1 files changed, 418 insertions, 0 deletions
diff --git a/gfx/vr/service/VRService.cpp b/gfx/vr/service/VRService.cpp
new file mode 100644
index 0000000000..2b774c2531
--- /dev/null
+++ b/gfx/vr/service/VRService.cpp
@@ -0,0 +1,418 @@
+/* -*- 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 "VRService.h"
+
+#include <cstring>  // for memcmp
+
+#include "../VRShMem.h"
+#include "../gfxVRMutex.h"
+#include "PuppetSession.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "nsThread.h"
+#include "nsXULAppAPI.h"
+
+#if defined(XP_WIN)
+#  include "OculusSession.h"
+#endif
+
+#if defined(XP_WIN) || defined(XP_MACOSX) || \
+    (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
+#  include "OpenVRSession.h"
+#endif
+#if !defined(MOZ_WIDGET_ANDROID)
+#  include "OSVRSession.h"
+#endif
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+namespace {
+
+int64_t FrameIDFromBrowserState(const mozilla::gfx::VRBrowserState& aState) {
+  for (const auto& layer : aState.layerState) {
+    if (layer.type == VRLayerType::LayerType_Stereo_Immersive) {
+      return layer.layer_stereo_immersive.frameId;
+    }
+  }
+  return 0;
+}
+
+bool IsImmersiveContentActive(const mozilla::gfx::VRBrowserState& aState) {
+  for (const auto& layer : aState.layerState) {
+    if (layer.type == VRLayerType::LayerType_Stereo_Immersive) {
+      return true;
+    }
+  }
+  return false;
+}
+
+}  // anonymous namespace
+
+/*static*/
+already_AddRefed<VRService> VRService::Create(
+    volatile VRExternalShmem* aShmem) {
+  RefPtr<VRService> service = new VRService(aShmem);
+  return service.forget();
+}
+
+VRService::VRService(volatile VRExternalShmem* aShmem)
+    : mSystemState{},
+      mBrowserState{},
+      mShutdownRequested(false),
+      mLastHapticState{},
+      mFrameStartTime{} {
+  // When we have the VR process, we map the memory
+  // of mAPIShmem from GPU process and pass it to the CTOR.
+  // If we don't have the VR process, we will instantiate
+  // mAPIShmem in VRService.
+  mShmem = new VRShMem(aShmem, aShmem == nullptr /*aRequiresMutex*/);
+}
+
+VRService::~VRService() {
+  // PSA: We must store the value of any staticPrefs preferences as this
+  // destructor will be called after staticPrefs has been shut down.
+  StopInternal(true /*aFromDtor*/);
+}
+
+void VRService::Refresh() {
+  if (mShmem != nullptr && mShmem->IsDisplayStateShutdown()) {
+    Stop();
+  }
+}
+
+void VRService::Start() {
+  if (!mServiceThread) {
+    /**
+     * We must ensure that any time the service is re-started, that
+     * the VRSystemState is reset, including mSystemState.enumerationCompleted
+     * This must happen before VRService::Start returns to the caller, in order
+     * to prevent the WebVR/WebXR promises from being resolved before the
+     * enumeration has been completed.
+     */
+    memset(&mSystemState, 0, sizeof(mSystemState));
+    PushState(mSystemState);
+    RefPtr<VRService> self = this;
+    nsCOMPtr<nsIThread> thread;
+    nsresult rv = NS_NewNamedThread(
+        "VRService", getter_AddRefs(thread),
+        NS_NewRunnableFunction("VRService::ServiceThreadStartup", [self]() {
+          self->mBackgroundHangMonitor =
+              MakeUnique<mozilla::BackgroundHangMonitor>(
+                  "VRService",
+                  /* Timeout values are powers-of-two to enable us get better
+                     data. 128ms is chosen for transient hangs because 8Hz
+                     should be the minimally acceptable goal for Compositor
+                     responsiveness (normal goal is 60Hz). */
+                  128,
+                  /* 2048ms is chosen for permanent hangs because it's longer
+                   * than most Compositor hangs seen in the wild, but is short
+                   * enough to not miss getting native hang stacks. */
+                  2048);
+          static_cast<nsThread*>(NS_GetCurrentThread())
+              ->SetUseHangMonitor(true);
+        }));
+
+    if (NS_FAILED(rv)) {
+      return;
+    }
+    thread.swap(mServiceThread);
+    // ServiceInitialize needs mServiceThread to be set in order to be able to
+    // assert that it's running on the right thread as well as dispatching new
+    // tasks. It can't be run within the NS_NewRunnableFunction initial event.
+    MOZ_ALWAYS_SUCCEEDS(mServiceThread->Dispatch(
+        NewRunnableMethod("gfx::VRService::ServiceInitialize", this,
+                          &VRService::ServiceInitialize)));
+  }
+}
+
+void VRService::Stop() { StopInternal(false /*aFromDtor*/); }
+
+void VRService::StopInternal(bool aFromDtor) {
+  if (mServiceThread) {
+    // We must disable the background hang monitor before we can shutdown this
+    // thread. Dispatched a last task to do so. No task will be allowed to run
+    // on the service thread after this one.
+    mServiceThread->Dispatch(NS_NewRunnableFunction(
+        "VRService::StopInternal", [self = RefPtr<VRService>(this), this] {
+          static_cast<nsThread*>(NS_GetCurrentThread())
+              ->SetUseHangMonitor(false);
+          mBackgroundHangMonitor = nullptr;
+        }));
+    mShutdownRequested = true;
+    mServiceThread->Shutdown();
+    mServiceThread = nullptr;
+  }
+
+  if (mShmem != nullptr && (aFromDtor || !mShmem->IsSharedExternalShmem())) {
+    // Only leave the VRShMem and clean up the pointer when the struct
+    // was not passed in. Otherwise, VRService will no longer have a
+    // way to access that struct if VRService starts again.
+    mShmem->LeaveShMem();
+    delete mShmem;
+    mShmem = nullptr;
+  }
+
+  mSession = nullptr;
+}
+
+bool VRService::InitShmem() { return mShmem->JoinShMem(); }
+
+bool VRService::IsInServiceThread() {
+  return mServiceThread && mServiceThread->IsOnCurrentThread();
+}
+
+void VRService::ServiceInitialize() {
+  MOZ_ASSERT(IsInServiceThread());
+
+  if (!InitShmem()) {
+    return;
+  }
+
+  mShutdownRequested = false;
+  // Get initial state from the browser
+  PullState(mBrowserState);
+
+  // Try to start a VRSession
+  UniquePtr<VRSession> session;
+
+  if (StaticPrefs::dom_vr_puppet_enabled()) {
+    // When the VR Puppet is enabled, we don't want
+    // to enumerate any real devices
+    session = MakeUnique<PuppetSession>();
+    if (!session->Initialize(mSystemState, mBrowserState.detectRuntimesOnly)) {
+      session = nullptr;
+    }
+  } else {
+    // We try Oculus first to ensure we use Oculus
+    // devices trough the most native interface
+    // when possible.
+#if defined(XP_WIN)
+    // Try Oculus
+    if (!session) {
+      session = MakeUnique<OculusSession>();
+      if (!session->Initialize(mSystemState,
+                               mBrowserState.detectRuntimesOnly)) {
+        session = nullptr;
+      }
+    }
+#endif
+
+#if defined(XP_WIN) || defined(XP_MACOSX) || \
+    (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
+    // Try OpenVR
+    if (!session) {
+      session = MakeUnique<OpenVRSession>();
+      if (!session->Initialize(mSystemState,
+                               mBrowserState.detectRuntimesOnly)) {
+        session = nullptr;
+      }
+    }
+#endif
+#if !defined(MOZ_WIDGET_ANDROID)
+    // Try OSVR
+    if (!session) {
+      session = MakeUnique<OSVRSession>();
+      if (!session->Initialize(mSystemState,
+                               mBrowserState.detectRuntimesOnly)) {
+        session = nullptr;
+      }
+    }
+#endif
+
+  }  // if (staticPrefs:VRPuppetEnabled())
+
+  if (session) {
+    mSession = std::move(session);
+    // Setting enumerationCompleted to true indicates to the browser
+    // that it should resolve any promises in the WebVR/WebXR API
+    // waiting for hardware detection.
+    mSystemState.enumerationCompleted = true;
+    PushState(mSystemState);
+
+    mServiceThread->Dispatch(
+        NewRunnableMethod("gfx::VRService::ServiceWaitForImmersive", this,
+                          &VRService::ServiceWaitForImmersive));
+  } else {
+    // VR hardware was not detected.
+    // We must inform the browser of the failure so it may try again
+    // later and resolve WebVR promises.  A failure or shutdown is
+    // indicated by enumerationCompleted being set to true, with all
+    // other fields remaining zeroed out.
+    VRDisplayCapabilityFlags capFlags =
+        mSystemState.displayState.capabilityFlags;
+    memset(&mSystemState, 0, sizeof(mSystemState));
+    mSystemState.enumerationCompleted = true;
+
+    if (mBrowserState.detectRuntimesOnly) {
+      mSystemState.displayState.capabilityFlags = capFlags;
+    } else {
+      mSystemState.displayState.minRestartInterval =
+          StaticPrefs::dom_vr_external_notdetected_timeout();
+    }
+    mSystemState.displayState.shutdown = true;
+    PushState(mSystemState);
+  }
+}
+
+void VRService::ServiceShutdown() {
+  MOZ_ASSERT(IsInServiceThread());
+
+  // Notify the browser that we have shut down.
+  // This is indicated by enumerationCompleted being set
+  // to true, with all other fields remaining zeroed out.
+  memset(&mSystemState, 0, sizeof(mSystemState));
+  mSystemState.enumerationCompleted = true;
+  mSystemState.displayState.shutdown = true;
+  if (mSession && mSession->ShouldQuit()) {
+    mSystemState.displayState.minRestartInterval =
+        StaticPrefs::dom_vr_external_quit_timeout();
+  }
+  PushState(mSystemState);
+  mSession = nullptr;
+}
+
+void VRService::ServiceWaitForImmersive() {
+  MOZ_ASSERT(IsInServiceThread());
+  MOZ_ASSERT(mSession);
+
+  mSession->ProcessEvents(mSystemState);
+  PushState(mSystemState);
+  PullState(mBrowserState);
+
+  if (mSession->ShouldQuit() || mShutdownRequested) {
+    // Shut down
+    mServiceThread->Dispatch(NewRunnableMethod(
+        "gfx::VRService::ServiceShutdown", this, &VRService::ServiceShutdown));
+  } else if (IsImmersiveContentActive(mBrowserState)) {
+    // Enter Immersive Mode
+    mSession->StartPresentation();
+    mSession->StartFrame(mSystemState);
+    PushState(mSystemState);
+
+    mServiceThread->Dispatch(
+        NewRunnableMethod("gfx::VRService::ServiceImmersiveMode", this,
+                          &VRService::ServiceImmersiveMode));
+  } else {
+    // Continue waiting for immersive mode
+    mServiceThread->Dispatch(
+        NewRunnableMethod("gfx::VRService::ServiceWaitForImmersive", this,
+                          &VRService::ServiceWaitForImmersive));
+  }
+}
+
+void VRService::ServiceImmersiveMode() {
+  MOZ_ASSERT(IsInServiceThread());
+  MOZ_ASSERT(mSession);
+
+  mSession->ProcessEvents(mSystemState);
+  UpdateHaptics();
+  PushState(mSystemState);
+  PullState(mBrowserState);
+
+  if (mSession->ShouldQuit() || mShutdownRequested) {
+    // Shut down
+    mServiceThread->Dispatch(NewRunnableMethod(
+        "gfx::VRService::ServiceShutdown", this, &VRService::ServiceShutdown));
+    return;
+  }
+
+  if (!IsImmersiveContentActive(mBrowserState)) {
+    // Exit immersive mode
+    mSession->StopAllHaptics();
+    mSession->StopPresentation();
+    mServiceThread->Dispatch(
+        NewRunnableMethod("gfx::VRService::ServiceWaitForImmersive", this,
+                          &VRService::ServiceWaitForImmersive));
+    return;
+  }
+
+  uint64_t newFrameId = FrameIDFromBrowserState(mBrowserState);
+  if (newFrameId != mSystemState.displayState.lastSubmittedFrameId) {
+    // A new immersive frame has been received.
+    // Submit the textures to the VR system compositor.
+    bool success = false;
+    for (const auto& layer : mBrowserState.layerState) {
+      if (layer.type == VRLayerType::LayerType_Stereo_Immersive) {
+        // SubmitFrame may block in order to control the timing for
+        // the next frame start
+        success = mSession->SubmitFrame(layer.layer_stereo_immersive);
+        break;
+      }
+    }
+
+    // Changing mLastSubmittedFrameId triggers a new frame to start
+    // rendering.  Changes to mLastSubmittedFrameId and the values
+    // used for rendering, such as headset pose, must be pushed
+    // atomically to the browser.
+    mSystemState.displayState.lastSubmittedFrameId = newFrameId;
+    mSystemState.displayState.lastSubmittedFrameSuccessful = success;
+
+    // StartFrame may block to control the timing for the next frame start
+    mSession->StartFrame(mSystemState);
+    mSystemState.sensorState.inputFrameID++;
+    size_t historyIndex =
+        mSystemState.sensorState.inputFrameID % ArrayLength(mFrameStartTime);
+    mFrameStartTime[historyIndex] = TimeStamp::Now();
+    PushState(mSystemState);
+  }
+
+  // Continue immersive mode
+  mServiceThread->Dispatch(
+      NewRunnableMethod("gfx::VRService::ServiceImmersiveMode", this,
+                        &VRService::ServiceImmersiveMode));
+}
+
+void VRService::UpdateHaptics() {
+  MOZ_ASSERT(IsInServiceThread());
+  MOZ_ASSERT(mSession);
+
+  for (size_t i = 0; i < ArrayLength(mBrowserState.hapticState); i++) {
+    VRHapticState& state = mBrowserState.hapticState[i];
+    VRHapticState& lastState = mLastHapticState[i];
+    // Note that VRHapticState is asserted to be a POD type, thus memcmp is safe
+    if (memcmp(&state, &lastState, sizeof(VRHapticState)) == 0) {
+      // No change since the last update
+      continue;
+    }
+    if (state.inputFrameID == 0) {
+      // The haptic feedback was stopped
+      mSession->StopVibrateHaptic(state.controllerIndex);
+    } else {
+      TimeStamp now;
+      if (now.IsNull()) {
+        // TimeStamp::Now() is expensive, so we
+        // must call it only when needed and save the
+        // output for further loop iterations.
+        now = TimeStamp::Now();
+      }
+      // This is a new haptic pulse, or we are overriding a prior one
+      size_t historyIndex = state.inputFrameID % ArrayLength(mFrameStartTime);
+      float startOffset =
+          (float)(now - mFrameStartTime[historyIndex]).ToSeconds();
+
+      // state.pulseStart is guaranteed never to be in the future
+      mSession->VibrateHaptic(
+          state.controllerIndex, state.hapticIndex, state.pulseIntensity,
+          state.pulseDuration + state.pulseStart - startOffset);
+    }
+    // Record the state for comparison in the next run
+    memcpy(&lastState, &state, sizeof(VRHapticState));
+  }
+}
+
+void VRService::PushState(const mozilla::gfx::VRSystemState& aState) {
+  if (mShmem != nullptr) {
+    mShmem->PushSystemState(aState);
+  }
+}
+
+void VRService::PullState(mozilla::gfx::VRBrowserState& aState) {
+  if (mShmem != nullptr) {
+    mShmem->PullBrowserState(aState);
+  }
+}