/*

** 2003 September 6

**

** The author disclaims copyright to this source code.  In place of

** a legal notice, here is a blessing:

**

**    May you do good and not evil.

**    May you find forgiveness for yourself and forgive others.

**    May you share freely, never taking more than you give.

**

*************************************************************************

** This file contains code used for creating, destroying, and populating

** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior

** to version 2.8.7, all this code was combined into the vdbe.c source file.

** But that file was getting too big so this subroutines were split out.

**

** $Id: vdbeaux.c,v 1.405 2008/08/02 03:50:39 drh Exp $

*/

#include "sqliteInt.h"

#include <ctype.h>

#include "vdbeInt.h"

/*

** When debugging the code generator in a symbolic debugger, one can

** set the sqlite3VdbeAddopTrace to 1 and all opcodes will be printed

** as they are added to the instruction stream.

*/

#ifdef SQLITE_DEBUG

int sqlite3VdbeAddopTrace = 0;

#endif

/*

** Create a new virtual database engine.

*/

Vdbe *sqlite3VdbeCreate(sqlite3 *db){

  Vdbe *p;

  p = sqlite3DbMallocZero(db, sizeof(Vdbe) );

  if( p==0 ) return 0;

  p->db = db;

  if( db->pVdbe ){

    db->pVdbe->pPrev = p;

  }

  p->pNext = db->pVdbe;

  p->pPrev = 0;

  db->pVdbe = p;

  p->magic = VDBE_MAGIC_INIT;

  return p;

}

/*

** Remember the SQL string for a prepared statement.

*/

void sqlite3VdbeSetSql(Vdbe *p, const char *z, int n){

  if( p==0 ) return;

  assert( p->zSql==0 );

  p->zSql = sqlite3DbStrNDup(p->db, z, n);

}

/*

** Return the SQL associated with a prepared statement

*/

const char *sqlite3_sql(sqlite3_stmt *pStmt){

  return ((Vdbe *)pStmt)->zSql;

}

/*

** Swap all content between two VDBE structures.

*/

void sqlite3VdbeSwap(Vdbe *pA, Vdbe *pB){

  Vdbe tmp, *pTmp;

  char *zTmp;

  int nTmp;

  tmp = *pA;

  *pA = *pB;

  *pB = tmp;

  pTmp = pA->pNext;

  pA->pNext = pB->pNext;

  pB->pNext = pTmp;

  pTmp = pA->pPrev;

  pA->pPrev = pB->pPrev;

  pB->pPrev = pTmp;

  zTmp = pA->zSql;

  pA->zSql = pB->zSql;

  pB->zSql = zTmp;

  nTmp = pA->nSql;

  pA->nSql = pB->nSql;

  pB->nSql = nTmp;

}

#ifdef SQLITE_DEBUG

/*

** Turn tracing on or off

*/

void sqlite3VdbeTrace(Vdbe *p, FILE *trace){

  p->trace = trace;

}

#endif

/*

** Resize the Vdbe.aOp array so that it contains at least N

** elements.

**

** If an out-of-memory error occurs while resizing the array,

** Vdbe.aOp and Vdbe.nOpAlloc remain unchanged (this is so that

** any opcodes already allocated can be correctly deallocated

** along with the rest of the Vdbe).

*/

static void resizeOpArray(Vdbe *p, int N){

  VdbeOp *pNew;

  pNew = sqlite3DbRealloc(p->db, p->aOp, N*sizeof(Op));

  if( pNew ){

    p->nOpAlloc = N;

    p->aOp = pNew;

  }

}

/*

** Add a new instruction to the list of instructions current in the

** VDBE.  Return the address of the new instruction.

**

** Parameters:

**

**    p               Pointer to the VDBE

**

**    op              The opcode for this instruction

**

**    p1, p2, p3      Operands

**

** Use the sqlite3VdbeResolveLabel() function to fix an address and

** the sqlite3VdbeChangeP4() function to change the value of the P4

** operand.

*/

int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){

  int i;

  VdbeOp *pOp;

  i = p->nOp;

  assert( p->magic==VDBE_MAGIC_INIT );

  if( p->nOpAlloc<=i ){

    resizeOpArray(p, p->nOpAlloc ? p->nOpAlloc*2 : 1024/sizeof(Op));

    if( p->db->mallocFailed ){

      return 0;

    }

  }

  p->nOp++;

  pOp = &p->aOp[i];

  pOp->opcode = op;

  pOp->p5 = 0;

  pOp->p1 = p1;

  pOp->p2 = p2;

  pOp->p3 = p3;

  pOp->p4.p = 0;

  pOp->p4type = P4_NOTUSED;

  p->expired = 0;

#ifdef SQLITE_DEBUG

  pOp->zComment = 0;

  if( sqlite3VdbeAddopTrace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);

#endif

#ifdef VDBE_PROFILE

  pOp->cycles = 0;

  pOp->cnt = 0;

#endif

  return i;

}

int sqlite3VdbeAddOp0(Vdbe *p, int op){

  return sqlite3VdbeAddOp3(p, op, 0, 0, 0);

}

int sqlite3VdbeAddOp1(Vdbe *p, int op, int p1){

  return sqlite3VdbeAddOp3(p, op, p1, 0, 0);

}

int sqlite3VdbeAddOp2(Vdbe *p, int op, int p1, int p2){

  return sqlite3VdbeAddOp3(p, op, p1, p2, 0);

}

/*

** Add an opcode that includes the p4 value as a pointer.

*/

int sqlite3VdbeAddOp4(

  Vdbe *p,            /* Add the opcode to this VM */

  int op,             /* The new opcode */

  int p1,             /* The P1 operand */

  int p2,             /* The P2 operand */

  int p3,             /* The P3 operand */

  const char *zP4,    /* The P4 operand */

  int p4type          /* P4 operand type */

){

  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);

  sqlite3VdbeChangeP4(p, addr, zP4, p4type);

  return addr;

}

/*

** Create a new symbolic label for an instruction that has yet to be

** coded.  The symbolic label is really just a negative number.  The

** label can be used as the P2 value of an operation.  Later, when

** the label is resolved to a specific address, the VDBE will scan

** through its operation list and change all values of P2 which match

** the label into the resolved address.

**

** The VDBE knows that a P2 value is a label because labels are

** always negative and P2 values are suppose to be non-negative.

** Hence, a negative P2 value is a label that has yet to be resolved.

**

** Zero is returned if a malloc() fails.

*/

int sqlite3VdbeMakeLabel(Vdbe *p){

  int i;

  i = p->nLabel++;

  assert( p->magic==VDBE_MAGIC_INIT );

  if( i>=p->nLabelAlloc ){

    p->nLabelAlloc = p->nLabelAlloc*2 + 10;

    p->aLabel = sqlite3DbReallocOrFree(p->db, p->aLabel,

                                    p->nLabelAlloc*sizeof(p->aLabel[0]));

  }

  if( p->aLabel ){

    p->aLabel[i] = -1;

  }

  return -1-i;

}

/*

** Resolve label "x" to be the address of the next instruction to

** be inserted.  The parameter "x" must have been obtained from

** a prior call to sqlite3VdbeMakeLabel().

*/

void sqlite3VdbeResolveLabel(Vdbe *p, int x){

  int j = -1-x;

  assert( p->magic==VDBE_MAGIC_INIT );

  assert( j>=0 && j<p->nLabel );

  if( p->aLabel ){

    p->aLabel[j] = p->nOp;

  }

}

/*

** Loop through the program looking for P2 values that are negative

** on jump instructions.  Each such value is a label.  Resolve the

** label by setting the P2 value to its correct non-zero value.

**

** This routine is called once after all opcodes have been inserted.

**

** Variable *pMaxFuncArgs is set to the maximum value of any P2 argument 

** to an OP_Function, OP_AggStep or OP_VFilter opcode. This is used by 

** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.

**

** This routine also does the following optimization:  It scans for

** instructions that might cause a statement rollback.  Such instructions

** are:

**

**   *  OP_Halt with P1=SQLITE_CONSTRAINT and P2=OE_Abort.

**   *  OP_Destroy

**   *  OP_VUpdate

**   *  OP_VRename

**

** If no such instruction is found, then every Statement instruction 

** is changed to a Noop.  In this way, we avoid creating the statement 

** journal file unnecessarily.

*/

static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){

  int i;

  int nMaxArgs = 0;

  Op *pOp;

  int *aLabel = p->aLabel;

  int doesStatementRollback = 0;

  int hasStatementBegin = 0;

  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){

    u8 opcode = pOp->opcode;

    if( opcode==OP_Function || opcode==OP_AggStep ){

      if( pOp->p5>nMaxArgs ) nMaxArgs = pOp->p5;

#ifndef SQLITE_OMIT_VIRTUALTABLE

    }else if( opcode==OP_VUpdate ){

      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;

#endif

    }

    if( opcode==OP_Halt ){

      if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){

        doesStatementRollback = 1;

      }

    }else if( opcode==OP_Statement ){

      hasStatementBegin = 1;

    }else if( opcode==OP_Destroy ){

      doesStatementRollback = 1;

#ifndef SQLITE_OMIT_VIRTUALTABLE

    }else if( opcode==OP_VUpdate || opcode==OP_VRename ){

      doesStatementRollback = 1;

    }else if( opcode==OP_VFilter ){

      int n;

      assert( p->nOp - i >= 3 );

      assert( pOp[-1].opcode==OP_Integer );

      n = pOp[-1].p1;

      if( n>nMaxArgs ) nMaxArgs = n;

#endif

    }

    if( sqlite3VdbeOpcodeHasProperty(opcode, OPFLG_JUMP) && pOp->p2<0 ){

      assert( -1-pOp->p2<p->nLabel );

      pOp->p2 = aLabel[-1-pOp->p2];

    }

  }

  sqlite3DbFree(p->db, p->aLabel);

  p->aLabel = 0;

  *pMaxFuncArgs = nMaxArgs;

  /* If we never rollback a statement transaction, then statement

  ** transactions are not needed.  So change every OP_Statement

  ** opcode into an OP_Noop.  This avoid a call to sqlite3OsOpenExclusive()

  ** which can be expensive on some platforms.

  */

  if( hasStatementBegin && !doesStatementRollback ){

    for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){

      if( pOp->opcode==OP_Statement ){

        pOp->opcode = OP_Noop;

      }

    }

  }

}

/*

** Return the address of the next instruction to be inserted.

*/

int sqlite3VdbeCurrentAddr(Vdbe *p){

  assert( p->magic==VDBE_MAGIC_INIT );

  return p->nOp;

}

/*

** Add a whole list of operations to the operation stack.  Return the

** address of the first operation added.

*/

int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp){

  int addr;

  assert( p->magic==VDBE_MAGIC_INIT );

  if( p->nOp + nOp > p->nOpAlloc ){

    resizeOpArray(p, p->nOpAlloc ? p->nOpAlloc*2 : 1024/sizeof(Op));

    assert( p->nOp+nOp<=p->nOpAlloc || p->db->mallocFailed );

  }

  if( p->db->mallocFailed ){

    return 0;

  }

  addr = p->nOp;

  if( nOp>0 ){

    int i;

    VdbeOpList const *pIn = aOp;

    for(i=0; i<nOp; i++, pIn++){

      int p2 = pIn->p2;

      VdbeOp *pOut = &p->aOp[i+addr];

      pOut->opcode = pIn->opcode;

      pOut->p1 = pIn->p1;

      if( p2<0 && sqlite3VdbeOpcodeHasProperty(pOut->opcode, OPFLG_JUMP) ){

        pOut->p2 = addr + ADDR(p2);

      }else{

        pOut->p2 = p2;

      }

      pOut->p3 = pIn->p3;

      pOut->p4type = P4_NOTUSED;

      pOut->p4.p = 0;

      pOut->p5 = 0;

#ifdef SQLITE_DEBUG

      pOut->zComment = 0;

      if( sqlite3VdbeAddopTrace ){

        sqlite3VdbePrintOp(0, i+addr, &p->aOp[i+addr]);

      }

#endif

    }

    p->nOp += nOp;

  }

  return addr;

}

/*

** Change the value of the P1 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.

*/

void sqlite3VdbeChangeP1(Vdbe *p, int addr, int val){

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

  if( p && addr>=0 && p->nOp>addr && p->aOp ){

    p->aOp[addr].p1 = val;

  }

}

/*

** Change the value of the P2 operand for a specific instruction.

** This routine is useful for setting a jump destination.

*/

void sqlite3VdbeChangeP2(Vdbe *p, int addr, int val){

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

  if( p && addr>=0 && p->nOp>addr && p->aOp ){

    p->aOp[addr].p2 = val;

  }

}

/*

** Change the value of the P3 operand for a specific instruction.

*/

void sqlite3VdbeChangeP3(Vdbe *p, int addr, int val){

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

  if( p && addr>=0 && p->nOp>addr && p->aOp ){

    p->aOp[addr].p3 = val;

  }

}

/*

** Change the value of the P5 operand for the most recently

** added operation.

*/

void sqlite3VdbeChangeP5(Vdbe *p, u8 val){

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

  if( p && p->aOp ){

    assert( p->nOp>0 );

    p->aOp[p->nOp-1].p5 = val;

  }

}

/*

** Change the P2 operand of instruction addr so that it points to

** the address of the next instruction to be coded.

*/

void sqlite3VdbeJumpHere(Vdbe *p, int addr){

  sqlite3VdbeChangeP2(p, addr, p->nOp);

}

/*

** If the input FuncDef structure is ephemeral, then free it.  If

** the FuncDef is not ephermal, then do nothing.

*/

static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){

  if( pDef && (pDef->flags & SQLITE_FUNC_EPHEM)!=0 ){

    sqlite3DbFree(db, pDef);

  }

}

/*

** Delete a P4 value if necessary.

*/

static void freeP4(sqlite3 *db, int p4type, void *p4){

  if( p4 ){

    switch( p4type ){

      case P4_REAL:

      case P4_INT64:

      case P4_MPRINTF:

      case P4_DYNAMIC:

      case P4_KEYINFO:

      case P4_INTARRAY:

      case P4_KEYINFO_HANDOFF: {

        sqlite3DbFree(db, p4);

        break;

      }

      case P4_VDBEFUNC: {

        VdbeFunc *pVdbeFunc = (VdbeFunc *)p4;

        freeEphemeralFunction(db, pVdbeFunc->pFunc);

        sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);

        sqlite3DbFree(db, pVdbeFunc);

        break;

      }

      case P4_FUNCDEF: {

        freeEphemeralFunction(db, (FuncDef*)p4);

        break;

      }

      case P4_MEM: {

        sqlite3ValueFree((sqlite3_value*)p4);

        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];

    sqlite3 *db = p->db;

    while( N-- ){

      freeP4(db, pOp->p4type, pOp->p4.p);

      memset(pOp, 0, sizeof(pOp[0]));

      pOp->opcode = OP_Noop;

      pOp++;

    }

  }

}

/*

** Change the value of the P4 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 P4 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 zP4 up to and including the

** first null byte.  If n>0 then copy n+1 bytes of zP4.

**

** If n==P4_KEYINFO it means that zP4 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==P4_KEYINFO_HANDOFF indicates that zP4 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 (P4_STATIC, P4_COLLSEQ etc.) indicate that zP4 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 P4 on the most recently inserted instruction.

*/

void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int n){

  Op *pOp;

  sqlite3 *db;

  assert( p!=0 );

  db = p->db;

  assert( p->magic==VDBE_MAGIC_INIT );

  if( p->aOp==0 || db->mallocFailed ){

    if (n != P4_KEYINFO) {

      freeP4(db, n, (void*)*(char**)&zP4);

    }

    return;

  }