event/Loop: use std::lock_guard

src/event/Loop.cxx

@@ -181,17 +181,17 @@ EventLoop::Run()
 
 		/* try to handle DeferredMonitors without WakeFD
 		   overhead */
-		mutex.lock();
+		{
+			const std::lock_guard<Mutex> lock(mutex);
 			HandleDeferred();
 			busy = false;
-		const bool _again = again;
-		mutex.unlock();
 
-		if (_again)
-			/* re-evaluate timers because one of the
-			   IdleMonitors may have added a new
-			   timeout */
+			if (again)
+				/* re-evaluate timers because one of
+				   the IdleMonitors may have added a
+				   new timeout */
 				continue;
+		}
 
 		/* wait for new event */
 
@@ -199,9 +199,10 @@ EventLoop::Run()
 
 		now = std::chrono::steady_clock::now();
 
-		mutex.lock();
+		{
+			const std::lock_guard<Mutex> lock(mutex);
 			busy = true;
-		mutex.unlock();
+		}
 
 		/* invoke sockets */
 		for (int i = 0; i < poll_result.GetSize(); ++i) {
@@ -230,23 +231,24 @@ EventLoop::Run()
 void
 EventLoop::AddDeferred(DeferredMonitor &d)
 {
-	mutex.lock();
-	if (d.pending) {
-		mutex.unlock();
+	bool must_wake;
+
+	{
+		const std::lock_guard<Mutex> lock(mutex);
+		if (d.pending)
 			return;
-	}
 
 		assert(std::find(deferred.begin(),
 				 deferred.end(), &d) == deferred.end());
 
 		/* we don't need to wake up the EventLoop if another
 		   DeferredMonitor has already done it */
-	const bool must_wake = !busy && deferred.empty();
+		must_wake = !busy && deferred.empty();
 
 		d.pending = true;
 		deferred.push_back(&d);
 		again = true;
-	mutex.unlock();
+	}
 
 	if (must_wake)
 		wake_fd.Write();
@@ -281,9 +283,8 @@ EventLoop::HandleDeferred()
 		deferred.pop_front();
 		m.pending = false;
 
-		mutex.unlock();
+		const ScopeUnlock unlock(mutex);
 		m.RunDeferred();
-		mutex.lock();
 	}
 }
 
@@ -294,9 +295,8 @@ EventLoop::OnSocketReady(gcc_unused unsigned flags)
 
 	wake_fd.Read();
 
-	mutex.lock();
+	const std::lock_guard<Mutex> lock(mutex);
 	HandleDeferred();
-	mutex.unlock();
 
 	return true;
 }