gecko-dev/gfx/2d/JobScheduler_posix.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef WIN32
#  ifndef MOZILLA_GFX_TASKSCHEDULER_POSIX_H_
#    define MOZILLA_GFX_TASKSCHEDULER_POSIX_H_

#    include <string>
#    include <vector>
#    include <list>
#    include <pthread.h>
#    include <stdint.h>
#    include <stdio.h>

#    include "mozilla/RefPtr.h"
#    include "mozilla/DebugOnly.h"
#    include "mozilla/gfx/CriticalSection.h"
#    include "mozilla/RefCounted.h"

namespace mozilla {
namespace gfx {

class Job;
class PosixCondVar;
class WorkerThread;

// posix platforms only!
class PosixCondVar {
 public:
  PosixCondVar() {
    DebugOnly<int> err = pthread_cond_init(&mCond, nullptr);
    MOZ_ASSERT(!err);
  }

  ~PosixCondVar() {
    DebugOnly<int> err = pthread_cond_destroy(&mCond);
    MOZ_ASSERT(!err);
  }

  void Wait(CriticalSection* aMutex) {
    DebugOnly<int> err = pthread_cond_wait(&mCond, &aMutex->mMutex);
    MOZ_ASSERT(!err);
  }

  void Broadcast() {
    DebugOnly<int> err = pthread_cond_broadcast(&mCond);
    MOZ_ASSERT(!err);
  }

 protected:
  pthread_cond_t mCond;
};

/// A simple and naive multithreaded task queue
///
/// The public interface of this class must remain identical to its equivalent
/// in JobScheduler_win32.h
class MultiThreadedJobQueue {
 public:
  enum AccessType { BLOCKING, NON_BLOCKING };

  // Producer thread
  MultiThreadedJobQueue();

  // Producer thread
  ~MultiThreadedJobQueue();

  // Worker threads
  bool WaitForJob(Job*& aOutJob);

  // Any thread
  bool PopJob(Job*& aOutJob, AccessType aAccess);

  // Any threads
  void SubmitJob(Job* aJob);

  // Producer thread
  void ShutDown();

  // Any thread
  size_t NumJobs();

  // Any thread
  bool IsEmpty();

  // Producer thread
  void RegisterThread();

  // Worker threads
  void UnregisterThread();

 protected:
  std::list<Job*> mJobs;
  CriticalSection mMutex;
  PosixCondVar mAvailableCondvar;
  PosixCondVar mShutdownCondvar;
  int32_t mThreadsCount;
  bool mShuttingDown;

  friend class WorkerThread;
};

/// An object that a thread can synchronously wait on.
/// Usually set by a SetEventJob.
class EventObject : public external::AtomicRefCounted<EventObject> {
 public:
  MOZ_DECLARE_REFCOUNTED_TYPENAME(EventObject)

  EventObject();

  ~EventObject();

  /// Synchronously wait until the event is set.
  void Wait();

  /// Return true if the event is set, without blocking.
  bool Peak();

  /// Set the event.
  void Set();

 protected:
  CriticalSection mMutex;
  PosixCondVar mCond;
  bool mIsSet;
};

}  // namespace gfx
}  // namespace mozilla

#    include "JobScheduler.h"

#  endif
#endif