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
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
#pragma once
///@file
#include "error.hh"
#include "file-descriptor.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;
std::list<FDPair> fds;
bool deletePaths;
public:
PathLocks();
PathLocks(const PathSet & paths,
const std::string & waitMsg = "");
bool lockPaths(const PathSet & _paths,
const std::string & waitMsg = "",
bool wait = true);
~PathLocks();
void unlock();
void setDeletion(bool deletePaths);
};
struct FdLock
{
int fd;
bool acquired = false;
FdLock(int fd, LockType lockType, bool wait, std::string_view waitMsg);
~FdLock()
{
try {
if (acquired)
lockFile(fd, ltNone, false);
} catch (SysError &) {
ignoreExceptionInDestructor();
}
}
};
}
|
