PlatformThreadHandle: remove public id() interface

base/threading/thread.cc

Index: base/threading/thread.cc
diff --git a/base/threading/thread.cc b/base/threading/thread.cc
index 7bff24232e2bf2d66fda4485a4246ebae2e98332..ad229f6f3e31a8908c3d3ff317706c8b10d9f733 100644
--- a/base/threading/thread.cc
+++ b/base/threading/thread.cc
@@ -62,6 +62,7 @@ Thread::Thread(const std::string& name)
       stopping_(false),
       running_(false),
       thread_(0),
+      id_(kInvalidThreadId),
       message_loop_(nullptr),
       message_loop_timer_slack_(TIMER_SLACK_NONE),
       name_(name) {
@@ -97,25 +98,14 @@ bool Thread::StartWithOptions(const Options& options) {
   scoped_ptr<MessageLoop> message_loop = MessageLoop::CreateUnbound(
       type, options.message_pump_factory);
   message_loop_ = message_loop.get();
-  start_event_.reset(new WaitableEvent(false, false));
+  start_event_.reset(new WaitableEvent(true, false));
 
-  // Hold the thread_lock_ while starting a new thread, so that we can make sure
-  // that thread_ is populated before the newly created thread accesses it.
-  {
-    AutoLock lock(thread_lock_);
-    bool created;
-    if (options.priority == ThreadPriority::NORMAL) {
-      created = PlatformThread::Create(options.stack_size, this, &thread_);
-    } else {
-      created = PlatformThread::CreateWithPriority(options.stack_size, this,
-                                                   &thread_, options.priority);
-    }
-    if (!created) {
-      DLOG(ERROR) << "failed to create thread";
-      message_loop_ = nullptr;
-      start_event_.reset();
-      return false;
-    }
+  if (!PlatformThread::CreateWithPriority(options.stack_size, this,
+                                          &thread_, options.priority)) {
+    DLOG(ERROR) << "failed to create thread";
+    message_loop_ = nullptr;
+    start_event_.reset();
+    return false;
   }
 
   // The ownership of message_loop is managemed by the newly created thread
@@ -165,20 +155,23 @@ void Thread::Stop() {
 }
 
 void Thread::StopSoon() {
-  // We should only be called on the same thread that started us.
-
-  DCHECK_NE(thread_id(), PlatformThread::CurrentId());
-
   if (stopping_ || !message_loop_)
     return;
 
+  // Wait for the thread starts running to call thread_id().
+  WaitUntilThreadStarted();
+
+  // We should only be called on the same thread that started us.
+  DCHECK_NE(thread_id(), PlatformThread::CurrentId());
+
   stopping_ = true;
   task_runner()->PostTask(FROM_HERE, base::Bind(&ThreadQuitHelper));
 }
 
 PlatformThreadId Thread::thread_id() const {
-  AutoLock lock(thread_lock_);
-  return thread_.id();
+  AutoLock lock(lock_);
+  DCHECK_NE(kInvalidThreadId, id_);

[kinuko, 2015/07/16 00:50:36]

Assume that we could fix all the failing tests, how we could make sure this
change doesn't introduce flaky failure on production code?

[Takashi Toyoshima, 2015/07/16 05:07:31]

Thanks. I'm doing trial and error here
https://codereview.chromium.org/1239623003/
This was one big reason of test failures, and I will change this to call
WaitUntilThreadStarted() here.
Once I get a good try result, I'll update patch set here.

+  return id_;
 }
 
 bool Thread::IsRunning() const {
@@ -190,7 +183,7 @@ bool Thread::IsRunning() const {
     return true;
   // Otherwise check the running_ flag, which is set to true by the new thread
   // only while it is inside Run().
-  AutoLock lock(running_lock_);
+  AutoLock lock(lock_);
   return running_;
 }
 
@@ -212,6 +205,10 @@ bool Thread::GetThreadWasQuitProperly() {
 
 void Thread::ThreadMain() {
   // Complete the initialization of our Thread object.
+  {
+    AutoLock lock(lock_);
+    id_ = PlatformThread::CurrentId();
+  }
   PlatformThread::SetName(name_.c_str());
   ANNOTATE_THREAD_NAME(name_.c_str());  // Tell the name to race detector.
 
@@ -231,15 +228,11 @@ void Thread::ThreadMain() {
   }
 #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_);
+    AutoLock lock(lock_);
     running_ = true;
   }
 
@@ -248,7 +241,7 @@ void Thread::ThreadMain() {
   Run(message_loop_);
 
   {
-    AutoLock lock(running_lock_);
+    AutoLock lock(lock_);
     running_ = false;
   }