/* 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/>.

 *

 * Author: Christian Kellner <gicmo@gnome.org> 

 */

#include "config.h"

#include "gmemoryinputstream.h"

#include "gpollableinputstream.h"

#include "ginputstream.h"

#include "gseekable.h"

#include "string.h"

#include "gtask.h"

#include "gioerror.h"

#include "glibintl.h"

/**

 * GMemoryInputStream:

 *

 * `GMemoryInputStream` is a class for using arbitrary

 * memory chunks as input for GIO streaming input operations.

 *

 * As of GLib 2.34, `GMemoryInputStream` implements

 * [iface@Gio.PollableInputStream].

 */

struct _GMemoryInputStreamPrivate {

  GSList *chunks;

  gsize   len;

  gsize   pos;

};

static gssize   g_memory_input_stream_read         (GInputStream         *stream,

                void                 *buffer,

                gsize                 count,

                GCancellable         *cancellable,

                GError              **error);

static gssize   g_memory_input_stream_skip         (GInputStream         *stream,

                gsize                 count,

                GCancellable         *cancellable,

                GError              **error);

static gboolean g_memory_input_stream_close        (GInputStream         *stream,

                GCancellable         *cancellable,

                GError              **error);

static void     g_memory_input_stream_skip_async   (GInputStream         *stream,

                gsize                 count,

                int                   io_priority,

                GCancellable         *cancellabl,

                GAsyncReadyCallback   callback,

                gpointer              datae);

static gssize   g_memory_input_stream_skip_finish  (GInputStream         *stream,

                GAsyncResult         *result,

                GError              **error);

static void     g_memory_input_stream_close_async  (GInputStream         *stream,

                int                   io_priority,

                GCancellable         *cancellabl,

                GAsyncReadyCallback   callback,

                gpointer              data);

static gboolean g_memory_input_stream_close_finish (GInputStream         *stream,

                GAsyncResult         *result,

                GError              **error);

static void     g_memory_input_stream_seekable_iface_init (GSeekableIface  *iface);

static goffset  g_memory_input_stream_tell                (GSeekable       *seekable);

static gboolean g_memory_input_stream_can_seek            (GSeekable       *seekable);

static gboolean g_memory_input_stream_seek                (GSeekable       *seekable,

                                                           goffset          offset,

                                                           GSeekType        type,

                                                           GCancellable    *cancellable,

                                                           GError         **error);

static gboolean g_memory_input_stream_can_truncate        (GSeekable       *seekable);

static gboolean g_memory_input_stream_truncate            (GSeekable       *seekable,

                                                           goffset          offset,

                                                           GCancellable    *cancellable,

                                                           GError         **error);

static void     g_memory_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);

static gboolean g_memory_input_stream_is_readable         (GPollableInputStream *stream);

static GSource *g_memory_input_stream_create_source       (GPollableInputStream *stream,

                 GCancellable          *cancellable);

static void     g_memory_input_stream_finalize            (GObject         *object);

G_DEFINE_TYPE_WITH_CODE (GMemoryInputStream, g_memory_input_stream, G_TYPE_INPUT_STREAM,

                         G_ADD_PRIVATE (GMemoryInputStream)

                         G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,

                                                g_memory_input_stream_seekable_iface_init);

                         G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,

                                                g_memory_input_stream_pollable_iface_init);

       )

static void

g_memory_input_stream_class_init (GMemoryInputStreamClass *klass)

{

  GObjectClass *object_class;

  GInputStreamClass *istream_class;

  object_class = G_OBJECT_CLASS (klass);

  object_class->finalize     = g_memory_input_stream_finalize;

  istream_class = G_INPUT_STREAM_CLASS (klass);

  istream_class->read_fn  = g_memory_input_stream_read;

  istream_class->skip  = g_memory_input_stream_skip;

  istream_class->close_fn = g_memory_input_stream_close;

  istream_class->skip_async  = g_memory_input_stream_skip_async;

  istream_class->skip_finish  = g_memory_input_stream_skip_finish;

  istream_class->close_async = g_memory_input_stream_close_async;

  istream_class->close_finish = g_memory_input_stream_close_finish;

}

static void

g_memory_input_stream_finalize (GObject *object)

{

  GMemoryInputStream        *stream;

  GMemoryInputStreamPrivate *priv;

  stream = G_MEMORY_INPUT_STREAM (object);

  priv = stream->priv;

  g_slist_free_full (priv->chunks, (GDestroyNotify)g_bytes_unref);

  G_OBJECT_CLASS (g_memory_input_stream_parent_class)->finalize (object);

}

static void

g_memory_input_stream_seekable_iface_init (GSeekableIface *iface)

{

  iface->tell         = g_memory_input_stream_tell;

  iface->can_seek     = g_memory_input_stream_can_seek;

  iface->seek         = g_memory_input_stream_seek;

  iface->can_truncate = g_memory_input_stream_can_truncate;

  iface->truncate_fn  = g_memory_input_stream_truncate;

}

static void

g_memory_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)

{

  iface->is_readable   = g_memory_input_stream_is_readable;

  iface->create_source = g_memory_input_stream_create_source;

}

static void

g_memory_input_stream_init (GMemoryInputStream *stream)

{

  stream->priv = g_memory_input_stream_get_instance_private (stream);

}

/**

 * g_memory_input_stream_new:

 *

 * Creates a new empty #GMemoryInputStream. 

 *

 * Returns: a new #GInputStream

 */

GInputStream *

g_memory_input_stream_new (void)

{

  GInputStream *stream;

  stream = g_object_new (G_TYPE_MEMORY_INPUT_STREAM, NULL);

  return stream;

}

/**

 * g_memory_input_stream_new_from_data:

 * @data: (array length=len) (element-type guint8) (transfer full): input data

 * @len: length of the data, may be -1 if @data is a nul-terminated string

 * @destroy: (nullable): function that is called to free @data, or %NULL

 *

 * Creates a new #GMemoryInputStream with data in memory of a given size.

 * 

 * Returns: new #GInputStream read from @data of @len bytes.

 **/

GInputStream *

g_memory_input_stream_new_from_data (const void     *data, 

                                     gssize          len,

                                     GDestroyNotify  destroy)

{

  GInputStream *stream;

  stream = g_memory_input_stream_new ();

  g_memory_input_stream_add_data (G_MEMORY_INPUT_STREAM (stream),

                                  data, len, destroy);

  return stream;

}

/**

 * g_memory_input_stream_new_from_bytes:

 * @bytes: a #GBytes

 *

 * Creates a new #GMemoryInputStream with data from the given @bytes.

 *

 * Returns: new #GInputStream read from @bytes

 *

 * Since: 2.34

 **/

GInputStream *

g_memory_input_stream_new_from_bytes (GBytes  *bytes)

{

  GInputStream *stream;

  stream = g_memory_input_stream_new ();

  g_memory_input_stream_add_bytes (G_MEMORY_INPUT_STREAM (stream),

           bytes);

  return stream;

}

/**

 * g_memory_input_stream_add_data:

 * @stream: a #GMemoryInputStream

 * @data: (array length=len) (element-type guint8) (transfer full): input data

 * @len: length of the data, may be -1 if @data is a nul-terminated string

 * @destroy: (nullable): function that is called to free @data, or %NULL

 *

 * Appends @data to data that can be read from the input stream

 */

void

g_memory_input_stream_add_data (GMemoryInputStream *stream,

                                const void         *data,

                                gssize              len,

                                GDestroyNotify      destroy)

{

  GBytes *bytes;

  if (len == -1)

    len = strlen (data);

  /* It's safe to discard the const here because we're chaining the

   * destroy callback.

   */

  bytes = g_bytes_new_with_free_func (data, len, destroy, (void*)data);

  g_memory_input_stream_add_bytes (stream, bytes);

  g_bytes_unref (bytes);

}

/**

 * g_memory_input_stream_add_bytes:

 * @stream: a #GMemoryInputStream

 * @bytes: input data

 *

 * Appends @bytes to data that can be read from the input stream.

 *

 * Since: 2.34

 */

void

g_memory_input_stream_add_bytes (GMemoryInputStream *stream,

         GBytes             *bytes)

{

  GMemoryInputStreamPrivate *priv;

  g_return_if_fail (G_IS_MEMORY_INPUT_STREAM (stream));

  g_return_if_fail (bytes != NULL);

  priv = stream->priv;

  priv->chunks = g_slist_append (priv->chunks, g_bytes_ref (bytes));

  priv->len += g_bytes_get_size (bytes);

}

static gssize

g_memory_input_stream_read (GInputStream  *stream,

                            void          *buffer,

                            gsize          count,

                            GCancellable  *cancellable,

                            GError       **error)

{

  GMemoryInputStream *memory_stream;

  GMemoryInputStreamPrivate *priv;

  GSList *l;

  GBytes *chunk;

  gsize len;

  gsize offset, start, rest, size;

  memory_stream = G_MEMORY_INPUT_STREAM (stream);

  priv = memory_stream->priv;

  count = MIN (count, priv->len - priv->pos);

  offset = 0;

  for (l = priv->chunks; l; l = l->next) 

    {

      chunk = (GBytes *)l->data;

      len = g_bytes_get_size (chunk);

      if (offset + len > priv->pos)

        break;

      offset += len;

    }

  start = priv->pos - offset;

  rest = count;

  for (; l && rest > 0; l = l->next)

    {

      const guint8* chunk_data;

      chunk = (GBytes *)l->data;

      chunk_data = g_bytes_get_data (chunk, &len);

      size = MIN (rest, len - start);

      memcpy ((guint8 *)buffer + (count - rest), chunk_data + start, size);

      rest -= size;

      start = 0;

    }

  priv->pos += count;

  return count;

}

static gssize

g_memory_input_stream_skip (GInputStream  *stream,

                            gsize          count,

                            GCancellable  *cancellable,

                            GError       **error)

{

  GMemoryInputStream *memory_stream;

  GMemoryInputStreamPrivate *priv;

  memory_stream = G_MEMORY_INPUT_STREAM (stream);

  priv = memory_stream->priv;

  count = MIN (count, priv->len - priv->pos);

  priv->pos += count;

  return count;

}

static gboolean

g_memory_input_stream_close (GInputStream  *stream,

                             GCancellable  *cancellable,

                             GError       **error)

{

  return TRUE;

}

static void

g_memory_input_stream_skip_async (GInputStream        *stream,

                                  gsize                count,

                                  int                  io_priority,

                                  GCancellable        *cancellable,

                                  GAsyncReadyCallback  callback,

                                  gpointer             user_data)

{

  GTask *task;

  gssize nskipped;

  GError *error = NULL;

  nskipped = G_INPUT_STREAM_GET_CLASS (stream)->skip (stream, count, cancellable, &error);

  task = g_task_new (stream, cancellable, callback, user_data);

  g_task_set_source_tag (task, g_memory_input_stream_skip_async);

  if (error)

    g_task_return_error (task, error);

  else

    g_task_return_int (task, nskipped);

  g_object_unref (task);

}

static gssize

g_memory_input_stream_skip_finish (GInputStream  *stream,

                                   GAsyncResult  *result,

                                   GError       **error)

{

  g_return_val_if_fail (g_task_is_valid (result, stream), -1);

  return g_task_propagate_int (G_TASK (result), error);

}

static void

g_memory_input_stream_close_async (GInputStream        *stream,

                                   int                  io_priority,

                                   GCancellable        *cancellable,

                                   GAsyncReadyCallback  callback,

                                   gpointer             user_data)

{

  GTask *task;

  task = g_task_new (stream, cancellable, callback, user_data);

  g_task_set_source_tag (task, g_memory_input_stream_close_async);

  g_task_return_boolean (task, TRUE);

  g_object_unref (task);

}

static gboolean

g_memory_input_stream_close_finish (GInputStream  *stream,

                                    GAsyncResult  *result,

                                    GError       **error)

{

  return TRUE;

}

static goffset

g_memory_input_stream_tell (GSeekable *seekable)

{

  GMemoryInputStream *memory_stream;

  GMemoryInputStreamPrivate *priv;

  memory_stream = G_MEMORY_INPUT_STREAM (seekable);

  priv = memory_stream->priv;

  return priv->pos;

}

static

gboolean g_memory_input_stream_can_seek (GSeekable *seekable)

{

  return TRUE;

}

static gboolean

g_memory_input_stream_seek (GSeekable     *seekable,

                            goffset        offset,

                            GSeekType      type,

                            GCancellable  *cancellable,

                            GError       **error)

{

  GMemoryInputStream *memory_stream;

  GMemoryInputStreamPrivate *priv;

  goffset absolute;

  memory_stream = G_MEMORY_INPUT_STREAM (seekable);

  priv = memory_stream->priv;

  switch (type) 

    {

    case G_SEEK_CUR:

      absolute = priv->pos + offset;

      break;

    case G_SEEK_SET:

      absolute = offset;

      break;

    case G_SEEK_END:

      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 || (gsize) absolute > priv->len)

    {

      g_set_error_literal (error,

                           G_IO_ERROR,

                           G_IO_ERROR_INVALID_ARGUMENT,

                           _("Invalid seek request"));

      return FALSE;

    }

  priv->pos = absolute;

  return TRUE;

}

static gboolean

g_memory_input_stream_can_truncate (GSeekable *seekable)

{

  return FALSE;

}

static gboolean

g_memory_input_stream_truncate (GSeekable     *seekable,

                                goffset        offset,

                                GCancellable  *cancellable,

                                GError       **error)

{

  g_set_error_literal (error,

                       G_IO_ERROR,

                       G_IO_ERROR_NOT_SUPPORTED,

                       _("Cannot truncate GMemoryInputStream"));

  return FALSE;

}

static gboolean

g_memory_input_stream_is_readable (GPollableInputStream *stream)

{

  return TRUE;

}

static GSource *

g_memory_input_stream_create_source (GPollableInputStream *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;

}