EventPipe: rename to GlobalEvents

src/GlobalEvents.cxx

@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 2003-2013 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.
+ */
+
+#include "config.h"
+#include "GlobalEvents.hxx"
+#include "thread/Mutex.hxx"
+#include "fd_util.h"
+#include "mpd_error.h"
+
+#include <assert.h>
+#include <glib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "global_events"
+
+namespace GlobalEvents {
+	static int fds[2];
+	static GIOChannel *channel;
+	static guint source_id;
+	static Mutex mutex;
+	static bool flags[MAX];
+	static Handler handlers[MAX];
+}
+
+/**
+ * Invoke the callback for a certain event.
+ */
+static void
+InvokeGlobalEvent(GlobalEvents::Event event)
+{
+	assert((unsigned)event < GlobalEvents::MAX);
+	assert(GlobalEvents::handlers[event] != NULL);
+
+	GlobalEvents::handlers[event]();
+}
+
+static gboolean
+GlobalEventCallback(G_GNUC_UNUSED GIOChannel *source,
+		    G_GNUC_UNUSED GIOCondition condition,
+		    G_GNUC_UNUSED gpointer data)
+{
+	char buffer[256];
+	gsize bytes_read;
+	GError *error = NULL;
+	GIOStatus status = g_io_channel_read_chars(GlobalEvents::channel,
+						   buffer, sizeof(buffer),
+						   &bytes_read, &error);
+	if (status == G_IO_STATUS_ERROR)
+		MPD_ERROR("error reading from pipe: %s", error->message);
+
+	bool events[GlobalEvents::MAX];
+	GlobalEvents::mutex.lock();
+	memcpy(events, GlobalEvents::flags, sizeof(events));
+	memset(GlobalEvents::flags, 0,
+	       sizeof(GlobalEvents::flags));
+	GlobalEvents::mutex.unlock();
+
+	for (unsigned i = 0; i < GlobalEvents::MAX; ++i)
+		if (events[i])
+			/* invoke the event handler */
+			InvokeGlobalEvent(GlobalEvents::Event(i));
+
+	return true;
+}
+
+void
+GlobalEvents::Initialize()
+{
+	if (pipe_cloexec_nonblock(fds) < 0)
+		MPD_ERROR("Couldn't open pipe: %s", strerror(errno));
+
+#ifndef G_OS_WIN32
+	channel = g_io_channel_unix_new(fds[0]);
+#else
+	channel = g_io_channel_win32_new_fd(fds[0]);
+#endif
+	g_io_channel_set_encoding(channel, NULL, NULL);
+	g_io_channel_set_buffered(channel, false);
+
+	source_id = g_io_add_watch(channel, G_IO_IN,
+				   GlobalEventCallback, NULL);
+}
+
+void
+GlobalEvents::Deinitialize()
+{
+	g_source_remove(source_id);
+	g_io_channel_unref(channel);
+
+#ifndef WIN32
+	/* By some strange reason this call hangs on Win32 */
+	close(fds[0]);
+#endif
+	close(fds[1]);
+}
+
+void
+GlobalEvents::Register(Event event, Handler callback)
+{
+	assert((unsigned)event < MAX);
+	assert(handlers[event] == NULL);
+
+	handlers[event] = callback;
+}
+
+void
+GlobalEvents::Emit(Event event)
+{
+	assert((unsigned)event < MAX);
+
+	mutex.lock();
+	if (flags[event]) {
+		/* already set: don't write */
+		mutex.unlock();
+		return;
+	}
+
+	flags[event] = true;
+	mutex.unlock();
+
+	ssize_t w = write(fds[1], "", 1);
+	if (w < 0 && errno != EAGAIN && errno != EINTR)
+		MPD_ERROR("error writing to pipe: %s", strerror(errno));
+}
+
+void
+GlobalEvents::FastEmit(Event event)
+{
+	assert((unsigned)event < MAX);
+
+	flags[event] = true;
+
+	G_GNUC_UNUSED ssize_t nbytes = write(fds[1], "", 1);
+}