VRShMem.h - mozsearch

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/* -*- 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 GFX_VR_VRSHMEM_H

#define GFX_VR_VRSHMEM_H

// This file declares VRShMem, which is used for cross-platform, cross-process

// communication between VR components.

// A shared memory handle is opened for the struct of type VRExternalShmem, and

// different processes write or read members of it to share data. Note that no

// process should be reading or writing to the same members, except for the

// versioning members used for synchronization.

#include "moz_external_vr.h"

#include "base/process.h"  // for base::ProcessHandle

#include <functional>

namespace mozilla {

namespace gfx {

class VRShMem final {

 public:

  VRShMem(volatile VRExternalShmem* aShmem, bool aRequiresMutex);

  ~VRShMem() = default;

  void CreateShMem(bool aCreateOnSharedMemory);

  void CreateShMemForAndroid();

  void ClearShMem();

  void CloseShMem();

  bool JoinShMem();

  void LeaveShMem();

  void PushBrowserState(VRBrowserState& aBrowserState, bool aNotifyCond);

  void PullBrowserState(mozilla::gfx::VRBrowserState& aState);

  void PushSystemState(const mozilla::gfx::VRSystemState& aState);

  void PullSystemState(

      VRDisplayState& aDisplayState, VRHMDSensorState& aSensorState,

      VRControllerState (&aControllerState)[kVRControllerMaxCount],

      bool& aEnumerationCompleted,

      const std::function<bool()>& aWaitCondition = nullptr);

  void PushWindowState(VRWindowState& aState);

  void PullWindowState(VRWindowState& aState);

  void PushTelemetryState(VRTelemetryState& aState);

  void PullTelemetryState(VRTelemetryState& aState);

  void SendIMEState(uint64_t aWindowID, mozilla::gfx::VRFxEventState aImeState);

  void SendFullscreenState(uint64_t aWindowID, bool aFullscreen);

  void SendShutdowmState(uint64_t aWindowID);

  bool HasExternalShmem() const { return mExternalShmem != nullptr; }

  bool IsSharedExternalShmem() const { return mIsSharedExternalShmem; }

  volatile VRExternalShmem* GetExternalShmem() const;

  bool IsDisplayStateShutdown() const;

 private:

  bool IsCreatedOnSharedMemory() const;

  void SendEvent(uint64_t aWindowID, mozilla::gfx::VRFxEventType aEventType,

                 mozilla::gfx::VRFxEventState aEventState);

  // mExternalShmem can have one of three sources:

  // - Allocated outside of this class on the heap and passed in via

  //   constructor, or acquired via GeckoVRManager (for GeckoView scenario).

  //   This is usually for scenarios where there is no VR process for cross-

  //   proc communication, and VRService is receiving the object.

  //   --> mIsSharedExternalShmem == true, IsCreatedOnSharedMemory() == false

  //   --> [Windows 7, Mac, Android, Linux]

  // - Allocated inside this class on the heap. This is usually for scenarios

  //   where there is no VR process, and VRManager is creating the object.

  //   --> mIsSharedExternalShmem == false, IsCreatedOnSharedMemory() == false

  //   --> [Windows 7, Mac, Linux]

  // - Allocated inside this class on shared memory. This is usually for

  //   scenarios where there is a VR process and cross-process communication

  //   is necessary

  //   --> mIsSharedExternalShmem == false, IsCreatedOnSharedMemory() == true

  //   --> [Windows 10 with VR process enabled]

  volatile VRExternalShmem* mExternalShmem = nullptr;

  // This member is true when mExternalShmem was allocated externally, via

  // being passed into the constructor or accessed via GeckoVRManager

  bool mIsSharedExternalShmem;

#if defined(XP_WIN)

  bool mRequiresMutex;

#endif

#if defined(XP_MACOSX)

  int mShmemFD;

#elif defined(XP_WIN)

  base::ProcessHandle mShmemFile;

  base::ProcessHandle mMutex;

#endif

#if !defined(MOZ_WIDGET_ANDROID)

  int64_t mBrowserGeneration = 0;

#endif

};

}  // namespace gfx

}  // namespace mozilla

#endif