From 40bc7779aa7caa0ecac413d768b89a9315fb87f1 Mon Sep 17 00:00:00 2001
From: "fischman@webrtc.org"
 <fischman@webrtc.org@4adac7df-926f-26a2-2b94-8c16560cd09d>
Date: Mon, 19 May 2014 17:58:04 +0000
Subject: [PATCH] talk_base: remove lock inversion between MessageQueue and
 MessageQueueManager.

Removes the concept of a MessageQueue being "active" in favor of considering all
live MQ's to be active.
(previously a MQ was active starting from the first Post to it and stopped being
active in its dtor).

BUG=3230
R=sriniv@google.com

Review URL: https://webrtc-codereview.appspot.com/21489004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6190 4adac7df-926f-26a2-2b94-8c16560cd09d
---
 talk/base/messagequeue.cc | 19 ++++---------------
 talk/base/messagequeue.h  |  6 +-----
 talk/base/thread.cc       |  4 +---
 3 files changed, 6 insertions(+), 23 deletions(-)

diff --git a/talk/base/messagequeue.cc b/talk/base/messagequeue.cc
index 64e63ae3dc..7bda92411c 100644
--- a/talk/base/messagequeue.cc
+++ b/talk/base/messagequeue.cc
@@ -126,7 +126,7 @@ void MessageQueueManager::ClearInternal(MessageHandler *handler) {
 // MessageQueue
 
 MessageQueue::MessageQueue(SocketServer* ss)
-    : ss_(ss), fStop_(false), fPeekKeep_(false), active_(false),
+    : ss_(ss), fStop_(false), fPeekKeep_(false),
       dmsgq_next_num_(0) {
   if (!ss_) {
     // Currently, MessageQueue holds a socket server, and is the base class for
@@ -138,6 +138,7 @@ MessageQueue::MessageQueue(SocketServer* ss)
     ss_ = default_ss_.get();
   }
   ss_->SetMessageQueue(this);
+  MessageQueueManager::Add(this);
 }
 
 MessageQueue::~MessageQueue() {
@@ -145,10 +146,8 @@ MessageQueue::~MessageQueue() {
   // that it always gets called when the queue
   // is going away.
   SignalQueueDestroyed();
-  if (active_) {
-    MessageQueueManager::Remove(this);
-    Clear(NULL);
-  }
+  MessageQueueManager::Remove(this);
+  Clear(NULL);
   if (ss_) {
     ss_->SetMessageQueue(NULL);
   }
@@ -296,7 +295,6 @@ void MessageQueue::Post(MessageHandler *phandler, uint32 id,
   // Signal for the multiplexer to return
 
   CritScope cs(&crit_);
-  EnsureActive();
   Message msg;
   msg.phandler = phandler;
   msg.message_id = id;
@@ -318,7 +316,6 @@ void MessageQueue::DoDelayPost(int cmsDelay, uint32 tstamp,
   // Signal for the multiplexer to return.
 
   CritScope cs(&crit_);
-  EnsureActive();
   Message msg;
   msg.phandler = phandler;
   msg.message_id = id;
@@ -401,12 +398,4 @@ void MessageQueue::Dispatch(Message *pmsg) {
   pmsg->phandler->OnMessage(pmsg);
 }
 
-void MessageQueue::EnsureActive() {
-  ASSERT(crit_.CurrentThreadIsOwner());
-  if (!active_) {
-    active_ = true;
-    MessageQueueManager::Add(this);
-  }
-}
-
 }  // namespace talk_base
diff --git a/talk/base/messagequeue.h b/talk/base/messagequeue.h
index fc72166e4b..dc2b5a89a5 100644
--- a/talk/base/messagequeue.h
+++ b/talk/base/messagequeue.h
@@ -75,7 +75,7 @@ class MessageQueueManager {
   void ClearInternal(MessageHandler *handler);
 
   static MessageQueueManager* instance_;
-  // This list contains 'active' MessageQueues.
+  // This list contains all live MessageQueues.
   std::vector<MessageQueue *> message_queues_;
   CriticalSection crit_;
 };
@@ -247,7 +247,6 @@ class MessageQueue {
     void reheap() { make_heap(c.begin(), c.end(), comp); }
   };
 
-  void EnsureActive();
   void DoDelayPost(int cmsDelay, uint32 tstamp, MessageHandler *phandler,
                    uint32 id, MessageData* pdata);
 
@@ -258,9 +257,6 @@ class MessageQueue {
   bool fStop_;
   bool fPeekKeep_;
   Message msgPeek_;
-  // A message queue is active if it has ever had a message posted to it.
-  // This also corresponds to being in MessageQueueManager's global list.
-  bool active_;
   MessageList msgq_;
   PriorityQueue dmsgq_;
   uint32 dmsgq_next_num_;
diff --git a/talk/base/thread.cc b/talk/base/thread.cc
index d4cebc4d55..3fd1ca4bba 100644
--- a/talk/base/thread.cc
+++ b/talk/base/thread.cc
@@ -157,8 +157,7 @@ Thread::Thread(SocketServer* ss)
 
 Thread::~Thread() {
   Stop();
-  if (active_)
-    Clear(NULL);
+  Clear(NULL);
 }
 
 bool Thread::SleepMs(int milliseconds) {
@@ -403,7 +402,6 @@ void Thread::Send(MessageHandler *phandler, uint32 id, MessageData *pdata) {
   bool ready = false;
   {
     CritScope cs(&crit_);
-    EnsureActive();
     _SendMessage smsg;
     smsg.thread = current_thread;
     smsg.msg = msg;