SF: Introduce background task executor
Extract logic to execute work outside of the main thread
from TransactionCallbackInvoker so we can reuse the
thread for other tasks that are not critical to drawing.
Bug: 206380307
Test: presubmit
Change-Id: I8128d2f333e3aab5639cd1200e820de39f0b3191
diff --git a/services/surfaceflinger/BackgroundExecutor.h b/services/surfaceflinger/BackgroundExecutor.h
new file mode 100644
index 0000000..6f6d305
--- /dev/null
+++ b/services/surfaceflinger/BackgroundExecutor.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <utils/Singleton.h>
+#include <condition_variable>
+#include <mutex>
+#include <queue>
+#include <thread>
+
+namespace android {
+
+// Executes tasks off the main thread.
+class BackgroundExecutor : public Singleton<BackgroundExecutor> {
+public:
+ BackgroundExecutor();
+ ~BackgroundExecutor();
+ void execute(std::function<void()>);
+
+private:
+ std::mutex mMutex;
+ std::condition_variable mWorkAvailableCv;
+ std::thread mThread;
+ bool mDone = false;
+ std::vector<std::function<void()>> mTasks;
+};
+
+} // namespace android