SQLite

*/
#ifndef SQLITE_OMIT_SUBQUERY
int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
  Select *p;                            /* SELECT to the right of IN operator */
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  int mustBeUnique = (prNotFound==0);   /* True if RHS must be unique */
  Vdbe *v = sqlite3GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );

  /* Check to see if an existing table or index can be used to
  ** satisfy the query.  This is preferable to generating a new 
  ** ephemeral table.
  */
  p = (ExprHasProperty(pX, EP_xIsSelect) ? pX->x.pSelect : 0);
  if( ALWAYS(pParse->nErr==0) && isCandidateForInOpt(p) ){
    sqlite3 *db = pParse->db;              /* Database connection */

    Table *pTab;                           /* Table <table>. */
    Expr *pExpr;                           /* Expression <column> */
    int iCol;                              /* Index of column <column> */
    int iDb;                               /* Database idx for pTab */

    assert( p );                        /* Because of isCandidateForInOpt(p) */
    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */

                               pKey,P4_KEYINFO_HANDOFF);
          VdbeComment((v, "%s", pIdx->zName));
          eType = IN_INDEX_INDEX;

          sqlite3VdbeJumpHere(v, iAddr);
          if( prNotFound && !pTab->aCol[iCol].notNull ){
            *prNotFound = ++pParse->nMem;
            sqlite3VdbeAddOp2(v, OP_Null, 0, *prNotFound);
          }
        }
      }
    }
  }

  if( eType==0 ){
    /* Could not found an existing table or index to use as the RHS b-tree.
    ** We will have to generate an ephemeral table to do the job.
    */
    double savedNQueryLoop = pParse->nQueryLoop;
    int rMayHaveNull = 0;
    eType = IN_INDEX_EPH;
    if( prNotFound ){
      *prNotFound = rMayHaveNull = ++pParse->nMem;
      sqlite3VdbeAddOp2(v, OP_Null, 0, *prNotFound);
    }else{
      testcase( pParse->nQueryLoop>(double)1 );
      pParse->nQueryLoop = (double)1;
      if( pX->pLeft->iColumn<0 && !ExprHasAnyProperty(pX, EP_xIsSelect) ){
        eType = IN_INDEX_ROWID;
      }
    }

  assert( v );   /* We failed long ago if this is not so */
  for(p = pParse->pAinc; p; p = p->pNext){
    pDb = &db->aDb[p->iDb];
    memId = p->regCtr;
    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
    addr = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp2(v, OP_Null, 0, memId+1);
    sqlite3VdbeAddOp4(v, OP_String8, 0, memId-1, 0, p->pTab->zName, 0);
    sqlite3VdbeAddOp2(v, OP_Rewind, 0, addr+9);
    sqlite3VdbeAddOp3(v, OP_Column, 0, 0, memId);
    sqlite3VdbeAddOp3(v, OP_Ne, memId-1, addr+7, memId);
    sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
    sqlite3VdbeAddOp2(v, OP_Rowid, 0, memId+1);
    sqlite3VdbeAddOp3(v, OP_Column, 0, 1, memId);

  addr = sqlite3VdbeCurrentAddr(v);
  iContinue = sqlite3VdbeMakeLabel(v);

  /* Suppress duplicates for UNION, EXCEPT, and INTERSECT 
  */
  if( regPrev ){
    int j1, j2;
    j1 = sqlite3VdbeAddOp1(v, OP_JumpOnce, pParse->nOnce++);
    j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iMem, regPrev+1, pIn->nMem,
                              (char*)pKeyInfo, p4type);
    sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
    sqlite3VdbeJumpHere(v, j1);
    sqlite3ExprCodeCopy(pParse, pIn->iMem, regPrev+1, pIn->nMem);

  }
  if( pParse->db->mallocFailed ) return 0;

  /* Suppress the the first OFFSET entries if there is an OFFSET clause
  */
  codeOffset(v, p, iContinue);

      pParse->nMem += pGroupBy->nExpr;
      iBMem = pParse->nMem + 1;
      pParse->nMem += pGroupBy->nExpr;
      sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag);
      VdbeComment((v, "clear abort flag"));
      sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
      VdbeComment((v, "indicate accumulator empty"));
      sqlite3VdbeAddOp3(v, OP_Null, 0, iAMem, iAMem+pGroupBy->nExpr-1);

      /* Begin a loop that will extract all source rows in GROUP BY order.
      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);

#endif
  int newmask;           /* Mask of NEW.* columns accessed by BEFORE triggers */

  /* Register Allocations */
  int regRowCount = 0;   /* A count of rows changed */
  int regOldRowid;       /* The old rowid */
  int regNewRowid;       /* The new rowid */
  int regNew;            /* Content of the NEW.* table in triggers */
  int regOld = 0;        /* Content of OLD.* table in triggers */
  int regRowSet = 0;     /* Rowset of rows to be updated */

  memset(&sContext, 0, sizeof(sContext));
  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){
    goto update_cleanup;
  }

    pWhere = 0;
    pTabList = 0;
    goto update_cleanup;
  }
#endif

  /* Allocate required registers. */
  regRowSet = ++pParse->nMem;
  regOldRowid = regNewRowid = ++pParse->nMem;
  if( pTrigger || hasFK ){
    regOld = pParse->nMem + 1;
    pParse->nMem += pTab->nCol;
  }
  if( chngRowid || pTrigger || hasFK ){
    regNewRowid = ++pParse->nMem;

  */
  if( sqlite3ResolveExprNames(&sNC, pWhere) ){
    goto update_cleanup;
  }

  /* Begin the database scan
  */
  sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
  pWInfo = sqlite3WhereBegin(
      pParse, pTabList, pWhere, 0, 0, WHERE_ONEPASS_DESIRED
  );
  if( pWInfo==0 ) goto update_cleanup;
  okOnePass = pWInfo->okOnePass;

  /* Remember the rowid of every item to be updated.
  */
  sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regOldRowid);
  if( !okOnePass ){

    sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, regOldRowid);
  }

  /* End the database scan loop.
  */
  sqlite3WhereEnd(pWInfo);

  ** the database after the BEFORE triggers are fired anyway (as the trigger 
  ** may have modified them). So not loading those that are not going to
  ** be used eliminates some redundant opcodes.
  */
  newmask = sqlite3TriggerColmask(
      pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
  );
  sqlite3VdbeAddOp3(v, OP_Null, 0, regNew, regNew+pTab->nCol-1);
  for(i=0; i<pTab->nCol; i++){
    if( i==pTab->iPKey ){
      /*sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);*/
    }else{
      j = aXRef[i];
      if( j>=0 ){
        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regNew+i);
      }else if( 0==(tmask&TRIGGER_BEFORE) || i>31 || (newmask&(1<<i)) ){
        /* This branch loads the value of a column that will not be changed 
        ** into a register. This is done if there are no BEFORE triggers, or

}

/* Opcode:  Gosub P1 P2 * * *
**
** Write the current address onto register P1
** and then jump to address P2.
*/
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);
  pIn1->flags = MEM_Int;
  pIn1->u.i = pc;
  REGISTER_TRACE(pOp->p1, pIn1);
  pc = pOp->p2 - 1;

  pOut->z = pOp->p4.z;
  pOut->n = pOp->p1;
  pOut->enc = encoding;
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Null * P2 P3 * *
**
** 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;
}


/* Opcode: Blob P1 P2 * P4
**
** P4 points to a blob of data P1 bytes long.  Store this

  break;
}

/* Opcode: Once P1 P2 * * *
**
** 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.
**
** 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: JumpOnce P1 P2 * * *
**
** Check if OP_Once flag P1 is clear. If so, set the flag and
** jump to instruction P2. Otherwise fall through.
**
** See also: Once
*/
case OP_JumpOnce: {         /* jump */
  assert( pOp->p1<p->nOnceFlag );
  if( !p->aOnceFlag[pOp->p1] ){
    pc = pOp->p2-1;
    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 non-zero.
*/
/* Opcode: IfNot P1 P2 P3 * *
**
** Jump to P2 if the value in register P1 is False.  The value
** 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_If:                 /* jump, in1 */
case OP_IfNot: {            /* jump, in1 */
  int c;
  pIn1 = &aMem[pOp->p1];
  if( pIn1->flags & MEM_Null ){
    c = pOp->p3;

  Mem *pEnd;              /* Last memory cell in new array */
  VdbeFrame *pFrame;      /* New vdbe frame to execute in */
  SubProgram *pProgram;   /* Sub-program to execute */
  void *t;                /* Token identifying trigger */

  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 
  ** disabled for backwards compatibility (p5 is set if this sub-program
  ** is really a trigger, not a foreign key action, and the flag set
  ** and cleared by the "PRAGMA recursive_triggers" command is clear).
  ** 

  VdbeFrame *pFrame;
  if( p->pFrame ){
    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
    pIn1 = &pFrame->aMem[pOp->p1];
  }else{
    pIn1 = &aMem[pOp->p1];
  }
  /*assert( memIsValid(pIn1) );  FIXME */
  sqlite3VdbeMemIntegerify(pIn1);
  pIn2 = &aMem[pOp->p2];
  sqlite3VdbeMemIntegerify(pIn2);
  if( pIn1->u.i<pIn2->u.i){
    pIn1->u.i = pIn2->u.i;
  }
  break;

    }
    case P4_REAL: {
      sqlite3_snprintf(nTemp, zTemp, "%.16g", *pOp->p4.pReal);
      break;
    }
    case P4_MEM: {
      Mem *pMem = pOp->p4.pMem;

      if( pMem->flags & MEM_Str ){
        zP4 = pMem->z;
      }else if( pMem->flags & MEM_Int ){
        sqlite3_snprintf(nTemp, zTemp, "%lld", pMem->u.i);
      }else if( pMem->flags & MEM_Real ){
        sqlite3_snprintf(nTemp, zTemp, "%.16g", pMem->r);
      }else if( pMem->flags & MEM_Null ){
        sqlite3_snprintf(nTemp, zTemp, "NULL");
      }else{
        assert( pMem->flags & MEM_Blob );
        zP4 = "(blob)";
      }
      break;
    }
#ifndef SQLITE_OMIT_VIRTUALTABLE

      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_Frame|MEM_RowSet) ){
        sqlite3VdbeMemRelease(p);
      }else if( p->zMalloc ){
        sqlite3DbFree(db, p->zMalloc);
        p->zMalloc = 0;
      }

      p->flags = MEM_Invalid;
    }
    db->mallocFailed = malloc_failed;
  }
}

/*
** Delete a VdbeFrame object and its contents. VdbeFrame objects are

    nByte = 0;
    p->aMem = allocSpace(p->aMem, nMem*sizeof(Mem), &zCsr, zEnd, &nByte);
    p->aVar = allocSpace(p->aVar, nVar*sizeof(Mem), &zCsr, zEnd, &nByte);
    p->apArg = allocSpace(p->apArg, nArg*sizeof(Mem*), &zCsr, zEnd, &nByte);
    p->azVar = allocSpace(p->azVar, nVar*sizeof(char*), &zCsr, zEnd, &nByte);
    p->apCsr = allocSpace(p->apCsr, nCursor*sizeof(VdbeCursor*),
                          &zCsr, zEnd, &nByte);
    p->aOnceFlag = allocSpace(p->aOnceFlag, nOnce, &zCsr, zEnd, &nByte);

    if( nByte ){
      p->pFree = sqlite3DbMallocZero(db, nByte);
    }
    zCsr = p->pFree;
    zEnd = &zCsr[nByte];
  }while( nByte && !db->mallocFailed );

    memcpy(p->azVar, pParse->azVar, p->nzVar*sizeof(p->azVar[0]));
    memset(pParse->azVar, 0, pParse->nzVar*sizeof(pParse->azVar[0]));
  }
  if( p->aMem ){
    p->aMem--;                      /* aMem[] goes from 1..nMem */
    p->nMem = nMem;                 /*       not from 0..nMem-1 */
    for(n=1; n<=nMem; n++){
      p->aMem[n].flags = MEM_Invalid;
      p->aMem[n].db = db;
    }
  }
  if( p->aOnceFlag ) memset(p->aOnceFlag, 0, p->nOnceFlag);
  p->explain = pParse->explain;
  sqlite3VdbeRewind(p);
}

/*
** Close a VDBE cursor and release all the resources that cursor 
** happens to hold.

    releaseMemArray(&p->aMem[1], p->nMem);
  }
  while( p->pDelFrame ){
    VdbeFrame *pDel = p->pDelFrame;
    p->pDelFrame = pDel->pParent;
    sqlite3VdbeFrameDelete(pDel);
  }

}

/*
** Clean up the VM after execution.
**
** This routine will automatically close any cursors, lists, and/or
** sorters that were left open.  It also deletes the values of
** variables in the aVar[] array.
*/
static void Cleanup(Vdbe *p){
  sqlite3 *db = p->db;

#ifdef SQLITE_DEBUG
  /* Execute assert() statements to ensure that the Vdbe.apCsr[] and 
  ** Vdbe.aMem[] arrays have already been cleaned up.  */
  int i;
  if( p->apCsr ) for(i=0; i<p->nCursor; i++) assert( p->apCsr[i]==0 );
  if( p->aMem ){
    for(i=1; i<=p->nMem; i++) assert( p->aMem[i].flags==MEM_Invalid );
  }
#endif

  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = 0;
  p->pResultSet = 0;
}

  ** state.  We need to rollback the statement transaction, if there is
  ** one, or the complete transaction if there is no statement transaction.
  */

  if( p->db->mallocFailed ){
    p->rc = SQLITE_NOMEM;
  }
  if( p->aOnceFlag ) memset(p->aOnceFlag, 0, p->nOnceFlag);
  closeAllCursors(p);
  if( p->magic!=VDBE_MAGIC_RUN ){
    return SQLITE_OK;
  }
  checkActiveVdbeCnt(db);

  /* No commit or rollback needed if the program never started */