/src/irssi/subprojects/glib-2.74.7/gio/gpollableinputstream.c

Source
/* GIO - GLib Input, Output and Streaming Library
 *
 * Copyright (C) 2010 Red Hat, Inc.
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * 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 <errno.h>

#include "gpollableinputstream.h"
#include "gasynchelper.h"
#include "glibintl.h"

/**
 * SECTION:gpollableinputstream
 * @short_description: Interface for pollable input streams
 * @include: gio/gio.h
 * @see_also: #GInputStream, #GPollableOutputStream, #GFileDescriptorBased
 *
 * #GPollableInputStream is implemented by #GInputStreams that
 * can be polled for readiness to read. This can be used when
 * interfacing with a non-GIO API that expects
 * UNIX-file-descriptor-style asynchronous I/O rather than GIO-style.
 *
 * Since: 2.28
 */

G_DEFINE_INTERFACE (GPollableInputStream, g_pollable_input_stream, G_TYPE_INPUT_STREAM)

static gboolean g_pollable_input_stream_default_can_poll         (GPollableInputStream *stream);
static gssize   g_pollable_input_stream_default_read_nonblocking (GPollableInputStream  *stream,
                  void                  *buffer,
                  gsize                  count,
                  GError               **error);

static void
g_pollable_input_stream_default_init (GPollableInputStreamInterface *iface)
{
  iface->can_poll         = g_pollable_input_stream_default_can_poll;
  iface->read_nonblocking = g_pollable_input_stream_default_read_nonblocking;
}

static gboolean
g_pollable_input_stream_default_can_poll (GPollableInputStream *stream)
{
  return TRUE;
}

/**
 * g_pollable_input_stream_can_poll:
 * @stream: a #GPollableInputStream.
 *
 * Checks if @stream is actually pollable. Some classes may implement
 * #GPollableInputStream but have only certain instances of that class
 * be pollable. If this method returns %FALSE, then the behavior of
 * other #GPollableInputStream methods is undefined.
 *
 * For any given stream, the value returned by this method is constant;
 * a stream cannot switch from pollable to non-pollable or vice versa.
 *
 * Returns: %TRUE if @stream is pollable, %FALSE if not.
 *
 * Since: 2.28
 */
gboolean
g_pollable_input_stream_can_poll (GPollableInputStream *stream)
{
  g_return_val_if_fail (G_IS_POLLABLE_INPUT_STREAM (stream), FALSE);

  return G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->can_poll (stream);
}

/**
 * g_pollable_input_stream_is_readable:
 * @stream: a #GPollableInputStream.
 *
 * Checks if @stream can be read.
 *
 * Note that some stream types may not be able to implement this 100%
 * reliably, and it is possible that a call to g_input_stream_read()
 * after this returns %TRUE would still block. To guarantee
 * non-blocking behavior, you should always use
 * g_pollable_input_stream_read_nonblocking(), which will return a
 * %G_IO_ERROR_WOULD_BLOCK error rather than blocking.
 *
 * Returns: %TRUE if @stream is readable, %FALSE if not. If an error
 *   has occurred on @stream, this will result in
 *   g_pollable_input_stream_is_readable() returning %TRUE, and the
 *   next attempt to read will return the error.
 *
 * Since: 2.28
 */
gboolean
g_pollable_input_stream_is_readable (GPollableInputStream *stream)
{
  g_return_val_if_fail (G_IS_POLLABLE_INPUT_STREAM (stream), FALSE);

  return G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->is_readable (stream);
}

/**
 * g_pollable_input_stream_create_source:
 * @stream: a #GPollableInputStream.
 * @cancellable: (nullable): a #GCancellable, or %NULL
 *
 * Creates a #GSource that triggers when @stream can be read, or
 * @cancellable is triggered or an error occurs. The callback on the
 * source is of the #GPollableSourceFunc type.
 *
 * As with g_pollable_input_stream_is_readable(), it is possible that
 * the stream may not actually be readable even after the source
 * triggers, so you should use g_pollable_input_stream_read_nonblocking()
 * rather than g_input_stream_read() from the callback.
 *
 * Returns: (transfer full): a new #GSource
 *
 * Since: 2.28
 */
GSource *
g_pollable_input_stream_create_source (GPollableInputStream *stream,
               GCancellable         *cancellable)
{
  g_return_val_if_fail (G_IS_POLLABLE_INPUT_STREAM (stream), NULL);

  return G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->
    create_source (stream, cancellable);
}

static gssize
g_pollable_input_stream_default_read_nonblocking (GPollableInputStream  *stream,
              void                  *buffer,
              gsize                  count,
              GError               **error)
{
  if (!g_pollable_input_stream_is_readable (stream))
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK,
                           g_strerror (EAGAIN));
      return -1;
    }

  return G_INPUT_STREAM_GET_CLASS (stream)->
    read_fn (G_INPUT_STREAM (stream), buffer, count, NULL, error);
}

/**
 * g_pollable_input_stream_read_nonblocking:
 * @stream: a #GPollableInputStream
 * @buffer: (array length=count) (element-type guint8) (out caller-allocates): a
 *     buffer to read data into (which should be at least @count bytes long).
 * @count: (in): the number of bytes you want to read
 * @cancellable: (nullable): a #GCancellable, or %NULL
 * @error: #GError for error reporting, or %NULL to ignore.
 *
 * Attempts to read up to @count bytes from @stream into @buffer, as
 * with g_input_stream_read(). If @stream is not currently readable,
 * this will immediately return %G_IO_ERROR_WOULD_BLOCK, and you can
 * use g_pollable_input_stream_create_source() to create a #GSource
 * that will be triggered when @stream is readable.
 *
 * Note that since this method never blocks, you cannot actually
 * use @cancellable to cancel it. However, it will return an error
 * if @cancellable has already been cancelled when you call, which
 * may happen if you call this method after a source triggers due
 * to having been cancelled.
 *
 * Virtual: read_nonblocking
 * Returns: the number of bytes read, or -1 on error (including
 *   %G_IO_ERROR_WOULD_BLOCK).
 */
gssize
g_pollable_input_stream_read_nonblocking (GPollableInputStream  *stream,
            void                  *buffer,
            gsize                  count,
            GCancellable          *cancellable,
            GError               **error)
{
  gssize res;

  g_return_val_if_fail (G_IS_POLLABLE_INPUT_STREAM (stream), -1);
  g_return_val_if_fail (buffer != NULL, 0);

  if (g_cancellable_set_error_if_cancelled (cancellable, error))
    return -1;

  if (count == 0)
    return 0;

  if (((gssize) count) < 0)
    {
      g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
       _("Too large count value passed to %s"), G_STRFUNC);
      return -1;
    }

  if (cancellable)
    g_cancellable_push_current (cancellable);

  res = G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->
    read_nonblocking (stream, buffer, count, error);

  if (cancellable)
    g_cancellable_pop_current (cancellable);

  return res;
}

Coverage Report

Created: 2026-07-16 06:32

Line	Count	Source
1		/* GIO - GLib Input, Output and Streaming Library
2		*
3		* Copyright (C) 2010 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
21		#include "config.h"
22
23		#include <errno.h>
24
25		#include "gpollableinputstream.h"
26		#include "gasynchelper.h"
27		#include "glibintl.h"
28
29		/**
30		* SECTION:gpollableinputstream
31		* @short_description: Interface for pollable input streams
32		* @include: gio/gio.h
33		* @see_also: #GInputStream, #GPollableOutputStream, #GFileDescriptorBased
34		*
35		* #GPollableInputStream is implemented by #GInputStreams that
36		* can be polled for readiness to read. This can be used when
37		* interfacing with a non-GIO API that expects
38		* UNIX-file-descriptor-style asynchronous I/O rather than GIO-style.
39		*
40		* Since: 2.28
41		*/
42
43	0	G_DEFINE_INTERFACE (GPollableInputStream, g_pollable_input_stream, G_TYPE_INPUT_STREAM)
44	0
45	0	static gboolean g_pollable_input_stream_default_can_poll (GPollableInputStream *stream);
46	0	static gssize g_pollable_input_stream_default_read_nonblocking (GPollableInputStream *stream,
47	0	void *buffer,
48	0	gsize count,
49	0	GError **error);
50	0
51	0	static void
52	0	g_pollable_input_stream_default_init (GPollableInputStreamInterface *iface)
53	0	{
54	0	iface->can_poll = g_pollable_input_stream_default_can_poll;
55	0	iface->read_nonblocking = g_pollable_input_stream_default_read_nonblocking;
56	0	}
57
58		static gboolean
59		g_pollable_input_stream_default_can_poll (GPollableInputStream *stream)
60	0	{
61	0	return TRUE;
62	0	}
63
64		/**
65		* g_pollable_input_stream_can_poll:
66		* @stream: a #GPollableInputStream.
67		*
68		* Checks if @stream is actually pollable. Some classes may implement
69		* #GPollableInputStream but have only certain instances of that class
70		* be pollable. If this method returns %FALSE, then the behavior of
71		* other #GPollableInputStream methods is undefined.
72		*
73		* For any given stream, the value returned by this method is constant;
74		* a stream cannot switch from pollable to non-pollable or vice versa.
75		*
76		* Returns: %TRUE if @stream is pollable, %FALSE if not.
77		*
78		* Since: 2.28
79		*/
80		gboolean
81		g_pollable_input_stream_can_poll (GPollableInputStream *stream)
82	0	{
83	0	g_return_val_if_fail (G_IS_POLLABLE_INPUT_STREAM (stream), FALSE);
84
85	0	return G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->can_poll (stream);
86	0	}
87
88		/**
89		* g_pollable_input_stream_is_readable:
90		* @stream: a #GPollableInputStream.
91		*
92		* Checks if @stream can be read.
93		*
94		* Note that some stream types may not be able to implement this 100%
95		* reliably, and it is possible that a call to g_input_stream_read()
96		* after this returns %TRUE would still block. To guarantee
97		* non-blocking behavior, you should always use
98		* g_pollable_input_stream_read_nonblocking(), which will return a
99		* %G_IO_ERROR_WOULD_BLOCK error rather than blocking.
100		*
101		* Returns: %TRUE if @stream is readable, %FALSE if not. If an error
102		* has occurred on @stream, this will result in
103		* g_pollable_input_stream_is_readable() returning %TRUE, and the
104		* next attempt to read will return the error.
105		*
106		* Since: 2.28
107		*/
108		gboolean
109		g_pollable_input_stream_is_readable (GPollableInputStream *stream)
110	0	{
111	0	g_return_val_if_fail (G_IS_POLLABLE_INPUT_STREAM (stream), FALSE);
112
113	0	return G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->is_readable (stream);
114	0	}
115
116		/**
117		* g_pollable_input_stream_create_source:
118		* @stream: a #GPollableInputStream.
119		* @cancellable: (nullable): a #GCancellable, or %NULL
120		*
121		* Creates a #GSource that triggers when @stream can be read, or
122		* @cancellable is triggered or an error occurs. The callback on the
123		* source is of the #GPollableSourceFunc type.
124		*
125		* As with g_pollable_input_stream_is_readable(), it is possible that
126		* the stream may not actually be readable even after the source
127		* triggers, so you should use g_pollable_input_stream_read_nonblocking()
128		* rather than g_input_stream_read() from the callback.
129		*
130		* Returns: (transfer full): a new #GSource
131		*
132		* Since: 2.28
133		*/
134		GSource *
135		g_pollable_input_stream_create_source (GPollableInputStream *stream,
136		GCancellable *cancellable)
137	0	{
138	0	g_return_val_if_fail (G_IS_POLLABLE_INPUT_STREAM (stream), NULL);
139
140	0	return G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->
141	0	create_source (stream, cancellable);
142	0	}
143
144		static gssize
145		g_pollable_input_stream_default_read_nonblocking (GPollableInputStream *stream,
146		void *buffer,
147		gsize count,
148		GError **error)
149	0	{
150	0	if (!g_pollable_input_stream_is_readable (stream))
151	0	{
152	0	g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK,
153	0	g_strerror (EAGAIN));
154	0	return -1;
155	0	}
156
157	0	return G_INPUT_STREAM_GET_CLASS (stream)->
158	0	read_fn (G_INPUT_STREAM (stream), buffer, count, NULL, error);
159	0	}
160
161		/**
162		* g_pollable_input_stream_read_nonblocking:
163		* @stream: a #GPollableInputStream
164		* @buffer: (array length=count) (element-type guint8) (out caller-allocates): a
165		* buffer to read data into (which should be at least @count bytes long).
166		* @count: (in): the number of bytes you want to read
167		* @cancellable: (nullable): a #GCancellable, or %NULL
168		* @error: #GError for error reporting, or %NULL to ignore.
169		*
170		* Attempts to read up to @count bytes from @stream into @buffer, as
171		* with g_input_stream_read(). If @stream is not currently readable,
172		* this will immediately return %G_IO_ERROR_WOULD_BLOCK, and you can
173		* use g_pollable_input_stream_create_source() to create a #GSource
174		* that will be triggered when @stream is readable.
175		*
176		* Note that since this method never blocks, you cannot actually
177		* use @cancellable to cancel it. However, it will return an error
178		* if @cancellable has already been cancelled when you call, which
179		* may happen if you call this method after a source triggers due
180		* to having been cancelled.
181		*
182		* Virtual: read_nonblocking
183		* Returns: the number of bytes read, or -1 on error (including
184		* %G_IO_ERROR_WOULD_BLOCK).
185		*/
186		gssize
187		g_pollable_input_stream_read_nonblocking (GPollableInputStream *stream,
188		void *buffer,
189		gsize count,
190		GCancellable *cancellable,
191		GError **error)
192	0	{
193	0	gssize res;
194
195	0	g_return_val_if_fail (G_IS_POLLABLE_INPUT_STREAM (stream), -1);
196	0	g_return_val_if_fail (buffer != NULL, 0);
197
198	0	if (g_cancellable_set_error_if_cancelled (cancellable, error))
199	0	return -1;
200
201	0	if (count == 0)
202	0	return 0;
203
204	0	if (((gssize) count) < 0)
205	0	{
206	0	g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
207	0	_("Too large count value passed to %s"), G_STRFUNC);
208	0	return -1;
209	0	}
210
211	0	if (cancellable)
212	0	g_cancellable_push_current (cancellable);
213
214	0	res = G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->
215	0	read_nonblocking (stream, buffer, count, error);
216
217	0	if (cancellable)
218	0	g_cancellable_pop_current (cancellable);
219
220	0	return res;
221	0	}