[dbusif] Add option to route sources first. MER#1725

Some devices (at least OnePlus X) need to have sources routed before
sinks to have properly functioning FM Radio. Add option to change the
routing order for these devices.

route_sources_first=<true|false> default to false.

src/dbusif.c

@@ -67,6 +67,7 @@ struct pa_policy_dbusif {
     char               *strrule; /* match rule to catch stream info signals */
     int                 regist;  /* wheter or not registered to policy daemon*/
     int                 re_regist;
+    bool                route_sources_first;
 };
 
 struct actdsc {                 /* action descriptor */
@@ -129,7 +130,8 @@ struct pa_policy_dbusif *pa_policy_dbusif_init(struct userdata *u,
                                                const char      *ifnam,
                                                const char      *mypath,
                                                const char      *pdpath,
-                                               const char      *pdnam)
+                                               const char      *pdnam,
+                                               bool             route_sources_first)
 {
     pa_module               *m = u->module;
     struct pa_policy_dbusif *dbusif = NULL;
@@ -141,6 +143,8 @@ struct pa_policy_dbusif *pa_policy_dbusif_init(struct userdata *u,
 
     dbusif = pa_xnew0(struct pa_policy_dbusif, 1);
 
+    dbusif->route_sources_first = route_sources_first;
+
     dbus_error_init(&error);
     dbusif->conn = pa_dbus_bus_get(m->core, DBUS_BUS_SYSTEM, &error);
 
@@ -734,6 +738,17 @@ static int audio_route_parser(struct userdata *u, DBusMessageIter *actit)
     num_moving = pa_policy_group_start_move_all(u);
     pa_log_debug("Policy groups moving: %d", num_moving);
 
+    if (u->dbusif->route_sources_first) {
+        /* Following works only if MAX_ROUTING_DECISIONS is 2, so make sure this is
+         * caught if the value ever changes. */
+        pa_assert_se(MAX_ROUTING_DECISIONS == 2);
+        if (num_decisions > 1 && decisions[0].class != pa_policy_route_to_source) {
+            struct routing_decision tmp = decisions[0];
+            decisions[0] = decisions[1];
+            decisions[1] = tmp;
+        }
+    }
+
     /* Set profiles and ports while the groups are detached. */
     for (i = 0; i < num_decisions; i++) {
         p = pa_proplist_new();

src/dbusif.h

@@ -7,7 +7,7 @@ struct pa_policy_dbusif;
 
 struct pa_policy_dbusif *pa_policy_dbusif_init(struct userdata *, const char *,
                                                const char *, const char *,
-                                               const char *);
+                                               const char *, bool);
 void pa_policy_dbusif_done(struct userdata *);
 void pa_policy_dbusif_send_device_state(struct userdata *, const char *, const char **, int);
 void pa_policy_dbusif_send_media_status(struct userdata *, const char *,

src/module-policy-enforcement.c

@@ -60,6 +60,7 @@ PA_MODULE_USAGE(
     "dbus_policyd_name=<policy daemon's name> "
     "null_sink_name=<name of the null sink> "
     "othermedia_preemption=<on|off> "
+    "route_sources_first=<true|false> Default false "
     "configdir=<configuration directory>"
 );
 
@@ -71,6 +72,7 @@ static const char* const valid_modargs[] = {
     "dbus_policyd_name",
     "null_sink_name",
     "othermedia_preemption",
+    "route_sources_first",
     "configdir",
     NULL
 };
@@ -86,6 +88,7 @@ int pa__init(pa_module *m) {
     const char      *pdnam;
     const char      *nsnam;
     const char      *preempt;
+    bool             route_sources_first = false;
     const char      *cfgdir;
 
     pa_assert(m);
@@ -104,7 +107,11 @@ int pa__init(pa_module *m) {
     preempt = pa_modargs_get_value(ma, "othermedia_preemption", NULL);
     cfgdir  = pa_modargs_get_value(ma, "configdir", NULL);
 
-
+    if (pa_modargs_get_value_boolean(ma, "route_sources_first", &route_sources_first) < 0) {
+        pa_log("Failed to parse \"route_sources_first\" parameter.");
+        goto fail;
+    }
+
     u = pa_xnew0(struct userdata, 1);
     m->userdata = u;
     u->core     = m->core;
@@ -122,7 +129,7 @@ int pa__init(pa_module *m) {
     u->groups   = pa_policy_groupset_new(u);
     u->classify = pa_classify_new(u);
     u->context  = pa_policy_context_new(u);
-    u->dbusif   = pa_policy_dbusif_init(u, ifnam, mypath, pdpath, pdnam);
+    u->dbusif   = pa_policy_dbusif_init(u, ifnam, mypath, pdpath, pdnam, route_sources_first);
     u->shared   = pa_shared_data_get(u->core);
 
     if (u->scl == NULL      || u->ssnk == NULL     || u->ssrc == NULL ||