third_party/WebKit/Source/platform/WebThreadSupportingGC.cpp

   1 // Copyright 2014 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 "config.h"
   6 #include "platform/WebThreadSupportingGC.h"
   7
   8 #include "platform/heap/SafePoint.h"
   9 #include "public/platform/WebScheduler.h"
  10 #include "wtf/Threading.h"
  11
  12 namespace blink {
  13
  14 PassOwnPtr<WebThreadSupportingGC> WebThreadSupportingGC::create(const char* name)
  15 {
  16     return adoptPtr(new WebThreadSupportingGC(name, nullptr));
  17 }
  18
  19 PassOwnPtr<WebThreadSupportingGC> WebThreadSupportingGC::createForThread(WebThread* thread)
  20 {
  21     return adoptPtr(new WebThreadSupportingGC(nullptr, thread));
  22 }
  23
  24 WebThreadSupportingGC::WebThreadSupportingGC(const char* name, WebThread* thread)
  25     : m_thread(thread)
  26 {
  27 #if ENABLE(ASSERT)
  28     ASSERT(!name || !thread);
  29     // We call this regardless of whether an existing thread is given or not,
  30     // as it means that blink is going to run with more than one thread.
  31     WTF::willCreateThread();
  32 #endif
  33     if (!m_thread) {
  34         // If |thread| is not given, create a new one and own it.
  35         m_owningThread = adoptPtr(Platform::current()->createThread(name));
  36         m_thread = m_owningThread.get();
  37     }
  38 }
  39
  40 WebThreadSupportingGC::~WebThreadSupportingGC()
  41 {
  42     if (ThreadState::current() && m_owningThread) {
  43         // WebThread's destructor blocks until all the tasks are processed.
  44         SafePointScope scope(ThreadState::HeapPointersOnStack);
  45         m_owningThread.clear();
  46     }
  47 }
  48
  49 void WebThreadSupportingGC::initialize()
  50 {
  51     m_pendingGCRunner = adoptPtr(new PendingGCRunner);
  52     m_thread->addTaskObserver(m_pendingGCRunner.get());
  53     ThreadState::attach();
  54     OwnPtr<MessageLoopInterruptor> interruptor = adoptPtr(new MessageLoopInterruptor(m_thread->taskRunner()));
  55     ThreadState::current()->addInterruptor(interruptor.release());
  56 }
  57
  58 void WebThreadSupportingGC::shutdown()
  59 {
  60     // Ensure no posted tasks will run from this point on.
  61     m_thread->removeTaskObserver(m_pendingGCRunner.get());
  62
  63     // Shutdown the thread (via its scheduler) only when the thread is created
  64     // and is owned by this instance.
  65     if (m_owningThread)
  66         m_owningThread->scheduler()->shutdown();
  67
  68     ThreadState::detach();
  69     m_pendingGCRunner = nullptr;
  70 }
  71
  72 } // namespace blink