lix/src/libstore/pathlocks.hh
Eelco Dolstra e349f2c0a3
Use BSD instead of POSIX file locks
POSIX file locks are essentially incompatible with multithreading. BSD
locks have much saner semantics. We need this now that there can be
multiple concurrent LocalStore::buildPaths() invocations.
2019-08-02 18:39:16 +02:00

39 lines
902 B
C++

#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);
};
}