue descending down the tree.
 **
 **    WRC_Prune         Do not descend into child nodes.  But allow
 **                      the walk to continue with sibling nodes.
 **
 **    WRC_Abort         Do no more callbacks.  Unwind the stack and
 **                      return the top-level walk call.
 **
 ** The return value from this routine is WRC_Abort to abandon the tree walk
 ** and WRC_Continue to continue.
 */
 int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
   int rc;
   if( pExpr==0 ) return WRC_Continue;
   testcase( ExprHasProperty(pExpr, EP_TokenOnly) );
   testcase( ExprHasProperty(pExpr, EP_Reduced) );
   rc = pWalker->xExprCallback(pWalker, pExpr);
   if( rc==WRC_Continue
-              && !ExprHasAnyProperty(pExpr,EP_TokenOnly) ){
+              && !ExprHasProperty(pExpr,EP_TokenOnly) ){
     if( sqlite3WalkExpr(pWalker, pExpr->pLeft) ) return WRC_Abort;
     if( sqlite3WalkExpr(pWalker, pExpr->pRight) ) return WRC_Abort;
     if( ExprHasProperty(pExpr, EP_xIsSelect) ){
       if( sqlite3WalkSelect(pWalker, pExpr->x.pSelect) ) return WRC_Abort;
     }else{
       if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
     }
   }
   return rc & WRC_Abort;
 }
@@ skipping 49 matching lines @@
         return WRC_Abort;
       }
     }
   }
   return WRC_Continue;
 } 
 
 /*
 ** Call sqlite3WalkExpr() for every expression in Select statement p.
 ** Invoke sqlite3WalkSelect() for subqueries in the FROM clause and
-** on the compound select chain, p->pPrior.
+** on the compound select chain, p->pPrior. 
+**
+** If it is not NULL, the xSelectCallback() callback is invoked before
+** the walk of the expressions and FROM clause. The xSelectCallback2()
+** method, if it is not NULL, is invoked following the walk of the 
+** expressions and FROM clause.
 **
 ** Return WRC_Continue under normal conditions.  Return WRC_Abort if
 ** there is an abort request.
 **
 ** If the Walker does not have an xSelectCallback() then this routine
 ** is a no-op returning WRC_Continue.
 */
 int sqlite3WalkSelect(Walker *pWalker, Select *p){
   int rc;
-  if( p==0 || pWalker->xSelectCallback==0 ) return WRC_Continue;
+  if( p==0 || (pWalker->xSelectCallback==0 && pWalker->xSelectCallback2==0) ){
+    return WRC_Continue;
+  }
   rc = WRC_Continue;
-  while( p  ){
-    rc = pWalker->xSelectCallback(pWalker, p);
-    if( rc ) break;
-    if( sqlite3WalkSelectExpr(pWalker, p) ) return WRC_Abort;
-    if( sqlite3WalkSelectFrom(pWalker, p) ) return WRC_Abort;
+  pWalker->walkerDepth++;
+  while( p ){
+    if( pWalker->xSelectCallback ){
+       rc = pWalker->xSelectCallback(pWalker, p);
+       if( rc ) break;
+    }
+    if( sqlite3WalkSelectExpr(pWalker, p)
+     || sqlite3WalkSelectFrom(pWalker, p)
+    ){
+      pWalker->walkerDepth--;
+      return WRC_Abort;
+    }
+    if( pWalker->xSelectCallback2 ){
+      pWalker->xSelectCallback2(pWalker, p);
+    }
     p = p->pPrior;
   }
+  pWalker->walkerDepth--;
   return rc & WRC_Abort;
 }