print_volume(linux): Open a new mixer every time.

This fix the following bug:
    If you switch your sound card on-the-fly, print_volume continued to
    use the old sound card.

1 files changed, 52 insertions, 103 deletions

diff --git a/src/print_volume.c b/src/print_volume.c
index d3a9708..d84b3ec 100644
--- a/src/print_volume.c
+++ b/src/print_volume.c
@@ -26,29 +26,6 @@
 #include "i3status.h"
 #include "queue.h"
 
-#ifdef LINUX
-struct mixer_hdl {
-	char *device;
-	char *mixer;
-	int mixer_idx;
-	snd_mixer_selem_id_t *sid;
-	snd_mixer_t *m;
-	snd_mixer_elem_t *elem;
-	long min;
-	long max;
-
-	TAILQ_ENTRY(mixer_hdl) handles;
-};
-
-TAILQ_HEAD(handles_head, mixer_hdl) cached = TAILQ_HEAD_INITIALIZER(cached);
-
-static void free_hdl(struct mixer_hdl *hdl) {
-	free(hdl->device);
-	free(hdl->mixer);
-	free(hdl);
-}
-#endif
-
 void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *device, const char *mixer, int mixer_idx) {
         char *outwalk = buffer;
 	int pbval = 1;
@@ -61,100 +38,69 @@ void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *
                 free(instance);
         }
 #ifdef LINUX
-	/* Check if we already opened the mixer and get the handle
-	 * from cache if so */
-	bool found = false;
 	int err;
-	struct mixer_hdl *hdl;
-	TAILQ_FOREACH(hdl, &cached, handles) {
-		if (strcmp(hdl->device, device) != 0 ||
-		    strcmp(hdl->mixer, mixer) != 0 ||
-		    hdl->mixer_idx != mixer_idx)
-			continue;
-		found = true;
-		break;
-	}
-
-	if (!found) {
-		if ((hdl = calloc(sizeof(struct mixer_hdl), 1)) == NULL)
-			goto out;
-
-		if ((hdl->device = strdup(device)) == NULL) {
-			free(hdl);
-			goto out;
-		}
-
-		if ((hdl->mixer = strdup(mixer)) == NULL) {
-			free(hdl->device);
-			free(hdl);
-			goto out;
-		}
-
-		hdl->mixer_idx = mixer_idx;
-		snd_mixer_selem_id_malloc(&(hdl->sid));
-		if (hdl->sid == NULL) {
-			free_hdl(hdl);
-			goto out;
-		}
+	snd_mixer_t *m;
+	snd_mixer_selem_id_t *sid;
+	snd_mixer_elem_t *elem;
+	long min, max, val;
+	int avg;
 
-		if ((err = snd_mixer_open(&(hdl->m), 0)) < 0) {
-			fprintf(stderr, "i3status: ALSA: Cannot open mixer: %s\n", snd_strerror(err));
-			free_hdl(hdl);
-			goto out;
-		}
+	if ((err = snd_mixer_open(&m, 0)) < 0) {
+		fprintf(stderr, "i3status: ALSA: Cannot open mixer: %s\n", snd_strerror(err));
+		goto out;
+	}
 
-		/* Attach this mixer handle to the given device */
-		if ((err = snd_mixer_attach(hdl->m, device)) < 0) {
-			fprintf(stderr, "i3status: ALSA: Cannot attach mixer to device: %s\n", snd_strerror(err));
-			snd_mixer_close(hdl->m);
-			free_hdl(hdl);
-			goto out;
-		}
+	/* Attach this mixer handle to the given device */
+	if ((err = snd_mixer_attach(m, device)) < 0) {
+		fprintf(stderr, "i3status: ALSA: Cannot attach mixer to device: %s\n", snd_strerror(err));
+		snd_mixer_close(m);
+		goto out;
+	}
 
-		/* Register this mixer */
-		if ((err = snd_mixer_selem_register(hdl->m, NULL, NULL)) < 0) {
-			fprintf(stderr, "i3status: ALSA: snd_mixer_selem_register: %s\n", snd_strerror(err));
-			snd_mixer_close(hdl->m);
-			free_hdl(hdl);
-			goto out;
-		}
+	/* Register this mixer */
+	if ((err = snd_mixer_selem_register(m, NULL, NULL)) < 0) {
+		fprintf(stderr, "i3status: ALSA: snd_mixer_selem_register: %s\n", snd_strerror(err));
+		snd_mixer_close(m);
+		goto out;
+	}
 
-		if ((err = snd_mixer_load(hdl->m)) < 0) {
-			fprintf(stderr, "i3status: ALSA: snd_mixer_load: %s\n", snd_strerror(err));
-			snd_mixer_close(hdl->m);
-			free_hdl(hdl);
-			goto out;
-		}
+	if ((err = snd_mixer_load(m)) < 0) {
+		fprintf(stderr, "i3status: ALSA: snd_mixer_load: %s\n", snd_strerror(err));
+		snd_mixer_close(m);
+		goto out;
+	}
 
-		/* Find the given mixer */
-		snd_mixer_selem_id_set_index(hdl->sid, mixer_idx);
-		snd_mixer_selem_id_set_name(hdl->sid, mixer);
-		if (!(hdl->elem = snd_mixer_find_selem(hdl->m, hdl->sid))) {
-			fprintf(stderr, "i3status: ALSA: Cannot find mixer %s (index %i)\n",
-				snd_mixer_selem_id_get_name(hdl->sid), snd_mixer_selem_id_get_index(hdl->sid));
-			snd_mixer_close(hdl->m);
-			free_hdl(hdl);
-			goto out;
-		}
+	snd_mixer_selem_id_malloc(&sid);
+	if (sid == NULL) {
+		snd_mixer_close(m);
+		goto out;
+	}
 
-		/* Get the volume range to convert the volume later */
-		snd_mixer_selem_get_playback_volume_range(hdl->elem, &(hdl->min), &(hdl->max));
-		TAILQ_INSERT_TAIL(&cached, hdl, handles);
+	/* Find the given mixer */
+	snd_mixer_selem_id_set_index(sid, mixer_idx);
+	snd_mixer_selem_id_set_name(sid, mixer);
+	if (!(elem = snd_mixer_find_selem(m, sid))) {
+		fprintf(stderr, "i3status: ALSA: Cannot find mixer %s (index %i)\n",
+			snd_mixer_selem_id_get_name(sid), snd_mixer_selem_id_get_index(sid));
+		snd_mixer_close(m);
+		snd_mixer_selem_id_free(sid);
+		goto out;
 	}
 
-	long val;
-	snd_mixer_handle_events (hdl->m);
-	snd_mixer_selem_get_playback_volume (hdl->elem, 0, &val);
-	int avg;
-	if (hdl->max != 100) {
-		float avgf = ((float)val / hdl->max) * 100;
+	/* Get the volume range to convert the volume later */
+	snd_mixer_selem_get_playback_volume_range(elem, &min, &max);
+
+	snd_mixer_handle_events (m);
+	snd_mixer_selem_get_playback_volume (elem, 0, &val);
+	if (max != 100) {
+		float avgf = ((float)val / max) * 100;
 		avg = (int)avgf;
 		avg = (avgf - avg < 0.5 ? avg : (avg+1));
 	} else avg = (int)val;
 
 	/* Check for mute */
-	if (snd_mixer_selem_has_playback_switch(hdl->elem)) {
-		if ((err = snd_mixer_selem_get_playback_switch(hdl->elem, 0, &pbval)) < 0)
+	if (snd_mixer_selem_has_playback_switch(elem)) {
+		if ((err = snd_mixer_selem_get_playback_switch(elem, 0, &pbval)) < 0)
 			fprintf (stderr, "i3status: ALSA: playback_switch: %s\n", snd_strerror(err));
 		if (!pbval)  {
 			START_COLOR("color_degraded");
@@ -162,6 +108,9 @@ void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *
 		}
 	}
 
+	snd_mixer_close(m);
+	snd_mixer_selem_id_free(sid);
+
 	const char *walk = fmt;
 	for (; *walk != '\0'; walk++) {
 		if (*walk != '%') {