Prevent app from accessing the GPU in the background in MultiFrameCodec

Author: ColdPaleLight

lib/ui/fixtures/ui_test.dart

@@ -197,8 +197,8 @@ void createPath() {
 void _validatePath(Path path) native 'ValidatePath';
 
 @pragma('vm:entry-point')
-void frameCallback(FrameInfo info) {
-  print('called back');
+void frameCallback(_Image, int) {
+   print('called back');
 }
 
 @pragma('vm:entry-point')

lib/ui/painting/image_decoder_unittests.cc

@@ -731,5 +731,94 @@ TEST_F(ImageDecoderFixtureTest,
   latch.Wait();
 }
 
+TEST_F(ImageDecoderFixtureTest, MultiFrameCodecDidAccessGpuDisabledSyncSwitch) {
+  auto settings = CreateSettingsForFixture();
+  auto vm_ref = DartVMRef::Create(settings);
+  auto vm_data = vm_ref.GetVMData();
+
+  auto gif_mapping = OpenFixtureAsSkData("hello_loop_2.gif");
+
+  ASSERT_TRUE(gif_mapping);
+
+  ImageGeneratorRegistry registry;
+  std::shared_ptr<ImageGenerator> gif_generator =
+      registry.CreateCompatibleGenerator(gif_mapping);
+  ASSERT_TRUE(gif_generator);
+
+  TaskRunners runners(GetCurrentTestName(),         // label
+                      CreateNewThread("platform"),  // platform
+                      CreateNewThread("raster"),    // raster
+                      CreateNewThread("ui"),        // ui
+                      CreateNewThread("io")         // io
+  );
+
+  fml::AutoResetWaitableEvent latch;
+  std::unique_ptr<TestIOManager> io_manager;
+  fml::RefPtr<MultiFrameCodec> codec;
+
+  // Setup the IO manager.
+  runners.GetIOTaskRunner()->PostTask([&]() {
+    io_manager = std::make_unique<TestIOManager>(runners.GetIOTaskRunner());
+    latch.Signal();
+  });
+  latch.Wait();
+
+  auto isolate = RunDartCodeInIsolate(vm_ref, settings, runners, "main", {},
+                                      GetDefaultKernelFilePath(),
+                                      io_manager->GetWeakIOManager());
+
+  runners.GetUITaskRunner()->PostTask([&]() {
+    fml::AutoResetWaitableEvent isolate_latch;
+
+    EXPECT_TRUE(isolate->RunInIsolateScope([&]() -> bool {
+      Dart_Handle library = Dart_RootLibrary();
+      if (Dart_IsError(library)) {
+        isolate_latch.Signal();
+        return false;
+      }
+      Dart_Handle closure =
+          Dart_GetField(library, Dart_NewStringFromCString("frameCallback"));
+      if (Dart_IsError(closure) || !Dart_IsClosure(closure)) {
+        isolate_latch.Signal();
+        return false;
+      }
+
+      EXPECT_FALSE(io_manager->did_access_is_gpu_disabled_sync_switch_);
+      codec = fml::MakeRefCounted<MultiFrameCodec>(std::move(gif_generator));
+      codec->getNextFrame(closure);
+      isolate_latch.Signal();
+      return true;
+    }));
+    isolate_latch.Wait();
+
+    latch.Signal();
+  });
+  latch.Wait();
+
+  runners.GetIOTaskRunner()->PostTask([&]() {
+    EXPECT_TRUE(io_manager->did_access_is_gpu_disabled_sync_switch_);
+    latch.Signal();
+  });
+  latch.Wait();
+
+  // Destroy the Isolate
+  isolate = nullptr;
+
+  // Destroy the MultiFrameCodec
+  runners.GetUITaskRunner()->PostTask([&]() {
+    codec = nullptr;
+    latch.Signal();
+  });
+  latch.Wait();
+
+  // Destroy the IO manager
+  runners.GetIOTaskRunner()->PostTask([&]() {
+    io_manager.reset();
+    latch.Signal();
+  });
+
+  latch.Wait();
+}
+
 }  // namespace testing
 }  // namespace flutter

lib/ui/painting/multi_frame_codec.cc

@@ -76,7 +76,8 @@ static bool CopyToBitmap(SkBitmap* dst,
 }
 
 sk_sp<SkImage> MultiFrameCodec::State::GetNextFrameImage(
-    fml::WeakPtr<GrDirectContext> resourceContext) {
+    fml::WeakPtr<GrDirectContext> resourceContext,
+    const std::shared_ptr<const fml::SyncSwitch>& gpu_disable_sync_switch) {
   SkBitmap bitmap = SkBitmap();
   SkImageInfo info = generator_->GetInfo().makeColorType(kN32_SkColorType);
   if (info.alphaType() == kUnpremul_SkAlphaType) {
@@ -122,29 +123,40 @@ sk_sp<SkImage> MultiFrameCodec::State::GetNextFrameImage(
     lastRequiredFrame_ = std::make_unique<SkBitmap>(bitmap);
     lastRequiredFrameIndex_ = nextFrameIndex_;
   }
-
-  if (resourceContext) {
-    SkPixmap pixmap(bitmap.info(), bitmap.pixelRef()->pixels(),
-                    bitmap.pixelRef()->rowBytes());
-    return SkImage::MakeCrossContextFromPixmap(resourceContext.get(), pixmap,
-                                               true);
-  } else {
-    // Defer decoding until time of draw later on the raster thread. Can happen
-    // when GL operations are currently forbidden such as in the background
-    // on iOS.
-    return SkImage::MakeFromBitmap(bitmap);
-  }
+  sk_sp<SkImage> result;
+
+  gpu_disable_sync_switch->Execute(
+      fml::SyncSwitch::Handlers()
+          .SetIfTrue([&result, &bitmap] {
+            // Defer decoding until time of draw later on the raster thread. Can
+            // happen when GL operations are currently forbidden such as in the
+            // background on iOS.
+            result = SkImage::MakeFromBitmap(bitmap);
+          })
+          .SetIfFalse([&result, &resourceContext, &bitmap] {
+            if (resourceContext) {
+              SkPixmap pixmap(bitmap.info(), bitmap.pixelRef()->pixels(),
+                              bitmap.pixelRef()->rowBytes());
+              result = SkImage::MakeCrossContextFromPixmap(
+                  resourceContext.get(), pixmap, true);
+            } else {
+              result = SkImage::MakeFromBitmap(bitmap);
+            }
+          }));
+  return result;
 }
 
 void MultiFrameCodec::State::GetNextFrameAndInvokeCallback(
     std::unique_ptr<DartPersistentValue> callback,
     fml::RefPtr<fml::TaskRunner> ui_task_runner,
     fml::WeakPtr<GrDirectContext> resourceContext,
     fml::RefPtr<flutter::SkiaUnrefQueue> unref_queue,
+    const std::shared_ptr<const fml::SyncSwitch>& gpu_disable_sync_switch,
     size_t trace_id) {
   fml::RefPtr<CanvasImage> image = nullptr;
   int duration = 0;
-  sk_sp<SkImage> skImage = GetNextFrameImage(resourceContext);
+  sk_sp<SkImage> skImage =
+      GetNextFrameImage(resourceContext, gpu_disable_sync_switch);
   if (skImage) {
     image = CanvasImage::Create();
     image->set_image({skImage, std::move(unref_queue)});
@@ -200,7 +212,7 @@ Dart_Handle MultiFrameCodec::getNextFrame(Dart_Handle callback_handle) {
         state->GetNextFrameAndInvokeCallback(
             std::move(callback), std::move(ui_task_runner),
             io_manager->GetResourceContext(), io_manager->GetSkiaUnrefQueue(),
-            trace_id);
+            io_manager->GetIsGpuDisabledSyncSwitch(), trace_id);
       }));
 
   return Dart_Null();

lib/ui/painting/multi_frame_codec.h

@@ -54,13 +54,15 @@ class MultiFrameCodec : public Codec {
     int lastRequiredFrameIndex_ = -1;
 
     sk_sp<SkImage> GetNextFrameImage(
-        fml::WeakPtr<GrDirectContext> resourceContext);
+        fml::WeakPtr<GrDirectContext> resourceContext,
+        const std::shared_ptr<const fml::SyncSwitch>& gpu_disable_sync_switch);
 
     void GetNextFrameAndInvokeCallback(
         std::unique_ptr<DartPersistentValue> callback,
         fml::RefPtr<fml::TaskRunner> ui_task_runner,
         fml::WeakPtr<GrDirectContext> resourceContext,
         fml::RefPtr<flutter::SkiaUnrefQueue> unref_queue,
+        const std::shared_ptr<const fml::SyncSwitch>& gpu_disable_sync_switch,
         size_t trace_id);
   };