mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-24 03:33:20 +01:00
89 lines
2.8 KiB
C++
89 lines
2.8 KiB
C++
//===--- LockFileManager.h - File-level locking utility ---------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
#ifndef LLVM_SUPPORT_LOCKFILEMANAGER_H
|
|
#define LLVM_SUPPORT_LOCKFILEMANAGER_H
|
|
|
|
#include "llvm/ADT/Optional.h"
|
|
#include "llvm/ADT/SmallString.h"
|
|
#include "llvm/ADT/StringRef.h"
|
|
#include <system_error>
|
|
#include <utility> // for std::pair
|
|
|
|
namespace llvm {
|
|
/// \brief Class that manages the creation of a lock file to aid
|
|
/// implicit coordination between different processes.
|
|
///
|
|
/// The implicit coordination works by creating a ".lock" file alongside
|
|
/// the file that we're coordinating for, using the atomicity of the file
|
|
/// system to ensure that only a single process can create that ".lock" file.
|
|
/// When the lock file is removed, the owning process has finished the
|
|
/// operation.
|
|
class LockFileManager {
|
|
public:
|
|
/// \brief Describes the state of a lock file.
|
|
enum LockFileState {
|
|
/// \brief The lock file has been created and is owned by this instance
|
|
/// of the object.
|
|
LFS_Owned,
|
|
/// \brief The lock file already exists and is owned by some other
|
|
/// instance.
|
|
LFS_Shared,
|
|
/// \brief An error occurred while trying to create or find the lock
|
|
/// file.
|
|
LFS_Error
|
|
};
|
|
|
|
/// \brief Describes the result of waiting for the owner to release the lock.
|
|
enum WaitForUnlockResult {
|
|
/// \brief The lock was released successfully.
|
|
Res_Success,
|
|
/// \brief Owner died while holding the lock.
|
|
Res_OwnerDied,
|
|
/// \brief Reached timeout while waiting for the owner to release the lock.
|
|
Res_Timeout
|
|
};
|
|
|
|
private:
|
|
SmallString<128> FileName;
|
|
SmallString<128> LockFileName;
|
|
SmallString<128> UniqueLockFileName;
|
|
|
|
Optional<std::pair<std::string, int> > Owner;
|
|
Optional<std::error_code> Error;
|
|
|
|
LockFileManager(const LockFileManager &) = delete;
|
|
LockFileManager &operator=(const LockFileManager &) = delete;
|
|
|
|
static Optional<std::pair<std::string, int> >
|
|
readLockFile(StringRef LockFileName);
|
|
|
|
static bool processStillExecuting(StringRef Hostname, int PID);
|
|
|
|
public:
|
|
|
|
LockFileManager(StringRef FileName);
|
|
~LockFileManager();
|
|
|
|
/// \brief Determine the state of the lock file.
|
|
LockFileState getState() const;
|
|
|
|
operator LockFileState() const { return getState(); }
|
|
|
|
/// \brief For a shared lock, wait until the owner releases the lock.
|
|
WaitForUnlockResult waitForUnlock();
|
|
|
|
/// \brief Remove the lock file. This may delete a different lock file than
|
|
/// the one previously read if there is a race.
|
|
std::error_code unsafeRemoveLockFile();
|
|
};
|
|
|
|
} // end namespace llvm
|
|
|
|
#endif // LLVM_SUPPORT_LOCKFILEMANAGER_H
|