From 78bc1362e852f52507c88ee3c987004d8007fac7 Mon Sep 17 00:00:00 2001
From: Jason Woofenden <jason@jasonwoof.com>
Date: Sat, 13 Feb 2010 12:06:32 -0500
Subject: [PATCH] read stdin instead of polling a text file

---
 Makefile        |    2 +-
 README          |   50 ++++++++++++++++++++++++++++++++++++----------
 now-playing-d.c |   59 ++++++++++++++++++++++++++++++++++++++-----------------
 3 files changed, 82 insertions(+), 29 deletions(-)

diff --git a/Makefile b/Makefile
index d2d6a53..3fb709c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 now-playing-d: now-playing-d.c eggtrayicon.c eggtrayicon.h
-	gcc -D"TMP_FILE=\"$(HOME)/tmp/now-playing\"" `pkg-config --cflags --libs gtk+-2.0` eggtrayicon.c now-playing-d.c -o $@
+	gcc `pkg-config --cflags --libs gtk+-2.0` eggtrayicon.c now-playing-d.c -o $@
 
 install: now-playing-d
 	cp now-playing-d "$(HOME)/bin/"
diff --git a/README b/README
index 084fda0..6ea8e36 100644
--- a/README
+++ b/README
@@ -1,15 +1,45 @@
-This is a very simple program which displays one line of text in the
-notification area.
+now-playing-d
 
-It reads a file (~/tmp/now-playing) every second, and displays the contents in
-the notification area. For best results, make sure there's no newlines in the
-file, and that there's not too much text.
+NAME
+	now-playing-d - display text from stdin in the notification area.
 
-You can build it with this command: make
+DESCRIPTION
 
-And install it in your ~/bin with this command: make install
+	now-playind-d reads from stdin. Whenever a full new line is read, this
+	text is displayed in the notification area (replacing any text
+	now-playing-d put there before, if any).
+	
+	Careful not to make the lines too long for your notification area.
 
-This program is licensed under the GNU GPLv3+.
+BUILDING
 
-This download also contains a copy of eggtrayicon by Anders Carlsson, which is
-licensed under the GNU LGPLv2+
+	make
+
+
+INSTALLING
+
+	To install to ~/bin:
+
+	make install
+
+	or just copy now-playing-d wherever you like
+
+
+USAGE
+
+	Here's an example of how to make it so you can "echo" text to it from scripts:
+
+	mkfifo ~/tmp/now-playing
+	while true; do cat ~/tmp/now-playing; done | now-playing-d
+
+	echo 'Hello, world!' > ~/tmp/now-playing
+	sleep 2
+	echo 'another message' > ~/tmp/now-playing
+
+
+LICENSING
+
+	This program is licensed under the GNU GPLv3+.
+
+	This download also contains a copy of eggtrayicon by Anders Carlsson,
+	which is licensed under the GNU LGPLv2+
diff --git a/now-playing-d.c b/now-playing-d.c
index 7b2ec06..9ac043d 100644
--- a/now-playing-d.c
+++ b/now-playing-d.c
@@ -20,34 +20,52 @@
 #include "eggtrayicon.h"
 
 
-char buf[1000];
-char* playing[2] = {&buf[0], &buf[500]};
+gchar* playing[2];
 int playing_i = 0;
 
 
 // this gets called regularly by gtk
-static gboolean
-ticker(GtkWidget *widget) {
-	FILE * fd;
-	int len;
+gboolean
+stdin_callback(GIOChannel *channel, GIOCondition cond, gpointer data) {
+	GtkWidget *widget;
+	GIOStatus ret;
+	gsize length;
+	gsize terminator_pos;
+	GError *error = NULL;
+
+	widget = GTK_WIDGET(data);
 
 	if (widget->window == NULL) {
 		return FALSE;
 	}
 
-	fd = fopen(TMP_FILE, "r");
-	if(fd == NULL) {
-		return TRUE;
+	ret = g_io_channel_read_line(
+		channel,
+		&(playing[playing_i]),
+		&length,
+		&terminator_pos,
+		&error);
+
+	if (ret == G_IO_STATUS_ERROR) {
+		g_error ("Error reading: %s\n", error->message);
+		gtk_exit(2);
+	}
+	if (length == 0) {
+		gtk_exit(0);
 	}
-	len = fread(playing[playing_i], 1, 499, fd);
-	fclose(fd);
-	playing[playing_i][len] = 0;
 
-	if(strcmp(playing[playing_i], playing[1 - playing_i])) {
+	// remove terminator
+	if(terminator_pos) {
+		playing[playing_i][terminator_pos] = 0;
+	}
+
+
+	if(strcmp(playing[0], playing[1])) {
 		gtk_label_set_text(GTK_LABEL(widget), playing[playing_i]);
 	}
 
 	playing_i = 1 - playing_i;
+	g_free(playing[playing_i]);
 
 	// gtk_widget_queue_draw(widget);
 	return TRUE;
@@ -58,22 +76,27 @@ int
 main(int argc, char *argv[]) {
 	GtkWidget *label;
 	EggTrayIcon *egg;
+	GIOChannel *channel;
 
 	// initialize GTK
 	gtk_set_locale();
 	gtk_init(&argc, &argv);
 
+	// initialize globals
+	playing_i = 0;
+	playing[1] = g_strdup("");
+
 	// make the widget
-	label = gtk_label_new("initializing...");
+	label = gtk_label_new("");
 	egg = egg_tray_icon_new("what's this string do?");
 	// nest and display the widget
 	gtk_container_add(GTK_CONTAINER(egg), label);
 	gtk_widget_show_all(GTK_WIDGET(egg));
 
-	// initialize and start ticker
-	playing[0][0] = 0;
-	playing[1][0] = 0;
-	g_timeout_add(1000, (GSourceFunc) ticker, (gpointer) label);
+	// watch stdin
+	channel = g_io_channel_unix_new(fileno(stdin));
+	g_io_channel_set_encoding(channel, NULL, NULL); // kiss
+	g_io_add_watch(channel, G_IO_IN, stdin_callback, (gpointer)label);
 
 	gtk_main();
 }
-- 
1.7.10.4