mutex.cc

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// 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 "src/base/platform/platform.h"
 
namespace v8 {
namespace base {
 
RecursiveMutex::~RecursiveMutex() {
  DCHECK_EQ(0, level_);
}
 
void RecursiveMutex::Lock() {
  int own_id = v8::base::OS::GetCurrentThreadId();
  if (thread_id_ == own_id) {
    level_++;
    return;
  }
  mutex_.Lock();
  DCHECK_EQ(0, level_);
  thread_id_ = own_id;
  level_ = 1;
}
 
void RecursiveMutex::Unlock() {
#ifdef DEBUG
  int own_id = v8::base::OS::GetCurrentThreadId();
  CHECK_EQ(thread_id_, own_id);
#endif
  if ((--level_) == 0) {
    thread_id_ = 0;
    mutex_.Unlock();
  }
}
 
bool RecursiveMutex::TryLock() {
  int own_id = v8::base::OS::GetCurrentThreadId();
  if (thread_id_ == own_id) {
    level_++;
    return true;
  }
  if (mutex_.TryLock()) {
    DCHECK_EQ(0, level_);
    thread_id_ = own_id;
    level_ = 1;
    return true;
  }
  return false;
}
 
Mutex::Mutex() {
#ifdef DEBUG
  level_ = 0;
#endif
}
 
Mutex::~Mutex() { DCHECK_EQ(0, level_); }
 
void Mutex::Lock() ABSL_NO_THREAD_SAFETY_ANALYSIS {
  native_handle_.Lock();
  AssertUnheldAndMark();
}
 
void Mutex::Unlock() ABSL_NO_THREAD_SAFETY_ANALYSIS {
  AssertHeldAndUnmark();
  native_handle_.Unlock();
}
 
bool Mutex::TryLock() ABSL_NO_THREAD_SAFETY_ANALYSIS {
  if (!native_handle_.TryLock()) return false;
  AssertUnheldAndMark();
  return true;
}
 
}  // namespace base
}  // namespace v8