path: root/third_party/nix/src/libstore/pathlocks.hh

#pragma once

#include "util.hh"

namespace nix {

/* Open (possibly create) a lock file and return the file descriptor.
   -1 is returned if create is false and the lock could not be opened
   because it doesn't exist.  Any other error throws an exception. */
AutoCloseFD openLockFile(const Path& path, bool create);

/* Delete an open lock file. */
void deleteLockFile(const Path& path, int fd);

enum LockType { ltRead, ltWrite, ltNone };

bool lockFile(int fd, LockType lockType, bool wait);

class PathLocks {
 private:
  typedef std::pair<int, Path> FDPair;
  list<FDPair> fds;
  bool deletePaths;

 public:
  PathLocks();
  PathLocks(const PathSet& paths, const string& waitMsg = "");
  bool lockPaths(const PathSet& _paths, const string& waitMsg = "",
                 bool wait = true);
  ~PathLocks();
  void unlock();
  void setDeletion(bool deletePaths);
};

}  // namespace nix