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local id = require "util.id";
-- Library configuration (see configure())
local auto_inject_traceback = false;
local display_tracebacks = false;
local error_mt = { __name = "error" };
function error_mt:__tostring()
if display_tracebacks and self.context.traceback then
return ("error<%s:%s:%s:%s>"):format(self.type, self.condition, self.text or "", self.context.traceback);
end
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
local function configure(opt)
if opt.display_tracebacks ~= nil then
display_tracebacks = opt.display_tracebacks;
end
if opt.auto_inject_traceback ~= nil then
auto_inject_traceback = opt.auto_inject_traceback;
end
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, source)
local template = registry and registry[e];
if not template then
if type(e) == "table" then
template = {
code = e.code;
type = e.type;
condition = e.condition;
text = e.text;
extra = e.extra;
};
else
template = {};
end
end
context = context or {};
if auto_inject_traceback then
context.traceback = debug.traceback("error stack", 2);
end
local error_instance = setmetatable({
instance_id = id.short();
type = template.type or "cancel";
condition = template.condition or "undefined-condition";
text = template.text;
code = template.code;
extra = template.extra;
context = context;
source = source;
}, error_mt);
return error_instance;
end
-- compact --> normal form
local function expand_registry(namespace, registry)
local mapped = {}
for err,template in pairs(registry) do
local e = {
type = template[1];
condition = template[2];
text = template[3];
};
if namespace and template[4] then
e.extra = { namespace = namespace, condition = template[4] };
end
mapped[err] = e;
end
return mapped;
end
local function init(source, namespace, registry)
if type(namespace) == "table" then
-- registry can be given as second argument if namespace is either not used
registry, namespace = namespace, nil;
end
local _, protoerr = next(registry, nil);
if protoerr and type(next(protoerr)) == "number" then
registry = expand_registry(namespace, registry);
end
return {
source = source;
registry = registry;
new = function (e, context)
return new(e, context, registry, source);
end;
};
end
local function coerce(ok, err, ...)
if ok or is_err(err) then
return ok, err, ...;
end
local new_err = new({
type = "cancel", condition = "undefined-condition"
}, { wrapped_error = err });
return ok, new_err, ...;
end
local function from_stanza(stanza, context, source)
local error_type, condition, text, extra_tag = stanza:get_error();
local error_tag = stanza:get_child("error");
context = context or {};
context.stanza = stanza;
context.by = error_tag.attr.by or stanza.attr.from;
local uri;
if condition == "gone" or condition == "redirect" then
uri = error_tag:get_child_text(condition, "urn:ietf:params:xml:ns:xmpp-stanzas");
end
return new({
type = error_type or "cancel";
condition = condition or "undefined-condition";
text = text;
extra = (extra_tag or uri) and {
uri = uri;
tag = extra_tag;
} or nil;
}, context, nil, source);
end
return {
new = new;
init = init;
coerce = coerce;
is_err = is_err;
from_stanza = from_stanza;
configure = configure;
}
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