scripts: use the event stack to handle virtual session items

This removes both the policy-virtual-client.lua and policy-virtual-device.lua
scripts, and creates a new linking/find-virtual-target.lua script to link
clients with virtual session items if one of them can be found. In addition to
this, this patch also ports the policy-virtual-client-links.lua into a new
scripts/rescan-virtual-links.lua to use the event stack. The idea is for the
scripts/link-target.lua to create all links but only activate non virtual links,
and for the scripts/rescan-virtual-links.lua to activate/deactivate virtual
links based on role priorities.

modules/module-si-audio-virtual.c

@@ -90,7 +90,8 @@ si_audio_virtual_configure (WpSessionItem * item, WpProperties *p)
   if (strstr (self->media_class, "Source") ||
       strstr (self->media_class, "Output"))
     self->direction = WP_DIRECTION_OUTPUT;
-  wp_properties_setf (si_props, "direction", "%u", self->direction);
+  wp_properties_set (si_props, "item.node.direction",
+      self->direction == WP_DIRECTION_OUTPUT ? "output" : "input");
 
   str = wp_properties_get (si_props, "role");
   if (str) {
@@ -109,6 +110,10 @@ si_audio_virtual_configure (WpSessionItem * item, WpProperties *p)
   str = wp_properties_get (si_props, "item.features.no-dsp");
   self->disable_dsp = str && pw_properties_parse_bool (str);
 
+  /* We always want virtual sources to autoconnect */
+  wp_properties_set (si_props, PW_KEY_NODE_AUTOCONNECT, "true");
+  wp_properties_set (si_props, "media.type", "Audio");
+
   wp_properties_set (si_props, "item.factory.name", SI_FACTORY_NAME);
   wp_session_item_set_properties (WP_SESSION_ITEM (self),
       g_steal_pointer (&si_props));
@@ -193,6 +198,21 @@ on_node_activate_done (WpObject * node, GAsyncResult * res,
             "si-audio-virtual: could not create si-audio-adapter"));
   }
 
+  /* Set node.id and node.name properties in this session item */
+  {
+    g_autoptr (WpProperties) si_props = wp_session_item_get_properties (
+        WP_SESSION_ITEM (self));
+    g_autoptr (WpProperties) new_props = wp_properties_new_empty ();
+    guint32 node_id = wp_proxy_get_bound_id (WP_PROXY (node));
+    wp_properties_setf (new_props, "node.id", "%u", node_id);
+    wp_properties_set (new_props, "node.name",
+        wp_pipewire_object_get_property (WP_PIPEWIRE_OBJECT (node),
+        PW_KEY_NODE_NAME));
+    wp_properties_update (si_props, new_props);
+    wp_session_item_set_properties (WP_SESSION_ITEM (self),
+        g_steal_pointer (&si_props));
+  }
+
   /* Forward adapter-ports-state-changed signal */
   g_signal_connect_object (self->adapter, "adapter-ports-state-changed",
       G_CALLBACK (on_adapter_port_state_changed), self, 0);
@@ -243,6 +263,7 @@ si_audio_virtual_enable_active (WpSessionItem *si, WpTransition *transition)
           PW_KEY_MEDIA_CLASS, media,
           PW_KEY_FACTORY_NAME, "support.null-audio-sink",
           PW_KEY_NODE_DESCRIPTION, desc,
+          PW_KEY_NODE_AUTOCONNECT, "true",
           "monitor.channel-volumes", "true",
           "wireplumber.is-virtual", "true",
           NULL));

src/config/wireplumber.conf

@@ -221,14 +221,16 @@ wireplumber.components = [
   { name = default-nodes/find-best-default-node.lua, type = script/lua, priority = 100 }
   { name = default-nodes/select-default-nodes.lua, type = script/lua, priority = 100 }
 
-  { name = linking/find-best-target.lua, type = script/lua, priority = 100 }
+  { name = linking/find-virtual-target.lua, type = script/lua, priority = 100 }
   { name = linking/find-defined-target.lua, type = script/lua, priority = 100 }
+  { name = linking/find-default-target.lua, type = script/lua, priority = 100 }
+  { name = linking/find-best-target.lua, type = script/lua, priority = 100 }
   { name = linking/link-target.lua, type = script/lua, priority = 100 }
   { name = linking/prepare-link.lua, type = script/lua, priority = 100 }
   { name = linking/filter-forward-format.lua, type = script/lua, priority = 100 }
-  { name = linking/find-default-target.lua, type = script/lua, priority = 100 }
   { name = linking/rescan.lua, type = script/lua, priority = 100 }
   { name = linking/move-follow.lua, type = script/lua, priority = 100 }
+  { name = linking/rescan-virtual-links.lua, type = script/lua, priority = 100 }
 
   { name = device/apply-routes.lua, type = script/lua, priority = 100 }
   { name = device/find-best-profile.lua, type = script/lua, priority = 100 }
@@ -243,6 +245,7 @@ wireplumber.components = [
   { name = client/access-default.lua, type = script/lua, priority = 100 }
 
   { name = node/create-item.lua, type = script/lua, priority = 100 }
+  { name = node/create-virtual-item.lua, type = script/lua, priority = 100 }
   { name = node/suspend-node.lua, type = script/lua, priority = 100 }
   { name = node/state-stream.lua, type = script/lua, priority = 100 }
 ]

src/scripts/lib/common-utils.lua

@@ -24,6 +24,12 @@ end
 
 function cutils.getTargetDirection (properties)
   local target_direction = nil
+
+  -- retrun same direction for si-audio-virtual session items
+  if properties ["item.factory.name"] == "si-audio-virtual" then
+    return properties ["item.node.direction"]
+  end
+
   if properties ["item.node.direction"] == "output" or
       (properties ["item.node.direction"] == "input" and
           cutils.parseBool (properties ["stream.capture.sink"])) then

src/scripts/lib/policy-utils.lua

@@ -134,8 +134,6 @@ function putils.canLink (properties, si_target)
     return false
   end
 
-  -- nodes must have opposite direction, or otherwise they must be both input
-  -- and the target must have a monitor (so the target will be used as a source)
   local function isMonitor(properties)
     return properties ["item.node.direction"] == "input" and
         parseBool (properties ["item.features.monitor"]) and
@@ -143,10 +141,20 @@ function putils.canLink (properties, si_target)
         properties ["item.factory.name"] == "si-audio-adapter"
   end
 
+  if properties ["item.factory.name"] == "si-audio-virtual" then
+    -- virtual nodes must have the same direction, unless the target is monitor
+    if properties ["item.node.direction"] ~= target_props ["item.node.direction"]
+        and not isMonitor (target_props) then
+      return false
+    end
+  else
+    -- nodes must have opposite direction, or otherwise they must be both input
+    -- and the target must have a monitor (so the target will be used as a source)
     if properties ["item.node.direction"] == target_props ["item.node.direction"]
         and not isMonitor (target_props) then
       return false
     end
+  end
 
   -- check link group
   local function canLinkGroupCheck(link_group, si_target, hops)
@@ -305,8 +313,6 @@ linkables_om:activate ()
 links_om = ObjectManager {
   Interest {
     type = "SiLink",
-    -- only handle links created by this policy
-    Constraint { "is.policy.item.link", "=", true },
   }
 }
 

src/scripts/linking/find-defined-target.lua

@@ -15,6 +15,7 @@ local config = require ("policy-config")
 
 SimpleEventHook {
   name = "linking/find-defined-target",
+  after = "linking/find-virtual-target",
   interests = {
     EventInterest {
       Constraint { "event.type", "=", "select-target" },

src/scripts/linking/find-virtual-target.lua

@@ -0,0 +1,124 @@
+-- WirePlumber
+--
+-- Copyright © 2022 Collabora Ltd.
+--
+-- SPDX-License-Identifier: MIT
+--
+-- Select the virtual target based on roles
+
+local putils = require ("policy-utils")
+
+local defaults = {}
+defaults.roles = Json.Object {}
+
+local config = {}
+config.roles = Conf.get_section (
+    "virtual-item-roles", defaults.roles):parse ()
+
+function findRole(role, tmc)
+  if role and not config.roles[role] then
+    -- find the role with matching alias
+    for r, p in pairs(config.roles) do
+      -- default media class can be overridden in the role config data
+      mc = p["media.class"] or "Audio/Sink"
+      if (type(p.alias) == "table" and tmc == mc) then
+        for i = 1, #(p.alias), 1 do
+          if role == p.alias[i] then
+            return r
+          end
+        end
+      end
+    end
+
+    -- otherwise get the lowest priority role
+    local lowest_priority_p = nil
+    local lowest_priority_r = nil
+    for r, p in pairs(config.roles) do
+      mc = p["media.class"] or "Audio/Sink"
+      if tmc == mc and (lowest_priority_p == nil or
+          p.priority < lowest_priority_p.priority) then
+        lowest_priority_p = p
+        lowest_priority_r = r
+      end
+    end
+    return lowest_priority_r
+  end
+  return role
+end
+
+SimpleEventHook {
+  name = "linking/find-virtual-target",
+  interests = {
+    EventInterest {
+      Constraint { "event.type", "=", "select-target" },
+    },
+  },
+  execute = function (event)
+    local source, om, si, si_props, si_flags, target =
+        putils:unwrap_find_target_event (event)
+    local target_class_assoc = {
+      ["Stream/Input/Audio"] = "Audio/Source",
+      ["Stream/Output/Audio"] = "Audio/Sink",
+      ["Stream/Input/Video"] = "Video/Source",
+    }
+    local node = si:get_associated_proxy ("node")
+    local highest_priority = -1
+    local target = nil
+    local role = node.properties["media.role"] or "Default"
+
+    -- bypass the hook if the target is already picked up
+    if target then
+      return
+    end
+
+    -- dont use virtual target for any si-audio-virtual
+    if si_props ["item.factory.name"] == "si-audio-virtual" then
+      return
+    end
+
+    Log.info (si, string.format ("handling item: %s (%s)",
+        tostring (si_props ["node.name"]), tostring (si_props ["node.id"])))
+
+    -- get target media class
+    local target_media_class = target_class_assoc[si_props ["media.class"]]
+    if not target_media_class then
+      Log.info (si, "target media class not found")
+      return
+    end
+
+    -- find highest priority virtual by role
+    local media_role = findRole (role, target_media_class)
+    if media_role == nil then
+      Log.info (si, "media role not found")
+      return
+    end
+
+    for si_virtual in om:iterate {
+      Constraint { "role", "=", media_role, type = "pw-global" },
+      Constraint { "media.class", "=", target_media_class, type = "pw-global" },
+      Constraint { "item.factory.name", "=", "si-audio-virtual", type = "pw-global" },
+    } do
+      local priority = tonumber(si_virtual.properties["priority"])
+      if priority > highest_priority then
+        highest_priority = priority
+        target = si_virtual
+      end
+    end
+
+    local can_passthrough, passthrough_compatible
+    if target then
+      passthrough_compatible, can_passthrough =
+      putils.checkPassthroughCompatibility (si, target)
+
+      if not passthrough_compatible then
+        target = nil
+      end
+    end
+
+    -- set target
+    if target ~= nil then
+      si_flags.can_passthrough = can_passthrough
+      event:set_data ("target", target)
+    end
+  end
+}:register ()

src/scripts/linking/link-target.lua

@@ -20,7 +20,7 @@ AsyncEventHook {
   },
   steps = {
     start = {
-      next = "link_activated",
+      next = "none",
       execute = function (event, transition)
         local source, om, si, si_props, si_flags, target =
             putils:unwrap_find_target_event (event)
@@ -53,6 +53,17 @@ AsyncEventHook {
               .. tostring (si_link))
         end
 
+        if si_props ["item.factory.name"] == "si-audio-virtual" then
+          if si_props ["item.node.direction"] == "output" then
+            -- playback
+            out_item = target
+            in_item = si
+          else
+            -- capture
+            in_item = target
+            out_item = si
+          end
+        else
           if si_props ["item.node.direction"] == "output" then
             -- playback
             out_item = si
@@ -62,12 +73,18 @@ AsyncEventHook {
             in_item = si
             out_item = target
           end
+        end
+
+        local is_virtual_client_link = target_props ["item.factory.name"] == "si-audio-virtual"
 
         Log.info (si,
-          string.format ("link %s <-> %s passive:%s, passthrough:%s, exclusive:%s",
+          string.format ("link %s <-> %s passive:%s, passthrough:%s, exclusive:%s, virtual-client:%s",
             tostring (si_props ["node.name"]),
             tostring (target_props ["node.name"]),
-            tostring (passive), tostring (passthrough), tostring (exclusive)))
+            tostring (passive),
+            tostring (passthrough),
+            tostring (exclusive),
+            tostring (is_virtual_client_link)))
 
         -- create and configure link
         si_link = SessionItem ("si-standard-link")
@@ -79,7 +96,11 @@ AsyncEventHook {
           ["exclusive"] = exclusive,
           ["out.item.port.context"] = "output",
           ["in.item.port.context"] = "input",
-          ["is.policy.item.link"] = true,
+          ["media.role"] = target_props["role"],
+          ["target.media.class"] = target_props["media.class"],
+          ["is.virtual.client.link"] = is_virtual_client_link,
+          ["main.item.id"] = si.id,
+          ["target.item.id"] = target.id,
         } then
           transition:return_error ("failed to configure si-standard-link "
             .. tostring (si_link))
@@ -119,7 +140,12 @@ AsyncEventHook {
         end
         si_link:register ()
 
-        -- activate
+        Log.info (si_link, "registered virtual si-standard-link between "
+                .. tostring (si).." and ".. tostring(target))
+
+        -- only activate non virtual links because virtual links activation is
+        -- handled by rescan-virtual-links.lua
+        if not is_virtual_client_link then
           si_link:activate (Feature.SessionItem.ACTIVE, function (l, e)
             if e then
               transition:return_error ("failed to activate si-standard-link: "
@@ -130,33 +156,21 @@ AsyncEventHook {
               l:remove ()
             else
               si_flags.si_link = si_link
+              si_flags.failed_peer_id = nil
+              if si_flags.peer_id == nil then
+                si_flags.peer_id = target.id
+              end
+              si_flags.failed_count = 0
+
+              Log.info (si_link, "activated si-standard-link between "
+                .. tostring (si).." and ".. tostring(target))
+
               transition:advance ()
             end
           end)
-      end,
+        else
-    },
-    link_activated = {
-      next = "none",
-      execute = function (event, transition)
-        local source, om, si, si_props, si_flags, target =
-            putils:unwrap_find_target_event (event)
-        if not target then
-          -- bypass the hook, nothing to link to.
           transition:advance ()
-          return
         end
-
-        if si_flags ~= nil then
-          si_flags.failed_peer_id = nil
-          if si_flags.peer_id == nil then
-            si_flags.peer_id = si_target.id
-          end
-          si_flags.failed_count = 0
-        end
-        Log.info (si_flags.si_link, "activated si-standard-link between "
-            .. tostring (si).." and "..tostring(si_target))
-
-        transition:advance ()
       end,
     },
   },

src/scripts/linking/rescan-virtual-links.lua

@@ -0,0 +1,254 @@
+-- WirePlumber
+--
+-- Copyright © 2023 Collabora Ltd.
+--    @author Julian Bouzas <george.kiagiadakis@collabora.com>
+--
+-- SPDX-License-Identifier: MIT
+
+local putils = require ("policy-utils")
+
+local defaults = {}
+defaults.duck_level = 0.3
+defaults.roles = Json.Object {}
+
+local config = {}
+config.duck_level = Conf.get_value_float ("wireplumber.settings",
+    "policy.default.duck-level", defaults.duck_level)
+config.roles = Conf.get_section (
+    "virtual-item-roles", defaults.roles):parse ()
+
+-- enable ducking if mixer-api is loaded
+mixer_api = Plugin.find("mixer-api")
+
+function findRole (role)
+  if role and not config.roles[role] then
+    for r, p in pairs(config.roles) do
+      if type(p.alias) == "table" then
+        for i = 1, #(p.alias), 1 do
+          if role == p.alias[i] then
+            return r
+          end
+        end
+      end
+    end
+  end
+  return role
+end
+
+function getRolePriority (role)
+  local r = role and config.roles[role] or nil
+  return r and r.priority or 0
+end
+
+function getAction (dominant_role, other_role)
+  -- default to "mix" if the role is not configured
+  if not dominant_role or not config.roles[dominant_role] then
+    return "mix"
+  end
+
+  local role_config = config.roles[dominant_role]
+  return role_config["action." .. other_role]
+      or role_config["action.default"]
+      or "mix"
+end
+
+function restoreVolume (om, role, media_class)
+  if not mixer_api then return end
+
+  local si_v = om:lookup {
+    type = "SiLinkable",
+    Constraint { "item.factory.name", "=", "si-audio-virtual", type = "pw-global" },
+    Constraint { "media.role", "=", role, type = "pw" },
+    Constraint { "media.class", "=", media_class, type = "pw" },
+  }
+
+  if si_v then
+    local n = si_v:get_associated_proxy ("node")
+    if n then
+      Log.debug(si_v, "restore role " .. role)
+      mixer_api:call("set-volume", n["bound-id"], {
+        monitorVolume = 1.0,
+      })
+    end
+  end
+end
+
+function duckVolume (om, role, media_class)
+  if not mixer_api then return end
+
+  local si_v = om:lookup {
+    type = "SiLinkable",
+    Constraint { "item.factory.name", "=", "si-audio-virtual", type = "pw-global" },
+    Constraint { "media.role", "=", role, type = "pw" },
+    Constraint { "media.class", "=", media_class, type = "pw" },
+  }
+
+  if si_v then
+    local n = si_v:get_associated_proxy ("node")
+    if n then
+      Log.debug(si_v, "duck role " .. role)
+      mixer_api:call("set-volume", n["bound-id"], {
+        monitorVolume = config.duck_level,
+      })
+    end
+  end
+end
+
+function getSuspendPlaybackFromMetadata (om)
+  local suspend = false
+  local metadata = om:lookup {
+    type = "metadata",
+    Constraint { "metadata.name", "=", "default" },
+  }
+  if metadata then
+    local value = metadata:find(0, "suspend.playback")
+    if value then
+      suspend = value == "1" and true or false
+    end
+  end
+  return suspend
+end
+
+AsyncEventHook {
+  name = "linking/rescan-virtual-links",
+  interests = {
+    EventInterest {
+      -- on virtual client link added and removed
+      Constraint { "event.type", "c", "session-item-added", "session-item-removed" },
+      Constraint { "event.session-item.interface", "=", "link" },
+      Constraint { "is.virtual.client.link", "=", true },
+    },
+    EventInterest {
+      -- on default metadata suspend.playback changed
+      Constraint { "event.type", "=", "metadata-changed" },
+      Constraint { "metadata.name", "=", "default" },
+      Constraint { "event.subject.key", "=", "suspend.playback" },
+    }
+  },
+  steps = {
+    start = {
+      next = "none",
+      execute = function (event, transition)
+        local source = event:get_source ()
+        local om = source:call ("get-object-manager", "session-item")
+        local metadata_om = source:call ("get-object-manager", "metadata")
+        local suspend = getSuspendPlaybackFromMetadata (metadata_om)
+        local pending_activations = 0
+        local links = {
+          ["Audio/Source"] = {},
+          ["Audio/Sink"] = {},
+          ["Video/Source"] = {},
+        }
+
+        -- gather info about links
+        Log.info ("Rescanning virtual si-standard-link links...")
+        for silink in om:iterate {
+            type = "SiLink",
+            Constraint { "is.virtual.client.link", "=", true },
+          } do
+
+          -- deactivate all links if suspend playback metadata is present
+          if suspend then
+            silink:deactivate (Feature.SessionItem.ACTIVE)
+          end
+
+          local props = silink.properties
+          local role = props["media.role"]
+          local target_class = props["target.media.class"]
+          local plugged = props["item.plugged.usec"]
+          local active = ((silink:get_active_features() & Feature.SessionItem.ACTIVE) ~= 0)
+          if links[target_class] then
+            table.insert(links[target_class], {
+              silink = silink,
+              role = findRole (role),
+              active = active,
+              priority = getRolePriority (role),
+              plugged = plugged and tonumber(plugged) or 0
+            })
+          end
+        end
+
+        local function onVirtualLinkActivated (l, e)
+          local si_id = tonumber (l.properties ["main.item.id"])
+          local target_id = tonumber (l.properties ["target.item.id"])
+          local si_flags = putils:get_flags (si_id)
+
+          if e then
+            Log.warning (l, "failed to activate virtual si-standard-link: " .. e)
+            if si_flags ~= nil then
+              si_flags.peer_id = nil
+            end
+            l:remove ()
+          else
+            Log.info (l, "virtual si-standard-link activated successfully")
+            si_flags.si_link = l
+            si_flags.failed_peer_id = nil
+            if si_flags.peer_id == nil then
+              si_flags.peer_id = target_id
+            end
+            si_flags.failed_count = 0
+          end
+
+          -- advance only when all pending activations are completed
+          pending_activations = pending_activations - 1
+          if pending_activations <= 0 then
+            Log.info ("All virtual si-standard-links activated")
+            transition:advance ()
+          end
+        end
+
+        local function compareLinks(l1, l2)
+          return (l1.priority > l2.priority) or
+              ((l1.priority == l2.priority) and (l1.plugged > l2.plugged))
+        end
+
+        for media_class, v in pairs(links) do
+          -- sort on priority and stream creation time
+          table.sort(v, compareLinks)
+
+          -- apply actions
+          local first_link = v[1]
+          if first_link then
+            for i = 2, #v, 1 do
+              local action = getAction(first_link.role, v[i].role)
+              if action == "cork" then
+                if v[i].active then
+                  v[i].silink:deactivate(Feature.SessionItem.ACTIVE)
+                end
+              elseif action == "mix" then
+                if not v[i].active and not suspend then
+                  pending_activations = pending_activations + 1
+                  v[i].silink:activate (Feature.SessionItem.ACTIVE,
+                      onVirtualLinkActivated)
+                end
+                restoreVolume(om, v[i].role, media_class)
+              elseif action == "duck" then
+                if not v[i].active and not suspend then
+                  pending_activations = pending_activations + 1
+                  v[i].silink:activate (Feature.SessionItem.ACTIVE,
+                      onVirtualLinkActivated)
+                end
+                duckVolume (om, v[i].role, media_class)
+              else
+                Log.warning("Unknown action: " .. action)
+              end
+            end
+
+            if not first_link.active and not suspend then
+              pending_activations = pending_activations + 1
+              first_link.silink:activate(Feature.SessionItem.ACTIVE,
+                 onVirtualLinkActivated)
+            end
+            restoreVolume (om, first_link.role, media_class)
+          end
+        end
+
+        -- just advance transition if no pending activations are needed
+        if pending_activations <= 0 then
+          Log.info ("All virtual si-standard-links rescanned")
+          transition:advance ()
+        end
+      end,
+    },
+  },
+}:register ()

src/scripts/linking/rescan.lua

@@ -14,16 +14,17 @@ local putils = require ("policy-utils")
 local cutils = require ("common-utils")
 
 function checkLinkable (si, om, handle_nonstreams)
-  -- only handle stream session items
   local si_props = si.properties
-  if not si_props or (si_props ["item.node.type"] ~= "stream"
+
-      and not handle_nonstreams) then
+  -- Always handle si-audio-virtual session items
-    return false
+  if si_props ["item.factory.name"] == "si-audio-virtual" then
+    return true, si_props
   end
 
-  -- Determine if we can handle item by this policy
+  -- For the rest of them, only handle stream session items
-  if si_props ["item.factory.name"] == "si-audio-virtual" then
+  if not si_props or (si_props ["item.node.type"] ~= "stream"
-    return false
+      and not handle_nonstreams) then
+    return false, si_props
   end
 
   return true, si_props
@@ -116,7 +117,7 @@ SimpleEventHook {
     EventInterest {
       Constraint { "event.type", "c", "session-item-added", "session-item-removed" },
       Constraint { "event.session-item.interface", "=", "linkable" },
-      Constraint { "item.factory.name", "c", "si-audio-adapter", "si-node" },
+      Constraint { "item.factory.name", "c", "si-audio-adapter", "si-node", "si-audio-virtual" },
     },
     -- on device Routes changed
     EventInterest {

src/scripts/policy-virtual-client-links.lua

@@ -1,232 +0,0 @@
--- WirePlumber
---
--- Copyright © 2021 Collabora Ltd.
---    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
---
--- SPDX-License-Identifier: MIT
-
-local defaults = {}
-defaults.duck_level = 0.3
-defaults.roles = Json.Object {}
-
-local config = {}
-config.duck_level = Conf.get_value_float ("wireplumber.settings",
-    "policy.default.duck-level", defaults.duck_level)
-config.roles = Conf.get_section (
-    "virtual-item-roles", defaults.roles):parse ()
-
-function findRole(role)
-  if role and not config.roles[role] then
-    for r, p in pairs(config.roles) do
-      if type(p.alias) == "table" then
-        for i = 1, #(p.alias), 1 do
-          if role == p.alias[i] then
-            return r
-          end
-        end
-      end
-    end
-  end
-  return role
-end
-
-function priorityForRole(role)
-  local r = role and config.roles[role] or nil
-  return r and r.priority or 0
-end
-
-function getAction(dominant_role, other_role)
-  -- default to "mix" if the role is not configured
-  if not dominant_role or not config.roles[dominant_role] then
-    return "mix"
-  end
-
-  local role_config = config.roles[dominant_role]
-  return role_config["action." .. other_role]
-      or role_config["action.default"]
-      or "mix"
-end
-
-function restoreVolume(role, media_class)
-  if not mixer_api then return end
-
-  local si_v = virtuals_om:lookup {
-    Constraint { "media.role", "=", role, type = "pw" },
-    Constraint { "media.class", "=", media_class, type = "pw" },
-  }
-
-  if si_v then
-    local n = si_v:get_associated_proxy ("node")
-    if n then
-      Log.debug(si_v, "restore role " .. role)
-      mixer_api:call("set-volume", n["bound-id"], {
-        monitorVolume = 1.0,
-      })
-    end
-  end
-end
-
-function duck(role, media_class)
-  if not mixer_api then return end
-
-  local si_v = virtuals_om:lookup {
-    Constraint { "media.role", "=", role, type = "pw" },
-    Constraint { "media.class", "=", media_class, type = "pw" },
-  }
-
-  if si_v then
-    local n = si_v:get_associated_proxy ("node")
-    if n then
-      Log.debug(si_v, "duck role " .. role)
-      mixer_api:call("set-volume", n["bound-id"], {
-        monitorVolume = config.duck_level,
-      })
-    end
-  end
-end
-
-function getSuspendPlaybackMetadata ()
-  local suspend = false
-  local metadata = metadata_om:lookup()
-  if metadata then
-    local value = metadata:find(0, "suspend.playback")
-    if value then
-      suspend = value == "1" and true or false
-    end
-  end
-  return suspend
-end
-
-function rescan()
-  local links = {
-    ["Audio/Source"] = {},
-    ["Audio/Sink"] = {},
-    ["Video/Source"] = {},
-  }
-
-  Log.info("Rescan virtual links")
-
-  -- deactivate all links if suspend playback metadata is present
-  local suspend = getSuspendPlaybackMetadata()
-  for silink in silinks_om:iterate() do
-    if suspend then
-      silink:deactivate(Feature.SessionItem.ACTIVE)
-    end
-  end
-
-  -- gather info about links
-  for silink in silinks_om:iterate() do
-    local props = silink.properties
-    local role = props["media.role"]
-    local target_class = props["target.media.class"]
-    local plugged = props["item.plugged.usec"]
-    local active =
-      ((silink:get_active_features() & Feature.SessionItem.ACTIVE) ~= 0)
-    if links[target_class] then
-      table.insert(links[target_class], {
-        silink = silink,
-        role = findRole(role),
-        active = active,
-        priority = priorityForRole(role),
-        plugged = plugged and tonumber(plugged) or 0
-      })
-    end
-  end
-
-  local function compareLinks(l1, l2)
-    return (l1.priority > l2.priority) or
-        ((l1.priority == l2.priority) and (l1.plugged > l2.plugged))
-  end
-
-  for media_class, v in pairs(links) do
-    -- sort on priority and stream creation time
-    table.sort(v, compareLinks)
-
-    -- apply actions
-    local first_link = v[1]
-    if first_link then
-      for i = 2, #v, 1 do
-        local action = getAction(first_link.role, v[i].role)
-        if action == "cork" then
-          if v[i].active then
-            v[i].silink:deactivate(Feature.SessionItem.ACTIVE)
-          end
-        elseif action == "mix" then
-          if not v[i].active and not suspend then
-            v[i].silink:activate(Feature.SessionItem.ACTIVE, pendingOperation())
-          end
-          restoreVolume(v[i].role, media_class)
-        elseif action == "duck" then
-          if not v[i].active and not suspend then
-            v[i].silink:activate(Feature.SessionItem.ACTIVE, pendingOperation())
-          end
-          duck(v[i].role, media_class)
-        else
-          Log.warning("Unknown action: " .. action)
-        end
-      end
-
-      if not first_link.active and not suspend then
-        first_link.silink:activate(Feature.SessionItem.ACTIVE, pendingOperation())
-      end
-      restoreVolume(first_link.role, media_class)
-    end
-  end
-end
-
-pending_ops = 0
-pending_rescan = false
-
-function pendingOperation()
-  pending_ops = pending_ops + 1
-  return function()
-    pending_ops = pending_ops - 1
-    if pending_ops == 0 and pending_rescan then
-      pending_rescan = false
-      rescan()
-    end
-  end
-end
-
-function maybeRescan()
-  if pending_ops == 0 then
-    rescan()
-  else
-    pending_rescan = true
-  end
-end
-
-silinks_om = ObjectManager {
-  Interest {
-    type = "SiLink",
-    Constraint { "is.policy.virtual.client.link", "=", true },
-  },
-}
-silinks_om:connect("objects-changed", maybeRescan)
-silinks_om:activate()
-
--- enable ducking if mixer-api is loaded
-mixer_api = Plugin.find("mixer-api")
-if mixer_api then
-  virtuals_om = ObjectManager { Interest { type = "SiLinkable",
-    Constraint {
-      "item.factory.name", "=", "si-audio-virtual", type = "pw-global" },
-    }
-  }
-  virtuals_om:activate()
-end
-
-metadata_om = ObjectManager {
-  Interest {
-    type = "metadata",
-    Constraint { "metadata.name", "=", "default" },
-  }
-}
-metadata_om:connect("object-added", function (om, metadata)
-  metadata:connect("changed", function (m, subject, key, t, value)
-    if key == "suspend.playback" then
-      maybeRescan()
-    end
-  end)
-end)
-metadata_om:activate()

src/scripts/policy-virtual-client.lua

@@ -1,268 +0,0 @@
--- WirePlumber
---
--- Copyright © 2021 Collabora Ltd.
---    @author Julian Bouzas <julian.bouzas@collabora.com>
---
--- SPDX-License-Identifier: MIT
-
--- Receive script arguments from config.lua
-
-local defaults = {}
-defaults.roles = Json.Object {}
-
-local config = {}
-config.roles = Conf.get_section (
-    "virtual-item-roles", defaults.roles):parse ()
-
-local self = {}
-self.scanning = false
-self.pending_rescan = false
-
-function rescan ()
-  for si in linkables_om:iterate() do
-    handleLinkable (si)
-  end
-end
-
-function scheduleRescan ()
-  if self.scanning then
-    self.pending_rescan = true
-    return
-  end
-
-  self.scanning = true
-  rescan ()
-  self.scanning = false
-
-  if self.pending_rescan then
-    self.pending_rescan = false
-    Core.sync(function ()
-      scheduleRescan ()
-    end)
-  end
-end
-
-function findRole(role, tmc)
-  if role and not config.roles[role] then
-    -- find the role with matching alias
-    for r, p in pairs(config.roles) do
-      -- default media class can be overridden in the role config data
-      mc = p["media.class"] or "Audio/Sink"
-      if (type(p.alias) == "table" and tmc == mc) then
-        for i = 1, #(p.alias), 1 do
-          if role == p.alias[i] then
-            return r
-          end
-        end
-      end
-    end
-
-    -- otherwise get the lowest priority role
-    local lowest_priority_p = nil
-    local lowest_priority_r = nil
-    for r, p in pairs(config.roles) do
-      mc = p["media.class"] or "Audio/Sink"
-      if tmc == mc and (lowest_priority_p == nil or
-          p.priority < lowest_priority_p.priority) then
-        lowest_priority_p = p
-        lowest_priority_r = r
-      end
-    end
-    return lowest_priority_r
-  end
-  return role
-end
-
-function findTargetVirtual (node, media_class, role)
-  local target_class_assoc = {
-    ["Stream/Input/Audio"] = "Audio/Source",
-    ["Stream/Output/Audio"] = "Audio/Sink",
-    ["Stream/Input/Video"] = "Video/Source",
-  }
-  local media_role = nil
-  local highest_priority = -1
-  local target = nil
-
-  -- get target media class
-  local target_media_class = target_class_assoc[media_class]
-  if not target_media_class then
-    return nil
-  end
-
-  -- find highest priority virtual by role
-  media_role = findRole(role, target_media_class)
-  for si_target_ep in virtuals_om:iterate {
-    Constraint { "role", "=", media_role, type = "pw-global" },
-    Constraint { "media.class", "=", target_media_class, type = "pw-global" },
-  } do
-    local priority = tonumber(si_target_ep.properties["priority"])
-    if priority > highest_priority then
-      highest_priority = priority
-      target = si_target_ep
-    end
-  end
-
-  return target
-end
-
-function createLink (si, si_target_ep)
-  local out_item = nil
-  local in_item = nil
-  local si_props = si.properties
-  local target_ep_props = si_target_ep.properties
-
-  if si_props["item.node.direction"] == "output" then
-    -- playback
-    out_item = si
-    in_item = si_target_ep
-  else
-    -- capture
-    out_item = si_target_ep
-    in_item = si
-  end
-
-  Log.info (string.format("link %s <-> %s",
-      tostring(si_props["node.name"]),
-      tostring(target_ep_props["name"])))
-
-  -- create and configure link
-  local si_link = SessionItem ( "si-standard-link" )
-  if not si_link:configure {
-    ["out.item"] = out_item,
-    ["in.item"] = in_item,
-    ["out.item.port.context"] = "output",
-    ["in.item.port.context"] = "input",
-    ["is.policy.virtual.client.link"] = true,
-    ["media.role"] = target_ep_props["role"],
-    ["target.media.class"] = target_ep_props["media.class"],
-    ["item.plugged.usec"] = si_props["item.plugged.usec"],
-  } then
-    Log.warning (si_link, "failed to configure si-standard-link")
-    return
-  end
-
-  -- register
-  si_link:register()
-end
-
-function checkLinkable (si)
-  -- only handle session items that has a node associated proxy
-  local node = si:get_associated_proxy ("node")
-  if not node or not node.properties then
-    return false
-  end
-
-  -- only handle stream session items
-  local media_class = node.properties["media.class"]
-  if not media_class or not string.find (media_class, "Stream") then
-    return false
-  end
-
-  -- Determine if we can handle item by this policy
-  if virtuals_om:get_n_objects () == 0 then
-    Log.debug (si, "item won't be handled by this policy")
-    return false
-  end
-
-  return true
-end
-
-function handleLinkable (si)
-  if not checkLinkable (si) then
-    return
-  end
-
-  local node = si:get_associated_proxy ("node")
-  local media_class = node.properties["media.class"] or ""
-  local media_role = node.properties["media.role"] or "Default"
-  Log.info (si, "handling item " .. tostring(node.properties["node.name"]) ..
-      " with role " .. media_role)
-
-  -- find proper target virtual
-  local si_target_ep = findTargetVirtual (node, media_class, media_role)
-  if not si_target_ep then
-    Log.info (si, "... target virtual not found")
-    return
-  end
-
-  -- Check if item is linked to proper target, otherwise re-link
-  for link in links_om:iterate() do
-    local out_id = tonumber(link.properties["out.item.id"])
-    local in_id = tonumber(link.properties["in.item.id"])
-    if out_id == si.id or in_id == si.id then
-      local is_out = out_id == si.id and true or false
-      for peer_ep in virtuals_om:iterate() do
-        if peer_ep.id == (is_out and in_id or out_id) then
-
-          if peer_ep.id == si_target_ep.id then
-            Log.info (si, "... already linked to proper target virtual")
-            return
-          end
-
-          -- remove old link if active, otherwise schedule rescan
-          if ((link:get_active_features() & Feature.SessionItem.ACTIVE) ~= 0) then
-            link:remove ()
-            Log.info (si, "... moving to new target")
-          else
-            scheduleRescan ()
-            Log.info (si, "... scheduled rescan")
-            return
-          end
-
-        end
-      end
-    end
-  end
-
-  -- create new link
-  createLink (si, si_target_ep)
-end
-
-function unhandleLinkable (si)
-  if not checkLinkable (si) then
-    return
-  end
-
-  local node = si:get_associated_proxy ("node")
-  Log.info (si, "unhandling item " .. tostring(node.properties["node.name"]))
-
-  -- remove any links associated with this item
-  for silink in links_om:iterate() do
-    local out_id = tonumber (silink.properties["out.item.id"])
-    local in_id = tonumber (silink.properties["in.item.id"])
-    if out_id == si.id or in_id == si.id then
-      silink:remove ()
-      Log.info (silink, "... link removed")
-    end
-  end
-end
-
-virtuals_om = ObjectManager { Interest { type = "SiLinkable",
-  Constraint {
-    "item.factory.name", "=", "si-audio-virtual", type = "pw-global" },
-  }
-}
-linkables_om = ObjectManager { Interest { type = "SiLinkable",
-  -- only handle si-audio-adapter and si-node
-  Constraint {
-    "item.factory.name", "=", "si-audio-adapter", type = "pw-global" },
-  Constraint {
-    "active-features", "!", 0, type = "gobject" },
-  }
-}
-links_om = ObjectManager { Interest { type = "SiLink",
-  -- only handle links created by this policy
-  Constraint { "is.policy.virtual.client.link", "=", true, type = "pw-global" },
-} }
-
-linkables_om:connect("objects-changed", function (om)
-  scheduleRescan ()
-end)
-
-linkables_om:connect("object-removed", function (om, si)
-  unhandleLinkable (si)
-end)
-
-virtuals_om:activate()
-linkables_om:activate()
-links_om:activate()

src/scripts/policy-virtual-device.lua

@@ -1,238 +0,0 @@
--- WirePlumber
---
--- Copyright © 2021 Collabora Ltd.
---    @author Julian Bouzas <julian.bouzas@collabora.com>
---
--- SPDX-License-Identifier: MIT
-
-local defaults = {}
-defaults.follow = true
-
-local config = {}
-config.follow = Conf.get_value_boolean ("wireplumber.settings",
-    "policy.default.follow", defaults.follow)
-
-local self = {}
-self.scanning = false
-self.pending_rescan = false
-
-function rescan ()
-  -- check virtuals and register new links
-  for si_v in virtuals_om:iterate() do
-    handleVirtual (si_v)
-  end
-end
-
-function scheduleRescan ()
-  if self.scanning then
-    self.pending_rescan = true
-    return
-  end
-
-  self.scanning = true
-  rescan ()
-  self.scanning = false
-
-  if self.pending_rescan then
-    self.pending_rescan = false
-    Core.sync(function ()
-      scheduleRescan ()
-    end)
-  end
-end
-
-function findTargetByDefaultNode (target_media_class)
-  local def_id = default_nodes:call("get-default-node", target_media_class)
-  if def_id ~= Id.INVALID then
-    for si_target in linkables_om:iterate() do
-      local target_node = si_target:get_associated_proxy ("node")
-      if target_node["bound-id"] == def_id then
-        return si_target
-      end
-    end
-  end
-  return nil
-end
-
-function findTargetByFirstAvailable (target_media_class)
-  for si_target in linkables_om:iterate() do
-    local target_node = si_target:get_associated_proxy ("node")
-    if target_node.properties["media.class"] == target_media_class then
-      return si_target
-    end
-  end
-  return nil
-end
-
-function findUndefinedTarget (si_ep)
-  local media_class = si_ep.properties["media.class"]
-  local target_class_assoc = {
-    ["Audio/Source"] = "Audio/Source",
-    ["Audio/Sink"] = "Audio/Sink",
-    ["Video/Source"] = "Video/Source",
-  }
-  local target_media_class = target_class_assoc[media_class]
-  if not target_media_class then
-    return nil
-  end
-
-  local si_target = findTargetByDefaultNode (target_media_class)
-  if not si_target then
-    si_target = findTargetByFirstAvailable (target_media_class)
-  end
-  return si_target
-end
-
-function createLink (si_ep, si_target)
-  local out_item = nil
-  local in_item = nil
-  local ep_props = si_ep.properties
-  local target_props = si_target.properties
-
-  if target_props["item.node.direction"] == "input" then
-    -- playback
-    out_item = si_ep
-    in_item = si_target
-  else
-    -- capture
-    in_item = si_ep
-    out_item = si_target
-  end
-
-  Log.info (string.format("link %s <-> %s",
-      ep_props["name"],
-      target_props["node.name"]))
-
-  -- create and configure link
-  local si_link = SessionItem ( "si-standard-link" )
-  if not si_link:configure {
-    ["out.item"] = out_item,
-    ["in.item"] = in_item,
-    ["out.item.port.context"] = "output",
-    ["in.item.port.context"] = "input",
-    ["passive"] = true,
-    ["is.policy.virtual.device.link"] = true,
-  } then
-    Log.warning (si_link, "failed to configure si-standard-link")
-    return
-  end
-
-  -- register
-  si_link:register ()
-
-  -- activate
-  si_link:activate (Feature.SessionItem.ACTIVE, function (l, e)
-    if e then
-      Log.warning (l, "failed to activate si-standard-link: " .. tostring(e))
-      l:remove ()
-    else
-      Log.info (l, "activated si-standard-link")
-    end
-  end)
-end
-
-function handleVirtual (si_ep)
-  Log.info (si_ep, "handling virtual " .. si_ep.properties["name"])
-
-  -- find proper target item
-  local si_target = findUndefinedTarget (si_ep)
-  if not si_target then
-    Log.info (si_ep, "... target item not found")
-    return
-  end
-
-  -- Check if item is linked to proper target, otherwise re-link
-  for link in links_om:iterate() do
-    local out_id = tonumber(link.properties["out.item.id"])
-    local in_id = tonumber(link.properties["in.item.id"])
-    if out_id == si_ep.id or in_id == si_ep.id then
-      local is_out = out_id == si_ep.id and true or false
-      for peer in linkables_om:iterate() do
-        if peer.id == (is_out and in_id or out_id) then
-
-          if peer.id == si_target.id then
-            Log.info (si_ep, "... already linked to proper target")
-            return
-          end
-
-          -- remove old link if active, otherwise schedule rescan
-          if ((link:get_active_features() & Feature.SessionItem.ACTIVE) ~= 0) then
-            link:remove ()
-            Log.info (si_ep, "... moving to new target")
-          else
-            scheduleRescan ()
-            Log.info (si_ep, "... scheduled rescan")
-            return
-          end
-
-        end
-      end
-    end
-  end
-
-  -- create new link
-  createLink (si_ep, si_target)
-end
-
-function unhandleLinkable (si)
-  si_props = si.properties
-
-  Log.info (si, string.format("unhandling item: %s (%s)",
-      tostring(si_props["node.name"]), tostring(si_props["node.id"])))
-
-  -- remove any links associated with this item
-  for silink in links_om:iterate() do
-    local out_id = tonumber (silink.properties["out.item.id"])
-    local in_id = tonumber (silink.properties["in.item.id"])
-    if out_id == si.id or in_id == si.id then
-      silink:remove ()
-      Log.info (silink, "... link removed")
-    end
-  end
-end
-
-default_nodes = Plugin.find("default-nodes-api")
-virtuals_om = ObjectManager { Interest { type = "SiLinkable",
-  Constraint {
-    "item.factory.name", "=", "si-audio-virtual", type = "pw-global" },
-  }
-}
-linkables_om = ObjectManager {
-  Interest {
-    type = "SiLinkable",
-    -- only handle device si-audio-adapter items
-    Constraint { "item.factory.name", "=", "si-audio-adapter", type = "pw-global" },
-    Constraint { "item.node.type", "=", "device", type = "pw-global" },
-    Constraint { "active-features", "!", 0, type = "gobject" },
-  }
-}
-links_om = ObjectManager {
-  Interest {
-    type = "SiLink",
-    -- only handle links created by this policy
-    Constraint { "is.policy.virtual.device.link", "=", true, type = "pw-global" },
-  }
-}
-
--- listen for default node changes if "follow" setting is enabled
-if config.follow then
-  default_nodes:connect("changed", function (p)
-    scheduleRescan ()
-  end)
-end
-
-linkables_om:connect("objects-changed", function (om)
-  scheduleRescan ()
-end)
-
-virtuals_om:connect("object-added", function (om)
-  scheduleRescan ()
-end)
-
-linkables_om:connect("object-removed", function (om, si)
-  unhandleLinkable (si)
-end)
-
-virtuals_om:activate()
-linkables_om:activate()
-links_om:activate()

tests/modules/si-audio-virtual.c

@@ -81,9 +81,9 @@ test_si_audio_virtual_configure_activate (TestFixture * f,
     str = wp_properties_get (props, "name");
     g_assert_nonnull (str);
     g_assert_cmpstr ("virtual", ==, str);
-    str = wp_properties_get (props, "direction");
+    str = wp_properties_get (props, "item.node.direction");
     g_assert_nonnull (str);
-    g_assert_cmpstr ("1", ==, str);
+    g_assert_cmpstr ("output", ==, str);
     str = wp_properties_get (props, "item.factory.name");
     g_assert_nonnull (str);
     g_assert_cmpstr ("si-audio-virtual", ==, str);