thread.cc

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#ifdef POSIX
extern "C" {
#include <sys/time.h>
}
#endif

#include "common.h"
#include "logging.h"
#include "thread.h"
#include "time.h"

#define MSDEV_SET_THREAD_NAME  0x406D1388

namespace utils_base {

ThreadManager g_thmgr;

#ifdef POSIX
pthread_key_t ThreadManager::key_;

ThreadManager::ThreadManager() {
  pthread_key_create(&key_, NULL);
  main_thread_ = new Thread();
  SetCurrent(main_thread_);
}

ThreadManager::~ThreadManager() {
  pthread_key_delete(key_);
  delete main_thread_;
}

Thread *ThreadManager::CurrentThread() {
  return (Thread *)pthread_getspecific(key_);
}

void ThreadManager::SetCurrent(Thread *thread) {
  pthread_setspecific(key_, thread);
}
#endif

#ifdef WIN32
DWORD ThreadManager::key_;

ThreadManager::ThreadManager() {
  key_ = TlsAlloc();
  main_thread_ = new Thread();
  SetCurrent(main_thread_);
}

ThreadManager::~ThreadManager() {
  TlsFree(key_);
  delete main_thread_;
}

Thread *ThreadManager::CurrentThread() {
  return (Thread *)TlsGetValue(key_);
}

void ThreadManager::SetCurrent(Thread *thread) {
  TlsSetValue(key_, thread);
}
#endif

void ThreadManager::Add(Thread *thread) {
  CritScope cs(&crit_);
  threads_.push_back(thread);
}

void ThreadManager::Remove(Thread *thread) {
  CritScope cs(&crit_);
  threads_.erase(std::remove(threads_.begin(), threads_.end(), thread), threads_.end());
}

Thread::Thread(SocketServer* ss) : MessageQueue(ss), priority_(PRIORITY_NORMAL) {
  g_thmgr.Add(this);
  started_ = false;
  has_sends_ = false;
}

Thread::~Thread() {
  Stop();
  if (active_)
    Clear(NULL);
  g_thmgr.Remove(this);
}

#ifdef POSIX
void Thread::Start() {
  pthread_attr_t attr;
  pthread_attr_init(&attr);
  if (priority_ == PRIORITY_IDLE) {
    struct sched_param param;
    pthread_attr_getschedparam(&attr, &param);
    param.sched_priority = 15;           // +15 = 
    pthread_attr_setschedparam(&attr, &param);
  }
  pthread_create(&thread_, &attr, PreRun, this);
  started_ = true;
}

void Thread::Join() {
  if (started_) {
    void *pv;
    pthread_join(thread_, &pv);
  }
}
#endif

#ifdef WIN32

typedef struct tagTHREADNAME_INFO
{
  DWORD dwType;
  LPCSTR szName;
  DWORD dwThreadID;
  DWORD dwFlags;
} THREADNAME_INFO;

void SetThreadName( DWORD dwThreadID, LPCSTR szThreadName)
{
  THREADNAME_INFO info;
  {
    info.dwType = 0x1000;
    info.szName = szThreadName;
    info.dwThreadID = dwThreadID;
    info.dwFlags = 0;
  }
  __try
  {
    RaiseException(MSDEV_SET_THREAD_NAME, 0, sizeof(info)/sizeof(DWORD), (DWORD*)&info );
  }
  __except(EXCEPTION_CONTINUE_EXECUTION)
  {
  }
}

void Thread::Start() {
  DWORD flags = 0;
  if (priority_ != PRIORITY_NORMAL) {
    flags = CREATE_SUSPENDED;
  }
  thread_ = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)PreRun, this, flags, NULL);
  if (thread_) {
    if (priority_ != PRIORITY_NORMAL) {
       if (priority_ == PRIORITY_IDLE) {
         ::SetThreadPriority(thread_, THREAD_PRIORITY_IDLE);
       }
       ::ResumeThread(thread_);
    }
  }
  started_ = true;
}

void Thread::Join() {
  if (started_) {
    WaitForSingleObject(thread_, INFINITE);
    CloseHandle(thread_);
    started_ = false;
  }
}
#endif

void *Thread::PreRun(void *pv) {
  Thread *thread = (Thread *)pv;
  ThreadManager::SetCurrent(thread);
#if defined(WIN32) && defined(_DEBUG)
  char buf[256];
  _snprintf(buf, sizeof(buf), "Thread 0x%.8x", thread);
  SetThreadName(GetCurrentThreadId(), buf);
#endif
  thread->Run();
  return NULL;
}

void Thread::Run() {
  ProcessMessages(kForever);
}

void Thread::Stop() {
  MessageQueue::Stop();
  Join();
}

void Thread::Send(MessageHandler *phandler, uint32 id, MessageData *pdata) {
  if (fStop_)
    return;

  // Sent messages are sent to the MessageHandler directly, in the context
  // of "thread", like Win32 SendMessage. If in the right context,
  // call the handler directly.

  Message msg;
  msg.phandler = phandler;
  msg.message_id = id;
  msg.pdata = pdata;
  if (IsCurrent()) {
    phandler->OnMessage(&msg);
    return;
  }

  AutoThread thread; 
  Thread *current_thread = Thread::Current();
  ASSERT(current_thread != NULL);  // AutoThread ensures this

  bool ready = false;
  {
    CritScope cs(&crit_);
    EnsureActive();
    _SendMessage smsg;
    smsg.thread = current_thread;
    smsg.msg = msg;
    smsg.ready = &ready;
    sendlist_.push_back(smsg);
    has_sends_ = true;
  }

  // Wait for a reply

  ss_->WakeUp();

  bool waited = false;
  while (!ready) {
    current_thread->ReceiveSends();
    current_thread->socketserver()->Wait(kForever, false);
    waited = true;
  }

  // Our Wait loop above may have consumed some WakeUp events for this
  // MessageQueue, that weren't relevant to this Send.  Losing these WakeUps can
  // cause problems for some SocketServers.
  //
  // Concrete example:
  // Win32SocketServer on thread A calls Send on thread B.  While processing the
  // message, thread B Posts a message to A.  We consume the wakeup for that
  // Post while waiting for the Send to complete, which means that when we exit
  // this loop, we need to issue another WakeUp, or else the Posted message
  // won't be processed in a timely manner.

  if (waited) {
    current_thread->socketserver()->WakeUp();
  }
}

void Thread::ReceiveSends() {
  // Before entering critical section, check boolean.

  if (!has_sends_)
    return;

  // Receive a sent message. Cleanup scenarios:
  // - thread sending exits: We don't allow this, since thread can exit
  //   only via Join, so Send must complete.
  // - thread receiving exits: Wakeup/set ready in Thread::Clear()
  // - object target cleared: Wakeup/set ready in Thread::Clear()
  crit_.Enter();
  while (!sendlist_.empty()) {
    _SendMessage smsg = sendlist_.front();
    sendlist_.pop_front();
    crit_.Leave();
    smsg.msg.phandler->OnMessage(&smsg.msg);
    crit_.Enter();
    *smsg.ready = true;
    smsg.thread->socketserver()->WakeUp();
  }
  has_sends_ = false;
  crit_.Leave();
}

void Thread::Clear(MessageHandler *phandler, uint32 id) {
  CritScope cs(&crit_);

  // Remove messages on sendlist_ with phandler
  // Object target cleared: remove from send list, wakeup/set ready
  // if sender not NULL.

  std::list<_SendMessage>::iterator iter = sendlist_.begin();
  while (iter != sendlist_.end()) {
    _SendMessage smsg = *iter;
    if (phandler == NULL || smsg.msg.phandler == phandler) {
      if (id == (uint32)-1 || smsg.msg.message_id == id) {
        iter = sendlist_.erase(iter);
        *smsg.ready = true;
        smsg.thread->socketserver()->WakeUp();
        continue;
      }
    }
    ++iter;
  }

  MessageQueue::Clear(phandler, id);
}

bool Thread::ProcessMessages(int cmsLoop) {
  uint32 msEnd;
  if (cmsLoop != kForever)
    msEnd = GetMillisecondCount() + cmsLoop;
  int cmsNext = cmsLoop;

  while (true) {
    Message msg;
    if (!Get(&msg, cmsNext))
      return false;
    Dispatch(&msg);
    
    if (cmsLoop != kForever) {
      uint32 msCur = GetMillisecondCount();
      if (msCur >= msEnd)
        return true;
      cmsNext = msEnd - msCur;
    }
  }
}

AutoThread::AutoThread(SocketServer* ss) : Thread(ss) {
  if (!ThreadManager::CurrentThread()) {
    ThreadManager::SetCurrent(this);
  }
}

AutoThread::~AutoThread() {
  if (ThreadManager::CurrentThread() == this) {
    ThreadManager::SetCurrent(NULL);
  }
}

} // namespace talk_base