83 lines
2.2 KiB
C++
83 lines
2.2 KiB
C++
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/*
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* Copyright 2019 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "rtc_base/synchronization/yield_policy.h"
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#include "absl/base/attributes.h"
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#include "absl/base/config.h"
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#include "rtc_base/checks.h"
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#if !defined(ABSL_HAVE_THREAD_LOCAL) && defined(WEBRTC_POSIX)
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#include <pthread.h>
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#endif
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namespace rtc {
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namespace {
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#if defined(ABSL_HAVE_THREAD_LOCAL)
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ABSL_CONST_INIT thread_local YieldInterface* current_yield_policy = nullptr;
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YieldInterface* GetCurrentYieldPolicy() {
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return current_yield_policy;
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}
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void SetCurrentYieldPolicy(YieldInterface* ptr) {
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current_yield_policy = ptr;
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}
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#elif defined(WEBRTC_POSIX)
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// Emscripten does not support the C++11 thread_local keyword but does support
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// the pthread thread-local storage API.
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// https://github.com/emscripten-core/emscripten/issues/3502
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ABSL_CONST_INIT pthread_key_t g_current_yield_policy_tls = 0;
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void InitializeTls() {
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RTC_CHECK_EQ(pthread_key_create(&g_current_yield_policy_tls, nullptr), 0);
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}
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pthread_key_t GetCurrentYieldPolicyTls() {
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static pthread_once_t init_once = PTHREAD_ONCE_INIT;
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RTC_CHECK_EQ(pthread_once(&init_once, &InitializeTls), 0);
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return g_current_yield_policy_tls;
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}
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YieldInterface* GetCurrentYieldPolicy() {
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return static_cast<YieldInterface*>(
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pthread_getspecific(GetCurrentYieldPolicyTls()));
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}
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void SetCurrentYieldPolicy(YieldInterface* ptr) {
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pthread_setspecific(GetCurrentYieldPolicyTls(), ptr);
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}
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#else
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#error Unsupported platform
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#endif
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} // namespace
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ScopedYieldPolicy::ScopedYieldPolicy(YieldInterface* policy)
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: previous_(GetCurrentYieldPolicy()) {
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SetCurrentYieldPolicy(policy);
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}
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ScopedYieldPolicy::~ScopedYieldPolicy() {
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SetCurrentYieldPolicy(previous_);
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}
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void ScopedYieldPolicy::YieldExecution() {
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YieldInterface* current = GetCurrentYieldPolicy();
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if (current)
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current->YieldExecution();
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}
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} // namespace rtc
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