1 files changed, 42 insertions, 22 deletions

diff --git a/src/vdbe.c b/src/vdbe.c
index e7fa05037..64ae54e3d 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -764,7 +764,8 @@ case OP_Goto: {             /* jump */
 ** Write the current address onto register P1
 ** and then jump to address P2.
 */
-case OP_Gosub: {            /* jump, in1 */
+case OP_Gosub: {            /* jump */
+  assert( pOp->p1>0 && pOp->p1<=p->nMem );
   pIn1 = &aMem[pOp->p1];
   assert( (pIn1->flags & MEM_Dyn)==0 );
   memAboutToChange(p, pIn1);
@@ -961,12 +962,25 @@ case OP_String: {          /* out2-prerelease */
   break;
 }
 
-/* Opcode: Null * P2 * * *
+/* Opcode: Null * P2 P3 * *
 **
-** Write a NULL into register P2.
+** Write a NULL into registers P2.  If P3 greater than P2, then also write
+** NULL into register P3 and ever register in between P2 and P3.  If P3
+** is less than P2 (typically P3 is zero) then only register P2 is
+** set to NULL
 */
 case OP_Null: {           /* out2-prerelease */
+  int cnt;
+  cnt = pOp->p3-pOp->p2;
+  assert( pOp->p3<=p->nMem );
   pOut->flags = MEM_Null;
+  while( cnt>0 ){
+    pOut++;
+    memAboutToChange(p, pOut);
+    MemReleaseExt(pOut);
+    pOut->flags = MEM_Null;
+    cnt--;
+  }
   break;
 }
 
@@ -2023,27 +2037,33 @@ case OP_BitNot: {             /* same as TK_BITNOT, in1, out2 */
 
 /* Opcode: Once P1 P2 * * *
 **
-** Jump to P2 if the value in register P1 is a not null or zero.  If
-** the value is NULL or zero, fall through and change the P1 register
-** to an integer 1.
+** Check if OP_Once flag P1 is set. If so, jump to instruction P2. Otherwise,
+** set the flag and fall through to the next instruction.
 **
-** When P1 is not used otherwise in a program, this opcode falls through
-** once and jumps on all subsequent invocations.  It is the equivalent
-** of "OP_If P1 P2", followed by "OP_Integer 1 P1".
+** See also: JumpOnce
 */
+case OP_Once: {             /* jump */
+  assert( pOp->p1<p->nOnceFlag );
+  if( p->aOnceFlag[pOp->p1] ){
+    pc = pOp->p2-1;
+  }else{
+    p->aOnceFlag[pOp->p1] = 1;
+  }
+  break;
+}
+
 /* Opcode: If P1 P2 P3 * *
 **
 ** Jump to P2 if the value in register P1 is true.  The value
 ** is considered true if it is numeric and non-zero.  If the value
-** in P1 is NULL then take the jump if P3 is true.
+** in P1 is NULL then take the jump if P3 is non-zero.
 */
 /* Opcode: IfNot P1 P2 P3 * *
 **
 ** Jump to P2 if the value in register P1 is False.  The value
-** is considered true if it has a numeric value of zero.  If the value
-** in P1 is NULL then take the jump if P3 is true.
+** is considered false if it has a numeric value of zero.  If the value
+** in P1 is NULL then take the jump if P3 is zero.
 */
-case OP_Once:               /* jump, in1 */
 case OP_If:                 /* jump, in1 */
 case OP_IfNot: {            /* jump, in1 */
   int c;
@@ -2060,12 +2080,6 @@ case OP_IfNot: {            /* jump, in1 */
   }
   if( c ){
     pc = pOp->p2-1;
-  }else if( pOp->opcode==OP_Once ){
-    assert( (pIn1->flags & (MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame))==0 );
-    memAboutToChange(p, pIn1);
-    pIn1->flags = MEM_Int;
-    pIn1->u.i = 1;
-    REGISTER_TRACE(pOp->p1, pIn1);
   }
   break;
 }
@@ -5071,7 +5085,6 @@ case OP_Program: {        /* jump */
 
   pProgram = pOp->p4.pProgram;
   pRt = &aMem[pOp->p3];
-  assert( memIsValid(pRt) );
   assert( pProgram->nOp>0 );
   
   /* If the p5 flag is clear, then recursive invocation of triggers is 
@@ -5110,7 +5123,8 @@ case OP_Program: {        /* jump */
     nMem = pProgram->nMem + pProgram->nCsr;
     nByte = ROUND8(sizeof(VdbeFrame))
               + nMem * sizeof(Mem)
-              + pProgram->nCsr * sizeof(VdbeCursor *);
+              + pProgram->nCsr * sizeof(VdbeCursor *)
+              + pProgram->nOnce * sizeof(u8);
     pFrame = sqlite3DbMallocZero(db, nByte);
     if( !pFrame ){
       goto no_mem;
@@ -5130,10 +5144,12 @@ case OP_Program: {        /* jump */
     pFrame->aOp = p->aOp;
     pFrame->nOp = p->nOp;
     pFrame->token = pProgram->token;
+    pFrame->aOnceFlag = p->aOnceFlag;
+    pFrame->nOnceFlag = p->nOnceFlag;
 
     pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
     for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
-      pMem->flags = MEM_Null;
+      pMem->flags = MEM_Invalid;
       pMem->db = db;
     }
   }else{
@@ -5155,7 +5171,11 @@ case OP_Program: {        /* jump */
   p->apCsr = (VdbeCursor **)&aMem[p->nMem+1];
   p->aOp = aOp = pProgram->aOp;
   p->nOp = pProgram->nOp;
+  p->aOnceFlag = (u8 *)&p->apCsr[p->nCursor];
+  p->nOnceFlag = pProgram->nOnce;
+  p->nOp = pProgram->nOp;
   pc = -1;
+  memset(p->aOnceFlag, 0, p->nOnceFlag);
 
   break;
 }