1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16#ifndef ANDROID_HIDL_TASK_RUNNER_H
17#define ANDROID_HIDL_TASK_RUNNER_H
18
19#include "SynchronizedQueue.h"
20#include <memory>
21#include <thread>
22
23namespace android {
24namespace hardware {
25namespace details {
26
27/*
28 * A background infinite loop that runs the Tasks push()'ed.
29 * Equivalent to a simple single-threaded Looper.
30 */
31class TaskRunner {
32public:
33    using Task = std::function<void(void)>;
34
35    /* Create an empty task runner. Nothing will be done until start() is called. */
36    TaskRunner();
37
38    /*
39     * Notify the background thread to terminate and return immediately.
40     * Tasks in the queue will continue to be done sequentially in background
41     * until all tasks are finished.
42     */
43    ~TaskRunner();
44
45    /*
46     * Sets the queue limit. Fails the push operation once the limit is reached.
47     * Then kicks off the loop.
48     */
49    void start(size_t limit);
50
51    /*
52     * Add a task. Return true if successful, false if
53     * the queue's size exceeds limit or t doesn't contain a callable target.
54     */
55    bool push(const Task &t);
56
57private:
58    std::shared_ptr<SynchronizedQueue<Task>> mQueue;
59};
60
61} // namespace details
62} // namespace hardware
63} // namespace android
64
65#endif // ANDROID_HIDL_TASK_RUNNER_H
66