IdleMonitor: new class to replace GlobalEvents::IDLE

Use MaskMonitor to eliminate duplicate code.

Makefile.am

@@ -95,6 +95,7 @@ libmpd_a_SOURCES = \
 	src/command/OtherCommands.cxx src/command/OtherCommands.hxx \
 	src/command/CommandListBuilder.cxx src/command/CommandListBuilder.hxx \
 	src/Idle.cxx src/Idle.hxx \
+	src/IdleMaskMonitor.hxx \
 	src/IdleFlags.cxx src/IdleFlags.hxx \
 	src/decoder/DecoderError.cxx src/decoder/DecoderError.hxx \
 	src/decoder/DecoderThread.cxx src/decoder/DecoderThread.hxx \

src/GlobalEvents.hxx

@@ -24,9 +24,6 @@
 
 namespace GlobalEvents {
 	enum Event {
-		/** an idle event was emitted */
-		IDLE,
-
 		/** must call playlist_sync() */
 		PLAYLIST,
 

src/Idle.cxx

@@ -27,25 +27,12 @@
 #include "Main.hxx"
 #include "Instance.hxx"
 
-#include <atomic>
-
 #include <assert.h>
 
-static std::atomic_uint idle_flags;
-
 void
 idle_add(unsigned flags)
 {
 	assert(flags != 0);
 
-	unsigned old_flags = idle_flags.fetch_or(flags);
-
-	if ((old_flags & flags) != flags)
-		instance->global_events.Emit(GlobalEvents::IDLE);
-}
-
-unsigned
-idle_get(void)
-{
-	return idle_flags.exchange(0);
+	instance->EmitIdle(flags);
 }

src/Idle.hxx

@@ -34,10 +34,4 @@
 void
 idle_add(unsigned flags);
 
-/**
- * Atomically reads and resets the global idle flags value.
- */
-unsigned
-idle_get();
-
 #endif

src/IdleMaskMonitor.hxx

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2003-2016 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_IDLE_MONITOR_HXX
+#define MPD_IDLE_MONITOR_HXX
+
+#include "event/MaskMonitor.hxx"
+
+class IdleMaskMonitor : MaskMonitor {
+public:
+	explicit IdleMaskMonitor(EventLoop &_loop)
+		:MaskMonitor(_loop) {}
+
+	void EmitIdle(unsigned mask) {
+		OrMask(mask);
+	}
+
+protected:
+	virtual void OnIdle(unsigned mask) = 0;
+
+private:
+	/* virtual methods from class MaskMonitor */
+	void HandleMask(unsigned mask) final {
+		OnIdle(mask);
+	}
+};
+
+#endif

src/Instance.hxx

@@ -22,6 +22,7 @@
 
 #include "check.h"
 #include "event/Loop.hxx"
+#include "IdleMaskMonitor.hxx"
 #include "GlobalEvents.hxx"
 #include "Compiler.h"
 
@@ -51,7 +52,8 @@ struct EventLoopHolder {
 };
 
 struct Instance final
-	: EventLoopHolder
+	: EventLoopHolder,
+	  IdleMaskMonitor
 #if defined(ENABLE_DATABASE) || defined(ENABLE_NEIGHBOR_PLUGINS)
 	,
 #endif
@@ -89,7 +91,9 @@ struct Instance final
 
 	StateFile *state_file;
 
-	Instance():global_events(event_loop) {}
+	Instance()
+		:IdleMaskMonitor(event_loop),
+		 global_events(event_loop) {}
 
 	/**
 	 * Initiate shutdown.  Wrapper for EventLoop::Break().
@@ -129,6 +133,9 @@ private:
 	virtual void FoundNeighbor(const NeighborInfo &info) override;
 	virtual void LostNeighbor(const NeighborInfo &info) override;
 #endif
+
+	/* virtual methods from class IdleMaskMonitor */
+	void OnIdle(unsigned mask) override;
 };
 
 #endif

src/Main.cxx

@@ -365,21 +365,16 @@ initialize_decoder_and_player(void)
 					    buffered_before_play);
 }
 
-/**
- * Handler for GlobalEvents::IDLE.
- */
-static void
-idle_event_emitted(void)
+void
+Instance::OnIdle(unsigned flags)
 {
 	/* send "idle" notifications to all subscribed
 	   clients */
-	unsigned flags = idle_get();
-	if (flags != 0)
-		instance->client_list->IdleAdd(flags);
+	client_list->IdleAdd(flags);
 
 	if (flags & (IDLE_PLAYLIST|IDLE_PLAYER|IDLE_MIXER|IDLE_OUTPUT) &&
-	    instance->state_file != nullptr)
-		instance->state_file->CheckModified();
+	    state_file != nullptr)
+		state_file->CheckModified();
 }
 
 #ifndef ANDROID
@@ -517,8 +512,6 @@ static int mpd_main_after_fork(struct options options)
 try {
 	Error error;
 
-	instance->global_events.Register(GlobalEvents::IDLE, idle_event_emitted);
-
 	if (!ConfigureFS(error)) {
 		LogError(error);
 		return EXIT_FAILURE;