Instance: add method FindOutput()

Move code from handle_moveoutput().

src/Instance.cxx

@@ -90,6 +90,22 @@ Instance::DeletePartition(Partition &partition) noexcept
 	}
 }
 
+AudioOutputControl *
+Instance::FindOutput(std::string_view name,
+		     Partition &excluding_partition) noexcept
+{
+	for (auto &partition : partitions) {
+		if (&partition == &excluding_partition)
+			continue;
+
+		auto *output = partition.outputs.FindByName(name);
+		if (output != nullptr && !output->IsDummy())
+			return output;
+	}
+
+	return nullptr;
+}
+
 #ifdef ENABLE_DATABASE
 
 const Database &

src/Instance.hxx

@@ -38,6 +38,7 @@ class InotifyUpdate;
 
 class ClientList;
 struct Partition;
+class AudioOutputControl;
 class StateFile;
 class RemoteTagCache;
 class StickerDatabase;
@@ -171,6 +172,17 @@ struct Instance final
 
 	void BeginShutdownPartitions() noexcept;
 
+	/**
+	 * Returns the (non-dummy) audio output device with the
+	 * specified name.  Returns nullptr if the name does not
+	 * exist.
+	 *
+	 * @param excluding_partition ignore this partition
+	 */
+	[[gnu::pure]]
+	AudioOutputControl *FindOutput(std::string_view name,
+				       Partition &excluding_partition) noexcept;
+
 #ifdef ENABLE_DATABASE
 	/**
 	 * Returns the global #Database instance.  May return nullptr

src/command/PartitionCommands.cxx

@@ -145,13 +145,12 @@ handle_moveoutput(Client &client, Request request, Response &response)
 
 	/* find the partition which owns this output currently */
 	auto &instance = client.GetInstance();
-	for (auto &partition : instance.partitions) {
-		if (&partition == &dest_partition)
-			continue;
 
-		auto *output = partition.outputs.FindByName(output_name);
+	auto *output = instance.FindOutput(output_name, dest_partition);
-		if (output == nullptr || output->IsDummy())
+	if (output == nullptr) {
-			continue;
+		response.Error(ACK_ERROR_NO_EXIST, "No such output");
+		return CommandResult::ERROR;
+	}
 
 	const bool was_enabled = output->IsEnabled();
 
@@ -166,8 +165,4 @@ handle_moveoutput(Client &client, Request request, Response &response)
 
 	instance.EmitIdle(IDLE_OUTPUT);
 	return CommandResult::OK;
-	}
-
-	response.Error(ACK_ERROR_NO_EXIST, "No such output");
-	return CommandResult::ERROR;
 }