1 /* 2 * Copyright (C) 2019 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 17 #include "perfetto/base/thread_task_runner.h" 18 19 #include <condition_variable> 20 #include <functional> 21 #include <mutex> 22 #include <thread> 23 24 #include "perfetto/base/logging.h" 25 #include "perfetto/base/unix_task_runner.h" 26 27 namespace perfetto { 28 namespace base { 29 30 ThreadTaskRunner::ThreadTaskRunner(ThreadTaskRunner&& other) noexcept 31 : thread_(std::move(other.thread_)), task_runner_(other.task_runner_) { 32 other.task_runner_ = nullptr; 33 } 34 35 ThreadTaskRunner& ThreadTaskRunner::operator=(ThreadTaskRunner&& other) { 36 this->~ThreadTaskRunner(); 37 new (this) ThreadTaskRunner(std::move(other)); 38 return *this; 39 } 40 41 ThreadTaskRunner::~ThreadTaskRunner() { 42 if (task_runner_) { 43 PERFETTO_CHECK(!task_runner_->QuitCalled()); 44 task_runner_->Quit(); 45 46 PERFETTO_DCHECK(thread_.joinable()); 47 } 48 if (thread_.joinable()) 49 thread_.join(); 50 } 51 52 ThreadTaskRunner::ThreadTaskRunner() { 53 std::mutex init_lock; 54 std::condition_variable init_cv; 55 56 std::function<void(UnixTaskRunner*)> initializer = 57 [this, &init_lock, &init_cv](UnixTaskRunner* task_runner) { 58 std::lock_guard<std::mutex> lock(init_lock); 59 task_runner_ = task_runner; 60 // Notify while still holding the lock, as init_cv ceases to exist as 61 // soon as the main thread observes a non-null task_runner_, and it can 62 // wake up spuriously (i.e. before the notify if we had unlocked before 63 // notifying). 64 init_cv.notify_one(); 65 }; 66 thread_ = std::thread(&ThreadTaskRunner::RunTaskThread, this, 67 std::move(initializer)); 68 69 std::unique_lock<std::mutex> lock(init_lock); 70 init_cv.wait(lock, [this] { return !!task_runner_; }); 71 } 72 73 void ThreadTaskRunner::RunTaskThread( 74 std::function<void(UnixTaskRunner*)> initializer) { 75 UnixTaskRunner task_runner; 76 task_runner.PostTask(std::bind(std::move(initializer), &task_runner)); 77 task_runner.Run(); 78 } 79 80 } // namespace base 81 } // namespace perfetto 82
