scripts/policy-desktop: add move & follow settings handlers

src/scripts/policy-desktop/move-follow.lua

@@ -0,0 +1,68 @@
+-- WirePlumber
+--
+-- Copyright © 2022 Collabora Ltd.
+--
+-- SPDX-License-Identifier: MIT
+--
+-- Move & follow settings handlers. If the relevant settings are enabled,
+-- install hooks that will schedule a rescan of the graph when needed
+
+local config = require ("policy-config")
+local handles = {}
+
+function handleFollowSetting (enable)
+  if (not handles.follow_hook) and (enable == true) then
+    handles.follow_hook = SimpleEventHook {
+      name = "follow@policy-desktop",
+      type = "on-event",
+      priority = HookPriority.NORMAL,
+      interests = {
+        EventInterest {
+          Constraint { "event.type", "=", "metadata-changed" },
+          Constraint { "metadata.name", "=", "default" },
+          Constraint { "event.subject.key", "c", "default.audio.source",
+              "default.audio.sink", "default.video.source" },
+        },
+      },
+      execute = function (event)
+        local source = event:get_source ()
+        source:call ("schedule-rescan")
+      end
+    }
+    handles.follow_hook:register ()
+  elseif (handles.follow_hook) and (enable == false) then
+    handles.follow_hook:remove ()
+    handles.follow_hook = nil
+  end
+end
+
+function handleMoveSetting (enable)
+  if (not handles.move_hook) and (enable == true) then
+    handles.move_hook = SimpleEventHook {
+      name = "move@policy-desktop",
+      type = "on-event",
+      priority = HookPriority.NORMAL,
+      interests = {
+        EventInterest {
+          Constraint { "event.type", "=", "metadata-changed" },
+          Constraint { "metadata.name", "=", "default" },
+          Constraint { "event.subject.key", "c", "target.node", "target.object" },
+        },
+      },
+      execute = function (event)
+        local source = event:get_source ()
+        source:call ("schedule-rescan")
+      end
+    }
+    handles.move_hook:register()
+  elseif (handles.move_hook) and (enable == false) then
+    handles.move_hook:remove ()
+    handles.move_hook = nil
+  end
+end
+
+config:subscribe ("follow", handleFollowSetting)
+handleFollowSetting (config.follow)
+
+config:subscribe ("move", handleMoveSetting)
+handleMoveSetting (config.move)