vdbe.c

SQLite 2.8.6 源代码,用来在Linux/Unix/Windows上编译安装.它是一个小型的数据库,但是非常好用,速度也快,一般的数据库查询之类的操作据统计比MySQL,PostgreSQL

  sqliteFree(pAgg->apFunc);
  pAgg->apFunc = 0;
  pAgg->pCurrent = 0;
  pAgg->pSearch = 0;
  pAgg->nMem = 0;
}

/*
** Insert a new aggregate element and make it the element that
** has focus.
**
** Return 0 on success and 1 if memory is exhausted.
*/
static int AggInsert(Agg *p, char *zKey, int nKey){
  AggElem *pElem, *pOld;
  int i;
  pElem = sqliteMalloc( sizeof(AggElem) + nKey +
                        (p->nMem-1)*sizeof(pElem->aMem[0]) );
  if( pElem==0 ) return 1;
  pElem->zKey = (char*)&pElem->aMem[p->nMem];
  memcpy(pElem->zKey, zKey, nKey);
  pElem->nKey = nKey;
  pOld = sqliteHashInsert(&p->hash, pElem->zKey, pElem->nKey, pElem);
  if( pOld!=0 ){
    assert( pOld==pElem );  /* Malloc failed on insert */
    sqliteFree(pOld);
    return 0;
  }
  for(i=0; i<p->nMem; i++){
    pElem->aMem[i].s.flags = STK_Null;
  }
  p->pCurrent = pElem;
  return 0;
}

/*
** Get the AggElem currently in focus
*/
#define AggInFocus(P)   ((P).pCurrent ? (P).pCurrent : _AggInFocus(&(P)))
static AggElem *_AggInFocus(Agg *p){
  HashElem *pElem = sqliteHashFirst(&p->hash);
  if( pElem==0 ){
    AggInsert(p,"",1);
    pElem = sqliteHashFirst(&p->hash);
  }
  return pElem ? sqliteHashData(pElem) : 0;
}

/*
** Convert the given stack entity into a string if it isn't one
** already.
*/
#define Stringify(P,I) if((aStack[I].flags & STK_Str)==0){hardStringify(P,I);}
static int hardStringify(Vdbe *p, int i){
  Stack *pStack = &p->aStack[i];
  int fg = pStack->flags;
  if( fg & STK_Real ){
    sprintf(pStack->z,"%.15g",pStack->r);
  }else if( fg & STK_Int ){
    sprintf(pStack->z,"%d",pStack->i);
  }else{
    pStack->z[0] = 0;
  }
  p->zStack[i] = pStack->z;
  pStack->n = strlen(pStack->z)+1;
  pStack->flags = STK_Str;
  return 0;
}

/*
** Convert the given stack entity into a string that has been obtained
** from sqliteMalloc().  This is different from Stringify() above in that
** Stringify() will use the NBFS bytes of static string space if the string
** will fit but this routine always mallocs for space.
** Return non-zero if we run out of memory.
*/
#define Dynamicify(P,I) ((aStack[I].flags & STK_Dyn)==0 ? hardDynamicify(P,I):0)
static int hardDynamicify(Vdbe *p, int i){
  Stack *pStack = &p->aStack[i];
  int fg = pStack->flags;
  char *z;
  if( (fg & STK_Str)==0 ){
    hardStringify(p, i);
  }
  assert( (fg & STK_Dyn)==0 );
  z = sqliteMallocRaw( pStack->n );
  if( z==0 ) return 1;
  memcpy(z, p->zStack[i], pStack->n);
  p->zStack[i] = z;
  pStack->flags |= STK_Dyn;
  return 0;
}

/*
** An ephemeral string value (signified by the STK_Ephem flag) contains
** a pointer to a dynamically allocated string where some other entity
** is responsible for deallocating that string.  Because the stack entry
** does not control the string, it might be deleted without the stack
** entry knowing it.
**
** This routine converts an ephemeral string into a dynamically allocated
** string that the stack entry itself controls.  In other words, it
** converts an STK_Ephem string into an STK_Dyn string.
*/
#define Deephemeralize(P,I) \
   if( ((P)->aStack[I].flags&STK_Ephem)!=0 && hardDeephem(P,I) ){ goto no_mem;}
static int hardDeephem(Vdbe *p, int i){
  Stack *pStack = &p->aStack[i];
  char **pzStack = &p->zStack[i];
  char *z;
  assert( (pStack->flags & STK_Ephem)!=0 );
  z = sqliteMallocRaw( pStack->n );
  if( z==0 ) return 1;
  memcpy(z, *pzStack, pStack->n);
  *pzStack = z;
  pStack->flags &= ~STK_Ephem;
  pStack->flags |= STK_Dyn;
  return 0;
}

/*
** Release the memory associated with the given stack level
*/
#define Release(P,I)  if((P)->aStack[I].flags&STK_Dyn){ hardRelease(P,I); }
static void hardRelease(Vdbe *p, int i){
  sqliteFree(p->zStack[i]);
  p->zStack[i] = 0;
  p->aStack[i].flags &= ~(STK_Str|STK_Dyn|STK_Static|STK_Ephem);
}

/*
** Return TRUE if zNum is a 32-bit signed integer and write
** the value of the integer into *pNum.  If zNum is not an integer
** or is an integer that is too large to be expressed with just 32
** bits, then return false.
**
** Under Linux (RedHat 7.2) this routine is much faster than atoi()
** for converting strings into integers.
*/
static int toInt(const char *zNum, int *pNum){
  int v = 0;
  int neg;
  int i, c;
  if( *zNum=='-' ){
    neg = 1;
    zNum++;
  }else if( *zNum=='+' ){
    neg = 0;
    zNum++;
  }else{
    neg = 0;
  }
  for(i=0; (c=zNum[i])>='0' && c<='9'; i++){
    v = v*10 + c - '0';
  }
  *pNum = neg ? -v : v;
  return c==0 && i>0 && (i<10 || (i==10 && memcmp(zNum,"2147483647",10)<=0));
}

/*
** Convert the given stack entity into a integer if it isn't one
** already.
**
** Any prior string or real representation is invalidated.  
** NULLs are converted into 0.
*/
#define Integerify(P,I) \
    if(((P)->aStack[(I)].flags&STK_Int)==0){ hardIntegerify(P,I); }
static void hardIntegerify(Vdbe *p, int i){
  if( p->aStack[i].flags & STK_Real ){
    p->aStack[i].i = (int)p->aStack[i].r;
    Release(p, i);
  }else if( p->aStack[i].flags & STK_Str ){
    toInt(p->zStack[i], &p->aStack[i].i);
    Release(p, i);
  }else{
    p->aStack[i].i = 0;
  }
  p->aStack[i].flags = STK_Int;
}

/*
** Get a valid Real representation for the given stack element.
**
** Any prior string or integer representation is retained.
** NULLs are converted into 0.0.
*/
#define Realify(P,I) \
    if(((P)->aStack[(I)].flags&STK_Real)==0){ hardRealify(P,I); }
static void hardRealify(Vdbe *p, int i){
  if( p->aStack[i].flags & STK_Str ){
    p->aStack[i].r = atof(p->zStack[i]);
  }else if( p->aStack[i].flags & STK_Int ){
    p->aStack[i].r = p->aStack[i].i;
  }else{
    p->aStack[i].r = 0.0;
  }
  p->aStack[i].flags |= STK_Real;
}

/*
** Pop the stack N times.  Free any memory associated with the
** popped stack elements.
*/
static void PopStack(Vdbe *p, int N){
  assert( N>=0 );
  if( p->zStack==0 ) return;
  assert( p->aStack || sqlite_malloc_failed );
  if( p->aStack==0 ) return;
  while( N-- > 0 ){
    if( p->aStack[p->tos].flags & STK_Dyn ){
      sqliteFree(p->zStack[p->tos]);
    }
    p->aStack[p->tos].flags = 0;
    p->zStack[p->tos] = 0;
    p->tos--;
  }
}

/*
** Here is a macro to handle the common case of popping the stack
** once.  This macro only works from within the sqliteVdbeExec()
** function.
*/
#define POPSTACK \
  assert(p->tos>=0); \
  if( aStack[p->tos].flags & STK_Dyn ) sqliteFree(zStack[p->tos]); \
  p->tos--;

/*
** Delete a keylist
*/
static void KeylistFree(Keylist *p){
  while( p ){
    Keylist *pNext = p->pNext;
    sqliteFree(p);
    p = pNext;
  }
}

/*
** Close a cursor and release all the resources that cursor happens
** to hold.
*/
static void cleanupCursor(Cursor *pCx){
  if( pCx->pCursor ){
    sqliteBtreeCloseCursor(pCx->pCursor);
  }
  if( pCx->pBt ){
    sqliteBtreeClose(pCx->pBt);
  }
  sqliteFree(pCx->pData);
  memset(pCx, 0, sizeof(Cursor));
}

/*
** Close all cursors
*/
static void closeAllCursors(Vdbe *p){
  int i;
  for(i=0; i<p->nCursor; i++){
    cleanupCursor(&p->aCsr[i]);
  }
  sqliteFree(p->aCsr);
  p->aCsr = 0;
  p->nCursor = 0;
}

/*
** Remove any elements that remain on the sorter for the VDBE given.
*/
static void SorterReset(Vdbe *p){
  while( p->pSort ){
    Sorter *pSorter = p->pSort;
    p->pSort = pSorter->pNext;
    sqliteFree(pSorter->zKey);
    sqliteFree(pSorter->pData);
    sqliteFree(pSorter);
  }
}

/*
** Clean up the VM after execution.
**
** This routine will automatically close any cursors, lists, and/or
** sorters that were left open.
*/
static void Cleanup(Vdbe *p){
  int i;
  PopStack(p, p->tos+1);
  closeAllCursors(p);
  if( p->aMem ){
    for(i=0; i<p->nMem; i++){
      if( p->aMem[i].s.flags & STK_Dyn ){
        sqliteFree(p->aMem[i].z);
      }
    }
  }
  sqliteFree(p->aMem);
  p->aMem = 0;
  p->nMem = 0;
  if( p->pList ){
    KeylistFree(p->pList);
    p->pList = 0;
  }
  SorterReset(p);
  if( p->pFile ){
    if( p->pFile!=stdin ) fclose(p->pFile);
    p->pFile = 0;
  }
  if( p->azField ){
    sqliteFree(p->azField);
    p->azField = 0;
  }
  p->nField = 0;
  if( p->zLine ){
    sqliteFree(p->zLine);
    p->zLine = 0;
  }
  p->nLineAlloc = 0;
  AggReset(&p->agg);
  if( p->aSet ){
    for(i=0; i<p->nSet; i++){
      sqliteHashClear(&p->aSet[i].hash);
    }
  }
  sqliteFree(p->aSet);
  p->aSet = 0;
  p->nSet = 0;
  if( p->keylistStack ){
    int ii;
    for(ii = 0; ii < p->keylistStackDepth; ii++){
      KeylistFree(p->keylistStack[ii]);
    }
    sqliteFree(p->keylistStack);
    p->keylistStackDepth = 0;
    p->keylistStack = 0;
  }
  sqliteFree(p->zErrMsg);
  p->zErrMsg = 0;
  p->magic = VDBE_MAGIC_DEAD;
}

/*
** Delete an entire VDBE.
*/
void sqliteVdbeDelete(Vdbe *p){
  int i;
  if( p==0 ) return;
  Cleanup(p);
  if( p->pPrev ){
    p->pPrev->pNext = p->pNext;
  }else{
    assert( p->db->pVdbe==p );
    p->db->pVdbe = p->pNext;
  }
  if( p->pNext ){
    p->pNext->pPrev = p->pPrev;
  }
  p->pPrev = p->pNext = 0;
  if( p->nOpAlloc==0 ){
    p->aOp = 0;
    p->nOp = 0;
  }
  for(i=0; i<p->nOp; i++){
    if( p->aOp[i].p3type==P3_DYNAMIC ){
      sqliteFree(p->aOp[i].p3);
    }
  }
  sqliteFree(p->aOp);
  sqliteFree(p->aLabel);
  sqliteFree(p->aStack);
  sqliteFree(p);
}

/*
** Give a listing of the program in the virtual machine.
**
** The interface is the same as sqliteVdbeExec().  But instead of
** running the code, it invokes the callback once for each instruction.
** This feature is used to implement "EXPLAIN".
*/
int sqliteVdbeList(
  Vdbe *p                   /* The VDBE */
){
  sqlite *db = p->db;
  int i;
  static char *azColumnNames[] = {
     "addr", "opcode", "p1",  "p2",  "p3", 
     "int",  "text",   "int", "int", "text",
     0
  };

  assert( p->popStack==0 );
  assert( p->explain );
  p->azColName = azColumnNames;
  p->azResColumn = p->zStack;
  for(i=0; i<5; i++) p->zStack[i] = p->aStack[i].z;
  p->rc = SQLITE_OK;
  for(i=p->pc; p->rc==SQLITE_OK && i<p->nOp; i++){
    if( db->flags & SQLITE_Interrupt ){
      db->flags &= ~SQLITE_Interrupt;
      if( db->magic!=SQLITE_MAGIC_BUSY ){
        p->rc = SQLITE_MISUSE;
      }else{
        p->rc = SQLITE_INTERRUPT;
      }
      sqliteSetString(&p->zErrMsg, sqlite_error_string(p->rc), 0);
      break;
    }
    sprintf(p->zStack[0],"%d",i);
    sprintf(p->zStack[2],"%d", p->aOp[i].p1);
    sprintf(p->zStack[3],"%d", p->aOp[i].p2);
    if( p->aOp[i].p3type==P3_POINTER ){
      sprintf(p->aStack[4].z, "ptr(%#x)", (int)p->aOp[i].p3);
      p->zStack[4] = p->aStack[4].z;
    }else{
      p->zStack[4] = p->aOp[i].p3;
    }
    p->zStack[1] = sqliteOpcodeNames[p->aOp[i].opcode];
    if( p->xCallback==0 ){
      p->pc = i+1;
      p->azResColumn = p->zStack;
      p->nResColumn = 5;
      return SQLITE_ROW;
    }
    if( sqliteSafetyOff(db) ){
      p->rc = SQLITE_MISUSE;
      break;
    }
    if( p->xCallback(p->pCbArg, 5, p->zStack, p->azColName) ){
      p->rc = SQLITE_ABORT;
    }
    if( sqliteSafetyOn(db) ){