content/child/worker_thread_impl.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/child/worker_thread_impl.h"
   6
   7 #include "base/lazy_instance.h"
   8 #include "base/logging.h"
   9 #include "base/observer_list.h"
  10 #include "base/threading/thread_local.h"
  11 #include "content/child/worker_task_runner.h"
  12 #include "content/common/content_export.h"
  13 #include "content/public/child/worker_thread.h"
  14
  15 namespace content {
  16
  17 namespace {
  18
  19 using WorkerThreadObservers = base::ObserverList<WorkerThread::Observer>;
  20 using ThreadLocalWorkerThreadObservers =
  21     base::ThreadLocalPointer<WorkerThreadObservers>;
  22
  23 // Stores a WorkerThreadObservers instance per thread.
  24 base::LazyInstance<ThreadLocalWorkerThreadObservers> g_observers_tls =
  25     LAZY_INSTANCE_INITIALIZER;
  26
  27 }  // namespace
  28
  29 // WorkerThread:
  30
  31 // static
  32 int WorkerThread::GetCurrentId() {
  33   if (!g_observers_tls.Get().Get())
  34     return 0;
  35   return base::PlatformThread::CurrentId();
  36 }
  37
  38 // static
  39 void WorkerThread::PostTask(int id, const base::Closure& task) {
  40   WorkerTaskRunner::Instance()->PostTask(id, task);
  41 }
  42
  43 // static
  44 void WorkerThread::AddObserver(Observer* observer) {
  45   DCHECK(GetCurrentId() > 0);
  46   WorkerThreadObservers* observers = g_observers_tls.Get().Get();
  47   DCHECK(observers);
  48   observers->AddObserver(observer);
  49 }
  50
  51 // static
  52 void WorkerThread::RemoveObserver(Observer* observer) {
  53   DCHECK(GetCurrentId() > 0);
  54   WorkerThreadObservers* observers = g_observers_tls.Get().Get();
  55   DCHECK(observers);
  56   observers->RemoveObserver(observer);
  57 }
  58
  59 // WorkerThreadImpl:
  60
  61 // static
  62 void WorkerThreadImpl::DidStartCurrentWorkerThread() {
  63   ThreadLocalWorkerThreadObservers& observers_tls = g_observers_tls.Get();
  64   DCHECK(!observers_tls.Get());
  65   observers_tls.Set(new WorkerThreadObservers());
  66 }
  67
  68 // static
  69 void WorkerThreadImpl::WillStopCurrentWorkerThread() {
  70   ThreadLocalWorkerThreadObservers& observers_tls = g_observers_tls.Get();
  71   WorkerThreadObservers* observers = observers_tls.Get();
  72   DCHECK(observers);
  73   FOR_EACH_OBSERVER(WorkerThread::Observer, *observers,
  74                     WillStopCurrentWorkerThread());
  75   delete observers;
  76   observers_tls.Set(nullptr);
  77 }
  78
  79 }  // namespace content