SQLite

**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.169 2004/02/14 23:05:53 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Check to see if the schema for the database needs

    if( !db->aDb[i].inTrans ){
      DbClearProperty(db, i, DB_Cookie);
    }
  }
  pParse->nVar = 0;
}

/*
** This is a fake callback procedure used when sqlite_exec() is
** invoked with a NULL callback pointer.  If we pass a NULL callback
** pointer into sqliteVdbeExec() it will return at every OP_Callback,
** which we do not want it to do.  So we substitute a pointer to this
** procedure in place of the NULL.
*/
static int fakeCallback(void *NotUsed, int n, char **az1, char **az2){
  return 0;
}

/*
** This routine is called after a single SQL statement has been
** parsed and we want to execute the VDBE code to implement 
** that statement.  Prior action routines should have already
** constructed VDBE code to do the work of the SQL statement.
** This routine just has to execute the VDBE code.
**
** Note that if an error occurred, it might be the case that
** no VDBE code was generated.
*/
void sqliteExec(Parse *pParse){
  int rc = SQLITE_OK;
  sqlite *db = pParse->db;
  Vdbe *v = pParse->pVdbe;
  int (*xCallback)(void*,int,char**,char**);

  if( sqlite_malloc_failed ) return;
  xCallback = pParse->xCallback;
  if( xCallback==0 ){
    if( pParse->useCallback ){
      xCallback = fakeCallback;
    }else if( v==0 ){
      v = sqliteGetVdbe(pParse);
      sqliteVdbeAddOp(v, OP_Halt, 0, 0);
    }
  }

  if( v && pParse->nErr==0 ){
    FILE *trace = (db->flags & SQLITE_VdbeTrace)!=0 ? stdout : 0;
    sqliteVdbeTrace(v, trace);
    sqliteVdbeMakeReady(v, pParse->nVar, xCallback, pParse->pArg,
                        pParse->explain);
    if( pParse->useCallback ){
      if( pParse->explain ){
        rc = sqliteVdbeList(v);
        db->next_cookie = db->aDb[0].schema_cookie;
      }else{
        sqliteVdbeExec(v);
      }
      rc = sqliteVdbeFinalize(v, &pParse->zErrMsg);
      if( rc ) pParse->nErr++;
      pParse->pVdbe = 0;
      pParse->rc = rc;
      if( rc ) pParse->nErr++;
    }else{
      pParse->rc = pParse->nErr ? SQLITE_ERROR : SQLITE_DONE;
    }
    pParse->colNamesSet = 0;
  }else if( pParse->useCallback==0 && pParse->rc==SQLITE_OK ){
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;
  pParse->nSet = 0;
  pParse->nAgg = 0;
  pParse->nVar = 0;

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.154 2004/02/14 23:05:53 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** A pointer to this structure is used to communicate information

      return SQLITE_ERROR;
    }
  }
  assert( (db->flags & SQLITE_Initialized)!=0 || db->init.busy );
  if( db->pVdbe==0 ){ db->nChange = 0; }
  memset(&sParse, 0, sizeof(sParse));
  sParse.db = db;
  sParse.useCallback = 0;
  if( db->xTrace ) db->xTrace(db->pTraceArg, zSql);
  sqliteRunParser(&sParse, zSql, pzErrMsg);
  if( sqlite_malloc_failed ){
    sqliteSetString(pzErrMsg, "out of memory", (char*)0);
    sParse.rc = SQLITE_NOMEM;
    sqliteRollbackAll(db);
    sqliteResetInternalSchema(db, 0);

** is returned.
*/
int sqlite_reset(
  sqlite_vm *pVm,            /* The virtual machine to be destroyed */
  char **pzErrMsg            /* OUT: Write error messages here */
){
  int rc = sqliteVdbeReset((Vdbe*)pVm, pzErrMsg);
  sqliteVdbeMakeReady((Vdbe*)pVm, -1, 0, 0, 0);
  sqliteStrRealloc(pzErrMsg);
  return rc;
}

/*
** Return a static string that describes the kind of error specified in the
** argument.

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.109 2004/02/12 18:46:39 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%default_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  if( pParse->zErrMsg==0 ){

// These are extra tokens used by the lexer but never seen by the
// parser.  We put them in a rule so that the parser generator will
// add them to the parse.h output file.
//
%nonassoc END_OF_FILE ILLEGAL SPACE UNCLOSED_STRING COMMENT FUNCTION
          COLUMN AGG_FUNCTION.

// Input is zero or more commands.
input ::= cmdlist.

// A list of commands is zero or more commands
//
cmdlist ::= ecmd.
cmdlist ::= cmdlist ecmd.
ecmd ::= explain cmdx SEMI.
ecmd ::= SEMI.
cmdx ::= cmd.           { sqliteExec(pParse); }
explain ::= EXPLAIN.    { sqliteBeginParse(pParse, 1); }
explain ::= .           { sqliteBeginParse(pParse, 0); }

///////////////////// Begin and end transactions. ////////////////////////////

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.154 2004/02/14 16:31:04 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.

static void generateColumnTypes(
  Parse *pParse,      /* Parser context */
  SrcList *pTabList,  /* List of tables */
  ExprList *pEList    /* Expressions defining the result set */
){
  Vdbe *v = pParse->pVdbe;
  int i, j;
  if( pParse->useCallback && (pParse->db->flags & SQLITE_ReportTypes)==0 ){
    return;
  }
  for(i=0; i<pEList->nExpr; i++){
    Expr *p = pEList->a[i].pExpr;
    char *zType = 0;
    if( p==0 ) continue;
    if( p->op==TK_COLUMN && pTabList ){
      Table *pTab;
      int iCol = p->iColumn;

    sqliteErrorMsg(pParse, "SELECTs to the left and right of %s"
      " do not have the same number of result columns", selectOpName(p->op));
    return 1;
  }

  /* Issue a null callback if that is what the user wants.
  */
  if( eDest==SRT_Callback /* &&
    (pParse->useCallback==0 || (pParse->db->flags & SQLITE_NullCallback)!=0) */
  ){
    sqliteVdbeAddOp(v, OP_NullCallback, p->pEList->nExpr, 0);
  }
  return 0;
}

/*
** Scan through the expression pExpr.  Replace every reference to

  if( pOrderBy ){
    generateSortTail(p, v, pEList->nExpr, eDest, iParm);
  }


  /* Issue a null callback if that is what the user wants.
  */
  if( eDest==SRT_Callback /* &&
    (pParse->useCallback==0 || (pParse->db->flags & SQLITE_NullCallback)!=0) */
  ){
    sqliteVdbeAddOp(v, OP_NullCallback, pEList->nExpr, 0);
  }

  /* If this was a subquery, we have now converted the subquery into a
  ** temporary table.  So delete the subquery structure from the parent
  ** to prevent this subquery from being evaluated again and to force the
  ** the use of the temporary table.

/*
** 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 1.212 2004/02/14 23:05:53 drh Exp $
*/
#include "config.h"
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"

** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
*/
struct Parse {
  sqlite *db;          /* The main database structure */
  int rc;              /* Return code from execution */
  sqlite_callback xCallback;  /* The callback function */
  void *pArg;          /* First argument to the callback function */
  char *zErrMsg;       /* An error message */
  Token sErrToken;     /* The token at which the error occurred */
  Token sFirstToken;   /* The first token parsed */
  Token sLastToken;    /* The last token parsed */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
  u8 explain;          /* True if the EXPLAIN flag is found on the query */
  u8 nameClash;        /* A permanent table name clashes with temp table name */
  u8 useAgg;           /* If true, extract field values from the aggregator
                       ** while generating expressions.  Normally false */
  u8 useCallback;      /* True if callbacks should be used to report results */
  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 nAgg;            /* Number of aggregate expressions */
  int nVar;            /* Number of '?' variables seen in the SQL so far */
  AggExpr *aAgg;       /* An array of aggregate expressions */

*************************************************************************
** An tokenizer for SQL
**
** This file contains C code that splits an SQL input string up into
** individual tokens and sends those tokens one-by-one over to the
** parser for analysis.
**
** $Id: tokenize.c,v 1.67 2004/01/08 02:17:33 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include <stdlib.h>

/*

      *pzErrMsg = pParse->zErrMsg;
    }else{
      sqliteFree(pParse->zErrMsg);
    }
    pParse->zErrMsg = 0;
    if( !nErr ) nErr++;
  }
  if( pParse->pVdbe && (pParse->useCallback || pParse->nErr>0) ){
    sqliteVdbeDelete(pParse->pVdbe);
    pParse->pVdbe = 0;
  }
  if( pParse->pNewTable ){
    sqliteDeleteTable(pParse->db, pParse->pNewTable);
    pParse->pNewTable = 0;
  }

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.263 2004/02/14 17:35:07 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

    }else{
      Stringify(pCol);
      azArgv[i] = pCol->z;
    }
  }
  azArgv[i] = 0;
  p->nCallback++;
  if( p->xCallback==0 ){
    p->azResColumn = azArgv;
    p->nResColumn = pOp->p1;
    p->popStack = pOp->p1;
    p->pc = pc + 1;
    p->pTos = pTos;
    return SQLITE_ROW;
  }
  if( sqliteSafetyOff(db) ) goto abort_due_to_misuse; 
  if( p->xCallback(p->pCbArg, pOp->p1, azArgv, p->azColName)!=0 ){
    rc = SQLITE_ABORT;
  }
  if( sqliteSafetyOn(db) ) goto abort_due_to_misuse;
  popStack(&pTos, pOp->p1);
  assert( pTos>=&p->aStack[-1] );
  if( sqlite_malloc_failed ) goto no_mem;
  break;
}

/* Opcode: NullCallback P1 * *
**
** Invoke the callback function once with the 2nd argument (the
** number of columns) equal to P1 and with the 4th argument (the
** names of the columns) set according to prior OP_ColumnName
** instructions.  This is all like the regular
** OP_Callback or OP_SortCallback opcodes.  But the 3rd argument
** which normally contains a pointer to an array of pointers to
** data is NULL.
**
** The callback is only invoked if there have been no prior calls
** to OP_Callback or OP_SortCallback.
**
** This opcode is used to report the number and names of columns
** in cases where the result set is empty.
*/
case OP_NullCallback: {

  if( p->nCallback==0 && (db->flags & SQLITE_NullCallback)!=0 ){
    if( p->xCallback!=0 ){
      if( sqliteSafetyOff(db) ) goto abort_due_to_misuse; 
      if( p->xCallback(p->pCbArg, pOp->p1, 0, p->azColName)!=0 ){
        rc = SQLITE_ABORT;
      }
      if( sqliteSafetyOn(db) ) goto abort_due_to_misuse;
      if( sqlite_malloc_failed ) goto no_mem;
    }else{
      p->azResColumn = 0;
      p->nResColumn = pOp->p1;
      p->popStack = 0;
      p->pc = pc + 1;
      p->pTos = pTos;

      return SQLITE_ROW;
    }
    p->nCallback++;
  }
  p->nResColumn = pOp->p1;
  break;
}

/* Opcode: Concat P1 P2 P3
**
** Look at the first P1 elements of the stack.  Append them all 
** together with the lowest element first.  Use P3 as a separator.  

** instruction.  Pop this record from the stack and invoke the
** callback on it.
*/
case OP_SortCallback: {
  assert( pTos>=p->aStack );
  assert( pTos->flags & MEM_Str );
  p->nCallback++;
  if( p->xCallback==0 ){
    p->pc = pc+1;
    p->azResColumn = (char**)pTos->z;
    p->nResColumn = pOp->p1;
    p->popStack = 1;
    p->pTos = pTos;
    return SQLITE_ROW;
  }else{
    if( sqliteSafetyOff(db) ) goto abort_due_to_misuse;
    if( p->xCallback(p->pCbArg, pOp->p1, (char**)pTos->z, p->azColName)!=0){
      rc = SQLITE_ABORT;
    }
    if( sqliteSafetyOn(db) ) goto abort_due_to_misuse;
  }
  Release(pTos);
  pTos--;
  if( sqlite_malloc_failed ) goto no_mem;
  break;
}

/* Opcode: SortReset * * *
**
** Remove any elements that remain on the sorter.
*/
case OP_SortReset: {

*************************************************************************
** Header file for the Virtual DataBase Engine (VDBE)
**
** This header defines the interface to the virtual database engine
** or VDBE.  The VDBE implements an abstract machine that runs a
** simple program to access and modify the underlying database.
**
** $Id: vdbe.h,v 1.68 2003/09/06 22:18:08 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines

void sqliteVdbeChangeP2(Vdbe*, int addr, int P2);
void sqliteVdbeChangeP3(Vdbe*, int addr, const char *zP1, int N);
void sqliteVdbeDequoteP3(Vdbe*, int addr);
int sqliteVdbeFindOp(Vdbe*, int, int);
VdbeOp *sqliteVdbeGetOp(Vdbe*, int);
int sqliteVdbeMakeLabel(Vdbe*);
void sqliteVdbeDelete(Vdbe*);
void sqliteVdbeMakeReady(Vdbe*,int,sqlite_callback,void*,int);
int sqliteVdbeExec(Vdbe*);
int sqliteVdbeList(Vdbe*);
int sqliteVdbeFinalize(Vdbe*,char**);
void sqliteVdbeResolveLabel(Vdbe*, int);
int sqliteVdbeCurrentAddr(Vdbe*);
void sqliteVdbeTrace(Vdbe*,FILE*);
void sqliteVdbeCompressSpace(Vdbe*,int);
int sqliteVdbeReset(Vdbe*,char **);
int sqliteVdbeSetVariables(Vdbe*,int,const char**);

#endif

  unsigned uniqueCnt;     /* Used by OP_MakeRecord when P2!=0 */
  int errorAction;        /* Recovery action to do in case of an error */
  int undoTransOnError;   /* If error, either ROLLBACK or COMMIT */
  int inTempTrans;        /* True if temp database is transactioned */
  int returnStack[100];   /* Return address stack for OP_Gosub & OP_Return */
  int returnDepth;        /* Next unused element in returnStack[] */
  int nResColumn;         /* Number of columns in one row of the result set */
  char **azResColumn;                        /* Values for one row of result */ 
  int (*xCallback)(void*,int,char**,char**); /* Callback for SELECT results */
  void *pCbArg;                              /* First argument to xCallback() */
  int popStack;           /* Pop the stack this much on entry to VdbeExec() */
  char *zErrMsg;          /* Error message written here */
  u8 explain;             /* True if EXPLAIN present on SQL command */
};

/*
** The following are allowed values for Vdbe.magic

** 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->zArgv;
  for(i=0; i<5; i++) p->zArgv[i] = p->aStack[i].zShort;


  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), (char*)0);
      break;
    }
    sprintf(p->zArgv[0],"%d",i);
    sprintf(p->zArgv[2],"%d", p->aOp[i].p1);
    sprintf(p->zArgv[3],"%d", p->aOp[i].p2);
    if( p->aOp[i].p3type==P3_POINTER ){
      sprintf(p->aStack[4].zShort, "ptr(%#x)", (int)p->aOp[i].p3);
      p->zArgv[4] = p->aStack[4].zShort;
    }else{
      p->zArgv[4] = p->aOp[i].p3;
    }
    p->zArgv[1] = sqliteOpcodeNames[p->aOp[i].opcode];
    if( p->xCallback==0 ){
      p->pc = i+1;
      p->azResColumn = p->zArgv;
      p->nResColumn = 5;
      return SQLITE_ROW;
    }
    if( sqliteSafetyOff(db) ){
      p->rc = SQLITE_MISUSE;
      break;
    }
    if( p->xCallback(p->pCbArg, 5, p->zArgv, p->azColName) ){
      p->rc = SQLITE_ABORT;
    }
    if( sqliteSafetyOn(db) ){
      p->rc = SQLITE_MISUSE;
    }
  }
  return p->rc==SQLITE_OK ? SQLITE_DONE : SQLITE_ERROR;
}

/*
** 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 sqliteVdbeExec().  
**
** The behavior of sqliteVdbeExec() is influenced by the parameters to
** this routine.  If xCallback is NULL, then sqliteVdbeExec() will return
** with SQLITE_ROW whenever there is a row of the result set ready
** to be delivered.  p->azResColumn will point to the row and 
** p->nResColumn gives the number of columns in the row.  If xCallback
** is not NULL, then the xCallback() routine is invoked to process each
** row in the result set.
*/
void sqliteVdbeMakeReady(
  Vdbe *p,                       /* The VDBE */
  int nVar,                      /* Number of '?' see in the SQL statement */
  sqlite_callback xCallback,     /* Result callback */
  void *pCallbackArg,            /* 1st argument to xCallback() */
  int isExplain                  /* True if the EXPLAIN keywords is present */
){
  int n;

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

  p->pTos = &p->aStack[-1];
  p->pc = 0;
  p->rc = SQLITE_OK;
  p->uniqueCnt = 0;
  p->returnDepth = 0;
  p->errorAction = OE_Abort;
  p->undoTransOnError = 0;
  p->xCallback = xCallback;
  p->pCbArg = pCallbackArg;
  p->popStack =  0;
  p->explain |= isExplain;
  p->magic = VDBE_MAGIC_RUN;
#ifdef VDBE_PROFILE
  {
    int i;
    for(i=0; i<p->nOp; i++){