[dacp] Support for dmcp.device-prevent-playback (issue #855)

src/dacp_prop.gperf

@@ -12,6 +12,7 @@ struct dacp_prop_map;
 %%
 "dmcp.volume",                          dacp_propget_volume,                 dacp_propset_volume
 "dmcp.device-volume",                   NULL,                                dacp_propset_devicevolume
+"dmcp.device-prevent-playback",         NULL,                                dacp_propset_devicepreventplayback
 "dacp.playerstate",                     dacp_propget_playerstate,            NULL
 "dacp.nowplaying",                      dacp_propget_nowplaying,             NULL
 "dacp.playingtime",                     dacp_propget_playingtime,            dacp_propset_playingtime

src/httpd_dacp.c

@@ -112,6 +112,8 @@ dacp_propset_volume(const char *value, struct httpd_request *hreq);
 static void
 dacp_propset_devicevolume(const char *value, struct httpd_request *hreq);
 static void
+dacp_propset_devicepreventplayback(const char *value, struct httpd_request *hreq);
+static void
 dacp_propset_playingtime(const char *value, struct httpd_request *hreq);
 static void
 dacp_propset_shufflestate(const char *value, struct httpd_request *hreq);
@@ -957,19 +959,68 @@ static void
 dacp_propset_devicevolume(const char *value, struct httpd_request *hreq)
 {
   struct evkeyvalq *headers;
+  struct player_speaker_info spk_info;
   const char *remote;
-  uint32_t id;
+  uint32_t active_remote;
+  int ret;
 
   headers = evhttp_request_get_input_headers(hreq->req);
   remote = evhttp_find_header(headers, "Active-Remote");
 
-  if (!headers || !remote || (safe_atou32(remote, &id) < 0))
+  if (!headers || !remote || (safe_atou32(remote, &active_remote) < 0))
     {
       DPRINTF(E_LOG, L_DACP, "Request for setting device-volume has invalid Active-Remote: '%s'\n", remote);
       return;
     }
 
-  player_volume_byactiveremote(id, value);
+  ret = player_speaker_get_byactiveremote(&spk_info, active_remote);
+  if (ret < 0)
+    {
+      DPRINTF(E_LOG, L_DACP, "Request for setting device-volume from unknown Active-Remote: '%s'\n", remote);
+      return;
+    }
+
+  player_volume_update_speaker(spk_info.id, value);
+}
+
+// iTunes seems to use this as way for a speaker to tell the server that it is
+// busy with something else. If the speaker makes the request with the value 1,
+// then iTunes will disable the speaker, and if it is the only speaker, then
+// playback will also be paused. It is not possible for the user to restart the
+// speaker until it has made a request with value 0 (if attempted, iTunes will
+// show it is waiting for the speaker). As you can see from the below, we
+// don't fully match this behaviour, instead we just enable/disable.
+static void
+dacp_propset_devicepreventplayback(const char *value, struct httpd_request *hreq)
+{
+  struct evkeyvalq *headers;
+  struct player_speaker_info spk_info;
+  const char *remote;
+  uint32_t active_remote;
+  int ret;
+
+  headers = evhttp_request_get_input_headers(hreq->req);
+  remote = evhttp_find_header(headers, "Active-Remote");
+
+  if (!headers || !remote || (safe_atou32(remote, &active_remote) < 0))
+    {
+      DPRINTF(E_LOG, L_DACP, "Request for setting device-prevent-playback has invalid Active-Remote: '%s'\n", remote);
+      return;
+    }
+
+  ret = player_speaker_get_byactiveremote(&spk_info, active_remote);
+  if (ret < 0)
+    {
+      DPRINTF(E_LOG, L_DACP, "Request for setting device-prevent-playback from unknown Active-Remote: '%s'\n", remote);
+      return;
+    }
+
+  if (value[0] == '1')
+    player_speaker_disable(spk_info.id);
+  else if (value[0] == '0')
+    player_speaker_enable(spk_info.id);
+  else
+    DPRINTF(E_LOG, L_DACP, "Request for setting device-prevent-playback has invalid value: '%s'\n", value);
 }
 
 static void
@@ -2433,11 +2484,12 @@ dacp_reply_setproperty(struct httpd_request *hreq)
     return -1;
 
   /* Known properties (see dacp_prop.gperf):
-   * dacp.shufflestate  0/1
+   * dacp.shufflestate                0/1
-   * dacp.repeatstate   0/1/2
+   * dacp.repeatstate                 0/1/2
-   * dacp.playingtime   seek to time in ms
+   * dacp.playingtime                 seek to time in ms
-   * dmcp.volume        0-100, float
+   * dmcp.volume                      0-100, float
-   * dmcp.device-volume -144-0, float (raop volume)
+   * dmcp.device-volume               -144-0, float (raop volume)
+   * dmcp.device-prevent-playback     0/1
    */
 
   /* /ctrl-int/1/setproperty?dacp.shufflestate=1&session-id=100 */

src/player.c

@@ -113,12 +113,8 @@
 //#define DEBUG_PLAYER 1
 
 struct volume_param {
-  int volume;
   uint64_t spk_id;
-};
+  int volume;
-
-struct activeremote_param {
-  uint32_t activeremote;
   const char *value;
 };
 
@@ -137,6 +133,7 @@ struct speaker_set_param
 struct speaker_get_param
 {
   uint64_t spk_id;
+  uint32_t active_remote;
   struct player_speaker_info *spk_info;
 };
 
@@ -2392,6 +2389,7 @@ device_to_speaker_info(struct player_speaker_info *spk, struct output_device *de
 {
   memset(spk, 0, sizeof(struct player_speaker_info));
   spk->id = device->id;
+  spk->active_remote = (uint32_t)device->id;
   strncpy(spk->name, device->name, sizeof(spk->name));
   spk->name[sizeof(spk->name) - 1] = '\0';
   strncpy(spk->output_type, device->type_name, sizeof(spk->output_type));
@@ -2445,6 +2443,27 @@ speaker_get_byid(void *arg, int *retval)
   return COMMAND_END;
 }
 
+static enum command_state
+speaker_get_byactiveremote(void *arg, int *retval)
+{
+  struct speaker_get_param *spk_param = arg;
+  struct output_device *device;
+
+  for (device = output_device_list; device; device = device->next)
+    {
+      if ((uint32_t)device->id == spk_param->active_remote)
+	{
+	  device_to_speaker_info(spk_param->spk_info, device);
+	  *retval = 0;
+	  return COMMAND_END;
+	}
+    }
+
+  // No output device found with matching id
+  *retval = -1;
+  return COMMAND_END;
+}
+
 static int
 speaker_activate(struct output_device *device)
 {
@@ -2770,33 +2789,23 @@ volume_setabs_speaker(void *arg, int *retval)
 
 // Just updates internal volume params (does not make actual requests to the speaker)
 static enum command_state
-volume_byactiveremote(void *arg, int *retval)
+volume_update_speaker(void *arg, int *retval)
 {
-  struct activeremote_param *ar_param = arg;
+  struct volume_param *vol_param = arg;
   struct output_device *device;
-  uint32_t activeremote;
   int volume;
 
-  *retval = 0;
+  device = outputs_device_get(vol_param->spk_id);
-  activeremote = ar_param->activeremote;
-
-  for (device = output_device_list; device; device = device->next)
-    {
-      if ((uint32_t)device->id == activeremote)
-	break;
-    }
-
   if (!device)
     {
-      DPRINTF(E_LOG, L_DACP, "Could not find speaker with Active-Remote id %d\n", activeremote);
       *retval = -1;
       return COMMAND_END;
     }
 
-  volume = outputs_device_volume_to_pct(device, ar_param->value); // Only converts
+  volume = outputs_device_volume_to_pct(device, vol_param->value); // Only converts
   if (volume < 0)
     {
-      DPRINTF(E_LOG, L_DACP, "Could not parse volume given by Active-Remote id %d\n", activeremote);
+      DPRINTF(E_LOG, L_DACP, "Could not parse volume '%s' in update_volume() for speaker '%s'\n", vol_param->value, device->name);
       *retval = -1;
       return COMMAND_END;
     }
@@ -2811,6 +2820,7 @@ volume_byactiveremote(void *arg, int *retval)
 
   listener_notify(LISTENER_VOLUME);
 
+  *retval = 0;
   return COMMAND_END;
 }
 
@@ -3111,6 +3121,19 @@ player_speaker_get_byid(uint64_t id, struct player_speaker_info *spk)
   return ret;
 }
 
+int
+player_speaker_get_byactiveremote(struct player_speaker_info *spk, uint32_t active_remote)
+{
+  struct speaker_get_param param;
+  int ret;
+
+  param.active_remote = active_remote;
+  param.spk_info = spk;
+
+  ret = commands_exec_sync(cmdbase, speaker_get_byactiveremote, NULL, &param);
+  return ret;
+}
+
 int
 player_speaker_enable(uint64_t id)
 {
@@ -3192,15 +3215,15 @@ player_volume_setabs_speaker(uint64_t id, int vol)
 }
 
 int
-player_volume_byactiveremote(uint32_t activeremote, const char *value)
+player_volume_update_speaker(uint64_t id, const char *value)
 {
-  struct activeremote_param ar_param;
+  struct volume_param vol_param;
   int ret;
 
-  ar_param.activeremote = activeremote;
+  vol_param.spk_id = id;
-  ar_param.value = value;
+  vol_param.value  = value;
 
-  ret = commands_exec_sync(cmdbase, volume_byactiveremote, NULL, &ar_param);
+  ret = commands_exec_sync(cmdbase, volume_update_speaker, NULL, &vol_param);
   return ret;
 }
 

src/player.h

@@ -29,6 +29,7 @@ enum player_seek_mode {
 
 struct player_speaker_info {
   uint64_t id;
+  uint32_t active_remote;
   char name[255];
   char output_type[50];
   int relvol;
@@ -92,6 +93,9 @@ player_speaker_set(uint64_t *ids);
 int
 player_speaker_get_byid(uint64_t id, struct player_speaker_info *spk);
 
+int
+player_speaker_get_byactiveremote(struct player_speaker_info *spk, uint32_t active_remote);
+
 int
 player_speaker_enable(uint64_t id);
 
@@ -132,7 +136,7 @@ int
 player_volume_setabs_speaker(uint64_t id, int vol);
 
 int
-player_volume_byactiveremote(uint32_t activeremote, const char *value);
+player_volume_update_speaker(uint64_t id, const char *value);
 
 int
 player_repeat_set(enum repeat_mode mode);