Use the VList object to replace Parse.azVar for tracking the mapping between

SQL parameter names and parameter numbers.  There is a performance
improvement, though there are still a few hiccups in the current code.

FossilOrigin-Name: 68ecafa1425a41358c88f41efea3262f1b4490f2

1 files changed, 10 insertions, 25 deletions

diff --git a/src/expr.c b/src/expr.c
index 60843bf52..ae6107449 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -934,7 +934,7 @@ Expr *sqlite3ExprFunction(Parse *pParse, ExprList *pList, Token *pToken){
 ** variable number.
 **
 ** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
-** sure "nnn" is not too be to avoid a denial of service attack when
+** sure "nnn" is not too big to avoid a denial of service attack when
 ** the SQL statement comes from an external source.
 **
 ** Wildcards of the form ":aaa", "@aaa", or "$aaa" are assigned the same number
@@ -981,30 +981,13 @@ void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr, u32 n){
       ** number as the prior appearance of the same name, or if the name
       ** has never appeared before, reuse the same variable number
       */
-      ynVar i;
-      for(i=x=0; i<pParse->nzVar; i++){
-        if( pParse->azVar[i] && strcmp(pParse->azVar[i],z)==0 ){
-          x = (ynVar)i+1;
-          break;
-        }
+      x = (ynVar)sqlite3VListNameToNum(pParse->pVList, z, n);
+      if( x==0 ){
+        x = (ynVar)(++pParse->nVar);
+        pParse->pVList = sqlite3VListAdd(db, pParse->pVList, z, n, x);
       }
-      if( x==0 ) x = (ynVar)(++pParse->nVar);
     }
     pExpr->iColumn = x;
-    if( x>pParse->nzVar ){
-      char **a;
-      a = sqlite3DbRealloc(db, pParse->azVar, x*sizeof(a[0]));
-      if( a==0 ){
-        assert( db->mallocFailed ); /* Error reported through mallocFailed */
-        return;
-      }
-      pParse->azVar = a;
-      memset(&a[pParse->nzVar], 0, (x-pParse->nzVar)*sizeof(a[0]));
-      pParse->nzVar = x;
-    }
-    if( pParse->azVar[x-1]==0 ){
-      pParse->azVar[x-1] = sqlite3DbStrNDup(db, z, n);
-    }
   } 
   if( pParse->nVar>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
     sqlite3ErrorMsg(pParse, "too many SQL variables");
@@ -3430,9 +3413,11 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       assert( pExpr->u.zToken[0]!=0 );
       sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iColumn, target);
       if( pExpr->u.zToken[1]!=0 ){
-        assert( pExpr->u.zToken[0]=='?' 
-             || strcmp(pExpr->u.zToken, pParse->azVar[pExpr->iColumn-1])==0 );
-        sqlite3VdbeAppendP4(v, pParse->azVar[pExpr->iColumn-1], P4_STATIC);
+        const char *z = sqlite3VListNumToName(pParse->pVList, pExpr->iColumn);
+        if( z ){
+          assert( pExpr->u.zToken[0]=='?' || strcmp(pExpr->u.zToken, z)==0 );
+          sqlite3VdbeAppendP4(v, (char*)z, P4_STATIC);
+        }
       }
       return target;
     }