diff options
Diffstat (limited to 'webrtc/rtc_base/synchronization/yield_policy.cc')
-rw-r--r-- | webrtc/rtc_base/synchronization/yield_policy.cc | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/webrtc/rtc_base/synchronization/yield_policy.cc b/webrtc/rtc_base/synchronization/yield_policy.cc new file mode 100644 index 0000000..d883d42 --- /dev/null +++ b/webrtc/rtc_base/synchronization/yield_policy.cc @@ -0,0 +1,82 @@ +/* + * Copyright 2019 The WebRTC project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ +#include "rtc_base/synchronization/yield_policy.h" + +#include "absl/base/attributes.h" +#include "absl/base/config.h" +#include "rtc_base/checks.h" +#if !defined(ABSL_HAVE_THREAD_LOCAL) && defined(WEBRTC_POSIX) +#include <pthread.h> +#endif + +namespace rtc { +namespace { + +#if defined(ABSL_HAVE_THREAD_LOCAL) + +ABSL_CONST_INIT thread_local YieldInterface* current_yield_policy = nullptr; + +YieldInterface* GetCurrentYieldPolicy() { + return current_yield_policy; +} + +void SetCurrentYieldPolicy(YieldInterface* ptr) { + current_yield_policy = ptr; +} + +#elif defined(WEBRTC_POSIX) + +// Emscripten does not support the C++11 thread_local keyword but does support +// the pthread thread-local storage API. +// https://github.com/emscripten-core/emscripten/issues/3502 + +ABSL_CONST_INIT pthread_key_t g_current_yield_policy_tls = 0; + +void InitializeTls() { + RTC_CHECK_EQ(pthread_key_create(&g_current_yield_policy_tls, nullptr), 0); +} + +pthread_key_t GetCurrentYieldPolicyTls() { + static pthread_once_t init_once = PTHREAD_ONCE_INIT; + RTC_CHECK_EQ(pthread_once(&init_once, &InitializeTls), 0); + return g_current_yield_policy_tls; +} + +YieldInterface* GetCurrentYieldPolicy() { + return static_cast<YieldInterface*>( + pthread_getspecific(GetCurrentYieldPolicyTls())); +} + +void SetCurrentYieldPolicy(YieldInterface* ptr) { + pthread_setspecific(GetCurrentYieldPolicyTls(), ptr); +} + +#else +#error Unsupported platform +#endif + +} // namespace + +ScopedYieldPolicy::ScopedYieldPolicy(YieldInterface* policy) + : previous_(GetCurrentYieldPolicy()) { + SetCurrentYieldPolicy(policy); +} + +ScopedYieldPolicy::~ScopedYieldPolicy() { + SetCurrentYieldPolicy(previous_); +} + +void ScopedYieldPolicy::YieldExecution() { + YieldInterface* current = GetCurrentYieldPolicy(); + if (current) + current->YieldExecution(); +} + +} // namespace rtc |