gecko-dev/ipc/glue/MessagePump.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 __IPC_GLUE_MESSAGEPUMP_H__
#define __IPC_GLUE_MESSAGEPUMP_H__

#include "base/message_pump_default.h"
#if defined(XP_WIN)
#  include "base/message_pump_win.h"
#endif

#include "base/time.h"
#include "mozilla/Attributes.h"
#include "mozilla/Mutex.h"
#include "nsCOMPtr.h"
#include "nsIThreadInternal.h"

class nsIEventTarget;
class nsITimer;

namespace mozilla {
namespace ipc {

class DoWorkRunnable;

class MessagePump : public base::MessagePumpDefault {
  friend class DoWorkRunnable;

 public:
  explicit MessagePump(nsIEventTarget* aEventTarget);

  // From base::MessagePump.
  virtual void Run(base::MessagePump::Delegate* aDelegate) override;

  // From base::MessagePump.
  virtual void ScheduleWork() override;

  // From base::MessagePump.
  virtual void ScheduleWorkForNestedLoop() override;

  // From base::MessagePump.
  virtual void ScheduleDelayedWork(
      const base::TimeTicks& aDelayedWorkTime) override;

  virtual nsIEventTarget* GetXPCOMThread() override;

 protected:
  virtual ~MessagePump();

 private:
  // Only called by DoWorkRunnable.
  void DoDelayedWork(base::MessagePump::Delegate* aDelegate);

 protected:
  nsIEventTarget* mEventTarget;

  // mDelayedWorkTimer and mEventTarget are set in Run() by this class or its
  // subclasses.
  nsCOMPtr<nsITimer> mDelayedWorkTimer;

 private:
  // Only accessed by this class.
  RefPtr<DoWorkRunnable> mDoWorkEvent;
};

class MessagePumpForChildProcess final : public MessagePump {
 public:
  MessagePumpForChildProcess() : MessagePump(nullptr), mFirstRun(true) {}

  virtual void Run(base::MessagePump::Delegate* aDelegate) override;

 private:
  ~MessagePumpForChildProcess() = default;

  bool mFirstRun;
};

class MessagePumpForNonMainThreads final : public MessagePump {
 public:
  explicit MessagePumpForNonMainThreads(nsIEventTarget* aEventTarget)
      : MessagePump(aEventTarget) {}

  virtual void Run(base::MessagePump::Delegate* aDelegate) override;

 private:
  ~MessagePumpForNonMainThreads() = default;
};

#if defined(XP_WIN)
// Extends the TYPE_UI message pump to process xpcom events. Currently only
// implemented for Win.
class MessagePumpForNonMainUIThreads final : public base::MessagePumpForUI,
                                             public nsIThreadObserver {
 public:
  // We don't want xpcom refing, chromium controls our lifetime via
  // RefCountedThreadSafe.
  NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override { return 2; }
  NS_IMETHOD_(MozExternalRefCountType) Release(void) override { return 1; }
  NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;

  NS_DECL_NSITHREADOBSERVER

 public:
  explicit MessagePumpForNonMainUIThreads(nsIEventTarget* aEventTarget)
      : mInWait(false), mWaitLock("mInWait") {}

  // The main run loop for this thread.
  virtual void DoRunLoop() override;

  virtual nsIEventTarget* GetXPCOMThread() override {
    return nullptr;  // not sure what to do with this one
  }

 protected:
  void SetInWait() {
    MutexAutoLock lock(mWaitLock);
    mInWait = true;
  }

  void ClearInWait() {
    MutexAutoLock lock(mWaitLock);
    mInWait = false;
  }

  bool GetInWait() {
    MutexAutoLock lock(mWaitLock);
    return mInWait;
  }

 private:
  ~MessagePumpForNonMainUIThreads() {}

  bool mInWait;
  mozilla::Mutex mWaitLock;
};
#endif  // defined(XP_WIN)

#if defined(MOZ_WIDGET_ANDROID)
/*`
 * The MessagePumpForAndroidUI exists to enable IPDL in the Android UI thread.
 * The Android UI thread event loop is controlled by Android. This prevents
 * running an existing MessagePump implementation in the Android UI thread. In
 * order to enable IPDL on the Android UI thread it is necessary to have a
 * non-looping MessagePump. This class enables forwarding of nsIRunnables from
 * MessageLoop::PostTask_Helper to the registered nsIEventTarget with out the
 * need to control the event loop. The only member function that should be
 * invoked is GetXPCOMThread. All other member functions will invoke MOZ_CRASH
 */
class MessagePumpForAndroidUI : public base::MessagePump {
 public:
  explicit MessagePumpForAndroidUI(nsIEventTarget* aEventTarget)
      : mEventTarget(aEventTarget) {}

  virtual void Run(Delegate* delegate);
  virtual void Quit();
  virtual void ScheduleWork();
  virtual void ScheduleDelayedWork(const base::TimeTicks& delayed_work_time);
  virtual nsIEventTarget* GetXPCOMThread() { return mEventTarget; }

 private:
  ~MessagePumpForAndroidUI() {}
  MessagePumpForAndroidUI() {}

  nsIEventTarget* mEventTarget;
};
#endif  // defined(MOZ_WIDGET_ANDROID)

} /* namespace ipc */
} /* namespace mozilla */

#endif /* __IPC_GLUE_MESSAGEPUMP_H__ */