Add TaskManager API
This API can be used to run arbitrary tasks on a pool of worker
threads. The number of threads is calculated based on the number
of CPU cores available.
The API is made of 3 classes:
TaskManager
Creates and manages the worker threads.
Task
Describes the work to be done and the type of the output.
A task contains a future used to wait for the worker thread
to be done computing the result of the task.
TaskProcessor
The processor dispatches tasks to the TaskManager and is
responsible for performing the computation required by
each task. A processor will only be asked to process tasks
sent to the manager through the processor.
A typical use case:
class MyTask: Task<MyType>
class MyProcessor: TaskProcessor<MyType>
TaskManager m = new TaskManager();
MyProcessor p = new MyProcessor(m);
MyTask t = new MyTask();
p.add(t);
// Waits until the result is available
MyType result = t->getResult();
Change-Id: I1fe845ba4c49bb0e1b0627ab147f9a861c8e0749
diff --git a/libs/hwui/thread/TaskManager.h b/libs/hwui/thread/TaskManager.h
new file mode 100644
index 0000000..bc86062
--- /dev/null
+++ b/libs/hwui/thread/TaskManager.h
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef ANDROID_HWUI_TASK_MANAGER_H
+#define ANDROID_HWUI_TASK_MANAGER_H
+
+#include <utils/Mutex.h>
+#include <utils/String8.h>
+#include <utils/Thread.h>
+#include <utils/Vector.h>
+
+#include "Signal.h"
+
+namespace android {
+namespace uirenderer {
+
+template <typename T>
+class Task;
+class TaskBase;
+
+template <typename T>
+class TaskProcessor;
+class TaskProcessorBase;
+
+class TaskManager {
+public:
+ TaskManager();
+ ~TaskManager();
+
+ /**
+ * Returns true if this task manager can run tasks,
+ * false otherwise. This method will typically return
+ * true on a single CPU core device.
+ */
+ bool canRunTasks() const;
+
+private:
+ template <typename T>
+ friend class TaskProcessor;
+
+ template<typename T>
+ bool addTask(const sp<Task<T> >& task, const sp<TaskProcessor<T> >& processor) {
+ return addTaskBase(sp<TaskBase>(task), sp<TaskProcessorBase>(processor));
+ }
+
+ bool addTaskBase(const sp<TaskBase>& task, const sp<TaskProcessorBase>& processor);
+
+ struct TaskWrapper {
+ TaskWrapper(): mTask(), mProcessor() { }
+
+ TaskWrapper(const sp<TaskBase>& task, const sp<TaskProcessorBase>& processor):
+ mTask(task), mProcessor(processor) {
+ }
+
+ sp<TaskBase> mTask;
+ sp<TaskProcessorBase> mProcessor;
+ };
+
+ class WorkerThread: public Thread {
+ public:
+ WorkerThread(const String8 name): mSignal(Condition::WAKE_UP_ONE), mName(name) { }
+
+ bool addTask(TaskWrapper task);
+ size_t getTaskCount() const;
+ void exit();
+
+ private:
+ virtual bool threadLoop();
+
+ // Lock for the list of tasks
+ mutable Mutex mLock;
+ Vector<TaskWrapper> mTasks;
+
+ // Signal used to wake up the thread when a new
+ // task is available in the list
+ mutable Signal mSignal;
+
+ const String8 mName;
+ };
+
+ Vector<sp<WorkerThread> > mThreads;
+};
+
+}; // namespace uirenderer
+}; // namespace android
+
+#endif // ANDROID_HWUI_TASK_MANAGER_H