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
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/* GObject - GLib Type, Object, Parameter and Signal Library
* Copyright (C) 2000 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "gtypeplugin.h"
/**
* SECTION:gtypeplugin
* @short_description: An interface for dynamically loadable types
* @see_also: #GTypeModule and g_type_register_dynamic().
* @title: GTypePlugin
*
* An interface that handles the lifecycle of dynamically loaded types.
*
* The GObject type system supports dynamic loading of types.
* It goes as follows:
*
* 1. The type is initially introduced (usually upon loading the module
* the first time, or by your main application that knows what modules
* introduces what types), like this:
* |[<!-- language="C" -->
* new_type_id = g_type_register_dynamic (parent_type_id,
* "TypeName",
* new_type_plugin,
* type_flags);
* ]|
* where @new_type_plugin is an implementation of the
* #GTypePlugin interface.
*
* 2. The type's implementation is referenced, e.g. through
* g_type_class_ref() or through g_type_create_instance() (this is
* being called by g_object_new()) or through one of the above done on
* a type derived from @new_type_id.
*
* 3. This causes the type system to load the type's implementation by
* calling g_type_plugin_use() and g_type_plugin_complete_type_info()
* on @new_type_plugin.
*
* 4. At some point the type's implementation isn't required anymore,
* e.g. after g_type_class_unref() or g_type_free_instance() (called
* when the reference count of an instance drops to zero).
*
* 5. This causes the type system to throw away the information retrieved
* from g_type_plugin_complete_type_info() and then it calls
* g_type_plugin_unuse() on @new_type_plugin.
*
* 6. Things may repeat from the second step.
*
* So basically, you need to implement a #GTypePlugin type that
* carries a use_count, once use_count goes from zero to one, you need
* to load the implementation to successfully handle the upcoming
* g_type_plugin_complete_type_info() call. Later, maybe after
* succeeding use/unuse calls, once use_count drops to zero, you can
* unload the implementation again. The type system makes sure to call
* g_type_plugin_use() and g_type_plugin_complete_type_info() again
* when the type is needed again.
*
* #GTypeModule is an implementation of #GTypePlugin that already
* implements most of this except for the actual module loading and
* unloading. It even handles multiple registered types per module.
*/
/* --- functions --- */
GType
g_type_plugin_get_type (void)
{
static GType type_plugin_type = 0;
if (!type_plugin_type)
{
const GTypeInfo type_plugin_info = {
sizeof (GTypePluginClass),
NULL, /* base_init */
NULL, /* base_finalize */
0, /* class_init */
NULL, /* class_destroy */
NULL, /* class_data */
0, /* instance_size */
0, /* n_preallocs */
NULL, /* instance_init */
NULL, /* value_table */
};
type_plugin_type = g_type_register_static (G_TYPE_INTERFACE, g_intern_static_string ("GTypePlugin"), &type_plugin_info, 0);
}
return type_plugin_type;
}
/**
* g_type_plugin_use:
* @plugin: a #GTypePlugin
*
* Calls the @use_plugin function from the #GTypePluginClass of
* @plugin. There should be no need to use this function outside of
* the GObject type system itself.
*/
void
g_type_plugin_use (GTypePlugin *plugin)
{
GTypePluginClass *iface;
g_return_if_fail (G_IS_TYPE_PLUGIN (plugin));
iface = G_TYPE_PLUGIN_GET_CLASS (plugin);
iface->use_plugin (plugin);
}
/**
* g_type_plugin_unuse:
* @plugin: a #GTypePlugin
*
* Calls the @unuse_plugin function from the #GTypePluginClass of
* @plugin. There should be no need to use this function outside of
* the GObject type system itself.
*/
void
g_type_plugin_unuse (GTypePlugin *plugin)
{
GTypePluginClass *iface;
g_return_if_fail (G_IS_TYPE_PLUGIN (plugin));
iface = G_TYPE_PLUGIN_GET_CLASS (plugin);
iface->unuse_plugin (plugin);
}
/**
* g_type_plugin_complete_type_info:
* @plugin: a #GTypePlugin
* @g_type: the #GType whose info is completed
* @info: the #GTypeInfo struct to fill in
* @value_table: the #GTypeValueTable to fill in
*
* Calls the @complete_type_info function from the #GTypePluginClass of @plugin.
* There should be no need to use this function outside of the GObject
* type system itself.
*/
void
g_type_plugin_complete_type_info (GTypePlugin *plugin,
GType g_type,
GTypeInfo *info,
GTypeValueTable *value_table)
{
GTypePluginClass *iface;
g_return_if_fail (G_IS_TYPE_PLUGIN (plugin));
g_return_if_fail (info != NULL);
g_return_if_fail (value_table != NULL);
iface = G_TYPE_PLUGIN_GET_CLASS (plugin);
iface->complete_type_info (plugin,
g_type,
info,
value_table);
}
/**
* g_type_plugin_complete_interface_info:
* @plugin: the #GTypePlugin
* @instance_type: the #GType of an instantiatable type to which the interface
* is added
* @interface_type: the #GType of the interface whose info is completed
* @info: the #GInterfaceInfo to fill in
*
* Calls the @complete_interface_info function from the
* #GTypePluginClass of @plugin. There should be no need to use this
* function outside of the GObject type system itself.
*/
void
g_type_plugin_complete_interface_info (GTypePlugin *plugin,
GType instance_type,
GType interface_type,
GInterfaceInfo *info)
{
GTypePluginClass *iface;
g_return_if_fail (G_IS_TYPE_PLUGIN (plugin));
g_return_if_fail (info != NULL);
iface = G_TYPE_PLUGIN_GET_CLASS (plugin);
iface->complete_interface_info (plugin,
instance_type,
interface_type,
info);
}
|
