wireplumber/src/scripts/create-item.lua

-- WirePlumber
--
-- Copyright © 2021 Collabora Ltd.
--    @author Julian Bouzas <julian.bouzas@collabora.com>
--
-- SPDX-License-Identifier: MIT

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

items = {}

function configProperties(node)
  local np = node.properties
  local properties = {
    ["item.node"] = node,
    ["item.plugged.usec"] = GLib.get_monotonic_time(),
    ["item.features.no-dsp"] =
        Settings.get_boolean ("default-policy-audio.no-dsp"),
    ["item.features.monitor"] = true,
    ["item.features.control-port"] = false,
    ["node.id"] = node["bound-id"],
    ["client.id"] = np["client.id"],
    ["object.path"] = np["object.path"],
    ["object.serial"] = np["object.serial"],
    ["target.object"] = np["target.object"],
    ["priority.session"] = np["priority.session"],
    ["device.id"] = np["device.id"],
    ["card.profile.device"] = np["card.profile.device"],
  }

  for k, v in pairs(np) do
    if k:find("^node") or k:find("^stream") or k:find("^media") then
      properties[k] = v
    end
  end

  local media_class = properties["media.class"] or ""

  if not properties["media.type"] then
    for _, i in ipairs({ "Audio", "Video", "Midi" }) do
      if media_class:find(i) then
        properties["media.type"] = i
        break
      end
    end
  end

  properties["item.node.type"] =
      media_class:find("^Stream/") and "stream" or "device"

  if media_class:find("Sink") or
      media_class:find("Input") or
      media_class:find("Duplex") then
    properties["item.node.direction"] = "input"
  elseif media_class:find("Source") or media_class:find("Output") then
    properties["item.node.direction"] = "output"
  end
  return properties
end

AsyncEventHook {
  priority = 10,
  type = "on-event",
  name = "create-item-node-added",
  interests = {
    EventInterest {
      Constraint { "event.type", "=", "object-added" },
      Constraint { "event.subject.type", "=", "node" },
      Constraint { "media.class", "#", "Stream/*", type = "pw-global" },
    },
    EventInterest {
      Constraint { "event.type", "=", "object-added" },
      Constraint { "event.subject.type", "=", "node" },
      Constraint { "media.class", "#", "Video/*", type = "pw-global" },
    },
    EventInterest {
      Constraint { "event.type", "=", "object-added" },
      Constraint { "event.subject.type", "=", "node" },
      Constraint { "media.class", "#", "Audio/*", type = "pw-global" },
      Constraint { "wireplumber.is-endpoint", "-", type = "pw" },
    },
  },
  steps = {
    start = {
      next = "register",
      execute = function (event, transition)
        local node = event:get_subject()
        local id = node["bound-id"]
        local item
        local item_type

        local media_class = node.properties['media.class']
        if string.find (media_class, "Audio") then
          item_type = "si-audio-adapter"
        else
          item_type = "si-node"
        end

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

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

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

        Log.info(item, "activated item for node " .. tostring(id))
        item:register ()
        transition:advance()

        props = {}
        props["event.subject.type"] = "linkable"
        EventDispatcher.push_event { type = "object-added",
            priority = 50, properties = props, subject = item}
      end,
    },
  },
}:register()

SimpleEventHook {
  priority = 10,
  type = "on-event",
  name = "create-item-node-removed",
  interests = {
    EventInterest {
      Constraint { "event.type", "=", "object-removed" },
      Constraint { "event.subject.type", "=", "node" },
      Constraint { "media.class", "#", "Stream/*", type = "pw-global" },
    },
    EventInterest {
      Constraint { "event.type", "=", "object-removed" },
      Constraint { "event.subject.type", "=", "node" },
      Constraint { "media.class", "#", "Video/*", type = "pw-global" },
    },
    EventInterest {
      Constraint { "event.type", "=", "object-removed" },
      Constraint { "event.subject.type", "=", "node" },
      Constraint { "media.class", "#", "Audio/*", type = "pw-global" },
      Constraint { "wireplumber.is-endpoint", "-", type = "pw" },
    },
  },
  execute = function (_, event)
    local node = event:get_subject()
    local id = node["bound-id"]
    if items[id] then
      items[id]:remove ()
      items[id] = nil
    end

    props = {}
    props["event.subject.type"] = "linkable"
    EventDispatcher.push_event { type = "object-removed",
        priority = 50, properties = props, subject = item}
  end
}:register()