SQLite

/*
** 2003 April 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 to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.84 2009/04/08 13:51:51 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_ATTACH
/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple

  return 0;
}
int sqlite3FixExpr(
  DbFixer *pFix,     /* Context of the fixation */
  Expr *pExpr        /* The expression to be fixed to one database */
){
  while( pExpr ){
    if( ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_SpanToken) ) break;
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      if( sqlite3FixSelect(pFix, pExpr->x.pSelect) ) return 1;
    }else{
      if( sqlite3FixExprList(pFix, pExpr->x.pList) ) return 1;
    }
    if( sqlite3FixExpr(pFix, pExpr->pRight) ){
      return 1;

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.528 2009/04/08 13:51:51 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
*/

          pCol->zName);
    }else{
      /* A copy of pExpr is used instead of the original, as pExpr contains
      ** tokens that point to volatile memory. The 'span' of the expression
      ** is required by pragma table_info.
      */
      sqlite3ExprDelete(db, pCol->pDflt);
      pCol->pDflt = sqlite3ExprDup(db, pExpr, EXPRDUP_REDUCE|EXPRDUP_SPAN);


    }
  }
  sqlite3ExprDelete(db, pExpr);
}

/*
** Designate the PRIMARY KEY for the table.  pList is a list of names 

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.426 2009/04/08 13:51:51 drh Exp $
*/
#include "sqliteInt.h"

/*
** Return the 'affinity' of the expression pExpr if any.
**
** If pExpr is a column, a reference to a column via an 'AS' alias,

/*
** Clear an expression structure without deleting the structure itself.
** Substructure is deleted.
*/
void sqlite3ExprClear(sqlite3 *db, Expr *p){
  if( p->token.dyn ) sqlite3DbFree(db, (char*)p->token.z);
  if( !ExprHasAnyProperty(p, EP_TokenOnly|EP_SpanToken) ){
    if( p->span.dyn ) sqlite3DbFree(db, (char*)p->span.z);
    if( ExprHasProperty(p, EP_Reduced) ){
      /* Subtrees are part of the same memory allocation when EP_Reduced set */
      if( p->pLeft ) sqlite3ExprClear(db, p->pLeft);
      if( p->pRight ) sqlite3ExprClear(db, p->pRight);
    }else{
      /* Subtrees are separate allocations when EP_Reduced is clear */
      sqlite3ExprDelete(db, p->pLeft);
      sqlite3ExprDelete(db, p->pRight);
    }
    /* x.pSelect and x.pList are always separately allocated */
    if( ExprHasProperty(p, EP_xIsSelect) ){
      sqlite3SelectDelete(db, p->x.pSelect);
    }else{
      sqlite3ExprListDelete(db, p->x.pList);
    }
  }
}

/*
** Return the number of bytes allocated for the expression structure 
** passed as the first argument. This is always one of EXPR_FULLSIZE,
** EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
*/
static int exprStructSize(Expr *p){
  if( ExprHasProperty(p, EP_TokenOnly) ) return EXPR_TOKENONLYSIZE;
  if( ExprHasProperty(p, EP_SpanToken) ) return EXPR_SPANTOKENSIZE;
  if( ExprHasProperty(p, EP_Reduced) ) return EXPR_REDUCEDSIZE;
  return EXPR_FULLSIZE;
}

/*
** sqlite3ExprDup() has been called to create a copy of expression p with
** the EXPRDUP_XXX flags passed as the second argument. This function 
** returns the space required for the copy of the Expr structure only.
** This is always one of EXPR_FULLSIZE, EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
*/
static int dupedExprStructSize(Expr *p, int flags){
  int nSize;
  if( 0==(flags&EXPRDUP_REDUCE) ){
    nSize = EXPR_FULLSIZE;
  }else if( p->pLeft || p->pRight || p->pColl || p->x.pList ){
    nSize = EXPR_REDUCEDSIZE;
  }else if( flags&EXPRDUP_SPAN ){
    nSize = EXPR_SPANTOKENSIZE;
  }else{
    nSize = EXPR_TOKENONLYSIZE;
  }
  return nSize;
}

/*
** sqlite3ExprDup() has been called to create a copy of expression p with
** the EXPRDUP_XXX passed as the second argument. This function returns
** the space in bytes required to store the copy of the Expr structure
** and the copies of the Expr.token.z and Expr.span.z (if applicable)
** string buffers.
*/
static int dupedExprNodeSize(Expr *p, int flags){
  int nByte = dupedExprStructSize(p, flags) + (p->token.z ? p->token.n + 1 : 0);
  if( (flags&EXPRDUP_SPAN)!=0
   && (p->token.z!=p->span.z || p->token.n!=p->span.n)
  ){
    nByte += p->span.n;
  }
  return ROUND8(nByte);
}

/*

** descended from the Expr.x.pList or Expr.x.pSelect variables).
*/
static int dupedExprSize(Expr *p, int flags){
  int nByte = 0;
  if( p ){
    nByte = dupedExprNodeSize(p, flags);
    if( flags&EXPRDUP_REDUCE ){
      int f = flags&(~EXPRDUP_SPAN);
      nByte += dupedExprSize(p->pLeft, f) + dupedExprSize(p->pRight, f);
    }
  }
  return nByte;
}

/*
** This function is similar to sqlite3ExprDup(), except that if pzBuffer 
** is not NULL then *pzBuffer is assumed to point to a buffer large enough 
** to store the copy of expression p, the copies of p->token and p->span 
** (if applicable), and the copies of the p->pLeft and p->pRight expressions,
** if any. Before returning, *pzBuffer is set to the first byte passed the
** portion of the buffer copied into by this function.
*/
static Expr *exprDup(sqlite3 *db, Expr *p, int flags, u8 **pzBuffer){
  Expr *pNew = 0;                      /* Value to return */
  if( p ){

    const int isRequireSpan = (flags&EXPRDUP_SPAN);
    const int isReduced = (flags&EXPRDUP_REDUCE);
    u8 *zAlloc;

    assert( pzBuffer==0 || isReduced );

    /* Figure out where to write the new Expr structure. */
    if( pzBuffer ){

      }else{
        int nSize = exprStructSize(p);
        memcpy(zAlloc, p, nSize);
        memset(&zAlloc[nSize], 0, EXPR_FULLSIZE-nSize);
      }

      /* Set the EP_Reduced and EP_TokenOnly flags appropriately. */
      pNew->flags &= ~(EP_Reduced|EP_TokenOnly|EP_SpanToken);
      switch( nNewSize ){
        case EXPR_REDUCEDSIZE:   pNew->flags |= EP_Reduced; break;
        case EXPR_TOKENONLYSIZE: pNew->flags |= EP_TokenOnly; break;
        case EXPR_SPANTOKENSIZE: pNew->flags |= EP_SpanToken; break;
      }

      /* Copy the p->token string, if any. */
      if( nToken ){
        unsigned char *zToken = &zAlloc[nNewSize];
        memcpy(zToken, p->token.z, nToken-1);
        zToken[nToken-1] = '\0';
        pNew->token.dyn = 0;
        pNew->token.z = zToken;
      }

      if( 0==((p->flags|pNew->flags) & EP_TokenOnly) ){
        /* Fill in the pNew->span token, if required. */
        if( isRequireSpan ){

          if( p->token.z!=p->span.z || p->token.n!=p->span.n ){

            pNew->span.z = &zAlloc[nNewSize+nToken];
            memcpy((char *)pNew->span.z, p->span.z, p->span.n);
            pNew->span.dyn = 0;
          }else{
            pNew->span.z = pNew->token.z;
            pNew->span.n = pNew->token.n;
          }
        }else{
          pNew->span.z = 0;
          pNew->span.n = 0;
        }
      }

      if( 0==((p->flags|pNew->flags) & (EP_TokenOnly|EP_SpanToken)) ){
        /* Fill in the pNew->x.pSelect or pNew->x.pList member. */
        if( ExprHasProperty(p, EP_xIsSelect) ){
          pNew->x.pSelect = sqlite3SelectDup(db, p->x.pSelect, isReduced);
        }else{
          pNew->x.pList = sqlite3ExprListDup(db, p->x.pList, isReduced);
        }
      }

      /* Fill in pNew->pLeft and pNew->pRight. */
      if( ExprHasAnyProperty(pNew, EP_Reduced|EP_TokenOnly|EP_SpanToken) ){
        zAlloc += dupedExprNodeSize(p, flags);
        if( ExprHasProperty(pNew, EP_Reduced) ){
          pNew->pLeft = exprDup(db, p->pLeft, EXPRDUP_REDUCE, &zAlloc);
          pNew->pRight = exprDup(db, p->pRight, EXPRDUP_REDUCE, &zAlloc);
        }
        if( pzBuffer ){
          *pzBuffer = zAlloc;
        }
      }else if( !ExprHasAnyProperty(p, EP_TokenOnly|EP_SpanToken) ){
        pNew->pLeft = sqlite3ExprDup(db, p->pLeft, 0);
        pNew->pRight = sqlite3ExprDup(db, p->pRight, 0);
      }
    }
  }
  return pNew;
}

      }else{
        inReg = pInfo->aFunc[pExpr->iAgg].iMem;
      }
      break;
    }
    case TK_CONST_FUNC:
    case TK_FUNCTION: {
      ExprList *pFarg;       /* List of function arguments */


      int nFarg;             /* Number of function arguments */
      FuncDef *pDef;         /* The function definition object */
      int nId;               /* Length of the function name in bytes */
      const char *zId;       /* The function name */
      int constMask = 0;     /* Mask of function arguments that are constant */
      int i;                 /* Loop counter */
      u8 enc = ENC(db);      /* The text encoding used by this database */
      CollSeq *pColl = 0;    /* A collating sequence */

      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      testcase( op==TK_CONST_FUNC );
      testcase( op==TK_FUNCTION );
      if( ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_SpanToken) ){
        pFarg = 0;
      }else{
        pFarg = pExpr->x.pList;
      }
      nFarg = pFarg ? pFarg->nExpr : 0;
      zId = (char*)pExpr->token.z;
      nId = pExpr->token.n;
      pDef = sqlite3FindFunction(db, zId, nId, nFarg, enc, 0);
      assert( pDef!=0 );
      if( pFarg ){

        r1 = sqlite3GetTempRange(pParse, nFarg);
        sqlite3ExprCodeExprList(pParse, pFarg, r1, 1);
      }else{
        r1 = 0;
      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      /* Possibly overload the function if the first argument is
      ** a virtual table column.
      **
      ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
      ** second argument, not the first, as the argument to test to
      ** see if it is a column in a virtual table.  This is done because
      ** the left operand of infix functions (the operand we want to
      ** control overloading) ends up as the second argument to the
      ** function.  The expression "A glob B" is equivalent to 
      ** "glob(B,A).  We want to use the A in "A glob B" to test
      ** for function overloading.  But we use the B term in "glob(B,A)".
      */
      if( nFarg>=2 && (pExpr->flags & EP_InfixFunc) ){
        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[1].pExpr);
      }else if( nFarg>0 ){
        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[0].pExpr);
      }
#endif
      for(i=0; i<nFarg && i<32; i++){
        if( sqlite3ExprIsConstant(pFarg->a[i].pExpr) ){
          constMask |= (1<<i);
        }
        if( (pDef->flags & SQLITE_FUNC_NEEDCOLL)!=0 && !pColl ){
          pColl = sqlite3ExprCollSeq(pParse, pFarg->a[i].pExpr);
        }
      }
      if( pDef->flags & SQLITE_FUNC_NEEDCOLL ){
        if( !pColl ) pColl = db->pDfltColl; 
        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
      }
      sqlite3VdbeAddOp4(v, OP_Function, constMask, r1, target,
                        (char*)pDef, P4_FUNCDEF);
      sqlite3VdbeChangeP5(v, (u8)nFarg);
      if( nFarg ){
        sqlite3ReleaseTempRange(pParse, r1, nFarg);
      }
      sqlite3ExprCacheAffinityChange(pParse, r1, nFarg);
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS:
    case TK_SELECT: {
      testcase( op==TK_EXISTS );
      testcase( op==TK_SELECT );

/*
** 2001 September 15
**
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.854 2009/04/08 13:51:51 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build

**
** If the Expr is of type OP_Column, and the table it is selecting from
** is a disk table or the "old.*" pseudo-table, then pTab points to the
** corresponding table definition.
**
** ALLOCATION NOTES:
**
** Expr objects can use a lot of memory space in database schema.  To
** help reduce memory requirements, sometimes an Expr object will be
** truncated.  And to reduce the number of memory allocations, sometimes
** two or more Expr objects will be stored in a single memory allocation,
** together with Expr.token and/or Expr.span strings.
**
** If the EP_Reduced, EP_SpanToken, and EP_TokenOnly flags are set when
** an Expr object is truncated.  When EP_Reduced is set, then all
** the child Expr objects in the Expr.pLeft and Expr.pRight subtrees
** are contained within the same memory allocation.  Note, however, that
** the subtrees in Expr.x.pList or Expr.x.pSelect are always separately
** allocated, regardless of whether or not EP_Reduced is set.

*/
struct Expr {
  u8 op;                 /* Operation performed by this node */
  char affinity;         /* The affinity of the column or 0 if not a column */
  VVA_ONLY(u8 vvaFlags;) /* Flags used for VV&A only.  EVVA_* below. */
  u16 flags;             /* Various flags.  EP_* See below */
  Token token;           /* An operand token */

  /* If the EP_TokenOnly flag is set in the Expr.flags mask, then no
  ** space is allocated for the fields below this point. An attempt to
  ** access them will result in a segfault or malfunction. 
  *********************************************************************/

  Token span;            /* Complete text of the expression */

  /* If the EP_SpanToken flag is set in the Expr.flags mask, then no
  ** space is allocated for the fields below this point. An attempt to
  ** access them will result in a segfault or malfunction. 
  *********************************************************************/

  Expr *pLeft;           /* Left subnode */
  Expr *pRight;          /* Right subnode */
  union {

#define EP_AnyAff     0x0200  /* Can take a cached column of any affinity */
#define EP_FixedDest  0x0400  /* Result needed in a specific register */
#define EP_IntValue   0x0800  /* Integer value contained in iTable */
#define EP_xIsSelect  0x1000  /* x.pSelect is valid (otherwise x.pList is) */

#define EP_Reduced    0x2000  /* Expr struct is EXPR_REDUCEDSIZE bytes only */
#define EP_TokenOnly  0x4000  /* Expr struct is EXPR_TOKENONLYSIZE bytes only */
#define EP_SpanToken  0x8000  /* Expr size is EXPR_SPANTOKENSIZE bytes */

/*
** The following are the meanings of bits in the Expr.vvaFlags field.
** This information is only used when SQLite is compiled with
** SQLITE_DEBUG defined.
*/
#ifndef NDEBUG

#define ExprClearProperty(E,P)   (E)->flags&=~(P)

/*
** Macros to determine the number of bytes required by a normal Expr 
** struct, an Expr struct with the EP_Reduced flag set in Expr.flags 
** and an Expr struct with the EP_TokenOnly flag set.
*/
#define EXPR_FULLSIZE           sizeof(Expr)           /* Full size */
#define EXPR_REDUCEDSIZE        offsetof(Expr,iTable)  /* Common features */
#define EXPR_SPANTOKENSIZE      offsetof(Expr,pLeft)   /* Fewer features */
#define EXPR_TOKENONLYSIZE      offsetof(Expr,span)    /* Smallest possible */


/*
** Flags passed to the sqlite3ExprDup() function. See the header comment 
** above sqlite3ExprDup() for details.
*/
#define EXPRDUP_REDUCE         0x0001  /* Used reduced-size Expr nodes */
#define EXPRDUP_SPAN           0x0002  /* Make a copy of Expr.span */


/*
** A list of expressions.  Each expression may optionally have a
** name.  An expr/name combination can be used in several ways, such
** as the list of "expr AS ID" fields following a "SELECT" or in the
** list of "ID = expr" items in an UPDATE.  A list of expressions can
** also be used as the argument to a function, in which case the a.zName

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for walking the parser tree for
** an SQL statement.
**
** $Id: walker.c,v 1.4 2009/04/08 13:51:52 drh Exp $
*/
#include "sqliteInt.h"
#include <stdlib.h>
#include <string.h>


/*

** The return value from this routine is WRC_Abort to abandon the tree walk
** and WRC_Continue to continue.
*/
int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
  int rc;
  if( pExpr==0 ) return WRC_Continue;
  testcase( ExprHasProperty(pExpr, EP_TokenOnly) );
  testcase( ExprHasProperty(pExpr, EP_SpanToken) );
  testcase( ExprHasProperty(pExpr, EP_Reduced) );
  rc = pWalker->xExprCallback(pWalker, pExpr);
  if( rc==WRC_Continue
              && !ExprHasAnyProperty(pExpr,EP_TokenOnly|EP_SpanToken) ){
    if( sqlite3WalkExpr(pWalker, pExpr->pLeft) ) return WRC_Abort;
    if( sqlite3WalkExpr(pWalker, pExpr->pRight) ) return WRC_Abort;
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      if( sqlite3WalkSelect(pWalker, pExpr->x.pSelect) ) return WRC_Abort;
    }else{
      if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
    }