Bug 774388 - Patch 4: Flatten the way that we track whether we are using OMTC, and move Layers IPC shutdown code back to gfxPlatform (but still triggered by ShutdownXPCOM) - r=nical,sotaro

dom/ipc/ContentParent.cpp

@@ -1710,8 +1710,7 @@ ContentParent::InitInternal(ProcessPriority aInitialPriority,
         // PBrowsers are created, because they rely on the Compositor
         // already being around.  (Creation is async, so can't happen
         // on demand.)
-        bool useOffMainThreadCompositing = !!CompositorParent::CompositorLoop();
-        if (useOffMainThreadCompositing) {
+        if (gfxPlatform::UsesOffMainThreadCompositing()) {
             DebugOnly<bool> opened = PCompositor::Open(this);
             MOZ_ASSERT(opened);
 

dom/ipc/TabParent.cpp

@@ -1888,9 +1888,9 @@ TabParent::GetWidget() const
 bool
 TabParent::UseAsyncPanZoom()
 {
-  bool usingOffMainThreadCompositing = !!CompositorParent::CompositorLoop();
-  return (usingOffMainThreadCompositing && gfxPrefs::AsyncPanZoomEnabled() &&
-          GetScrollingBehavior() == ASYNC_PAN_ZOOM);
+  return gfxPlatform::UsesOffMainThreadCompositing() &&
+         gfxPrefs::AsyncPanZoomEnabled() &&
+         GetScrollingBehavior() == ASYNC_PAN_ZOOM;
 }
 
 nsEventStatus

gfx/thebes/gfxPlatform.cpp

@@ -277,6 +277,9 @@ gfxPlatform::gfxPlatform()
     uint32_t contentMask = BackendTypeBit(BackendType::CAIRO);
     InitBackendPrefs(canvasMask, BackendType::CAIRO,
                      contentMask, BackendType::CAIRO);
+
+    mUsesOffMainThreadCompositing = ComputeUsesOffMainThreadCompositing();
+    mAlreadyShutDownLayersIPC = false;
 }
 
 gfxPlatform*
@@ -364,17 +367,12 @@ gfxPlatform::Init()
     mozilla::gl::GLContext::StaticInit();
 #endif
 
-    bool useOffMainThreadCompositing = OffMainThreadCompositionRequired() ||
-                                       GetPrefLayersOffMainThreadCompositionEnabled();
-
-    if (!OffMainThreadCompositionRequired()) {
-      useOffMainThreadCompositing &= GetPlatform()->SupportsOffMainThreadCompositing();
-    }
-
-    if (useOffMainThreadCompositing && (XRE_GetProcessType() == GeckoProcessType_Default)) {
-        CompositorParent::StartUp();
+    if (UsesOffMainThreadCompositing() &&
+        XRE_GetProcessType() == GeckoProcessType_Default)
+    {
+        mozilla::layers::CompositorParent::StartUp();
         if (gfxPrefs::AsyncVideoEnabled()) {
-            ImageBridgeChild::StartUp();
+            mozilla::layers::ImageBridgeChild::StartUp();
         }
 #ifdef MOZ_WIDGET_GONK
         SharedBufferManagerChild::StartUp();
@@ -444,6 +442,9 @@ gfxPlatform::Init()
 void
 gfxPlatform::Shutdown()
 {
+    MOZ_ASSERT(gPlatform, "gfxPlatform already down!");
+    MOZ_ASSERT(gPlatform->mAlreadyShutDownLayersIPC, "ShutdownLayersIPC should have been called before this point!");
+
     // These may be called before the corresponding subsystems have actually
     // started up. That's OK, they can handle it.
     gfxFontCache::Shutdown();
@@ -506,6 +507,25 @@ gfxPlatform::Shutdown()
     gPlatform = nullptr;
 }
 
+/* static */ void
+gfxPlatform::ShutdownLayersIPC()
+{
+    MOZ_ASSERT(!gPlatform->mAlreadyShutDownLayersIPC);
+    if (UsesOffMainThreadCompositing() &&
+        XRE_GetProcessType() == GeckoProcessType_Default)
+    {
+        // This must happen after the shutdown of media and widgets, which
+        // are triggered by the NS_XPCOM_SHUTDOWN_OBSERVER_ID notification.
+        layers::ImageBridgeChild::ShutDown();
+#ifdef MOZ_WIDGET_GONK
+        layers::SharedBufferManagerChild::ShutDown();
+#endif
+
+        layers::CompositorParent::ShutDown();
+    }
+    gPlatform->mAlreadyShutDownLayersIPC = true;
+}
+
 gfxPlatform::~gfxPlatform()
 {
     mScreenReferenceSurface = nullptr;
@@ -532,7 +552,6 @@ gfxPlatform::~gfxPlatform()
 
 bool
 gfxPlatform::PreferMemoryOverShmem() const {
-  MOZ_ASSERT(!CompositorParent::IsInCompositorThread());
   return mLayersPreferMemoryOverShmem;
 }
 
@@ -1542,9 +1561,7 @@ gfxPlatform::GetBackendPref(const char* aBackendPrefName, uint32_t &aBackendBitm
 bool
 gfxPlatform::OffMainThreadCompositingEnabled()
 {
-  return XRE_GetProcessType() == GeckoProcessType_Default ?
-    CompositorParent::CompositorLoop() != nullptr :
-    CompositorChild::ChildProcessHasCompositor();
+  return UsesOffMainThreadCompositing();
 }
 
 eCMSMode
@@ -2008,27 +2025,6 @@ InitLayersAccelerationPrefs()
   }
 }
 
-bool
-gfxPlatform::GetPrefLayersOffMainThreadCompositionEnabled()
-{
-  InitLayersAccelerationPrefs();
-  return gfxPrefs::LayersOffMainThreadCompositionEnabled() ||
-         gfxPrefs::LayersOffMainThreadCompositionForceEnabled() ||
-         gfxPrefs::LayersOffMainThreadCompositionTestingEnabled();
-}
-
-bool gfxPlatform::OffMainThreadCompositionRequired()
-{
-  InitLayersAccelerationPrefs();
-#if defined(MOZ_WIDGET_GTK) && defined(NIGHTLY_BUILD)
-  // Linux users who chose OpenGL are being grandfathered in to OMTC
-  return sPrefBrowserTabsRemoteAutostart ||
-         gfxPrefs::LayersAccelerationForceEnabled();
-#else
-  return sPrefBrowserTabsRemoteAutostart;
-#endif
-}
-
 bool
 gfxPlatform::CanUseDirect3D9()
 {
@@ -2075,3 +2071,25 @@ gfxPlatform::GetScaledFontForFontWithCairoSkia(DrawTarget* aTarget, gfxFont* aFo
 
     return nullptr;
 }
+
+bool
+gfxPlatform::ComputeUsesOffMainThreadCompositing()
+{
+  InitLayersAccelerationPrefs();
+  bool result =
+    sPrefBrowserTabsRemoteAutostart ||
+    gfxPrefs::LayersOffMainThreadCompositionEnabled() ||
+    gfxPrefs::LayersOffMainThreadCompositionForceEnabled() ||
+    gfxPrefs::LayersOffMainThreadCompositionTestingEnabled();
+#if defined(MOZ_WIDGET_GTK) && defined(NIGHTLY_BUILD)
+  // Linux users who chose OpenGL are being grandfathered in to OMTC
+  result |=
+    gfxPrefs::LayersAccelerationForceEnabled() ||
+    PR_GetEnv("MOZ_USE_OMTC") ||
+    PR_GetEnv("MOZ_OMTC_ENABLED"); // yeah, these two env vars do the same thing.
+                                   // I'm told that one of them is enabled on some test slaves config.
+                                   // so be slightly careful if you think you can
+                                   // remove one of them.
+#endif
+  return result;
+}

gfx/thebes/gfxPlatform.h

@@ -170,6 +170,8 @@ public:
      */
     static void Shutdown();
 
+    static void ShutdownLayersIPC();
+
     /**
      * Create an offscreen surface of the given dimensions
      * and image format.
@@ -433,16 +435,9 @@ public:
 
     static bool OffMainThreadCompositingEnabled();
 
-    /** Use gfxPlatform::GetPref* methods instead of direct calls to Preferences
-     * to get the values for layers preferences.  These will only be evaluated
-     * only once, and remain the same until restart.
-     */
-    static bool GetPrefLayersOffMainThreadCompositionEnabled();
     static bool CanUseDirect3D9();
     static bool CanUseDirect3D11();
 
-    static bool OffMainThreadCompositionRequired();
-
     /**
      * Is it possible to use buffer rotation.  Note that these
      * check the preference, but also allow for the override to
@@ -549,6 +544,10 @@ public:
 
     virtual bool IsInGonkEmulator() const { return false; }
 
+    static bool UsesOffMainThreadCompositing() {
+      return GetPlatform()->mUsesOffMainThreadCompositing;
+    }
+
 protected:
     gfxPlatform();
     virtual ~gfxPlatform();
@@ -618,6 +617,13 @@ protected:
     // max number of entries in word cache
     int32_t mWordCacheMaxEntries;
 
+    // Whether we use OMTC/OMPC (as opposed to main-thread compositing)
+    bool mUsesOffMainThreadCompositing;
+
+    // Whether ShutdownLayersIPC has alrady been called. Used to enforce that
+    // it is called before Shutdown.
+    bool mAlreadyShutDownLayersIPC;
+
 private:
     /**
      * Start up Thebes.
@@ -632,7 +638,7 @@ private:
 
     virtual void GetPlatformCMSOutputProfile(void *&mem, size_t &size);
 
-    virtual bool SupportsOffMainThreadCompositing() { return true; }
+    bool ComputeUsesOffMainThreadCompositing();
 
     nsRefPtr<gfxASurface> mScreenReferenceSurface;
     mozilla::RefPtr<mozilla::gfx::DrawTarget> mScreenReferenceDrawTarget;

gfx/thebes/gfxPlatformGtk.cpp

@@ -252,18 +252,6 @@ gfxPlatformGtk::GetScreenDepth() const
     return sDepth;
 }
 
-bool
-gfxPlatformGtk::SupportsOffMainThreadCompositing()
-{
-  // Nightly builds have OMTC support by default for Electrolysis testing.
-#if defined(MOZ_X11) && !defined(NIGHTLY_BUILD)
-  return (PR_GetEnv("MOZ_USE_OMTC") != nullptr) ||
-         (PR_GetEnv("MOZ_OMTC_ENABLED") != nullptr);
-#else
-  return true;
-#endif
-}
-
 void
 gfxPlatformGtk::GetPlatformCMSOutputProfile(void *&mem, size_t &size)
 {

gfx/thebes/gfxPlatformGtk.h

@@ -98,7 +98,6 @@ protected:
 private:
     virtual void GetPlatformCMSOutputProfile(void *&mem, size_t &size);
 
-    virtual bool SupportsOffMainThreadCompositing();
 #ifdef MOZ_X11
     static bool sUseXRender;
 #endif

gfx/thebes/gfxPlatformMac.cpp

@@ -435,12 +435,6 @@ gfxPlatformMac::UseAcceleratedCanvas()
   return nsCocoaFeatures::OnLionOrLater() && Preferences::GetBool("gfx.canvas.azure.accelerated", false);
 }
 
-bool
-gfxPlatformMac::SupportsOffMainThreadCompositing()
-{
-  return true;
-}
-
 void
 gfxPlatformMac::GetPlatformCMSOutputProfile(void* &mem, size_t &size)
 {

gfx/thebes/gfxPlatformMac.h

@@ -72,8 +72,6 @@ public:
 private:
     virtual void GetPlatformCMSOutputProfile(void* &mem, size_t &size);
 
-    virtual bool SupportsOffMainThreadCompositing();
-
     // read in the pref value for the lower threshold on font anti-aliasing
     static uint32_t ReadAntiAliasingThreshold();
 

gfx/thebes/gfxQtPlatform.cpp

@@ -160,17 +160,6 @@ gfxQtPlatform::MakePlatformFont(const gfxProxyFontEntry *aProxyEntry,
                                            aFontData, aLength);
 }
 
-bool
-gfxQtPlatform::SupportsOffMainThreadCompositing()
-{
-#if defined(MOZ_X11) && !defined(NIGHTLY_BUILD)
-  return (PR_GetEnv("MOZ_USE_OMTC") != nullptr) ||
-         (PR_GetEnv("MOZ_OMTC_ENABLED") != nullptr);
-#else
-  return true;
-#endif
-}
-
 bool
 gfxQtPlatform::IsFontFormatSupported(nsIURI *aFontURI, uint32_t aFormatFlags)
 {

gfx/thebes/gfxQtPlatform.h

@@ -83,8 +83,6 @@ public:
 
     virtual int GetScreenDepth() const MOZ_OVERRIDE;
 
-    virtual bool SupportsOffMainThreadCompositing() MOZ_OVERRIDE;
-
 protected:
     static gfxFontconfigUtils *sFontconfigUtils;
 

gfx/thebes/gfxWindowsPlatform.cpp

@@ -1380,8 +1380,8 @@ gfxWindowsPlatform::GetD3D9DeviceManager()
   // We should only create the d3d9 device on the compositor thread
   // or we don't have a compositor thread.
   if (!mDeviceManager &&
-      (CompositorParent::IsInCompositorThread() ||
-       !CompositorParent::CompositorLoop())) {
+      (!gfxPlatform::UsesOffMainThreadCompositing() ||
+       CompositorParent::IsInCompositorThread())) {
     mDeviceManager = new DeviceManagerD3D9();
     if (!mDeviceManager->Init()) {
       NS_WARNING("Could not initialise device manager");

layout/build/nsLayoutModule.cpp

@@ -71,7 +71,6 @@
 #include "nsDOMBlobBuilder.h"
 #include "nsDOMFileReader.h"
 
-#include "gfxPlatform.h"
 #include "nsFormData.h"
 #include "nsHostObjectProtocolHandler.h"
 #include "nsHostObjectURI.h"

layout/ipc/RenderFrameParent.cpp

@@ -737,7 +737,7 @@ RenderFrameParent::RenderFrameParent(nsFrameLoader* aFrameLoader,
     }
   }
 
-  if (CompositorParent::CompositorLoop()) {
+  if (gfxPlatform::UsesOffMainThreadCompositing()) {
     // Our remote frame will push layers updates to the compositor,
     // and we'll keep an indirect reference to that tree.
     *aId = mLayersId = CompositorParent::AllocateLayerTreeId();

widget/windows/winrt/MetroWidget.cpp

@@ -998,7 +998,8 @@ MetroWidget::ShouldUseOffMainThreadCompositing()
     return false;
   }
   // toolkit or test widgets can't use omtc, they don't have ICoreWindow.
-  return (CompositorParent::CompositorLoop() && mWindowType == eWindowType_toplevel);
+  return gfxPlatform::UsesOffMainThreadCompositing() &&
+         mWindowType == eWindowType_toplevel;
 }
 
 bool
@@ -1008,7 +1009,8 @@ MetroWidget::ShouldUseMainThreadD3D10Manager()
   if (!mView) {
     return false;
   }
-  return (!CompositorParent::CompositorLoop() && mWindowType == eWindowType_toplevel);
+  return !gfxPlatform::UsesOffMainThreadCompositing() &&
+         mWindowType == eWindowType_toplevel;
 }
 
 bool

widget/xpwidgets/nsBaseWidget.cpp

@@ -888,6 +888,9 @@ CheckForBasicBackends(nsTArray<LayersBackend>& aHints)
 
 void nsBaseWidget::CreateCompositor(int aWidth, int aHeight)
 {
+  MOZ_ASSERT(gfxPlatform::UsesOffMainThreadCompositing(),
+             "This function assumes OMTC");
+
   // Recreating this is tricky, as we may still have an old and we need
   // to make sure it's properly destroyed by calling DestroyCompositor!
 
@@ -946,7 +949,7 @@ void nsBaseWidget::CreateCompositor(int aWidth, int aHeight)
 
 bool nsBaseWidget::ShouldUseOffMainThreadCompositing()
 {
-  return CompositorParent::CompositorLoop();
+  return gfxPlatform::UsesOffMainThreadCompositing();
 }
 
 LayerManager* nsBaseWidget::GetLayerManager(PLayerTransactionChild* aShadowManager,

xpcom/build/nsXPComInit.cpp

@@ -149,6 +149,8 @@ extern nsresult nsStringInputStreamConstructor(nsISupports *, REFNSIID, void **)
 
 #include "jsapi.h"
 
+#include "gfxPlatform.h"
+
 using namespace mozilla;
 using base::AtExitManager;
 using mozilla::ipc::BrowserProcessSubThread;
@@ -797,13 +799,6 @@ ShutdownXPCOM(nsIServiceManager* servMgr)
             }
         }
 
-        // This must happen after the shutdown of media and widgets, which
-        // are triggered by the NS_XPCOM_SHUTDOWN_OBSERVER_ID notification.
-        layers::ImageBridgeChild::ShutDown();
-#ifdef MOZ_WIDGET_GONK
-        layers::SharedBufferManagerChild::ShutDown();
-#endif
-
         NS_ProcessPendingEvents(thread);
         mozilla::scache::StartupCache::DeleteSingleton();
         if (observerService)
@@ -811,7 +806,9 @@ ShutdownXPCOM(nsIServiceManager* servMgr)
                 NotifyObservers(nullptr, NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID,
                                 nullptr);
 
-        layers::CompositorParent::ShutDown();
+        // This must happen after the shutdown of media and widgets, which
+        // are triggered by the NS_XPCOM_SHUTDOWN_OBSERVER_ID notification.
+        gfxPlatform::ShutdownLayersIPC();
 
         gXPCOMThreadsShutDown = true;
         NS_ProcessPendingEvents(thread);