llvm::LockFileManager Class Reference

Class that manages the creation of a lock file to aid implicit coordination between different processes. More...

#include "llvm/Support/LockFileManager.h"

Public Types
enum	LockFileState { LFS_Owned , LFS_Shared , LFS_Error }
	Describes the state of a lock file. More...
enum	WaitForUnlockResult { Res_Success , Res_OwnerDied , Res_Timeout }
	Describes the result of waiting for the owner to release the lock. More...

Public Member Functions
	LockFileManager (StringRef FileName)
	~LockFileManager ()
LockFileState	getState () const
	Determine the state of the lock file.
	operator LockFileState () const
WaitForUnlockResult	waitForUnlock (const unsigned MaxSeconds=90)
	For a shared lock, wait until the owner releases the lock.
std::error_code	unsafeRemoveLockFile ()
	Remove the lock file.
std::string	getErrorMessage () const
	Get error message, or "" if there is no error.
void	setError (const std::error_code &EC, StringRef ErrorMsg="")
	Set error and error message.

Detailed Description

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.

Definition at line 27 of file LockFileManager.h.

Member Enumeration Documentation

LockFileState

enum llvm::LockFileManager::LockFileState

Describes the state of a lock file.

Enumerator
LFS_Owned	The lock file has been created and is owned by this instance of the object.
LFS_Shared	The lock file already exists and is owned by some other instance.
LFS_Error	An error occurred while trying to create or find the lock file.

Definition at line 30 of file LockFileManager.h.

WaitForUnlockResult

enum llvm::LockFileManager::WaitForUnlockResult

Describes the result of waiting for the owner to release the lock.

Enumerator
Res_Success	The lock was released successfully.
Res_OwnerDied	Owner died while holding the lock.
Res_Timeout	Reached timeout while waiting for the owner to release the lock.

Definition at line 43 of file LockFileManager.h.

Constructor & Destructor Documentation

LockFileManager()

LockFileManager::LockFileManager

(

StringRef

FileName

)

Definition at line 160 of file LockFileManager.cpp.

References llvm::raw_fd_ostream::clear_error(), llvm::raw_fd_ostream::close(), llvm::sys::fs::create_link(), llvm::sys::fs::createUniqueFile(), llvm::raw_fd_ostream::error(), llvm::sys::fs::exists(), llvm::file_exists, getHostID(), llvm::sys::Process::getProcessId(), llvm::raw_fd_ostream::has_error(), llvm::sys::fs::make_absolute(), llvm::sys::fs::remove(), setError(), and llvm::SmallString< InternalLen >::str().

~LockFileManager()

LockFileManager::~LockFileManager

(

)

Definition at line 282 of file LockFileManager.cpp.

References llvm::sys::DontRemoveFileOnSignal(), getState(), LFS_Owned, and llvm::sys::fs::remove().

Member Function Documentation

getErrorMessage()

std::string LockFileManager::getErrorMessage

(

)

const

Get error message, or "" if there is no error.

Definition at line 270 of file LockFileManager.cpp.

getState()

LockFileManager::LockFileState LockFileManager::getState

(

)

const

Determine the state of the lock file.

Definition at line 260 of file LockFileManager.cpp.

References LFS_Error, LFS_Owned, and LFS_Shared.

Referenced by operator LockFileState(), waitForUnlock(), and ~LockFileManager().

operator LockFileState()

llvm::LockFileManager::operator LockFileState ( ) const

inline

Definition at line 77 of file LockFileManager.h.

References getState().

setError()

void llvm::LockFileManager::setError ( const std::error_code &  EC, StringRef  ErrorMsg = ""  )

inline

Set error and error message.

Definition at line 92 of file LockFileManager.h.

Referenced by LockFileManager().

unsafeRemoveLockFile()

std::error_code LockFileManager::unsafeRemoveLockFile

(

)

Remove the lock file.

This may delete a different lock file than the one previously read if there is a race.

Definition at line 326 of file LockFileManager.cpp.

References llvm::sys::fs::remove().

Referenced by llvm::AMDGPUSplitModulePass::run().

waitForUnlock()

LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock

(

const unsigned

MaxSeconds = 90

)

For a shared lock, wait until the owner releases the lock.

Total timeout for the file to appear is ~1.5 minutes.

Parameters

MaxSeconds

the maximum total wait time in seconds.

Definition at line 295 of file LockFileManager.cpp.

References llvm::sys::fs::access(), llvm::SmallString< InternalLen >::c_str(), llvm::sys::fs::Exist, llvm::sys::fs::exists(), getState(), LFS_Shared, llvm::no_such_file_or_directory, Res_OwnerDied, Res_Success, Res_Timeout, and llvm::ExponentialBackoff::waitForNextAttempt().

Referenced by llvm::AMDGPUSplitModulePass::run().

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The documentation for this class was generated from the following files:

• include/llvm/Support/LockFileManager.h
• lib/Support/LockFileManager.cpp