xref: /aosp_15_r20/external/webrtc/api/task_queue/task_queue_base.cc (revision d9f758449e529ab9291ac668be2861e7a55c2422) 
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 "absl/functional/any_invocable.h"
15 #include "api/units/time_delta.h"
16 #include "rtc_base/checks.h"
17 
18 #if defined(ABSL_HAVE_THREAD_LOCAL)
19 
20 namespace webrtc {
21 namespace {
22 
23 ABSL_CONST_INIT thread_local TaskQueueBase* current = nullptr;
24 
25 }  // namespace
26 
Current()27 TaskQueueBase* TaskQueueBase::Current() {
28   return current;
29 }
30 
CurrentTaskQueueSetter(TaskQueueBase * task_queue)31 TaskQueueBase::CurrentTaskQueueSetter::CurrentTaskQueueSetter(
32     TaskQueueBase* task_queue)
33     : previous_(current) {
34   current = task_queue;
35 }
36 
~CurrentTaskQueueSetter()37 TaskQueueBase::CurrentTaskQueueSetter::~CurrentTaskQueueSetter() {
38   current = previous_;
39 }
40 }  // namespace webrtc
41 
42 #elif defined(WEBRTC_POSIX)
43 
44 #include <pthread.h>
45 
46 namespace webrtc {
47 namespace {
48 
49 ABSL_CONST_INIT pthread_key_t g_queue_ptr_tls = 0;
50 
InitializeTls()51 void InitializeTls() {
52   RTC_CHECK(pthread_key_create(&g_queue_ptr_tls, nullptr) == 0);
53 }
54 
GetQueuePtrTls()55 pthread_key_t GetQueuePtrTls() {
56   static pthread_once_t init_once = PTHREAD_ONCE_INIT;
57   RTC_CHECK(pthread_once(&init_once, &InitializeTls) == 0);
58   return g_queue_ptr_tls;
59 }
60 
61 }  // namespace
62 
Current()63 TaskQueueBase* TaskQueueBase::Current() {
64   return static_cast<TaskQueueBase*>(pthread_getspecific(GetQueuePtrTls()));
65 }
66 
CurrentTaskQueueSetter(TaskQueueBase * task_queue)67 TaskQueueBase::CurrentTaskQueueSetter::CurrentTaskQueueSetter(
68     TaskQueueBase* task_queue)
69     : previous_(TaskQueueBase::Current()) {
70   pthread_setspecific(GetQueuePtrTls(), task_queue);
71 }
72 
~CurrentTaskQueueSetter()73 TaskQueueBase::CurrentTaskQueueSetter::~CurrentTaskQueueSetter() {
74   pthread_setspecific(GetQueuePtrTls(), previous_);
75 }
76 
77 }  // namespace webrtc
78 
79 #else
80 #error Unsupported platform
81 #endif
82