nix-super/src/libstore/pathlocks.hh
John Ericson 0746951be1
Finish converting existing comments for internal API docs (#8146)
* Finish converting existing comments for internal API docs

99% of this was just reformatting existing comments. Only two exceptions:

- Expanded upon `BuildResult::status` compat note

- Split up file-level `symbol-table.hh` doc comments to get
  per-definition docs

Also fixed a few whitespace goofs, turning leading tabs to spaces and
removing trailing spaces.

Picking up from #8133

* Fix two things from comments

* Use triple-backtick not indent for `dumpPath`

* Convert GNU-style `\`..'` quotes to markdown style in API docs

This will render correctly.
2023-04-07 13:55:28 +00:00

57 lines
1.1 KiB
C++

#pragma once
///@file
#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;
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()
{
if (acquired)
lockFile(fd, ltNone, false);
}
};
}