monitor-alsa.lua

-- WirePlumber
--
-- Copyright © 2021 Collabora Ltd.
--    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
--
-- SPDX-License-Identifier: MIT

Config = {
  use_acp = true,
  use_device_reservation = true,
  enable_midi = true,
  enable_jack_client = false,
}

if Config.enable_midi then
  midi_bridge = Node("spa-node-factory", {
    ["factory.name"] = "api.alsa.seq.bridge",
    ["node.name"] = "MIDI Bridge"
  })
end

if Config.enable_jack_client then
  jack_device = Device("spa-device-factory", {
    ["factory.name"] = "api.jack.device"
  })
end

if Config.use_device_reservation then
  rd_plugin = Plugin("reserve-device")
end

function createNode(parent, id, type, factory, properties)
  local dev_props = parent.properties
  local dev = properties["api.alsa.pcm.device"] or properties["alsa.device"] or "0"
  local subdev = properties["api.alsa.pcm.subdevice"] or properties["alsa.subdevice"] or "0"
  local stream = properties["api.alsa.pcm.stream"] or "unknown"
  local profile = properties["device.profile.name"] or "unknown"
  local profile_desc = properties["device.profile.description"]

  -- ensure the node has a media class
  if not properties["media.class"] then
    if stream == "capture" then
      properties["media.class"] = "Audio/Source"
    else
      properties["media.class"] = "Audio/Sink"
    end
  end

  -- ensure the node has a name
  properties["node.nick"] = properties["node.nick"]
      or dev_props["device.nick"]
      or dev_props["api.alsa.card_name"]
      or dev_props["alsa.card_name"]

  properties["node.name"] = properties["node.name"]
      or (dev_props["device.name"] or "unknown") .. "." .. stream .. "." .. dev .. "." .. subdev

  -- ensure the node has a description
  if not properties["node.description"] then
    local desc = dev_props["device.description"] or "unknown"
    local name = properties["api.alsa.pcm.name"] or properties["api.alsa.pcm.id"] or dev

    if profile_desc then
      properties["node.description"] = desc .. " " .. profile_desc
    elseif subdev == "0" then
      properties["node.description"] = desc .. " (" .. name .. " " .. subdev .. ")"
    elseif dev == "0" then
      properties["node.description"] = desc .. " (" .. name .. ")"
    else
      properties["node.description"] = desc
    end
  end

  -- set the device id and spa factory name; REQUIRED, do not change
  properties["device.id"] = parent["bound-id"]
  properties["factory.name"] = factory

  -- create the node
  local node = Node("adapter", properties)
  node:activate(Feature.Proxy.BOUND)
  parent:store_managed_object(id, node)
end

function createDevice(parent, id, type, factory, properties)
  -- ensure the device has a name
  if not properties["device.name"] then
    local s = properties["device.bus-id"] or properties["device.bus-path"] or "unknown"
    properties["device.name"] = "alsa_card." .. s
  end

  -- ensure the device has a description
  if not properties["device.description"] then
    local d = nil
    local f = properties["device.form-factor"]
    local c = properties["device.class"]

    if f == "internal" then
      d = "Built-in Audio"
    elseif c == "modem" then
      d = "Modem"
    end

    d = d or properties["device.product.name"] or "Unknown device"
    properties["device.description"] = d
  end

  -- set the icon name
  if not properties["device.icon-name"] then
    local icon = nil
    local f = properties["device.form-factor"]
    local c = properties["device.class"]
    local b = properties["device.bus"]

    if f == "microphone" then
      icon = "audio-input-microphone"
    elseif f == "webcam" then
      icon = "camera-web"
    elseif f == "handset" then
      icon = "phone"
    elseif f == "portable" then
      icon = "multimedia-player"
    elseif f == "tv" then
      icon = "video-display"
    elseif f == "headset" then
      icon = "audio-headset"
    elseif f == "headphone" then
      icon = "audio-headphones"
    elseif f == "speaker" then
      icon = "audio-speakers"
    elseif f == "hands-free" then
      icon = "audio-handsfree"
    elseif c == "modem" then
      icon = "modem"
    end

    icon = icon or "audio-card"

    if b then b = ("-" .. b) else b = "" end
    properties["device.icon-name"] = icon .. "-analog" .. b
  end

  -- override the device factory to use ACP
  if Config.use_acp then
    factory = "api.alsa.acp.device"
  end

  -- use device reservation, if available
  if rd_plugin then
    local rd_name = "Audio" .. properties["api.alsa.card"]
    local rd = rd_plugin:call("create-reservation",
        rd_name, "WirePlumber", properties["device.name"], -20);

    properties["api.dbus.ReserveDevice1"] = rd_name

    -- unlike pipewire-media-session, this logic here keeps the device
    -- acquired at all times and destroys it if someone else acquires
    rd:connect("notify::state", function (rd, pspec)
      local state = rd["state"]

      if state == "acquired" then
        -- create the device
        local device = SpaDevice(factory, properties)
        device:connect("create-object", createNode)
        device:activate(Feature.SpaDevice.ENABLED | Feature.Proxy.BOUND)
        parent:store_managed_object(id, device)

      elseif state == "available" then
        -- attempt to acquire again
        rd:call("acquire")

      elseif state == "busy" then
        -- destroy the device
        parent:store_managed_object(id, nil)
      end
    end)

    if jack_device then
      rd:connect("notify::owner-name-changed", function (rd, pspec)
        if rd["state"] == "busy" and
           rd["owner-application-name"] == "Jack audio server" then
            -- TODO enable the jack device
        else
            -- TODO disable the jack device
        end
      end)
    end

    rd:call("acquire")
  else
    -- create the device
    local device = SpaDevice(factory, properties)
    device:connect("create-object", createNode)
    device:activate(Feature.SpaDevice.ENABLED | Feature.Proxy.BOUND)
    parent:store_managed_object(id, device)
  end
end

monitor = SpaDevice("api.alsa.enum.udev")
monitor:connect("create-object", createDevice)

function activateMonitor()
  if rd_plugin then
    monitor:connect("object-removed", function (parent, id)
      local device = parent:get_managed_object(id)
      local rd_name = device.properties["api.dbus.ReserveDevice1"]
      if rd_name then
        rd_plugin:call("destroy-reservation", rd_name)
      end
    end)
  end

  Log.info("Activating ALSA monitor")
  monitor:activate(Feature.SpaDevice.ENABLED)
end

if rd_plugin then
  -- delay activation until the d-bus connection is ready
  if rd_plugin["state"] == "connecting" then
    rd_plugin:connect("notify::state", function (rdp, pspec)
      -- "connected" -> ready
      if rd_plugin["state"] == "connected" then
        activateMonitor()

      -- "closed" -> the d-bus connection failed
      elseif rd_plugin["state"] == "closed" then
        rd_plugin = nil
        activateMonitor()
      end
      -- TODO disconnect signal handler
    end)

  -- d-bus connection has failed
  elseif rd_plugin["state"] == "closed" then
    rd_plugin = nil
    activateMonitor()

  -- d-bus connection is ready
  elseif rd_plugin["state"] == "connected" then
    activateMonitor()
  end
else
  activateMonitor()
end