libpulse: introduce PA_STREAM_RELATIVE_VOLUME

PROTOCOL

@@ -188,3 +188,9 @@ new messages:
 
   PA_COMMAND_SET_SINK_PORT
   PA_COMMAND_SET_SOURCE_PORT
+
+## v17, implemented by >= 0.9.20
+
+new flag at end of CREATE_PLAYBACK_STREAM:
+
+    bool relative_volume

configure.ac

@@ -40,7 +40,7 @@ AC_SUBST(PA_MAJORMINORMICRO, pa_major.pa_minor.pa_micro)
 AC_SUBST(PACKAGE_URL, [http://pulseaudio.org/])
 
 AC_SUBST(PA_API_VERSION, 12)
-AC_SUBST(PA_PROTOCOL_VERSION, 16)
+AC_SUBST(PA_PROTOCOL_VERSION, 17)
 
 # The stable ABI for client applications, for the version info x:y:z
 # always will hold y=z

src/pulse/def.h

@@ -276,11 +276,18 @@ typedef enum pa_stream_flags {
      * whether to create the stream in muted or in unmuted
      * state. \since 0.9.15 */
 
-    PA_STREAM_FAIL_ON_SUSPEND = 0x20000U
+    PA_STREAM_FAIL_ON_SUSPEND = 0x20000U,
     /**< If the sink/source this stream is connected to is suspended
      * during the creation of this stream, cause it to fail. If the
      * sink/source is being suspended during creation of this stream,
      * make sure this stream is terminated. \since 0.9.15 */
+
+    PA_STREAM_RELATIVE_VOLUME = 0x40000U,
+    /**< If a volume is passed when this stream is created, consider
+     * it relative to the sink's current volume, never as absolute
+     * device volume. If this is not specified the volume will be
+     * consider absolute when the sink is in flat volume mode,
+     * relative otherwise. \since 0.9.20 */
 } pa_stream_flags_t;
 
 /** \cond fulldocs */
@@ -307,6 +314,7 @@ typedef enum pa_stream_flags {
 #define PA_STREAM_DONT_INHIBIT_AUTO_SUSPEND PA_STREAM_DONT_INHIBIT_AUTO_SUSPEND
 #define PA_STREAM_START_UNMUTED PA_STREAM_START_UNMUTED
 #define PA_STREAM_FAIL_ON_SUSPEND PA_STREAM_FAIL_ON_SUSPEND
+#define PA_STREAM_RELATIVE_VOLUME PA_STREAM_RELATIVE_VOLUME
 
 /** \endcond */
 

src/pulse/stream.c

@@ -1025,7 +1025,8 @@ static int create_stream(
                                               PA_STREAM_EARLY_REQUESTS|
                                               PA_STREAM_DONT_INHIBIT_AUTO_SUSPEND|
                                               PA_STREAM_START_UNMUTED|
-                                              PA_STREAM_FAIL_ON_SUSPEND)), PA_ERR_INVALID);
+                                              PA_STREAM_FAIL_ON_SUSPEND|
+                                              PA_STREAM_RELATIVE_VOLUME)), PA_ERR_INVALID);
 
     PA_CHECK_VALIDITY(s->context, s->context->version >= 12 || !(flags & PA_STREAM_VARIABLE_RATE), PA_ERR_NOTSUPPORTED);
     PA_CHECK_VALIDITY(s->context, s->context->version >= 13 || !(flags & PA_STREAM_PEAK_DETECT), PA_ERR_NOTSUPPORTED);
@@ -1158,6 +1159,13 @@ static int create_stream(
         pa_tagstruct_put_boolean(t, flags & PA_STREAM_FAIL_ON_SUSPEND);
     }
 
+    if (s->context->version >= 17) {
+
+        if (s->direction == PA_STREAM_PLAYBACK)
+            pa_tagstruct_put_boolean(t, flags & PA_STREAM_RELATIVE_VOLUME);
+
+    }
+
     pa_pstream_send_tagstruct(s->context->pstream, t);
     pa_pdispatch_register_reply(s->context->pdispatch, tag, DEFAULT_TIMEOUT, pa_create_stream_callback, s, NULL);
 

src/pulsecore/protocol-native.c

@@ -1002,6 +1002,7 @@ static playback_stream* playback_stream_new(
         pa_proplist *p,
         pa_bool_t adjust_latency,
         pa_bool_t early_requests,
+        pa_bool_t relative_volume,
         int *ret) {
 
     playback_stream *s, *ssync;
@@ -1052,7 +1053,7 @@ static playback_stream* playback_stream_new(
     pa_sink_input_new_data_set_channel_map(&data, map);
     if (volume) {
         pa_sink_input_new_data_set_volume(&data, volume);
-        data.volume_is_absolute = TRUE;
+        data.volume_is_absolute = !relative_volume;
         data.save_volume = TRUE;
     }
     if (muted_set) {
@@ -1846,7 +1847,8 @@ static void command_create_playback_stream(pa_pdispatch *pd, uint32_t command, u
         early_requests = FALSE,
         dont_inhibit_auto_suspend = FALSE,
         muted_set = FALSE,
-        fail_on_suspend = FALSE;
+        fail_on_suspend = FALSE,
+        relative_volume = FALSE;
     pa_sink_input_flags_t flags = 0;
     pa_proplist *p;
     pa_bool_t volume_set = TRUE;
@@ -1939,6 +1941,15 @@ static void command_create_playback_stream(pa_pdispatch *pd, uint32_t command, u
         }
     }
 
+    if (c->version >= 17) {
+
+        if (pa_tagstruct_get_boolean(t, &relative_volume) < 0) {
+            protocol_error(c);
+            pa_proplist_free(p);
+            return;
+        }
+    }
+
     if (!pa_tagstruct_eof(t)) {
         protocol_error(c);
         pa_proplist_free(p);
@@ -1978,7 +1989,7 @@ static void command_create_playback_stream(pa_pdispatch *pd, uint32_t command, u
      * flag. For older versions we synthesize it here */
     muted_set = muted_set || muted;
 
-    s = playback_stream_new(c, sink, &ss, &map, &attr, volume_set ? &volume : NULL, muted, muted_set, syncid, &missing, flags, p, adjust_latency, early_requests, &ret);
+    s = playback_stream_new(c, sink, &ss, &map, &attr, volume_set ? &volume : NULL, muted, muted_set, syncid, &missing, flags, p, adjust_latency, early_requests, relative_volume, &ret);
     pa_proplist_free(p);
 
     CHECK_VALIDITY(c->pstream, s, tag, ret);