Diff

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/util/error.lua	Tue Dec 24 00:39:45 2019 +0100
@@ -0,0 +1,60 @@
+local error_mt = { __name = "error" };
+
+function error_mt:__tostring()
+	return ("error<%s:%s:%s>"):format(self.type, self.condition, self.text or "");
+end
+
+local function is_err(e)
+	return getmetatable(e) == error_mt;
+end
+
+-- Do we want any more well-known fields?
+-- Or could we just copy all fields from `e`?
+-- Sometimes you want variable details in the `text`, how to handle that?
+-- Translations?
+-- Should the `type` be restricted to the stanza error types or free-form?
+-- What to set `type` to for stream errors or SASL errors? Those don't have a 'type' attr.
+
+local function new(e, context, registry)
+	local template = (registry and registry[e]) or e or {};
+	return setmetatable({
+		type = template.type or "cancel";
+		condition = template.condition or "undefined-condition";
+		text = template.text;
+		code = template.code;
+
+		context = context or template.context or { _error_id = e };
+	}, error_mt);
+end
+
+local function coerce(ok, err, ...)
+	if ok or is_err(err) then
+		return ok, err, ...;
+	end
+
+	local new_err = setmetatable({
+		native = err;
+
+		type = "cancel";
+		condition = "undefined-condition";
+	}, error_mt);
+	return ok, new_err, ...;
+end
+
+local function from_stanza(stanza, context)
+	local error_type, condition, text = stanza:get_error();
+	return setmetatable({
+		type = error_type or "cancel";
+		condition = condition or "undefined-condition";
+		text = text;
+
+		context = context or { stanza = stanza };
+	}, error_mt);
+end
+
+return {
+	new = new;
+	coerce = coerce;
+	is_err = is_err;
+	from_stanza = from_stanza;
+}