/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 */

#include <thrift/thrift-config.h>

#include <thrift/concurrency/Monitor.h>
#include <thrift/concurrency/Exception.h>
#include <thrift/concurrency/Util.h>
#include <thrift/transport/PlatformSocket.h>
#include <thrift/stdcxx.h>

#include <assert.h>

#include <iostream>

#include <pthread.h>

namespace apache {
namespace thrift {

using stdcxx::scoped_ptr;
using stdcxx::shared_ptr;

namespace concurrency {

/**
 * Monitor implementation using the POSIX pthread library
 *
 * @version $Id:$
 */
class Monitor::Impl {

public:
  Impl() : ownedMutex_(new Mutex()), mutex_(NULL), condInitialized_(false) {
    init(ownedMutex_.get());
  }

  Impl(Mutex* mutex) : mutex_(NULL), condInitialized_(false) { init(mutex); }

  Impl(Monitor* monitor) : mutex_(NULL), condInitialized_(false) { init(&(monitor->mutex())); }

  ~Impl() { cleanup(); }

  Mutex& mutex() { return *mutex_; }
  void lock() { mutex().lock(); }
  void unlock() { mutex().unlock(); }

  /**
   * Exception-throwing version of waitForTimeRelative(), called simply
   * wait(int64) for historical reasons.  Timeout is in milliseconds.
   *
   * If the condition occurs,  this function returns cleanly; on timeout or
   * error an exception is thrown.
   */
  void wait(int64_t timeout_ms) const {
    int result = waitForTimeRelative(timeout_ms);
    if (result == THRIFT_ETIMEDOUT) {
      // pthread_cond_timedwait has been observed to return early on
      // various platforms, so comment out this assert.
      // assert(Util::currentTime() >= (now + timeout));
      throw TimedOutException();
    } else if (result != 0) {
      throw TException("pthread_cond_wait() or pthread_cond_timedwait() failed");
    }
  }

  /**
   * Waits until the specified timeout in milliseconds for the condition to
   * occur, or waits forever if timeout_ms == 0.
   *
   * Returns 0 if condition occurs, THRIFT_ETIMEDOUT on timeout, or an error code.
   */
  int waitForTimeRelative(int64_t timeout_ms) const {
    if (timeout_ms == 0LL) {
      return waitForever();
    }

    struct THRIFT_TIMESPEC abstime;
    Util::toTimespec(abstime, Util::currentTime() + timeout_ms);
    return waitForTime(&abstime);
  }

  /**
   * Waits until the absolute time specified using struct THRIFT_TIMESPEC.
   * Returns 0 if condition occurs, THRIFT_ETIMEDOUT on timeout, or an error code.
   */
  int waitForTime(const THRIFT_TIMESPEC* abstime) const {
    assert(mutex_);
    pthread_mutex_t* mutexImpl = reinterpret_cast<pthread_mutex_t*>(mutex_->getUnderlyingImpl());
    assert(mutexImpl);

    // XXX Need to assert that caller owns mutex
    return pthread_cond_timedwait(&pthread_cond_, mutexImpl, abstime);
  }

  int waitForTime(const struct timeval* abstime) const {
    struct THRIFT_TIMESPEC temp;
    temp.tv_sec = abstime->tv_sec;
    temp.tv_nsec = abstime->tv_usec * 1000;
    return waitForTime(&temp);
  }
  /**
   * Waits forever until the condition occurs.
   * Returns 0 if condition occurs, or an error code otherwise.
   */
  int waitForever() const {
    assert(mutex_);
    pthread_mutex_t* mutexImpl = reinterpret_cast<pthread_mutex_t*>(mutex_->getUnderlyingImpl());
    assert(mutexImpl);
    return pthread_cond_wait(&pthread_cond_, mutexImpl);
  }

  void notify() {
    // XXX Need to assert that caller owns mutex
    int iret = pthread_cond_signal(&pthread_cond_);
    THRIFT_UNUSED_VARIABLE(iret);
    assert(iret == 0);
  }

  void notifyAll() {
    // XXX Need to assert that caller owns mutex
    int iret = pthread_cond_broadcast(&pthread_cond_);
    THRIFT_UNUSED_VARIABLE(iret);
    assert(iret == 0);
  }

private:
  void init(Mutex* mutex) {
    mutex_ = mutex;

    if (pthread_cond_init(&pthread_cond_, NULL) == 0) {
      condInitialized_ = true;
    }

    if (!condInitialized_) {
      cleanup();
      throw SystemResourceException();
    }
  }

  void cleanup() {
    if (condInitialized_) {
      condInitialized_ = false;
      int iret = pthread_cond_destroy(&pthread_cond_);
      THRIFT_UNUSED_VARIABLE(iret);
      assert(iret == 0);
    }
  }

  scoped_ptr<Mutex> ownedMutex_;
  Mutex* mutex_;

  mutable pthread_cond_t pthread_cond_;
  mutable bool condInitialized_;
};

Monitor::Monitor() : impl_(new Monitor::Impl()) {
}
Monitor::Monitor(Mutex* mutex) : impl_(new Monitor::Impl(mutex)) {
}
Monitor::Monitor(Monitor* monitor) : impl_(new Monitor::Impl(monitor)) {
}

Monitor::~Monitor() {
  delete impl_;
}

Mutex& Monitor::mutex() const {
  return impl_->mutex();
}

void Monitor::lock() const {
  impl_->lock();
}

void Monitor::unlock() const {
  impl_->unlock();
}

void Monitor::wait(int64_t timeout) const {
  impl_->wait(timeout);
}

int Monitor::waitForTime(const THRIFT_TIMESPEC* abstime) const {
  return impl_->waitForTime(abstime);
}

int Monitor::waitForTime(const timeval* abstime) const {
  return impl_->waitForTime(abstime);
}

int Monitor::waitForTimeRelative(int64_t timeout_ms) const {
  return impl_->waitForTimeRelative(timeout_ms);
}

int Monitor::waitForever() const {
  return impl_->waitForever();
}

void Monitor::notify() const {
  impl_->notify();
}

void Monitor::notifyAll() const {
  impl_->notifyAll();
}
}
}
} // apache::thrift::concurrency
