From e4325bc41d5779c279f0f776ddade9974641074d Mon Sep 17 00:00:00 2001
From: Pauli Virtanen <pav@iki.fi>
Date: Sun, 27 Feb 2022 23:08:21 +0200
Subject: [PATCH] policy-node: support target.object key

Setting node target by id is not safe due to id reuse, and so
target.object which specifies the target by its object.serial was
introduced, and is used e.g. by pipewire-pulse.

Use target.object specifications in policy-node if they are present.
---
 src/scripts/create-item.lua |  2 ++
 src/scripts/policy-node.lua | 41 ++++++++++++++++++++++++++++---------
 2 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/src/scripts/create-item.lua b/src/scripts/create-item.lua
index 696ac0b9..3b2cc832 100644
--- a/src/scripts/create-item.lua
+++ b/src/scripts/create-item.lua
@@ -21,6 +21,8 @@ function configProperties(node)
     ["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"],
diff --git a/src/scripts/policy-node.lua b/src/scripts/policy-node.lua
index 1688accf..344de20e 100644
--- a/src/scripts/policy-node.lua
+++ b/src/scripts/policy-node.lua
@@ -266,32 +266,53 @@ end
 -- that is currently being handled
 function findDefinedTarget (properties)
   local metadata = config.move and metadata_om:lookup()
-  local target_id = metadata
-      and metadata:find(properties["node.id"], "target.node")
-      or properties["node.target"]
   local target_direction = getTargetDirection(properties)
+  local target_key
+  local target_value
 
-  if target_id and tonumber(target_id) then
+  if properties["target.object"] ~= nil then
+    target_value = properties["target.object"]
+    target_key = "object.serial"
+  elseif properties["node.target"] ~= nil then
+    target_value = properties["node.target"]
+    target_key = "node.id"
+  end
+
+  if metadata then
+    local id = metadata:find(properties["node.id"], "target.object")
+    if id ~= nil then
+      target_value = id
+      target_key = "object.serial"
+    else
+      id = metadata:find(properties["node.id"], "target.node")
+      if id ~= nil then
+        target_value = id
+        target_key = "node.id"
+      end
+    end
+  end
+
+  if target_value and tonumber(target_value) then
     local si_target = linkables_om:lookup {
-      Constraint { "node.id", "=", target_id },
+      Constraint { target_key, "=", target_value },
     }
     if si_target and canLink (properties, si_target) then
       return si_target, true
     end
   end
 
-  if target_id then
+  if target_value then
     for si_target in linkables_om:iterate() do
       local target_props = si_target.properties
-      if (target_props["node.name"] == target_id or
-          target_props["object.path"] == target_id) and
+      if (target_props["node.name"] == target_value or
+          target_props["object.path"] == target_value) and
           target_props["item.node.direction"] == target_direction and
           canLink (properties, si_target) then
         return si_target, true
       end
     end
   end
-  return nil, (target_id and target_id ~= "-1")
+  return nil, (target_value and target_value ~= "-1")
 end
 
 function parseParam(param, id)
@@ -815,7 +836,7 @@ end
 if config.move then
   metadata_om:connect("object-added", function (om, metadata)
     metadata:connect("changed", function (m, subject, key, t, value)
-      if key == "target.node" then
+      if key == "target.node" or key == "target.object" then
         scheduleRescan ()
       end
     end)