1 /* GIO - GLib Input, Output and Streaming Library
3 * Copyright (C) 2006-2007 Red Hat, Inc.
5 * SPDX-License-Identifier: LGPL-2.1-or-later
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.
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.
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/>.
20 * Author: Alexander Larsson <alexl@redhat.com>
26 #include <gfileinputstream.h>
27 #include <gseekable.h>
28 #include "gcancellable.h"
29 #include "gasyncresult.h"
38 * `GFileInputStream` provides input streams that take their
39 * content from a file.
41 * `GFileInputStream` implements [iface@Gio.Seekable], which allows the input
42 * stream to jump to arbitrary positions in the file, provided the
43 * filesystem of the file allows it. To find the position of a file
44 * input stream, use [method@Gio.Seekable.tell]. To find out if a file input
45 * stream supports seeking, use [vfunc@Gio.Seekable.can_seek].
46 * To position a file input stream, use [vfunc@Gio.Seekable.seek].
49 static void g_file_input_stream_seekable_iface_init (GSeekableIface *iface);
50 static goffset g_file_input_stream_seekable_tell (GSeekable *seekable);
51 static gboolean g_file_input_stream_seekable_can_seek (GSeekable *seekable);
52 static gboolean g_file_input_stream_seekable_seek (GSeekable *seekable,
55 GCancellable *cancellable,
57 static gboolean g_file_input_stream_seekable_can_truncate (GSeekable *seekable);
58 static gboolean g_file_input_stream_seekable_truncate (GSeekable *seekable,
60 GCancellable *cancellable,
62 static void g_file_input_stream_real_query_info_async (GFileInputStream *stream,
63 const char *attributes,
65 GCancellable *cancellable,
66 GAsyncReadyCallback callback,
68 static GFileInfo *g_file_input_stream_real_query_info_finish (GFileInputStream *stream,
73 struct _GFileInputStreamPrivate {
74 GAsyncReadyCallback outstanding_callback;
77 G_DEFINE_TYPE_WITH_CODE (GFileInputStream, g_file_input_stream, G_TYPE_INPUT_STREAM,
78 G_ADD_PRIVATE (GFileInputStream)
79 G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
80 g_file_input_stream_seekable_iface_init))
83 g_file_input_stream_class_init (GFileInputStreamClass *klass)
85 klass->query_info_async = g_file_input_stream_real_query_info_async;
86 klass->query_info_finish = g_file_input_stream_real_query_info_finish;
90 g_file_input_stream_seekable_iface_init (GSeekableIface *iface)
92 iface->tell = g_file_input_stream_seekable_tell;
93 iface->can_seek = g_file_input_stream_seekable_can_seek;
94 iface->seek = g_file_input_stream_seekable_seek;
95 iface->can_truncate = g_file_input_stream_seekable_can_truncate;
96 iface->truncate_fn = g_file_input_stream_seekable_truncate;
100 g_file_input_stream_init (GFileInputStream *stream)
102 stream->priv = g_file_input_stream_get_instance_private (stream);
106 * g_file_input_stream_query_info:
107 * @stream: a #GFileInputStream.
108 * @attributes: a file attribute query string.
109 * @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
110 * @error: a #GError location to store the error occurring, or %NULL to
113 * Queries a file input stream the given @attributes. This function blocks
114 * while querying the stream. For the asynchronous (non-blocking) version
115 * of this function, see g_file_input_stream_query_info_async(). While the
116 * stream is blocked, the stream will set the pending flag internally, and
117 * any other operations on the stream will fail with %G_IO_ERROR_PENDING.
119 * Returns: (transfer full): a #GFileInfo, or %NULL on error.
122 g_file_input_stream_query_info (GFileInputStream *stream,
123 const char *attributes,
124 GCancellable *cancellable,
127 GFileInputStreamClass *class;
128 GInputStream *input_stream;
131 g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
133 input_stream = G_INPUT_STREAM (stream);
135 if (!g_input_stream_set_pending (input_stream, error))
141 g_cancellable_push_current (cancellable);
143 class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
144 if (class->query_info)
145 info = class->query_info (stream, attributes, cancellable, error);
147 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
148 _("Stream doesn’t support query_info"));
151 g_cancellable_pop_current (cancellable);
153 g_input_stream_clear_pending (input_stream);
159 async_ready_callback_wrapper (GObject *source_object,
163 GFileInputStream *stream = G_FILE_INPUT_STREAM (source_object);
165 g_input_stream_clear_pending (G_INPUT_STREAM (stream));
166 if (stream->priv->outstanding_callback)
167 (*stream->priv->outstanding_callback) (source_object, res, user_data);
168 g_object_unref (stream);
172 * g_file_input_stream_query_info_async:
173 * @stream: a #GFileInputStream.
174 * @attributes: a file attribute query string.
175 * @io_priority: the [I/O priority][io-priority] of the request
176 * @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
177 * @callback: (scope async): a #GAsyncReadyCallback
178 * to call when the request is satisfied
179 * @user_data: the data to pass to callback function
181 * Queries the stream information asynchronously.
182 * When the operation is finished @callback will be called.
183 * You can then call g_file_input_stream_query_info_finish()
184 * to get the result of the operation.
186 * For the synchronous version of this function,
187 * see g_file_input_stream_query_info().
189 * If @cancellable is not %NULL, then the operation can be cancelled by
190 * triggering the cancellable object from another thread. If the operation
191 * was cancelled, the error %G_IO_ERROR_CANCELLED will be set
195 g_file_input_stream_query_info_async (GFileInputStream *stream,
196 const char *attributes,
198 GCancellable *cancellable,
199 GAsyncReadyCallback callback,
202 GFileInputStreamClass *klass;
203 GInputStream *input_stream;
204 GError *error = NULL;
206 g_return_if_fail (G_IS_FILE_INPUT_STREAM (stream));
208 input_stream = G_INPUT_STREAM (stream);
210 if (!g_input_stream_set_pending (input_stream, &error))
212 g_task_report_error (stream, callback, user_data,
213 g_file_input_stream_query_info_async,
218 klass = G_FILE_INPUT_STREAM_GET_CLASS (stream);
220 stream->priv->outstanding_callback = callback;
221 g_object_ref (stream);
222 klass->query_info_async (stream, attributes, io_priority, cancellable,
223 async_ready_callback_wrapper, user_data);
227 * g_file_input_stream_query_info_finish:
228 * @stream: a #GFileInputStream.
229 * @result: a #GAsyncResult.
230 * @error: a #GError location to store the error occurring,
231 * or %NULL to ignore.
233 * Finishes an asynchronous info query operation.
235 * Returns: (transfer full): #GFileInfo.
238 g_file_input_stream_query_info_finish (GFileInputStream *stream,
239 GAsyncResult *result,
242 GFileInputStreamClass *class;
244 g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
245 g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
247 if (g_async_result_legacy_propagate_error (result, error))
249 else if (g_async_result_is_tagged (result, g_file_input_stream_query_info_async))
250 return g_task_propagate_pointer (G_TASK (result), error);
252 class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
253 return class->query_info_finish (stream, result, error);
257 g_file_input_stream_tell (GFileInputStream *stream)
259 GFileInputStreamClass *class;
262 g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), 0);
264 class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
268 offset = class->tell (stream);
274 g_file_input_stream_seekable_tell (GSeekable *seekable)
276 return g_file_input_stream_tell (G_FILE_INPUT_STREAM (seekable));
280 g_file_input_stream_can_seek (GFileInputStream *stream)
282 GFileInputStreamClass *class;
285 g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
287 class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
294 can_seek = class->can_seek (stream);
301 g_file_input_stream_seekable_can_seek (GSeekable *seekable)
303 return g_file_input_stream_can_seek (G_FILE_INPUT_STREAM (seekable));
307 g_file_input_stream_seek (GFileInputStream *stream,
310 GCancellable *cancellable,
313 GFileInputStreamClass *class;
314 GInputStream *input_stream;
317 g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
319 input_stream = G_INPUT_STREAM (stream);
320 class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
324 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
325 _("Seek not supported on stream"));
329 if (!g_input_stream_set_pending (input_stream, error))
333 g_cancellable_push_current (cancellable);
335 res = class->seek (stream, offset, type, cancellable, error);
338 g_cancellable_pop_current (cancellable);
340 g_input_stream_clear_pending (input_stream);
346 g_file_input_stream_seekable_seek (GSeekable *seekable,
349 GCancellable *cancellable,
352 return g_file_input_stream_seek (G_FILE_INPUT_STREAM (seekable),
353 offset, type, cancellable, error);
357 g_file_input_stream_seekable_can_truncate (GSeekable *seekable)
363 g_file_input_stream_seekable_truncate (GSeekable *seekable,
365 GCancellable *cancellable,
368 g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
369 _("Truncate not allowed on input stream"));
373 /********************************************
374 * Default implementation of async ops *
375 ********************************************/
378 query_info_async_thread (GTask *task,
379 gpointer source_object,
381 GCancellable *cancellable)
383 GFileInputStream *stream = source_object;
384 const char *attributes = task_data;
385 GFileInputStreamClass *class;
386 GError *error = NULL;
387 GFileInfo *info = NULL;
389 class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
390 if (class->query_info)
391 info = class->query_info (stream, attributes, cancellable, &error);
393 g_set_error_literal (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
394 _("Stream doesn’t support query_info"));
397 g_task_return_error (task, error);
399 g_task_return_pointer (task, info, g_object_unref);
403 g_file_input_stream_real_query_info_async (GFileInputStream *stream,
404 const char *attributes,
406 GCancellable *cancellable,
407 GAsyncReadyCallback callback,
412 task = g_task_new (stream, cancellable, callback, user_data);
413 g_task_set_source_tag (task, g_file_input_stream_real_query_info_async);
414 g_task_set_task_data (task, g_strdup (attributes), g_free);
415 g_task_set_priority (task, io_priority);
417 g_task_run_in_thread (task, query_info_async_thread);
418 g_object_unref (task);
422 g_file_input_stream_real_query_info_finish (GFileInputStream *stream,
426 g_return_val_if_fail (g_task_is_valid (res, stream), NULL);
428 return g_task_propagate_pointer (G_TASK (res), error);