The patch is mainly to export client_array_t object to Lua,
but can be used to export any ..._array_t object.
The idea: export to Lua not a table, but userdata with
metamethods to get/set/define length of ..._array_t object
directly.
Now when I get clients field from tag object C code
creates full copy of client_array_t structure into Lua table.
It takes traversing a whole array of data.
I did it in other way: userdata is exported, with __index,
__newindex, and __len meta-methods defined, and Lua
script gains direct access to client_array_t C-array:
it can get client object, get length of array and assign
client objects to some index in C-array.
Pros:
No overhead of creation a copy of C-structure into Lua-table:
if I want just to test a number of clients for a tag, I don't need
a whole loop to build table, I just want to read clients->len field,
and I do so via __len meta-method.
Also if I want to get some client from tags.clients, I don't need
to create ALL clients Lua-objects, I just get client_t C-struct
and create Lua-object from it. Just in place.
So Lua-loop enuming all tag.clients is not 2 loops internally
(first create copy of tag.clients into Lua-table, then enum this table),
but only one, and if I break out of loop in the middle, I create
only some client Lua-objects, not all of them from tag.clients.
Contras:
As far as clients field is not a table, I cant use pairs/ipairs
and other table functions for it.
But it can be implemented in other way:
for k,c pairs(tag.clients) => for k = 1, #tag.clients,
table.insert(tag.clients, client) => tag.clients[#tag.clients+1] = client
etc.
One more Pro now:
As far as tag.clients in current implementation returns copy of data
table.insert doesn't do what's expected: it doesn't really add client
into tag.clients "array".
With my implementation client is added as expected, as we work with
client_array_t structure directly.
Signed-off-by: Julien Danjou <julien@danjou.info>
Julien Danjou
Konstantin
Pierre Habouzit
Michael Gehring