core: introduce pa_{sink,source}_set_fixed_latency()

This allows us to forward the fixed latency directly from the sink to
the monitor source withut having to wait for pa_sink_put().

src/pulsecore/sink.c

@@ -2050,6 +2050,22 @@ void pa_sink_set_latency_range_within_thread(pa_sink *s, pa_usec_t min_latency,
     pa_source_set_latency_range_within_thread(s->monitor_source, min_latency, max_latency);
 }
 
+/* Called from main thread, before the sink is put */
+void pa_sink_set_fixed_latency(pa_sink *s, pa_usec_t latency) {
+    pa_sink_assert_ref(s);
+
+    pa_assert(pa_sink_get_state(s) == PA_SINK_INIT);
+
+    if (latency < ABSOLUTE_MIN_LATENCY)
+        latency = ABSOLUTE_MIN_LATENCY;
+
+    if (latency > ABSOLUTE_MAX_LATENCY)
+        latency = ABSOLUTE_MAX_LATENCY;
+
+    s->fixed_latency = latency;
+    pa_source_set_fixed_latency(s->monitor_source, latency);
+}
+
 /* Called from main context */
 size_t pa_sink_get_max_rewind(pa_sink *s) {
     size_t r;

src/pulsecore/sink.h

@@ -229,6 +229,7 @@ void pa_sink_set_rtpoll(pa_sink *s, pa_rtpoll *p);
 void pa_sink_set_max_rewind(pa_sink *s, size_t max_rewind);
 void pa_sink_set_max_request(pa_sink *s, size_t max_request);
 void pa_sink_set_latency_range(pa_sink *s, pa_usec_t min_latency, pa_usec_t max_latency);
+void pa_sink_set_fixed_latency(pa_sink *s, pa_usec_t latency);
 
 void pa_sink_detach(pa_sink *s);
 void pa_sink_attach(pa_sink *s);

src/pulsecore/source.c

@@ -1276,6 +1276,21 @@ void pa_source_set_latency_range_within_thread(pa_source *s, pa_usec_t min_laten
     pa_source_invalidate_requested_latency(s);
 }
 
+/* Called from main thread, before the source is put */
+void pa_source_set_fixed_latency(pa_source *s, pa_usec_t latency) {
+    pa_source_assert_ref(s);
+
+    pa_assert(pa_source_get_state(s) == PA_SOURCE_INIT);
+
+    if (latency < ABSOLUTE_MIN_LATENCY)
+        latency = ABSOLUTE_MIN_LATENCY;
+
+    if (latency > ABSOLUTE_MAX_LATENCY)
+        latency = ABSOLUTE_MAX_LATENCY;
+
+    s->fixed_latency = latency;
+}
+
 /* Called from main thread */
 size_t pa_source_get_max_rewind(pa_source *s) {
     size_t r;

src/pulsecore/source.h

@@ -210,6 +210,7 @@ void pa_source_set_rtpoll(pa_source *s, pa_rtpoll *p);
 
 void pa_source_set_max_rewind(pa_source *s, size_t max_rewind);
 void pa_source_set_latency_range(pa_source *s, pa_usec_t min_latency, pa_usec_t max_latency);
+void pa_source_set_fixed_latency(pa_source *s, pa_usec_t latency);
 
 void pa_source_detach(pa_source *s);
 void pa_source_attach(pa_source *s);