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comparison util/events.lua @ 936:5663db788fdf

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Added: util/events.lua: An event handling library
author Waqas Hussain <waqas20@gmail.com>
date Mon, 30 Mar 2009 03:58:59 +0500
parents
children 542d49518d3a
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935:efe3eaaeff34 936:5663db788fdf
1
2 local ipairs = ipairs;
3 local pairs = pairs;
4 local t_insert = table.insert;
5 local select = select;
6
7 module "events"
8
9 function new()
10 local dispatchers = {};
11 local handlers = {};
12 local event_map = {};
13 local function _rebuild_index() -- TODO optimize index rebuilding
14 for event, _handlers in pairs(event_map) do
15 local index = handlers[event];
16 if index then
17 for i=#index,1,-1 do index[i] = nil; end
18 else index = {}; handlers[event] = index; end
19 for handler in pairs(_handlers) do
20 t_insert(index, handler);
21 end
22 end
23 end;
24 local function add_handler(event, handler)
25 local map = event_map[event];
26 if map then
27 map[handler] = true;
28 else
29 map = {[handler] = true};
30 event_map[event] = map;
31 end
32 _rebuild_index();
33 end;
34 local function remove_handler(event, handler)
35 local map = event_map[event];
36 if map then
37 map[handler] = nil;
38 _rebuild_index();
39 end
40 end;
41 local function add_plugin(plugin)
42 for event, handler in pairs(plugin) do
43 add_handler(event, handler);
44 end
45 end;
46 local function remove_plugin(plugin)
47 for event, handler in pairs(plugin) do
48 remove_handler(event, handler);
49 end
50 end;
51 local function _create_dispatcher(event) -- FIXME duplicate code in fire_event
52 local h = handlers[event];
53 if not h then h = {}; handlers[event] = h; end
54 local dispatcher = function(data)
55 for _, handler in ipairs(h) do
56 handler(data);
57 end
58 end;
59 dispatchers[event] = dispatcher;
60 return dispatcher;
61 end;
62 local function get_dispatcher(event)
63 return dispatchers[event] or _create_dispatcher(event);
64 end;
65 local function fire_event(event, data) -- FIXME duplicates dispatcher code
66 local h = handlers[event];
67 if h then
68 for _, handler in ipairs(h) do
69 handler(data);
70 end
71 end
72 end;
73 local function get_named_arg_dispatcher(event, ...)
74 local dispatcher = get_dispatcher(event);
75 local keys = {...};
76 local data = {};
77 return function(...)
78 for i, key in ipairs(keys) do data[key] = select(i, ...); end
79 dispatcher(data);
80 end;
81 end;
82 return {
83 add_handler = add_handler;
84 remove_handler = remove_handler;
85 add_plugin = add_plugin;
86 remove_plugin = remove_plugin;
87 get_dispatcher = get_dispatcher;
88 fire_event = fire_event;
89 get_named_arg_dispatcher = get_named_arg_dispatcher;
90 _dispatchers = dispatchers;
91 _handlers = handlers;
92 _event_map = event_map;
93 };
94 end
95
96 return _M;