SQLite

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**
** $Id: vdbe.c,v 1.370 2004/06/12 20:12:51 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  }else if( pRight ){
    pTail->pNext = pRight;
  }
  return sHead.pNext;
}

/*


** Allocate cursor number iCur.  Return a pointer to it.  Return NULL
** if we run out of memory.


*/
static Cursor *allocateCursor(Vdbe *p, int iCur){
  Cursor *pCx;
  if( iCur>=p->nCursor ){
    int i;
    p->apCsr = sqliteRealloc( p->apCsr, (iCur+1)*sizeof(Cursor*) );
    if( p->apCsr==0 ){
      p->nCursor = 0;
      return 0;
    }
    for(i=p->nCursor; i<iCur; i++){
      p->apCsr[i] = 0;

    }
    p->nCursor = iCur+1;
  }else if( p->apCsr[iCur] ){
    sqlite3VdbeFreeCursor(p->apCsr[iCur]);
  }
  p->apCsr[iCur] = pCx = sqliteMalloc( sizeof(Cursor) );
  return pCx;
}

/*
** Apply any conversion required by the supplied column affinity to
** memory cell pRec. affinity may be one of:
**
** SQLITE_AFF_NUMERIC

** Before the OP_Column opcode can be executed on a cursor, this
** opcode must be called to set the number of fields in the table.
**
** This opcode sets the number of columns for cursor P1 to P2.
*/
case OP_SetNumColumns: {
  assert( (pOp->p1)<p->nCursor );
  assert( p->apCsr[pOp->p1]!=0 );
  p->apCsr[pOp->p1]->nField = pOp->p2;
  break;
}

/* Opcode: IdxColumn P1 * *
**
** P1 is a cursor opened on an index. Push the first field from the

  ** zRec is set to NULL.
  **
  ** We also compute the number of columns in the record.  For cursors,
  ** the number of columns is stored in the Cursor.nField element.  For
  ** records on the stack, the next entry down on the stack is an integer
  ** which is the number of records.
  */
  assert( p1<0 || p->apCsr[p1]!=0 );
  if( p1<0 ){
    /* Take the record off of the stack */
    Mem *pRec = &pTos[p1];
    Mem *pCnt = &pRec[-1];
    assert( pRec>=p->aStack );
    assert( pRec->flags & MEM_Blob );
    payloadSize = pRec->n;

    if( p2<2 ){
      sqlite3SetString(&p->zErrMsg, "root page number less than 2", (char*)0);
      rc = SQLITE_INTERNAL;
      break;
    }
  }
  assert( i>=0 );

  pCur = allocateCursor(p, i);
  if( pCur==0 ) goto no_mem;
  pCur->nullRow = 1;
  if( pX==0 ) break;
  /* We always provide a key comparison function.  If the table being
  ** opened is of type INTKEY, the comparision function will be ignored. */
  rc = sqlite3BtreeCursor(pX, p2, wrFlag,
           sqlite3VdbeRecordCompare, pOp->p3,
           &pCur->pCursor);

** whereas "Temporary" in the context of CREATE TABLE means for the duration
** of the connection to the database.  Same word; different meanings.
*/
case OP_OpenTemp: {
  int i = pOp->p1;
  Cursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i);
  if( pCx==0 ) goto no_mem;



  pCx->nullRow = 1;
  rc = sqlite3BtreeFactory(db, 0, 1, TEMP_PAGES, &pCx->pBt);

  if( rc==SQLITE_OK ){
    rc = sqlite3BtreeBeginTrans(pCx->pBt, 1, 0);
  }
  if( rc==SQLITE_OK ){

** A pseudo-table created by this opcode is useful for holding the
** NEW or OLD tables in a trigger.
*/
case OP_OpenPseudo: {
  int i = pOp->p1;
  Cursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i);
  if( pCx==0 ) goto no_mem;



  pCx->nullRow = 1;
  pCx->pseudoTable = 1;
  pCx->pIncrKey = &pCx->bogusIncrKey;
  break;
}

/* Opcode: Close P1 * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.
*/
case OP_Close: {
  int i = pOp->p1;
  if( i>=0 && i<p->nCursor ){
    sqlite3VdbeFreeCursor(p->apCsr[i]);
    p->apCsr[i] = 0;
  }
  break;
}

/* Opcode: MoveGe P1 P2 *
**
** Pop the top of the stack and use its value as a key.  Reposition

case OP_MoveGt: {
  int i = pOp->p1;
  Cursor *pC;

  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->pCursor!=0 ){
    int res, oc;
    oc = pOp->opcode;
    pC->nullRow = 0;
    *pC->pIncrKey = oc==OP_MoveGt || oc==OP_MoveLe;
    if( pC->intKey ){
      i64 iKey;

case OP_NotFound:
case OP_Found: {
  int i = pOp->p1;
  int alreadyExists = 0;
  Cursor *pC;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor!=0 ){
    int res, rx;
    assert( pC->intKey==0 );
    Stringify(pTos, db->enc);
    rx = sqlite3BtreeMoveto(pC->pCursor, pTos->z, pTos->n, &res);
    alreadyExists = rx==SQLITE_OK && res==0;
    pC->deferredMoveto = 0;

  */
  assert( pNos>=p->aStack );
  Integerify(pTos, db->enc);
  R = pTos->i;
  pTos--;
  assert( i>=0 && i<=p->nCursor );
  pCx = p->apCsr[i];
  assert( pCx!=0 );
  pCrsr = pCx->pCursor;
  if( pCrsr!=0 ){
    int res, rc;
    i64 v;         /* The record number on the P1 entry that matches K */
    char *zKey;    /* The value of K */
    int nKey;      /* Number of bytes in K */
    int len;       /* Number of bytes in K without the rowid at the end */

*/
case OP_NotExists: {
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res, rx;
    u64 iKey;
    assert( pTos->flags & MEM_Int );
    assert( p->apCsr[i]->intKey );
    iKey = intToKey(pTos->i);
    rx = sqlite3BtreeMoveto(pCrsr, 0, iKey, &res);

** onto the stack.
*/
case OP_NewRecno: {
  int i = pOp->p1;
  i64 v = 0;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor==0 ){
    /* The zero initialization above is all that is needed */
  }else{
    /* The next rowid or record number (different terms for the same
    ** thing) is obtained in a two-step algorithm.
    **
    ** First we attempt to find the largest existing rowid and add one

case OP_PutIntKey:
case OP_PutStrKey: {
  Mem *pNos = &pTos[-1];
  int i = pOp->p1;
  Cursor *pC;
  assert( pNos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( ((pC = p->apCsr[i])->pCursor!=0 || pC->pseudoTable) ){
    char *zKey;
    i64 nKey; 
    i64 iKey;
    if( pOp->opcode==OP_PutStrKey ){
      Stringify(pNos, db->enc);
      nKey = pNos->n;

** If P1 is a pseudo-table, then this instruction is a no-op.
*/
case OP_Delete: {
  int i = pOp->p1;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->pCursor!=0 ){
    sqlite3VdbeCursorMoveto(pC);
    rc = sqlite3BtreeDelete(pC->pCursor);
    pC->nextRowidValid = 0;
    pC->cacheValid = 0;
  }
  if( pOp->p2 & OPFLAG_NCHANGE ) db->nChange++;

** processing compound selects.
*/
case OP_KeyAsData: {
  int i = pOp->p1;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pC->keyAsData = pOp->p2;
  break;
}

/* Opcode: RowData P1 * *
**
** Push onto the stack the complete row data for cursor P1.

  int i = pOp->p1;
  Cursor *pC;
  int n;

  pTos++;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->nullRow ){
    pTos->flags = MEM_Null;
  }else if( pC->pCursor!=0 ){
    BtCursor *pCrsr = pC->pCursor;
    sqlite3VdbeCursorMoveto(pC);
    if( pC->nullRow ){
      pTos->flags = MEM_Null;

case OP_Recno: {
  int i = pOp->p1;
  Cursor *pC;
  i64 v;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  sqlite3VdbeCursorMoveto(pC);
  pTos++;
  if( pC->recnoIsValid ){
    v = pC->lastRecno;
  }else if( pC->pseudoTable ){
    v = keyToInt(pC->iKey);
  }else if( pC->nullRow || pC->pCursor==0 ){

** This opcode may not be used on a pseudo-table.
*/
case OP_FullKey: {
  int i = pOp->p1;
  BtCursor *pCrsr;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( p->apCsr[i]->keyAsData );
  assert( !p->apCsr[i]->pseudoTable );

  pTos++;
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    u64 amt;
    char *z;

    sqlite3VdbeCursorMoveto(pC);
    assert( pC->intKey==0 );

*/
case OP_NullRow: {
  int i = pOp->p1;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pC->nullRow = 1;
  pC->recnoIsValid = 0;
  break;
}

/* Opcode: Last P1 P2 *
**
** The next use of the Recno or Column or Next instruction for P1 
** will refer to the last entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Last: {
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( (pCrsr = pC->pCursor)!=0 ){
    int res;
    rc = sqlite3BtreeLast(pCrsr, &res);
    pC->nullRow = res;
    pC->deferredMoveto = 0;
    pC->cacheValid = 0;
    if( res && pOp->p2>0 ){

  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  int res;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( (pCrsr = pC->pCursor)!=0 ){
    rc = sqlite3BtreeFirst(pCrsr, &res);
    pC->atFirst = res==0;
    pC->deferredMoveto = 0;
    pC->cacheValid = 0;
  }else{
    res = 1;

case OP_Next: {
  Cursor *pC;
  BtCursor *pCrsr;

  CHECK_FOR_INTERRUPT;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  if( (pCrsr = pC->pCursor)!=0 ){
    int res;
    if( pC->nullRow ){
      res = 1;
    }else{
      assert( pC->deferredMoveto==0 );
      rc = pOp->opcode==OP_Next ? sqlite3BtreeNext(pCrsr, &res) :

*/
case OP_IdxPut: {
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pTos->flags & MEM_Blob );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int nKey = pTos->n;
    const char *zKey = pTos->z;
    if( pOp->p2 ){
      int res;
      int len;

case OP_IdxDelete: {
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( pTos->flags & MEM_Blob );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int rx, res;
    rx = sqlite3BtreeMoveto(pCrsr, pTos->z, pTos->n, &res);
    if( rx==SQLITE_OK && res==0 ){
      rc = sqlite3BtreeDelete(pCrsr);
    }
    assert( pC->deferredMoveto==0 );

*/
case OP_IdxRecno: {
  int i = pOp->p1;
  BtCursor *pCrsr;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  pTos++;
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    i64 rowid;

    assert( pC->deferredMoveto==0 );
    assert( pC->intKey==0 );
    if( pC->nullRow ){

case OP_IdxGT:
case OP_IdxGE: {
  int i= pOp->p1;
  BtCursor *pCrsr;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pTos>=p->aStack );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res, rc;
 
    assert( pTos->flags & MEM_Blob );  /* Created using OP_Make*Key */
    Stringify(pTos, db->enc);
    assert( pC->deferredMoveto==0 );

** a row trigger.  The data for the row is stored in Cursor.pData and
** the rowid is in Cursor.iKey.
*/
struct Cursor {
  BtCursor *pCursor;    /* The cursor structure of the backend */
  i64 lastRecno;        /* Last recno from a Next or NextIdx operation */
  i64 nextRowid;        /* Next rowid returned by OP_NewRowid */
  Bool zeroed;          /* True if zeroed out and ready for reuse */
  Bool recnoIsValid;    /* True if lastRecno is valid */
  Bool keyAsData;       /* The OP_Column command works on key instead of data */
  Bool atFirst;         /* True if pointing to first entry */
  Bool useRandomRowid;  /* Generate new record numbers semi-randomly */
  Bool nullRow;         /* True if pointing to a row with no data */
  Bool nextRowidValid;  /* True if the nextRowid field is valid */
  Bool pseudoTable;     /* This is a NEW or OLD pseudo-tables of a trigger */

#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */
#define VDBE_MAGIC_HALT     0x519c2973    /* VDBE has completed execution */
#define VDBE_MAGIC_DEAD     0xb606c3c8    /* The VDBE has been deallocated */

/*
** Function prototypes
*/
void sqlite3VdbeFreeCursor(Cursor*);
void sqlite3VdbeSorterReset(Vdbe*);
int sqlite3VdbeAggReset(sqlite *, Agg *, KeyInfo *);
void sqlite3VdbeKeylistFree(Keylist*);
void sqliteVdbePopStack(Vdbe*,int);
int sqlite3VdbeCursorMoveto(Cursor*);
#if !defined(NDEBUG) || defined(VDBE_PROFILE)
void sqlite3VdbePrintOp(FILE*, int, Op*);

  }
}

/*
** Close a cursor and release all the resources that cursor happens
** to hold.
*/
void sqlite3VdbeFreeCursor(Cursor *pCx){
  if( pCx==0 ){
    return;
  }
  if( pCx->pCursor ){
    sqlite3BtreeCloseCursor(pCx->pCursor);
  }
  if( pCx->pBt ){
    sqlite3BtreeClose(pCx->pBt);
  }
  sqliteFree(pCx->pData);
  sqliteFree(pCx->aType);
  sqliteFree(pCx);
}

/*
** Close all cursors
*/
static void closeAllCursors(Vdbe *p){
  int i;
  for(i=0; i<p->nCursor; i++){
    sqlite3VdbeFreeCursor(p->apCsr[i]);


  }
  sqliteFree(p->apCsr);
  p->apCsr = 0;
  p->nCursor = 0;
}

/*