include/wvatomicfile.h

   1 /* -*- Mode: C++ -*-
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 1997-2005 Net Integration Technologies, Inc.
   4  *
   5  * A simple class to access filesystem files using WvStreams.
   6  */
   7 #ifndef __WVATOMFILE_H
   8 #define __WVATOMFILE_H
   9
  10 #include "wvfile.h"
  11
  12 /**
  13  * WvAtomicFile implements a simple extension to wvfile to allow for
  14  * atomic file creation.  Files normally can be created and written
  15  * to, however, in the event of a kernel panic the file can be left in
  16  * an unusable state.
  17  *
  18  * A WvAtomicFile is atomically created on file close
  19  *
  20  */
  21 class WvAtomicFile : public WvFile
  22 {
  23 private:
  24     WvString atomic_file;
  25     WvString tmp_file;
  26
  27 public:
  28     WvAtomicFile(WvStringParm filename, int flags = O_TRUNC | O_CREAT,
  29                     mode_t create_mode = 0666);
  30     ~WvAtomicFile();
  31
  32     bool open(WvStringParm filename, int flags = O_TRUNC | O_CREAT,
  33                 mode_t create_mode = 0666);
  34     void close();
  35
  36     // Like chmod(2), does *not* respect umask
  37     bool chmod(mode_t mode);
  38
  39     bool chown(uid_t owner, gid_t group);
  40
  41 public:
  42     const char *wstype() const { return "WvAtomicFile"; }
  43 };
  44
  45 #endif // __WVATOMFILE_H