SQLite

/*
** Code an OP_Once instruction and allocate space for its flag. Return the 
** address of the new instruction.
*/
int sqlite3CodeOnce(Parse *pParse){
  Vdbe *v = sqlite3GetVdbe(pParse);      /* Virtual machine being coded */
  return sqlite3VdbeAddOp1(v, OP_Once, pParse->nOnce++);
}

#ifndef SQLITE_OMIT_SUBQUERY
/*
** Generate code that checks the left-most column of index table iCur to see if
** it contains any NULL entries.  Cause the register at regHasNull to be set
** to a non-NULL value if iCur contains no NULLs.  Cause register regHasNull

#ifdef SQLITE_VDBE_COVERAGE
   0,                         /* xVdbeBranch */
   0,                         /* pVbeBranchArg */
#endif
#ifndef SQLITE_OMIT_BUILTIN_TEST
   0,                         /* xTestCallback */
#endif
   0                          /* bLocaltimeFault */

};

/*
** Hash table for global functions - functions common to all
** database connections.  After initialization, this table is
** read-only.
*/

    ** that demonstrat invariants on well-formed database files.
    */
    case SQLITE_TESTCTRL_NEVER_CORRUPT: {
      sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
      break;
    }











    /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
    **
    ** Set the VDBE coverage callback function to xCallback with context 
    ** pointer ptr.
    */
    case SQLITE_TESTCTRL_VDBE_COVERAGE: {

#define SQLITE_TESTCTRL_ALWAYS                  13
#define SQLITE_TESTCTRL_RESERVE                 14
#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
#define SQLITE_TESTCTRL_ISKEYWORD               16
#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */

#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
#define SQLITE_TESTCTRL_BYTEORDER               22
#define SQLITE_TESTCTRL_ISINIT                  23
#define SQLITE_TESTCTRL_SORTER_MMAP             24
#define SQLITE_TESTCTRL_IMPOSTER                25
#define SQLITE_TESTCTRL_LAST                    25

  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nOnce;           /* Number of OP_Once instructions so far */
  int nOpAlloc;        /* Number of slots allocated for Vdbe.aOp[] */
  int szOpAlloc;       /* Bytes of memory space allocated for Vdbe.aOp[] */
  int iFixedOp;        /* Never back out opcodes iFixedOp-1 or earlier */
  int ckBase;          /* Base register of data during check constraints */
  int iSelfTab;        /* Table of an index whose exprs are being coded */
  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */

  void (*xVdbeBranch)(void*,int iSrcLine,u8 eThis,u8 eMx);  /* Callback */
  void *pVdbeBranchArg;                                     /* 1st argument */
#endif
#ifndef SQLITE_OMIT_BUILTIN_TEST
  int (*xTestCallback)(int);        /* Invoked by sqlite3FaultSim() */
#endif
  int bLocaltimeFault;              /* True to fail localtime() calls */

};

/*
** This macro is used inside of assert() statements to indicate that
** the assert is only valid on a well-formed database.  Instead of:
**
**     assert( X );

    transferParseError(pParse, pSubParse);
    if( db->mallocFailed==0 ){
      pProgram->aOp = sqlite3VdbeTakeOpArray(v, &pProgram->nOp, &pTop->nMaxArg);
    }
    pProgram->nMem = pSubParse->nMem;
    pProgram->nCsr = pSubParse->nTab;
    pProgram->nOnce = pSubParse->nOnce;
    pProgram->token = (void *)pTrigger;
    pPrg->aColmask[0] = pSubParse->oldmask;
    pPrg->aColmask[1] = pSubParse->newmask;
    sqlite3VdbeDelete(v);
  }

  assert( !pSubParse->pAinc       && !pSubParse->pZombieTab );

    pOut->u.i = ~sqlite3VdbeIntValue(pIn1);
  }
  break;
}

/* Opcode: Once P1 P2 * * *
**
** Check the "once" flag number P1. If it is set, jump to instruction P2. 
** Otherwise, set the flag and fall through to the next instruction.
** In other words, this opcode causes all following opcodes up through P2
** (but not including P2) to run just once and to be skipped on subsequent
** times through the loop.
**
** All "once" flags are initially cleared whenever a prepared statement
** first begins to run.
*/
case OP_Once: {             /* jump */
  assert( pOp->p1<p->nOnceFlag );
  VdbeBranchTaken(p->aOnceFlag[pOp->p1]!=0, 2);
  if( p->aOnceFlag[pOp->p1] ){
    goto jump_to_p2;
  }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

    ** variable nMem (and later, VdbeFrame.nChildMem) to this value.
    */
    nMem = pProgram->nMem + pProgram->nCsr;
    assert( nMem>0 );
    if( pProgram->nCsr==0 ) nMem++;
    nByte = ROUND8(sizeof(VdbeFrame))
              + nMem * sizeof(Mem)
              + pProgram->nCsr * sizeof(VdbeCursor *)
              + pProgram->nOnce * sizeof(u8);
    pFrame = sqlite3DbMallocZero(db, nByte);
    if( !pFrame ){
      goto no_mem;
    }
    sqlite3VdbeMemRelease(pRt);
    pRt->flags = MEM_Frame;
    pRt->u.pFrame = pFrame;

    pFrame->v = p;
    pFrame->nChildMem = nMem;
    pFrame->nChildCsr = pProgram->nCsr;
    pFrame->pc = (int)(pOp - aOp);
    pFrame->aMem = p->aMem;
    pFrame->nMem = p->nMem;
    pFrame->apCsr = p->apCsr;
    pFrame->nCursor = p->nCursor;
    pFrame->aOp = p->aOp;
    pFrame->nOp = p->nOp;
    pFrame->token = pProgram->token;
    pFrame->aOnceFlag = p->aOnceFlag;
    pFrame->nOnceFlag = p->nOnceFlag;
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
    pFrame->anExec = p->anExec;
#endif

    pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
    for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
      pMem->flags = MEM_Undefined;

  p->pFrame = pFrame;
  p->aMem = aMem = VdbeFrameMem(pFrame);
  p->nMem = pFrame->nChildMem;
  p->nCursor = (u16)pFrame->nChildCsr;
  p->apCsr = (VdbeCursor **)&aMem[p->nMem];
  p->aOp = aOp = pProgram->aOp;
  p->nOp = pProgram->nOp;
  p->aOnceFlag = (u8 *)&p->apCsr[p->nCursor];
  p->nOnceFlag = pProgram->nOnce;
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  p->anExec = 0;
#endif
  pOp = &aOp[-1];
  memset(p->aOnceFlag, 0, p->nOnceFlag);

  break;
}

/* Opcode: Param P1 P2 * * *
**
** This opcode is only ever present in sub-programs called via the 

  }
  pOut->u.i = sqlite3BtreeMaxPageCount(pBt, newMax);
  break;
}
#endif


/* Opcode: Init * P2 * P4 *
** Synopsis: Start at P2
**
** Programs contain a single instance of this opcode as the very first
** opcode.
**
** If tracing is enabled (by the sqlite3_trace()) interface, then
** the UTF-8 string contained in P4 is emitted on the trace callback.
** Or if P4 is blank, use the string returned by sqlite3_sql().
**
** If P2 is not zero, jump to instruction P2.



*/
case OP_Init: {          /* jump */
  char *zTrace;


  /* If the P4 argument is not NULL, then it must be an SQL comment string.
  ** The "--" string is broken up to prevent false-positives with srcck1.c.
  **
  ** This assert() provides evidence for:
  ** EVIDENCE-OF: R-50676-09860 The callback can compute the same text that
  ** would have been returned by the legacy sqlite3_trace() interface by
  ** using the X argument when X begins with "--" and invoking
  ** sqlite3_expanded_sql(P) otherwise.
  */
  assert( pOp->p4.z==0 || strncmp(pOp->p4.z, "-" "- ", 3)==0 );


#ifndef SQLITE_OMIT_TRACE
  if( (db->mTrace & (SQLITE_TRACE_STMT|SQLITE_TRACE_LEGACY))!=0
   && !p->doingRerun
   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
#ifndef SQLITE_OMIT_DEPRECATED

   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
    sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
  }
#endif /* SQLITE_DEBUG */
#endif /* SQLITE_OMIT_TRACE */
  assert( pOp->p2>0 );







  goto jump_to_p2;
}

#ifdef SQLITE_ENABLE_CURSOR_HINTS
/* Opcode: CursorHint P1 * * P4 *
**
** Provide a hint to cursor P1 that it only needs to return rows that

** A sub-routine used to implement a trigger program.
*/
struct SubProgram {
  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
  int nOp;                      /* Elements in aOp[] */
  int nMem;                     /* Number of memory cells required */
  int nCsr;                     /* Number of cursors required */
  int nOnce;                    /* Number of OP_Once instructions */
  void *token;                  /* id that may be used to recursive triggers */
  SubProgram *pNext;            /* Next sub-program already visited */
};

/*
** A smaller version of VdbeOp used for the VdbeAddOpList() function because
** it takes up less space.

typedef struct VdbeFrame VdbeFrame;
struct VdbeFrame {
  Vdbe *v;                /* VM this frame belongs to */
  VdbeFrame *pParent;     /* Parent of this frame, or NULL if parent is main */
  Op *aOp;                /* Program instructions for parent frame */
  i64 *anExec;            /* Event counters from parent frame */
  Mem *aMem;              /* Array of memory cells for parent frame */
  u8 *aOnceFlag;          /* Array of OP_Once flags for parent frame */
  VdbeCursor **apCsr;     /* Array of Vdbe cursors for parent frame */
  void *token;            /* Copy of SubProgram.token */
  i64 lastRowid;          /* Last insert rowid (sqlite3.lastRowid) */
  AuxData *pAuxData;      /* Linked list of auxdata allocations */
  int nCursor;            /* Number of entries in apCsr */
  int pc;                 /* Program Counter in parent (calling) frame */
  int nOp;                /* Size of aOp array */
  int nMem;               /* Number of entries in aMem */
  int nOnceFlag;          /* Number of entries in aOnceFlag */
  int nChildMem;          /* Number of memory cells for child frame */
  int nChildCsr;          /* Number of cursors for child frame */
  int nChange;            /* Statement changes (Vdbe.nChange)     */
  int nDbChange;          /* Value of db->nChange */
};

#define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))])

  char *zSql;             /* Text of the SQL statement that generated this */
  void *pFree;            /* Free this when deleting the vdbe */
  VdbeFrame *pFrame;      /* Parent frame */
  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */
  int nFrame;             /* Number of frames in pFrame list */
  u32 expmask;            /* Binding to these vars invalidates VM */
  SubProgram *pProgram;   /* Linked list of all sub-programs used by VM */
  int nOnceFlag;          /* Size of array aOnceFlag[] */
  u8 *aOnceFlag;          /* Flags for OP_Once */
  AuxData *pAuxData;      /* Linked list of auxdata allocations */
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  i64 *anExec;            /* Number of times each op has been executed */
  int nScan;              /* Entries in aScan[] */
  ScanStatus *aScan;      /* Scan definitions for sqlite3_stmt_scanstatus() */
#endif
};

  Parse *pParse                  /* Parsing context */
){
  sqlite3 *db;                   /* The database connection */
  int nVar;                      /* Number of parameters */
  int nMem;                      /* Number of VM memory registers */
  int nCursor;                   /* Number of cursors required */
  int nArg;                      /* Number of arguments in subprograms */
  int nOnce;                     /* Number of OP_Once instructions */
  int n;                         /* Loop counter */
  struct ReusableSpace x;        /* Reusable bulk memory */

  assert( p!=0 );
  assert( p->nOp>0 );
  assert( pParse!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );
  assert( pParse==p->pParse );
  db = p->db;
  assert( db->mallocFailed==0 );
  nVar = pParse->nVar;
  nMem = pParse->nMem;
  nCursor = pParse->nTab;
  nArg = pParse->nMaxArg;
  nOnce = pParse->nOnce;
  if( nOnce==0 ) nOnce = 1; /* Ensure at least one byte in p->aOnceFlag[] */
  
  /* Each cursor uses a memory cell.  The first cursor (cursor 0) can
  ** use aMem[0] which is not otherwise used by the VDBE program.  Allocate
  ** space at the end of aMem[] for cursors 1 and greater.
  ** See also: allocateCursor().
  */
  nMem += nCursor;

  */
  do {
    x.nNeeded = 0;
    p->aMem = allocSpace(&x, p->aMem, nMem*sizeof(Mem));
    p->aVar = allocSpace(&x, p->aVar, nVar*sizeof(Mem));
    p->apArg = allocSpace(&x, p->apArg, nArg*sizeof(Mem*));
    p->apCsr = allocSpace(&x, p->apCsr, nCursor*sizeof(VdbeCursor*));
    p->aOnceFlag = allocSpace(&x, p->aOnceFlag, nOnce);
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
    p->anExec = allocSpace(&x, p->anExec, p->nOp*sizeof(i64));
#endif
    if( x.nNeeded==0 ) break;
    x.pSpace = p->pFree = sqlite3DbMallocZero(db, x.nNeeded);
    x.nFree = x.nNeeded;
  }while( !db->mallocFailed );

  p->nCursor = nCursor;
  p->nOnceFlag = nOnce;
  if( p->aVar ){
    p->nVar = (ynVar)nVar;
    for(n=0; n<nVar; n++){
      p->aVar[n].flags = MEM_Null;
      p->aVar[n].db = db;
    }
  }

*/
int sqlite3VdbeFrameRestore(VdbeFrame *pFrame){
  Vdbe *v = pFrame->v;
  closeCursorsInFrame(v);
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  v->anExec = pFrame->anExec;
#endif
  v->aOnceFlag = pFrame->aOnceFlag;
  v->nOnceFlag = pFrame->nOnceFlag;
  v->aOp = pFrame->aOp;
  v->nOp = pFrame->nOp;
  v->aMem = pFrame->aMem;
  v->nMem = pFrame->nMem;
  v->apCsr = pFrame->apCsr;
  v->nCursor = pFrame->nCursor;
  v->db->lastRowid = pFrame->lastRowid;

  **     SQLITE_INTERRUPT
  **
  ** Then the internal cache might have been left in an inconsistent
  ** state.  We need to rollback the statement transaction, if there is
  ** one, or the complete transaction if there is no statement transaction.
  */

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