** 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.
**
*************************************************************************
** $Id: btree.c,v 1.72 2002/09/01 23:20:45 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.
................................................................................
**
** The pParent parameter must be a pointer to the MemPage which
** is the parent of the page being initialized.  The root of the
** BTree (usually page 2) has no parent and so for that page, 
** pParent==NULL.
**
** Return SQLITE_OK on success.  If we see that the page does
** not contained a well-formed database page, then return 
** SQLITE_CORRUPT.  Note that a return of SQLITE_OK does not
** guarantee that the page is well-formed.  It only shows that
** we failed to detect any corruption.
*/
static int initPage(Bt *pBt, MemPage *pPage, Pgno pgnoThis, MemPage *pParent){
  int idx;           /* An index into pPage->u.aDisk[] */
  Cell *pCell;       /* A pointer to a Cell in pPage->u.aDisk[] */
................................................................................
**
** zFilename is the name of the database file.  If zFilename is NULL
** a new database with a random name is created.  This randomly named
** database file will be deleted when sqliteBtreeClose() is called.
*/
int sqliteBtreeOpen(
  const char *zFilename,    /* Name of the file containing the BTree database */
  int mode,                 /* Not currently used */
  int nCache,               /* How many pages in the page cache */
  Btree **ppBtree           /* Pointer to new Btree object written here */
){
  Btree *pBt;
  int rc;

  pBt = sqliteMalloc( sizeof(*pBt) );
  if( pBt==0 ){
    *ppBtree = 0;
    return SQLITE_NOMEM;
  }
  if( nCache<10 ) nCache = 10;
  rc = sqlitepager_open(&pBt->pPager, zFilename, nCache, EXTRA_SIZE);

  if( rc!=SQLITE_OK ){
    if( pBt->pPager ) sqlitepager_close(pBt->pPager);
    sqliteFree(pBt);
    *ppBtree = 0;
    return rc;
  }
  sqlitepager_set_destructor(pBt->pPager, pageDestructor);
................................................................................
  }
  sqlitepager_close(pBt->pPager);
  sqliteFree(pBt);
  return SQLITE_OK;
}

/*
** Change the limit on the number of pages allowed the cache.
**
** The maximum number of cache pages is set to the absolute
** value of mxPage.  If mxPage is negative, the pager will
** operate asynchronously - it will not stop to do fsync()s
** to insure data is written to the disk surface before
** continuing.  Transactions still work if synchronous is off,
** and the database cannot be corrupted if this program
................................................................................
  MemPage *pMemPage;

  if( pgno==0 ){
    assert( pOvfl!=0 );
    pgno = sqlitepager_pagenumber(pOvfl);
  }
  assert( pgno>2 );

  pMemPage = (MemPage*)pPage;
  pMemPage->isInit = 0;
  if( pMemPage->pParent ){
    sqlitepager_unref(pMemPage->pParent);
    pMemPage->pParent = 0;
  }
  rc = sqlitepager_write(pPage1);

** 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.
**
*************************************************************************
** $Id: btree.c,v 1.73 2002/12/02 04:25:20 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.
................................................................................
**
** The pParent parameter must be a pointer to the MemPage which
** is the parent of the page being initialized.  The root of the
** BTree (usually page 2) has no parent and so for that page, 
** pParent==NULL.
**
** Return SQLITE_OK on success.  If we see that the page does
** not contain a well-formed database page, then return 
** SQLITE_CORRUPT.  Note that a return of SQLITE_OK does not
** guarantee that the page is well-formed.  It only shows that
** we failed to detect any corruption.
*/
static int initPage(Bt *pBt, MemPage *pPage, Pgno pgnoThis, MemPage *pParent){
  int idx;           /* An index into pPage->u.aDisk[] */
  Cell *pCell;       /* A pointer to a Cell in pPage->u.aDisk[] */
................................................................................
**
** zFilename is the name of the database file.  If zFilename is NULL
** a new database with a random name is created.  This randomly named
** database file will be deleted when sqliteBtreeClose() is called.
*/
int sqliteBtreeOpen(
  const char *zFilename,    /* Name of the file containing the BTree database */
  int omitJournal,          /* if TRUE then do not journal this file */
  int nCache,               /* How many pages in the page cache */
  Btree **ppBtree           /* Pointer to new Btree object written here */
){
  Btree *pBt;
  int rc;

  pBt = sqliteMalloc( sizeof(*pBt) );
  if( pBt==0 ){
    *ppBtree = 0;
    return SQLITE_NOMEM;
  }
  if( nCache<10 ) nCache = 10;
  rc = sqlitepager_open(&pBt->pPager, zFilename, nCache, EXTRA_SIZE,
                        !omitJournal);
  if( rc!=SQLITE_OK ){
    if( pBt->pPager ) sqlitepager_close(pBt->pPager);
    sqliteFree(pBt);
    *ppBtree = 0;
    return rc;
  }
  sqlitepager_set_destructor(pBt->pPager, pageDestructor);
................................................................................
  }
  sqlitepager_close(pBt->pPager);
  sqliteFree(pBt);
  return SQLITE_OK;
}

/*
** Change the limit on the number of pages allowed in the cache.
**
** The maximum number of cache pages is set to the absolute
** value of mxPage.  If mxPage is negative, the pager will
** operate asynchronously - it will not stop to do fsync()s
** to insure data is written to the disk surface before
** continuing.  Transactions still work if synchronous is off,
** and the database cannot be corrupted if this program
................................................................................
  MemPage *pMemPage;

  if( pgno==0 ){
    assert( pOvfl!=0 );
    pgno = sqlitepager_pagenumber(pOvfl);
  }
  assert( pgno>2 );
  assert( sqlitepager_pagenumber(pOvfl)==pgno );
  pMemPage = (MemPage*)pPage;
  pMemPage->isInit = 0;
  if( pMemPage->pParent ){
    sqlitepager_unref(pMemPage->pParent);
    pMemPage->pParent = 0;
  }
  rc = sqlitepager_write(pPage1);

**     COPY
**     VACUUM
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.115 2002/10/20 16:00:28 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
................................................................................
        { OP_ColumnName,  3, 0,       "notnull"},
        { OP_ColumnName,  4, 0,       "dflt_value"},
      };
      int i;
      sqliteVdbeAddOpList(v, ArraySize(tableInfoPreface), tableInfoPreface);
      sqliteViewGetColumnNames(pParse, pTab);
      for(i=0; i<pTab->nCol; i++){
        char *zType;
        sqliteVdbeAddOp(v, OP_Integer, i, 0);
        sqliteVdbeAddOp(v, OP_String, 0, 0);
        sqliteVdbeChangeP3(v, -1, pTab->aCol[i].zName, P3_STATIC);
        sqliteVdbeAddOp(v, OP_String, 0, 0);
        sqliteVdbeChangeP3(v, -1, 
           pTab->aCol[i].zType ? pTab->aCol[i].zType : "numeric", P3_STATIC);
        sqliteVdbeAddOp(v, OP_Integer, pTab->aCol[i].notNull, 0);

**     COPY
**     VACUUM
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.116 2002/12/02 04:25:21 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
................................................................................
        { OP_ColumnName,  3, 0,       "notnull"},
        { OP_ColumnName,  4, 0,       "dflt_value"},
      };
      int i;
      sqliteVdbeAddOpList(v, ArraySize(tableInfoPreface), tableInfoPreface);
      sqliteViewGetColumnNames(pParse, pTab);
      for(i=0; i<pTab->nCol; i++){

        sqliteVdbeAddOp(v, OP_Integer, i, 0);
        sqliteVdbeAddOp(v, OP_String, 0, 0);
        sqliteVdbeChangeP3(v, -1, pTab->aCol[i].zName, P3_STATIC);
        sqliteVdbeAddOp(v, OP_String, 0, 0);
        sqliteVdbeChangeP3(v, -1, 
           pTab->aCol[i].zType ? pTab->aCol[i].zType : "numeric", P3_STATIC);
        sqliteVdbeAddOp(v, OP_Integer, pTab->aCol[i].notNull, 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 1.104 2002/11/09 00:33:16 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** A pointer to this structure is used to communicate information
................................................................................
  sqliteHashInit(&db->aFunc, SQLITE_HASH_STRING, 1);
  sqliteHashInit(&db->aFKey, SQLITE_HASH_STRING, 1);
  db->onError = OE_Default;
  db->priorNewRowid = 0;
  db->magic = SQLITE_MAGIC_BUSY;
  
  /* Open the backend database driver */
  rc = sqliteBtreeOpen(zFilename, mode, MAX_PAGES, &db->pBe);
  if( rc!=SQLITE_OK ){
    switch( rc ){
      default: {
        sqliteSetString(pzErrMsg, "unable to open database: ", zFilename, 0);
      }
    }
    sqliteFree(db);

**
*************************************************************************
** 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 1.105 2002/12/02 04:25:21 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** A pointer to this structure is used to communicate information
................................................................................
  sqliteHashInit(&db->aFunc, SQLITE_HASH_STRING, 1);
  sqliteHashInit(&db->aFKey, SQLITE_HASH_STRING, 1);
  db->onError = OE_Default;
  db->priorNewRowid = 0;
  db->magic = SQLITE_MAGIC_BUSY;
  
  /* Open the backend database driver */
  rc = sqliteBtreeOpen(zFilename, 0, MAX_PAGES, &db->pBe);
  if( rc!=SQLITE_OK ){
    switch( rc ){
      default: {
        sqliteSetString(pzErrMsg, "unable to open database: ", zFilename, 0);
      }
    }
    sqliteFree(db);

#if OS_WIN
# include <winbase.h>
#endif

/*
** Macros for performance tracing.  Normally turned off
*/
#if 1
static int last_page = 0;
#define SEEK(X)       last_page=(X)
#define TRACE1(X)     fprintf(stderr,X)
#define TRACE2(X,Y)   fprintf(stderr,X,Y)
#define TRACE3(X,Y,Z) fprintf(stderr,X,Y,Z)
#else
#define SEEK(X)
................................................................................
  id->pLock = findLockInfo(id->fd);
  sqliteOsLeaveMutex();
  if( id->pLock==0 ){
    close(id->fd);
    return SQLITE_NOMEM;
  }
  id->locked = 0;

  return SQLITE_OK;
#endif
#if OS_WIN
  HANDLE h = CreateFile(zFilename,
     GENERIC_READ | GENERIC_WRITE,
     FILE_SHARE_READ | FILE_SHARE_WRITE,
     NULL,
................................................................................
    unlink(zFilename);
    return SQLITE_NOMEM;
  }
  id->locked = 0;
  if( delFlag ){
    unlink(zFilename);
  }

  return SQLITE_OK;
#endif
#if OS_WIN
  HANDLE h;
  int fileflags;
  if( delFlag ){
    fileflags = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_RANDOM_ACCESS 
................................................................................
  id->pLock = findLockInfo(id->fd);
  sqliteOsLeaveMutex();
  if( id->pLock==0 ){
    close(id->fd);
    return SQLITE_NOMEM;
  }
  id->locked = 0;

  return SQLITE_OK;
#endif
#if OS_WIN
  HANDLE h = CreateFile(zFilename,
     GENERIC_READ,
     0,
     NULL,
................................................................................
*/
int sqliteOsClose(OsFile *id){
#if OS_UNIX
  close(id->fd);
  sqliteOsEnterMutex();
  releaseLockInfo(id->pLock);
  sqliteOsLeaveMutex();

  return SQLITE_OK;
#endif
#if OS_WIN
  CloseHandle(id->h);
  return SQLITE_OK;
#endif
}
................................................................................
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
int sqliteOsRead(OsFile *id, void *pBuf, int amt){
#if OS_UNIX
  int got;
  SimulateIOError(SQLITE_IOERR);
  TRACE2("READ %d\n", last_page);
  got = read(id->fd, pBuf, amt);
  /* if( got<0 ) got = 0; */
  if( got==amt ){
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR;
  }
................................................................................
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
int sqliteOsWrite(OsFile *id, const void *pBuf, int amt){
#if OS_UNIX
  int wrote = 0;
  SimulateIOError(SQLITE_IOERR);
  TRACE2("WRITE %d\n", last_page);
  while( amt>0 && (wrote = write(id->fd, pBuf, amt))>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
  }
  if( amt>0 ){
    return SQLITE_FULL;
  }
................................................................................
#endif
#if OS_WIN
  {
    LONG upperBits = offset>>32;
    LONG lowerBits = offset & 0xffffffff;
    DWORD rc;
    rc = SetFilePointer(id->h, lowerBits, &upperBits, FILE_BEGIN);
    TRACE3("SEEK rc=0x%x upper=0x%x\n", rc, upperBits);
  }
  return SQLITE_OK;
#endif
}

/*
** Make sure all writes to a particular file are committed to disk.
*/
int sqliteOsSync(OsFile *id){
  SimulateIOError(SQLITE_IOERR);
  TRACE1("SYNC\n");
#if OS_UNIX
  if( fsync(id->fd) ){
    return SQLITE_IOERR;
  }else{
    return SQLITE_OK;
  }
#endif

#if OS_WIN
# include <winbase.h>
#endif

/*
** Macros for performance tracing.  Normally turned off
*/
#if 0
static int last_page = 0;
#define SEEK(X)       last_page=(X)
#define TRACE1(X)     fprintf(stderr,X)
#define TRACE2(X,Y)   fprintf(stderr,X,Y)
#define TRACE3(X,Y,Z) fprintf(stderr,X,Y,Z)
#else
#define SEEK(X)
................................................................................
  id->pLock = findLockInfo(id->fd);
  sqliteOsLeaveMutex();
  if( id->pLock==0 ){
    close(id->fd);
    return SQLITE_NOMEM;
  }
  id->locked = 0;
  TRACE3("OPEN    %-3d %s\n", id->fd, zFilename);
  return SQLITE_OK;
#endif
#if OS_WIN
  HANDLE h = CreateFile(zFilename,
     GENERIC_READ | GENERIC_WRITE,
     FILE_SHARE_READ | FILE_SHARE_WRITE,
     NULL,
................................................................................
    unlink(zFilename);
    return SQLITE_NOMEM;
  }
  id->locked = 0;
  if( delFlag ){
    unlink(zFilename);
  }
  TRACE3("OPEN-EX %-3d %s\n", id->fd, zFilename);
  return SQLITE_OK;
#endif
#if OS_WIN
  HANDLE h;
  int fileflags;
  if( delFlag ){
    fileflags = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_RANDOM_ACCESS 
................................................................................
  id->pLock = findLockInfo(id->fd);
  sqliteOsLeaveMutex();
  if( id->pLock==0 ){
    close(id->fd);
    return SQLITE_NOMEM;
  }
  id->locked = 0;
  TRACE3("OPEN-RO %-3d %s\n", id->fd, zFilename);
  return SQLITE_OK;
#endif
#if OS_WIN
  HANDLE h = CreateFile(zFilename,
     GENERIC_READ,
     0,
     NULL,
................................................................................
*/
int sqliteOsClose(OsFile *id){
#if OS_UNIX
  close(id->fd);
  sqliteOsEnterMutex();
  releaseLockInfo(id->pLock);
  sqliteOsLeaveMutex();
  TRACE2("CLOSE   %-3d\n", id->fd);
  return SQLITE_OK;
#endif
#if OS_WIN
  CloseHandle(id->h);
  return SQLITE_OK;
#endif
}
................................................................................
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
int sqliteOsRead(OsFile *id, void *pBuf, int amt){
#if OS_UNIX
  int got;
  SimulateIOError(SQLITE_IOERR);
  TRACE3("READ    %-3d %d\n", id->fd, last_page);
  got = read(id->fd, pBuf, amt);
  /* if( got<0 ) got = 0; */
  if( got==amt ){
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR;
  }
................................................................................
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
int sqliteOsWrite(OsFile *id, const void *pBuf, int amt){
#if OS_UNIX
  int wrote = 0;
  SimulateIOError(SQLITE_IOERR);
  TRACE3("WRITE   %-3d %d\n", id->fd, last_page);
  while( amt>0 && (wrote = write(id->fd, pBuf, amt))>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
  }
  if( amt>0 ){
    return SQLITE_FULL;
  }
................................................................................
#endif
#if OS_WIN
  {
    LONG upperBits = offset>>32;
    LONG lowerBits = offset & 0xffffffff;
    DWORD rc;
    rc = SetFilePointer(id->h, lowerBits, &upperBits, FILE_BEGIN);
    /* TRACE3("SEEK rc=0x%x upper=0x%x\n", rc, upperBits); */
  }
  return SQLITE_OK;
#endif
}

/*
** Make sure all writes to a particular file are committed to disk.
*/
int sqliteOsSync(OsFile *id){
  SimulateIOError(SQLITE_IOERR);
  TRACE2("SYNC    %-3d\n", id->fd);
#if OS_UNIX
  if( fsync(id->fd) ){
    return SQLITE_IOERR;
  }else{
    return SQLITE_OK;
  }
#endif

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.59 2002/12/01 02:00:58 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
  int nExtra;                 /* Add this many bytes to each in-memory page */
  void (*xDestructor)(void*); /* Call this routine when freeing pages */
  int nPage;                  /* Total number of in-memory pages */
  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 */
  u8 journalOpen;             /* True if journal file descriptors is valid */

  u8 ckptOpen;                /* True if the checkpoint journal is open */
  u8 ckptInUse;               /* True we are in a checkpoint */

  u8 noSync;                  /* Do not sync the journal if true */
  u8 state;                   /* SQLITE_UNLOCK, _READLOCK or _WRITELOCK */
  u8 errMask;                 /* One of several kinds of errors */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 needSync;                /* True if an fsync() is needed on the journal */
  u8 dirtyFile;               /* True if database file has changed in any way */
................................................................................
  PgHdr *pPg;
  if( pPager->state<SQLITE_WRITELOCK ) return SQLITE_OK;
  sqlitepager_ckpt_commit(pPager);
  if( pPager->ckptOpen ){
    sqliteOsClose(&pPager->cpfd);
    pPager->ckptOpen = 0;
  }

  sqliteOsClose(&pPager->jfd);
  pPager->journalOpen = 0;
  sqliteOsDelete(pPager->zJournal);
  rc = sqliteOsReadLock(&pPager->fd);
  sqliteFree( pPager->aInJournal );
  pPager->aInJournal = 0;
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    pPg->inJournal = 0;
    pPg->dirty = 0;
  }




  if( rc==SQLITE_OK ){
    pPager->state = SQLITE_READLOCK;
  }else{
    /* This can only happen if a process does a BEGIN, then forks and the
    ** child process does the COMMIT.  Because of the semantics of unix
    ** file locking, the unlock will fail.
    */
................................................................................
** and used as the file to be cached.  The file will be deleted
** automatically when it is closed.
*/
int sqlitepager_open(
  Pager **ppPager,         /* Return the Pager structure here */
  const char *zFilename,   /* Name of the database file to open */
  int mxPage,              /* Max number of in-memory cache pages */
  int nExtra               /* Extra bytes append to each in-memory page */

){
  Pager *pPager;
  int nameLen;
  OsFile fd;
  int rc;
  int tempFile;
  int readOnly = 0;
................................................................................
  pPager->zFilename = (char*)&pPager[1];
  pPager->zJournal = &pPager->zFilename[nameLen+1];
  strcpy(pPager->zFilename, zFilename);
  strcpy(pPager->zJournal, zFilename);
  strcpy(&pPager->zJournal[nameLen], "-journal");
  pPager->fd = fd;
  pPager->journalOpen = 0;

  pPager->ckptOpen = 0;
  pPager->ckptInUse = 0;
  pPager->nRef = 0;
  pPager->dbSize = -1;
  pPager->ckptSize = 0;
  pPager->ckptJSize = 0;
  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->noSync = pPager->tempFile;
  pPager->pFirst = 0;
  pPager->pLast = 0;
  pPager->nExtra = nExtra;
  memset(pPager->aHash, 0, sizeof(pPager->aHash));
  *ppPager = pPager;
  return SQLITE_OK;
}
................................................................................
      *ppPage = 0;
      return rc;
    }
    pPager->state = SQLITE_READLOCK;

    /* If a journal file exists, try to play it back.
    */
    if( sqliteOsFileExists(pPager->zJournal) ){
       int rc, dummy;

       /* Get a write lock on the database
       */
       rc = sqliteOsWriteLock(&pPager->fd);
       if( rc!=SQLITE_OK ){
         if( sqliteOsUnlock(&pPager->fd)!=SQLITE_OK ){
................................................................................
    assert( pPager->nRef>=0 );
    if( pPager->nRef==0 ){
      pager_reset(pPager);
    }
  }
  return SQLITE_OK;
}





















































/*
** Acquire a write-lock on the database.  The lock is removed when
** the any of the following happen:
**
**   *  sqlitepager_commit() is called.
**   *  sqlitepager_rollback() is called.
................................................................................
**   *  sqlitepager_close() is called.
**   *  sqlitepager_unref() is called to on every outstanding page.
**
** The parameter to this routine is a pointer to any open page of the
** database file.  Nothing changes about the page - it is used merely
** to acquire a pointer to the Pager structure and as proof that there
** is already a read-lock on the database.




**
** If the database is already write-locked, this routine is a no-op.
*/
int sqlitepager_begin(void *pData){
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;
................................................................................
  assert( pPager->state!=SQLITE_UNLOCK );
  if( pPager->state==SQLITE_READLOCK ){
    assert( pPager->aInJournal==0 );
    rc = sqliteOsWriteLock(&pPager->fd);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 );
    if( pPager->aInJournal==0 ){
      sqliteOsReadLock(&pPager->fd);
      return SQLITE_NOMEM;
    }
    rc = sqliteOsOpenExclusive(pPager->zJournal, &pPager->jfd,pPager->tempFile);
    if( rc!=SQLITE_OK ){
      sqliteFree(pPager->aInJournal);
      pPager->aInJournal = 0;
      sqliteOsReadLock(&pPager->fd);
      return SQLITE_CANTOPEN;
    }
    pPager->journalOpen = 1;
    pPager->needSync = 0;
    pPager->dirtyFile = 0;
    pPager->alwaysRollback = 0;
    pPager->state = SQLITE_WRITELOCK;
    sqlitepager_pagecount(pPager);
    pPager->origDbSize = pPager->dbSize;
    if( pager_old_format ){
      rc = sqliteOsWrite(&pPager->jfd, aOldJournalMagic,
                         sizeof(aOldJournalMagic));
    }else{
      rc = sqliteOsWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic));
    }
    if( rc==SQLITE_OK ){
      rc = write32bits(&pPager->jfd, pPager->dbSize);
    }
    if( rc!=SQLITE_OK ){
      rc = pager_unwritelock(pPager);
      if( rc==SQLITE_OK ){
        rc = SQLITE_FULL;
      }


    }
  }
  return rc;
}

/*
** Mark a data page as writeable.  The page is written into the journal 
................................................................................
  ** or both.
  **
  ** First check to see that the transaction journal exists and
  ** create it if it does not.
  */
  assert( pPager->state!=SQLITE_UNLOCK );
  rc = sqlitepager_begin(pData);
  pPager->dirtyFile = 1;
  if( rc!=SQLITE_OK ) return rc;


  assert( pPager->state==SQLITE_WRITELOCK );




  assert( pPager->journalOpen );


  /* The transaction journal now exists and we have a write lock on the
  ** main database file.  Write the current page to the transaction 
  ** journal if it is not there already.
  */

  if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
    rc = write32bits(&pPager->jfd, pPg->pgno);
    if( rc==SQLITE_OK ){
      rc = sqliteOsWrite(&pPager->jfd, pData, SQLITE_PAGE_SIZE);
    }
    if( rc!=SQLITE_OK ){
      sqlitepager_rollback(pPager);
      pPager->errMask |= PAGER_ERR_FULL;
................................................................................
  if( pPager->errMask!=0 ){
    rc = pager_errcode(pPager);
    return rc;
  }
  if( pPager->state!=SQLITE_WRITELOCK ){
    return SQLITE_ERROR;
  }
  assert( pPager->journalOpen );
  if( pPager->dirtyFile==0 ){
    /* Exit early (without doing the time-consuming sqliteOsSync() calls)
    ** if there have been no changes to the database file. */
    rc = pager_unwritelock(pPager);
    pPager->dbSize = -1;
    return rc;
  }

  if( pPager->needSync && sqliteOsSync(&pPager->jfd)!=SQLITE_OK ){
    goto commit_abort;
  }
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    if( pPg->dirty==0 ) continue;
    rc = sqliteOsSeek(&pPager->fd, (pPg->pgno-1)*(off_t)SQLITE_PAGE_SIZE);
    if( rc!=SQLITE_OK ) goto commit_abort;
................................................................................
** process is writing trash into the journal file (SQLITE_CORRUPT) or
** unless a prior malloc() failed (SQLITE_NOMEM).  Appropriate error
** codes are returned for all these occasions.  Otherwise,
** SQLITE_OK is returned.
*/
int sqlitepager_rollback(Pager *pPager){
  int rc;





  if( pPager->errMask!=0 && pPager->errMask!=PAGER_ERR_FULL ){
    if( pPager->state>=SQLITE_WRITELOCK ){
      pager_playback(pPager);
    }
    return pager_errcode(pPager);
  }
  if( pPager->state!=SQLITE_WRITELOCK ){
................................................................................
** This routine should be called with the transaction journal already
** open.  A new checkpoint journal is created that can be used to rollback
** changes of a single SQL command within a larger transaction.
*/
int sqlitepager_ckpt_begin(Pager *pPager){
  int rc;
  char zTemp[SQLITE_TEMPNAME_SIZE];




  assert( pPager->journalOpen );
  assert( !pPager->ckptInUse );
  pPager->aInCkpt = sqliteMalloc( pPager->dbSize/8 + 1 );
  if( pPager->aInCkpt==0 ){
    sqliteOsReadLock(&pPager->fd);
    return SQLITE_NOMEM;
  }
................................................................................
      pNext = pPg->pNextCkpt;
      assert( pPg->inCkpt );
      pPg->inCkpt = 0;
      pPg->pPrevCkpt = pPg->pNextCkpt = 0;
    }
    pPager->pCkpt = 0;
  }

  return SQLITE_OK;
}

/*
** Rollback a checkpoint.
*/
int sqlitepager_ckpt_rollback(Pager *pPager){
................................................................................
  int rc;
  if( pPager->ckptInUse ){
    rc = pager_ckpt_playback(pPager);
    sqlitepager_ckpt_commit(pPager);
  }else{
    rc = SQLITE_OK;
  }

  return rc;
}

#ifdef SQLITE_TEST
/*
** Print a listing of all referenced pages and their ref count.
*/

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.60 2002/12/02 04:25:21 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
  int nExtra;                 /* Add this many bytes to each in-memory page */
  void (*xDestructor)(void*); /* Call this routine when freeing pages */
  int nPage;                  /* Total number of in-memory pages */
  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 */
  u8 journalOpen;             /* True if journal file descriptors is valid */
  u8 useJournal;              /* Do not use a rollback journal on this file */
  u8 ckptOpen;                /* True if the checkpoint journal is open */
  u8 ckptInUse;               /* True we are in a checkpoint */
  u8 ckptAutoopen;            /* Open ckpt journal when main journal is opened*/
  u8 noSync;                  /* Do not sync the journal if true */
  u8 state;                   /* SQLITE_UNLOCK, _READLOCK or _WRITELOCK */
  u8 errMask;                 /* One of several kinds of errors */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 needSync;                /* True if an fsync() is needed on the journal */
  u8 dirtyFile;               /* True if database file has changed in any way */
................................................................................
  PgHdr *pPg;
  if( pPager->state<SQLITE_WRITELOCK ) return SQLITE_OK;
  sqlitepager_ckpt_commit(pPager);
  if( pPager->ckptOpen ){
    sqliteOsClose(&pPager->cpfd);
    pPager->ckptOpen = 0;
  }
  if( pPager->journalOpen ){
    sqliteOsClose(&pPager->jfd);
    pPager->journalOpen = 0;
    sqliteOsDelete(pPager->zJournal);

    sqliteFree( pPager->aInJournal );
    pPager->aInJournal = 0;
    for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
      pPg->inJournal = 0;
      pPg->dirty = 0;
    }
  }else{
    assert( pPager->dirtyFile==0 || pPager->useJournal==0 );
  }
  rc = sqliteOsReadLock(&pPager->fd);
  if( rc==SQLITE_OK ){
    pPager->state = SQLITE_READLOCK;
  }else{
    /* This can only happen if a process does a BEGIN, then forks and the
    ** child process does the COMMIT.  Because of the semantics of unix
    ** file locking, the unlock will fail.
    */
................................................................................
** and used as the file to be cached.  The file will be deleted
** automatically when it is closed.
*/
int sqlitepager_open(
  Pager **ppPager,         /* Return the Pager structure here */
  const char *zFilename,   /* Name of the database file to open */
  int mxPage,              /* Max number of in-memory cache pages */
  int nExtra,              /* Extra bytes append to each in-memory page */
  int useJournal           /* TRUE to use a rollback journal on this file */
){
  Pager *pPager;
  int nameLen;
  OsFile fd;
  int rc;
  int tempFile;
  int readOnly = 0;
................................................................................
  pPager->zFilename = (char*)&pPager[1];
  pPager->zJournal = &pPager->zFilename[nameLen+1];
  strcpy(pPager->zFilename, zFilename);
  strcpy(pPager->zJournal, zFilename);
  strcpy(&pPager->zJournal[nameLen], "-journal");
  pPager->fd = fd;
  pPager->journalOpen = 0;
  pPager->useJournal = useJournal;
  pPager->ckptOpen = 0;
  pPager->ckptInUse = 0;
  pPager->nRef = 0;
  pPager->dbSize = -1;
  pPager->ckptSize = 0;
  pPager->ckptJSize = 0;
  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->noSync = pPager->tempFile || !useJournal;
  pPager->pFirst = 0;
  pPager->pLast = 0;
  pPager->nExtra = nExtra;
  memset(pPager->aHash, 0, sizeof(pPager->aHash));
  *ppPager = pPager;
  return SQLITE_OK;
}
................................................................................
      *ppPage = 0;
      return rc;
    }
    pPager->state = SQLITE_READLOCK;

    /* If a journal file exists, try to play it back.
    */
    if( pPager->useJournal && sqliteOsFileExists(pPager->zJournal) ){
       int rc, dummy;

       /* Get a write lock on the database
       */
       rc = sqliteOsWriteLock(&pPager->fd);
       if( rc!=SQLITE_OK ){
         if( sqliteOsUnlock(&pPager->fd)!=SQLITE_OK ){
................................................................................
    assert( pPager->nRef>=0 );
    if( pPager->nRef==0 ){
      pager_reset(pPager);
    }
  }
  return SQLITE_OK;
}

/*
** Create a journal file for pPager.  There should already be a write
** lock on the database file when this routine is called.
**
** Return SQLITE_OK if everything.  Return an error code and release the
** write lock if anything goes wrong.
*/
static int pager_open_journal(Pager *pPager){
  int rc;
  assert( pPager->state==SQLITE_WRITELOCK );
  assert( pPager->journalOpen==0 );
  assert( pPager->useJournal );
  pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 );
  if( pPager->aInJournal==0 ){
    sqliteOsReadLock(&pPager->fd);
    pPager->state = SQLITE_READLOCK;
    return SQLITE_NOMEM;
  }
  rc = sqliteOsOpenExclusive(pPager->zJournal, &pPager->jfd,pPager->tempFile);
  if( rc!=SQLITE_OK ){
    sqliteFree(pPager->aInJournal);
    pPager->aInJournal = 0;
    sqliteOsReadLock(&pPager->fd);
    pPager->state = SQLITE_READLOCK;
    return SQLITE_CANTOPEN;
  }
  pPager->journalOpen = 1;
  pPager->needSync = 0;
  pPager->alwaysRollback = 0;
  sqlitepager_pagecount(pPager);
  pPager->origDbSize = pPager->dbSize;
  if( pager_old_format ){
    rc = sqliteOsWrite(&pPager->jfd, aOldJournalMagic,
                       sizeof(aOldJournalMagic));
  }else{
    rc = sqliteOsWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic));
  }
  if( rc==SQLITE_OK ){
    rc = write32bits(&pPager->jfd, pPager->dbSize);
  }
  if( pPager->ckptAutoopen && rc==SQLITE_OK ){
    rc = sqlitepager_ckpt_begin(pPager);
  }
  if( rc!=SQLITE_OK ){
    rc = pager_unwritelock(pPager);
    if( rc==SQLITE_OK ){
      rc = SQLITE_FULL;
    }
  }
  return rc;  
}

/*
** Acquire a write-lock on the database.  The lock is removed when
** the any of the following happen:
**
**   *  sqlitepager_commit() is called.
**   *  sqlitepager_rollback() is called.
................................................................................
**   *  sqlitepager_close() is called.
**   *  sqlitepager_unref() is called to on every outstanding page.
**
** The parameter to this routine is a pointer to any open page of the
** database file.  Nothing changes about the page - it is used merely
** to acquire a pointer to the Pager structure and as proof that there
** is already a read-lock on the database.
**
** A journal file is opened if this is not a temporary file.  For
** temporary files, the opening of the journal file is deferred until
** there is an actual need to write to the journal.
**
** If the database is already write-locked, this routine is a no-op.
*/
int sqlitepager_begin(void *pData){
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;
................................................................................
  assert( pPager->state!=SQLITE_UNLOCK );
  if( pPager->state==SQLITE_READLOCK ){
    assert( pPager->aInJournal==0 );
    rc = sqliteOsWriteLock(&pPager->fd);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    pPager->state = SQLITE_WRITELOCK;













    pPager->dirtyFile = 0;


















    if( pPager->useJournal && !pPager->tempFile ){
      rc = pager_open_journal(pPager);
    }
  }
  return rc;
}

/*
** Mark a data page as writeable.  The page is written into the journal 
................................................................................
  ** or both.
  **
  ** First check to see that the transaction journal exists and
  ** create it if it does not.
  */
  assert( pPager->state!=SQLITE_UNLOCK );
  rc = sqlitepager_begin(pData);

  if( rc!=SQLITE_OK ){
    return rc;
  }
  assert( pPager->state==SQLITE_WRITELOCK );
  if( !pPager->journalOpen && pPager->useJournal ){
    rc = pager_open_journal(pPager);
    if( rc!=SQLITE_OK ) return rc;
  }
  assert( pPager->journalOpen || !pPager->useJournal );
  pPager->dirtyFile = 1;

  /* The transaction journal now exists and we have a write lock on the
  ** main database file.  Write the current page to the transaction 
  ** journal if it is not there already.
  */
  if( !pPg->inJournal && pPager->useJournal 
         && (int)pPg->pgno <= pPager->origDbSize ){
    rc = write32bits(&pPager->jfd, pPg->pgno);
    if( rc==SQLITE_OK ){
      rc = sqliteOsWrite(&pPager->jfd, pData, SQLITE_PAGE_SIZE);
    }
    if( rc!=SQLITE_OK ){
      sqlitepager_rollback(pPager);
      pPager->errMask |= PAGER_ERR_FULL;
................................................................................
  if( pPager->errMask!=0 ){
    rc = pager_errcode(pPager);
    return rc;
  }
  if( pPager->state!=SQLITE_WRITELOCK ){
    return SQLITE_ERROR;
  }

  if( pPager->dirtyFile==0 ){
    /* Exit early (without doing the time-consuming sqliteOsSync() calls)
    ** if there have been no changes to the database file. */
    rc = pager_unwritelock(pPager);
    pPager->dbSize = -1;
    return rc;
  }
  assert( pPager->journalOpen );
  if( pPager->needSync && sqliteOsSync(&pPager->jfd)!=SQLITE_OK ){
    goto commit_abort;
  }
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    if( pPg->dirty==0 ) continue;
    rc = sqliteOsSeek(&pPager->fd, (pPg->pgno-1)*(off_t)SQLITE_PAGE_SIZE);
    if( rc!=SQLITE_OK ) goto commit_abort;
................................................................................
** process is writing trash into the journal file (SQLITE_CORRUPT) or
** unless a prior malloc() failed (SQLITE_NOMEM).  Appropriate error
** codes are returned for all these occasions.  Otherwise,
** SQLITE_OK is returned.
*/
int sqlitepager_rollback(Pager *pPager){
  int rc;
  if( !pPager->dirtyFile || !pPager->journalOpen ){
    rc = pager_unwritelock(pPager);
    pPager->dbSize = -1;
    return rc;
  }
  if( pPager->errMask!=0 && pPager->errMask!=PAGER_ERR_FULL ){
    if( pPager->state>=SQLITE_WRITELOCK ){
      pager_playback(pPager);
    }
    return pager_errcode(pPager);
  }
  if( pPager->state!=SQLITE_WRITELOCK ){
................................................................................
** This routine should be called with the transaction journal already
** open.  A new checkpoint journal is created that can be used to rollback
** changes of a single SQL command within a larger transaction.
*/
int sqlitepager_ckpt_begin(Pager *pPager){
  int rc;
  char zTemp[SQLITE_TEMPNAME_SIZE];
  if( !pPager->journalOpen ){
    pPager->ckptAutoopen = 1;
    return SQLITE_OK;
  }
  assert( pPager->journalOpen );
  assert( !pPager->ckptInUse );
  pPager->aInCkpt = sqliteMalloc( pPager->dbSize/8 + 1 );
  if( pPager->aInCkpt==0 ){
    sqliteOsReadLock(&pPager->fd);
    return SQLITE_NOMEM;
  }
................................................................................
      pNext = pPg->pNextCkpt;
      assert( pPg->inCkpt );
      pPg->inCkpt = 0;
      pPg->pPrevCkpt = pPg->pNextCkpt = 0;
    }
    pPager->pCkpt = 0;
  }
  pPager->ckptAutoopen = 0;
  return SQLITE_OK;
}

/*
** Rollback a checkpoint.
*/
int sqlitepager_ckpt_rollback(Pager *pPager){
................................................................................
  int rc;
  if( pPager->ckptInUse ){
    rc = pager_ckpt_playback(pPager);
    sqlitepager_ckpt_commit(pPager);
  }else{
    rc = SQLITE_OK;
  }
  pPager->ckptAutoopen = 0;
  return rc;
}

#ifdef SQLITE_TEST
/*
** Print a listing of all referenced pages and their ref count.
*/

**    May you share freely, never taking more than you give.
**
*************************************************************************
** 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 1.17 2002/08/12 12:29:57 drh Exp $
*/

/*
** The size of one page
**
** You can change this value to another (reasonable) power of two
** such as 512, 2048, 4096, or 8192 and things will still work.  But
................................................................................
*/
typedef struct Pager Pager;

/*
** See source code comments for a detailed description of the following
** routines:
*/
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*);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** 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 1.18 2002/12/02 04:25:21 drh Exp $
*/

/*
** The size of one page
**
** You can change this value to another (reasonable) power of two
** such as 512, 2048, 4096, or 8192 and things will still work.  But
................................................................................
*/
typedef struct Pager Pager;

/*
** See source code comments for a detailed description of the following
** routines:
*/
int sqlitepager_open(Pager **ppPager, const char *zFilename,
                     int nPage, int nExtra, int useJournal);
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*);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the pager.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test2.c,v 1.12 2002/12/01 02:00:58 drh Exp $
*/
#include "os.h"
#include "sqliteInt.h"
#include "pager.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
  char zBuf[100];
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME N-PAGE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[2], &nPage) ) return TCL_ERROR;
  rc = sqlitepager_open(&pPager, argv[1], nPage, 0);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sprintf(zBuf,"0x%x",(int)pPager);
  Tcl_AppendResult(interp, zBuf, 0);
  return TCL_OK;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the pager.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test2.c,v 1.13 2002/12/02 04:25:21 drh Exp $
*/
#include "os.h"
#include "sqliteInt.h"
#include "pager.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
  char zBuf[100];
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME N-PAGE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[2], &nPage) ) return TCL_ERROR;
  rc = sqlitepager_open(&pPager, argv[1], nPage, 0, 1);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sprintf(zBuf,"0x%x",(int)pPager);
  Tcl_AppendResult(interp, zBuf, 0);
  return TCL_OK;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the btree.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test3.c,v 1.20 2002/11/24 14:52:27 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
  int rc;
  char zBuf[100];
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME\"", 0);
    return TCL_ERROR;
  }
  rc = sqliteBtreeOpen(argv[1], 0666, 1000, &pBt);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sprintf(zBuf,"%p", pBt);
  if( strncmp(zBuf,"0x",2) ){
    sprintf(zBuf, "0x%p", pBt);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the btree.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test3.c,v 1.21 2002/12/02 04:25:21 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
  int rc;
  char zBuf[100];
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME\"", 0);
    return TCL_ERROR;
  }
  rc = sqliteBtreeOpen(argv[1], 0, 1000, &pBt);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sprintf(zBuf,"%p", pBt);
  if( strncmp(zBuf,"0x",2) ){
    sprintf(zBuf, "0x%p", pBt);

**
** 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 1.184 2002/11/11 00:05:43 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The makefile scans this source file and creates the following
** array of string constants which are the names of all VDBE opcodes.
................................................................................
  Cursor *pCx;
  VERIFY( if( i<0 ) goto bad_instruction; )
  if( expandCursorArraySize(p, i) ) goto no_mem;
  pCx = &p->aCsr[i];
  cleanupCursor(pCx);
  memset(pCx, 0, sizeof(*pCx));
  pCx->nullRow = 1;
  rc = sqliteBtreeOpen(0, 0, TEMP_PAGES, &pCx->pBt);
  if( rc==SQLITE_OK ){
    rc = sqliteBtreeBeginTrans(pCx->pBt);
  }
  if( rc==SQLITE_OK ){
    if( pOp->p2 ){
      int pgno;
      rc = sqliteBtreeCreateIndex(pCx->pBt, &pgno);

**
** 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 1.185 2002/12/02 04:25:21 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The makefile scans this source file and creates the following
** array of string constants which are the names of all VDBE opcodes.
................................................................................
  Cursor *pCx;
  VERIFY( if( i<0 ) goto bad_instruction; )
  if( expandCursorArraySize(p, i) ) goto no_mem;
  pCx = &p->aCsr[i];
  cleanupCursor(pCx);
  memset(pCx, 0, sizeof(*pCx));
  pCx->nullRow = 1;
  rc = sqliteBtreeOpen(0, 1, TEMP_PAGES, &pCx->pBt);
  if( rc==SQLITE_OK ){
    rc = sqliteBtreeBeginTrans(pCx->pBt);
  }
  if( rc==SQLITE_OK ){
    if( pOp->p2 ){
      int pgno;
      rc = sqliteBtreeCreateIndex(pCx->pBt, &pgno);