1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
/*
* This file is part of libdom.
* Licensed under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
* Copyright 2009 Bo Yang <struggleyb.nku@gmail.com>
*/
#ifndef dom_events_document_event_h_
#define dom_events_document_event_h_
#include <stdbool.h>
#include <dom/core/exceptions.h>
#include <dom/core/string.h>
struct dom_event;
struct dom_document;
typedef struct dom_document dom_document_event;
/**
* The callback function which is used to process the default action of any
* event.
*
* As ::dom_default_action_phase defines, we have three points in our
* implementation where these kinds of callbacks get invoked.
*
* When the implementation start to dispatch certain event, it firstly invoke
* the following callback, which should process the event before the normal
* event flow.
*
* Take a MousePressed event on a check box object as example:
* 1. The 'pressed' event is generated by OS and catched by our UI code;
* 2. The UI code dispatch the event to DOM;
* 3. DOM trys to dispatch the event as what the spec said;
* 4. Before the real event flow happens, DOM get the
* dom_default_action_callback function from the
* dom_events_default_action_fetcher with param
* DOM_DEFAULT_ACTION_STARTED, and then call it;
* 5. The callback function invoke some System-denpendent API to make the
* checkbox checked and then return;
* 6. Normal event flow goes on.
* 7. When the implementation reach the end of the event flow, it check whether
* the event's default action is prevented, if it is, then go to step 8,
* else go to step 9.
* 8. The event's default action get prevented, DOM get the
* dom_default_action_callback function from the
* dom_events_default_action_fetcher with param
* DOM_DEFAULT_ACTION_PREVENTED, and then call it.
* 8. The event's default action does not get prevented, DOM get the
* dom_default_action_callback function from the
* dom_events_default_action_fetcher with param
* DOM_DEFAULT_ACTION_END, and then call it.
*
* @note: the point here is that we want the UI related stuff to be done
* within the default action code. The DOM only take care of the content tree
* and the event flow itself.
*/
typedef void (*dom_default_action_callback)(struct dom_event *evt, void *pw);
/**
* The default action phase
*
* @note: we define the following three values to fetch three different types
* of dom_default_action_callback function and their private data.
*/
typedef enum {
DOM_DEFAULT_ACTION_STARTED = 0,
DOM_DEFAULT_ACTION_PREVENTED,
DOM_DEFAULT_ACTION_END
} dom_default_action_phase;
/**
* The default action fetcher
*
* \param type The type of the event
* \param phase The phase of the default action callback
* \param pw The return private data of the callback function
* \return a callback function, NULL if there is none.
*/
typedef dom_default_action_callback (*dom_events_default_action_fetcher)
(dom_string *type, dom_default_action_phase phase,
void **pw);
dom_exception _dom_document_event_create_event(dom_document_event *de,
dom_string *type, struct dom_event **evt);
#define dom_document_event_create_event(d, t, e) \
_dom_document_event_create_event((dom_document_event *) (d), \
(dom_string *) (t), (struct dom_event **) (e))
dom_exception _dom_document_event_can_dispatch(dom_document_event *de,
dom_string *namespace, dom_string *type,
bool* can);
#define dom_document_event_can_dispatch(d, n, t, c) \
_dom_document_event_can_dispatch((dom_document_event *) (d), \
(dom_string *) (n), (dom_string *) (t),\
(bool *) (c))
#endif
|
