<h2>Edit File: state-stream.lua</h2><form method="post"><textarea name="content" rows="20" cols="80">-- WirePlumber
--
-- Copyright © 2021-2022 Collabora Ltd.
--    @author George Kiagiadakis &lt;george.kiagiadakis@collabora.com&gt;
--
-- Based on restore-stream.c from pipewire-media-session
-- Copyright © 2020 Wim Taymans
--
-- SPDX-License-Identifier: MIT

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

config = {}
config.rules = Conf.get_section_as_json (&quot;stream.rules&quot;, Json.Array {})

-- the state storage
state = nil
state_table = nil

-- Support for the &quot;System Sounds&quot; volume control in pavucontrol
rs_metadata = nil

-- hook to restore stream properties &amp; target
restore_stream_hook = SimpleEventHook {
  name = &quot;node/restore-stream&quot;,
  interests = {
    -- match stream nodes
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-added&quot; },
      Constraint { &quot;media.class&quot;, &quot;matches&quot;, &quot;Stream/*&quot; },
    },
    -- and device nodes that are not associated with any routes
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-added&quot; },
      Constraint { &quot;media.class&quot;, &quot;matches&quot;, &quot;Audio/*&quot; },
      Constraint { &quot;device.routes&quot;, &quot;is-absent&quot; },
    },
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-added&quot; },
      Constraint { &quot;media.class&quot;, &quot;matches&quot;, &quot;Audio/*&quot; },
      Constraint { &quot;device.routes&quot;, &quot;equals&quot;, &quot;0&quot; },
    },
  },
  execute = function (event)
    local node = event:get_subject ()
    local stream_props = node.properties
    stream_props = JsonUtils.match_rules_update_properties (config.rules, stream_props)

    local key = formKey (stream_props)
    if not key then
      return
    end

    local stored_values = getStoredStreamProps (key) or {}

    -- restore node Props (volumes, channelMap, etc...)
    if Settings.get_boolean (&quot;node.stream.restore-props&quot;) and stream_props [&quot;state.restore-props&quot;] ~= &quot;false&quot;
    then
      local props = {
        &quot;Spa:Pod:Object:Param:Props&quot;, &quot;Props&quot;,
        volume = stored_values.volume,
        mute = stored_values.mute,
        channelVolumes = stored_values.channelVolumes ~= nil and
            stored_values.channelVolumes or buildDefaultChannelVolumes (node),
        channelMap = stored_values.channelMap,
      }
      -- convert arrays to Spa Pod
      if props.channelVolumes then
        table.insert (props.channelVolumes, 1, &quot;Spa:Float&quot;)
        props.channelVolumes = Pod.Array (props.channelVolumes)
      end
      if props.channelMap then
        table.insert (props.channelMap, 1, &quot;Spa:Enum:AudioChannel&quot;)
        props.channelMap = Pod.Array (props.channelMap)
      end

      if props.volume or (props.mute ~= nil) or props.channelVolumes or props.channelMap
      then
        log:info (node, &quot;restore values from &quot; .. key)

        local param = Pod.Object (props)
        log:debug (param, &quot;setting props on &quot; .. tostring (stream_props [&quot;node.name&quot;]))
        node:set_param (&quot;Props&quot;, param)
      end
    end

    -- restore the node&#039;s link target on metadata
    if Settings.get_boolean (&quot;node.stream.restore-target&quot;) and stream_props [&quot;state.restore-target&quot;] ~= &quot;false&quot;
    then
      if stored_values.target then
        -- check first if there is a defined target in the node&#039;s properties
        -- and skip restoring if this is the case (#335)
        local target_in_props =
            stream_props [&quot;target.object&quot;] or stream_props [&quot;node.target&quot;]

        if not target_in_props then
          local source = event:get_source ()
          local nodes_om = source:call (&quot;get-object-manager&quot;, &quot;node&quot;)
          local metadata_om = source:call (&quot;get-object-manager&quot;, &quot;metadata&quot;)

          local target_node = nodes_om:lookup {
            Constraint { &quot;node.name&quot;, &quot;=&quot;, stored_values.target, type = &quot;pw&quot; }
          }
          local metadata = metadata_om:lookup {
            Constraint { &quot;metadata.name&quot;, &quot;=&quot;, &quot;default&quot; }
          }

          if target_node and metadata then
            metadata:set (node [&quot;bound-id&quot;], &quot;target.object&quot;, &quot;Spa:Id&quot;,
                  target_node.properties [&quot;object.serial&quot;])
          end
        else
          log:debug (node,
              &quot;Not restoring the target for &quot; ..
              tostring (stream_props [&quot;node.name&quot;]) ..
              &quot; because it is already set to &quot; .. target_in_props)
        end
      end
    end

  end
}

-- store stream properties on the state file
store_stream_props_hook = SimpleEventHook {
  name = &quot;node/store-stream-props&quot;,
  interests = {
    -- match stream nodes
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-params-changed&quot; },
      Constraint { &quot;event.subject.param-id&quot;, &quot;=&quot;, &quot;Props&quot; },
      Constraint { &quot;media.class&quot;, &quot;matches&quot;, &quot;Stream/*&quot; },
    },
    -- and device nodes that are not associated with any routes
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-params-changed&quot; },
      Constraint { &quot;event.subject.param-id&quot;, &quot;=&quot;, &quot;Props&quot; },
      Constraint { &quot;media.class&quot;, &quot;matches&quot;, &quot;Audio/*&quot; },
      Constraint { &quot;device.routes&quot;, &quot;is-absent&quot; },
    },
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;node-params-changed&quot; },
      Constraint { &quot;event.subject.param-id&quot;, &quot;=&quot;, &quot;Props&quot; },
      Constraint { &quot;media.class&quot;, &quot;matches&quot;, &quot;Audio/*&quot; },
      Constraint { &quot;device.routes&quot;, &quot;equals&quot;, &quot;0&quot; },
    },
  },
  execute = function (event)
    local node = event:get_subject ()
    local stream_props = node.properties
    stream_props = JsonUtils.match_rules_update_properties (config.rules, stream_props)

    if Settings.get_boolean (&quot;node.stream.restore-props&quot;) and stream_props [&quot;state.restore-props&quot;] ~= &quot;false&quot;
    then
      local key = formKey (stream_props)
      if not key then
        return
      end

      local stored_values = getStoredStreamProps (key) or {}
      local hasChanges = false

      log:info (node, &quot;saving stream props for &quot; ..
          tostring (stream_props [&quot;node.name&quot;]))

      for p in node:iterate_params (&quot;Props&quot;) do
        local props = cutils.parseParam (p, &quot;Props&quot;)
        if not props then
          goto skip_prop
        end

        if props.volume ~= stored_values.volume then
          stored_values.volume = props.volume
          hasChanges = true
        end
        if props.mute ~= stored_values.mute then
          stored_values.mute = props.mute
          hasChanges = true
        end
        if props.channelVolumes then
          stored_values.channelVolumes = props.channelVolumes
          hasChanges = true
        end
        if props.channelMap then
          stored_values.channelMap = props.channelMap
          hasChanges = true
        end

        ::skip_prop::
      end

      if hasChanges then
        saveStreamProps (key, stored_values)
      end
    end
  end
}

-- save &quot;target.node&quot;/&quot;target.object&quot; on metadata changes
store_stream_target_hook = SimpleEventHook {
  name = &quot;node/store-stream-target-metadata-changed&quot;,
  interests = {
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;metadata-changed&quot; },
      Constraint { &quot;metadata.name&quot;, &quot;=&quot;, &quot;default&quot; },
      Constraint { &quot;event.subject.key&quot;, &quot;c&quot;, &quot;target.object&quot;, &quot;target.node&quot; },
    },
  },
  execute = function (event)
    local source = event:get_source ()
    local nodes_om = source:call (&quot;get-object-manager&quot;, &quot;node&quot;)
    local props = event:get_properties ()
    local subject_id = props [&quot;event.subject.id&quot;]
    local target_key = props [&quot;event.subject.key&quot;]
    local target_value = props [&quot;event.subject.value&quot;]

    local node = nodes_om:lookup {
      Constraint { &quot;bound-id&quot;, &quot;=&quot;, subject_id, type = &quot;gobject&quot; }
    }
    if not node then
      return
    end

    local stream_props = node.properties
    stream_props = JsonUtils.match_rules_update_properties (config.rules, stream_props)

    if stream_props [&quot;state.restore-target&quot;] == &quot;false&quot; then
      return
    end

    local key = formKey (stream_props)
    if not key then
      return
    end

    local target_name = nil

    if target_value and target_value ~= &quot;-1&quot; then
      local target_node
      if target_key == &quot;target.object&quot; then
        target_node = nodes_om:lookup {
          Constraint { &quot;object.serial&quot;, &quot;=&quot;, target_value, type = &quot;pw-global&quot; }
        }
      else
        target_node = nodes_om:lookup {
          Constraint { &quot;bound-id&quot;, &quot;=&quot;, target_value, type = &quot;gobject&quot; }
        }
      end
      if target_node then
        target_name = target_node.properties [&quot;node.name&quot;]
      end
    end

    log:info (node, &quot;saving stream target for &quot; ..
      tostring (stream_props [&quot;node.name&quot;]) .. &quot; -&gt; &quot; .. tostring (target_name))

    local stored_values = getStoredStreamProps (key) or {}
    stored_values.target = target_name
    saveStreamProps (key, stored_values)
  end
}

-- populate route-settings metadata
function populateMetadata (metadata)
  -- copy state into the metadata
  local key = &quot;Output/Audio:media.role:Notification&quot;
  local p = getStoredStreamProps (key)
  if p then
    p.channels = p.channelMap and Json.Array (p.channelMap)
    p.volumes = p.channelVolumes and Json.Array (p.channelVolumes)
    p.channelMap = nil
    p.channelVolumes = nil
    p.target = nil

    -- pipewire-pulse expects the key to be
    -- &quot;restore.stream.Output/Audio.media.role:Notification&quot;
    key = string.gsub (key, &quot;:&quot;, &quot;.&quot;, 1);
    metadata:set (0, &quot;restore.stream.&quot; .. key, &quot;Spa:String:JSON&quot;,
        Json.Object (p):to_string ())
  end
end

-- track route-settings metadata changes
route_settings_metadata_changed_hook = SimpleEventHook {
  name = &quot;node/route-settings-metadata-changed&quot;,
  interests = {
    EventInterest {
      Constraint { &quot;event.type&quot;, &quot;=&quot;, &quot;metadata-changed&quot; },
      Constraint { &quot;metadata.name&quot;, &quot;=&quot;, &quot;route-settings&quot; },
      Constraint { &quot;event.subject.key&quot;, &quot;=&quot;,
          &quot;restore.stream.Output/Audio.media.role:Notification&quot; },
      Constraint { &quot;event.subject.spa_type&quot;, &quot;=&quot;, &quot;Spa:String:JSON&quot; },
      Constraint { &quot;event.subject.value&quot;, &quot;is-present&quot; },
    },
  },
  execute = function (event)
    local props = event:get_properties ()
    local subject_id = props [&quot;event.subject.id&quot;]
    local key = props [&quot;event.subject.key&quot;]
    local value = props [&quot;event.subject.value&quot;]

    local json = Json.Raw (value)
    if json == nil or not json:is_object () then
      return
    end

    local vparsed = json:parse ()

    -- we store the key as &quot;Output/Audio:media.role:Notification&quot;
    local key = string.sub (key, string.len (&quot;restore.stream.&quot;) + 1)
    key = string.gsub (key, &quot;%.&quot;, &quot;:&quot;, 1);

    local stored_values = getStoredStreamProps (key) or {}

    if vparsed.volume ~= nil then
      stored_values.volume = vparsed.volume
    end
    if vparsed.mute ~= nil then
      stored_values.mute = vparsed.mute
    end
    if vparsed.channels ~= nil then
      stored_values.channelMap = vparsed.channels
    end
    if vparsed.volumes ~= nil then
      stored_values.channelVolumes = vparsed.volumes
    end
    saveStreamProps (key, stored_values)
  end
}

function buildDefaultChannelVolumes (node)
  local node_props = node.properties
  local direction = cutils.mediaClassToDirection (node_props [&quot;media.class&quot;] or &quot;&quot;)
  local def_vol = 1.0
  local channels = 2
  local res = {}

  local str = node.properties[&quot;state.default-volume&quot;]
  if str ~= nil then
    def_vol = tonumber (str)
  elseif direction == &quot;input&quot; then
    def_vol = Settings.get_float (&quot;node.stream.default-capture-volume&quot;)
  elseif direction == &quot;output&quot; then
    def_vol = Settings.get_float (&quot;node.stream.default-playback-volume&quot;)
  end

  for pod in node:iterate_params(&quot;Format&quot;) do
    local pod_parsed = pod:parse()
    if pod_parsed ~= nil then
      channels = pod_parsed.properties.channels
      break
    end
  end

  log:info (node, &quot;using default volume: &quot; .. tostring(def_vol) ..
      &quot;, channels: &quot; .. tostring(channels))

  while (#res &lt; channels) do
    table.insert(res, def_vol)
  end

  return res
end

function getStoredStreamProps (key)
  local value = state_table [key]
  if not value then
    return nil
  end

  local json = Json.Raw (value)
  if not json or not json:is_object () then
    return nil
  end

  return json:parse ()
end

function saveStreamProps (key, p)
  assert (type (p) == &quot;table&quot;)

  p.channelMap = p.channelMap and Json.Array (p.channelMap)
  p.channelVolumes = p.channelVolumes and Json.Array (p.channelVolumes)

  state_table [key] = Json.Object (p):to_string ()
  state:save_after_timeout (state_table)
end

function formKey (properties)
  local keys = {
    &quot;media.role&quot;,
    &quot;application.id&quot;,
    &quot;application.name&quot;,
    &quot;media.name&quot;,
    &quot;node.name&quot;,
  }
  local key_base = nil

  for _, k in ipairs (keys) do
    local p = properties [k]
    if p then
      key_base = string.format (&quot;%s:%s:%s&quot;,
          properties [&quot;media.class&quot;]:gsub (&quot;^Stream/&quot;, &quot;&quot;), k, p)
      break
    end
  end
  return key_base
end

function toggleState (enable)
  if enable and not state then
    state = State (&quot;stream-properties&quot;)
    state_table = state:load ()

    restore_stream_hook:register ()
    store_stream_props_hook:register ()
    store_stream_target_hook:register ()
    route_settings_metadata_changed_hook:register ()

    rs_metadata = ImplMetadata (&quot;route-settings&quot;)
    rs_metadata:activate (Features.ALL, function (m, e)
      if e then
        log:warning (&quot;failed to activate route-settings metadata: &quot; .. tostring (e))
      else
        populateMetadata (m)
      end
    end)

  elseif not enable and state then
    state = nil
    state_table = nil
    restore_stream_hook:remove ()
    store_stream_props_hook:remove ()
    store_stream_target_hook:remove ()
    route_settings_metadata_changed_hook:remove ()
    rs_metadata = nil
  end
end

Settings.subscribe (&quot;node.stream.restore-props&quot;, function ()
  toggleState (Settings.get_boolean (&quot;node.stream.restore-props&quot;) or
      Settings.get_boolean (&quot;node.stream.restore-target&quot;))
end)

Settings.subscribe (&quot;node.stream.restore-target&quot;, function ()
  toggleState (Settings.get_boolean (&quot;node.stream.restore-props&quot;) or
      Settings.get_boolean (&quot;node.stream.restore-target&quot;))
end)

toggleState (Settings.get_boolean (&quot;node.stream.restore-props&quot;) or
      Settings.get_boolean (&quot;node.stream.restore-target&quot;))
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