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18a33f72db
If we have an input parameter (or return value) we need to use (nullable). However, if it is an (inout) or (out) parameter, (optional) is sufficient. It looks like (nullable) could be used for everything according to the Annotation documentation, but (optional) is more specific.
430 lines
14 KiB
C
430 lines
14 KiB
C
/* GIO - GLib Input, Output and Streaming Library
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*
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* Copyright (C) 2006-2007 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General
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* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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* Author: Alexander Larsson <alexl@redhat.com>
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*/
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#include "config.h"
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#include <glib.h>
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#include <gfileinputstream.h>
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#include <gseekable.h>
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#include "gcancellable.h"
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#include "gasyncresult.h"
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#include "gtask.h"
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#include "gioerror.h"
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#include "glibintl.h"
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/**
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* SECTION:gfileinputstream
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* @short_description: File input streaming operations
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* @include: gio/gio.h
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* @see_also: #GInputStream, #GDataInputStream, #GSeekable
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*
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* GFileInputStream provides input streams that take their
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* content from a file.
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*
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* GFileInputStream implements #GSeekable, which allows the input
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* stream to jump to arbitrary positions in the file, provided the
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* filesystem of the file allows it. To find the position of a file
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* input stream, use g_seekable_tell(). To find out if a file input
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* stream supports seeking, use g_seekable_can_seek().
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* To position a file input stream, use g_seekable_seek().
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**/
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static void g_file_input_stream_seekable_iface_init (GSeekableIface *iface);
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static goffset g_file_input_stream_seekable_tell (GSeekable *seekable);
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static gboolean g_file_input_stream_seekable_can_seek (GSeekable *seekable);
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static gboolean g_file_input_stream_seekable_seek (GSeekable *seekable,
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goffset offset,
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GSeekType type,
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GCancellable *cancellable,
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GError **error);
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static gboolean g_file_input_stream_seekable_can_truncate (GSeekable *seekable);
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static gboolean g_file_input_stream_seekable_truncate (GSeekable *seekable,
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goffset offset,
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GCancellable *cancellable,
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GError **error);
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static void g_file_input_stream_real_query_info_async (GFileInputStream *stream,
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const char *attributes,
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int io_priority,
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GCancellable *cancellable,
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GAsyncReadyCallback callback,
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gpointer user_data);
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static GFileInfo *g_file_input_stream_real_query_info_finish (GFileInputStream *stream,
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GAsyncResult *result,
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GError **error);
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struct _GFileInputStreamPrivate {
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GAsyncReadyCallback outstanding_callback;
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};
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G_DEFINE_TYPE_WITH_CODE (GFileInputStream, g_file_input_stream, G_TYPE_INPUT_STREAM,
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G_ADD_PRIVATE (GFileInputStream)
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G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
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g_file_input_stream_seekable_iface_init))
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static void
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g_file_input_stream_class_init (GFileInputStreamClass *klass)
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{
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klass->query_info_async = g_file_input_stream_real_query_info_async;
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klass->query_info_finish = g_file_input_stream_real_query_info_finish;
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}
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static void
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g_file_input_stream_seekable_iface_init (GSeekableIface *iface)
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{
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iface->tell = g_file_input_stream_seekable_tell;
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iface->can_seek = g_file_input_stream_seekable_can_seek;
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iface->seek = g_file_input_stream_seekable_seek;
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iface->can_truncate = g_file_input_stream_seekable_can_truncate;
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iface->truncate_fn = g_file_input_stream_seekable_truncate;
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}
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static void
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g_file_input_stream_init (GFileInputStream *stream)
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{
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stream->priv = g_file_input_stream_get_instance_private (stream);
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}
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/**
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* g_file_input_stream_query_info:
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* @stream: a #GFileInputStream.
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* @attributes: a file attribute query string.
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* @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
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* @error: a #GError location to store the error occurring, or %NULL to
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* ignore.
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*
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* Queries a file input stream the given @attributes. This function blocks
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* while querying the stream. For the asynchronous (non-blocking) version
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* of this function, see g_file_input_stream_query_info_async(). While the
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* stream is blocked, the stream will set the pending flag internally, and
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* any other operations on the stream will fail with %G_IO_ERROR_PENDING.
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*
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* Returns: (transfer full): a #GFileInfo, or %NULL on error.
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**/
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GFileInfo *
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g_file_input_stream_query_info (GFileInputStream *stream,
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const char *attributes,
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GCancellable *cancellable,
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GError **error)
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{
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GFileInputStreamClass *class;
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GInputStream *input_stream;
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GFileInfo *info;
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g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
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input_stream = G_INPUT_STREAM (stream);
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if (!g_input_stream_set_pending (input_stream, error))
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return NULL;
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info = NULL;
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if (cancellable)
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g_cancellable_push_current (cancellable);
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class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
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if (class->query_info)
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info = class->query_info (stream, attributes, cancellable, error);
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else
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g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
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_("Stream doesn’t support query_info"));
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if (cancellable)
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g_cancellable_pop_current (cancellable);
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g_input_stream_clear_pending (input_stream);
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return info;
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}
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static void
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async_ready_callback_wrapper (GObject *source_object,
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GAsyncResult *res,
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gpointer user_data)
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{
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GFileInputStream *stream = G_FILE_INPUT_STREAM (source_object);
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g_input_stream_clear_pending (G_INPUT_STREAM (stream));
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if (stream->priv->outstanding_callback)
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(*stream->priv->outstanding_callback) (source_object, res, user_data);
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g_object_unref (stream);
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}
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/**
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* g_file_input_stream_query_info_async:
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* @stream: a #GFileInputStream.
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* @attributes: a file attribute query string.
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* @io_priority: the [I/O priority][io-priority] of the request
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* @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
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* @callback: (scope async): callback to call when the request is satisfied
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* @user_data: (closure): the data to pass to callback function
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*
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* Queries the stream information asynchronously.
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* When the operation is finished @callback will be called.
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* You can then call g_file_input_stream_query_info_finish()
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* to get the result of the operation.
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*
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* For the synchronous version of this function,
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* see g_file_input_stream_query_info().
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*
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* If @cancellable is not %NULL, then the operation can be cancelled by
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* triggering the cancellable object from another thread. If the operation
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* was cancelled, the error %G_IO_ERROR_CANCELLED will be set
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*
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**/
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void
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g_file_input_stream_query_info_async (GFileInputStream *stream,
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const char *attributes,
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int io_priority,
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GCancellable *cancellable,
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GAsyncReadyCallback callback,
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gpointer user_data)
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{
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GFileInputStreamClass *klass;
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GInputStream *input_stream;
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GError *error = NULL;
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g_return_if_fail (G_IS_FILE_INPUT_STREAM (stream));
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input_stream = G_INPUT_STREAM (stream);
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if (!g_input_stream_set_pending (input_stream, &error))
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{
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g_task_report_error (stream, callback, user_data,
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g_file_input_stream_query_info_async,
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error);
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return;
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}
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klass = G_FILE_INPUT_STREAM_GET_CLASS (stream);
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stream->priv->outstanding_callback = callback;
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g_object_ref (stream);
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klass->query_info_async (stream, attributes, io_priority, cancellable,
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async_ready_callback_wrapper, user_data);
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}
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/**
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* g_file_input_stream_query_info_finish:
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* @stream: a #GFileInputStream.
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* @result: a #GAsyncResult.
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* @error: a #GError location to store the error occurring,
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* or %NULL to ignore.
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*
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* Finishes an asynchronous info query operation.
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*
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* Returns: (transfer full): #GFileInfo.
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**/
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GFileInfo *
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g_file_input_stream_query_info_finish (GFileInputStream *stream,
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GAsyncResult *result,
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GError **error)
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{
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GFileInputStreamClass *class;
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g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), NULL);
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g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
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if (g_async_result_legacy_propagate_error (result, error))
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return NULL;
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else if (g_async_result_is_tagged (result, g_file_input_stream_query_info_async))
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return g_task_propagate_pointer (G_TASK (result), error);
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class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
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return class->query_info_finish (stream, result, error);
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}
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static goffset
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g_file_input_stream_tell (GFileInputStream *stream)
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{
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GFileInputStreamClass *class;
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goffset offset;
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g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), 0);
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class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
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offset = 0;
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if (class->tell)
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offset = class->tell (stream);
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return offset;
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}
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static goffset
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g_file_input_stream_seekable_tell (GSeekable *seekable)
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{
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return g_file_input_stream_tell (G_FILE_INPUT_STREAM (seekable));
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}
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static gboolean
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g_file_input_stream_can_seek (GFileInputStream *stream)
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{
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GFileInputStreamClass *class;
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gboolean can_seek;
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g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
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class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
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can_seek = FALSE;
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if (class->seek)
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{
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can_seek = TRUE;
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if (class->can_seek)
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can_seek = class->can_seek (stream);
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}
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return can_seek;
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}
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static gboolean
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g_file_input_stream_seekable_can_seek (GSeekable *seekable)
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{
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return g_file_input_stream_can_seek (G_FILE_INPUT_STREAM (seekable));
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}
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static gboolean
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g_file_input_stream_seek (GFileInputStream *stream,
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goffset offset,
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GSeekType type,
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GCancellable *cancellable,
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GError **error)
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{
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GFileInputStreamClass *class;
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GInputStream *input_stream;
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gboolean res;
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g_return_val_if_fail (G_IS_FILE_INPUT_STREAM (stream), FALSE);
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input_stream = G_INPUT_STREAM (stream);
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class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
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if (!class->seek)
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{
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g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
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_("Seek not supported on stream"));
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return FALSE;
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}
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if (!g_input_stream_set_pending (input_stream, error))
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return FALSE;
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if (cancellable)
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g_cancellable_push_current (cancellable);
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res = class->seek (stream, offset, type, cancellable, error);
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if (cancellable)
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g_cancellable_pop_current (cancellable);
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g_input_stream_clear_pending (input_stream);
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return res;
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}
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static gboolean
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g_file_input_stream_seekable_seek (GSeekable *seekable,
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goffset offset,
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GSeekType type,
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GCancellable *cancellable,
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GError **error)
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{
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return g_file_input_stream_seek (G_FILE_INPUT_STREAM (seekable),
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offset, type, cancellable, error);
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}
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static gboolean
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g_file_input_stream_seekable_can_truncate (GSeekable *seekable)
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{
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return FALSE;
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}
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static gboolean
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g_file_input_stream_seekable_truncate (GSeekable *seekable,
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goffset offset,
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GCancellable *cancellable,
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GError **error)
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{
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g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
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_("Truncate not allowed on input stream"));
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return FALSE;
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}
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/********************************************
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* Default implementation of async ops *
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********************************************/
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static void
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query_info_async_thread (GTask *task,
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gpointer source_object,
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gpointer task_data,
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GCancellable *cancellable)
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{
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GFileInputStream *stream = source_object;
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const char *attributes = task_data;
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GFileInputStreamClass *class;
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GError *error = NULL;
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GFileInfo *info = NULL;
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class = G_FILE_INPUT_STREAM_GET_CLASS (stream);
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if (class->query_info)
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info = class->query_info (stream, attributes, cancellable, &error);
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else
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g_set_error_literal (&error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
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_("Stream doesn’t support query_info"));
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if (info == NULL)
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g_task_return_error (task, error);
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else
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g_task_return_pointer (task, info, g_object_unref);
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}
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static void
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g_file_input_stream_real_query_info_async (GFileInputStream *stream,
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const char *attributes,
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int io_priority,
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GCancellable *cancellable,
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GAsyncReadyCallback callback,
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gpointer user_data)
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{
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GTask *task;
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task = g_task_new (stream, cancellable, callback, user_data);
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g_task_set_source_tag (task, g_file_input_stream_real_query_info_async);
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g_task_set_task_data (task, g_strdup (attributes), g_free);
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g_task_set_priority (task, io_priority);
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g_task_run_in_thread (task, query_info_async_thread);
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g_object_unref (task);
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}
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static GFileInfo *
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g_file_input_stream_real_query_info_finish (GFileInputStream *stream,
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GAsyncResult *res,
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GError **error)
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{
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g_return_val_if_fail (g_task_is_valid (res, stream), NULL);
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return g_task_propagate_pointer (G_TASK (res), error);
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}
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