SQLite

**
*************************************************************************
** 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 1.397 2007/08/24 03:51:34 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The version of the library
*/

  /* The temp-database schema is allocated differently from the other schema
  ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
  ** So it needs to be freed here. Todo: Why not roll the temp schema into
  ** the same sqliteMalloc() as the one that allocates the database 
  ** structure?
  */
  sqlite3_free(db->aDb[1].pSchema);
  sqlite3_vfs_release(db->pVfs);
  sqlite3_mutex_leave(db->mutex);
  sqlite3_mutex_free(db->mutex);
  sqlite3_free(db);
  return SQLITE_OK;
}

/*

  int rc;
  pVfs = sqlite3_vfs_find(0);

  /* This function works in milliseconds, but the underlying OsSleep() 
  ** API uses microseconds. Hence the 1000's.
  */
  rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
  sqlite3_vfs_release(pVfs);
  return rc;
}

/*
** Enable or disable the extended result codes.
*/
int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
  sqlite3_mutex_enter(db->mutex);
  db->errMask = onoff ? 0xffffffff : 0xff;
  sqlite3_mutex_leave(db->mutex);
  return SQLITE_OK;
}

    vfsList = sqlite3OsDefaultVfs();
    isInit = 1;
  }
  for(pVfs = vfsList; pVfs; pVfs=pVfs->pNext){
    if( zVfs==0 ) break;
    if( strcmp(zVfs, pVfs->zName)==0 ) break;
  }
  if( pVfs ){
    pVfs->nRef++;
    assert( pVfs->nRef==1 || pVfs->vfsMutex!=0 );
    assert( pVfs->nRef>1 || pVfs->vfsMutex==0 );
    if( pVfs->vfsMutex==0 ){
      pVfs->vfsMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    }
  }
  sqlite3_mutex_leave(mutex);
  return pVfs;
}

/*
** Release a VFS once it is no longer needed.
*/
int sqlite3_vfs_release(sqlite3_vfs *pVfs){
  sqlite3_mutex *mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
  sqlite3_mutex_enter(mutex);
  assert( pVfs->nRef>0 );
  pVfs->nRef--;
  if( pVfs->nRef==0 && pVfs->vfsMutex ){
    sqlite3_mutex_free(pVfs->vfsMutex);
    pVfs->vfsMutex = 0;
  }
  sqlite3_mutex_leave(mutex);
  return SQLITE_OK;
}

/*
** Unlink a VFS from the linked list
*/
static void vfsUnlink(sqlite3_vfs *pVfs){
  assert( sqlite3_mutex_held(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER)) );
  if( vfsList==pVfs ){
    vfsList = pVfs->pNext;

** initialized structures.
*/
sqlite3_vfs *sqlite3OsDefaultVfs(void){
  static sqlite3_vfs unixVfs = {
    1,                  /* iVersion */
    sizeof(unixFile),   /* szOsFile */
    MAX_PATHNAME,       /* mxPathname */
    0,                  /* nRef */
    0,                  /* vfsMutex */
    0,                  /* pNext */
    "unix",             /* zName */
    0,                  /* pAppData */
  
    unixOpen,           /* xOpen */
    unixDelete,         /* xDelete */
    unixAccess,         /* xAccess */

** initialized structures.
*/
sqlite3_vfs *sqlite3OsDefaultVfs(void){
  static sqlite3_vfs winVfs = {
    1,                 /* iVersion */
    sizeof(winFile),   /* szOsFile */
    MAX_PATH,          /* mxPathname */
    0,                 /* nRef */
    0,                 /* vfsMutex */
    0,                 /* pNext */
    "win32",           /* zName */
    0,                 /* pAppData */
  
    winOpen,           /* xOpen */
    winDelete,         /* xDelete */
    winAccess,         /* xAccess */

** 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 1.374 2007/08/24 11:52:29 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*

/*
** 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 sqlite3PagerGet() and is only held open until the
** last page is released using sqlite3PagerUnref().
**
** If zFilename is NULL then a randomly-named temporary file is created
** and
** automatically when it is closed.
**
** If zFilename is ":memory:" then all information is held in cache.
** It is never written to disk.  This can be used to implement an
** in-memory database.
*/
int sqlite3PagerOpen(

  int i;
  int tempFile = 0;
  int memDb = 0;
  int readOnly = 0;
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
  int journalFileSize = sqlite3JournalSize(pVfs);
  int nDefaultPage = SQLITE_DEFAULT_PAGE_SIZE;     /* Default page size. */



  /* The default return is a NULL pointer */
  *ppPager = 0;

























  /* Allocate memory for the pager structure */
  pPager = sqlite3MallocZero(
    sizeof(*pPager) +           /* Pager structure */
    journalFileSize +           /* The journal file structure */ 
    pVfs->szOsFile * 2 +        /* The db and stmt journal files */ 
    pVfs->mxPathname * 3 + 30   /* zFilename, zDirectory, zJournal */
  );
  if( !pPager ){

    return SQLITE_NOMEM;
  }
  pPtr = (u8 *)&pPager[1];
  pPager->fd = (sqlite3_file*)&pPtr[pVfs->szOsFile*0];
  pPager->stfd = (sqlite3_file*)&pPtr[pVfs->szOsFile*1];
  pPager->jfd = (sqlite3_file*)&pPtr[pVfs->szOsFile*2];
  pPager->zFilename = (char*)&pPtr[pVfs->szOsFile*2+journalFileSize];
  pPager->zDirectory = &pPager->zFilename[pVfs->mxPathname];
  pPager->zJournal = &pPager->zDirectory[pVfs->mxPathname];
  pPager->pVfs = pVfs;



  /* Open the pager file.
  */
  if( zFilename && zFilename[0] ){
#ifndef SQLITE_OMIT_MEMORYDB
    if( strcmp(zFilename,":memory:")==0 ){
      memDb = 1;
      pPager->zFilename[0] = '\0';
    }else
#endif
    {
      rc = sqlite3OsFullPathname(pVfs, zFilename, pPager->zFilename);
      if( rc==SQLITE_OK ){
        if( strlen(pPager->zFilename)>(pVfs->mxPathname - strlen("-journal")) ){
          rc = SQLITE_CANTOPEN;
        }else{



          int oflag = 
              (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MAIN_DB);
          int fout = 0;
          rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd, oflag, &fout);
          readOnly = (fout&SQLITE_OPEN_READONLY);
 
          /* If the file was successfully opened for read/write access,
          ** choose a default page size in case we have to create the
          ** database file. The default page size is the maximum of:
          **
          **    + SQLITE_DEFAULT_PAGE_SIZE,
          **    + The value returned by sqlite3OsSectorSize()
          **    + The largest page size that can be written atomically.
          */
          if( rc==SQLITE_OK && !readOnly ){
            int iSectorSize = sqlite3OsSectorSize(pPager->fd);
            if( nDefaultPage<iSectorSize ){
              nDefaultPage = iSectorSize;
            }
#ifdef SQLITE_ENABLE_ATOMIC_WRITE
            {
              int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
              int ii;
              assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
              assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
              assert(SQLITE_MAX_DEFAULT_PAGE_SIZE<=65536);
              for(ii=nDefaultPage; ii<=SQLITE_MAX_DEFAULT_PAGE_SIZE; ii=ii*2){
                if( iDc&(SQLITE_IOCAP_ATOMIC|(ii>>8)) ) nDefaultPage = ii;
              }
            }
#endif
            if( nDefaultPage>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
              nDefaultPage = SQLITE_MAX_DEFAULT_PAGE_SIZE;
            }
          }
        }
      }
    }
  }else{
    /* If a temporary file is requested, it is not opened immediately.
    ** In this case we accept the default page size and delay actually
    ** opening the file until the first call to OsWrite().
    */ 
    tempFile = 1;
    pPager->state = PAGER_EXCLUSIVE;
  }

    return ((rc==SQLITE_OK)?SQLITE_NOMEM:rc);
  }

  PAGERTRACE3("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename);
  IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))

  /* Fill in Pager.zDirectory[] */
  memcpy(pPager->zDirectory, pPager->zFilename, pVfs->mxPathname);
  for(i=strlen(pPager->zDirectory); i>0 && pPager->zDirectory[i-1]!='/'; i--){}
  if( i>0 ) pPager->zDirectory[i-1] = 0;

  /* Fill in Pager.zJournal[] */
  memcpy(pPager->zJournal, pPager->zFilename, pVfs->mxPathname);
  memcpy(&pPager->zJournal[strlen(pPager->zJournal)], "-journal", 9);

  /* pPager->journalOpen = 0; */
  pPager->useJournal = useJournal && !memDb;
  pPager->noReadlock = noReadlock && readOnly;
  /* pPager->stmtOpen = 0; */
  /* pPager->stmtInUse = 0; */
  /* pPager->nRef = 0; */
  pPager->dbSize = memDb-1;
  pPager->pageSize = nDefaultPage;
  /* pPager->stmtSize = 0; */
  /* pPager->stmtJSize = 0; */
  /* pPager->nPage = 0; */
  pPager->mxPage = 100;
  pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
  assert( PAGER_UNLOCK==0 );
  /* pPager->state = PAGER_UNLOCK; */

  /* pPager->errMask = 0; */
  pPager->tempFile = tempFile;
  assert( tempFile==PAGER_LOCKINGMODE_NORMAL 
          || tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
  assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
  pPager->exclusiveMode = tempFile; 
  pPager->memDb = memDb;

      while( pPg && !pPg->dirty ){ pPg = pPg->pDirty; }
      pPager->pDirty = pPg;
      goto sync_exit;
    }
    pPager->pDirty = 0;

    /* Sync the database file. */
    if( !pPager->noSync ){ 
      rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
    }
    IOTRACE(("DBSYNC %p\n", pPager))

    pPager->state = PAGER_SYNCED;
  }else if( MEMDB && nTrunc!=0 ){
    rc = sqlite3PagerTruncate(pPager, nTrunc);

** on how SQLite interfaces are suppose to operate.
**
** The name of this file under configuration management is "sqlite.h.in".
** The makefile makes some minor changes to this file (such as inserting
** the version number) and changes its name to "sqlite3.h" as
** part of the build process.
**
** @(#) $Id: sqlite.h.in,v 1.239 2007/08/24 03:51:34 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.

** versions of SQLite.  Additional fields may be appended to this
** object when the iVersion value is increased.
**
** The szOsFile field is the size of the subclassed sqlite3_file
** structure used by this VFS.  mxPathname is the maximum length of
** a pathname in this VFS.
**
** The nRef field is incremented and decremented by SQLite to keep
** count of the number of users of the VFS.  This field and
** vfsMutex, pNext, and pPrev are the only fields in the sqlite3_vfs 
** structure that SQLite will ever modify.  SQLite will only access
** or modify these fields while holding a particular static mutex.
** The application should never modify any fields of the sqlite3_vfs
** object once the object has been registered.
** 
** The sqlite3_vfs.vfsMutex is a mutex used by the OS interface.
** It should initially be NULL.  SQLite will initialize this field
** using sqlite3_mutex_alloc() upon first use of the adaptor
** by sqlite3_open_v2() and will deallocate the mutex when the
** last user closes.  In other words, vfsMutex will be allocated
** when nRef transitions from 0 to 1 and will be deallocated when
** nRef transitions from 1 to 0.
**
** Registered vfs modules are kept on a linked list formed by
** the pNext pointer.  The [sqlite3_register_vfs()]
** and [sqlite3_unregister_vfs()] interfaces manage this list
** in a thread-safe way.  The [sqlite3_find_vfs()] interface
** searches the list.






**
** The zName field holds the name of the VFS module.  The name must
** be unique across all VFS modules.
**
** SQLite will guarantee that the zFilename string passed to
** xOpen() is a full pathname as generated by xFullPathname() and
** that the string will be valid and unchanged until xClose() is

** time.
*/
typedef struct sqlite3_vfs sqlite3_vfs;
struct sqlite3_vfs {
  int iVersion;            /* Structure version number */
  int szOsFile;            /* Size of subclassed sqlite3_file */
  int mxPathname;          /* Maximum file pathname length */
  int nRef;                /* Number of references to this structure */
  sqlite3_mutex *vfsMutex; /* A mutex for this VFS */
  sqlite3_vfs *pNext;      /* Next registered VFS */
  const char *zName;       /* Name of this virtual file system */
  void *pAppData;          /* Application context */
  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
               int flags, int *pOutFlags);
  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags);
  int (*xGetTempName)(sqlite3_vfs*, char *zOut);
  int (*xFullPathname)(sqlite3_vfs*, const char *zName, char *zOut);
  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);

** single default VFS that is appropriate for the host computer.
** New VFSes can be registered and existing VFSes can be unregistered.
** The following interfaces are provided.
**
** The sqlite3_vfs_find() interface returns a pointer to a VFS given its
** name.  Names are case sensitive.  If there is no match, a NULL
** pointer is returned.  If zVfsName is NULL then the default 
** VFS is returned.  If a valid VFS pointer is returned, its
** vfsMutex field will have been initialized and nRef will be
** greater than zero.  The sqlite3_vfs_release() function should
** be used to release the VFS when it is no longer needed.
**
** New VFSes are registered with sqlite3_vfs_register().  Each
** new VFS becomes the default VFS if the makeDflt flag is set.
** The same VFS can be registered multiple times without injury.
** To make an existing VFS into the default VFS, register it again
** with the makeDflt flag set.
** 
** Unregister a VFS with the sqlite3_vfs_unregister() interface.
** If the default VFS is unregistered, another VFS is chosen as
** the default.  The choice for the new VFS is arbitrary.
*/
sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
int sqlite3_vfs_release(sqlite3_vfs*);
int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
int sqlite3_vfs_unregister(sqlite3_vfs*);

/*
** CAPI3REF: Mutexes
**
** The SQLite core uses these routines for thread

**    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 1.81 2007/08/22 02:56:44 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

/*

    return TCL_ERROR;
  }
  nRefSqlite3--;
  if( nRefSqlite3==0 ){
    sqlite3_mutex_leave(sDb.mutex);
    sqlite3_mutex_free(sDb.mutex);
    sDb.mutex = 0;
    sqlite3_vfs_release(sDb.pVfs);
    sDb.pVfs = 0;
  }
  return TCL_OK;
}


/*

  const char *zCrashFile;
  int nCrashFile, iDc, iSectorSize;

  static sqlite3_vfs crashVfs = {
    1,                  /* iVersion */
    0,                  /* szOsFile */
    0,                  /* mxPathname */
    0,                  /* nRef */
    0,                  /* vfsMutex */
    0,                  /* pNext */
    "crash",            /* zName */
    0,                  /* pAppData */
  
    cfOpen,               /* xOpen */
    cfDelete,             /* xDelete */
    cfAccess,             /* xAccess */

    sqlite3_vfs *pOriginalVfs = sqlite3_vfs_find(0);
    crashVfs.xDlError = pOriginalVfs->xDlError;
    crashVfs.xDlSym = pOriginalVfs->xDlSym;
    crashVfs.xDlClose = pOriginalVfs->xDlClose;
    crashVfs.mxPathname = pOriginalVfs->mxPathname;
    crashVfs.pAppData = (void *)pOriginalVfs;
    crashVfs.szOsFile = sizeof(CrashFile) + pOriginalVfs->szOsFile;
    sqlite3_vfs_release(pOriginalVfs);
    /* sqlite3_vfs_unregister(pOriginalVfs); */
    sqlite3_vfs_register(&crashVfs, 1);
  }

  iDc = -1;
  iSectorSize = -1;

# 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.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is page cache subsystem.
#
# $Id: pager.test,v 1.28 2007/04/05 17:15:53 danielk1977 Exp $


set testdir [file dirname $argv0]
source $testdir/tester.tcl

if {[info commands pager_open]!=""} {
db close

do_test pager-4.6.1 {
  pager_close [pager_open ptf2.db -15]
} {}

# Test truncate on an in-memory database is Ok.
ifcapable memorydb {
  do_test pager-4.6.2 {

    set ::p2 [pager_open :memory: 10]
    pager_truncate $::p2 5
  } {}
  do_test pager-4.6.3 {
    for {set i 1} {$i<5} {incr i} {
      set p [page_get $::p2 $i]
      page_write $p "Page $i"

} {{CREATE TABLE abc(a, b, c)}}

do_test pager-6.5 {
  db2 close
} {}
}
finish_test