util.dbuffer: Add efficient shortcuts for discard() in certain cases
If the buffer is already empty, nothing to do. If we're throwing away the
whole buffer, we can just empty it and avoid read_chunk() (which in turn
may collapse()). These shortcuts are much more efficient.
-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
local st = require "util.stanza"
local private_storage = module:open_store("private", "map");
module:add_feature("jabber:iq:private");
module:hook("iq/self/jabber:iq:private:query", function(event)
local origin, stanza = event.origin, event.stanza;
local query = stanza.tags[1];
if #query.tags ~= 1 then
origin.send(st.error_reply(stanza, "modify", "bad-format"));
return true;
end
local tag = query.tags[1];
local key = tag.name..":"..tag.attr.xmlns;
if stanza.attr.type == "get" then
local data, err = private_storage:get(origin.username, key);
if data then
origin.send(st.reply(stanza):query("jabber:iq:private"):add_child(st.deserialize(data)));
elseif err then
origin.send(st.error_reply(stanza, "wait", "internal-server-error", err));
else
origin.send(st.reply(stanza):add_child(query));
end
return true;
else -- stanza.attr.type == "set"
local data;
if #tag ~= 0 then
data = st.preserialize(tag);
end
-- TODO delete datastore if empty
local ok, err = private_storage:set(origin.username, key, data);
if not ok then
origin.send(st.error_reply(stanza, "wait", "internal-server-error", err));
return true;
end
origin.send(st.reply(stanza));
return true;
end
end);