third_party/sqlite/src/src/test

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
enterJtMutex
leaveJtMutex
stop_ioerr_simulation
start_ioerr_simulation
closeTransaction
jtClose
jtRead
locateDatabaseHandle
decodeUint32
genCksum
decodeJournalHdr
openTransaction
readJournalFile
jtWrite
jtTruncate
jtSync
jtFileSize
jtLock
jtUnlock
jtCheckReservedLock
jtFileControl
jtSectorSize
jtDeviceCharacteristics
jtOpen
jtDelete
jtAccess
jtFullPathname
jtDlOpen
jtDlError
jtDlSym
jtDlClose
jtRandomness
jtSleep
jtCurrentTime
jtCurrentTimeInt64
jt_register
jt_unregister
/*
** 2008 Jan 22
**
** 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 contains code for a VFS layer that acts as a wrapper around
** an existing VFS. The code in this file attempts to verify that SQLite
** correctly populates and syncs a journal file before writing to a
** corresponding database file.
*/
#if SQLITE_TEST          /* This file is used for testing only */

#include "sqlite3.h"
#include "sqliteInt.h"

/*
** INTERFACE
**
**   The public interface to this wrapper VFS is two functions:
**
**     jt_register()
**     jt_unregister()
**
**   See header comments associated with those two functions below for 
**   details.
**
** LIMITATIONS
**
**   This wrapper will not work if "PRAGMA synchronous = off" is used.
**
** OPERATION
**
**  Starting a Transaction:
**
**   When a write-transaction is started, the contents of the database is
**   inspected and the following data stored as part of the database file 
**   handle (type struct jt_file):
**
**     a) The page-size of the database file.
**     b) The number of pages that are in the database file.
**     c) The set of page numbers corresponding to free-list leaf pages.
**     d) A check-sum for every page in the database file.
**
**   The start of a write-transaction is deemed to have occurred when a 
**   28-byte journal header is written to byte offset 0 of the journal 
**   file.
**
**  Syncing the Journal File:
**
**   Whenever the xSync method is invoked to sync a journal-file, the
**   contents of the journal file are read. For each page written to
**   the journal file, a check-sum is calculated and compared to the  
**   check-sum calculated for the corresponding database page when the
**   write-transaction was initialized. The success of the comparison
**   is assert()ed. So if SQLite has written something other than the
**   original content to the database file, an assert() will fail.
**
**   Additionally, the set of page numbers for which records exist in
**   the journal file is added to (unioned with) the set of page numbers
**   corresponding to free-list leaf pages collected when the 
**   write-transaction was initialized. This set comprises the page-numbers 
**   corresponding to those pages that SQLite may now safely modify.
**
**  Writing to the Database File:
**
**   When a block of data is written to a database file, the following
**   invariants are asserted:
**
**     a) That the block of data is an aligned block of page-size bytes.
**
**     b) That if the page being written did not exist when the 
**        transaction was started (i.e. the database file is growing), then
**        the journal-file must have been synced at least once since
**        the start of the transaction.
**
**     c) That if the page being written did exist when the transaction 
**        was started, then the page must have either been a free-list
**        leaf page at the start of the transaction, or else must have
**        been stored in the journal file prior to the most recent sync.
**
**  Closing a Transaction:
**
**   When a transaction is closed, all data collected at the start of
**   the transaction, or following an xSync of a journal-file, is 
**   discarded. The end of a transaction is recognized when any one 
**   of the following occur:
**
**     a) A block of zeroes (or anything else that is not a valid 
**        journal-header) is written to the start of the journal file.
**
**     b) A journal file is truncated to zero bytes in size using xTruncate.
**
**     c) The journal file is deleted using xDelete.
*/

/*
** Maximum pathname length supported by the jt backend.
*/
#define JT_MAX_PATHNAME 512

/*
** Name used to identify this VFS.
*/
#define JT_VFS_NAME "jt"

typedef struct jt_file jt_file;
struct jt_file {
  sqlite3_file base;
  const char *zName;       /* Name of open file */
  int flags;               /* Flags the file was opened with */

  /* The following are only used by database file file handles */
  int eLock;               /* Current lock held on the file */
  u32 nPage;               /* Size of file in pages when transaction started */
  u32 nPagesize;           /* Page size when transaction started */
  Bitvec *pWritable;       /* Bitvec of pages that may be written to the file */
  u32 *aCksum;             /* Checksum for first nPage pages */
  int nSync;               /* Number of times journal file has been synced */

  /* Only used by journal file-handles */
  sqlite3_int64 iMaxOff;   /* Maximum offset written to this transaction */

  jt_file *pNext;          /* All files are stored in a linked list */
  sqlite3_file *pReal;     /* The file handle for the underlying vfs */
};

/*
** Method declarations for jt_file.
*/
static int jtClose(sqlite3_file*);
static int jtRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int jtWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
static int jtTruncate(sqlite3_file*, sqlite3_int64 size);
static int jtSync(sqlite3_file*, int flags);
static int jtFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int jtLock(sqlite3_file*, int);
static int jtUnlock(sqlite3_file*, int);
static int jtCheckReservedLock(sqlite3_file*, int *);
static int jtFileControl(sqlite3_file*, int op, void *pArg);
static int jtSectorSize(sqlite3_file*);
static int jtDeviceCharacteristics(sqlite3_file*);

/*
** Method declarations for jt_vfs.
*/
static int jtOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int jtDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int jtAccess(sqlite3_vfs*, const char *zName, int flags, int *);
static int jtFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
static void *jtDlOpen(sqlite3_vfs*, const char *zFilename);
static void jtDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void (*jtDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
static void jtDlClose(sqlite3_vfs*, void*);
static int jtRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int jtSleep(sqlite3_vfs*, int microseconds);
static int jtCurrentTime(sqlite3_vfs*, double*);
static int jtCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);

static sqlite3_vfs jt_vfs = {
  2,                             /* iVersion */
  sizeof(jt_file),               /* szOsFile */
  JT_MAX_PATHNAME,               /* mxPathname */
  0,                             /* pNext */
  JT_VFS_NAME,                   /* zName */
  0,                             /* pAppData */
  jtOpen,                        /* xOpen */
  jtDelete,                      /* xDelete */
  jtAccess,                      /* xAccess */
  jtFullPathname,                /* xFullPathname */
  jtDlOpen,                      /* xDlOpen */
  jtDlError,                     /* xDlError */
  jtDlSym,                       /* xDlSym */
  jtDlClose,                     /* xDlClose */
  jtRandomness,                  /* xRandomness */
  jtSleep,                       /* xSleep */
  jtCurrentTime,                 /* xCurrentTime */
  0,                             /* xGetLastError */
  jtCurrentTimeInt64             /* xCurrentTimeInt64 */
};

static sqlite3_io_methods jt_io_methods = {
  1,                             /* iVersion */
  jtClose,                       /* xClose */
  jtRead,                        /* xRead */
  jtWrite,                       /* xWrite */
  jtTruncate,                    /* xTruncate */
  jtSync,                        /* xSync */
  jtFileSize,                    /* xFileSize */
  jtLock,                        /* xLock */
  jtUnlock,                      /* xUnlock */
  jtCheckReservedLock,           /* xCheckReservedLock */
  jtFileControl,                 /* xFileControl */
  jtSectorSize,                  /* xSectorSize */
  jtDeviceCharacteristics        /* xDeviceCharacteristics */
};

struct JtGlobal {
  sqlite3_vfs *pVfs;             /* Parent VFS */
  jt_file *pList;                /* List of all open files */
};
static struct JtGlobal g = {0, 0};

/*
** Functions to obtain and relinquish a mutex to protect g.pList. The
** STATIC_PRNG mutex is reused, purely for the sake of convenience.
*/
static void enterJtMutex(void){
  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PRNG));
}
static void leaveJtMutex(void){
  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PRNG));
}

extern int sqlite3_io_error_pending;
extern int sqlite3_io_error_hit;
static void stop_ioerr_simulation(int *piSave, int *piSave2){
  *piSave = sqlite3_io_error_pending;
  *piSave2 = sqlite3_io_error_hit;
  sqlite3_io_error_pending = -1;
  sqlite3_io_error_hit = 0;
}
static void start_ioerr_simulation(int iSave, int iSave2){
  sqlite3_io_error_pending = iSave;
  sqlite3_io_error_hit = iSave2;
}

/*
** The jt_file pointed to by the argument may or may not be a file-handle
** open on a main database file. If it is, and a transaction is currently
** opened on the file, then discard all transaction related data.
*/
static void closeTransaction(jt_file *p){
  sqlite3BitvecDestroy(p->pWritable);
  sqlite3_free(p->aCksum);
  p->pWritable = 0;
  p->aCksum = 0;
  p->nSync = 0;
}

/*
** Close an jt-file.
*/
static int jtClose(sqlite3_file *pFile){
  jt_file **pp;
  jt_file *p = (jt_file *)pFile;

  closeTransaction(p);
  enterJtMutex();
  if( p->zName ){
    for(pp=&g.pList; *pp!=p; pp=&(*pp)->pNext);
    *pp = p->pNext;
  }
  leaveJtMutex();
  return sqlite3OsClose(p->pReal);
}

/*
** Read data from an jt-file.
*/
static int jtRead(
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  jt_file *p = (jt_file *)pFile;
  return sqlite3OsRead(p->pReal, zBuf, iAmt, iOfst);
}

/*
** Parameter zJournal is the name of a journal file that is currently 
** open. This function locates and returns the handle opened on the
** corresponding database file by the pager that currently has the
** journal file opened. This file-handle is identified by the 
** following properties:
**
**   a) SQLITE_OPEN_MAIN_DB was specified when the file was opened.
**
**   b) The file-name specified when the file was opened matches
**      all but the final 8 characters of the journal file name.
**
**   c) There is currently a reserved lock on the file.
**/
static jt_file *locateDatabaseHandle(const char *zJournal){
  jt_file *pMain = 0;
  enterJtMutex();
  for(pMain=g.pList; pMain; pMain=pMain->pNext){
    int nName = strlen(zJournal) - strlen("-journal");
    if( (pMain->flags&SQLITE_OPEN_MAIN_DB)
     && (strlen(pMain->zName)==nName)
     && 0==memcmp(pMain->zName, zJournal, nName)
     && (pMain->eLock>=SQLITE_LOCK_RESERVED)
    ){
      break;
    }
  }
  leaveJtMutex();
  return pMain;
}

/*
** Parameter z points to a buffer of 4 bytes in size containing a 
** unsigned 32-bit integer stored in big-endian format. Decode the 
** integer and return its value.
*/
static u32 decodeUint32(const unsigned char *z){
  return (z[0]<<24) + (z[1]<<16) + (z[2]<<8) + z[3];
}

/*
** Calculate a checksum from the buffer of length n bytes pointed to
** by parameter z.
*/
static u32 genCksum(const unsigned char *z, int n){
  int i;
  u32 cksum = 0;
  for(i=0; i<n; i++){
    cksum = cksum + z[i] + (cksum<<3);
  }
  return cksum;
}

/*
** The first argument, zBuf, points to a buffer containing a 28 byte
** serialized journal header. This function deserializes four of the
** integer fields contained in the journal header and writes their
** values to the output variables.
**
** SQLITE_OK is returned if the journal-header is successfully 
** decoded. Otherwise, SQLITE_ERROR.
*/
static int decodeJournalHdr(
  const unsigned char *zBuf,         /* Input: 28 byte journal header */
  u32 *pnRec,                        /* Out: Number of journalled records */
  u32 *pnPage,                       /* Out: Original database page count */
  u32 *pnSector,                     /* Out: Sector size in bytes */
  u32 *pnPagesize                    /* Out: Page size in bytes */
){
  unsigned char aMagic[] = { 0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7 };
  if( memcmp(aMagic, zBuf, 8) ) return SQLITE_ERROR;
  if( pnRec ) *pnRec = decodeUint32(&zBuf[8]);
  if( pnPage ) *pnPage = decodeUint32(&zBuf[16]);
  if( pnSector ) *pnSector = decodeUint32(&zBuf[20]);
  if( pnPagesize ) *pnPagesize = decodeUint32(&zBuf[24]);
  return SQLITE_OK;
}

/*
** This function is called when a new transaction is opened, just after
** the first journal-header is written to the journal file.
*/
static int openTransaction(jt_file *pMain, jt_file *pJournal){
  unsigned char *aData;
  sqlite3_file *p = pMain->pReal;
  int rc = SQLITE_OK;

  closeTransaction(pMain);
  aData = sqlite3_malloc(pMain->nPagesize);
  pMain->pWritable = sqlite3BitvecCreate(pMain->nPage);
  pMain->aCksum = sqlite3_malloc(sizeof(u32) * (pMain->nPage + 1));
  pJournal->iMaxOff = 0;

  if( !pMain->pWritable || !pMain->aCksum || !aData ){
    rc = SQLITE_IOERR_NOMEM;
  }else if( pMain->nPage>0 ){
    u32 iTrunk;
    int iSave;
    int iSave2;

    stop_ioerr_simulation(&iSave, &iSave2);

    /* Read the database free-list. Add the page-number for each free-list
    ** leaf to the jt_file.pWritable bitvec.
    */
    rc = sqlite3OsRead(p, aData, pMain->nPagesize, 0);
    if( rc==SQLITE_OK ){
      u32 nDbsize = decodeUint32(&aData[28]);
      if( nDbsize>0 && memcmp(&aData[24], &aData[92], 4)==0 ){
        u32 iPg;
        for(iPg=nDbsize+1; iPg<=pMain->nPage; iPg++){
          sqlite3BitvecSet(pMain->pWritable, iPg);
        }
      }
    }
    iTrunk = decodeUint32(&aData[32]);
    while( rc==SQLITE_OK && iTrunk>0 ){
      u32 nLeaf;
      u32 iLeaf;
      sqlite3_int64 iOff = (iTrunk-1)*pMain->nPagesize;
      rc = sqlite3OsRead(p, aData, pMain->nPagesize, iOff);
      nLeaf = decodeUint32(&aData[4]);
      for(iLeaf=0; rc==SQLITE_OK && iLeaf<nLeaf; iLeaf++){
        u32 pgno = decodeUint32(&aData[8+4*iLeaf]);
        sqlite3BitvecSet(pMain->pWritable, pgno);
      }
      iTrunk = decodeUint32(aData);
    }

    /* Calculate and store a checksum for each page in the database file. */
    if( rc==SQLITE_OK ){
      int ii;
      for(ii=0; rc==SQLITE_OK && ii<pMain->nPage; ii++){
        i64 iOff = (i64)(pMain->nPagesize) * (i64)ii;
        if( iOff==PENDING_BYTE ) continue;
        rc = sqlite3OsRead(pMain->pReal, aData, pMain->nPagesize, iOff);
        pMain->aCksum[ii] = genCksum(aData, pMain->nPagesize);
      }
    }

    start_ioerr_simulation(iSave, iSave2);
  }

  sqlite3_free(aData);
  return rc;
}

/*
** The first argument to this function is a handle open on a journal file.
** This function reads the journal file and adds the page number for each
** page in the journal to the Bitvec object passed as the second argument.
*/
static int readJournalFile(jt_file *p, jt_file *pMain){
  int rc = SQLITE_OK;
  unsigned char zBuf[28];
  sqlite3_file *pReal = p->pReal;
  sqlite3_int64 iOff = 0;
  sqlite3_int64 iSize = p->iMaxOff;
  unsigned char *aPage;
  int iSave;
  int iSave2;

  aPage = sqlite3_malloc(pMain->nPagesize);
  if( !aPage ){
    return SQLITE_IOERR_NOMEM;
  }

  stop_ioerr_simulation(&iSave, &iSave2);

  while( rc==SQLITE_OK && iOff<iSize ){
    u32 nRec, nPage, nSector, nPagesize;
    u32 ii;

    /* Read and decode the next journal-header from the journal file. */
    rc = sqlite3OsRead(pReal, zBuf, 28, iOff);
    if( rc!=SQLITE_OK 
     || decodeJournalHdr(zBuf, &nRec, &nPage, &nSector, &nPagesize) 
    ){
      goto finish_rjf;
    }
    iOff += nSector;

    if( nRec==0 ){
      /* A trick. There might be another journal-header immediately 
      ** following this one. In this case, 0 records means 0 records, 
      ** not "read until the end of the file". See also ticket #2565.
      */
      if( iSize>=(iOff+nSector) ){
        rc = sqlite3OsRead(pReal, zBuf, 28, iOff);
        if( rc!=SQLITE_OK || 0==decodeJournalHdr(zBuf, 0, 0, 0, 0) ){
          continue;
        }
      }
      nRec = (iSize-iOff) / (pMain->nPagesize+8);
    }

    /* Read all the records that follow the journal-header just read. */
    for(ii=0; rc==SQLITE_OK && ii<nRec && iOff<iSize; ii++){
      u32 pgno;
      rc = sqlite3OsRead(pReal, zBuf, 4, iOff);
      if( rc==SQLITE_OK ){
        pgno = decodeUint32(zBuf);
        if( pgno>0 && pgno<=pMain->nPage ){
          if( 0==sqlite3BitvecTest(pMain->pWritable, pgno) ){
            rc = sqlite3OsRead(pReal, aPage, pMain->nPagesize, iOff+4);
            if( rc==SQLITE_OK ){
              u32 cksum = genCksum(aPage, pMain->nPagesize);
              assert( cksum==pMain->aCksum[pgno-1] );
            }
          }
          sqlite3BitvecSet(pMain->pWritable, pgno);
        }
        iOff += (8 + pMain->nPagesize);
      }
    }

    iOff = ((iOff + (nSector-1)) / nSector) * nSector;
  }

finish_rjf:
  start_ioerr_simulation(iSave, iSave2);
  sqlite3_free(aPage);
  if( rc==SQLITE_IOERR_SHORT_READ ){
    rc = SQLITE_OK;
  }
  return rc;
}

/*
** Write data to an jt-file.
*/
static int jtWrite(
  sqlite3_file *pFile, 
  const void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  int rc;
  jt_file *p = (jt_file *)pFile;
  if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){
    if( iOfst==0 ){
      jt_file *pMain = locateDatabaseHandle(p->zName);
      assert( pMain );
  
      if( iAmt==28 ){
        /* Zeroing the first journal-file header. This is the end of a
        ** transaction. */
        closeTransaction(pMain);
      }else if( iAmt!=12 ){
        /* Writing the first journal header to a journal file. This happens
        ** when a transaction is first started.  */
        u8 *z = (u8 *)zBuf;
        pMain->nPage = decodeUint32(&z[16]);
        pMain->nPagesize = decodeUint32(&z[24]);
        if( SQLITE_OK!=(rc=openTransaction(pMain, p)) ){
          return rc;
        }
      }
    }
    if( p->iMaxOff<(iOfst + iAmt) ){
      p->iMaxOff = iOfst + iAmt;
    }
  }

  if( p->flags&SQLITE_OPEN_MAIN_DB && p->pWritable ){
    if( iAmt<p->nPagesize 
     && p->nPagesize%iAmt==0 
     && iOfst>=(PENDING_BYTE+512) 
     && iOfst+iAmt<=PENDING_BYTE+p->nPagesize
    ){
      /* No-op. This special case is hit when the backup code is copying a
      ** to a database with a larger page-size than the source database and
      ** it needs to fill in the non-locking-region part of the original
      ** pending-byte page.
      */
    }else{
      u32 pgno = iOfst/p->nPagesize + 1;
      assert( (iAmt==1||iAmt==p->nPagesize) && ((iOfst+iAmt)%p->nPagesize)==0 );
      assert( pgno<=p->nPage || p->nSync>0 );
      assert( pgno>p->nPage || sqlite3BitvecTest(p->pWritable, pgno) );
    }
  }

  rc = sqlite3OsWrite(p->pReal, zBuf, iAmt, iOfst);
  if( (p->flags&SQLITE_OPEN_MAIN_JOURNAL) && iAmt==12 ){
    jt_file *pMain = locateDatabaseHandle(p->zName);
    int rc2 = readJournalFile(p, pMain);
    if( rc==SQLITE_OK ) rc = rc2;
  }
  return rc;
}

/*
** Truncate an jt-file.
*/
static int jtTruncate(sqlite3_file *pFile, sqlite_int64 size){
  jt_file *p = (jt_file *)pFile;
  if( p->flags&SQLITE_OPEN_MAIN_JOURNAL && size==0 ){
    /* Truncating a journal file. This is the end of a transaction. */
    jt_file *pMain = locateDatabaseHandle(p->zName);
    closeTransaction(pMain);
  }
  if( p->flags&SQLITE_OPEN_MAIN_DB && p->pWritable ){
    u32 pgno;
    u32 locking_page = (u32)(PENDING_BYTE/p->nPagesize+1);
    for(pgno=size/p->nPagesize+1; pgno<=p->nPage; pgno++){
      assert( pgno==locking_page || sqlite3BitvecTest(p->pWritable, pgno) );
    }
  }
  return sqlite3OsTruncate(p->pReal, size);
}

/*
** Sync an jt-file.
*/
static int jtSync(sqlite3_file *pFile, int flags){
  jt_file *p = (jt_file *)pFile;

  if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){
    int rc;
    jt_file *pMain;                   /* The associated database file */

    /* The journal file is being synced. At this point, we inspect the 
    ** contents of the file up to this point and set each bit in the 
    ** jt_file.pWritable bitvec of the main database file associated with
    ** this journal file.
    */
    pMain = locateDatabaseHandle(p->zName);
    assert(pMain);

    /* Set the bitvec values */
    if( pMain->pWritable ){
      pMain->nSync++;
      rc = readJournalFile(p, pMain);
      if( rc!=SQLITE_OK ){
        return rc;
      }
    }
  }

  return sqlite3OsSync(p->pReal, flags);
}

/*
** Return the current file-size of an jt-file.
*/
static int jtFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
  jt_file *p = (jt_file *)pFile;
  return sqlite3OsFileSize(p->pReal, pSize);
}

/*
** Lock an jt-file.
*/
static int jtLock(sqlite3_file *pFile, int eLock){
  int rc;
  jt_file *p = (jt_file *)pFile;
  rc = sqlite3OsLock(p->pReal, eLock);
  if( rc==SQLITE_OK && eLock>p->eLock ){
    p->eLock = eLock;
  }
  return rc;
}

/*
** Unlock an jt-file.
*/
static int jtUnlock(sqlite3_file *pFile, int eLock){
  int rc;
  jt_file *p = (jt_file *)pFile;
  rc = sqlite3OsUnlock(p->pReal, eLock);
  if( rc==SQLITE_OK && eLock<p->eLock ){
    p->eLock = eLock;
  }
  return rc;
}

/*
** Check if another file-handle holds a RESERVED lock on an jt-file.
*/
static int jtCheckReservedLock(sqlite3_file *pFile, int *pResOut){
  jt_file *p = (jt_file *)pFile;
  return sqlite3OsCheckReservedLock(p->pReal, pResOut);
}

/*
** File control method. For custom operations on an jt-file.
*/
static int jtFileControl(sqlite3_file *pFile, int op, void *pArg){
  jt_file *p = (jt_file *)pFile;
  return sqlite3OsFileControl(p->pReal, op, pArg);
}

/*
** Return the sector-size in bytes for an jt-file.
*/
static int jtSectorSize(sqlite3_file *pFile){
  jt_file *p = (jt_file *)pFile;
  return sqlite3OsSectorSize(p->pReal);
}

/*
** Return the device characteristic flags supported by an jt-file.
*/
static int jtDeviceCharacteristics(sqlite3_file *pFile){
  jt_file *p = (jt_file *)pFile;
  return sqlite3OsDeviceCharacteristics(p->pReal);
}

/*
** Open an jt file handle.
*/
static int jtOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_file *pFile,
  int flags,
  int *pOutFlags
){
  int rc;
  jt_file *p = (jt_file *)pFile;
  pFile->pMethods = 0;
  p->pReal = (sqlite3_file *)&p[1];
  p->pReal->pMethods = 0;
  rc = sqlite3OsOpen(g.pVfs, zName, p->pReal, flags, pOutFlags);
  assert( rc==SQLITE_OK || p->pReal->pMethods==0 );
  if( rc==SQLITE_OK ){
    pFile->pMethods = &jt_io_methods;
    p->eLock = 0;
    p->zName = zName;
    p->flags = flags;
    p->pNext = 0;
    p->pWritable = 0;
    p->aCksum = 0;
    enterJtMutex();
    if( zName ){
      p->pNext = g.pList;
      g.pList = p;
    }
    leaveJtMutex();
  }
  return rc;
}

/*
** Delete the file located at zPath. If the dirSync argument is true,
** ensure the file-system modifications are synced to disk before
** returning.
*/
static int jtDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  int nPath = strlen(zPath);
  if( nPath>8 && 0==strcmp("-journal", &zPath[nPath-8]) ){
    /* Deleting a journal file. The end of a transaction. */
    jt_file *pMain = locateDatabaseHandle(zPath);
    if( pMain ){
      closeTransaction(pMain);
    }
  }

  return sqlite3OsDelete(g.pVfs, zPath, dirSync);
}

/*
** Test for access permissions. Return true if the requested permission
** is available, or false otherwise.
*/
static int jtAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut
){
  return sqlite3OsAccess(g.pVfs, zPath, flags, pResOut);
}

/*
** 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 (JT_MAX_PATHNAME+1) bytes.
*/
static int jtFullPathname(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int nOut, 
  char *zOut
){
  return sqlite3OsFullPathname(g.pVfs, zPath, nOut, zOut);
}

/*
** Open the dynamic library located at zPath and return a handle.
*/
static void *jtDlOpen(sqlite3_vfs *pVfs, const char *zPath){
  return g.pVfs->xDlOpen(g.pVfs, zPath);
}

/*
** Populate the buffer zErrMsg (size nByte bytes) with a human readable
** utf-8 string describing the most recent error encountered associated 
** with dynamic libraries.
*/
static void jtDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
  g.pVfs->xDlError(g.pVfs, nByte, zErrMsg);
}

/*
** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
*/
static void (*jtDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
  return g.pVfs->xDlSym(g.pVfs, p, zSym);
}

/*
** Close the dynamic library handle pHandle.
*/
static void jtDlClose(sqlite3_vfs *pVfs, void *pHandle){
  g.pVfs->xDlClose(g.pVfs, pHandle);
}

/*
** Populate the buffer pointed to by zBufOut with nByte bytes of 
** random data.
*/
static int jtRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
  return sqlite3OsRandomness(g.pVfs, nByte, zBufOut);
}

/*
** Sleep for nMicro microseconds. Return the number of microseconds 
** actually slept.
*/
static int jtSleep(sqlite3_vfs *pVfs, int nMicro){
  return sqlite3OsSleep(g.pVfs, nMicro);
}

/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int jtCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
  return g.pVfs->xCurrentTime(g.pVfs, pTimeOut);
}
/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int jtCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
  return g.pVfs->xCurrentTimeInt64(g.pVfs, pTimeOut);
}

/**************************************************************************
** Start of public API.
*/

/*
** Configure the jt VFS as a wrapper around the VFS named by parameter 
** zWrap. If the isDefault parameter is true, then the jt VFS is installed
** as the new default VFS for SQLite connections. If isDefault is not
** true, then the jt VFS is installed as non-default. In this case it
** is available via its name, "jt".
*/
int jt_register(char *zWrap, int isDefault){
  g.pVfs = sqlite3_vfs_find(zWrap);
  if( g.pVfs==0 ){
    return SQLITE_ERROR;
  }
  jt_vfs.szOsFile = sizeof(jt_file) + g.pVfs->szOsFile;
  if( g.pVfs->iVersion==1 ){
    jt_vfs.iVersion = 1;
  }else if( g.pVfs->xCurrentTimeInt64==0 ){
    jt_vfs.xCurrentTimeInt64 = 0;
  }
  sqlite3_vfs_register(&jt_vfs, isDefault);
  return SQLITE_OK;
}

/*
** Uninstall the jt VFS, if it is installed.
*/
void jt_unregister(void){
  sqlite3_vfs_unregister(&jt_vfs);
}

#endif
/* [<][>][^][v][top][bottom][index][help] */
root/third_party/sqlite/src/src/test_journal.c

DEFINITIONS
