michael@0: // Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "base/thread.h"
michael@0: 
michael@0: #include "base/lazy_instance.h"
michael@0: #include "base/string_util.h"
michael@0: #include "base/thread_local.h"
michael@0: #include "base/waitable_event.h"
michael@0: #include "GeckoProfiler.h"
michael@0: #include "mozilla/IOInterposer.h"
michael@0: 
michael@0: #ifdef MOZ_TASK_TRACER
michael@0: #include "GeckoTaskTracer.h"
michael@0: #endif
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: // This task is used to trigger the message loop to exit.
michael@0: class ThreadQuitTask : public Task {
michael@0:  public:
michael@0:   virtual void Run() {
michael@0:     MessageLoop::current()->Quit();
michael@0:     Thread::SetThreadWasQuitProperly(true);
michael@0:   }
michael@0: };
michael@0: 
michael@0: // Used to pass data to ThreadMain.  This structure is allocated on the stack
michael@0: // from within StartWithOptions.
michael@0: struct Thread::StartupData {
michael@0:   // We get away with a const reference here because of how we are allocated.
michael@0:   const Thread::Options& options;
michael@0: 
michael@0:   // Used to synchronize thread startup.
michael@0:   WaitableEvent event;
michael@0: 
michael@0:   explicit StartupData(const Options& opt)
michael@0:       : options(opt),
michael@0:         event(false, false) {}
michael@0: };
michael@0: 
michael@0: Thread::Thread(const char *name)
michael@0:     : startup_data_(NULL),
michael@0:       thread_(0),
michael@0:       message_loop_(NULL),
michael@0:       thread_id_(0),
michael@0:       name_(name) {
michael@0: }
michael@0: 
michael@0: Thread::~Thread() {
michael@0:   Stop();
michael@0: }
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: // We use this thread-local variable to record whether or not a thread exited
michael@0: // because its Stop method was called.  This allows us to catch cases where
michael@0: // MessageLoop::Quit() is called directly, which is unexpected when using a
michael@0: // Thread to setup and run a MessageLoop.
michael@0: base::LazyInstance<base::ThreadLocalBoolean> lazy_tls_bool(
michael@0:     base::LINKER_INITIALIZED);
michael@0: 
michael@0: }  // namespace
michael@0: 
michael@0: void Thread::SetThreadWasQuitProperly(bool flag) {
michael@0:   lazy_tls_bool.Pointer()->Set(flag);
michael@0: }
michael@0: 
michael@0: bool Thread::GetThreadWasQuitProperly() {
michael@0:   bool quit_properly = true;
michael@0: #ifndef NDEBUG
michael@0:   quit_properly = lazy_tls_bool.Pointer()->Get();
michael@0: #endif
michael@0:   return quit_properly;
michael@0: }
michael@0: 
michael@0: bool Thread::Start() {
michael@0:   return StartWithOptions(Options());
michael@0: }
michael@0: 
michael@0: bool Thread::StartWithOptions(const Options& options) {
michael@0:   DCHECK(!message_loop_);
michael@0: 
michael@0:   SetThreadWasQuitProperly(false);
michael@0: 
michael@0:   StartupData startup_data(options);
michael@0:   startup_data_ = &startup_data;
michael@0: 
michael@0:   if (!PlatformThread::Create(options.stack_size, this, &thread_)) {
michael@0:     DLOG(ERROR) << "failed to create thread";
michael@0:     startup_data_ = NULL;  // Record that we failed to start.
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   // Wait for the thread to start and initialize message_loop_
michael@0:   startup_data.event.Wait();
michael@0: 
michael@0:   DCHECK(message_loop_);
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: void Thread::Stop() {
michael@0:   if (!thread_was_started())
michael@0:     return;
michael@0: 
michael@0:   // We should only be called on the same thread that started us.
michael@0:   DCHECK_NE(thread_id_, PlatformThread::CurrentId());
michael@0: 
michael@0:   // StopSoon may have already been called.
michael@0:   if (message_loop_)
michael@0:     message_loop_->PostTask(FROM_HERE, new ThreadQuitTask());
michael@0: 
michael@0:   // Wait for the thread to exit.  It should already have terminated but make
michael@0:   // sure this assumption is valid.
michael@0:   //
michael@0:   // TODO(darin): Unfortunately, we need to keep message_loop_ around until
michael@0:   // the thread exits.  Some consumers are abusing the API.  Make them stop.
michael@0:   //
michael@0:   PlatformThread::Join(thread_);
michael@0: 
michael@0:   // The thread can't receive messages anymore.
michael@0:   message_loop_ = NULL;
michael@0: 
michael@0:   // The thread no longer needs to be joined.
michael@0:   startup_data_ = NULL;
michael@0: }
michael@0: 
michael@0: void Thread::StopSoon() {
michael@0:   if (!message_loop_)
michael@0:     return;
michael@0: 
michael@0:   // We should only be called on the same thread that started us.
michael@0:   DCHECK_NE(thread_id_, PlatformThread::CurrentId());
michael@0: 
michael@0:   // We had better have a message loop at this point!  If we do not, then it
michael@0:   // most likely means that the thread terminated unexpectedly, probably due
michael@0:   // to someone calling Quit() on our message loop directly.
michael@0:   DCHECK(message_loop_);
michael@0: 
michael@0:   message_loop_->PostTask(FROM_HERE, new ThreadQuitTask());
michael@0: }
michael@0: 
michael@0: void Thread::ThreadMain() {
michael@0:   char aLocal;
michael@0:   profiler_register_thread(name_.c_str(), &aLocal);
michael@0:   mozilla::IOInterposer::RegisterCurrentThread();
michael@0: 
michael@0:   // The message loop for this thread.
michael@0:   MessageLoop message_loop(startup_data_->options.message_loop_type);
michael@0: 
michael@0:   // Complete the initialization of our Thread object.
michael@0:   thread_id_ = PlatformThread::CurrentId();
michael@0:   PlatformThread::SetName(name_.c_str());
michael@0:   message_loop.set_thread_name(name_);
michael@0:   message_loop.set_hang_timeouts(startup_data_->options.transient_hang_timeout,
michael@0:                                  startup_data_->options.permanent_hang_timeout);
michael@0:   message_loop_ = &message_loop;
michael@0: 
michael@0:   // Let the thread do extra initialization.
michael@0:   // Let's do this before signaling we are started.
michael@0:   Init();
michael@0: 
michael@0:   startup_data_->event.Signal();
michael@0:   // startup_data_ can't be touched anymore since the starting thread is now
michael@0:   // unlocked.
michael@0: 
michael@0:   message_loop.Run();
michael@0: 
michael@0:   // Let the thread do extra cleanup.
michael@0:   CleanUp();
michael@0: 
michael@0:   // Assert that MessageLoop::Quit was called by ThreadQuitTask.
michael@0:   DCHECK(GetThreadWasQuitProperly());
michael@0: 
michael@0:   mozilla::IOInterposer::UnregisterCurrentThread();
michael@0:   profiler_unregister_thread();
michael@0: 
michael@0: #ifdef MOZ_TASK_TRACER
michael@0:   mozilla::tasktracer::FreeTraceInfo();
michael@0: #endif
michael@0: 
michael@0:   // We can't receive messages anymore.
michael@0:   message_loop_ = NULL;
michael@0:   thread_id_ = 0;
michael@0: }
michael@0: 
michael@0: }  // namespace base