SQLite

** Boston, MA  02111-1307, USA.
**
** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** $Id: btree.c,v 1.27 2001/09/14 18:54:08 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

  while( pBt->pCursor ){
    sqliteBtreeCloseCursor(pBt->pCursor);
  }
  sqlitepager_close(pBt->pPager);
  sqliteFree(pBt);
  return SQLITE_OK;
}

/*
** Change the number of pages in the cache.
*/
int sqliteBtreeSetCacheSize(Btree *pBt, int mxPage){
  sqlitepager_set_cachesize(pBt->pPager, mxPage);
  return SQLITE_OK;
}

/*
** Get a reference to page1 of the database file.  This will
** also acquire a readlock on that file.
**
** SQLITE_OK is returned on success.  If the file is not a
** well-formed database file, then SQLITE_CORRUPT is returned.

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.
**
** @(#) $Id: btree.h,v 1.13 2001/09/14 18:54:08 drh Exp $
*/
#ifndef _BTREE_H_
#define _BTREE_H_

typedef struct Btree Btree;
typedef struct BtCursor BtCursor;

int sqliteBtreeOpen(const char *zFilename, int mode, int nPg, Btree **ppBtree);
int sqliteBtreeClose(Btree*);
int sqliteBtreeSetCacheSize(Btree*, int);

int sqliteBtreeBeginTrans(Btree*);
int sqliteBtreeCommit(Btree*);
int sqliteBtreeRollback(Btree*);

int sqliteBtreeCreateTable(Btree*, int*);
int sqliteBtreeDropTable(Btree*, int);

**     DROP TABLE
**     CREATE INDEX
**     DROP INDEX
**     creating expressions and ID lists
**     COPY
**     VACUUM
**
** $Id: build.c,v 1.34 2001/09/14 18:54:08 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** 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.

  if( (db->flags & SQLITE_InTrans)==0 ) return;
  v = sqliteGetVdbe(pParse);
  if( v ){
    sqliteVdbeAddOp(v, OP_Rollback, 0, 0, 0, 0);
  }
  db->flags &= ~SQLITE_InTrans;
}

/*
** Interpret the given string as a boolean value.
*/
static int getBoolean(char *z){
  static char *azTrue[] = { "yes", "on", "true" };
  int i;
  if( z[0]==0 ) return 0;
  if( isdigit(z[0]) || (z[0]=='-' && isdigit(z[1])) ){
    return atoi(z);
  }
  for(i=0; i<sizeof(azTrue)/sizeof(azTrue[0]); i++){
    if( sqliteStrICmp(z,azTrue[i])==0 ) return 1;
  }
  return 0;
}

/*
** Process a pragma statement.  
**
** Pragmas are of this form:
**
**      PRAGMA id = value
**
** The identifier might also be a string.  The value is a string, and
** identifier, or a number.  If minusFlag is true, then the value is
** a number that was preceded by a minus sign.
*/
void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
  char *zLeft = 0;
  char *zRight = 0;
  sqlite *db = pParse->db;

  zLeft = sqliteStrNDup(pLeft->z, pLeft->n);
  sqliteDequote(zLeft);
  if( minusFlag ){
    zRight = 0;
    sqliteSetNString(&zRight, "-", 1, pRight->z, pRight->n, 0);
  }else{
    zRight = sqliteStrNDup(pRight->z, pRight->n);
    sqliteDequote(zRight);
  }
 
  if( sqliteStrICmp(zLeft,"cache_size")==0 ){
    int size = atoi(zRight);
    sqliteBtreeSetCacheSize(db->pBe, size);
  }else

  if( sqliteStrICmp(zLeft, "vdbe_trace")==0 ){
    if( getBoolean(zRight) ){
      db->flags |= SQLITE_VdbeTrace;
    }else{
      db->flags &= ~SQLITE_VdbeTrace;
    }
  }else

#ifndef NDEBUG
  if( sqliteStrICmp(zLeft, "parser_trace")==0 ){
    extern void sqliteParserTrace(FILE*, char *);
    if( getBoolean(zRight) ){
      sqliteParserTrace(stdout, "parser: ");
    }else{
      sqliteParserTrace(0, 0);
    }
  }else
#endif

  if( zLeft ) sqliteFree(zLeft);
  if( zRight ) sqliteFree(zRight);
}

*************************************************************************
** This is the implementation of the page cache subsystem.
** 
** The page cache is used to access a database file.  The pager journals
** all writes in order to support rollback.  Locking is used to limit
** access to one or more reader or to one writer.
**
** @(#) $Id: pager.c,v 1.18 2001/09/14 18:54:09 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <assert.h>

  int nRef;                   /* Number of in-memory pages with PgHdr.nRef>0 */
  int mxPage;                 /* Maximum number of pages to hold in cache */
  int nHit, nMiss, nOvfl;     /* Cache hits, missing, and LRU overflows */
  unsigned char state;        /* SQLITE_UNLOCK, _READLOCK or _WRITELOCK */
  unsigned char errMask;      /* One of several kinds of errors */
  unsigned char tempFile;     /* zFilename is a temporary file */
  unsigned char readOnly;     /* True for a read-only database */
  unsigned char needSync;     /* True if an fsync() is needed on the journal */
  unsigned char *aInJournal;  /* One bit for each page in the database file */
  PgHdr *pFirst, *pLast;      /* List of free pages */
  PgHdr *pAll;                /* List of all pages */
  PgHdr *aHash[N_PG_HASH];    /* Hash table to map page number of PgHdr */
};

/*

    if( stat(azDirs[i], &buf) ) continue;
    if( !S_ISDIR(buf.st_mode) ) continue;
    if( access(azDirs[i], 07) ) continue;
    return azDirs[i];
  }
  return 0;
}

/*
** Change the maximum number of in-memory pages that are allowed.
*/
void sqlitepager_set_cachesize(Pager *pPager, int mxPage){
  if( mxPage>10 ){
    pPager->mxPage = mxPage;
  }
}

/*
** Create a new page cache and put a pointer to the page cache in *ppPager.
** The file to be cached need not exist.  The file is not locked until
** the first call to sqlitepager_get() and is only held open until the
** last page is released using sqlitepager_unref().
*/

  pPager->dbSize = -1;
  pPager->nPage = 0;
  pPager->mxPage = mxPage>5 ? mxPage : 10;
  pPager->state = SQLITE_UNLOCK;
  pPager->errMask = 0;
  pPager->tempFile = tempFile;
  pPager->readOnly = readOnly;
  pPager->needSync = 0;
  pPager->pFirst = 0;
  pPager->pLast = 0;
  pPager->nExtra = nExtra;
  memset(pPager->aHash, 0, sizeof(pPager->aHash));
  *ppPager = pPager;
  return SQLITE_OK;
}

      pPg->pPrevAll = 0;
      pPager->pAll = pPg;
      pPager->nPage++;
    }else{
      /* Recycle an older page.  First locate the page to be recycled.
      ** Try to find one that is not dirty and is near the head of
      ** of the free list */
      /* int cnt = pPager->mxPage/2; */
      int cnt = 10;
      pPg = pPager->pFirst;
      while( pPg->dirty && 0<cnt-- && pPg->pNextFree ){
        pPg = pPg->pNextFree;
      }
      if( pPg==0 || pPg->dirty ) pPg = pPager->pFirst;
      assert( pPg->nRef==0 );

      /* If the page to be recycled is dirty, sync the journal and write 
      ** the old page into the database. */
      if( pPg->dirty ){
        int rc;
        assert( pPg->inJournal==1 );
        assert( pPager->state==SQLITE_WRITELOCK );
        if( pPager->needSync ){
          rc = fsync(pPager->jfd);
          if( rc!=0 ){
            rc = sqlitepager_rollback(pPager);
            *ppPage = 0;
            if( rc==SQLITE_OK ) rc = SQLITE_IOERR;
            return rc;
          }
          pPager->needSync = 0;
        }
        pager_seek(pPager->fd, (pPg->pgno-1)*SQLITE_PAGE_SIZE);
        rc = pager_write(pPager->fd, PGHDR_TO_DATA(pPg), SQLITE_PAGE_SIZE);
        if( rc!=SQLITE_OK ){
          rc = sqlitepager_rollback(pPager);
          *ppPage = 0;
          if( rc==SQLITE_OK ) rc = SQLITE_FULL;

    if( pPager->aInJournal==0 ){
      return SQLITE_NOMEM;
    }
    pPager->jfd = open(pPager->zJournal, O_RDWR|O_CREAT, 0644);
    if( pPager->jfd<0 ){
      return SQLITE_CANTOPEN;
    }
    pPager->needSync = 0;
    if( pager_lock(pPager->jfd, 1) ){
      close(pPager->jfd);
      pPager->jfd = -1;
      return SQLITE_BUSY;
    }
    pager_unlock(pPager->fd);
    if( pager_lock(pPager->fd, 1) ){

    if( rc!=SQLITE_OK ){
      sqlitepager_rollback(pPager);
      pPager->errMask |= PAGER_ERR_FULL;
      return rc;
    }
    assert( pPager->aInJournal!=0 );
    pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    pPager->needSync = 1;
  }
  pPg->inJournal = 1;
  if( pPager->dbSize<pPg->pgno ){
    pPager->dbSize = pPg->pgno;
  }
  return rc;
}

    rc = pager_errcode(pPager);
    return rc;
  }
  if( pPager->state!=SQLITE_WRITELOCK ){
    return SQLITE_ERROR;
  }
  assert( pPager->jfd>=0 );
  if( pPager->needSync && fsync(pPager->jfd) ){
    goto commit_abort;
  }
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    if( pPg->dirty==0 ) continue;
    rc = pager_seek(pPager->fd, (pPg->pgno-1)*SQLITE_PAGE_SIZE);
    if( rc!=SQLITE_OK ) goto commit_abort;
    rc = pager_write(pPager->fd, PGHDR_TO_DATA(pPg), SQLITE_PAGE_SIZE);

**   http://www.hwaci.com/drh/
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.9 2001/09/14 18:54:09 drh Exp $
*/

/*
** The size of one page
*/
#define SQLITE_PAGE_SIZE 1024

/*
** The type used to represent a page number.  The first page in a file
** is called page 1.  0 is used to represent "not a page".
*/
typedef unsigned int Pgno;

/*
** Each open file is managed by a separate instance of the "Pager" structure.
*/
typedef struct Pager Pager;

int sqlitepager_open(Pager **ppPager,const char *zFilename,int nPage,int nEx);
void sqlitepager_set_destructor(Pager*, void(*)(void*));
void sqlitepager_set_cachesize(Pager*, int);
int sqlitepager_close(Pager *pPager);
int sqlitepager_get(Pager *pPager, Pgno pgno, void **ppPage);
void *sqlitepager_lookup(Pager *pPager, Pgno pgno);
int sqlitepager_ref(void*);
int sqlitepager_unref(void*);
Pgno sqlitepager_pagenumber(void*);
int sqlitepager_write(void*);

**
*************************************************************************
** 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 1.29 2001/09/14 18:54:09 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%default_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  sqliteSetString(&pParse->zErrMsg,"syntax error",0);
  pParse->sErrToken = TOKEN;
}
%name sqliteParser
%include {

id(A) ::= DESC(X).       {A = X;}
id(A) ::= ASC(X).        {A = X;}
id(A) ::= DELIMITERS(X). {A = X;}
id(A) ::= EXPLAIN(X).    {A = X;}
id(A) ::= VACUUM(X).     {A = X;}
id(A) ::= BEGIN(X).      {A = X;}
id(A) ::= END(X).        {A = X;}
id(A) ::= PRAGMA(X).     {A = X;}
id(A) ::= CLUSTER(X).    {A = X;}
id(A) ::= ID(X).         {A = X;}

// And "ids" is an identifer-or-string.
//
%type ids {Token}
ids(A) ::= id(X).        {A = X;}
ids(A) ::= STRING(X).    {A = X;}

cmd ::= COPY ids(X) FROM ids(Y) USING DELIMITERS STRING(Z).
    {sqliteCopy(pParse,&X,&Y,&Z);}
cmd ::= COPY ids(X) FROM ids(Y).
    {sqliteCopy(pParse,&X,&Y,0);}

cmd ::= VACUUM.                {sqliteVacuum(pParse,0);}
cmd ::= VACUUM ids(X).         {sqliteVacuum(pParse,&X);}

cmd ::= PRAGMA ids(X) EQ ids(Y).         {sqlitePragma(pParse,&X,&Y,0);}
cmd ::= PRAGMA ids(X) EQ ON(Y).          {sqlitePragma(pParse,&X,&Y,0);}
cmd ::= PRAGMA ids(X) EQ plus_num(Y).    {sqlitePragma(pParse,&X,&Y,0);}
cmd ::= PRAGMA ids(X) EQ minus_num(Y).   {sqlitePragma(pParse,&X,&Y,1);}
plus_num(A) ::= plus_opt number(X).   {A = X;}
minus_num(A) ::= MINUS number(X).     {A = X;}
number(A) ::= INTEGER(X).  {A = X;}
number(A) ::= FLOAT(X).    {A = X;}
plus_opt ::= PLUS.
plus_opt ::= .

** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.47 2001/09/14 18:54:09 drh Exp $
*/
#include "sqlite.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

/*
** The maximum number of in-memory pages to use for the main database
** table and for temporary tables.
*/
#define MAX_PAGES   100
#define TEMP_PAGES   25

/*
** The paging system deals with 32-bit integers.
*/
typedef unsigned int u32;

/*

void sqliteExec(Parse*);
Expr *sqliteExpr(int, Expr*, Expr*, Token*);
void sqliteExprSpan(Expr*,Token*,Token*);
Expr *sqliteExprFunction(ExprList*, Token*);
void sqliteExprDelete(Expr*);
ExprList *sqliteExprListAppend(ExprList*,Expr*,Token*);
void sqliteExprListDelete(ExprList*);
void sqlitePragma(Parse*,Token*,Token*,int);
void sqliteCommitInternalChanges(sqlite*);
void sqliteRollbackInternalChanges(sqlite*);
void sqliteStartTable(Parse*,Token*,Token*);
void sqliteAddColumn(Parse*,Token*);
void sqliteAddDefaultValue(Parse*,Token*,int);
void sqliteEndTable(Parse*,Token*);
void sqliteDropTable(Parse*, Token*);

*************************************************************************
** 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 1.21 2001/09/14 18:54:09 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include <stdlib.h>

/*
** All the keywords of the SQL language are stored as in a hash

  { "AND",               0, TK_AND,              0 },
  { "AS",                0, TK_AS,               0 },
  { "ASC",               0, TK_ASC,              0 },
  { "BEGIN",             0, TK_BEGIN,            0 },
  { "BETWEEN",           0, TK_BETWEEN,          0 },
  { "BY",                0, TK_BY,               0 },
  { "CHECK",             0, TK_CHECK,            0 },
  { "CLUSTER",           0, TK_CLUSTER,          0 },
  { "COMMIT",            0, TK_COMMIT,           0 },
  { "CONSTRAINT",        0, TK_CONSTRAINT,       0 },
  { "COPY",              0, TK_COPY,             0 },
  { "CREATE",            0, TK_CREATE,           0 },
  { "DEFAULT",           0, TK_DEFAULT,          0 },
  { "DELETE",            0, TK_DELETE,           0 },
  { "DELIMITERS",        0, TK_DELIMITERS,       0 },

  { "LIKE",              0, TK_LIKE,             0 },
  { "NOT",               0, TK_NOT,              0 },
  { "NOTNULL",           0, TK_NOTNULL,          0 },
  { "NULL",              0, TK_NULL,             0 },
  { "ON",                0, TK_ON,               0 },
  { "OR",                0, TK_OR,               0 },
  { "ORDER",             0, TK_ORDER,            0 },
  { "PRAGMA",            0, TK_PRAGMA,           0 },
  { "PRIMARY",           0, TK_PRIMARY,          0 },
  { "ROLLBACK",          0, TK_ROLLBACK,         0 },
  { "SELECT",            0, TK_SELECT,           0 },
  { "SET",               0, TK_SET,              0 },
  { "TABLE",             0, TK_TABLE,            0 },
  { "TRANSACTION",       0, TK_TRANSACTION,      0 },
  { "UNION",             0, TK_UNION,            0 },

** passed in.  An SQLITE_ status code.
*/
int sqliteRunParser(Parse *pParse, char *zSql, char **pzErrMsg){
  int nErr = 0;
  int i;
  void *pEngine;
  int once = 1;

  extern void *sqliteParserAlloc(void*(*)(int));
  extern void sqliteParserFree(void*, void(*)(void*));
  extern int sqliteParser(void*, int, Token, Parse*);


  pParse->db->flags &= ~SQLITE_Interrupt;
  pParse->rc = SQLITE_OK;
  i = 0;
  sqliteParseInfoReset(pParse);
  pEngine = sqliteParserAlloc((void*(*)(int))malloc);
  if( pEngine==0 ){
    sqliteSetString(pzErrMsg, "out of memory", 0);
    return 1;
  }



  while( sqlite_malloc_failed==0 && nErr==0 && i>=0 && zSql[i]!=0 ){
    int tokenType;
    
    if( (pParse->db->flags & SQLITE_Interrupt)!=0 ){
      pParse->rc = SQLITE_INTERRUPT;
      sqliteSetString(pzErrMsg, "interrupt", 0);
      break;
    }
    pParse->sLastToken.z = &zSql[i];
    pParse->sLastToken.n = sqliteGetToken(&zSql[i], &tokenType);
    i += pParse->sLastToken.n;
    if( once ){
      pParse->sFirstToken = pParse->sLastToken;
      once = 0;
    }
    switch( tokenType ){
      case TK_SPACE:
        break;
      case TK_COMMENT: {


















        break;
      }
      case TK_ILLEGAL:
        sqliteSetNString(pzErrMsg, "unrecognized token: \"", -1, 
           pParse->sLastToken.z, pParse->sLastToken.n, "\"", 1, 0);
        nErr++;
        break;