Move a bunch of code from the old to new TLS interface.

base/message_loop.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/message_loop.h"
 
 #include <algorithm>
 
 #include "base/compiler_specific.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/message_pump_default.h"
 #include "base/string_util.h"
-#include "base/thread_local_storage.h"
+#include "base/thread_local.h"
 
-// a TLS index to the message loop for the current thread
-// Note that if we start doing complex stuff in other static initializers
-// this could cause problems.
-// TODO(evanm): this shouldn't rely on static initialization.
-// static
-TLSSlot MessageLoop::tls_index_;
+// A lazily created thread local storage for quick access to a thread's message
+// loop, if one exists.  This should be safe and free of static constructors.
+static base::LazyInstance<base::ThreadLocalPointer<MessageLoop> > lazy_tls_ptr(
+    base::LINKER_INITIALIZED);
 
 //------------------------------------------------------------------------------
 
 // Logical events for Histogram profiling. Run with -message-loop-histogrammer
 // to get an accounting of messages and actions taken on each thread.
 static const int kTaskRunEvent = 0x1;
 static const int kTimerEvent = 0x2;
 
 // Provide range of message IDs for use in histogramming and debug display.
 static const int kLeastNonZeroMessageId = 1;
@@ skipping 17 matching lines @@
   LPTOP_LEVEL_EXCEPTION_FILTER top_filter = NULL;
   top_filter = ::SetUnhandledExceptionFilter(0);
   ::SetUnhandledExceptionFilter(top_filter);
   return top_filter;
 }
 
 #endif  // defined(OS_WIN)
 
 //------------------------------------------------------------------------------
 
+// static
+MessageLoop* MessageLoop::current() {
+  // TODO(darin): sadly, we cannot enable this yet since people call us even
+  // when they have no intention of using us.
+  //DCHECK(loop) << "Ouch, did you forget to initialize me?";
+  return lazy_tls_ptr.Pointer()->Get();
+}
+
 MessageLoop::MessageLoop(Type type)
     : type_(type),
       nestable_tasks_allowed_(true),
       exception_restoration_(false),
       state_(NULL),
       next_sequence_num_(0) {
-  DCHECK(!tls_index_.Get()) << "should only have one message loop per thread";
-  tls_index_.Set(this);
+  DCHECK(!current()) << "should only have one message loop per thread";
+  lazy_tls_ptr.Pointer()->Set(this);
 
   // TODO(darin): Choose the pump based on the requested type.
 #if defined(OS_WIN)
   if (type_ == TYPE_DEFAULT) {
     pump_ = new base::MessagePumpDefault();
   } else {
     pump_ = new base::MessagePumpWin();
   }
 #else
   pump_ = new base::MessagePumpDefault();
 #endif
 }
 
 MessageLoop::~MessageLoop() {
   DCHECK(this == current());
 
   // Let interested parties have one last shot at accessing this.
   FOR_EACH_OBSERVER(DestructionObserver, destruction_observers_,
                     WillDestroyCurrentMessageLoop());
 
   // OK, now make it so that no one can find us.
-  tls_index_.Set(NULL);
+  lazy_tls_ptr.Pointer()->Set(NULL);
 
   DCHECK(!state_);
 
   // Most tasks that have not been Run() are deleted in the |timer_manager_|
   // destructor after we remove our tls index.  We delete the tasks in our
   // queues here so their destuction is similar to the tasks in the
   // |timer_manager_|.
   DeletePendingTasks();
   ReloadWorkQueue();
   DeletePendingTasks();
@@ skipping 430 matching lines @@
 //------------------------------------------------------------------------------
 // MessageLoopForIO
 
 #if defined(OS_WIN)
 
 void MessageLoopForIO::WatchObject(HANDLE object, Watcher* watcher) {
   pump_win()->WatchObject(object, watcher);
 }
 
 #endif  // defined(OS_WIN)