SQLite

  u8 noReadlock;              /* Do not bother to obtain readlocks */
  u8 noSync;                  /* Do not sync the journal if true */
  u8 fullSync;                /* Do extra syncs of the journal for robustness */
  u8 sync_flags;              /* One of SYNC_NORMAL or SYNC_FULL */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 memDb;                   /* True to inhibit all file I/O */
  u8 safeJrnlHandle;          /* True if jrnl may be held open with no lock */

  /* The following block contains those class members that are dynamically
  ** modified during normal operations. The other variables in this structure
  ** are either constant throughout the lifetime of the pager, or else
  ** used to store configuration parameters that affect the way the pager 
  ** operates.
  **

  if( !pPager->exclusiveMode ){
    int rc = SQLITE_OK;          /* Return code */

    /* Always close the journal file when dropping the database lock.
    ** Otherwise, another connection with journal_mode=delete might
    ** delete the file out from under us.
    */
    if( pPager->safeJrnlHandle==0 
     || (pPager->journalMode!=PAGER_JOURNALMODE_TRUNCATE 
      && pPager->journalMode!=PAGER_JOURNALMODE_PERSIST)
    ){
      sqlite3OsClose(pPager->jfd);
    }

    sqlite3BitvecDestroy(pPager->pInJournal);
    pPager->pInJournal = 0;
    releaseAllSavepoints(pPager);

    /* If the file is unlocked, somebody else might change it. The
    ** values stored in Pager.dbSize etc. might become invalid if
    ** this happens.  One can argue that this doesn't need to be cleared

int sqlite3PagerClose(Pager *pPager){
  u8 *pTmp = (u8 *)pPager->pTmpSpace;

  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  pPager->errCode = 0;
  pPager->exclusiveMode = 0;
  pPager->safeJrnlHandle = 0;
#ifndef SQLITE_OMIT_WAL
  sqlite3WalClose(pPager->pWal,
    (pPager->noSync ? 0 : pPager->sync_flags), 
    pPager->pageSize, pTmp
  );
  pPager->pWal = 0;
#endif

** SQLITE_OK returned. If no hot-journal file is present, *pExists is
** set to 0 and SQLITE_OK returned. If an IO error occurs while trying
** to determine whether or not a hot-journal file exists, the IO error
** code is returned and the value of *pExists is undefined.
*/
static int hasHotJournal(Pager *pPager, int *pExists){
  sqlite3_vfs * const pVfs = pPager->pVfs;
  int rc = SQLITE_OK;           /* Return code */
  int exists = 1;               /* True if a journal file is present */
  int jrnlOpen = !!isOpen(pPager->jfd);

  assert( pPager!=0 );
  assert( pPager->useJournal );
  assert( isOpen(pPager->fd) );

  assert( pPager->state <= PAGER_SHARED );
  assert( jrnlOpen==0
       || sqlite3OsDeviceCharacteristics(pPager->jfd)&SQLITE_IOCAP_SAFE_DELETE
  );

  *pExists = 0;
  if( !jrnlOpen ){
    rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &exists);
  }
  if( rc==SQLITE_OK && exists ){
    int locked;                 /* True if some process holds a RESERVED lock */

    /* Race condition here:  Another process might have been holding the
    ** the RESERVED lock and have a journal open at the sqlite3OsAccess() 
    ** call above, but then delete the journal and drop the lock before
    ** we get to the following sqlite3OsCheckReservedLock() call.  If that

        }else{
          /* The journal file exists and no other connection has a reserved
          ** or greater lock on the database file. Now check that there is
          ** at least one non-zero bytes at the start of the journal file.
          ** If there is, then we consider this journal to be hot. If not, 
          ** it can be ignored.
          */
          if( !jrnlOpen ){
            int f = SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL;
            rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &f);
          }
          if( rc==SQLITE_OK ){
            u8 first = 0;
            rc = sqlite3OsRead(pPager->jfd, (void *)&first, 1, 0);
            if( rc==SQLITE_IOERR_SHORT_READ ){
              rc = SQLITE_OK;
            }
            if( !jrnlOpen ){
              sqlite3OsClose(pPager->jfd);
            }
            *pExists = (first!=0);
          }else if( rc==SQLITE_CANTOPEN ){
            /* If we cannot open the rollback journal file in order to see if
            ** its has a zero header, that might be due to an I/O error, or
            ** it might be due to the race condition described above and in
            ** ticket #3883.  Either way, assume that the journal is hot.
            ** This might be a false positive.  But if it is, then the

        );
#ifdef SQLITE_ENABLE_ATOMIC_WRITE
      rc = sqlite3JournalOpen(
          pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
      );
#else
      rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
      if( rc==SQLITE_OK ){
        int iDc = sqlite3OsDeviceCharacteristics(pPager->jfd);
        pPager->safeJrnlHandle = (iDc&SQLITE_IOCAP_SAFE_DELETE)!=0;
      }
#endif
    }
    assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
  }


  /* Write the first journal header to the journal file and open 

#define SQLITE_IOCAP_ATOMIC4K        0x00000010
#define SQLITE_IOCAP_ATOMIC8K        0x00000020
#define SQLITE_IOCAP_ATOMIC16K       0x00000040
#define SQLITE_IOCAP_ATOMIC32K       0x00000080
#define SQLITE_IOCAP_ATOMIC64K       0x00000100
#define SQLITE_IOCAP_SAFE_APPEND     0x00000200
#define SQLITE_IOCAP_SEQUENTIAL      0x00000400
#define SQLITE_IOCAP_SAFE_DELETE     0x00000800

/*
** CAPI3REF: File Locking Levels
**
** SQLite uses one of these integer values as the second
** argument to calls it makes to the xLock() and xUnlock() methods
** of an [sqlite3_io_methods] object.

  TestvfsBuffer *pBuffer;         /* List of shared buffers */
  int isNoshm;

  int mask;
  int iIoerrCnt;
  int ioerr;
  int nIoerrFail;

  int iDevchar;
  int iSectorsize;
};

/*
** The Testvfs.mask variable is set to a combination of the following.
** If a bit is clear in Testvfs.mask, then calls made by SQLite to the 
** corresponding VFS method is ignored for purposes of:
**
**   + Simulating IO errors, and
**   + Invoking the Tcl callback script.
*/
#define TESTVFS_SHMOPEN_MASK    0x00000001
#define TESTVFS_SHMLOCK_MASK    0x00000010
#define TESTVFS_SHMMAP_MASK     0x00000020
#define TESTVFS_SHMBARRIER_MASK 0x00000040
#define TESTVFS_SHMCLOSE_MASK   0x00000080

#define TESTVFS_OPEN_MASK       0x00000100
#define TESTVFS_SYNC_MASK       0x00000200
#define TESTVFS_DELETE_MASK     0x00000400
#define TESTVFS_CLOSE_MASK      0x00000800
#define TESTVFS_WRITE_MASK      0x00001000
#define TESTVFS_TRUNCATE_MASK   0x00002000
#define TESTVFS_ALL_MASK        0x00003FFF


#define TESTVFS_MAX_PAGES 256

/*
** A shared-memory buffer. There is one of these objects for each shared
** memory region opened by clients. If two clients open the same file,

}


/*
** Close an tvfs-file.
*/
static int tvfsClose(sqlite3_file *pFile){
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;

  if( p->pScript && p->mask&TESTVFS_CLOSE_MASK ){
    tvfsExecTcl(p, "xClose", 
        Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId, 0
    );
  }

  if( pFd->pShmId ){
    Tcl_DecrRefCount(pFd->pShmId);
    pFd->pShmId = 0;
  }
  if( pFile->pMethods ){
    ckfree((char *)pFile->pMethods);
  }
  return sqlite3OsClose(pFd->pReal);
}

/*
** Read data from an tvfs-file.
*/
static int tvfsRead(
  sqlite3_file *pFile, 

*/
static int tvfsWrite(
  sqlite3_file *pFile, 
  const void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  int rc = SQLITE_OK;
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;

  if( p->pScript && p->mask&TESTVFS_WRITE_MASK ){
    tvfsExecTcl(p, "xWrite", 
        Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId, 0
    );
    tvfsResultCode(p, &rc);
  }
  
  if( rc==SQLITE_OK ){
    rc = sqlite3OsWrite(pFd->pReal, zBuf, iAmt, iOfst);
  }
  return rc;
}

/*
** Truncate an tvfs-file.
*/
static int tvfsTruncate(sqlite3_file *pFile, sqlite_int64 size){
  int rc = SQLITE_OK;
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;

  if( p->pScript && p->mask&TESTVFS_TRUNCATE_MASK ){
    tvfsExecTcl(p, "xTruncate", 
        Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId, 0
    );
    tvfsResultCode(p, &rc);
  }
  
  if( rc==SQLITE_OK ){
    rc = sqlite3OsTruncate(pFd->pReal, size);
  }
  return rc;
}

/*
** Sync an tvfs-file.
*/
static int tvfsSync(sqlite3_file *pFile, int flags){
  int rc = SQLITE_OK;

  return sqlite3OsFileControl(p->pReal, op, pArg);
}

/*
** Return the sector-size in bytes for an tvfs-file.
*/
static int tvfsSectorSize(sqlite3_file *pFile){
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
  if( p->iSectorsize>=0 ){
    return p->iSectorsize;
  }
  return sqlite3OsSectorSize(pFd->pReal);
}

/*
** Return the device characteristic flags supported by an tvfs-file.
*/
static int tvfsDeviceCharacteristics(sqlite3_file *pFile){
  TestvfsFile *pFd = (TestvfsFile *)pFile;
  Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
  if( p->iDevchar>=0 ){
    return p->iDevchar;
  }
  return sqlite3OsDeviceCharacteristics(pFd->pReal);
}

/*
** Open an tvfs file handle.
*/
static int tvfsOpen(
  sqlite3_vfs *pVfs,

  ClientData cd,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  Testvfs *p = (Testvfs *)cd;




  enum DB_enum { 
    CMD_SHM, CMD_DELETE, CMD_FILTER, CMD_IOERR, CMD_SCRIPT, 
    CMD_DEVCHAR, CMD_SECTORSIZE
  };
  struct TestvfsSubcmd {
    char *zName;
    enum DB_enum eCmd;
  } aSubcmd[] = {
    { "shm",        CMD_SHM        },
    { "delete",     CMD_DELETE     },
    { "filter",     CMD_FILTER     },
    { "ioerr",      CMD_IOERR      },
    { "script",     CMD_SCRIPT     },
    { "devchar",    CMD_DEVCHAR    },
    { "sectorsize", CMD_SECTORSIZE },
    { 0, 0 }
  };
  int i;
  
  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUBCOMMAND ...");
    return TCL_ERROR;
  }
  if( Tcl_GetIndexFromObjStruct(
        interp, objv[1], aSubcmd, sizeof(aSubcmd[0]), "subcommand", 0, &i) 
  ){
    return TCL_ERROR;
  }
  Tcl_ResetResult(interp);

  switch( aSubcmd[i].eCmd ){
    case CMD_SHM: {
      Tcl_Obj *pObj;
      int i;
      TestvfsBuffer *pBuffer;
      char *zName;
      if( objc!=3 && objc!=4 ){
        Tcl_WrongNumArgs(interp, 2, objv, "FILE ?VALUE?");

        { "xShmOpen",    TESTVFS_SHMOPEN_MASK },
        { "xShmLock",    TESTVFS_SHMLOCK_MASK },
        { "xShmBarrier", TESTVFS_SHMBARRIER_MASK },
        { "xShmClose",   TESTVFS_SHMCLOSE_MASK },
        { "xShmMap",     TESTVFS_SHMMAP_MASK },
        { "xSync",       TESTVFS_SYNC_MASK },
        { "xDelete",     TESTVFS_DELETE_MASK },
        { "xWrite",      TESTVFS_WRITE_MASK },
        { "xTruncate",   TESTVFS_TRUNCATE_MASK },
        { "xOpen",       TESTVFS_OPEN_MASK },
        { "xClose",      TESTVFS_CLOSE_MASK },
      };
      Tcl_Obj **apElem = 0;
      int nElem = 0;
      int i;
      int mask = 0;
      if( objc!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "LIST");

      break;
    }

    case CMD_DELETE: {
      Tcl_DeleteCommand(interp, Tcl_GetString(objv[0]));
      break;
    }

    case CMD_DEVCHAR: {
      struct DeviceFlag {
        char *zName;
        int iValue;
      } aFlag[] = {
        { "default",     -1 },
        { "atomic",      SQLITE_IOCAP_ATOMIC      },
        { "atomic512",   SQLITE_IOCAP_ATOMIC512   },
        { "atomic1k",    SQLITE_IOCAP_ATOMIC1K    },
        { "atomic2k",    SQLITE_IOCAP_ATOMIC2K    },
        { "atomic4k",    SQLITE_IOCAP_ATOMIC4K    },
        { "atomic8k",    SQLITE_IOCAP_ATOMIC8K    },
        { "atomic16k",   SQLITE_IOCAP_ATOMIC16K   },
        { "atomic32k",   SQLITE_IOCAP_ATOMIC32K   },
        { "atomic64k",   SQLITE_IOCAP_ATOMIC64K   },
        { "sequential",  SQLITE_IOCAP_SEQUENTIAL  },
        { "safe_append", SQLITE_IOCAP_SAFE_APPEND },
        { "safe_delete", SQLITE_IOCAP_SAFE_DELETE },
        { 0, 0 }
      };
      Tcl_Obj *pRet;
      int iFlag;

      if( objc>3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "?ATTR-LIST?");
        return TCL_ERROR;
      }
      if( objc==3 ){
        int j;
        int iNew = 0;
        Tcl_Obj **flags = 0;
        int nFlags = 0;

        if( Tcl_ListObjGetElements(interp, objv[2], &nFlags, &flags) ){
          return TCL_ERROR;
        }

        for(j=0; j<nFlags; j++){
          int idx = 0;
          if( Tcl_GetIndexFromObjStruct(interp, flags[j], aFlag, 
                sizeof(aFlag[0]), "flag", 0, &idx) 
          ){
            return TCL_ERROR;
          }
          if( aFlag[idx].iValue<0 && nFlags>1 ){
            Tcl_AppendResult(interp, "bad flags: ", Tcl_GetString(objv[2]), 0);
            return TCL_ERROR;
          }
          iNew |= aFlag[idx].iValue;
        }

        p->iDevchar = iNew;
      }

      pRet = Tcl_NewObj();
      for(iFlag=0; iFlag<sizeof(aFlag)/sizeof(aFlag[0]); iFlag++){
        if( p->iDevchar & aFlag[iFlag].iValue ){
          Tcl_ListObjAppendElement(
              interp, pRet, Tcl_NewStringObj(aFlag[iFlag].zName, -1)
          );
        }
      }
      Tcl_SetObjResult(interp, pRet);

      break;
    }

    case CMD_SECTORSIZE: {
      if( objc>3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "?VALUE?");
        return TCL_ERROR;
      }
      if( objc==3 ){
        int iNew = 0;
        if( Tcl_GetIntFromObj(interp, objv[2], &iNew) ){
          return TCL_ERROR;
        }
        p->iSectorsize = iNew;
      }
      Tcl_SetObjResult(interp, Tcl_NewIntObj(p->iSectorsize));
      break;
    }
  }

  return TCL_OK;
}

static void testvfs_obj_del(ClientData cd){
  Testvfs *p = (Testvfs *)cd;

    }
  }

  zVfs = Tcl_GetString(objv[1]);
  nByte = sizeof(Testvfs) + strlen(zVfs)+1;
  p = (Testvfs *)ckalloc(nByte);
  memset(p, 0, nByte);
  p->iDevchar = -1;
  p->iSectorsize = -1;

  /* Create the new object command before querying SQLite for a default VFS
  ** to use for 'real' IO operations. This is because creating the new VFS
  ** may delete an existing [testvfs] VFS of the same name. If such a VFS
  ** is currently the default, the new [testvfs] may end up calling the 
  ** methods of a deleted object.
  */

# 2010 June 16
#
# 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.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
db close

set a_string_counter 1
proc a_string {n} {
  global a_string_counter
  incr a_string_counter
  string range [string repeat "${a_string_counter}." $n] 1 $n
}

# Create a [testvfs] and install it as the default VFS. Set the device
# characteristics flags to "SAFE_DELETE".
#
testvfs tvfs -default 1
tvfs devchar safe_delete

# Set up a hook so that each time a journal file is opened, closed or
# deleted, the method name ("xOpen", "xClose" or "xDelete") and the final
# segment of the journal file-name (i.e. "test.db-journal") are appended to
# global list variable $::oplog.
#
tvfs filter {xOpen xClose xDelete}
tvfs script journal_op_catcher

proc journal_op_catcher {method filename args} {

  # If global variable ::tvfs_error_on_write is defined, then return an
  # IO error to every attempt to modify the file-system. Otherwise, return
  # SQLITE_OK.
  #
  if {[info exists ::tvfs_error_on_write]} {
    if {$method == "xDelete" || $method == "xWrite" || $method == "xTruncate"} {
      return SQLITE_IOERR 
    }
    return SQLITE_OK
  }

  if {[string match *journal* $filename]==0} return

  set f [file tail $filename]
  lappend ::oplog $method $f

  if {[info exists ::open_journals($f)]==0} { set ::open_journals($f) 0 }
  switch -- $method {
    xOpen {
      incr ::open_journals($f) +1
    }
    xClose {
      incr ::open_journals($f) -1
    }
    xDelete {
      if {$::open_journals($f)>0} { return SQLITE_IOERR }
    }
  }

  return
}


do_test journal2-1.1 {
  set ::oplog [list]
  sqlite3 db test.db
  execsql { CREATE TABLE t1(a, b) }
  set ::oplog
} {xOpen test.db-journal xClose test.db-journal xDelete test.db-journal}
do_test journal2-1.2 {
  set ::oplog [list]
  execsql { 
    PRAGMA journal_mode = truncate;
    INSERT INTO t1 VALUES(1, 2);
  }
  set ::oplog
} {xOpen test.db-journal}
do_test journal2-1.3 {
  set ::oplog [list]
  execsql { INSERT INTO t1 VALUES(3, 4) }
  set ::oplog
} {}
do_test journal2-1.4 { execsql { SELECT * FROM t1 } } {1 2 3 4}

# Add a second connection. This connection attempts to commit data in
# journal_mode=DELETE mode. When it tries to delete the journal file,
# the VFS layer returns an IO error.
#
do_test journal2-1.5 {
  set ::oplog [list]
  sqlite3 db2 test.db
  execsql  { PRAGMA journal_mode = delete } db2
  catchsql { INSERT INTO t1 VALUES(5, 6)  } db2
} {1 {disk I/O error}}
do_test journal2-1.6 { file exists test.db-journal } 1
do_test journal2-1.7 { execsql { SELECT * FROM t1 } } {1 2 3 4}
do_test journal2-1.8 {
  execsql { PRAGMA journal_mode = truncate } db2
  execsql { INSERT INTO t1 VALUES(5, 6)  } db2
} {}
do_test journal2-1.9 { execsql { SELECT * FROM t1 } } {1 2 3 4 5 6}

# Grow the database until it is reasonably large. Then, from a 
# journal_mode=DELETE connection, attempt to commit a large transaction (one
# that involves upgrading to an exclusive lock and writing the database
# before the transaction is committed).
#
do_test journal2-1.10 {
  db2 close
  db func a_string a_string
  execsql {
    CREATE TABLE t2(a UNIQUE, b UNIQUE);
    INSERT INTO t2 VALUES(a_string(200), a_string(300));
    INSERT INTO t2 SELECT a_string(200), a_string(300) FROM t2;  --  2
    INSERT INTO t2 SELECT a_string(200), a_string(300) FROM t2;  --  4
    INSERT INTO t2 SELECT a_string(200), a_string(300) FROM t2;  --  8
    INSERT INTO t2 SELECT a_string(200), a_string(300) FROM t2;  -- 16
    INSERT INTO t2 SELECT a_string(200), a_string(300) FROM t2;  -- 32
    INSERT INTO t2 SELECT a_string(200), a_string(300) FROM t2;  -- 64
  }
  file size test.db-journal
} {0}
do_test journal2-1.11 {
  set sz [expr [file size test.db] / 1024]
  expr {$sz>120 && $sz<200}
} 1

do_test journal2-1.12 {
  sqlite3 db2 test.db
  execsql {
    PRAGMA cache_size = 10;
    BEGIN;
      INSERT INTO t2 SELECT randomblob(200), randomblob(300) FROM t2;  -- 128
  } db2
} {}
do_test journal2-1.13 {
  tvfs filter {xOpen xClose xDelete xWrite xTruncate}
  set ::tvfs_error_on_write 1
  catchsql { COMMIT } db2
} {1 {disk I/O error}}
db2 close
unset ::tvfs_error_on_write
file copy -force test.db testX.db

do_test journal2-1.14 { file exists test.db-journal } 1
do_test journal2-1.15 {
  execsql {
    SELECT count(*) FROM t2;
    PRAGMA integrity_check;
  }
} {64 ok}

# This block checks that in the test case above, connection [db2] really
# did begin writing to the database file before it hit IO errors. If
# this is true, then the copy of the database file made before [db]
# rolled back the hot journal should fail the integrity-check.
#
do_test journal2-1.16 {
  set sz [expr [file size testX.db] / 1024]
  expr {$sz>240 && $sz<400}
} 1
do_test journal2-1.17 {
  expr {[catchsql { PRAGMA integrity_check } db] == "0 ok"}
} {1}
do_test journal2-1.20 {
  sqlite3 db2 testX.db
  expr {[catchsql { PRAGMA integrity_check } db2] == "0 ok"}
} {0}
do_test journal2-1.21 {
  db2 close
} {}

db close
tvfs delete
finish_test