PlatformThreadHandle: remove public id() interface

base/threading/thread.cc

 // Copyright (c) 2012 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/threading/thread.h"
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/location.h"
 #include "base/synchronization/waitable_event.h"
@@ skipping 44 matching lines @@
 }
 
 Thread::Thread(const std::string& name)
     :
 #if defined(OS_WIN)
       com_status_(NONE),
 #endif
       stopping_(false),
       running_(false),
       thread_(0),
+      id_(kInvalidThreadId),
       message_loop_(nullptr),
       message_loop_timer_slack_(TIMER_SLACK_NONE),
       name_(name) {
 }
 
 Thread::~Thread() {
   Stop();
 }
 
 bool Thread::Start() {
@@ skipping 95 matching lines @@
   DCHECK_NE(thread_id(), PlatformThread::CurrentId());
 
   if (stopping_ || !message_loop_)
     return;
 
   stopping_ = true;
   task_runner()->PostTask(FROM_HERE, base::Bind(&ThreadQuitHelper));
 }
 
 PlatformThreadId Thread::thread_id() const {
-  AutoLock lock(thread_lock_);
-  return thread_.id();
+  CHECK_NE(kInvalidThreadId, id_);

[gab, 2015/07/09 18:19:00]

Is this really a security issue? i.e. is it worth forcing a crash right here in
official builds?

Ref:
https://www.chromium.org/developers/coding-style#TOC-CHECK-DCHECK-and-NOTREAC...

[Takashi Toyoshima, 2015/07/14 10:47:28]

I see, DCHECK_NE looks better here.

+  AutoLock lock(id_lock_);
+  return id_;
 }
 
 bool Thread::IsRunning() const {
   // If the thread's already started (i.e. message_loop_ is non-null) and
   // not yet requested to stop (i.e. stopping_ is false) we can just return
   // true. (Note that stopping_ is touched only on the same thread that
   // starts / started the new thread so we need no locking here.)
   if (message_loop_ && !stopping_)
     return true;
   // Otherwise check the running_ flag, which is set to true by the new thread
@@ skipping 13 matching lines @@
 bool Thread::GetThreadWasQuitProperly() {
   bool quit_properly = true;
 #ifndef NDEBUG
   quit_properly = lazy_tls_bool.Pointer()->Get();
 #endif
   return quit_properly;
 }
 
 void Thread::ThreadMain() {
   // Complete the initialization of our Thread object.
+  {
+    AutoLock lock(id_lock_);
+    id_ = PlatformThread::CurrentId();
+  }
   PlatformThread::SetName(name_.c_str());
   ANNOTATE_THREAD_NAME(name_.c_str());  // Tell the name to race detector.
 
   // Lazily initialize the message_loop so that it can run on this thread.
   DCHECK(message_loop_);
   scoped_ptr<MessageLoop> message_loop(message_loop_);
   message_loop_->BindToCurrentThread();
   message_loop_->set_thread_name(name_);
   message_loop_->SetTimerSlack(message_loop_timer_slack_);
 
 #if defined(OS_WIN)
   scoped_ptr<win::ScopedCOMInitializer> com_initializer;
   if (com_status_ != NONE) {
     com_initializer.reset((com_status_ == STA) ?
         new win::ScopedCOMInitializer() :
         new win::ScopedCOMInitializer(win::ScopedCOMInitializer::kMTA));
   }
 #endif
 
-  // Make sure the thread_id() returns current thread.
-  // (This internally acquires lock against PlatformThread::Create)
-  DCHECK_EQ(thread_id(), PlatformThread::CurrentId());
-
   // Let the thread do extra initialization.
   Init();
 
   {
     AutoLock lock(running_lock_);
     running_ = true;
   }
 
   start_event_->Signal();
 
@@ skipping 13 matching lines @@
 
   // Assert that MessageLoop::Quit was called by ThreadQuitHelper.
   DCHECK(GetThreadWasQuitProperly());
 
   // We can't receive messages anymore.
   // (The message loop is destructed at the end of this block)
   message_loop_ = NULL;
 }
 
 }  // namespace base