Thread pool changes

runtime/bin/thread_pool_macos.cc

Index: runtime/bin/thread_pool_macos.cc
diff --git a/runtime/bin/thread_pool_macos.cc b/runtime/bin/thread_pool_macos.cc
index 962bb0bfbd23264b05a6f0c93cea220bab79a480..f0e37342d5c2d0d4c1adac680efdb9e121453fae 100644
--- a/runtime/bin/thread_pool_macos.cc
+++ b/runtime/bin/thread_pool_macos.cc
@@ -6,7 +6,7 @@
 
 #include "bin/thread_pool.h"
 
-TaskQueue::TaskQueue() : head_(NULL), tail_(NULL) {
+TaskQueue::TaskQueue() : terminate_(false), head_(NULL), tail_(NULL) {
   int result;
 
   result = pthread_mutex_init(data_.mutex(), NULL);
@@ -39,7 +39,15 @@ TaskQueueEntry* TaskQueue::Remove() {
   pthread_mutex_lock(data_.mutex());
   TaskQueueEntry* result = head_;
   while (result == NULL) {
+    if (terminate_) {
+      pthread_mutex_unlock(data_.mutex());
+      return NULL;
+    }
     pthread_cond_wait(data_.cond(), data_.mutex());
+    if (terminate_) {
+      pthread_mutex_unlock(data_.mutex());
+      return NULL;
+    }
     result = head_;
   }
   head_ = result->next();
@@ -49,9 +57,17 @@ TaskQueueEntry* TaskQueue::Remove() {
 }
 
 
+void TaskQueue::Shutdown() {
+  pthread_mutex_lock(data_.mutex());
+  terminate_ = true;
+  pthread_cond_broadcast(data_.cond());
+  pthread_mutex_unlock(data_.mutex());
+}
+
+
 void ThreadPool::Start() {
   pthread_t* threads
-      = reinterpret_cast<pthread_t*>(calloc(size_, sizeof(pthread_t*)));
+      = reinterpret_cast<pthread_t*>(calloc(size_, sizeof(pthread_t*)));  // NOLINT
   data_.set_threads(threads);
   for (int i = 0; i < size_; i++) {
     pthread_t handler_thread;
@@ -65,3 +81,12 @@ void ThreadPool::Start() {
     data_.threads()[i] = handler_thread;
   }
 }
+
+
+void ThreadPool::Shutdown() {
+  terminate_ = true;
+  queue_.Shutdown();
+  for (int i = 0; i < size_; i++) {
+    pthread_join(data_.threads()[i], NULL);
+  }
+}