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#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;
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);
}
};
}
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