gio/gmemoryinputstream.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: Christian Kellner <gicmo@gnome.org>
  21  */
  22
  23 #include "config.h"
  24 #include "gmemoryinputstream.h"
  25 #include "ginputstream.h"
  26 #include "gseekable.h"
  27 #include "string.h"
  28 #include "gsimpleasyncresult.h"
  29 #include "gioerror.h"
  30 #include "glibintl.h"
  31
  32
  33 /**
  34  * SECTION:gmemoryinputstream
  35  * @short_description: Streaming input operations on memory chunks
  36  * @include: gio/gio.h
  37  * @see_also: #GMemoryOutputStream
  38  *
  39  * #GMemoryInputStream is a class for using arbitrary
  40  * memory chunks as input for GIO streaming input operations.
  41  *
  42  */
  43
  44 typedef struct _Chunk Chunk;
  45
  46 struct _Chunk {
  47   guint8         *data;
  48   gsize           len;
  49   GDestroyNotify  destroy;
  50 };
  51
  52 struct _GMemoryInputStreamPrivate {
  53   GSList *chunks;
  54   gsize   len;
  55   gsize   pos;
  56 };
  57
  58 static gssize   g_memory_input_stream_read         (GInputStream         *stream,
  59                                                     void                 *buffer,
  60                                                     gsize                 count,
  61                                                     GCancellable         *cancellable,
  62                                                     GError              **error);
  63 static gssize   g_memory_input_stream_skip         (GInputStream         *stream,
  64                                                     gsize                 count,
  65                                                     GCancellable         *cancellable,
  66                                                     GError              **error);
  67 static gboolean g_memory_input_stream_close        (GInputStream         *stream,
  68                                                     GCancellable         *cancellable,
  69                                                     GError              **error);
  70 static void     g_memory_input_stream_read_async   (GInputStream         *stream,
  71                                                     void                 *buffer,
  72                                                     gsize                 count,
  73                                                     int                   io_priority,
  74                                                     GCancellable         *cancellable,
  75                                                     GAsyncReadyCallback   callback,
  76                                                     gpointer              user_data);
  77 static gssize   g_memory_input_stream_read_finish  (GInputStream         *stream,
  78                                                     GAsyncResult         *result,
  79                                                     GError              **error);
  80 static void     g_memory_input_stream_skip_async   (GInputStream         *stream,
  81                                                     gsize                 count,
  82                                                     int                   io_priority,
  83                                                     GCancellable         *cancellabl,
  84                                                     GAsyncReadyCallback   callback,
  85                                                     gpointer              datae);
  86 static gssize   g_memory_input_stream_skip_finish  (GInputStream         *stream,
  87                                                     GAsyncResult         *result,
  88                                                     GError              **error);
  89 static void     g_memory_input_stream_close_async  (GInputStream         *stream,
  90                                                     int                   io_priority,
  91                                                     GCancellable         *cancellabl,
  92                                                     GAsyncReadyCallback   callback,
  93                                                     gpointer              data);
  94 static gboolean g_memory_input_stream_close_finish (GInputStream         *stream,
  95                                                     GAsyncResult         *result,
  96                                                     GError              **error);
  97
  98 static void     g_memory_input_stream_seekable_iface_init (GSeekableIface  *iface);
  99 static goffset  g_memory_input_stream_tell                (GSeekable       *seekable);
 100 static gboolean g_memory_input_stream_can_seek            (GSeekable       *seekable);
 101 static gboolean g_memory_input_stream_seek                (GSeekable       *seekable,
 102                                                            goffset          offset,
 103                                                            GSeekType        type,
 104                                                            GCancellable    *cancellable,
 105                                                            GError         **error);
 106 static gboolean g_memory_input_stream_can_truncate        (GSeekable       *seekable);
 107 static gboolean g_memory_input_stream_truncate            (GSeekable       *seekable,
 108                                                            goffset          offset,
 109                                                            GCancellable    *cancellable,
 110                                                            GError         **error);
 111 static void     g_memory_input_stream_finalize            (GObject         *object);
 112
 113 G_DEFINE_TYPE_WITH_CODE (GMemoryInputStream, g_memory_input_stream, G_TYPE_INPUT_STREAM,
 114                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
 115                                                 g_memory_input_stream_seekable_iface_init))
 116
 117
 118 static void
 119 g_memory_input_stream_class_init (GMemoryInputStreamClass *klass)
 120 {
 121   GObjectClass *object_class;
 122   GInputStreamClass *istream_class;
 123
 124   g_type_class_add_private (klass, sizeof (GMemoryInputStreamPrivate));
 125
 126   object_class = G_OBJECT_CLASS (klass);
 127   object_class->finalize     = g_memory_input_stream_finalize;
 128
 129   istream_class = G_INPUT_STREAM_CLASS (klass);
 130   istream_class->read_fn  = g_memory_input_stream_read;
 131   istream_class->skip  = g_memory_input_stream_skip;
 132   istream_class->close_fn = g_memory_input_stream_close;
 133
 134   istream_class->read_async  = g_memory_input_stream_read_async;
 135   istream_class->read_finish  = g_memory_input_stream_read_finish;
 136   istream_class->skip_async  = g_memory_input_stream_skip_async;
 137   istream_class->skip_finish  = g_memory_input_stream_skip_finish;
 138   istream_class->close_async = g_memory_input_stream_close_async;
 139   istream_class->close_finish = g_memory_input_stream_close_finish;
 140 }
 141
 142 static void
 143 free_chunk (gpointer data,
 144             gpointer user_data)
 145 {
 146   Chunk *chunk = data;
 147
 148   if (chunk->destroy)
 149     chunk->destroy (chunk->data);
 150
 151   g_slice_free (Chunk, chunk);
 152 }
 153
 154 static void
 155 g_memory_input_stream_finalize (GObject *object)
 156 {
 157   GMemoryInputStream        *stream;
 158   GMemoryInputStreamPrivate *priv;
 159
 160   stream = G_MEMORY_INPUT_STREAM (object);
 161   priv = stream->priv;
 162
 163   g_slist_foreach (priv->chunks, free_chunk, NULL);
 164   g_slist_free (priv->chunks);
 165
 166   G_OBJECT_CLASS (g_memory_input_stream_parent_class)->finalize (object);
 167 }
 168
 169 static void
 170 g_memory_input_stream_seekable_iface_init (GSeekableIface *iface)
 171 {
 172   iface->tell         = g_memory_input_stream_tell;
 173   iface->can_seek     = g_memory_input_stream_can_seek;
 174   iface->seek         = g_memory_input_stream_seek;
 175   iface->can_truncate = g_memory_input_stream_can_truncate;
 176   iface->truncate_fn  = g_memory_input_stream_truncate;
 177 }
 178
 179 static void
 180 g_memory_input_stream_init (GMemoryInputStream *stream)
 181 {
 182   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 183                                               G_TYPE_MEMORY_INPUT_STREAM,
 184                                               GMemoryInputStreamPrivate);
 185 }
 186
 187 /**
 188  * g_memory_input_stream_new:
 189  *
 190  * Creates a new empty #GMemoryInputStream.
 191  *
 192  * Returns: a new #GInputStream
 193  */
 194 GInputStream *
 195 g_memory_input_stream_new (void)
 196 {
 197   GInputStream *stream;
 198
 199   stream = g_object_new (G_TYPE_MEMORY_INPUT_STREAM, NULL);
 200
 201   return stream;
 202 }
 203
 204 /**
 205  * g_memory_input_stream_new_from_data:
 206  * @data: (array length=len) (element-type guint8): input data
 207  * @len: length of the data, may be -1 if @data is a nul-terminated string
 208  * @destroy: (allow-none): function that is called to free @data, or %NULL
 209  *
 210  * Creates a new #GMemoryInputStream with data in memory of a given size.
 211  *
 212  * Returns: new #GInputStream read from @data of @len bytes.
 213  **/
 214 GInputStream *
 215 g_memory_input_stream_new_from_data (const void     *data,
 216                                      gssize          len,
 217                                      GDestroyNotify  destroy)
 218 {
 219   GInputStream *stream;
 220
 221   stream = g_memory_input_stream_new ();
 222
 223   g_memory_input_stream_add_data (G_MEMORY_INPUT_STREAM (stream),
 224                                   data, len, destroy);
 225
 226   return stream;
 227 }
 228
 229 /**
 230  * g_memory_input_stream_add_data:
 231  * @stream: a #GMemoryInputStream
 232  * @data: (array length=len) (element-type guint8): input data
 233  * @len: length of the data, may be -1 if @data is a nul-terminated string
 234  * @destroy: (allow-none): function that is called to free @data, or %NULL
 235  *
 236  * Appends @data to data that can be read from the input stream
 237  */
 238 void
 239 g_memory_input_stream_add_data (GMemoryInputStream *stream,
 240                                 const void         *data,
 241                                 gssize              len,
 242                                 GDestroyNotify      destroy)
 243 {
 244   GMemoryInputStreamPrivate *priv;
 245   Chunk *chunk;
 246
 247   g_return_if_fail (G_IS_MEMORY_INPUT_STREAM (stream));
 248   g_return_if_fail (data != NULL);
 249
 250   priv = stream->priv;
 251
 252   if (len == -1)
 253     len = strlen (data);
 254
 255   chunk = g_slice_new (Chunk);
 256   chunk->data = (guint8 *)data;
 257   chunk->len = len;
 258   chunk->destroy = destroy;
 259
 260   priv->chunks = g_slist_append (priv->chunks, chunk);
 261   priv->len += chunk->len;
 262 }
 263
 264 static gssize
 265 g_memory_input_stream_read (GInputStream  *stream,
 266                             void          *buffer,
 267                             gsize          count,
 268                             GCancellable  *cancellable,
 269                             GError       **error)
 270 {
 271   GMemoryInputStream *memory_stream;
 272   GMemoryInputStreamPrivate *priv;
 273   GSList *l;
 274   Chunk *chunk;
 275   gsize offset, start, rest, size;
 276
 277   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 278   priv = memory_stream->priv;
 279
 280   count = MIN (count, priv->len - priv->pos);
 281
 282   offset = 0;
 283   for (l = priv->chunks; l; l = l->next)
 284     {
 285       chunk = (Chunk *)l->data;
 286
 287       if (offset + chunk->len > priv->pos)
 288         break;
 289
 290       offset += chunk->len;
 291     }
 292
 293   start = priv->pos - offset;
 294   rest = count;
 295
 296   for (; l && rest > 0; l = l->next)
 297     {
 298       chunk = (Chunk *)l->data;
 299       size = MIN (rest, chunk->len - start);
 300
 301       memcpy ((guint8 *)buffer + (count - rest), chunk->data + start, size);
 302       rest -= size;
 303
 304       start = 0;
 305     }
 306
 307   priv->pos += count;
 308
 309   return count;
 310 }
 311
 312 static gssize
 313 g_memory_input_stream_skip (GInputStream  *stream,
 314                             gsize          count,
 315                             GCancellable  *cancellable,
 316                             GError       **error)
 317 {
 318   GMemoryInputStream *memory_stream;
 319   GMemoryInputStreamPrivate *priv;
 320
 321   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 322   priv = memory_stream->priv;
 323
 324   count = MIN (count, priv->len - priv->pos);
 325   priv->pos += count;
 326
 327   return count;
 328 }
 329
 330 static gboolean
 331 g_memory_input_stream_close (GInputStream  *stream,
 332                              GCancellable  *cancellable,
 333                              GError       **error)
 334 {
 335   return TRUE;
 336 }
 337
 338 static void
 339 g_memory_input_stream_read_async (GInputStream        *stream,
 340                                   void                *buffer,
 341                                   gsize                count,
 342                                   int                  io_priority,
 343                                   GCancellable        *cancellable,
 344                                   GAsyncReadyCallback  callback,
 345                                   gpointer             user_data)
 346 {
 347   GSimpleAsyncResult *simple;
 348   gssize nread;
 349
 350   nread = g_memory_input_stream_read (stream, buffer, count, cancellable, NULL);
 351   simple = g_simple_async_result_new (G_OBJECT (stream),
 352                                       callback,
 353                                       user_data,
 354                                       g_memory_input_stream_read_async);
 355   g_simple_async_result_set_op_res_gssize (simple, nread);
 356   g_simple_async_result_complete_in_idle (simple);
 357   g_object_unref (simple);
 358 }
 359
 360 static gssize
 361 g_memory_input_stream_read_finish (GInputStream  *stream,
 362                                    GAsyncResult  *result,
 363                                    GError       **error)
 364 {
 365   GSimpleAsyncResult *simple;
 366   gssize nread;
 367
 368   simple = G_SIMPLE_ASYNC_RESULT (result);
 369   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_memory_input_stream_read_async);
 370
 371   nread = g_simple_async_result_get_op_res_gssize (simple);
 372   return nread;
 373 }
 374
 375 static void
 376 g_memory_input_stream_skip_async (GInputStream        *stream,
 377                                   gsize                count,
 378                                   int                  io_priority,
 379                                   GCancellable        *cancellable,
 380                                   GAsyncReadyCallback  callback,
 381                                   gpointer             user_data)
 382 {
 383   GSimpleAsyncResult *simple;
 384   gssize nskipped;
 385
 386   nskipped = g_memory_input_stream_skip (stream, count, cancellable, NULL);
 387   simple = g_simple_async_result_new (G_OBJECT (stream),
 388                                       callback,
 389                                       user_data,
 390                                       g_memory_input_stream_skip_async);
 391   g_simple_async_result_set_op_res_gssize (simple, nskipped);
 392   g_simple_async_result_complete_in_idle (simple);
 393   g_object_unref (simple);
 394 }
 395
 396 static gssize
 397 g_memory_input_stream_skip_finish (GInputStream  *stream,
 398                                    GAsyncResult  *result,
 399                                    GError       **error)
 400 {
 401   GSimpleAsyncResult *simple;
 402   gssize nskipped;
 403
 404   simple = G_SIMPLE_ASYNC_RESULT (result);
 405   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_memory_input_stream_skip_async);
 406
 407   nskipped = g_simple_async_result_get_op_res_gssize (simple);
 408   return nskipped;
 409 }
 410
 411 static void
 412 g_memory_input_stream_close_async (GInputStream        *stream,
 413                                    int                  io_priority,
 414                                    GCancellable        *cancellable,
 415                                    GAsyncReadyCallback  callback,
 416                                    gpointer             user_data)
 417 {
 418   GSimpleAsyncResult *simple;
 419
 420   simple = g_simple_async_result_new (G_OBJECT (stream),
 421                                       callback,
 422                                       user_data,
 423                                       g_memory_input_stream_close_async);
 424   g_simple_async_result_complete_in_idle (simple);
 425   g_object_unref (simple);
 426 }
 427
 428 static gboolean
 429 g_memory_input_stream_close_finish (GInputStream  *stream,
 430                                     GAsyncResult  *result,
 431                                     GError       **error)
 432 {
 433   return TRUE;
 434 }
 435
 436 static goffset
 437 g_memory_input_stream_tell (GSeekable *seekable)
 438 {
 439   GMemoryInputStream *memory_stream;
 440   GMemoryInputStreamPrivate *priv;
 441
 442   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 443   priv = memory_stream->priv;
 444
 445   return priv->pos;
 446 }
 447
 448 static
 449 gboolean g_memory_input_stream_can_seek (GSeekable *seekable)
 450 {
 451   return TRUE;
 452 }
 453
 454 static gboolean
 455 g_memory_input_stream_seek (GSeekable     *seekable,
 456                             goffset        offset,
 457                             GSeekType      type,
 458                             GCancellable  *cancellable,
 459                             GError       **error)
 460 {
 461   GMemoryInputStream *memory_stream;
 462   GMemoryInputStreamPrivate *priv;
 463   goffset absolute;
 464
 465   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 466   priv = memory_stream->priv;
 467
 468   switch (type)
 469     {
 470     case G_SEEK_CUR:
 471       absolute = priv->pos + offset;
 472       break;
 473
 474     case G_SEEK_SET:
 475       absolute = offset;
 476       break;
 477
 478     case G_SEEK_END:
 479       absolute = priv->len + offset;
 480       break;
 481
 482     default:
 483       g_set_error_literal (error,
 484                            G_IO_ERROR,
 485                            G_IO_ERROR_INVALID_ARGUMENT,
 486                            _("Invalid GSeekType supplied"));
 487
 488       return FALSE;
 489     }
 490
 491   if (absolute < 0 || absolute > priv->len)
 492     {
 493       g_set_error_literal (error,
 494                            G_IO_ERROR,
 495                            G_IO_ERROR_INVALID_ARGUMENT,
 496                            _("Invalid seek request"));
 497       return FALSE;
 498     }
 499
 500   priv->pos = absolute;
 501
 502   return TRUE;
 503 }
 504
 505 static gboolean
 506 g_memory_input_stream_can_truncate (GSeekable *seekable)
 507 {
 508   return FALSE;
 509 }
 510
 511 static gboolean
 512 g_memory_input_stream_truncate (GSeekable     *seekable,
 513                                 goffset        offset,
 514                                 GCancellable  *cancellable,
 515                                 GError       **error)
 516 {
 517   g_set_error_literal (error,
 518                        G_IO_ERROR,
 519                        G_IO_ERROR_NOT_SUPPORTED,
 520                        _("Cannot truncate GMemoryInputStream"));
 521   return FALSE;
 522 }