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/*
* Copyright (C) 2020 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 <platform/api/task_runner.h>
#include <atomic>
#include <condition_variable>
#include <map>
#include <mutex>
#include <optional>
#include <thread>
#include <android-base/thread_annotations.h>
namespace mdns {
// Openscreen API surface that allows for posting tasks. The underlying
// implementation may be single or multi-threaded, and all complication should
// be handled by the implementation class. The implementation must guarantee:
// (1) Tasks shall not overlap in time/CPU.
// (2) Tasks shall run sequentially, e.g. posting task A then B implies
// that A shall run before B.
// (3) If task A is posted before task B, then any mutation in A happens-before
// B runs (even if A and B run on different threads).
//
// Adb implementation: The PostPackagedTask* APIs are thread-safe.
// Another thread will handle dequeuing each item and calling it on the fdevent thread.
// Thus, the task runner thread is the fdevent thread, and IsRunningOnTaskRunner() shall always
// return true if calling from within the running Task.
class AdbOspTaskRunner final : public openscreen::TaskRunner {
public:
using Task = openscreen::TaskRunner::Task;
// Must be called on the fdevent thread.
explicit AdbOspTaskRunner();
~AdbOspTaskRunner() final;
void PostPackagedTask(Task task) final;
void PostPackagedTaskWithDelay(Task task, openscreen::Clock::duration delay) final;
bool IsRunningOnTaskRunner() final;
// The task executor thread.
void TaskExecutorWorker();
private:
uint64_t thread_id_;
std::mutex mutex_;
std::multimap<std::chrono::time_point<std::chrono::steady_clock>, Task> tasks_
GUARDED_BY(mutex_);
std::atomic<bool> terminate_loop_ = false;
std::condition_variable cv_;
std::thread task_handler_;
};
} // namespace mdns
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