// excerpts from http://code.google.com/p/muduo/
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the License file.
 //
 // Author: Shuo Chen (chenshuo at chenshuo dot com)
 
 #include "EventLoop.h"
 
 #include "Channel.h"
 #include "Poller.h"
 #include "TimerQueue.h"
 
 #include "logging/Logging.h"
 
+#include <boost/bind.hpp>
+
 #include <assert.h>
+#include <sys/eventfd.h>
 
 using namespace muduo;
 
 __thread EventLoop* t_loopInThisThread = 0;
 const int kPollTimeMs = 10000;
 
+static int createEventfd()
+{
+  int evtfd = ::eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+  if (evtfd < 0)
+  {
+    LOG_SYSERR << "Failed in eventfd";
+    abort();
+  }
+  return evtfd;
+}
+
 EventLoop::EventLoop()
   : looping_(false),
     quit_(false),
+    callingPendingFunctors_(false),
     threadId_(CurrentThread::tid()),
     poller_(new Poller(this)),
     timerQueue_(new TimerQueue(this)),
+    wakeupFd_(createEventfd()),
+    wakeupChannel_(new Channel(this, wakeupFd_))
 {
   LOG_TRACE << "EventLoop created " << this << " in thread " << threadId_;
   if (t_loopInThisThread)
   {
     LOG_FATAL << "Another EventLoop " << t_loopInThisThread
               << " exists in this thread " << threadId_;
   }
   else
   {
     t_loopInThisThread = this;
   }
+  wakeupChannel_->setReadCallback(
+      boost::bind(&EventLoop::handleRead, this));
+  // we are always reading the wakeupfd
+  wakeupChannel_->enableReading();
 }
 
 EventLoop::~EventLoop()
 {
   assert(!looping_);
+  ::close(wakeupFd_);
   t_loopInThisThread = NULL;
 }
 
 void EventLoop::loop()
 {
   assert(!looping_);
   assertInLoopThread();
   looping_ = true;
   quit_ = false;
 
   while (!quit_)
   {
     activeChannels_.clear();
     pollReturnTime_ = poller_->poll(kPollTimeMs, &activeChannels_);
     for (ChannelList::iterator it = activeChannels_.begin();
         it != activeChannels_.end(); ++it)
     {
       (*it)->handleEvent();
     }
+    doPendingFunctors();
   }
 
   LOG_TRACE << "EventLoop " << this << " stop looping";
   looping_ = false;
 }
 
 void EventLoop::quit()
 {
   quit_ = true;
+  if (!isInLoopThread())
+  {
+    wakeup();
+  }
+}
+
+void EventLoop::runInLoop(const Functor& cb)
+{
+  if (isInLoopThread())
+  {
+    cb();
+  }
+  else
+  {
+    queueInLoop(cb);
+    wakeup();
+  }
+}
+
+void EventLoop::queueInLoop(const Functor& cb)
+{
+  {
+  MutexLockGuard lock(mutex_);
+  pendingFunctors_.push_back(cb);
+  }
+
+  if (isInLoopThread() && callingPendingFunctors_)
+  {
+    wakeup();
+  }
 }
 
 TimerId EventLoop::runAt(const Timestamp& time, const TimerCallback& cb)
 {
   return timerQueue_->addTimer(cb, time, 0.0);
 }
 
 TimerId EventLoop::runAfter(double delay, const TimerCallback& cb)
 {
   Timestamp time(addTime(Timestamp::now(), delay));
   return runAt(time, cb);
 }
 
 TimerId EventLoop::runEvery(double interval, const TimerCallback& cb)
 {
   Timestamp time(addTime(Timestamp::now(), interval));
   return timerQueue_->addTimer(cb, time, interval);
 }
 
 void EventLoop::updateChannel(Channel* channel)
 {
   assert(channel->ownerLoop() == this);
   assertInLoopThread();
   poller_->updateChannel(channel);
 }
 
 void EventLoop::abortNotInLoopThread()
 {
   LOG_FATAL << "EventLoop::abortNotInLoopThread - EventLoop " << this
             << " was created in threadId_ = " << threadId_
             << ", current thread id = " <<  CurrentThread::tid();
 }
 
+void EventLoop::wakeup()
+{
+  uint64_t one = 1;
+  ssize_t n = ::write(wakeupFd_, &one, sizeof one);
+  if (n != sizeof one)
+  {
+    LOG_ERROR << "EventLoop::wakeup() writes " << n << " bytes instead of 8";
+  }
+}
+
+void EventLoop::handleRead()
+{
+  uint64_t one = 1;
+  ssize_t n = ::read(wakeupFd_, &one, sizeof one);
+  if (n != sizeof one)
+  {
+    LOG_ERROR << "EventLoop::handleRead() reads " << n << " bytes instead of 8";
+  }
+}
+
+void EventLoop::doPendingFunctors()
+{
+  std::vector<Functor> functors;
+  callingPendingFunctors_ = true;
+
+  {
+  MutexLockGuard lock(mutex_);
+  functors.swap(pendingFunctors_);
+  }
+
+  for (size_t i = 0; i < functors.size(); ++i)
+  {
+    functors[i]();
+  }
+  callingPendingFunctors_ = false;
+}
+