| /* GIO - GLib Input, Output and Streaming Library |
| * |
| * Copyright (C) 2006-2007 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/>. |
| * |
| * Authors: |
| * Christian Kellner <gicmo@gnome.org> |
| * Krzysztof KosiĆski <tweenk.pl@gmail.com> |
| */ |
| |
| #include "config.h" |
| #include "gmemoryoutputstream.h" |
| #include "goutputstream.h" |
| #include "gpollableoutputstream.h" |
| #include "gseekable.h" |
| #include "gtask.h" |
| #include "gioerror.h" |
| #include "string.h" |
| #include "glibintl.h" |
| #include "gutilsprivate.h" |
| |
| |
| /** |
| * GMemoryOutputStream: |
| * |
| * `GMemoryOutputStream` is a class for using arbitrary |
| * memory chunks as output for GIO streaming output operations. |
| * |
| * As of GLib 2.34, `GMemoryOutputStream` trivially implements |
| * [iface@Gio.PollableOutputStream]: it always polls as ready. |
| */ |
| |
| #define MIN_ARRAY_SIZE 16 |
| |
| enum { |
| PROP_0, |
| PROP_DATA, |
| PROP_SIZE, |
| PROP_DATA_SIZE, |
| PROP_REALLOC_FUNCTION, |
| PROP_DESTROY_FUNCTION |
| }; |
| |
| struct _GMemoryOutputStreamPrivate |
| { |
| gpointer data; /* Write buffer */ |
| gsize len; /* Current length of the data buffer. Can change with resizing. */ |
| gsize valid_len; /* The part of data that has been written to */ |
| gsize pos; /* Current position in the stream. Distinct from valid_len, |
| because the stream is seekable. */ |
| |
| GReallocFunc realloc_fn; |
| GDestroyNotify destroy; |
| }; |
| |
| static void g_memory_output_stream_set_property (GObject *object, |
| guint prop_id, |
| const GValue *value, |
| GParamSpec *pspec); |
| static void g_memory_output_stream_get_property (GObject *object, |
| guint prop_id, |
| GValue *value, |
| GParamSpec *pspec); |
| static void g_memory_output_stream_finalize (GObject *object); |
| |
| static gssize g_memory_output_stream_write (GOutputStream *stream, |
| const void *buffer, |
| gsize count, |
| GCancellable *cancellable, |
| GError **error); |
| |
| static gboolean g_memory_output_stream_close (GOutputStream *stream, |
| GCancellable *cancellable, |
| GError **error); |
| |
| static void g_memory_output_stream_close_async (GOutputStream *stream, |
| int io_priority, |
| GCancellable *cancellable, |
| GAsyncReadyCallback callback, |
| gpointer data); |
| static gboolean g_memory_output_stream_close_finish (GOutputStream *stream, |
| GAsyncResult *result, |
| GError **error); |
| |
| static void g_memory_output_stream_seekable_iface_init (GSeekableIface *iface); |
| static goffset g_memory_output_stream_tell (GSeekable *seekable); |
| static gboolean g_memory_output_stream_can_seek (GSeekable *seekable); |
| static gboolean g_memory_output_stream_seek (GSeekable *seekable, |
| goffset offset, |
| GSeekType type, |
| GCancellable *cancellable, |
| GError **error); |
| static gboolean g_memory_output_stream_can_truncate (GSeekable *seekable); |
| static gboolean g_memory_output_stream_truncate (GSeekable *seekable, |
| goffset offset, |
| GCancellable *cancellable, |
| GError **error); |
| |
| static gboolean g_memory_output_stream_is_writable (GPollableOutputStream *stream); |
| static GSource *g_memory_output_stream_create_source (GPollableOutputStream *stream, |
| GCancellable *cancellable); |
| |
| static void g_memory_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface); |
| |
| G_DEFINE_TYPE_WITH_CODE (GMemoryOutputStream, g_memory_output_stream, G_TYPE_OUTPUT_STREAM, |
| G_ADD_PRIVATE (GMemoryOutputStream) |
| G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE, |
| g_memory_output_stream_seekable_iface_init); |
| G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM, |
| g_memory_output_stream_pollable_iface_init)) |
| |
| |
| static void |
| g_memory_output_stream_class_init (GMemoryOutputStreamClass *klass) |
| { |
| GOutputStreamClass *ostream_class; |
| GObjectClass *gobject_class; |
| |
| gobject_class = G_OBJECT_CLASS (klass); |
| gobject_class->set_property = g_memory_output_stream_set_property; |
| gobject_class->get_property = g_memory_output_stream_get_property; |
| gobject_class->finalize = g_memory_output_stream_finalize; |
| |
| ostream_class = G_OUTPUT_STREAM_CLASS (klass); |
| |
| ostream_class->write_fn = g_memory_output_stream_write; |
| ostream_class->close_fn = g_memory_output_stream_close; |
| ostream_class->close_async = g_memory_output_stream_close_async; |
| ostream_class->close_finish = g_memory_output_stream_close_finish; |
| |
| /** |
| * GMemoryOutputStream:data: |
| * |
| * Pointer to buffer where data will be written. |
| * |
| * Since: 2.24 |
| **/ |
| g_object_class_install_property (gobject_class, |
| PROP_DATA, |
| g_param_spec_pointer ("data", NULL, NULL, |
| G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | |
| G_PARAM_STATIC_STRINGS)); |
| |
| /** |
| * GMemoryOutputStream:size: |
| * |
| * Current size of the data buffer. |
| * |
| * Since: 2.24 |
| **/ |
| g_object_class_install_property (gobject_class, |
| PROP_SIZE, |
| g_param_spec_ulong ("size", NULL, NULL, |
| 0, G_MAXULONG, 0, |
| G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | |
| G_PARAM_STATIC_STRINGS)); |
| |
| /** |
| * GMemoryOutputStream:data-size: |
| * |
| * Size of data written to the buffer. |
| * |
| * Since: 2.24 |
| **/ |
| g_object_class_install_property (gobject_class, |
| PROP_DATA_SIZE, |
| g_param_spec_ulong ("data-size", NULL, NULL, |
| 0, G_MAXULONG, 0, |
| G_PARAM_READABLE | |
| G_PARAM_STATIC_STRINGS)); |
| |
| /** |
| * GMemoryOutputStream:realloc-function: (skip) |
| * |
| * Function with realloc semantics called to enlarge the buffer. |
| * |
| * Since: 2.24 |
| **/ |
| g_object_class_install_property (gobject_class, |
| PROP_REALLOC_FUNCTION, |
| g_param_spec_pointer ("realloc-function", NULL, NULL, |
| G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | |
| G_PARAM_STATIC_STRINGS)); |
| |
| /** |
| * GMemoryOutputStream:destroy-function: (skip) |
| * |
| * Function called with the buffer as argument when the stream is destroyed. |
| * |
| * Since: 2.24 |
| **/ |
| g_object_class_install_property (gobject_class, |
| PROP_DESTROY_FUNCTION, |
| g_param_spec_pointer ("destroy-function", NULL, NULL, |
| G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | |
| G_PARAM_STATIC_STRINGS)); |
| } |
| |
| static void |
| g_memory_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface) |
| { |
| iface->is_writable = g_memory_output_stream_is_writable; |
| iface->create_source = g_memory_output_stream_create_source; |
| } |
| |
| static void |
| g_memory_output_stream_set_property (GObject *object, |
| guint prop_id, |
| const GValue *value, |
| GParamSpec *pspec) |
| { |
| GMemoryOutputStream *stream; |
| GMemoryOutputStreamPrivate *priv; |
| |
| stream = G_MEMORY_OUTPUT_STREAM (object); |
| priv = stream->priv; |
| |
| switch (prop_id) |
| { |
| case PROP_DATA: |
| priv->data = g_value_get_pointer (value); |
| break; |
| case PROP_SIZE: |
| priv->len = g_value_get_ulong (value); |
| break; |
| case PROP_REALLOC_FUNCTION: |
| priv->realloc_fn = g_value_get_pointer (value); |
| break; |
| case PROP_DESTROY_FUNCTION: |
| priv->destroy = g_value_get_pointer (value); |
| break; |
| default: |
| G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); |
| break; |
| } |
| } |
| |
| static void |
| g_memory_output_stream_get_property (GObject *object, |
| guint prop_id, |
| GValue *value, |
| GParamSpec *pspec) |
| { |
| GMemoryOutputStream *stream; |
| GMemoryOutputStreamPrivate *priv; |
| |
| stream = G_MEMORY_OUTPUT_STREAM (object); |
| priv = stream->priv; |
| |
| switch (prop_id) |
| { |
| case PROP_DATA: |
| g_value_set_pointer (value, priv->data); |
| break; |
| case PROP_SIZE: |
| g_value_set_ulong (value, priv->len); |
| break; |
| case PROP_DATA_SIZE: |
| g_value_set_ulong (value, priv->valid_len); |
| break; |
| case PROP_REALLOC_FUNCTION: |
| g_value_set_pointer (value, priv->realloc_fn); |
| break; |
| case PROP_DESTROY_FUNCTION: |
| g_value_set_pointer (value, priv->destroy); |
| break; |
| default: |
| G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); |
| break; |
| } |
| } |
| |
| static void |
| g_memory_output_stream_finalize (GObject *object) |
| { |
| GMemoryOutputStream *stream; |
| GMemoryOutputStreamPrivate *priv; |
| |
| stream = G_MEMORY_OUTPUT_STREAM (object); |
| priv = stream->priv; |
| |
| if (priv->destroy) |
| priv->destroy (priv->data); |
| |
| G_OBJECT_CLASS (g_memory_output_stream_parent_class)->finalize (object); |
| } |
| |
| static void |
| g_memory_output_stream_seekable_iface_init (GSeekableIface *iface) |
| { |
| iface->tell = g_memory_output_stream_tell; |
| iface->can_seek = g_memory_output_stream_can_seek; |
| iface->seek = g_memory_output_stream_seek; |
| iface->can_truncate = g_memory_output_stream_can_truncate; |
| iface->truncate_fn = g_memory_output_stream_truncate; |
| } |
| |
| |
| static void |
| g_memory_output_stream_init (GMemoryOutputStream *stream) |
| { |
| stream->priv = g_memory_output_stream_get_instance_private (stream); |
| stream->priv->pos = 0; |
| stream->priv->valid_len = 0; |
| } |
| |
| /** |
| * g_memory_output_stream_new: (skip) |
| * @data: (nullable): pointer to a chunk of memory to use, or %NULL |
| * @size: the size of @data |
| * @realloc_function: (nullable): a function with realloc() semantics (like g_realloc()) |
| * to be called when @data needs to be grown, or %NULL |
| * @destroy_function: (nullable): a function to be called on @data when the stream is |
| * finalized, or %NULL |
| * |
| * Creates a new #GMemoryOutputStream. |
| * |
| * In most cases this is not the function you want. See |
| * g_memory_output_stream_new_resizable() instead. |
| * |
| * If @data is non-%NULL, the stream will use that for its internal storage. |
| * |
| * If @realloc_fn is non-%NULL, it will be used for resizing the internal |
| * storage when necessary and the stream will be considered resizable. |
| * In that case, the stream will start out being (conceptually) empty. |
| * @size is used only as a hint for how big @data is. Specifically, |
| * seeking to the end of a newly-created stream will seek to zero, not |
| * @size. Seeking past the end of the stream and then writing will |
| * introduce a zero-filled gap. |
| * |
| * If @realloc_fn is %NULL then the stream is fixed-sized. Seeking to |
| * the end will seek to @size exactly. Writing past the end will give |
| * an 'out of space' error. Attempting to seek past the end will fail. |
| * Unlike the resizable case, seeking to an offset within the stream and |
| * writing will preserve the bytes passed in as @data before that point |
| * and will return them as part of g_memory_output_stream_steal_data(). |
| * If you intend to seek you should probably therefore ensure that @data |
| * is properly initialised. |
| * |
| * It is probably only meaningful to provide @data and @size in the case |
| * that you want a fixed-sized stream. Put another way: if @realloc_fn |
| * is non-%NULL then it makes most sense to give @data as %NULL and |
| * @size as 0 (allowing #GMemoryOutputStream to do the initial |
| * allocation for itself). |
| * |
| * |[<!-- language="C" --> |
| * // a stream that can grow |
| * stream = g_memory_output_stream_new (NULL, 0, realloc, free); |
| * |
| * // another stream that can grow |
| * stream2 = g_memory_output_stream_new (NULL, 0, g_realloc, g_free); |
| * |
| * // a fixed-size stream |
| * data = malloc (200); |
| * stream3 = g_memory_output_stream_new (data, 200, NULL, free); |
| * ]| |
| * |
| * Returns: A newly created #GMemoryOutputStream object. |
| **/ |
| GOutputStream * |
| g_memory_output_stream_new (gpointer data, |
| gsize size, |
| GReallocFunc realloc_function, |
| GDestroyNotify destroy_function) |
| { |
| GOutputStream *stream; |
| |
| stream = g_object_new (G_TYPE_MEMORY_OUTPUT_STREAM, |
| "data", data, |
| "size", size, |
| "realloc-function", realloc_function, |
| "destroy-function", destroy_function, |
| NULL); |
| |
| return stream; |
| } |
| |
| /** |
| * g_memory_output_stream_new_resizable: |
| * |
| * Creates a new #GMemoryOutputStream, using g_realloc() and g_free() |
| * for memory allocation. |
| * |
| * Since: 2.36 |
| */ |
| GOutputStream * |
| g_memory_output_stream_new_resizable (void) |
| { |
| return g_memory_output_stream_new (NULL, 0, g_realloc, g_free); |
| } |
| |
| /** |
| * g_memory_output_stream_get_data: |
| * @ostream: a #GMemoryOutputStream |
| * |
| * Gets any loaded data from the @ostream. |
| * |
| * Note that the returned pointer may become invalid on the next |
| * write or truncate operation on the stream. |
| * |
| * Returns: (transfer none): pointer to the stream's data, or %NULL if the data |
| * has been stolen |
| **/ |
| gpointer |
| g_memory_output_stream_get_data (GMemoryOutputStream *ostream) |
| { |
| g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), NULL); |
| |
| return ostream->priv->data; |
| } |
| |
| /** |
| * g_memory_output_stream_get_size: |
| * @ostream: a #GMemoryOutputStream |
| * |
| * Gets the size of the currently allocated data area (available from |
| * g_memory_output_stream_get_data()). |
| * |
| * You probably don't want to use this function on resizable streams. |
| * See g_memory_output_stream_get_data_size() instead. For resizable |
| * streams the size returned by this function is an implementation |
| * detail and may be change at any time in response to operations on the |
| * stream. |
| * |
| * If the stream is fixed-sized (ie: no realloc was passed to |
| * g_memory_output_stream_new()) then this is the maximum size of the |
| * stream and further writes will return %G_IO_ERROR_NO_SPACE. |
| * |
| * In any case, if you want the number of bytes currently written to the |
| * stream, use g_memory_output_stream_get_data_size(). |
| * |
| * Returns: the number of bytes allocated for the data buffer |
| */ |
| gsize |
| g_memory_output_stream_get_size (GMemoryOutputStream *ostream) |
| { |
| g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), 0); |
| |
| return ostream->priv->len; |
| } |
| |
| /** |
| * g_memory_output_stream_get_data_size: |
| * @ostream: a #GMemoryOutputStream |
| * |
| * Returns the number of bytes from the start up to including the last |
| * byte written in the stream that has not been truncated away. |
| * |
| * Returns: the number of bytes written to the stream |
| * |
| * Since: 2.18 |
| */ |
| gsize |
| g_memory_output_stream_get_data_size (GMemoryOutputStream *ostream) |
| { |
| g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), 0); |
| |
| return ostream->priv->valid_len; |
| } |
| |
| /** |
| * g_memory_output_stream_steal_data: |
| * @ostream: a #GMemoryOutputStream |
| * |
| * Gets any loaded data from the @ostream. Ownership of the data |
| * is transferred to the caller; when no longer needed it must be |
| * freed using the free function set in @ostream's |
| * #GMemoryOutputStream:destroy-function property. |
| * |
| * @ostream must be closed before calling this function. |
| * |
| * Returns: (transfer full): the stream's data, or %NULL if it has previously |
| * been stolen |
| * |
| * Since: 2.26 |
| **/ |
| gpointer |
| g_memory_output_stream_steal_data (GMemoryOutputStream *ostream) |
| { |
| gpointer data; |
| |
| g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), NULL); |
| g_return_val_if_fail (g_output_stream_is_closed (G_OUTPUT_STREAM (ostream)), NULL); |
| |
| data = ostream->priv->data; |
| ostream->priv->data = NULL; |
| |
| return data; |
| } |
| |
| /** |
| * g_memory_output_stream_steal_as_bytes: |
| * @ostream: a #GMemoryOutputStream |
| * |
| * Returns data from the @ostream as a #GBytes. @ostream must be |
| * closed before calling this function. |
| * |
| * Returns: (transfer full): the stream's data |
| * |
| * Since: 2.34 |
| **/ |
| GBytes * |
| g_memory_output_stream_steal_as_bytes (GMemoryOutputStream *ostream) |
| { |
| GBytes *result; |
| |
| g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), NULL); |
| g_return_val_if_fail (g_output_stream_is_closed (G_OUTPUT_STREAM (ostream)), NULL); |
| |
| result = g_bytes_new_with_free_func (ostream->priv->data, |
| ostream->priv->valid_len, |
| ostream->priv->destroy, |
| ostream->priv->data); |
| ostream->priv->data = NULL; |
| |
| return result; |
| } |
| |
| static gboolean |
| array_resize (GMemoryOutputStream *ostream, |
| gsize size, |
| gboolean allow_partial, |
| GError **error) |
| { |
| GMemoryOutputStreamPrivate *priv; |
| gpointer data; |
| gsize len; |
| |
| priv = ostream->priv; |
| |
| if (priv->len == size) |
| return TRUE; |
| |
| if (!priv->realloc_fn) |
| { |
| if (allow_partial && |
| priv->pos < priv->len) |
| return TRUE; /* Short write */ |
| |
| g_set_error_literal (error, |
| G_IO_ERROR, |
| G_IO_ERROR_NO_SPACE, |
| _("Memory output stream not resizable")); |
| return FALSE; |
| } |
| |
| len = priv->len; |
| data = priv->realloc_fn (priv->data, size); |
| |
| if (size > 0 && !data) |
| { |
| if (allow_partial && |
| priv->pos < priv->len) |
| return TRUE; /* Short write */ |
| |
| g_set_error_literal (error, |
| G_IO_ERROR, |
| G_IO_ERROR_NO_SPACE, |
| _("Failed to resize memory output stream")); |
| return FALSE; |
| } |
| |
| if (size > len) |
| memset ((guint8 *)data + len, 0, size - len); |
| |
| priv->data = data; |
| priv->len = size; |
| |
| if (priv->len < priv->valid_len) |
| priv->valid_len = priv->len; |
| |
| return TRUE; |
| } |
| |
| static gssize |
| g_memory_output_stream_write (GOutputStream *stream, |
| const void *buffer, |
| gsize count, |
| GCancellable *cancellable, |
| GError **error) |
| { |
| GMemoryOutputStream *ostream; |
| GMemoryOutputStreamPrivate *priv; |
| guint8 *dest; |
| gsize new_size; |
| |
| ostream = G_MEMORY_OUTPUT_STREAM (stream); |
| priv = ostream->priv; |
| |
| if (count == 0) |
| return 0; |
| |
| /* Check for address space overflow, but only if the buffer is resizable. |
| Otherwise we just do a short write and don't worry. */ |
| if (priv->realloc_fn && priv->pos + count < priv->pos) |
| goto overflow; |
| |
| if (priv->pos + count > priv->len) |
| { |
| /* At least enough to fit the write, rounded up for greater than |
| * linear growth. |
| * |
| * Assuming that we're using something like realloc(), the kernel |
| * will overcommit memory to us, so doubling the size each time |
| * will keep the number of realloc calls low without wasting too |
| * much memory. |
| */ |
| new_size = g_nearest_pow (priv->pos + count); |
| /* Check for overflow again. We have checked if |
| pos + count > G_MAXSIZE, but now check if g_nearest_pow () has |
| overflowed */ |
| if (new_size == 0) |
| goto overflow; |
| |
| new_size = MAX (new_size, MIN_ARRAY_SIZE); |
| if (!array_resize (ostream, new_size, TRUE, error)) |
| return -1; |
| } |
| |
| /* Make sure we handle short writes if the array_resize |
| only added part of the required memory */ |
| count = MIN (count, priv->len - priv->pos); |
| |
| dest = (guint8 *)priv->data + priv->pos; |
| memcpy (dest, buffer, count); |
| priv->pos += count; |
| |
| if (priv->pos > priv->valid_len) |
| priv->valid_len = priv->pos; |
| |
| return count; |
| |
| overflow: |
| /* Overflow: buffer size would need to be bigger than G_MAXSIZE. */ |
| g_set_error_literal (error, |
| G_IO_ERROR, |
| G_IO_ERROR_NO_SPACE, |
| _("Amount of memory required to process the write is " |
| "larger than available address space")); |
| return -1; |
| } |
| |
| static gboolean |
| g_memory_output_stream_close (GOutputStream *stream, |
| GCancellable *cancellable, |
| GError **error) |
| { |
| return TRUE; |
| } |
| |
| static void |
| g_memory_output_stream_close_async (GOutputStream *stream, |
| int io_priority, |
| GCancellable *cancellable, |
| GAsyncReadyCallback callback, |
| gpointer data) |
| { |
| GTask *task; |
| |
| task = g_task_new (stream, cancellable, callback, data); |
| g_task_set_source_tag (task, g_memory_output_stream_close_async); |
| |
| /* will always return TRUE */ |
| g_memory_output_stream_close (stream, cancellable, NULL); |
| |
| g_task_return_boolean (task, TRUE); |
| g_object_unref (task); |
| } |
| |
| static gboolean |
| g_memory_output_stream_close_finish (GOutputStream *stream, |
| GAsyncResult *result, |
| GError **error) |
| { |
| g_return_val_if_fail (g_task_is_valid (result, stream), FALSE); |
| |
| return g_task_propagate_boolean (G_TASK (result), error); |
| } |
| |
| static goffset |
| g_memory_output_stream_tell (GSeekable *seekable) |
| { |
| GMemoryOutputStream *stream; |
| GMemoryOutputStreamPrivate *priv; |
| |
| stream = G_MEMORY_OUTPUT_STREAM (seekable); |
| priv = stream->priv; |
| |
| return priv->pos; |
| } |
| |
| static gboolean |
| g_memory_output_stream_can_seek (GSeekable *seekable) |
| { |
| return TRUE; |
| } |
| |
| static gboolean |
| g_memory_output_stream_seek (GSeekable *seekable, |
| goffset offset, |
| GSeekType type, |
| GCancellable *cancellable, |
| GError **error) |
| { |
| GMemoryOutputStream *stream; |
| GMemoryOutputStreamPrivate *priv; |
| goffset absolute; |
| |
| stream = G_MEMORY_OUTPUT_STREAM (seekable); |
| priv = stream->priv; |
| |
| switch (type) |
| { |
| case G_SEEK_CUR: |
| absolute = priv->pos + offset; |
| break; |
| |
| case G_SEEK_SET: |
| absolute = offset; |
| break; |
| |
| case G_SEEK_END: |
| /* For resizable streams, we consider the end to be the data |
| * length. For fixed-sized streams, we consider the end to be the |
| * size of the buffer. |
| */ |
| if (priv->realloc_fn) |
| absolute = priv->valid_len + offset; |
| else |
| absolute = priv->len + offset; |
| break; |
| |
| default: |
| g_set_error_literal (error, |
| G_IO_ERROR, |
| G_IO_ERROR_INVALID_ARGUMENT, |
| _("Invalid GSeekType supplied")); |
| |
| return FALSE; |
| } |
| |
| if (absolute < 0) |
| { |
| g_set_error_literal (error, |
| G_IO_ERROR, |
| G_IO_ERROR_INVALID_ARGUMENT, |
| _("Requested seek before the beginning of the stream")); |
| return FALSE; |
| } |
| |
| /* Can't seek past the end of a fixed-size stream. |
| * |
| * Note: seeking to the non-existent byte at the end of a fixed-sized |
| * stream is valid (eg: a 1-byte fixed sized stream can have position |
| * 0 or 1). Therefore '>' is what we want. |
| * */ |
| if (priv->realloc_fn == NULL && (gsize) absolute > priv->len) |
| { |
| g_set_error_literal (error, |
| G_IO_ERROR, |
| G_IO_ERROR_INVALID_ARGUMENT, |
| _("Requested seek beyond the end of the stream")); |
| return FALSE; |
| } |
| |
| priv->pos = absolute; |
| |
| return TRUE; |
| } |
| |
| static gboolean |
| g_memory_output_stream_can_truncate (GSeekable *seekable) |
| { |
| GMemoryOutputStream *ostream; |
| GMemoryOutputStreamPrivate *priv; |
| |
| ostream = G_MEMORY_OUTPUT_STREAM (seekable); |
| priv = ostream->priv; |
| |
| /* We do not allow truncation of fixed-sized streams */ |
| return priv->realloc_fn != NULL; |
| } |
| |
| static gboolean |
| g_memory_output_stream_truncate (GSeekable *seekable, |
| goffset offset, |
| GCancellable *cancellable, |
| GError **error) |
| { |
| GMemoryOutputStream *ostream = G_MEMORY_OUTPUT_STREAM (seekable); |
| |
| if (!array_resize (ostream, offset, FALSE, error)) |
| return FALSE; |
| |
| ostream->priv->valid_len = offset; |
| |
| return TRUE; |
| } |
| |
| static gboolean |
| g_memory_output_stream_is_writable (GPollableOutputStream *stream) |
| { |
| return TRUE; |
| } |
| |
| static GSource * |
| g_memory_output_stream_create_source (GPollableOutputStream *stream, |
| GCancellable *cancellable) |
| { |
| GSource *base_source, *pollable_source; |
| |
| base_source = g_timeout_source_new (0); |
| pollable_source = g_pollable_source_new_full (stream, base_source, cancellable); |
| g_source_unref (base_source); |
| |
| return pollable_source; |
| } |