chromium/v8/src/base/platform/mutex.cc

// Copyright 2013 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/base/platform/mutex.h"

#include <errno.h>

#include <atomic>

#include "src/base/platform/condition-variable.h"

#if DEBUG
#include <unordered_set>
#endif  // DEBUG

#if V8_OS_WIN
#include <windows.h>
#endif

namespace v8 {
namespace base {

#if DEBUG
namespace {
// Used for asserts to guarantee we are not re-locking a mutex on the same
// thread. If this thread has only one held shared mutex (common case), we use
// {single_held_shared_mutex}. If it has more than one we allocate a set for it.
// Said set has to manually be constructed and destroyed.
thread_local base::SharedMutex* single_held_shared_mutex = …;
TSet;
thread_local TSet* held_shared_mutexes = …;

// Returns true iff {shared_mutex} is not a held mutex.
bool SharedMutexNotHeld(SharedMutex* shared_mutex) { … }

// Tries to hold {shared_mutex}. Returns true iff it hadn't been held prior to
// this function call.
bool TryHoldSharedMutex(SharedMutex* shared_mutex) { … }

// Tries to release {shared_mutex}. Returns true iff it had been held prior to
// this function call.
bool TryReleaseSharedMutex(SharedMutex* shared_mutex) { … }
}  // namespace
#endif  // DEBUG

#if V8_OS_POSIX

static V8_INLINE void InitializeNativeHandle(pthread_mutex_t* mutex) { … }


static V8_INLINE void InitializeRecursiveNativeHandle(pthread_mutex_t* mutex) { … }


static V8_INLINE void DestroyNativeHandle(pthread_mutex_t* mutex) { … }


static V8_INLINE void LockNativeHandle(pthread_mutex_t* mutex) { … }


static V8_INLINE void UnlockNativeHandle(pthread_mutex_t* mutex) { … }


static V8_INLINE bool TryLockNativeHandle(pthread_mutex_t* mutex) { … }


Mutex::Mutex() { … }


Mutex::~Mutex() { … }


void Mutex::Lock() { … }


void Mutex::Unlock() { … }


bool Mutex::TryLock() { … }


RecursiveMutex::RecursiveMutex() { … }


RecursiveMutex::~RecursiveMutex() { … }


void RecursiveMutex::Lock() { … }


void RecursiveMutex::Unlock() { … }


bool RecursiveMutex::TryLock() { … }

#if V8_OS_DARWIN

SharedMutex::SharedMutex() = default;
SharedMutex::~SharedMutex() = default;

void SharedMutex::LockShared() {
  DCHECK(TryHoldSharedMutex(this));
  native_handle_.lock_shared();
}

void SharedMutex::LockExclusive() {
  DCHECK(TryHoldSharedMutex(this));
  native_handle_.lock();
}

void SharedMutex::UnlockShared() {
  DCHECK(TryReleaseSharedMutex(this));
  native_handle_.unlock_shared();
}

void SharedMutex::UnlockExclusive() {
  DCHECK(TryReleaseSharedMutex(this));
  native_handle_.unlock();
}

bool SharedMutex::TryLockShared() {
  DCHECK(SharedMutexNotHeld(this));
  bool result = native_handle_.try_lock_shared();
  if (result) DCHECK(TryHoldSharedMutex(this));
  return result;
}

bool SharedMutex::TryLockExclusive() {
  DCHECK(SharedMutexNotHeld(this));
  bool result = native_handle_.try_lock();
  if (result) DCHECK(TryHoldSharedMutex(this));
  return result;
}

#else  // !V8_OS_DARWIN

SharedMutex::SharedMutex() { … }

SharedMutex::~SharedMutex() { … }

void SharedMutex::LockShared() { … }

void SharedMutex::LockExclusive() { … }

void SharedMutex::UnlockShared() { … }

void SharedMutex::UnlockExclusive() { … }

bool SharedMutex::TryLockShared() { … }

bool SharedMutex::TryLockExclusive() { … }

#endif  // !V8_OS_DARWIN

#elif V8_OS_WIN

Mutex::Mutex() : native_handle_(SRWLOCK_INIT) {
#ifdef DEBUG
  level_ = 0;
#endif
}


Mutex::~Mutex() {
  DCHECK_EQ(0, level_);
}


void Mutex::Lock() {
  AcquireSRWLockExclusive(V8ToWindowsType(&native_handle_));
  AssertUnheldAndMark();
}


void Mutex::Unlock() {
  AssertHeldAndUnmark();
  ReleaseSRWLockExclusive(V8ToWindowsType(&native_handle_));
}


bool Mutex::TryLock() {
  if (!TryAcquireSRWLockExclusive(V8ToWindowsType(&native_handle_))) {
    return false;
  }
  AssertUnheldAndMark();
  return true;
}


RecursiveMutex::RecursiveMutex() {
  InitializeCriticalSection(V8ToWindowsType(&native_handle_));
#ifdef DEBUG
  level_ = 0;
#endif
}


RecursiveMutex::~RecursiveMutex() {
  DeleteCriticalSection(V8ToWindowsType(&native_handle_));
  DCHECK_EQ(0, level_);
}


void RecursiveMutex::Lock() {
  EnterCriticalSection(V8ToWindowsType(&native_handle_));
#ifdef DEBUG
  DCHECK_LE(0, level_);
  level_++;
#endif
}


void RecursiveMutex::Unlock() {
#ifdef DEBUG
  DCHECK_LT(0, level_);
  level_--;
#endif
  LeaveCriticalSection(V8ToWindowsType(&native_handle_));
}


bool RecursiveMutex::TryLock() {
  if (!TryEnterCriticalSection(V8ToWindowsType(&native_handle_))) {
    return false;
  }
#ifdef DEBUG
  DCHECK_LE(0, level_);
  level_++;
#endif
  return true;
}

SharedMutex::SharedMutex() : native_handle_(SRWLOCK_INIT) {}

SharedMutex::~SharedMutex() {}

void SharedMutex::LockShared() {
  DCHECK(TryHoldSharedMutex(this));
  AcquireSRWLockShared(V8ToWindowsType(&native_handle_));
}

void SharedMutex::LockExclusive() {
  DCHECK(TryHoldSharedMutex(this));
  AcquireSRWLockExclusive(V8ToWindowsType(&native_handle_));
}

void SharedMutex::UnlockShared() {
  DCHECK(TryReleaseSharedMutex(this));
  ReleaseSRWLockShared(V8ToWindowsType(&native_handle_));
}

void SharedMutex::UnlockExclusive() {
  DCHECK(TryReleaseSharedMutex(this));
  ReleaseSRWLockExclusive(V8ToWindowsType(&native_handle_));
}

bool SharedMutex::TryLockShared() {
  DCHECK(SharedMutexNotHeld(this));
  bool result = TryAcquireSRWLockShared(V8ToWindowsType(&native_handle_));
  if (result) DCHECK(TryHoldSharedMutex(this));
  return result;
}

bool SharedMutex::TryLockExclusive() {
  DCHECK(SharedMutexNotHeld(this));
  bool result = TryAcquireSRWLockExclusive(V8ToWindowsType(&native_handle_));
  if (result) DCHECK(TryHoldSharedMutex(this));
  return result;
}

#elif V8_OS_STARBOARD

Mutex::Mutex() { SbMutexCreate(&native_handle_); }

Mutex::~Mutex() { SbMutexDestroy(&native_handle_); }

void Mutex::Lock() { SbMutexAcquire(&native_handle_); }

void Mutex::Unlock() { SbMutexRelease(&native_handle_); }

RecursiveMutex::RecursiveMutex() {}

RecursiveMutex::~RecursiveMutex() {}

void RecursiveMutex::Lock() { native_handle_.Acquire(); }

void RecursiveMutex::Unlock() { native_handle_.Release(); }

bool RecursiveMutex::TryLock() { return native_handle_.AcquireTry(); }

SharedMutex::SharedMutex() = default;

SharedMutex::~SharedMutex() = default;

void SharedMutex::LockShared() {
  DCHECK(TryHoldSharedMutex(this));
  native_handle_.AcquireReadLock();
}

void SharedMutex::LockExclusive() {
  DCHECK(TryHoldSharedMutex(this));
  native_handle_.AcquireWriteLock();
}

void SharedMutex::UnlockShared() {
  DCHECK(TryReleaseSharedMutex(this));
  native_handle_.ReleaseReadLock();
}

void SharedMutex::UnlockExclusive() {
  DCHECK(TryReleaseSharedMutex(this));
  native_handle_.ReleaseWriteLock();
}

bool SharedMutex::TryLockShared() {
  DCHECK(SharedMutexNotHeld(this));
  return false;
}

bool SharedMutex::TryLockExclusive() {
  DCHECK(SharedMutexNotHeld(this));
  return false;
}
#endif  // V8_OS_STARBOARD

}  // namespace base
}  // namespace v8