platform_bionic/libc/bionic/pthread_accessor.h

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef PTHREAD_ACCESSOR_H
#define PTHREAD_ACCESSOR_H

#include <pthread.h>

#include "pthread_internal.h"

class pthread_accessor {
 public:
  explicit pthread_accessor(pthread_t desired_thread) {
    Lock();
    for (thread_ = gThreadList; thread_ != NULL; thread_ = thread_->next) {
      if (thread_ == reinterpret_cast<pthread_internal_t*>(desired_thread)) {
        break;
      }
    }
  }

  ~pthread_accessor() {
    Unlock();
  }

  void Unlock() {
    if (is_locked_) {
      is_locked_ = false;
      thread_ = NULL;
      pthread_mutex_unlock(&gThreadListLock);
    }
  }

  pthread_internal_t& operator*() const { return *thread_; }
  pthread_internal_t* operator->() const { return thread_; }
  pthread_internal_t* get() const { return thread_; }

 private:
  pthread_internal_t* thread_;
  bool is_locked_;

  void Lock() {
    pthread_mutex_lock(&gThreadListLock);
    is_locked_ = true;
  }

  // Disallow copy and assignment.
  pthread_accessor(const pthread_accessor&);
  void operator=(const pthread_accessor&);
};

#endif // PTHREAD_ACCESSOR_H