Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 740 insertions, 0 deletions

diff --git a/gfx/vr/VRShMem.cpp b/gfx/vr/VRShMem.cpp
new file mode 100644
index 0000000000..b7d071cb88
--- /dev/null
+++ b/gfx/vr/VRShMem.cpp
@@ -0,0 +1,740 @@
+/* -*- 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/. */
+
+#include "VRShMem.h"
+
+#ifdef MOZILLA_INTERNAL_API
+#  include "nsString.h"
+#  include "nsXULAppAPI.h"
+#endif
+
+#include "gfxVRMutex.h"
+
+#if defined(XP_MACOSX)
+#  include <sys/mman.h>
+#  include <sys/stat.h> /* For mode constants */
+#  include <fcntl.h>    /* For O_* constants */
+#elif defined(MOZ_WIDGET_ANDROID)
+#  include "GeckoVRManager.h"
+#endif
+
+#if !defined(XP_WIN)
+#  include <unistd.h>  // for ::sleep
+#endif
+
+using namespace mozilla::gfx;
+
+#ifdef XP_WIN
+static const char* kShmemName = "moz.gecko.vr_ext." SHMEM_VERSION;
+static LPCTSTR kMutexName = TEXT("mozilla::vr::ShmemMutex" SHMEM_VERSION);
+#elif defined(XP_MACOSX)
+static const char* kShmemName = "/moz.gecko.vr_ext." SHMEM_VERSION;
+#endif  //  XP_WIN
+
+#if !defined(MOZ_WIDGET_ANDROID)
+namespace {
+void YieldThread() {
+#  if defined(XP_WIN)
+  ::Sleep(0);
+#  else
+  ::sleep(0);
+#  endif
+}
+}  // anonymous namespace
+#endif  // !defined(MOZ_WIDGET_ANDROID)
+
+VRShMem::VRShMem(volatile VRExternalShmem* aShmem, bool aRequiresMutex)
+    : mExternalShmem(aShmem),
+      mIsSharedExternalShmem(aShmem != nullptr)
+#if defined(XP_WIN)
+      ,
+      mRequiresMutex(aRequiresMutex)
+#endif
+#if defined(XP_MACOSX)
+      ,
+      mShmemFD(0)
+#elif defined(XP_WIN)
+      ,
+      mShmemFile(nullptr),
+      mMutex(nullptr)
+#endif
+{
+  // Regarding input parameters,
+  // - aShmem is null for VRManager or for VRService in multi-proc
+  // - aShmem is !null for VRService in-proc (i.e., no VR proc)
+}
+
+// Note: This function should only be called for in-proc scenarios, where the
+// shared memory is only shared within the same proc (rather than across
+// processes). Also, this local heap memory's lifetime is tied to the class.
+// Callers to this must ensure that its reference doesn't outlive the owning
+// VRShMem instance.
+volatile VRExternalShmem* VRShMem::GetExternalShmem() const {
+#if defined(XP_MACOSX)
+  MOZ_ASSERT(mShmemFD == 0);
+#elif defined(XP_WIN)
+  MOZ_ASSERT(mShmemFile == nullptr);
+#endif
+  return mExternalShmem;
+}
+
+bool VRShMem::IsDisplayStateShutdown() const {
+  // adapted from VRService::Refresh
+  // Does this need the mutex for getting .shutdown?
+  return mExternalShmem != nullptr &&
+         mExternalShmem->state.displayState.shutdown;
+}
+
+// This method returns true when there is a Shmem struct allocated and
+// when there is a shmem handle from the OS. This implies that the struct
+// is mapped to shared memory rather than being allocated on the heap by
+// this process.
+bool VRShMem::IsCreatedOnSharedMemory() const {
+#if defined(XP_MACOSX)
+  return HasExternalShmem() && (mShmemFD != 0);
+#elif defined(XP_WIN)
+  return HasExternalShmem() && (mShmemFile != nullptr);
+#else
+  // VRShMem does not support system shared memory on remaining platformss
+  return false;
+#endif
+}
+
+// CreateShMem allocates system shared memory for mExternalShmem and
+// synchronization primitives to protect it.
+// Callers/Processes to CreateShMem should followup with CloseShMem
+void VRShMem::CreateShMem(bool aCreateOnSharedMemory) {
+  if (HasExternalShmem()) {
+    MOZ_ASSERT(mIsSharedExternalShmem && !IsCreatedOnSharedMemory());
+    return;
+  }
+#if defined(XP_WIN)
+  if (mMutex == nullptr) {
+    mMutex = CreateMutex(nullptr,      // default security descriptor
+                         false,        // mutex not owned
+                         kMutexName);  // object name
+    if (mMutex == nullptr) {
+#  ifdef MOZILLA_INTERNAL_API
+      nsAutoCString msg;
+      msg.AppendPrintf("VRManager CreateMutex error \"%lu\".", GetLastError());
+      NS_WARNING(msg.get());
+#  endif
+      MOZ_ASSERT(false);
+      return;
+    }
+    // At xpcshell extension tests, it creates multiple VRManager
+    // instances in plug-contrainer.exe. It causes GetLastError() return
+    // `ERROR_ALREADY_EXISTS`. However, even though `ERROR_ALREADY_EXISTS`, it
+    // still returns the same mutex handle.
+    //
+    // https://docs.microsoft.com/en-us/windows/desktop/api/synchapi/nf-synchapi-createmutexa
+    MOZ_ASSERT(GetLastError() == 0 || GetLastError() == ERROR_ALREADY_EXISTS);
+  }
+#endif  // XP_WIN
+#if !defined(MOZ_WIDGET_ANDROID)
+  // The VR Service accesses all hardware from a separate process
+  // and replaces the other VRManager when enabled.
+  // If the VR process is not enabled, create an in-process VRService.
+  if (!aCreateOnSharedMemory) {
+    MOZ_ASSERT(mExternalShmem == nullptr);
+    // If the VR process is disabled, attempt to create a
+    // VR service within the current process on the heap
+    mExternalShmem = new VRExternalShmem();
+    ClearShMem();
+    return;
+  }
+#endif
+
+  MOZ_ASSERT(aCreateOnSharedMemory);
+
+#if defined(XP_MACOSX)
+  if (mShmemFD == 0) {
+    mShmemFD =
+        shm_open(kShmemName, O_RDWR, S_IRUSR | S_IWUSR | S_IROTH | S_IWOTH);
+  }
+  if (mShmemFD <= 0) {
+    mShmemFD = 0;
+    return;
+  }
+
+  struct stat sb;
+  fstat(mShmemFD, &sb);
+  off_t length = sb.st_size;
+  if (length < (off_t)sizeof(VRExternalShmem)) {
+    // TODO - Implement logging (Bug 1558912)
+    CloseShMem();
+    return;
+  }
+
+  mExternalShmem = (VRExternalShmem*)mmap(NULL, length, PROT_READ | PROT_WRITE,
+                                          MAP_SHARED, mShmemFD, 0);
+  if (mExternalShmem == MAP_FAILED) {
+    // TODO - Implement logging (Bug 1558912)
+    mExternalShmem = NULL;
+    CloseShMem();
+    return;
+  }
+
+#elif defined(XP_WIN)
+  if (mShmemFile == nullptr) {
+    mShmemFile =
+        CreateFileMappingA(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE, 0,
+                           sizeof(VRExternalShmem), kShmemName);
+    MOZ_ASSERT(GetLastError() == 0 || GetLastError() == ERROR_ALREADY_EXISTS);
+    MOZ_ASSERT(mShmemFile);
+    if (mShmemFile == nullptr) {
+      // TODO - Implement logging (Bug 1558912)
+      CloseShMem();
+      return;
+    }
+  }
+
+  LARGE_INTEGER length;
+  length.QuadPart = sizeof(VRExternalShmem);
+  mExternalShmem = (VRExternalShmem*)MapViewOfFile(
+      mShmemFile,           // handle to map object
+      FILE_MAP_ALL_ACCESS,  // read/write permission
+      0, 0, length.QuadPart);
+
+  if (mExternalShmem == nullptr) {
+    // TODO - Implement logging (Bug 1558912)
+    CloseShMem();
+    return;
+  }
+#elif defined(MOZ_WIDGET_ANDROID)
+  MOZ_ASSERT(false,
+             "CreateShMem should not be called for Android. Use "
+             "CreateShMemForAndroid instead");
+#endif
+}
+
+// This function sets mExternalShmem in the Android/GeckoView
+// scenarios where the host creates it in-memory and VRShMem
+// accesses it via GeckVRManager.
+void VRShMem::CreateShMemForAndroid() {
+#if defined(MOZ_WIDGET_ANDROID) && defined(MOZILLA_INTERNAL_API)
+  mExternalShmem =
+      (VRExternalShmem*)mozilla::GeckoVRManager::GetExternalContext();
+  if (!mExternalShmem) {
+    return;
+  } else {
+    mIsSharedExternalShmem = true;
+  }
+
+  int32_t version = -1;
+  int32_t size = 0;
+  if (pthread_mutex_lock((pthread_mutex_t*)&(mExternalShmem->systemMutex)) ==
+      0) {
+    version = mExternalShmem->version;
+    size = mExternalShmem->size;
+    pthread_mutex_unlock((pthread_mutex_t*)&(mExternalShmem->systemMutex));
+  } else {
+    return;
+  }
+  if (version != kVRExternalVersion) {
+    mExternalShmem = nullptr;
+    return;
+  }
+  if (size != sizeof(VRExternalShmem)) {
+    mExternalShmem = nullptr;
+    return;
+  }
+#endif
+}
+
+void VRShMem::ClearShMem() {
+  if (mExternalShmem != nullptr) {
+#ifdef MOZILLA_INTERNAL_API
+    // VRExternalShmem is asserted to be POD
+    mExternalShmem->Clear();
+#else
+    memset((void*)mExternalShmem, 0, sizeof(VRExternalShmem));
+#endif
+  }
+}
+
+// The cleanup corresponding to CreateShMem
+void VRShMem::CloseShMem() {
+#if !defined(MOZ_WIDGET_ANDROID)
+  if (!IsCreatedOnSharedMemory()) {
+    MOZ_ASSERT(!mIsSharedExternalShmem);
+    if (mExternalShmem) {
+      delete mExternalShmem;
+      mExternalShmem = nullptr;
+    }
+    return;
+  }
+#endif
+#if defined(XP_MACOSX)
+  if (mExternalShmem) {
+    munmap((void*)mExternalShmem, sizeof(VRExternalShmem));
+    mExternalShmem = NULL;
+  }
+  if (mShmemFD) {
+    close(mShmemFD);
+    mShmemFD = 0;
+  }
+#elif defined(XP_WIN)
+  if (mExternalShmem) {
+    UnmapViewOfFile((void*)mExternalShmem);
+    mExternalShmem = nullptr;
+  }
+  if (mShmemFile) {
+    CloseHandle(mShmemFile);
+    mShmemFile = nullptr;
+  }
+#elif defined(MOZ_WIDGET_ANDROID)
+  mExternalShmem = NULL;
+#endif
+
+#if defined(XP_WIN)
+  if (mMutex) {
+    MOZ_ASSERT(mRequiresMutex);
+    CloseHandle(mMutex);
+    mMutex = nullptr;
+  }
+#endif
+}
+
+// Called to use an existing shmem instance created by another process
+// Callers to JoinShMem should call LeaveShMem for cleanup
+bool VRShMem::JoinShMem() {
+#if defined(XP_WIN)
+  if (!mMutex && mRequiresMutex) {
+    // Check that there are no errors before making system calls
+    MOZ_ASSERT(GetLastError() == 0);
+
+    mMutex = OpenMutex(MUTEX_ALL_ACCESS,  // request full access
+                       false,             // handle not inheritable
+                       kMutexName);       // object name
+
+    if (mMutex == nullptr) {
+#  ifdef MOZILLA_INTERNAL_API
+      nsAutoCString msg;
+      msg.AppendPrintf("VRService OpenMutex error \"%lu\".", GetLastError());
+      NS_WARNING(msg.get());
+#  endif
+      return false;
+    }
+    MOZ_ASSERT(GetLastError() == 0);
+  }
+#endif
+
+  if (HasExternalShmem()) {
+    // An ExternalShmem is already set. No need to override and rejoin
+    return true;
+  }
+
+#if defined(XP_WIN)
+  // Opening a file-mapping object by name
+  base::ProcessHandle targetHandle =
+      OpenFileMappingA(FILE_MAP_ALL_ACCESS,  // read/write access
+                       FALSE,                // do not inherit the name
+                       kShmemName);          // name of mapping object
+
+  MOZ_ASSERT(GetLastError() == 0);
+
+  LARGE_INTEGER length;
+  length.QuadPart = sizeof(VRExternalShmem);
+  mExternalShmem = (VRExternalShmem*)MapViewOfFile(
+      reinterpret_cast<base::ProcessHandle>(
+          targetHandle),    // handle to map object
+      FILE_MAP_ALL_ACCESS,  // read/write permission
+      0, 0, length.QuadPart);
+  MOZ_ASSERT(GetLastError() == 0);
+
+  // TODO - Implement logging (Bug 1558912)
+  mShmemFile = targetHandle;
+  if (!mExternalShmem) {
+    MOZ_ASSERT(mExternalShmem);
+    return false;
+  }
+#else
+  // TODO: Implement shmem for other platforms.
+  //
+  // TODO: ** Does this mean that ShMem only works in Windows for now? If so,
+  // let's delete the code from other platforms (Bug 1563234)
+  MOZ_ASSERT(false, "JoinShMem not implemented");
+#endif
+  return true;
+}
+
+// The cleanup corresponding to JoinShMem
+void VRShMem::LeaveShMem() {
+#if defined(XP_WIN)
+  // Check that there are no errors before making system calls
+  MOZ_ASSERT(GetLastError() == 0);
+
+  if (mShmemFile) {
+    ::CloseHandle(mShmemFile);
+    mShmemFile = nullptr;
+  }
+#endif
+
+  if (mExternalShmem != nullptr) {
+#if defined(XP_WIN)
+    if (IsCreatedOnSharedMemory()) {
+      UnmapViewOfFile((void*)mExternalShmem);
+      MOZ_ASSERT(GetLastError() == 0);
+    }
+    // Otherwise, if not created on shared memory, simply null the shared
+    // reference to the heap object. The call to CloseShMem will appropriately
+    // free the allocation.
+#endif
+    mExternalShmem = nullptr;
+  }
+#if defined(XP_WIN)
+  if (mMutex) {
+    MOZ_ASSERT(mRequiresMutex);
+    CloseHandle(mMutex);
+    mMutex = nullptr;
+  }
+#endif
+}
+
+void VRShMem::PushBrowserState(VRBrowserState& aBrowserState,
+                               bool aNotifyCond) {
+  if (!mExternalShmem) {
+    return;
+  }
+#if defined(MOZ_WIDGET_ANDROID)
+  if (pthread_mutex_lock((pthread_mutex_t*)&(mExternalShmem->geckoMutex)) ==
+      0) {
+    memcpy((void*)&(mExternalShmem->geckoState), (void*)&aBrowserState,
+           sizeof(VRBrowserState));
+    if (aNotifyCond) {
+      pthread_cond_signal((pthread_cond_t*)&(mExternalShmem->geckoCond));
+    }
+    pthread_mutex_unlock((pthread_mutex_t*)&(mExternalShmem->geckoMutex));
+  }
+#else
+  bool status = true;
+
+#  if defined(XP_WIN)
+  WaitForMutex lock(mMutex);
+  status = lock.GetStatus();
+#  endif  // defined(XP_WIN)
+
+  if (status) {
+    mExternalShmem->geckoGenerationA = mExternalShmem->geckoGenerationA + 1;
+    memcpy((void*)&(mExternalShmem->geckoState), (void*)&aBrowserState,
+           sizeof(VRBrowserState));
+    mExternalShmem->geckoGenerationB = mExternalShmem->geckoGenerationB + 1;
+  }
+#endif    // defined(MOZ_WIDGET_ANDROID)
+}
+
+void VRShMem::PullBrowserState(mozilla::gfx::VRBrowserState& aState) {
+  if (!mExternalShmem) {
+    return;
+  }
+  // Copying the browser state from the shmem is non-blocking
+  // on x86/x64 architectures.  Arm requires a mutex that is
+  // locked for the duration of the memcpy to and from shmem on
+  // both sides.
+  // On x86/x64 It is fallable -- If a dirty copy is detected by
+  // a mismatch of geckoGenerationA and geckoGenerationB,
+  // the copy is discarded and will not replace the last known
+  // browser state.
+
+#if defined(MOZ_WIDGET_ANDROID)
+  // TODO: This code is out-of-date and fails to compile, as
+  // VRService isn't compiled for Android (Bug 1563234)
+  /*
+  if (pthread_mutex_lock((pthread_mutex_t*)&(mExternalShmem->geckoMutex)) ==
+      0) {
+    memcpy(&aState, &tmp.geckoState, sizeof(VRBrowserState));
+    pthread_mutex_unlock((pthread_mutex_t*)&(mExternalShmem->geckoMutex));
+  }
+  */
+  MOZ_ASSERT(false, "PullBrowserState not implemented");
+#else
+  bool status = true;
+#  if defined(XP_WIN)
+  if (mRequiresMutex) {
+    // TODO: Is this scoped lock okay? Seems like it should allow some
+    // race condition (Bug 1563234)
+    WaitForMutex lock(mMutex);
+    status = lock.GetStatus();
+  }
+#  endif  // defined(XP_WIN)
+  if (status) {
+    VRExternalShmem tmp;
+    if (mExternalShmem->geckoGenerationA != mBrowserGeneration) {
+      // TODO - (void *) cast removes volatile semantics.
+      // The memcpy is not likely to be optimized out, but is theoretically
+      // possible.  Suggest refactoring to either explicitly enforce memory
+      // order or to use locks.
+      memcpy(&tmp, (void*)mExternalShmem, sizeof(VRExternalShmem));
+      if (tmp.geckoGenerationA == tmp.geckoGenerationB &&
+          tmp.geckoGenerationA != 0) {
+        memcpy(&aState, &tmp.geckoState, sizeof(VRBrowserState));
+        mBrowserGeneration = tmp.geckoGenerationA;
+      }
+    }
+  }
+#endif    // defined(MOZ_WIDGET_ANDROID)
+}
+
+void VRShMem::PushSystemState(const mozilla::gfx::VRSystemState& aState) {
+  if (!mExternalShmem) {
+    return;
+  }
+  // Copying the VR service state to the shmem is atomic, infallable,
+  // and non-blocking on x86/x64 architectures.  Arm requires a mutex
+  // that is locked for the duration of the memcpy to and from shmem on
+  // both sides.
+
+#if defined(MOZ_WIDGET_ANDROID)
+  // TODO: This code is out-of-date and fails to compile, as
+  // VRService isn't compiled for Android (Bug 1563234)
+  MOZ_ASSERT(false, "JoinShMem not implemented");
+  /*
+  if (pthread_mutex_lock((pthread_mutex_t*)&(mExternalShmem->systemMutex)) ==
+      0) {
+    // We are casting away the volatile keyword, which is not accepted by
+    // memcpy.  It is possible (although very unlikely) that the compiler
+    // may optimize out the memcpy here as memcpy isn't explicitly safe for
+    // volatile memory in the C++ standard.
+    memcpy((void*)&mExternalShmem->state, &aState, sizeof(VRSystemState));
+    pthread_mutex_unlock((pthread_mutex_t*)&(mExternalShmem->systemMutex));
+  }
+  */
+#else
+  bool lockState = true;
+
+#  if defined(XP_WIN)
+  if (mRequiresMutex) {
+    // TODO: Is this scoped lock okay? Seems like it should allow some
+    // race condition (Bug 1563234)
+    WaitForMutex lock(mMutex);
+    lockState = lock.GetStatus();
+  }
+#  endif  // defined(XP_WIN)
+
+  if (lockState) {
+    mExternalShmem->generationA = mExternalShmem->generationA + 1;
+    memcpy((void*)&mExternalShmem->state, &aState, sizeof(VRSystemState));
+    mExternalShmem->generationB = mExternalShmem->generationB + 1;
+  }
+#endif    // defined(MOZ_WIDGET_ANDROID)
+}
+
+#if defined(MOZ_WIDGET_ANDROID)
+void VRShMem::PullSystemState(
+    VRDisplayState& aDisplayState, VRHMDSensorState& aSensorState,
+    VRControllerState (&aControllerState)[kVRControllerMaxCount],
+    bool& aEnumerationCompleted,
+    const std::function<bool()>& aWaitCondition /* = nullptr */) {
+  if (!mExternalShmem) {
+    return;
+  }
+  bool done = false;
+  while (!done) {
+    if (pthread_mutex_lock((pthread_mutex_t*)&(mExternalShmem->systemMutex)) ==
+        0) {
+      while (true) {
+        memcpy(&aDisplayState, (void*)&(mExternalShmem->state.displayState),
+               sizeof(VRDisplayState));
+        memcpy(&aSensorState, (void*)&(mExternalShmem->state.sensorState),
+               sizeof(VRHMDSensorState));
+        memcpy(aControllerState,
+               (void*)&(mExternalShmem->state.controllerState),
+               sizeof(VRControllerState) * kVRControllerMaxCount);
+        aEnumerationCompleted = mExternalShmem->state.enumerationCompleted;
+        if (!aWaitCondition || aWaitCondition()) {
+          done = true;
+          break;
+        }
+        // Block current thead using the condition variable until data
+        // changes
+        pthread_cond_wait((pthread_cond_t*)&mExternalShmem->systemCond,
+                          (pthread_mutex_t*)&mExternalShmem->systemMutex);
+      }  // while (true)
+      pthread_mutex_unlock((pthread_mutex_t*)&(mExternalShmem->systemMutex));
+    } else if (!aWaitCondition) {
+      // pthread_mutex_lock failed and we are not waiting for a condition to
+      // exit from PullState call.
+      return;
+    }
+  }  // while (!done) {
+}
+#else
+void VRShMem::PullSystemState(
+    VRDisplayState& aDisplayState, VRHMDSensorState& aSensorState,
+    VRControllerState (&aControllerState)[kVRControllerMaxCount],
+    bool& aEnumerationCompleted,
+    const std::function<bool()>& aWaitCondition /* = nullptr */) {
+  MOZ_ASSERT(mExternalShmem);
+  if (!mExternalShmem) {
+    return;
+  }
+  while (true) {
+    {  // Scope for WaitForMutex
+#  if defined(XP_WIN)
+      bool status = true;
+      WaitForMutex lock(mMutex);
+      status = lock.GetStatus();
+      if (status) {
+#  endif  // defined(XP_WIN)
+        VRExternalShmem tmp;
+        memcpy(&tmp, (void*)mExternalShmem, sizeof(VRExternalShmem));
+        bool isCleanCopy =
+            tmp.generationA == tmp.generationB && tmp.generationA != 0;
+        if (isCleanCopy) {
+          memcpy(&aDisplayState, &tmp.state.displayState,
+                 sizeof(VRDisplayState));
+          memcpy(&aSensorState, &tmp.state.sensorState,
+                 sizeof(VRHMDSensorState));
+          memcpy(aControllerState,
+                 (void*)&(mExternalShmem->state.controllerState),
+                 sizeof(VRControllerState) * kVRControllerMaxCount);
+          aEnumerationCompleted = mExternalShmem->state.enumerationCompleted;
+          // Check for wait condition
+          if (!aWaitCondition || aWaitCondition()) {
+            return;
+          }
+        } else if (!aWaitCondition) {
+          // We did not get a clean copy, and we are not waiting for a condition
+          // to exit from PullState call.
+          return;
+        }
+        // Yield the thread while polling
+        YieldThread();
+#  if defined(XP_WIN)
+      } else if (!aWaitCondition) {
+        // WaitForMutex failed and we are not waiting for a condition to
+        // exit from PullState call.
+        return;
+      }
+#  endif  // defined(XP_WIN)
+    }  // End: Scope for WaitForMutex
+    // Yield the thread while polling
+    YieldThread();
+  }  // while (!true)
+}
+#endif    // defined(MOZ_WIDGET_ANDROID)
+
+void VRShMem::PushWindowState(VRWindowState& aState) {
+#if defined(XP_WIN)
+  if (!mExternalShmem) {
+    return;
+  }
+
+  bool status = true;
+  WaitForMutex lock(mMutex);
+  status = lock.GetStatus();
+  if (status) {
+    memcpy((void*)&(mExternalShmem->windowState), (void*)&aState,
+           sizeof(VRWindowState));
+  }
+#endif  // defined(XP_WIN)
+}
+
+void VRShMem::PullWindowState(VRWindowState& aState) {
+#if defined(XP_WIN)
+  if (!mExternalShmem) {
+    return;
+  }
+
+  bool status = true;
+  WaitForMutex lock(mMutex);
+  status = lock.GetStatus();
+  if (status) {
+    memcpy((void*)&aState, (void*)&(mExternalShmem->windowState),
+           sizeof(VRWindowState));
+  }
+#endif  // defined(XP_WIN)
+}
+
+void VRShMem::PushTelemetryState(VRTelemetryState& aState) {
+#if defined(XP_WIN)
+  if (!mExternalShmem) {
+    return;
+  }
+
+  bool status = true;
+  WaitForMutex lock(mMutex);
+  status = lock.GetStatus();
+  if (status) {
+    memcpy((void*)&(mExternalShmem->telemetryState), (void*)&aState,
+           sizeof(VRTelemetryState));
+  }
+#endif  // defined(XP_WIN)
+}
+void VRShMem::PullTelemetryState(VRTelemetryState& aState) {
+#if defined(XP_WIN)
+  if (!mExternalShmem) {
+    return;
+  }
+
+  bool status = true;
+  WaitForMutex lock(mMutex);
+  status = lock.GetStatus();
+  if (status) {
+    memcpy((void*)&aState, (void*)&(mExternalShmem->telemetryState),
+           sizeof(VRTelemetryState));
+  }
+#endif  // defined(XP_WIN)
+}
+
+void VRShMem::SendEvent(uint64_t aWindowID,
+                        mozilla::gfx::VRFxEventType aEventType,
+                        mozilla::gfx::VRFxEventState aEventState) {
+  MOZ_ASSERT(!HasExternalShmem());
+  if (JoinShMem()) {
+    mozilla::gfx::VRWindowState windowState = {0};
+    PullWindowState(windowState);
+    windowState.windowID = aWindowID;
+    windowState.eventType = aEventType;
+    windowState.eventState = aEventState;
+    PushWindowState(windowState);
+    LeaveShMem();
+
+#if defined(XP_WIN)
+    // Notify the waiting host process that the data is now available
+    HANDLE hSignal = ::OpenEventA(EVENT_ALL_ACCESS,       // dwDesiredAccess
+                                  FALSE,                  // bInheritHandle
+                                  windowState.signalName  // lpName
+    );
+    ::SetEvent(hSignal);
+    ::CloseHandle(hSignal);
+#endif  // defined(XP_WIN)
+  }
+}
+
+void VRShMem::SendIMEState(uint64_t aWindowID,
+                           mozilla::gfx::VRFxEventState aEventState) {
+  SendEvent(aWindowID, mozilla::gfx::VRFxEventType::IME, aEventState);
+}
+
+void VRShMem::SendFullscreenState(uint64_t aWindowID, bool aFullscreen) {
+  SendEvent(aWindowID, mozilla::gfx::VRFxEventType::FULLSCREEN,
+            aFullscreen ? mozilla::gfx::VRFxEventState::FULLSCREEN_ENTER
+                        : mozilla::gfx::VRFxEventState::FULLSCREEN_EXIT);
+}
+
+// Note: this should be called from the VRShMem instance that created
+// the external shmem rather than joined it.
+void VRShMem::SendShutdowmState(uint64_t aWindowID) {
+  MOZ_ASSERT(HasExternalShmem());
+
+  mozilla::gfx::VRWindowState windowState = {0};
+  PullWindowState(windowState);
+  windowState.windowID = aWindowID;
+  windowState.eventType = mozilla::gfx::VRFxEventType::SHUTDOWN;
+  PushWindowState(windowState);
+
+#if defined(XP_WIN)
+  // Notify the waiting host process that the data is now available
+  HANDLE hSignal = ::OpenEventA(EVENT_ALL_ACCESS,       // dwDesiredAccess
+                                FALSE,                  // bInheritHandle
+                                windowState.signalName  // lpName
+  );
+  ::SetEvent(hSignal);
+  ::CloseHandle(hSignal);
+#endif  // defined(XP_WIN)
+}