Move ALSA code to separate file

alsa.c

+#include <glib.h>
+
+#include "panelcontrol.h"
+#include "alsa.h"
+
+static gboolean on_alsa_readable(GIOChannel *source, GIOCondition condition, gpointer data) {
+	fprintf(stdout, "source=%p cond=%i data=%p\n", (void *)source, condition, data);
+	snd_seq_t *seq = (snd_seq_t *)data;
+
+	snd_seq_event_t *ev;
+	while (1) {
+		int remaining = snd_seq_event_input(seq, &ev);
+		if (remaining == -EAGAIN) {
+			return TRUE;
+		} else if (remaining < 0) {
+			perror("Error reading sequencer input");
+		}
+
+		switch (ev->type) {
+			case SND_SEQ_EVENT_NOTEON:
+				fprintf(stdout, "button %i: %i\n", ev->data.note.note, ev->data.note.velocity > 0);
+				snd_seq_ev_set_subs(ev);
+				snd_seq_ev_set_direct(ev);
+				snd_seq_event_output_direct(seq, ev);
+				break;
+			case SND_SEQ_EVENT_CONTROLLER:
+				fprintf(stdout, "knob %i: %i\n", ev->data.control.param, ev->data.control.value);
+				break;
+		}
+		snd_seq_free_event(ev);
+	}
+
+	return TRUE;
+}
+
+static int port;
+
+void alsa(int source, snd_seq_t **seq_ret, int *port_ret) {
+	// connect to ALSA seq
+	snd_seq_t *seq;
+	if (snd_seq_open(&seq, "hw", SND_SEQ_OPEN_DUPLEX, SND_SEQ_NONBLOCK) < 0) {
+		fprintf(stderr, "Error opening ALSA sequencer.\n");
+		exit(1);
+	}
+	if (seq_ret) *seq_ret = seq;
+	snd_seq_set_client_name(seq, CLIENT_NAME);
+	int port = snd_seq_create_simple_port(seq, CLIENT_NAME,
+			SND_SEQ_PORT_CAP_WRITE|SND_SEQ_PORT_CAP_SUBS_WRITE
+			|SND_SEQ_PORT_CAP_READ|SND_SEQ_PORT_CAP_SUBS_READ,
+			SND_SEQ_PORT_TYPE_APPLICATION);
+	if (port < 0) {
+		fprintf(stderr, "Error creating sequencer port.\n");
+		exit(1);
+	}
+	if (port_ret) *port_ret = port;
+
+	// read from and write to panel device
+	snd_seq_connect_from(seq, port, source, 0);
+	snd_seq_connect_to(seq, port, source, 0);
+
+	// event loop
+	int npfd;
+	struct pollfd *pfd;
+
+
+	npfd = snd_seq_poll_descriptors_count(seq, POLLIN);
+	pfd = (struct pollfd *)alloca(npfd * sizeof(struct pollfd));
+	snd_seq_poll_descriptors(seq, pfd, npfd, POLLIN);
+
+	for (int i = 0; i < npfd; ++i) {
+		GIOChannel *ch = g_io_channel_unix_new(pfd[i].fd);
+		guint evsrcid = g_io_add_watch(ch, pfd[i].events, &on_alsa_readable, seq);
+	}
+}

alsa.h

+#include <alsa/asoundlib.h>
+
+void alsa(int source, snd_seq_t **seq_ret, int *port_ret);

meson.build

@@ -9,7 +9,7 @@ alsa = dependency('alsa')
 glib = dependency('glib-2.0')
 
 executable('panelcontrol',
-           ['panelcontrol.c', 'pa.c', 'pa_sink_input_watch_list.c'],
+           ['panelcontrol.c', 'alsa.c', 'pa.c', 'pa_sink_input_watch_list.c'],
 		   dependencies : [pa, alsa, glib],
            install : true)
 

panelcontrol.c

@@ -4,78 +4,10 @@
 #include <glib.h>
 
 #include "panelcontrol.h"
+#include "alsa.h"
 #include "pa.h"
 #include "pa_sink_input_watch_list.h"
 
-gboolean on_alsa_readable(GIOChannel *source, GIOCondition condition, gpointer data) {
-	fprintf(stdout, "source=%p cond=%i data=%p\n", (void *)source, condition, data);
-	snd_seq_t *seq = (snd_seq_t *)data;
-
-	snd_seq_event_t *ev;
-	while (1) {
-		int remaining = snd_seq_event_input(seq, &ev);
-		if (remaining == -EAGAIN) {
-			return TRUE;
-		} else if (remaining < 0) {
-			perror("Error reading sequencer input");
-		}
-
-		switch (ev->type) {
-			case SND_SEQ_EVENT_NOTEON:
-				fprintf(stdout, "button %i: %i\n", ev->data.note.note, ev->data.note.velocity > 0);
-				snd_seq_ev_set_subs(ev);
-				snd_seq_ev_set_direct(ev);
-				snd_seq_event_output_direct(seq, ev);
-				break;
-			case SND_SEQ_EVENT_CONTROLLER:
-				fprintf(stdout, "knob %i: %i\n", ev->data.control.param, ev->data.control.value);
-				break;
-		}
-		snd_seq_free_event(ev);
-	}
-
-	return TRUE;
-}
-
-static int port;
-
-snd_seq_t *alsa(int source) {
-	// connect to ALSA seq
-	snd_seq_t *seq;
-	if (snd_seq_open(&seq, "hw", SND_SEQ_OPEN_DUPLEX, SND_SEQ_NONBLOCK) < 0) {
-		fprintf(stderr, "Error opening ALSA sequencer.\n");
-		exit(1);
-	}
-	snd_seq_set_client_name(seq, CLIENT_NAME);
-	port = snd_seq_create_simple_port(seq, CLIENT_NAME,
-			SND_SEQ_PORT_CAP_WRITE|SND_SEQ_PORT_CAP_SUBS_WRITE
-			|SND_SEQ_PORT_CAP_READ|SND_SEQ_PORT_CAP_SUBS_READ,
-			SND_SEQ_PORT_TYPE_APPLICATION);
-	if (port < 0) {
-		fprintf(stderr, "Error creating sequencer port.\n");
-		exit(1);
-	}
-
-	// read from and write to panel device
-	snd_seq_connect_from(seq, port, source, 0);
-	snd_seq_connect_to(seq, port, source, 0);
-
-	// event loop
-	int npfd;
-	struct pollfd *pfd;
-
-
-	npfd = snd_seq_poll_descriptors_count(seq, POLLIN);
-	pfd = (struct pollfd *)alloca(npfd * sizeof(struct pollfd));
-	snd_seq_poll_descriptors(seq, pfd, npfd, POLLIN);
-
-	for (int i = 0; i < npfd; ++i) {
-		GIOChannel *ch = g_io_channel_unix_new(pfd[i].fd);
-		guint evsrcid = g_io_add_watch(ch, pfd[i].events, &on_alsa_readable, seq);
-	}
-
-	return seq;
-}
 
 //void toggle_mute(enum button button, void *userdata) {
 //	const char *name = (const char *)userdata;
@@ -106,7 +38,14 @@ snd_seq_t *alsa(int source) {
 //static const struct encoder_map_entry encoder_map[] = {
 //	{.encoder = ENC1, .sink_input = NULL, .action = &change_volume},
 //};
-void midi_button_led(snd_seq_t *seq, enum button button, enum button_led_state state) {
+
+
+struct seq_port {
+	snd_seq_t *seq;
+	int port;
+};
+
+void midi_button_led(snd_seq_t *seq, int port, enum button button, enum button_led_state state) {
 	snd_seq_event_t ev;
 	snd_seq_ev_clear(&ev);
 	snd_seq_ev_set_source(&ev, port);
@@ -117,13 +56,13 @@ void midi_button_led(snd_seq_t *seq, enum button button, enum button_led_state s
 }
 
 void show_mute_and_speakers(struct sink_input_watch *w) {
-	snd_seq_t *seq = w->userdata;
-	midi_button_led(seq, TOP1, w->mute ? BUTTON_LED_ON : BUTTON_LED_OFF);
+	struct seq_port *sp = w->userdata;
+	midi_button_led(sp->seq, sp->port, TOP1, w->mute ? BUTTON_LED_ON : BUTTON_LED_OFF);
 
 	uint32_t speakers = 3;
 	uint32_t headphones = 4;
 
-	midi_button_led(seq, BOTTOM1, w->sink == speakers ? BUTTON_LED_ON : BUTTON_LED_OFF);
+	midi_button_led(sp->seq, sp->port, BOTTOM1, w->sink == speakers ? BUTTON_LED_ON : BUTTON_LED_OFF);
 }
 
 int main(int argc, char *argv[]) {
@@ -133,10 +72,11 @@ int main(int argc, char *argv[]) {
 	}
 	int source = atoi(argv[1]);
 
-	snd_seq_t *seq = alsa(source);
+	struct seq_port sp;
+	alsa(source, &sp.seq, &sp.port);
 
 	struct sink_input_watch *mpd = sink_inputs_add_sink("mpd pulse");
-	mpd->userdata = seq;
+	mpd->userdata = &sp;
 	mpd->volume_changed = show_mute_and_speakers;
 
 	pa();