Implement %devicename specifier for volume module (#325)

This commit implements the %devicename specifier for the volume module
for both PulseAudio and ALSA. This way, i3status will be able to display
the specific device that corresponds to the volume indicator.

Note that this is not implemented for the OSS API but is left in a state
where someone can pick it up for the future.

1 files changed, 36 insertions, 9 deletions

diff --git a/src/print_volume.c b/src/print_volume.c
index aa739a1..1d81e13 100644
--- a/src/print_volume.c
+++ b/src/print_volume.c
@@ -47,7 +47,7 @@
         fmt = fmt_muted;                                                                 \
     }
 
-static char *apply_volume_format(const char *fmt, char *outwalk, int ivolume) {
+static char *apply_volume_format(const char *fmt, char *outwalk, int ivolume, const char *devicename) {
     const char *walk = fmt;
 
     for (; *walk != '\0'; walk++) {
@@ -62,6 +62,10 @@ static char *apply_volume_format(const char *fmt, char *outwalk, int ivolume) {
             outwalk += sprintf(outwalk, "%d%s", ivolume, pct_mark);
             walk += strlen("volume");
 
+        } else if (BEGINS_WITH(walk + 1, "devicename")) {
+            outwalk += sprintf(outwalk, "%s", devicename);
+            walk += strlen("devicename");
+
         } else {
             *(outwalk++) = '%';
         }
@@ -93,36 +97,51 @@ void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *
                                         !isdigit(device[strlen("pulse:")])
                                     ? device + strlen("pulse:")
                                     : NULL;
-        int cvolume = pulse_initialize() ? volume_pulseaudio(sink_idx, sink_name) : 0;
+        int cvolume = 0;
+        char description[MAX_SINK_DESCRIPTION_LEN] = {'\0'};
+
+        if (pulse_initialize()) {
+            cvolume = volume_pulseaudio(sink_idx, sink_name);
+            /* false result means error, stick to empty-string */
+            if (!description_pulseaudio(sink_idx, sink_name, description)) {
+                description[0] = '\0';
+            }
+        }
+
         int ivolume = DECOMPOSE_VOLUME(cvolume);
         bool muted = DECOMPOSE_MUTED(cvolume);
         if (muted) {
             START_COLOR("color_degraded");
             pbval = 0;
         }
+
         /* negative result means error, stick to 0 */
         if (ivolume < 0)
             ivolume = 0;
         outwalk = apply_volume_format(muted ? fmt_muted : fmt,
                                       outwalk,
-                                      ivolume);
+                                      ivolume,
+                                      description);
         goto out;
     } else if (!strcasecmp(device, "default") && pulse_initialize()) {
         /* no device specified or "default" set */
+        char description[MAX_SINK_DESCRIPTION_LEN];
+        bool success = description_pulseaudio(DEFAULT_SINK_INDEX, NULL, description);
         int cvolume = volume_pulseaudio(DEFAULT_SINK_INDEX, NULL);
         int ivolume = DECOMPOSE_VOLUME(cvolume);
         bool muted = DECOMPOSE_MUTED(cvolume);
-        if (ivolume >= 0) {
+        if (ivolume >= 0 && success) {
             if (muted) {
                 START_COLOR("color_degraded");
                 pbval = 0;
             }
             outwalk = apply_volume_format(muted ? fmt_muted : fmt,
                                           outwalk,
-                                          ivolume);
+                                          ivolume,
+                                          description);
             goto out;
         }
-        /* negative result means error, fail PulseAudio attempt */
+        /* negative result or NULL description means error, fail PulseAudio attempt */
     }
 /* If some other device was specified or PulseAudio is not detected,
  * proceed to ALSA / OSS */
@@ -135,6 +154,7 @@ void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *
     snd_mixer_selem_id_t *sid;
     snd_mixer_elem_t *elem;
     long min, max, val;
+    const char *mixer_name;
     bool force_linear = false;
     int avg;
 
@@ -193,6 +213,12 @@ void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *
         goto out;
     }
 
+    mixer_name = snd_mixer_selem_get_name(elem);
+    if (!mixer_name) {
+        fprintf(stderr, "i3status: ALSA: NULL mixer_name.\n");
+        goto out;
+    }
+
     /* Use linear mapping for raw register values or small ranges of 24 dB */
     if (force_linear || max - min <= MAX_LINEAR_DB_SCALE * 100) {
         float avgf = ((float)(val - min) / (max - min)) * 100;
@@ -215,16 +241,17 @@ void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *
         ALSA_MUTE_SWITCH(capture)
     }
 
+    outwalk = apply_volume_format(fmt, outwalk, avg, mixer_name);
+
     snd_mixer_close(m);
     snd_mixer_selem_id_free(sid);
 
-    outwalk = apply_volume_format(fmt, outwalk, avg);
-
 #endif
 #if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
     char *mixerpath;
     char defaultmixer[] = "/dev/mixer";
     int mixfd, vol, devmask = 0;
+    const char *devicename = "UNSUPPORTED"; /* TODO: implement support for this */
     pbval = 1;
 
     if (mixer_idx > 0)
@@ -326,7 +353,7 @@ void print_volume(yajl_gen json_gen, char *buffer, const char *fmt, const char *
     }
 
 #endif
-    outwalk = apply_volume_format(fmt, outwalk, vol & 0x7f);
+    outwalk = apply_volume_format(fmt, outwalk, vol & 0x7f, devicename);
     close(mixfd);
 #endif