From 8ac96f4a377831614fc252a60ca46709d99c5c50 Mon Sep 17 00:00:00 2001
From: Julian Bouzas <julian.bouzas@collabora.com>
Date: Tue, 31 Oct 2023 12:28:18 -0400
Subject: [PATCH] linking: handle 'target.linger' property

When set to 'true', the node will remain alive without any error produced if
it cannot be linked to its specified target; in all other cases, an error will
be produced and the node will be destroyed.
---
 src/scripts/lib/linking-utils.lua           | 14 ++++++++++++++
 src/scripts/linking/find-defined-target.lua | 10 +++++++++-
 src/scripts/linking/find-filter-target.lua  | 12 ++++++++++--
 src/scripts/linking/prepare-link.lua        | 18 ++----------------
 4 files changed, 35 insertions(+), 19 deletions(-)

diff --git a/src/scripts/lib/linking-utils.lua b/src/scripts/lib/linking-utils.lua
index 0a422f4b..15f2433c 100644
--- a/src/scripts/lib/linking-utils.lua
+++ b/src/scripts/lib/linking-utils.lua
@@ -303,4 +303,18 @@ function putils.haveAvailableRoutes (si_props)
   return false
 end
 
+function putils.sendClientError (event, node, message)
+  local source = event:get_source ()
+  local client_id = node.properties ["client.id"]
+  if client_id then
+    local clients_om = source:call ("get-object-manager", "client")
+    local client = clients_om:lookup {
+        Constraint { "bound-id", "=", client_id, type = "gobject" }
+    }
+    if client then
+      client:send_error (node ["bound-id"], -2, message)
+    end
+  end
+end
+
 return putils
diff --git a/src/scripts/linking/find-defined-target.lua b/src/scripts/linking/find-defined-target.lua
index 8e687fce..62b316e5 100644
--- a/src/scripts/linking/find-defined-target.lua
+++ b/src/scripts/linking/find-defined-target.lua
@@ -38,6 +38,7 @@ SimpleEventHook {
     local node = si:get_associated_proxy ("node")
     local dont_fallback = cutils.parseBool (node.properties ["target.dont-fallback"])
     local dont_move = cutils.parseBool (node.properties ["target.dont-move"])
+    local linger = cutils.parseBool (node.properties ["target.linger"])
     local target_key
     local target_value = nil
     local node_defined = false
@@ -113,7 +114,14 @@ SimpleEventHook {
       si_flags.can_passthrough = can_passthrough
       event:set_data ("target", target)
     elseif target_value and dont_fallback then
-      log:info(si, "... waiting for defined target as dont-fallback is set")
+      -- send error to client and destroy node if linger is not set
+      if not linger then
+        putils.sendClientError (event, node, "defined target not found")
+        node:request_destroy ()
+        log:info(si, "... destroyed node as defined target was not found")
+      else
+        log:info(si, "... waiting for defined target as dont-fallback is set")
+      end
       event:stop_processing ()
     end
 
diff --git a/src/scripts/linking/find-filter-target.lua b/src/scripts/linking/find-filter-target.lua
index 97904035..1f6a0f4d 100644
--- a/src/scripts/linking/find-filter-target.lua
+++ b/src/scripts/linking/find-filter-target.lua
@@ -51,6 +51,7 @@ SimpleEventHook {
 
     local node = si:get_associated_proxy ("node")
     local dont_fallback = cutils.parseBool (node.properties ["target.dont-fallback"])
+    local linger = cutils.parseBool (node.properties ["target.linger"])
     local target_picked = false
     local allow_fallback
 
@@ -64,7 +65,7 @@ SimpleEventHook {
       passthrough_compatible, can_passthrough =
           putils.checkPassthroughCompatibility (si, target)
       if putils.canLink (si_props, target) and passthrough_compatible then
-        target_picked = true;
+        target_picked = true
       end
     end
 
@@ -77,7 +78,14 @@ SimpleEventHook {
       si_flags.can_passthrough = can_passthrough
       event:set_data ("target", target)
     elseif is_smart_filter and dont_fallback then
-      log:info(si, "... waiting for smart filter defined target as dont-fallback is set")
+      -- send error to client and destroy node if linger is not set
+      if not linger then
+        putils.sendClientError (event, node, "smart filter defined target not found")
+        node:request_destroy ()
+        log:info(si, "... destroyed node as smart filter defined target was not found")
+      else
+        log:info(si, "... waiting for smart filter defined target as dont-fallback is set")
+      end
       event:stop_processing ()
     end
   end
diff --git a/src/scripts/linking/prepare-link.lua b/src/scripts/linking/prepare-link.lua
index 2e4fb85f..def59960 100644
--- a/src/scripts/linking/prepare-link.lua
+++ b/src/scripts/linking/prepare-link.lua
@@ -100,22 +100,8 @@ SimpleEventHook {
         return
       end
 
-      local client_id = node.properties ["client.id"]
-      if client_id then
-        local clients_om = source:call ("get-object-manager", "client")
-        local client = clients_om:lookup {
-          Constraint { "bound-id", "=", client_id, type = "gobject" }
-        }
-        local message
-        if reconnect then
-          message = "no target node available"
-        else
-          message = "target not found"
-        end
-        if client then
-          client:send_error (node ["bound-id"], -2, message)
-        end
-      end
+      putils.sendClientError (event, node,
+          reconnect and "no target node available" or "target not found")
 
       if not reconnect then
         log:info (si, "... destroy node")