1 /* 2 * Copyright 2019 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 #include "api/task_queue/task_queue_base.h" 11 12 #include "absl/base/attributes.h" 13 #include "absl/base/config.h" 14 #include "rtc_base/checks.h" 15 16 #if defined(ABSL_HAVE_THREAD_LOCAL) 17 18 namespace webrtc { 19 namespace { 20 21 ABSL_CONST_INIT thread_local TaskQueueBase* current = nullptr; 22 23 } // namespace 24 Current()25TaskQueueBase* TaskQueueBase::Current() { 26 return current; 27 } 28 CurrentTaskQueueSetter(TaskQueueBase * task_queue)29TaskQueueBase::CurrentTaskQueueSetter::CurrentTaskQueueSetter( 30 TaskQueueBase* task_queue) 31 : previous_(current) { 32 current = task_queue; 33 } 34 ~CurrentTaskQueueSetter()35TaskQueueBase::CurrentTaskQueueSetter::~CurrentTaskQueueSetter() { 36 current = previous_; 37 } 38 } // namespace webrtc 39 40 #elif defined(WEBRTC_POSIX) 41 42 #include <pthread.h> 43 44 namespace webrtc { 45 namespace { 46 47 ABSL_CONST_INIT pthread_key_t g_queue_ptr_tls = 0; 48 InitializeTls()49void InitializeTls() { 50 RTC_CHECK(pthread_key_create(&g_queue_ptr_tls, nullptr) == 0); 51 } 52 GetQueuePtrTls()53pthread_key_t GetQueuePtrTls() { 54 static pthread_once_t init_once = PTHREAD_ONCE_INIT; 55 RTC_CHECK(pthread_once(&init_once, &InitializeTls) == 0); 56 return g_queue_ptr_tls; 57 } 58 59 } // namespace 60 Current()61TaskQueueBase* TaskQueueBase::Current() { 62 return static_cast<TaskQueueBase*>(pthread_getspecific(GetQueuePtrTls())); 63 } 64 CurrentTaskQueueSetter(TaskQueueBase * task_queue)65TaskQueueBase::CurrentTaskQueueSetter::CurrentTaskQueueSetter( 66 TaskQueueBase* task_queue) 67 : previous_(TaskQueueBase::Current()) { 68 pthread_setspecific(GetQueuePtrTls(), task_queue); 69 } 70 ~CurrentTaskQueueSetter()71TaskQueueBase::CurrentTaskQueueSetter::~CurrentTaskQueueSetter() { 72 pthread_setspecific(GetQueuePtrTls(), previous_); 73 } 74 75 } // namespace webrtc 76 77 #else 78 #error Unsupported platform 79 #endif 80