Function VfsRdOnlyOpen

cvmfs/sqlitevfs.cc:218–274

* Supports only read-only opens. The "file name" has to be in the form of * '@ ', where file descriptor is usable by the cache manager. */

 * '@<file descriptor>', where file descriptor is usable by the cache manager.
 */
static int VfsRdOnlyOpen(sqlite3_vfs *vfs,
                         const char *zName,
                         sqlite3_file *pFile,
                         int flags,
                         int *pOutFlags) {
  static const sqlite3_io_methods io_methods = {1,  // iVersion
                                                VfsRdOnlyClose,
                                                VfsRdOnlyRead,
                                                VfsRdOnlyWrite,
                                                VfsRdOnlyTruncate,
                                                VfsRdOnlySync,
                                                VfsRdOnlyFileSize,
                                                VfsRdOnlyLock,
                                                VfsRdOnlyUnlock,
                                                VfsRdOnlyCheckReservedLock,
                                                VfsRdOnlyFileControl,
                                                VfsRdOnlySectorSize,
                                                VfsRdOnlyDeviceCharacteristics};

  VfsRdOnlyFile *p = reinterpret_cast<VfsRdOnlyFile *>(pFile);
  CacheManager *cache_mgr = reinterpret_cast<VfsRdOnly *>(vfs->pAppData)
                                ->cache_mgr;
  // Prevent xClose from being called in case of errors
  p->base.pMethods = NULL;

  if (flags & SQLITE_OPEN_READWRITE)
    return SQLITE_IOERR;
  if (flags & SQLITE_OPEN_DELETEONCLOSE)
    return SQLITE_IOERR;
  if (flags & SQLITE_OPEN_EXCLUSIVE)
    return SQLITE_IOERR;

  assert(zName && (zName[0] == '@'));
  p->fd = String2Int64(string(&zName[1]));
  if (p->fd < 0)
    return SQLITE_IOERR;
  const int64_t size = cache_mgr->GetSize(p->fd);
  if (size < 0) {
    cache_mgr->Close(p->fd);
    p->fd = -1;
    return SQLITE_IOERR_FSTAT;
  }
  if (cache_mgr->Readahead(p->fd) != 0) {
    cache_mgr->Close(p->fd);
    p->fd = -1;
    return SQLITE_IOERR;
  }
  p->size = static_cast<uint64_t>(size);
  if (pOutFlags)
    *pOutFlags = flags;
  p->vfs_rdonly = reinterpret_cast<VfsRdOnly *>(vfs->pAppData);
  p->base.pMethods = &io_methods;
  perf::Inc(p->vfs_rdonly->no_open);
  LogCvmfs(kLogSql, kLogDebug, "open sqlite3 catalog on fd %d, size %" PRIu64,
           p->fd, p->size);
  return SQLITE_OK;
}