<h2>Edit File: create-item.lua</h2><form method="post"><textarea name="content" rows="20" cols="80">-- WirePlumber
--
-- Copyright © 2021 Collabora Ltd.
--    @author Julian Bouzas &lt;julian.bouzas@collabora.com&gt;
--
-- SPDX-License-Identifier: MIT

-- create-item.lua script takes pipewire nodes and creates session items (a.k.a
-- linkable) objects out of them.

cutils = require (&quot;common-utils&quot;)
log = Log.open_topic (&quot;s-node&quot;)

items = {}

function configProperties (node)
  local properties = node.properties
  local media_class = properties [&quot;media.class&quot;] or &quot;&quot;

  -- ensure a media.type is set
  if not properties [&quot;media.type&quot;] then
    for _, i in ipairs ({ &quot;Audio&quot;, &quot;Video&quot;, &quot;Midi&quot; }) do
      if media_class:find (i) then
        properties [&quot;media.type&quot;] = i
        break
      end
    end
  end

  properties [&quot;item.node&quot;] = node
  properties [&quot;item.node.direction&quot;] =
      cutils.mediaClassToDirection (media_class)
  properties [&quot;item.node.type&quot;] =
      media_class:find (&quot;^Stream/&quot;) and &quot;stream&quot; or &quot;device&quot;
  properties [&quot;item.plugged.usec&quot;] = GLib.get_monotonic_time ()
  properties [&quot;item.features.no-dsp&quot;] =
      Settings.get_boolean (&quot;node.features.audio.no-dsp&quot;)
  properties [&quot;item.features.monitor&quot;] =
      Settings.get_boolean (&quot;node.features.audio.monitor-ports&quot;)
  properties [&quot;item.features.control-port&quot;] =
      Settings.get_boolean (&quot;node.features.audio.control-port&quot;)
  properties [&quot;item.features.mono&quot;] =
      Settings.get_boolean (&quot;node.features.audio.mono&quot;)
  properties [&quot;node.id&quot;] = node [&quot;bound-id&quot;]

  -- set the default media.role, if configured
  -- avoid Settings.get_string(), as it will parse the default &quot;null&quot; value
  -- as a string instead of returning nil
  local default_role = Settings.get (&quot;node.stream.default-media-role&quot;)
  if default_role then
    default_role = default_role:parse()
    properties [&quot;media.role&quot;] = properties [&quot;media.role&quot;] or default_role
  end

  return properties
end

AsyncEventHook {
  name = &quot;node/create-item&quot;,
  interests = {
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-added&quot; },
      Constraint { &quot;media.class&quot;, &quot;#&quot;, &quot;Stream/*&quot;, type = &quot;pw-global&quot; },
    },
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-added&quot; },
      Constraint { &quot;media.class&quot;, &quot;#&quot;, &quot;Video/*&quot;, type = &quot;pw-global&quot; },
    },
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-added&quot; },
      Constraint { &quot;media.class&quot;, &quot;#&quot;, &quot;Audio/*&quot;, type = &quot;pw-global&quot; },
      Constraint { &quot;wireplumber.is-virtual&quot;, &quot;-&quot;, type = &quot;pw&quot; },
    },
  },
  steps = {
    start = {
      next = &quot;register&quot;,
      execute = function (event, transition)
        local node = event:get_subject ()
        local id = node.id
        local item
        local item_type

        local media_class = node.properties [&#039;media.class&#039;]
        if string.find (media_class, &quot;Audio&quot;) then
          item_type = &quot;si-audio-adapter&quot;
        else
          item_type = &quot;si-node&quot;
        end

        log:info (node, &quot;creating item for node -&gt; &quot; .. item_type)

        -- create item
        item = SessionItem (item_type)
        items [id] = item

        -- configure item
        if not item:configure (configProperties (node)) then
          transition:return_error (&quot;failed to configure item for node &quot;
              .. tostring (id))
          return
        end

        -- activate item
        item:activate (Features.ALL, function (_, e)
          if e then
            transition:return_error (&quot;failed to activate item: &quot;
                .. tostring (e));
          else
            transition:advance ()
          end
        end)
      end,
    },
    register = {
      next = &quot;none&quot;,
      execute = function (event, transition)
        local node = event:get_subject ()
        local bound_id = node [&quot;bound-id&quot;]
        local item = items [node.id]

        log:info (item, &quot;activated item for node &quot; .. tostring (bound_id))
        item:register ()
        transition:advance ()
      end,
    },
  },
}:register ()

SimpleEventHook {
  name = &quot;node/destroy-item&quot;,
  interests = {
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-removed&quot; },
      Constraint { &quot;media.class&quot;, &quot;#&quot;, &quot;Stream/*&quot;, type = &quot;pw-global&quot; },
    },
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-removed&quot; },
      Constraint { &quot;media.class&quot;, &quot;#&quot;, &quot;Video/*&quot;, type = &quot;pw-global&quot; },
    },
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-removed&quot; },
      Constraint { &quot;media.class&quot;, &quot;#&quot;, &quot;Audio/*&quot;, type = &quot;pw-global&quot; },
      Constraint { &quot;wireplumber.is-virtual&quot;, &quot;-&quot;, type = &quot;pw&quot; },
    },
  },
  execute = function (event)
    local node = event:get_subject ()
    local id = node.id
    if items [id] then
      items [id]:remove ()
      items [id] = nil
    end

  end
}:register ()

function reconfigureAudioAdapters ()
  local ids = {}

  -- Get the Id of all session items that are audio adapters
  for id, item in pairs(items) do
    local si_props = item.properties
    if si_props [&quot;item.factory.name&quot;] == &quot;si-audio-adapter&quot; then
      table.insert (ids, id)
    end
  end

  -- Re-configure all audio adapters
  for _, id in pairs (ids) do
    local item = items[id]
    local node = item:get_associated_proxy (&quot;node&quot;)

    log:info (item, &quot;Started re-configuring audio adapter&quot;)

    -- Remove the session item so that it is unlinked
    items[id] = nil
    item:remove()

    -- Configure the session item
    if not item:configure (configProperties (node)) then
      log:warning (item, &quot;Could not re-configure audio adapter&quot;)
      goto skip_item
    end

    -- Activate the session item so that it is linked again
    items[id] = item
    item:activate (Features.ALL, function (si, e)
      if e then
        log:warning (si, &quot;Could not re-activate audio adapter&quot;)
      else
        log:info (si, &quot;Successfully re-activated audio adapter&quot;)
        si:register ()
      end
    end)

    ::skip_item::
  end
end

Settings.subscribe (&quot;node.features.audio.*&quot;, function ()
  reconfigureAudioAdapters ()
end)
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