vdbeaux.c

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static void freeP3(int p3type, void *p3){
  if( p3 ){
    switch( p3type ){
      case P3_REAL:
      case P3_INT64:
      case P3_MPRINTF:
      case P3_DYNAMIC:
      case P3_KEYINFO:
      case P3_KEYINFO_HANDOFF: {
        sqlite3_free(p3);
        break;
      }
      case P3_VDBEFUNC: {
        VdbeFunc *pVdbeFunc = (VdbeFunc *)p3;
        freeEphemeralFunction(pVdbeFunc->pFunc);
        sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);
        sqlite3_free(pVdbeFunc);
        break;
      }
      case P3_FUNCDEF: {
        freeEphemeralFunction((FuncDef*)p3);
        break;
      }
      case P3_MEM: {
        sqlite3ValueFree((sqlite3_value*)p3);
        break;
      }
    }
  }
}


/*
** Change N opcodes starting at addr to No-ops.
*/
void sqlite3VdbeChangeToNoop(Vdbe *p, int addr, int N){
  if( p && p->aOp ){
    VdbeOp *pOp = &p->aOp[addr];
    while( N-- ){
      freeP3(pOp->p3type, pOp->p3);
      memset(pOp, 0, sizeof(pOp[0]));
      pOp->opcode = OP_Noop;
      pOp++;
    }
  }
}

/*
** Change the value of the P3 operand for a specific instruction.
** This routine is useful when a large program is loaded from a
** static array using sqlite3VdbeAddOpList but we want to make a
** few minor changes to the program.
**
** If n>=0 then the P3 operand is dynamic, meaning that a copy of
** the string is made into memory obtained from sqlite3_malloc().
** A value of n==0 means copy bytes of zP3 up to and including the
** first null byte.  If n>0 then copy n+1 bytes of zP3.
**
** If n==P3_KEYINFO it means that zP3 is a pointer to a KeyInfo structure.
** A copy is made of the KeyInfo structure into memory obtained from
** sqlite3_malloc, to be freed when the Vdbe is finalized.
** n==P3_KEYINFO_HANDOFF indicates that zP3 points to a KeyInfo structure
** stored in memory that the caller has obtained from sqlite3_malloc. The 
** caller should not free the allocation, it will be freed when the Vdbe is
** finalized.
** 
** Other values of n (P3_STATIC, P3_COLLSEQ etc.) indicate that zP3 points
** to a string or structure that is guaranteed to exist for the lifetime of
** the Vdbe. In these cases we can just copy the pointer.
**
** If addr<0 then change P3 on the most recently inserted instruction.
*/
void sqlite3VdbeChangeP3(Vdbe *p, int addr, const char *zP3, int n){
  Op *pOp;
  assert( p==0 || p->magic==VDBE_MAGIC_INIT );
  if( p==0 || p->aOp==0 || p->db->mallocFailed ){
    if (n != P3_KEYINFO) {
      freeP3(n, (void*)*(char**)&zP3);
    }
    return;
  }
  if( addr<0 || addr>=p->nOp ){
    addr = p->nOp - 1;
    if( addr<0 ) return;
  }
  pOp = &p->aOp[addr];
  freeP3(pOp->p3type, pOp->p3);
  pOp->p3 = 0;
  if( zP3==0 ){
    pOp->p3 = 0;
    pOp->p3type = P3_NOTUSED;
  }else if( n==P3_KEYINFO ){
    KeyInfo *pKeyInfo;
    int nField, nByte;

    nField = ((KeyInfo*)zP3)->nField;
    nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]) + nField;
    pKeyInfo = sqlite3_malloc( nByte );
    pOp->p3 = (char*)pKeyInfo;
    if( pKeyInfo ){
      unsigned char *aSortOrder;
      memcpy(pKeyInfo, zP3, nByte);
      aSortOrder = pKeyInfo->aSortOrder;
      if( aSortOrder ){
        pKeyInfo->aSortOrder = (unsigned char*)&pKeyInfo->aColl[nField];
        memcpy(pKeyInfo->aSortOrder, aSortOrder, nField);
      }
      pOp->p3type = P3_KEYINFO;
    }else{
      p->db->mallocFailed = 1;
      pOp->p3type = P3_NOTUSED;
    }
  }else if( n==P3_KEYINFO_HANDOFF ){
    pOp->p3 = (char*)zP3;
    pOp->p3type = P3_KEYINFO;
  }else if( n<0 ){
    pOp->p3 = (char*)zP3;
    pOp->p3type = n;
  }else{
    if( n==0 ) n = strlen(zP3);
    pOp->p3 = sqlite3DbStrNDup(p->db, zP3, n);
    pOp->p3type = P3_DYNAMIC;
  }
}

#ifndef NDEBUG
/*
** Replace the P3 field of the most recently coded instruction with
** comment text.
*/
void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
  va_list ap;
  assert( p->nOp>0 || p->aOp==0 );
  assert( p->aOp==0 || p->aOp[p->nOp-1].p3==0 || p->db->mallocFailed );
  va_start(ap, zFormat);
  sqlite3VdbeChangeP3(p, -1, sqlite3VMPrintf(p->db, zFormat, ap), P3_DYNAMIC);
  va_end(ap);
}
#endif

/*
** Return the opcode for a given address.
*/
VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
  assert( p->magic==VDBE_MAGIC_INIT );
  assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
  return ((addr>=0 && addr<p->nOp)?(&p->aOp[addr]):0);
}

#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
/*
** Compute a string that describes the P3 parameter for an opcode.
** Use zTemp for any required temporary buffer space.
*/
static char *displayP3(Op *pOp, char *zTemp, int nTemp){
  char *zP3;
  assert( nTemp>=20 );
  switch( pOp->p3type ){
    case P3_KEYINFO: {
      int i, j;
      KeyInfo *pKeyInfo = (KeyInfo*)pOp->p3;
      sqlite3_snprintf(nTemp, zTemp, "keyinfo(%d", pKeyInfo->nField);
      i = strlen(zTemp);
      for(j=0; j<pKeyInfo->nField; j++){
        CollSeq *pColl = pKeyInfo->aColl[j];
        if( pColl ){
          int n = strlen(pColl->zName);
          if( i+n>nTemp-6 ){
            memcpy(&zTemp[i],",...",4);
            break;
          }
          zTemp[i++] = ',';
          if( pKeyInfo->aSortOrder && pKeyInfo->aSortOrder[j] ){
            zTemp[i++] = '-';
          }
          memcpy(&zTemp[i], pColl->zName,n+1);
          i += n;
        }else if( i+4<nTemp-6 ){
          memcpy(&zTemp[i],",nil",4);
          i += 4;
        }
      }
      zTemp[i++] = ')';
      zTemp[i] = 0;
      assert( i<nTemp );
      zP3 = zTemp;
      break;
    }
    case P3_COLLSEQ: {
      CollSeq *pColl = (CollSeq*)pOp->p3;
      sqlite3_snprintf(nTemp, zTemp, "collseq(%.20s)", pColl->zName);
      zP3 = zTemp;
      break;
    }
    case P3_FUNCDEF: {
      FuncDef *pDef = (FuncDef*)pOp->p3;
      sqlite3_snprintf(nTemp, zTemp, "%s(%d)", pDef->zName, pDef->nArg);
      zP3 = zTemp;
      break;
    }
    case P3_INT64: {
      sqlite3_snprintf(nTemp, zTemp, "%lld", *(sqlite3_int64*)pOp->p3);
      zP3 = zTemp;
      break;
    }
    case P3_REAL: {
      sqlite3_snprintf(nTemp, zTemp, "%.16g", *(double*)pOp->p3);
      zP3 = zTemp;
      break;
    }
#ifndef SQLITE_OMIT_VIRTUALTABLE
    case P3_VTAB: {
      sqlite3_vtab *pVtab = (sqlite3_vtab*)pOp->p3;
      sqlite3_snprintf(nTemp, zTemp, "vtab:%p:%p", pVtab, pVtab->pModule);
      zP3 = zTemp;
      break;
    }
#endif
    default: {
      zP3 = pOp->p3;
      if( zP3==0 || pOp->opcode==OP_Noop ){
        zP3 = "";
      }
    }
  }
  assert( zP3!=0 );
  return zP3;
}
#endif

/*
** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
**
*/
void sqlite3VdbeUsesBtree(Vdbe *p, int i){
  int mask;
  assert( i>=0 && i<p->db->nDb );
  assert( i<sizeof(p->btreeMask)*8 );
  mask = 1<<i;
  if( (p->btreeMask & mask)==0 ){
    p->btreeMask |= mask;
    sqlite3BtreeMutexArrayInsert(&p->aMutex, p->db->aDb[i].pBt);
  }
}


#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
/*
** Print a single opcode.  This routine is used for debugging only.
*/
void sqlite3VdbePrintOp(FILE *pOut, int pc, Op *pOp){
  char *zP3;
  char zPtr[50];
  static const char *zFormat1 = "%4d %-13s %4d %4d %s\n";
  if( pOut==0 ) pOut = stdout;
  zP3 = displayP3(pOp, zPtr, sizeof(zPtr));
  fprintf(pOut, zFormat1,
      pc, sqlite3OpcodeName(pOp->opcode), pOp->p1, pOp->p2, zP3);
  fflush(pOut);
}
#endif

/*
** Release an array of N Mem elements
*/
static void releaseMemArray(Mem *p, int N){
  if( p ){
    while( N-->0 ){
      assert( N<2 || p[0].db==p[1].db );
      sqlite3VdbeMemRelease(p++);
    }
  }
}

#ifndef SQLITE_OMIT_EXPLAIN
/*
** Give a listing of the program in the virtual machine.
**
** The interface is the same as sqlite3VdbeExec().  But instead of
** running the code, it invokes the callback once for each instruction.
** This feature is used to implement "EXPLAIN".
*/
int sqlite3VdbeList(
  Vdbe *p                   /* The VDBE */
){
  sqlite3 *db = p->db;
  int i;
  int rc = SQLITE_OK;

  assert( p->explain );
  if( p->magic!=VDBE_MAGIC_RUN ) return SQLITE_MISUSE;
  assert( db->magic==SQLITE_MAGIC_BUSY );
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );

  /* Even though this opcode does not put dynamic strings onto the
  ** the stack, they may become dynamic if the user calls
  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
  */
  if( p->pTos==&p->aStack[4] ){
    releaseMemArray(p->aStack, 5);
  }
  p->resOnStack = 0;

  do{
    i = p->pc++;
  }while( i<p->nOp && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
  if( i>=p->nOp ){
    p->rc = SQLITE_OK;
    rc = SQLITE_DONE;
  }else if( db->u1.isInterrupted ){
    p->rc = SQLITE_INTERRUPT;
    rc = SQLITE_ERROR;
    sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(p->rc), (char*)0);
  }else{
    Op *pOp = &p->aOp[i];
    Mem *pMem = p->aStack;
    pMem->flags = MEM_Int;
    pMem->type = SQLITE_INTEGER;
    pMem->u.i = i;                                /* Program counter */
    pMem++;

    pMem->flags = MEM_Static|MEM_Str|MEM_Term;
    pMem->z = (char*)sqlite3OpcodeName(pOp->opcode);  /* Opcode */
    assert( pMem->z!=0 );
    pMem->n = strlen(pMem->z);
    pMem->type = SQLITE_TEXT;
    pMem->enc = SQLITE_UTF8;
    pMem++;

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p1;                          /* P1 */
    pMem->type = SQLITE_INTEGER;
    pMem++;

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p2;                          /* P2 */
    pMem->type = SQLITE_INTEGER;
    pMem++;

    pMem->flags = MEM_Ephem|MEM_Str|MEM_Term;   /* P3 */
    pMem->z = displayP3(pOp, pMem->zShort, sizeof(pMem->zShort));
    assert( pMem->z!=0 );
    pMem->n = strlen(pMem->z);
    pMem->type = SQLITE_TEXT;
    pMem->enc = SQLITE_UTF8;

    p->nResColumn = 5 - 2*(p->explain-1);
    p->pTos = pMem;
    p->rc = SQLITE_OK;
    p->resOnStack = 1;
    rc = SQLITE_ROW;
  }
  return rc;
}
#endif /* SQLITE_OMIT_EXPLAIN */

#ifdef SQLITE_DEBUG
/*
** Print the SQL that was used to generate a VDBE program.
*/
void sqlite3VdbePrintSql(Vdbe *p){
  int nOp = p->nOp;
  VdbeOp *pOp;
  if( nOp<1 ) return;
  pOp = &p->aOp[nOp-1];
  if( pOp->opcode==OP_Noop && pOp->p3!=0 ){
    const char *z = pOp->p3;
    while( isspace(*(u8*)z) ) z++;
    printf("SQL: [%s]\n", z);
  }
}
#endif

#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
/*
** Print an IOTRACE message showing SQL content.
*/
void sqlite3VdbeIOTraceSql(Vdbe *p){
  int nOp = p->nOp;
  VdbeOp *pOp;
  if( sqlite3_io_trace==0 ) return;
  if( nOp<1 ) return;
  pOp = &p->aOp[nOp-1];
  if( pOp->opcode==OP_Noop && pOp->p3!=0 ){
    int i, j;
    char z[1000];
    sqlite3_snprintf(sizeof(z), z, "%s", pOp->p3);
    for(i=0; isspace((unsigned char)z[i]); i++){}
    for(j=0; z[i]; i++){
      if( isspace((unsigned char)z[i]) ){
        if( z[i-1]!=' ' ){
          z[j++] = ' ';
        }
      }else{
        z[j++] = z[i];
      }
    }
    z[j] = 0;
    sqlite3_io_trace("SQL %s\n", z);
  }
}
#endif /* !SQLITE_OMIT_TRACE && SQLITE_ENABLE_IOTRACE */


/*
** Prepare a virtual machine for execution.  This involves things such
** as allocating stack space and initializing the program counter.
** After the VDBE has be prepped, it can be executed by one or more
** calls to sqlite3VdbeExec().  
**
** This is the only way to move a VDBE from VDBE_MAGIC_INIT to
** VDBE_MAGIC_RUN.
*/
void sqlite3VdbeMakeReady(
  Vdbe *p,                       /* The VDBE */
  int nVar,                      /* Number of '?' see in the SQL statement */
  int nMem,                      /* Number of memory cells to allocate */
  int nCursor,                   /* Number of cursors to allocate */
  int isExplain                  /* True if the EXPLAIN keywords is present */
){
  int n;
  sqlite3 *db = p->db;

  assert( p!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );

  /* There should be at least one opcode.
  */
  assert( p->nOp>0 );

  /* Set the magic to VDBE_MAGIC_RUN sooner rather than later. This
   * is because the call to resizeOpArray() below may shrink the
   * p->aOp[] array to save memory if called when in VDBE_MAGIC_RUN 
   * state.
   */
  p->magic = VDBE_MAGIC_RUN;

  /* No instruction ever pushes more than a single element onto the
  ** stack.  And the stack never grows on successive executions of the