-- 972333fe1e43427849b8a634aa35061e81be3642 by Abseil Team <absl-team@google.com>: Replace deprecated thread annotations macros. PiperOrigin-RevId: 267332619 -- 7039c6dc499a31c372b4872eda0772455931c360 by Gennadiy Rozental <rogeeff@google.com>: Internal change PiperOrigin-RevId: 267220271 -- a3f524d2afc2535686f206a7ce06961016349d7a by Abseil Team <absl-team@google.com>: Factor kernel_timeout out of synchronization. PiperOrigin-RevId: 267217304 -- 90287de4114ef9a06cafe50256a2d03349772c21 by Abseil Team <absl-team@google.com>: Fixed comment typo. PiperOrigin-RevId: 267198532 -- d312c1a1e52aeca1871ff0deead416d09a7f237e by Gennadiy Rozental <rogeeff@google.com>: Internal change PiperOrigin-RevId: 267185804 GitOrigin-RevId: 972333fe1e43427849b8a634aa35061e81be3642 Change-Id: Ia8a2f877c57cef9854aad48f1753af872fc04dc8
		
			
				
	
	
		
			91 lines
		
	
	
	
		
			2.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			91 lines
		
	
	
	
		
			2.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
// Copyright 2017 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_
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#define ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_
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#include <cassert>
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#include <cstddef>
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#include <functional>
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#include <queue>
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#include <thread>  // NOLINT(build/c++11)
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#include <vector>
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#include "absl/base/thread_annotations.h"
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#include "absl/synchronization/mutex.h"
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namespace absl {
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namespace synchronization_internal {
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// A simple ThreadPool implementation for tests.
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class ThreadPool {
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 public:
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  explicit ThreadPool(int num_threads) {
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    for (int i = 0; i < num_threads; ++i) {
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      threads_.push_back(std::thread(&ThreadPool::WorkLoop, this));
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    }
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  }
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  ThreadPool(const ThreadPool &) = delete;
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  ThreadPool &operator=(const ThreadPool &) = delete;
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  ~ThreadPool() {
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    {
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      absl::MutexLock l(&mu_);
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      for (size_t i = 0; i < threads_.size(); i++) {
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        queue_.push(nullptr);  // Shutdown signal.
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      }
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    }
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    for (auto &t : threads_) {
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      t.join();
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    }
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  }
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  // Schedule a function to be run on a ThreadPool thread immediately.
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  void Schedule(std::function<void()> func) {
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    assert(func != nullptr);
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    absl::MutexLock l(&mu_);
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    queue_.push(std::move(func));
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  }
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 private:
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  bool WorkAvailable() const ABSL_EXCLUSIVE_LOCKS_REQUIRED(mu_) {
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    return !queue_.empty();
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  }
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  void WorkLoop() {
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    while (true) {
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      std::function<void()> func;
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      {
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        absl::MutexLock l(&mu_);
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        mu_.Await(absl::Condition(this, &ThreadPool::WorkAvailable));
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        func = std::move(queue_.front());
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        queue_.pop();
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      }
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      if (func == nullptr) {  // Shutdown signal.
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        break;
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      }
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      func();
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    }
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  }
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  absl::Mutex mu_;
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  std::queue<std::function<void()>> queue_ ABSL_GUARDED_BY(mu_);
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  std::vector<std::thread> threads_;
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};
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}  // namespace synchronization_internal
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}  // namespace absl
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#endif  // ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_
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