SQLite

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.427 2007/09/17 07:02:57 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

  */
  if( (flags & BTREE_PRIVATE)==0
   && isMemdb==0
   && (pSqlite->flags & SQLITE_Vtab)==0
   && zFilename && zFilename[0]
  ){
    if( sqlite3SharedCacheEnabled ){
      int nFullPathname = pVfs->mxPathname+1;
      char *zFullPathname = (char *)sqlite3_malloc(nFullPathname);
      sqlite3_mutex *mutexShared;
      p->sharable = 1;
      if( pSqlite ){
        pSqlite->flags |= SQLITE_SharedCache;
      }
      if( !zFullPathname ){
        sqlite3_free(p);
        return SQLITE_NOMEM;
      }
      sqlite3OsFullPathname(pVfs, zFilename, nFullPathname, zFullPathname);
      mutexShared = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
      sqlite3_mutex_enter(mutexShared);
      for(pBt=sqlite3SharedCacheList; pBt; pBt=pBt->pNext){
        assert( pBt->nRef>0 );
        if( 0==strcmp(zFullPathname, sqlite3PagerFilename(pBt->pPager))
                 && sqlite3PagerVfs(pBt->pPager)==pVfs ){
          p->pBt = pBt;

}
int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  return pVfs->xDelete(pVfs, zPath, dirSync);
}
int sqlite3OsAccess(sqlite3_vfs *pVfs, const char *zPath, int flags){
  return pVfs->xAccess(pVfs, zPath, flags);
}
int sqlite3OsGetTempname(sqlite3_vfs *pVfs, int nBufOut, char *zBufOut){
  return pVfs->xGetTempname(pVfs, nBufOut, zBufOut);
}
int sqlite3OsFullPathname(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int nPathOut, 
  char *zPathOut
){
  return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
}
void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
  return pVfs->xDlOpen(pVfs, zPath);
}
void sqlite3OsDlError(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
  pVfs->xDlError(pVfs, nByte, zBufOut);
}

/* 
** Functions for accessing sqlite3_vfs methods 
*/
int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *);
int sqlite3OsDelete(sqlite3_vfs *, const char *, int);
int sqlite3OsAccess(sqlite3_vfs *, const char *, int);
int sqlite3OsGetTempname(sqlite3_vfs *, int, char *);
int sqlite3OsFullPathname(sqlite3_vfs *, const char *, int, char *);
void *sqlite3OsDlOpen(sqlite3_vfs *, const char *);
void sqlite3OsDlError(sqlite3_vfs *, int, char *);
void *sqlite3OsDlSym(sqlite3_vfs *, void *, const char *);
void sqlite3OsDlClose(sqlite3_vfs *, void *);
int sqlite3OsRandomness(sqlite3_vfs *, int, char *);
int sqlite3OsSleep(sqlite3_vfs *, int);
int sqlite3OsCurrentTime(sqlite3_vfs *, double*);

}

/*
** Create a temporary file name in zBuf.  zBuf must be allocated
** by the calling process and must be big enough to hold at least
** pVfs->mxPathname bytes.
*/
static int unixGetTempname(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  static const char *azDirs[] = {
     0,
     "/var/tmp",
     "/usr/tmp",
     "/tmp",
     ".",
  };

    if( !S_ISDIR(buf.st_mode) ) continue;
    if( access(azDirs[i], 07) ) continue;
    zDir = azDirs[i];
    break;
  }
  do{
    assert( pVfs->mxPathname==MAX_PATHNAME );
    assert( nBuf>=MAX_PATHNAME );
    sqlite3_snprintf(MAX_PATHNAME-17, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
    j = strlen(zBuf);
    sqlite3Randomness(15, &zBuf[j]);
    for(i=0; i<15; i++, j++){
      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
    }
    zBuf[j] = 0;

** is stored as a nul-terminated string in the buffer pointed to by
** zPath. 
**
** zOut points to a buffer of at least sqlite3_vfs.mxPathname bytes 
** (in this case, MAX_PATHNAME bytes). The full-path is written to
** this buffer before returning.
*/
static int unixFullPathname(
  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
  const char *zPath,            /* Possibly relative input path */
  int nOut,                     /* Size of output buffer in bytes */
  char *zOut                    /* Output buffer */
){

  /* It's odd to simulate an io-error here, but really this is just
  ** using the io-error infrastructure to test that SQLite handles this
  ** function failing. This function could fail if, for example, the
  ** current working directly has been unlinked.
  */
  SimulateIOError( return SQLITE_ERROR );

}


/*
** Create a temporary file name in zBuf.  zBuf must be big enough to
** hold at pVfs->mxPathname characters.
*/
static int winGetTempname(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  static char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  int i, j;
  char zTempPath[MAX_PATH+1];
  if( sqlite3_temp_directory ){

/*
** Turn a relative pathname into a full pathname.  Write the full
** pathname into zOut[].  zOut[] will be at least pVfs->mxPathname
** bytes in size.
*/
static int winFullPathname(
  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
  const char *zRelative,        /* Possibly relative input path */
  int nFull,                    /* Size of output buffer in bytes */
  char *zFull                   /* Output buffer */
){

#if defined(__CYGWIN__)
  cygwin_conv_to_full_win32_path(zRelative, zFull);
  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 1.390 2007/09/17 07:02:57 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*

  char *zPathname;
  int nPathname;

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

  /* Compute the full pathname */
  nPathname = pVfs->mxPathname+1;
  zPathname = sqlite3_malloc(nPathname);
  if( zPathname==0 ){
    return SQLITE_NOMEM;
  }
  if( zFilename && zFilename[0] ){
#ifndef SQLITE_OMIT_MEMORYDB
    if( strcmp(zFilename,":memory:")==0 ){
      memDb = 1;
      zPathname[0] = 0;
    }else
#endif
    {
      rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
    }
  }else{
    rc = sqlite3OsGetTempname(pVfs, nPathname, zPathname);
  }
  if( rc!=SQLITE_OK ){
    sqlite3_free(zPathname);
    return rc;
  }
  nPathname = strlen(zPathname);

** 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 1.261 2007/09/17 07:02:57 danielk1977 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++.

** to test for the existance of a file,
** or [SQLITE_ACCESS_READWRITE] to test to see
** if a file is readable and writable, or [SQLITE_ACCESS_READ]
** to test to see if a file is at least readable.  The file can be a 
** directory.
** 
** SQLite will always allocate at least mxPathname+1 byte for
** the output buffers for xGetTempname and xFullPathname. The exact
** size of the output buffer is also passed as a parameter to both 
** methods. If the output buffer is not large enough, SQLITE_CANTOPEN
** should be returned. As this is handled as a fatal error by SQLite,
** vfs implementations should endevour to prevent this by setting 
** mxPathname to a sufficiently large value.
** 
** The xRandomness(), xSleep(), and xCurrentTime() interfaces
** are not strictly a part of the filesystem, but they are
** included in the VFS structure for completeness.
** The xRandomness() function attempts to return nBytes bytes
** of good-quality randomness into zOut.  The return value is
** the actual number of bytes of randomness obtained.  The

  sqlite3_vfs *pNext;      /* Next registered VFS */
  const char *zName;       /* Name of this virtual file system */
  void *pAppData;          /* Pointer to application-specific data */
  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*, int nOut, char *zOut);
  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
  void *(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol);
  void (*xDlClose)(sqlite3_vfs*, void*);
  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
  int (*xSleep)(sqlite3_vfs*, int microseconds);
  int (*xCurrentTime)(sqlite3_vfs*, double*);

  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xDelete(pVfs, zPath, dirSync);
}
static int cfAccess(sqlite3_vfs *pCfVfs, const char *zPath, int flags){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xAccess(pVfs, zPath, flags);
}
static int cfGetTempname(sqlite3_vfs *pCfVfs, int nBufOut, char *zBufOut){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xGetTempname(pVfs, nBufOut, zBufOut);
}
static int cfFullPathname(
  sqlite3_vfs *pCfVfs, 
  const char *zPath, 
  int nPathOut,
  char *zPathOut
){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
}
static void *cfDlOpen(sqlite3_vfs *pCfVfs, const char *zPath){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
  return pVfs->xDlOpen(pVfs, zPath);
}
static void cfDlError(sqlite3_vfs *pCfVfs, int nByte, char *zErrMsg){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;

    flags==SQLITE_ACCESS_READ?"read":"exists"
    , zName, ret)
  );
  pthread_mutex_unlock(&async.queueMutex);
  return ret;
}

static int asyncGetTempname(sqlite3_vfs *pAsyncVfs, int nBufOut, char *zBufOut){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pAsyncVfs->pAppData;
  return pVfs->xGetTempname(pVfs, nBufOut, zBufOut);
}

/*
** Fill in zPathOut with the full path to the file identified by zPath.
*/
static int asyncFullPathname(
  sqlite3_vfs *pAsyncVfs, 
  const char *zPath, 
  int nPathOut,
  char *zPathOut
){
  int rc;
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pAsyncVfs->pAppData;
  rc = sqlite3OsFullPathname(pVfs, zPath, nPathOut, zPathOut);

  /* Because of the way intra-process file locking works, this backend
  ** needs to return a canonical path. The following block assumes the
  ** file-system uses unix style paths. 
  */
  if( rc==SQLITE_OK ){
    int iIn;

/*
** Method declarations for fs_vfs.
*/
static int fsOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int fsDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int fsAccess(sqlite3_vfs*, const char *zName, int flags);
static int fsGetTempname(sqlite3_vfs*, int nOut, char *zOut);
static int fsFullPathname(sqlite3_vfs*, const char *zName, int nOut,char *zOut);
static void *fsDlOpen(sqlite3_vfs*, const char *zFilename);
static void fsDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void *fsDlSym(sqlite3_vfs*,void*, const char *zSymbol);
static void fsDlClose(sqlite3_vfs*, void*);
static int fsRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int fsSleep(sqlite3_vfs*, int microseconds);
static int fsCurrentTime(sqlite3_vfs*, double*);

}

/*
** Populate buffer zBufOut with a pathname suitable for use as a 
** temporary file. zBufOut is guaranteed to point to a buffer of 
** at least (FS_MAX_PATHNAME+1) bytes.
*/
static int fsGetTempname(sqlite3_vfs *pVfs, int nBufOut, char *zBufOut){
  sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
  return pParent->xGetTempname(pParent, nBufOut, zBufOut);
}

/*
** Populate buffer zOut with the full canonical pathname corresponding
** to the pathname in zPath. zOut is guaranteed to point to a buffer
** of at least (FS_MAX_PATHNAME+1) bytes.
*/
static int fsFullPathname(
  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
  const char *zPath,            /* Possibly relative input path */
  int nOut,                     /* Size of output buffer in bytes */
  char *zOut                    /* Output buffer */
){
  sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
  return pParent->xFullPathname(pParent, zPath, nOut, zOut);
}

/*
** Open the dynamic library located at zPath and return a handle.
*/
static void *fsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
  sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;