nix/libstore/pathlocks.hh

   1 #pragma once
   2
   3 #include "types.hh"
   4
   5
   6 namespace nix {
   7
   8
   9 /* Open (possibly create) a lock file and return the file descriptor.
  10    -1 is returned if create is false and the lock could not be opened
  11    because it doesn't exist.  Any other error throws an exception. */
  12 int openLockFile(const Path & path, bool create);
  13
  14 /* Delete an open lock file. */
  15 void deleteLockFile(const Path & path, int fd);
  16
  17 enum LockType { ltRead, ltWrite, ltNone };
  18
  19 bool lockFile(int fd, LockType lockType, bool wait);
  20
  21
  22 class PathLocks
  23 {
  24 private:
  25     typedef std::pair<int, Path> FDPair;
  26     list<FDPair> fds;
  27     bool deletePaths;
  28
  29 public:
  30     PathLocks();
  31     PathLocks(const PathSet & paths,
  32         const string & waitMsg = "");
  33     bool lockPaths(const PathSet & _paths,
  34         const string & waitMsg = "",
  35         bool wait = true);
  36     ~PathLocks();
  37     void unlock();
  38     void setDeletion(bool deletePaths);
  39 };
  40
  41
  42 bool pathIsLockedByMe(const Path & path);
  43
  44
  45 }