src/libstore/pathlocks.hh


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46

#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);
};


// FIXME: not thread-safe!
bool pathIsLockedByMe(const Path & path);


}