12bc53e031
-- c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>: Remove a floating point division by zero test. This isn't testing behavior related to the library, and MSVC warns about it in opt mode. PiperOrigin-RevId: 285220804 -- 68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>: This CL introduces following changes to the class FlagImpl: * We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately. * CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now. * Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call. * We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced. PiperOrigin-RevId: 285132636 -- ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>: Change null-term* (and nul-term*) to NUL-term* in comments PiperOrigin-RevId: 285036610 -- 729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>: Use the Posix implementation of thread identity on MinGW. Some versions of MinGW suffer from thread_local bugs. PiperOrigin-RevId: 285022920 -- 39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>: Implementation detail change. Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil. PiperOrigin-RevId: 285012012 GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
93 lines
2.5 KiB
C++
93 lines
2.5 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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ABSL_NAMESPACE_BEGIN
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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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ABSL_NAMESPACE_END
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} // namespace absl
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#endif // ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_
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