reapack

commit 010c13e381ae264918bde2e4056c83cddcaa0534
parent 298b5b6a0744f982f45acaa3095040330408ce6e
Author: cfillion <cfillion@users.noreply.github.com>
Date:   Mon, 24 Sep 2018 23:11:28 -0400

modify the thread stop shared variable while the mutex is locked

https://stackoverflow.com/a/36130475/796375

Diffstat:
M
src/thread.cpp
 | 
28
++++++++++++++++++++--------
M
src/thread.hpp
 | 
3
+--

2 files changed, 21 insertions(+), 10 deletions(-)
diff --git a/src/thread.cpp b/src/thread.cpp
@@ -88,26 +88,38 @@ void ThreadTask::exec()
   ThreadNotifier::get()->notify({this, state});
 };
 
-WorkerThread::WorkerThread() : m_exit(false), m_thread(&WorkerThread::run, this)
+WorkerThread::WorkerThread() : m_stop(false), m_thread(&WorkerThread::run, this)
 {
 }
 
 WorkerThread::~WorkerThread()
 {
-  m_exit = true;
+  {
+    std::lock_guard lock(m_mutex);
+    m_stop = true;
+  }
+
   m_wake.notify_one();
   m_thread.join();
 }
 
 void WorkerThread::run()
 {
-  do {
-    while(ThreadTask *task = nextTask())
-      task->exec();
+  unique_lock<mutex> lock(m_mutex);
+
+  while(true) {
+    m_wake.wait(lock, [=] { return !m_queue.empty() || m_stop; });
+
+    if(m_stop)
+      break;
 
-    unique_lock<mutex> lock(m_mutex);
-    m_wake.wait(lock);
-  } while(!m_exit);
+    ThreadTask *task = m_queue.front();
+    m_queue.pop();
+
+    lock.unlock();
+    task->exec();
+    lock.lock();
+  }
 
 #ifdef _WIN32
   // HACK: Destruct thread-local storage objects earlier on Windows to avoid a
diff --git a/src/thread.hpp b/src/thread.hpp
@@ -21,7 +21,6 @@
 #include "errors.hpp"
 
 #include <array>
-#include <atomic>
 #include <condition_variable>
 #include <functional>
 #include <queue>
@@ -89,8 +88,8 @@ private:
   void run();
   ThreadTask *nextTask();
 
+  bool m_stop;
   std::mutex m_mutex;
-  std::atomic_bool m_exit;
   std::condition_variable m_wake;
   std::queue<ThreadTask *> m_queue;