luc14n0/glib
1
0
Fork 0
mirror of https://gitlab.gnome.org/GNOME/glib.git synced 2024-12-27 07:56:14 +01:00
Code Issues Packages Projects Releases Wiki Activity
d906f84a44
glib/gio/ginputstream.c
Dan Winship 82d914d808 gio: add g_async_result_is_tagged() 
Rather than doing a two step first-check-the-GAsyncResult-subtype-then-
check-the-tag, add a GAsyncResult-level method so that you can do them
both at once, simplifying the code for "short-circuit" async return
values where the vmethod never gets called.

https://bugzilla.gnome.org/show_bug.cgi?id=661767
2012-07-10 10:49:20 -04:00

1440 lines
43 KiB
C
Raw Blame History

/* GIO - GLib Input, Output and Streaming Library
*
* Copyright (C) 2006-2007 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 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, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* Author: Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
#include <glib.h>
#include "glibintl.h"
#include "ginputstream.h"
#include "gseekable.h"
#include "gcancellable.h"
#include "gasyncresult.h"
#include "gsimpleasyncresult.h"
#include "gioerror.h"
#include "gpollableinputstream.h"
/**
* SECTION:ginputstream
* @short_description: Base class for implementing streaming input
* @include: gio/gio.h
*
* #GInputStream has functions to read from a stream (g_input_stream_read()),
* to close a stream (g_input_stream_close()) and to skip some content
* (g_input_stream_skip()).
*
* To copy the content of an input stream to an output stream without
* manually handling the reads and writes, use g_output_stream_splice().
*
* All of these functions have async variants too.
**/
G_DEFINE_ABSTRACT_TYPE (GInputStream, g_input_stream, G_TYPE_OBJECT);
struct _GInputStreamPrivate {
guint closed : 1;
guint pending : 1;
GAsyncReadyCallback outstanding_callback;
};
static gssize g_input_stream_real_skip (GInputStream *stream,
gsize count,
GCancellable *cancellable,
GError **error);
static void g_input_stream_real_read_async (GInputStream *stream,
void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
static gssize g_input_stream_real_read_finish (GInputStream *stream,
GAsyncResult *result,
GError **error);
static void g_input_stream_real_skip_async (GInputStream *stream,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gssize g_input_stream_real_skip_finish (GInputStream *stream,
GAsyncResult *result,
GError **error);
static void g_input_stream_real_close_async (GInputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer data);
static gboolean g_input_stream_real_close_finish (GInputStream *stream,
GAsyncResult *result,
GError **error);
static void
g_input_stream_finalize (GObject *object)
{
G_OBJECT_CLASS (g_input_stream_parent_class)->finalize (object);
}
static void
g_input_stream_dispose (GObject *object)
{
GInputStream *stream;
stream = G_INPUT_STREAM (object);
if (!stream->priv->closed)
g_input_stream_close (stream, NULL, NULL);
G_OBJECT_CLASS (g_input_stream_parent_class)->dispose (object);
}
static void
g_input_stream_class_init (GInputStreamClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
g_type_class_add_private (klass, sizeof (GInputStreamPrivate));
gobject_class->finalize = g_input_stream_finalize;
gobject_class->dispose = g_input_stream_dispose;
klass->skip = g_input_stream_real_skip;
klass->read_async = g_input_stream_real_read_async;
klass->read_finish = g_input_stream_real_read_finish;
klass->skip_async = g_input_stream_real_skip_async;
klass->skip_finish = g_input_stream_real_skip_finish;
klass->close_async = g_input_stream_real_close_async;
klass->close_finish = g_input_stream_real_close_finish;
}
static void
g_input_stream_init (GInputStream *stream)
{
stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
G_TYPE_INPUT_STREAM,
GInputStreamPrivate);
}
/**
* g_input_stream_read:
* @stream: a #GInputStream.
* @buffer: a buffer to read data into (which should be at least count bytes long).
* @count: the number of bytes that will be read from the stream
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to read @count bytes from the stream into the buffer starting at
* @buffer. Will block during this read.
*
* If count is zero returns zero and does nothing. A value of @count
* larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, the number of bytes read into the buffer is returned.
* It is not an error if this is not the same as the requested size, as it
* can happen e.g. near the end of a file. Zero is returned on end of file
* (or if @count is zero), but never otherwise.
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
* operation was partially finished when the operation was cancelled the
* partial result will be returned, without an error.
*
* On error -1 is returned and @error is set accordingly.
*
* Return value: Number of bytes read, or -1 on error, or 0 on end of file.
**/
gssize
g_input_stream_read (GInputStream *stream,
void *buffer,
gsize count,
GCancellable *cancellable,
GError **error)
{
GInputStreamClass *class;
gssize res;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), -1);
g_return_val_if_fail (buffer != NULL, 0);
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;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
if (class->read_fn == NULL)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
_("Input stream doesn't implement read"));
return -1;
}
if (!g_input_stream_set_pending (stream, error))
return -1;
if (cancellable)
g_cancellable_push_current (cancellable);
res = class->read_fn (stream, buffer, count, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_input_stream_clear_pending (stream);
return res;
}
/**
* g_input_stream_read_all:
* @stream: a #GInputStream.
* @buffer: a buffer to read data into (which should be at least count bytes long).
* @count: the number of bytes that will be read from the stream
* @bytes_read: (out): location to store the number of bytes that was read from the stream
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to read @count bytes from the stream into the buffer starting at
* @buffer. Will block during this read.
*
* This function is similar to g_input_stream_read(), except it tries to
* read as many bytes as requested, only stopping on an error or end of stream.
*
* On a successful read of @count bytes, or if we reached the end of the
* stream, %TRUE is returned, and @bytes_read is set to the number of bytes
* read into @buffer.
*
* If there is an error during the operation %FALSE is returned and @error
* is set to indicate the error status, @bytes_read is updated to contain
* the number of bytes read into @buffer before the error occurred.
*
* Return value: %TRUE on success, %FALSE if there was an error
**/
gboolean
g_input_stream_read_all (GInputStream *stream,
void *buffer,
gsize count,
gsize *bytes_read,
GCancellable *cancellable,
GError **error)
{
gsize _bytes_read;
gssize res;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
g_return_val_if_fail (buffer != NULL, FALSE);
_bytes_read = 0;
while (_bytes_read < count)
{
res = g_input_stream_read (stream, (char *)buffer + _bytes_read, count - _bytes_read,
cancellable, error);
if (res == -1)
{
if (bytes_read)
*bytes_read = _bytes_read;
return FALSE;
}
if (res == 0)
break;
_bytes_read += res;
}
if (bytes_read)
*bytes_read = _bytes_read;
return TRUE;
}
/**
* g_input_stream_read_bytes:
* @stream: a #GInputStream.
* @count: maximum number of bytes that will be read from the stream. Common
* values include 4096 and 8192.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Like g_input_stream_read(), this tries to read @count bytes from
* the stream in a blocking fashion. However, rather than reading into
* a user-supplied buffer, this will create a new #GBytes containing
* the data that was read. This may be easier to use from language
* bindings.
*
* If count is zero, returns a zero-length #GBytes and does nothing. A
* value of @count larger than %G_MAXSSIZE will cause a
* %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, a new #GBytes is returned. It is not an error if the
* size of this object is not the same as the requested size, as it
* can happen e.g. near the end of a file. A zero-length #GBytes is
* returned on end of file (or if @count is zero), but never
* otherwise.
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
* operation was partially finished when the operation was cancelled the
* partial result will be returned, without an error.
*
* On error %NULL is returned and @error is set accordingly.
*
* Return value: a new #GBytes, or %NULL on error
**/
GBytes *
g_input_stream_read_bytes (GInputStream *stream,
gsize count,
GCancellable *cancellable,
GError **error)
{
guchar *buf;
gssize nread;
buf = g_malloc (count);
nread = g_input_stream_read (stream, buf, count, cancellable, error);
if (nread == -1)
{
g_free (buf);
return NULL;
}
else if (nread == 0)
{
g_free (buf);
return g_bytes_new_static ("", 0);
}
else
return g_bytes_new_take (buf, nread);
}
/**
* g_input_stream_skip:
* @stream: a #GInputStream.
* @count: the number of bytes that will be skipped from the stream
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Tries to skip @count bytes from the stream. Will block during the operation.
*
* This is identical to g_input_stream_read(), from a behaviour standpoint,
* but the bytes that are skipped are not returned to the user. Some
* streams have an implementation that is more efficient than reading the data.
*
* This function is optional for inherited classes, as the default implementation
* emulates it using read.
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
* operation was partially finished when the operation was cancelled the
* partial result will be returned, without an error.
*
* Return value: Number of bytes skipped, or -1 on error
**/
gssize
g_input_stream_skip (GInputStream *stream,
gsize count,
GCancellable *cancellable,
GError **error)
{
GInputStreamClass *class;
gssize res;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), -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;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
if (!g_input_stream_set_pending (stream, error))
return -1;
if (cancellable)
g_cancellable_push_current (cancellable);
res = class->skip (stream, count, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_input_stream_clear_pending (stream);
return res;
}
static gssize
g_input_stream_real_skip (GInputStream *stream,
gsize count,
GCancellable *cancellable,
GError **error)
{
GInputStreamClass *class;
gssize ret, read_bytes;
char buffer[8192];
GError *my_error;
if (G_IS_SEEKABLE (stream) && g_seekable_can_seek (G_SEEKABLE (stream)))
{
if (g_seekable_seek (G_SEEKABLE (stream),
count,
G_SEEK_CUR,
cancellable,
NULL))
return count;
}
/* If not seekable, or seek failed, fall back to reading data: */
class = G_INPUT_STREAM_GET_CLASS (stream);
read_bytes = 0;
while (1)
{
my_error = NULL;
ret = class->read_fn (stream, buffer, MIN (sizeof (buffer), count),
cancellable, &my_error);
if (ret == -1)
{
if (read_bytes > 0 &&
my_error->domain == G_IO_ERROR &&
my_error->code == G_IO_ERROR_CANCELLED)
{
g_error_free (my_error);
return read_bytes;
}
g_propagate_error (error, my_error);
return -1;
}
count -= ret;
read_bytes += ret;
if (ret == 0 || count == 0)
return read_bytes;
}
}
/**
* g_input_stream_close:
* @stream: A #GInputStream.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* Closes the stream, releasing resources related to it.
*
* Once the stream is closed, all other operations will return %G_IO_ERROR_CLOSED.
* Closing a stream multiple times will not return an error.
*
* Streams will be automatically closed when the last reference
* is dropped, but you might want to call this function to make sure
* resources are released as early as possible.
*
* Some streams might keep the backing store of the stream (e.g. a file descriptor)
* open after the stream is closed. See the documentation for the individual
* stream for details.
*
* On failure the first error that happened will be reported, but the close
* operation will finish as much as possible. A stream that failed to
* close will still return %G_IO_ERROR_CLOSED for all operations. Still, it
* is important to check and report the error to the user.
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
* Cancelling a close will still leave the stream closed, but some streams
* can use a faster close that doesn't block to e.g. check errors.
*
* Return value: %TRUE on success, %FALSE on failure
**/
gboolean
g_input_stream_close (GInputStream *stream,
GCancellable *cancellable,
GError **error)
{
GInputStreamClass *class;
gboolean res;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
class = G_INPUT_STREAM_GET_CLASS (stream);
if (stream->priv->closed)
return TRUE;
res = TRUE;
if (!g_input_stream_set_pending (stream, error))
return FALSE;
if (cancellable)
g_cancellable_push_current (cancellable);
if (class->close_fn)
res = class->close_fn (stream, cancellable, error);
if (cancellable)
g_cancellable_pop_current (cancellable);
g_input_stream_clear_pending (stream);
stream->priv->closed = TRUE;
return res;
}
static void
async_ready_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GInputStream *stream = G_INPUT_STREAM (source_object);
g_input_stream_clear_pending (stream);
if (stream->priv->outstanding_callback)
(*stream->priv->outstanding_callback) (source_object, res, user_data);
g_object_unref (stream);
}
static void
async_ready_close_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GInputStream *stream = G_INPUT_STREAM (source_object);
g_input_stream_clear_pending (stream);
stream->priv->closed = TRUE;
if (stream->priv->outstanding_callback)
(*stream->priv->outstanding_callback) (source_object, res, user_data);
g_object_unref (stream);
}
/**
* g_input_stream_read_async:
* @stream: A #GInputStream.
* @buffer: a buffer to read data into (which should be at least count bytes long).
* @count: the number of bytes that will be read from the stream
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): callback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Request an asynchronous read of @count bytes from the stream into the buffer
* starting at @buffer. When the operation is finished @callback will be called.
* You can then call g_input_stream_read_finish() to get the result of the
* operation.
*
* During an async request no other sync and async calls are allowed on @stream, and will
* result in %G_IO_ERROR_PENDING errors.
*
* A value of @count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, the number of bytes read into the buffer will be passed to the
* callback. It is not an error if this is not the same as the requested size, as it
* can happen e.g. near the end of a file, but generally we try to read
* as many bytes as requested. Zero is returned on end of file
* (or if @count is zero), but never otherwise.
*
* Any outstanding i/o request with higher priority (lower numerical value) will
* be executed before an outstanding request with lower priority. Default
* priority is %G_PRIORITY_DEFAULT.
*
* The asyncronous methods have a default fallback that uses threads to implement
* asynchronicity, so they are optional for inheriting classes. However, if you
* override one you must override all.
**/
void
g_input_stream_read_async (GInputStream *stream,
void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GInputStreamClass *class;
GSimpleAsyncResult *simple;
GError *error = NULL;
g_return_if_fail (G_IS_INPUT_STREAM (stream));
g_return_if_fail (buffer != NULL);
if (count == 0)
{
simple = g_simple_async_result_new (G_OBJECT (stream),
callback,
user_data,
g_input_stream_read_async);
g_simple_async_result_complete_in_idle (simple);
g_object_unref (simple);
return;
}
if (((gssize) count) < 0)
{
g_simple_async_report_error_in_idle (G_OBJECT (stream),
callback,
user_data,
G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
_("Too large count value passed to %s"),
G_STRFUNC);
return;
}
if (!g_input_stream_set_pending (stream, &error))
{
g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
error);
return;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
class->read_async (stream, buffer, count, io_priority, cancellable,
async_ready_callback_wrapper, user_data);
}
/**
* g_input_stream_read_finish:
* @stream: a #GInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes an asynchronous stream read operation.
*
* Returns: number of bytes read in, or -1 on error, or 0 on end of file.
**/
gssize
g_input_stream_read_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GInputStreamClass *class;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), -1);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
if (g_async_result_legacy_propagate_error (result, error))
return -1;
else if (g_async_result_is_tagged (result, g_input_stream_read_async))
{
/* Special case read of 0 bytes */
return 0;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
return class->read_finish (stream, result, error);
}
static void
read_bytes_callback (GObject *stream,
GAsyncResult *result,
gpointer user_data)
{
GSimpleAsyncResult *simple = user_data;
guchar *buf = g_simple_async_result_get_op_res_gpointer (simple);
GError *error = NULL;
gssize nread;
GBytes *bytes = NULL;
nread = g_input_stream_read_finish (G_INPUT_STREAM (stream),
result, &error);
if (nread == -1)
{
g_free (buf);
g_simple_async_result_take_error (simple, error);
}
else if (nread == 0)
{
g_free (buf);
bytes = g_bytes_new_static ("", 0);
}
else
bytes = g_bytes_new_take (buf, nread);
if (bytes)
{
g_simple_async_result_set_op_res_gpointer (simple, bytes,
(GDestroyNotify)g_bytes_unref);
}
g_simple_async_result_complete (simple);
g_object_unref (simple);
}
/**
* g_input_stream_read_bytes_async:
* @stream: A #GInputStream.
* @count: the number of bytes that will be read from the stream
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): callback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Request an asynchronous read of @count bytes from the stream into a
* new #GBytes. When the operation is finished @callback will be
* called. You can then call g_input_stream_read_bytes_finish() to get the
* result of the operation.
*
* During an async request no other sync and async calls are allowed
* on @stream, and will result in %G_IO_ERROR_PENDING errors.
*
* A value of @count larger than %G_MAXSSIZE will cause a
* %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, the new #GBytes will be passed to the callback. It is
* not an error if this is smaller than the requested size, as it can
* happen e.g. near the end of a file, but generally we try to read as
* many bytes as requested. Zero is returned on end of file (or if
* @count is zero), but never otherwise.
*
* Any outstanding I/O request with higher priority (lower numerical
* value) will be executed before an outstanding request with lower
* priority. Default priority is %G_PRIORITY_DEFAULT.
**/
void
g_input_stream_read_bytes_async (GInputStream *stream,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *simple;
guchar *buf;
simple = g_simple_async_result_new (G_OBJECT (stream),
callback, user_data,
g_input_stream_read_bytes_async);
buf = g_malloc (count);
g_simple_async_result_set_op_res_gpointer (simple, buf, NULL);
g_input_stream_read_async (stream, buf, count,
io_priority, cancellable,
read_bytes_callback, simple);
}
/**
* g_input_stream_read_bytes_finish:
* @stream: a #GInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes an asynchronous stream read-into-#GBytes operation.
*
* Returns: the newly-allocated #GBytes, or %NULL on error
**/
GBytes *
g_input_stream_read_bytes_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), NULL);
g_return_val_if_fail (g_simple_async_result_is_valid (result, G_OBJECT (stream), g_input_stream_read_bytes_async), NULL);
simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, error))
return NULL;
return g_bytes_ref (g_simple_async_result_get_op_res_gpointer (simple));
}
/**
* g_input_stream_skip_async:
* @stream: A #GInputStream.
* @count: the number of bytes that will be skipped from the stream
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): callback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Request an asynchronous skip of @count bytes from the stream.
* When the operation is finished @callback will be called.
* You can then call g_input_stream_skip_finish() to get the result
* of the operation.
*
* During an async request no other sync and async calls are allowed,
* and will result in %G_IO_ERROR_PENDING errors.
*
* A value of @count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
*
* On success, the number of bytes skipped will be passed to the callback.
* It is not an error if this is not the same as the requested size, as it
* can happen e.g. near the end of a file, but generally we try to skip
* as many bytes as requested. Zero is returned on end of file
* (or if @count is zero), but never otherwise.
*
* Any outstanding i/o request with higher priority (lower numerical value)
* will be executed before an outstanding request with lower priority.
* Default priority is %G_PRIORITY_DEFAULT.
*
* The asynchronous methods have a default fallback that uses threads to
* implement asynchronicity, so they are optional for inheriting classes.
* However, if you override one, you must override all.
**/
void
g_input_stream_skip_async (GInputStream *stream,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GInputStreamClass *class;
GSimpleAsyncResult *simple;
GError *error = NULL;
g_return_if_fail (G_IS_INPUT_STREAM (stream));
if (count == 0)
{
simple = g_simple_async_result_new (G_OBJECT (stream),
callback,
user_data,
g_input_stream_skip_async);
g_simple_async_result_complete_in_idle (simple);
g_object_unref (simple);
return;
}
if (((gssize) count) < 0)
{
g_simple_async_report_error_in_idle (G_OBJECT (stream),
callback,
user_data,
G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
_("Too large count value passed to %s"),
G_STRFUNC);
return;
}
if (!g_input_stream_set_pending (stream, &error))
{
g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
error);
return;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
class->skip_async (stream, count, io_priority, cancellable,
async_ready_callback_wrapper, user_data);
}
/**
* g_input_stream_skip_finish:
* @stream: a #GInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes a stream skip operation.
*
* Returns: the size of the bytes skipped, or %-1 on error.
**/
gssize
g_input_stream_skip_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GInputStreamClass *class;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), -1);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
if (g_async_result_legacy_propagate_error (result, error))
return -1;
else if (g_async_result_is_tagged (result, g_input_stream_skip_async))
{
/* Special case skip of 0 bytes */
return 0;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
return class->skip_finish (stream, result, error);
}
/**
* g_input_stream_close_async:
* @stream: A #GInputStream.
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* of the request.
* @cancellable: (allow-none): optional cancellable object
* @callback: (scope async): callback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Requests an asynchronous closes of the stream, releasing resources related to it.
* When the operation is finished @callback will be called.
* You can then call g_input_stream_close_finish() to get the result of the
* operation.
*
* For behaviour details see g_input_stream_close().
*
* The asyncronous methods have a default fallback that uses threads to implement
* asynchronicity, so they are optional for inheriting classes. However, if you
* override one you must override all.
**/
void
g_input_stream_close_async (GInputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GInputStreamClass *class;
GSimpleAsyncResult *simple;
GError *error = NULL;
g_return_if_fail (G_IS_INPUT_STREAM (stream));
if (stream->priv->closed)
{
simple = g_simple_async_result_new (G_OBJECT (stream),
callback,
user_data,
g_input_stream_close_async);
g_simple_async_result_complete_in_idle (simple);
g_object_unref (simple);
return;
}
if (!g_input_stream_set_pending (stream, &error))
{
g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
callback,
user_data,
error);
return;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
stream->priv->outstanding_callback = callback;
g_object_ref (stream);
class->close_async (stream, io_priority, cancellable,
async_ready_close_callback_wrapper, user_data);
}
/**
* g_input_stream_close_finish:
* @stream: a #GInputStream.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes closing a stream asynchronously, started from g_input_stream_close_async().
*
* Returns: %TRUE if the stream was closed successfully.
**/
gboolean
g_input_stream_close_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GInputStreamClass *class;
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
if (g_async_result_legacy_propagate_error (result, error))
return FALSE;
else if (g_async_result_is_tagged (result, g_input_stream_close_async))
{
/* Special case already closed */
return TRUE;
}
class = G_INPUT_STREAM_GET_CLASS (stream);
return class->close_finish (stream, result, error);
}
/**
* g_input_stream_is_closed:
* @stream: input stream.
*
* Checks if an input stream is closed.
*
* Returns: %TRUE if the stream is closed.
**/
gboolean
g_input_stream_is_closed (GInputStream *stream)
{
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), TRUE);
return stream->priv->closed;
}
/**
* g_input_stream_has_pending:
* @stream: input stream.
*
* Checks if an input stream has pending actions.
*
* Returns: %TRUE if @stream has pending actions.
**/
gboolean
g_input_stream_has_pending (GInputStream *stream)
{
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), TRUE);
return stream->priv->pending;
}
/**
* g_input_stream_set_pending:
* @stream: input stream
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Sets @stream to have actions pending. If the pending flag is
* already set or @stream is closed, it will return %FALSE and set
* @error.
*
* Return value: %TRUE if pending was previously unset and is now set.
**/
gboolean
g_input_stream_set_pending (GInputStream *stream, GError **error)
{
g_return_val_if_fail (G_IS_INPUT_STREAM (stream), FALSE);
if (stream->priv->closed)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
_("Stream is already closed"));
return FALSE;
}
if (stream->priv->pending)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PENDING,
/* Translators: This is an error you get if there is already an
* operation running against this stream when you try to start
* one */
_("Stream has outstanding operation"));
return FALSE;
}
stream->priv->pending = TRUE;
return TRUE;
}
/**
* g_input_stream_clear_pending:
* @stream: input stream
*
* Clears the pending flag on @stream.
**/
void
g_input_stream_clear_pending (GInputStream *stream)
{
g_return_if_fail (G_IS_INPUT_STREAM (stream));
stream->priv->pending = FALSE;
}
/********************************************
* Default implementation of async ops *
********************************************/
typedef struct {
void *buffer;
gsize count_requested;
gssize count_read;
GCancellable *cancellable;
gint io_priority;
gboolean need_idle;
} ReadData;
static void
free_read_data (ReadData *op)
{
if (op->cancellable)
g_object_unref (op->cancellable);
g_slice_free (ReadData, op);
}
static void
read_async_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
ReadData *op;
GInputStreamClass *class;
GError *error = NULL;
op = g_simple_async_result_get_op_res_gpointer (res);
class = G_INPUT_STREAM_GET_CLASS (object);
op->count_read = class->read_fn (G_INPUT_STREAM (object),
op->buffer, op->count_requested,
cancellable, &error);
if (op->count_read == -1)
g_simple_async_result_take_error (res, error);
}
static void read_async_pollable (GPollableInputStream *stream,
GSimpleAsyncResult *result);
static gboolean
read_async_pollable_ready (GPollableInputStream *stream,
gpointer user_data)
{
GSimpleAsyncResult *result = user_data;
read_async_pollable (stream, result);
return FALSE;
}
static void
read_async_pollable (GPollableInputStream *stream,
GSimpleAsyncResult *result)
{
GError *error = NULL;
ReadData *op = g_simple_async_result_get_op_res_gpointer (result);
if (g_cancellable_set_error_if_cancelled (op->cancellable, &error))
op->count_read = -1;
else
{
op->count_read = G_POLLABLE_INPUT_STREAM_GET_INTERFACE (stream)->
read_nonblocking (stream, op->buffer, op->count_requested, &error);
}
if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK))
{
GSource *source;
g_error_free (error);
op->need_idle = FALSE;
source = g_pollable_input_stream_create_source (stream, op->cancellable);
g_source_set_callback (source,
(GSourceFunc) read_async_pollable_ready,
g_object_ref (result), g_object_unref);
g_source_set_priority (source, op->io_priority);
g_source_attach (source, g_main_context_get_thread_default ());
g_source_unref (source);
return;
}
if (op->count_read == -1)
g_simple_async_result_take_error (result, error);
if (op->need_idle)
g_simple_async_result_complete_in_idle (result);
else
g_simple_async_result_complete (result);
}
static void
g_input_stream_real_read_async (GInputStream *stream,
void *buffer,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *res;
ReadData *op;
op = g_slice_new0 (ReadData);
res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data, g_input_stream_real_read_async);
g_simple_async_result_set_op_res_gpointer (res, op, (GDestroyNotify) free_read_data);
op->buffer = buffer;
op->count_requested = count;
op->cancellable = cancellable ? g_object_ref (cancellable) : NULL;
op->io_priority = io_priority;
op->need_idle = TRUE;
if (G_IS_POLLABLE_INPUT_STREAM (stream) &&
g_pollable_input_stream_can_poll (G_POLLABLE_INPUT_STREAM (stream)))
read_async_pollable (G_POLLABLE_INPUT_STREAM (stream), res);
else
g_simple_async_result_run_in_thread (res, read_async_thread, io_priority, cancellable);
g_object_unref (res);
}
static gssize
g_input_stream_real_read_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
ReadData *op;
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) ==
g_input_stream_real_read_async);
if (g_simple_async_result_propagate_error (simple, error))
return -1;
op = g_simple_async_result_get_op_res_gpointer (simple);
return op->count_read;
}
typedef struct {
gsize count_requested;
gssize count_skipped;
} SkipData;
static void
skip_async_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
SkipData *op;
GInputStreamClass *class;
GError *error = NULL;
class = G_INPUT_STREAM_GET_CLASS (object);
op = g_simple_async_result_get_op_res_gpointer (res);
op->count_skipped = class->skip (G_INPUT_STREAM (object),
op->count_requested,
cancellable, &error);
if (op->count_skipped == -1)
g_simple_async_result_take_error (res, error);
}
typedef struct {
char buffer[8192];
gsize count;
gsize count_skipped;
int io_prio;
GCancellable *cancellable;
gpointer user_data;
GAsyncReadyCallback callback;
} SkipFallbackAsyncData;
static void
skip_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GInputStreamClass *class;
SkipFallbackAsyncData *data = user_data;
SkipData *op;
GSimpleAsyncResult *simple;
GError *error = NULL;
gssize ret;
ret = g_input_stream_read_finish (G_INPUT_STREAM (source_object), res, &error);
if (ret > 0)
{
data->count -= ret;
data->count_skipped += ret;
if (data->count > 0)
{
class = G_INPUT_STREAM_GET_CLASS (source_object);
class->read_async (G_INPUT_STREAM (source_object), data->buffer, MIN (8192, data->count), data->io_prio, data->cancellable,
skip_callback_wrapper, data);
return;
}
}
op = g_new0 (SkipData, 1);
op->count_skipped = data->count_skipped;
simple = g_simple_async_result_new (source_object,
data->callback, data->user_data,
g_input_stream_real_skip_async);
g_simple_async_result_set_op_res_gpointer (simple, op, g_free);
if (ret == -1)
{
if (data->count_skipped &&
g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
/* No error, return partial read */
g_error_free (error);
else
g_simple_async_result_take_error (simple, error);
}
/* Complete immediately, not in idle, since we're already in a mainloop callout */
g_simple_async_result_complete (simple);
g_object_unref (simple);
g_free (data);
}
static void
g_input_stream_real_skip_async (GInputStream *stream,
gsize count,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GInputStreamClass *class;
SkipData *op;
SkipFallbackAsyncData *data;
GSimpleAsyncResult *res;
class = G_INPUT_STREAM_GET_CLASS (stream);
if (class->read_async == g_input_stream_real_read_async)
{
/* Read is thread-using async fallback.
* Make skip use threads too, so that we can use a possible sync skip
* implementation. */
op = g_new0 (SkipData, 1);
res = g_simple_async_result_new (G_OBJECT (stream), callback, user_data,
g_input_stream_real_skip_async);
g_simple_async_result_set_op_res_gpointer (res, op, g_free);
op->count_requested = count;
g_simple_async_result_run_in_thread (res, skip_async_thread, io_priority, cancellable);
g_object_unref (res);
}
else
{
/* TODO: Skip fallback uses too much memory, should do multiple read calls */
/* There is a custom async read function, lets use that. */
data = g_new (SkipFallbackAsyncData, 1);
data->count = count;
data->count_skipped = 0;
data->io_prio = io_priority;
data->cancellable = cancellable;
data->callback = callback;
data->user_data = user_data;
class->read_async (stream, data->buffer, MIN (8192, count), io_priority, cancellable,
skip_callback_wrapper, data);
}
}
static gssize
g_input_stream_real_skip_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
SkipData *op;
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_input_stream_real_skip_async);
if (g_simple_async_result_propagate_error (simple, error))
return -1;
op = g_simple_async_result_get_op_res_gpointer (simple);
return op->count_skipped;
}
static void
close_async_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
GInputStreamClass *class;
GError *error = NULL;
gboolean result;
/* Auto handling of cancelation disabled, and ignore
cancellation, since we want to close things anyway, although
possibly in a quick-n-dirty way. At least we never want to leak
open handles */
class = G_INPUT_STREAM_GET_CLASS (object);
if (class->close_fn)
{
result = class->close_fn (G_INPUT_STREAM (object), cancellable, &error);
if (!result)
g_simple_async_result_take_error (res, error);
}
}
static void
g_input_stream_real_close_async (GInputStream *stream,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *res;
res = g_simple_async_result_new (G_OBJECT (stream),
callback,
user_data,
g_input_stream_real_close_async);
g_simple_async_result_set_handle_cancellation (res, FALSE);
g_simple_async_result_run_in_thread (res,
close_async_thread,
io_priority,
cancellable);
g_object_unref (res);
}
static gboolean
g_input_stream_real_close_finish (GInputStream *stream,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_input_stream_real_close_async);
if (g_simple_async_result_propagate_error (simple, error))
return FALSE;
return TRUE;
}
Reference in New Issue View Git Blame Copy Permalink