device-manager: Provide a way for clients to enable/disable role-based device-priority routing.

The routing logic itself does not yet exist, but the command currently will unload/load module-stream-restore as approriate.
(module-stream-restore would conflict with the role-based priority-routing).

src/modules/module-device-manager.c

@@ -79,6 +79,10 @@ struct userdata {
 
     pa_native_protocol *protocol;
     pa_idxset *subscribed;
+
+    pa_bool_t role_device_priority_routing;
+    pa_bool_t stream_restore_used;
+    pa_bool_t checked_stream_restore;
 };
 
 #define ENTRY_VERSION 1
@@ -93,6 +97,7 @@ enum {
     SUBCOMMAND_READ,
     SUBCOMMAND_WRITE,
     SUBCOMMAND_DELETE,
+    SUBCOMMAND_ROLE_DEVICE_PRIORITY_ROUTING,
     SUBCOMMAND_SUBSCRIBE,
     SUBCOMMAND_EVENT
 };
@@ -473,6 +478,57 @@ static int extension_cb(pa_native_protocol *p, pa_module *m, pa_native_connectio
 
       break;
 
+    case SUBCOMMAND_ROLE_DEVICE_PRIORITY_ROUTING:
+
+        while (!pa_tagstruct_eof(t)) {
+            pa_bool_t enable;
+            uint32_t sridx = PA_INVALID_INDEX;
+            uint32_t idx;
+            pa_module *module;
+
+            if (pa_tagstruct_get_boolean(t, &enable) < 0)
+                goto fail;
+
+            /* If this is the first run, check for stream restore module */
+            if (!u->checked_stream_restore) {
+                u->checked_stream_restore = TRUE;
+
+                for (module = pa_idxset_first(u->core->modules, &idx); module; module = pa_idxset_next(u->core->modules, &idx)) {
+                    if (strcmp(module->name, "module-stream-restore") == 0) {
+                        pa_log_debug("Detected module-stream-restore is currently in use");
+                        u->stream_restore_used = TRUE;
+                        sridx = module->index;
+                    }
+                }
+            }
+
+            u->role_device_priority_routing = enable;
+            if (enable) {
+                if (u->stream_restore_used) {
+                    if (PA_INVALID_INDEX == sridx) {
+                        /* As a shortcut on first load, we have sridx filled in, but otherwise we search for it. */
+                        for (module = pa_idxset_first(u->core->modules, &idx); module; module = pa_idxset_next(u->core->modules, &idx)) {
+                            if (strcmp(module->name, "module-stream-restore") == 0) {
+                                sridx = module->index;
+                            }
+                        }
+                    }
+                    if (PA_INVALID_INDEX != sridx) {
+                        pa_log_debug("Unloading module-stream-restore to enable role-based device-priority routing");
+                        pa_module_unload_request_by_index(u->core, sridx, TRUE);
+                    }
+                }
+            } else if (u->stream_restore_used) {
+                /* We want to reload module-stream-restore */
+                if (!pa_module_load(u->core, "module-stream-restore", ""))
+                    pa_log_warn("Failed to load module-stream-restore while disabling role-based device-priority routing");
+            }
+        }
+
+        trigger_save(u);
+
+        break;
+
     case SUBCOMMAND_SUBSCRIBE: {
 
       pa_bool_t enabled;

src/pulse/ext-device-manager.c

@@ -41,6 +41,7 @@ enum {
     SUBCOMMAND_READ,
     SUBCOMMAND_WRITE,
     SUBCOMMAND_DELETE,
+    SUBCOMMAND_ROLE_DEVICE_PRIORITY_ROUTING,
     SUBCOMMAND_SUBSCRIBE,
     SUBCOMMAND_EVENT
 };
@@ -289,6 +290,37 @@ fail:
     return NULL;
 }
 
+pa_operation *pa_ext_device_manager_enable_role_device_priority_routing(
+        pa_context *c,
+        int enable,
+        pa_context_success_cb_t cb,
+        void *userdata) {
+
+    uint32_t tag;
+    pa_operation *o = NULL;
+    pa_tagstruct *t = NULL;
+
+    pa_assert(c);
+    pa_assert(PA_REFCNT_VALUE(c) >= 1);
+
+    PA_CHECK_VALIDITY_RETURN_NULL(c, !pa_detect_fork(), PA_ERR_FORKED);
+    PA_CHECK_VALIDITY_RETURN_NULL(c, c->state == PA_CONTEXT_READY, PA_ERR_BADSTATE);
+    PA_CHECK_VALIDITY_RETURN_NULL(c, c->version >= 14, PA_ERR_NOTSUPPORTED);
+
+    o = pa_operation_new(c, NULL, (pa_operation_cb_t) cb, userdata);
+
+    t = pa_tagstruct_command(c, PA_COMMAND_EXTENSION, &tag);
+    pa_tagstruct_putu32(t, PA_INVALID_INDEX);
+    pa_tagstruct_puts(t, "module-device-manager");
+    pa_tagstruct_putu32(t, SUBCOMMAND_ROLE_DEVICE_PRIORITY_ROUTING);
+    pa_tagstruct_put_boolean(t, !!enable);
+
+    pa_pstream_send_tagstruct(c->pstream, t);
+    pa_pdispatch_register_reply(c->pdispatch, tag, DEFAULT_TIMEOUT, pa_context_simple_ack_callback, pa_operation_ref(o), (pa_free_cb_t) pa_operation_unref);
+
+    return o;
+}
+
 pa_operation *pa_ext_device_manager_subscribe(
         pa_context *c,
         int enable,

src/pulse/ext-device-manager.h

@@ -82,6 +82,13 @@ pa_operation *pa_ext_device_manager_delete(
         pa_context_success_cb_t cb,
         void *userdata);
 
+/** Subscribe to changes in the device database. \since 0.9.19 */
+pa_operation *pa_ext_device_manager_enable_role_device_priority_routing(
+        pa_context *c,
+        int enable,
+        pa_context_success_cb_t cb,
+        void *userdata);
+
 /** Subscribe to changes in the device database. \since 0.9.19 */
 pa_operation *pa_ext_device_manager_subscribe(
         pa_context *c,