ocarina: Listen for text written to a named pipe

If the text is "play", "pause", or "next" then I call the appropriate
libsaria function.  I eventually plan on adding more commands so bash
can act as a generic remote control, but for now this is a good start!

To use:  `echo play > ~/.config/saria[-debug]/saria.pipe` after creating
the fifo (see scripts/makepipe).

Signed-off-by: Bryan Schumaker <bjschuma@gmail.com>

include/ocarina/ocarina.h

@@ -7,6 +7,7 @@ namespace ocarina
 	void quit();
 	void idle_add();
 	string full_path(string);
+	void init_pipe();
 
 };
 

ocarina/ocarina.cpp

@@ -3,6 +3,7 @@
 #include <ocarina/callback.h>
 #include <ocarina/gtk.h>
 #include <ocarina/body.h>
+#include <ocarina/ocarina.h>
 #include <ocarina/settings.h>
 #include <ocarina/window.h>
 #include <ocarina/library.h>
@@ -81,6 +82,7 @@ int main(int argc, char **argv)
 
 	gtk_init(&argc, &argv);
 	ocarina::init(argc, argv);
+	ocarina::init_pipe();
 
 	if (argc > 1)
 		libsaria::audio::load(argv[1]);

ocarina/pipe.cpp

@@ -0,0 +1,58 @@
+// Copyright (c) Bryan Schumaker 2012.
+#include <libsaria/path.h>
+#include <libsaria/print.h>
+#include <libsaria/audio.h>
+#include <libsaria/controls.h>
+#include <ocarina/ocarina.h>
+
+#include <glib.h>
+
+static GIOChannel *pipe_in;
+
+void perform_action(string action)
+{
+	if (action == "play")
+		libsaria::audio::play();
+	else if (action == "pause")
+		libsaria::audio::pause();
+	else if (action == "next")
+		libsaria::next();
+}
+
+string pipe_read_text(GIOChannel *source)
+{
+	gchar *str = NULL;
+	GError *error = NULL;
+	gsize size, end;
+	string text;
+
+	g_io_channel_read_line(source, &str, &size, &end, &error);
+	text = str;
+
+	/* g_io_channel_read_line allocates memory */
+	g_free(str);
+	return text.substr(0, size-1);
+}
+
+gboolean pipe_read(GIOChannel *source, GIOCondition condition, gpointer data)
+{
+	string action = pipe_read_text(source);
+	perform_action(action);
+	return TRUE;
+}
+
+namespace ocarina
+{
+	void init_pipe()
+	{
+		GError *error = NULL;
+		string pipe = get_pipe_file();
+		if (pipe == "")
+			return;
+
+		pipe_in = g_io_channel_new_file(pipe.c_str(), "r+", &error);
+		if (!pipe_in)
+			return;
+		g_io_add_watch(pipe_in, G_IO_IN, pipe_read, NULL);
+	}
+}