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1 : : /* GIO - GLib Input, Output and Streaming Library
2 : : *
3 : : * Copyright (C) 2009 Red Hat, Inc.
4 : : *
5 : : * SPDX-License-Identifier: LGPL-2.1-or-later
6 : : *
7 : : * This library is free software; you can redistribute it and/or
8 : : * modify it under the terms of the GNU Lesser General Public
9 : : * License as published by the Free Software Foundation; either
10 : : * version 2.1 of the License, or (at your option) any later version.
11 : : *
12 : : * This library is distributed in the hope that it will be useful,
13 : : * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 : : * Lesser General Public License for more details.
16 : : *
17 : : * You should have received a copy of the GNU Lesser General
18 : : * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
19 : : *
20 : : * Author: Alexander Larsson <alexl@redhat.com>
21 : : */
22 : :
23 : : #include "config.h"
24 : : #include "ginitable.h"
25 : : #include "glibintl.h"
26 : :
27 : :
28 : : /**
29 : : * GInitable:
30 : : *
31 : : * `GInitable` is implemented by objects that can fail during
32 : : * initialization. If an object implements this interface then
33 : : * it must be initialized as the first thing after construction,
34 : : * either via [method@Gio.Initable.init] or [method@Gio.AsyncInitable.init_async]
35 : : * (the latter is only available if it also implements [iface@Gio.AsyncInitable]).
36 : : *
37 : : * If the object is not initialized, or initialization returns with an
38 : : * error, then all operations on the object except `g_object_ref()` and
39 : : * `g_object_unref()` are considered to be invalid, and have undefined
40 : : * behaviour. They will often fail with [func@GLib.critical] or
41 : : * [func@GLib.warning], but this must not be relied on.
42 : : *
43 : : * Users of objects implementing this are not intended to use
44 : : * the interface method directly, instead it will be used automatically
45 : : * in various ways. For C applications you generally just call
46 : : * [func@Gio.Initable.new] directly, or indirectly via a `foo_thing_new()` wrapper.
47 : : * This will call [method@Gio.Initable.init] under the cover, returning `NULL`
48 : : * and setting a `GError` on failure (at which point the instance is
49 : : * unreferenced).
50 : : *
51 : : * For bindings in languages where the native constructor supports
52 : : * exceptions the binding could check for objects implementing `GInitable`
53 : : * during normal construction and automatically initialize them, throwing
54 : : * an exception on failure.
55 : : *
56 : : * Since: 2.22
57 : : */
58 : :
59 : : typedef GInitableIface GInitableInterface;
60 : 27494 : G_DEFINE_INTERFACE (GInitable, g_initable, G_TYPE_OBJECT)
61 : :
62 : : static void
63 : 146 : g_initable_default_init (GInitableInterface *iface)
64 : : {
65 : 146 : }
66 : :
67 : : /**
68 : : * g_initable_init:
69 : : * @initable: a #GInitable.
70 : : * @cancellable: optional #GCancellable object, %NULL to ignore.
71 : : * @error: a #GError location to store the error occurring, or %NULL to
72 : : * ignore.
73 : : *
74 : : * Initializes the object implementing the interface.
75 : : *
76 : : * This method is intended for language bindings. If writing in C,
77 : : * g_initable_new() should typically be used instead.
78 : : *
79 : : * The object must be initialized before any real use after initial
80 : : * construction, either with this function or g_async_initable_init_async().
81 : : *
82 : : * Implementations may also support cancellation. If @cancellable is not %NULL,
83 : : * then initialization can be cancelled by triggering the cancellable object
84 : : * from another thread. If the operation was cancelled, the error
85 : : * %G_IO_ERROR_CANCELLED will be returned. If @cancellable is not %NULL and
86 : : * the object doesn't support cancellable initialization the error
87 : : * %G_IO_ERROR_NOT_SUPPORTED will be returned.
88 : : *
89 : : * If the object is not initialized, or initialization returns with an
90 : : * error, then all operations on the object except g_object_ref() and
91 : : * g_object_unref() are considered to be invalid, and have undefined
92 : : * behaviour. See the [introduction][ginitable] for more details.
93 : : *
94 : : * Callers should not assume that a class which implements #GInitable can be
95 : : * initialized multiple times, unless the class explicitly documents itself as
96 : : * supporting this. Generally, a class’ implementation of init() can assume
97 : : * (and assert) that it will only be called once. Previously, this documentation
98 : : * recommended all #GInitable implementations should be idempotent; that
99 : : * recommendation was relaxed in GLib 2.54.
100 : : *
101 : : * If a class explicitly supports being initialized multiple times, it is
102 : : * recommended that the method is idempotent: multiple calls with the same
103 : : * arguments should return the same results. Only the first call initializes
104 : : * the object; further calls return the result of the first call.
105 : : *
106 : : * One reason why a class might need to support idempotent initialization is if
107 : : * it is designed to be used via the singleton pattern, with a
108 : : * #GObjectClass.constructor that sometimes returns an existing instance.
109 : : * In this pattern, a caller would expect to be able to call g_initable_init()
110 : : * on the result of g_object_new(), regardless of whether it is in fact a new
111 : : * instance.
112 : : *
113 : : * Returns: %TRUE if successful. If an error has occurred, this function will
114 : : * return %FALSE and set @error appropriately if present.
115 : : *
116 : : * Since: 2.22
117 : : */
118 : : gboolean
119 : 5909 : g_initable_init (GInitable *initable,
120 : : GCancellable *cancellable,
121 : : GError **error)
122 : : {
123 : : GInitableIface *iface;
124 : :
125 : 5909 : g_return_val_if_fail (G_IS_INITABLE (initable), FALSE);
126 : :
127 : 5909 : iface = G_INITABLE_GET_IFACE (initable);
128 : :
129 : 5909 : return (* iface->init) (initable, cancellable, error);
130 : : }
131 : :
132 : : /**
133 : : * g_initable_new:
134 : : * @object_type: a #GType supporting #GInitable.
135 : : * @cancellable: optional #GCancellable object, %NULL to ignore.
136 : : * @error: a #GError location to store the error occurring, or %NULL to
137 : : * ignore.
138 : : * @first_property_name: (nullable): the name of the first property, or %NULL if no
139 : : * properties
140 : : * @...: the value if the first property, followed by and other property
141 : : * value pairs, and ended by %NULL.
142 : : *
143 : : * Helper function for constructing #GInitable object. This is
144 : : * similar to g_object_new() but also initializes the object
145 : : * and returns %NULL, setting an error on failure.
146 : : *
147 : : * Returns: (type GObject.Object) (transfer full): a newly allocated
148 : : * #GObject, or %NULL on error
149 : : *
150 : : * Since: 2.22
151 : : */
152 : : gpointer
153 : 3493 : g_initable_new (GType object_type,
154 : : GCancellable *cancellable,
155 : : GError **error,
156 : : const gchar *first_property_name,
157 : : ...)
158 : : {
159 : : GObject *object;
160 : : va_list var_args;
161 : :
162 : 3493 : va_start (var_args, first_property_name);
163 : 3493 : object = g_initable_new_valist (object_type,
164 : : first_property_name, var_args,
165 : : cancellable, error);
166 : 3493 : va_end (var_args);
167 : :
168 : 3493 : return object;
169 : : }
170 : :
171 : : /**
172 : : * g_initable_newv:
173 : : * @object_type: a #GType supporting #GInitable.
174 : : * @n_parameters: the number of parameters in @parameters
175 : : * @parameters: (array length=n_parameters): the parameters to use to construct the object
176 : : * @cancellable: optional #GCancellable object, %NULL to ignore.
177 : : * @error: a #GError location to store the error occurring, or %NULL to
178 : : * ignore.
179 : : *
180 : : * Helper function for constructing #GInitable object. This is
181 : : * similar to g_object_newv() but also initializes the object
182 : : * and returns %NULL, setting an error on failure.
183 : : *
184 : : * Returns: (type GObject.Object) (transfer full): a newly allocated
185 : : * #GObject, or %NULL on error
186 : : *
187 : : * Since: 2.22
188 : : * Deprecated: 2.54: Use g_object_new_with_properties() and
189 : : * g_initable_init() instead. See #GParameter for more information.
190 : : */
191 : : G_GNUC_BEGIN_IGNORE_DEPRECATIONS
192 : : gpointer
193 : 0 : g_initable_newv (GType object_type,
194 : : guint n_parameters,
195 : : GParameter *parameters,
196 : : GCancellable *cancellable,
197 : : GError **error)
198 : : {
199 : : GObject *obj;
200 : :
201 : 0 : g_return_val_if_fail (G_TYPE_IS_INITABLE (object_type), NULL);
202 : :
203 : 0 : obj = g_object_newv (object_type, n_parameters, parameters);
204 : :
205 : 0 : if (!g_initable_init (G_INITABLE (obj), cancellable, error))
206 : : {
207 : 0 : g_object_unref (obj);
208 : 0 : return NULL;
209 : : }
210 : :
211 : 0 : return (gpointer)obj;
212 : : }
213 : : G_GNUC_END_IGNORE_DEPRECATIONS
214 : :
215 : : /**
216 : : * g_initable_new_valist:
217 : : * @object_type: a #GType supporting #GInitable.
218 : : * @first_property_name: the name of the first property, followed by
219 : : * the value, and other property value pairs, and ended by %NULL.
220 : : * @var_args: The var args list generated from @first_property_name.
221 : : * @cancellable: optional #GCancellable object, %NULL to ignore.
222 : : * @error: a #GError location to store the error occurring, or %NULL to
223 : : * ignore.
224 : : *
225 : : * Helper function for constructing #GInitable object. This is
226 : : * similar to g_object_new_valist() but also initializes the object
227 : : * and returns %NULL, setting an error on failure.
228 : : *
229 : : * Returns: (type GObject.Object) (transfer full): a newly allocated
230 : : * #GObject, or %NULL on error
231 : : *
232 : : * Since: 2.22
233 : : */
234 : : GObject*
235 : 3493 : g_initable_new_valist (GType object_type,
236 : : const gchar *first_property_name,
237 : : va_list var_args,
238 : : GCancellable *cancellable,
239 : : GError **error)
240 : : {
241 : : GObject *obj;
242 : :
243 : 3493 : g_return_val_if_fail (G_TYPE_IS_INITABLE (object_type), NULL);
244 : :
245 : 3493 : obj = g_object_new_valist (object_type,
246 : : first_property_name,
247 : : var_args);
248 : :
249 : 3493 : if (!g_initable_init (G_INITABLE (obj), cancellable, error))
250 : : {
251 : 88 : g_object_unref (obj);
252 : 88 : return NULL;
253 : : }
254 : :
255 : 3405 : return obj;
256 : : }
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