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_free_full (priv->chunks, free_chunk);
 164
 165   G_OBJECT_CLASS (g_memory_input_stream_parent_class)->finalize (object);
 166 }
 167
 168 static void
 169 g_memory_input_stream_seekable_iface_init (GSeekableIface *iface)
 170 {
 171   iface->tell         = g_memory_input_stream_tell;
 172   iface->can_seek     = g_memory_input_stream_can_seek;
 173   iface->seek         = g_memory_input_stream_seek;
 174   iface->can_truncate = g_memory_input_stream_can_truncate;
 175   iface->truncate_fn  = g_memory_input_stream_truncate;
 176 }
 177
 178 static void
 179 g_memory_input_stream_init (GMemoryInputStream *stream)
 180 {
 181   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 182                                               G_TYPE_MEMORY_INPUT_STREAM,
 183                                               GMemoryInputStreamPrivate);
 184 }
 185
 186 /**
 187  * g_memory_input_stream_new:
 188  *
 189  * Creates a new empty #GMemoryInputStream.
 190  *
 191  * Returns: a new #GInputStream
 192  */
 193 GInputStream *
 194 g_memory_input_stream_new (void)
 195 {
 196   GInputStream *stream;
 197
 198   stream = g_object_new (G_TYPE_MEMORY_INPUT_STREAM, NULL);
 199
 200   return stream;
 201 }
 202
 203 /**
 204  * g_memory_input_stream_new_from_data:
 205  * @data: (array length=len) (element-type guint8) (transfer full): input data
 206  * @len: length of the data, may be -1 if @data is a nul-terminated string
 207  * @destroy: (allow-none): function that is called to free @data, or %NULL
 208  *
 209  * Creates a new #GMemoryInputStream with data in memory of a given size.
 210  *
 211  * Returns: new #GInputStream read from @data of @len bytes.
 212  **/
 213 GInputStream *
 214 g_memory_input_stream_new_from_data (const void     *data,
 215                                      gssize          len,
 216                                      GDestroyNotify  destroy)
 217 {
 218   GInputStream *stream;
 219
 220   stream = g_memory_input_stream_new ();
 221
 222   g_memory_input_stream_add_data (G_MEMORY_INPUT_STREAM (stream),
 223                                   data, len, destroy);
 224
 225   return stream;
 226 }
 227
 228 /**
 229  * g_memory_input_stream_add_data:
 230  * @stream: a #GMemoryInputStream
 231  * @data: (array length=len) (element-type guint8) (transfer full): input data
 232  * @len: length of the data, may be -1 if @data is a nul-terminated string
 233  * @destroy: (allow-none): function that is called to free @data, or %NULL
 234  *
 235  * Appends @data to data that can be read from the input stream
 236  */
 237 void
 238 g_memory_input_stream_add_data (GMemoryInputStream *stream,
 239                                 const void         *data,
 240                                 gssize              len,
 241                                 GDestroyNotify      destroy)
 242 {
 243   GMemoryInputStreamPrivate *priv;
 244   Chunk *chunk;
 245
 246   g_return_if_fail (G_IS_MEMORY_INPUT_STREAM (stream));
 247   g_return_if_fail (data != NULL);
 248
 249   priv = stream->priv;
 250
 251   if (len == -1)
 252     len = strlen (data);
 253
 254   chunk = g_slice_new (Chunk);
 255   chunk->data = (guint8 *)data;
 256   chunk->len = len;
 257   chunk->destroy = destroy;
 258
 259   priv->chunks = g_slist_append (priv->chunks, chunk);
 260   priv->len += chunk->len;
 261 }
 262
 263 static gssize
 264 g_memory_input_stream_read (GInputStream  *stream,
 265                             void          *buffer,
 266                             gsize          count,
 267                             GCancellable  *cancellable,
 268                             GError       **error)
 269 {
 270   GMemoryInputStream *memory_stream;
 271   GMemoryInputStreamPrivate *priv;
 272   GSList *l;
 273   Chunk *chunk;
 274   gsize offset, start, rest, size;
 275
 276   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 277   priv = memory_stream->priv;
 278
 279   count = MIN (count, priv->len - priv->pos);
 280
 281   offset = 0;
 282   for (l = priv->chunks; l; l = l->next)
 283     {
 284       chunk = (Chunk *)l->data;
 285
 286       if (offset + chunk->len > priv->pos)
 287         break;
 288
 289       offset += chunk->len;
 290     }
 291
 292   start = priv->pos - offset;
 293   rest = count;
 294
 295   for (; l && rest > 0; l = l->next)
 296     {
 297       chunk = (Chunk *)l->data;
 298       size = MIN (rest, chunk->len - start);
 299
 300       memcpy ((guint8 *)buffer + (count - rest), chunk->data + start, size);
 301       rest -= size;
 302
 303       start = 0;
 304     }
 305
 306   priv->pos += count;
 307
 308   return count;
 309 }
 310
 311 static gssize
 312 g_memory_input_stream_skip (GInputStream  *stream,
 313                             gsize          count,
 314                             GCancellable  *cancellable,
 315                             GError       **error)
 316 {
 317   GMemoryInputStream *memory_stream;
 318   GMemoryInputStreamPrivate *priv;
 319
 320   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 321   priv = memory_stream->priv;
 322
 323   count = MIN (count, priv->len - priv->pos);
 324   priv->pos += count;
 325
 326   return count;
 327 }
 328
 329 static gboolean
 330 g_memory_input_stream_close (GInputStream  *stream,
 331                              GCancellable  *cancellable,
 332                              GError       **error)
 333 {
 334   return TRUE;
 335 }
 336
 337 static void
 338 g_memory_input_stream_read_async (GInputStream        *stream,
 339                                   void                *buffer,
 340                                   gsize                count,
 341                                   int                  io_priority,
 342                                   GCancellable        *cancellable,
 343                                   GAsyncReadyCallback  callback,
 344                                   gpointer             user_data)
 345 {
 346   GSimpleAsyncResult *simple;
 347   GError *error = NULL;
 348   gssize nread;
 349
 350   nread = G_INPUT_STREAM_GET_CLASS (stream)->read_fn (stream,
 351                                                       buffer,
 352                                                       count,
 353                                                       cancellable,
 354                                                       &error);
 355   simple = g_simple_async_result_new (G_OBJECT (stream),
 356                                       callback,
 357                                       user_data,
 358                                       g_memory_input_stream_read_async);
 359   if (error)
 360     g_simple_async_result_take_error (simple, error);
 361   else
 362     g_simple_async_result_set_op_res_gssize (simple, nread);
 363   g_simple_async_result_complete_in_idle (simple);
 364   g_object_unref (simple);
 365 }
 366
 367 static gssize
 368 g_memory_input_stream_read_finish (GInputStream  *stream,
 369                                    GAsyncResult  *result,
 370                                    GError       **error)
 371 {
 372   GSimpleAsyncResult *simple;
 373   gssize nread;
 374
 375   simple = G_SIMPLE_ASYNC_RESULT (result);
 376   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_memory_input_stream_read_async);
 377
 378   nread = g_simple_async_result_get_op_res_gssize (simple);
 379   return nread;
 380 }
 381
 382 static void
 383 g_memory_input_stream_skip_async (GInputStream        *stream,
 384                                   gsize                count,
 385                                   int                  io_priority,
 386                                   GCancellable        *cancellable,
 387                                   GAsyncReadyCallback  callback,
 388                                   gpointer             user_data)
 389 {
 390   GSimpleAsyncResult *simple;
 391   gssize nskipped;
 392
 393   nskipped = g_input_stream_skip (stream, count, cancellable, NULL);
 394   simple = g_simple_async_result_new (G_OBJECT (stream),
 395                                       callback,
 396                                       user_data,
 397                                       g_memory_input_stream_skip_async);
 398   g_simple_async_result_set_op_res_gssize (simple, nskipped);
 399   g_simple_async_result_complete_in_idle (simple);
 400   g_object_unref (simple);
 401 }
 402
 403 static gssize
 404 g_memory_input_stream_skip_finish (GInputStream  *stream,
 405                                    GAsyncResult  *result,
 406                                    GError       **error)
 407 {
 408   GSimpleAsyncResult *simple;
 409   gssize nskipped;
 410
 411   simple = G_SIMPLE_ASYNC_RESULT (result);
 412   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_memory_input_stream_skip_async);
 413
 414   nskipped = g_simple_async_result_get_op_res_gssize (simple);
 415   return nskipped;
 416 }
 417
 418 static void
 419 g_memory_input_stream_close_async (GInputStream        *stream,
 420                                    int                  io_priority,
 421                                    GCancellable        *cancellable,
 422                                    GAsyncReadyCallback  callback,
 423                                    gpointer             user_data)
 424 {
 425   GSimpleAsyncResult *simple;
 426
 427   simple = g_simple_async_result_new (G_OBJECT (stream),
 428                                       callback,
 429                                       user_data,
 430                                       g_memory_input_stream_close_async);
 431   g_simple_async_result_complete_in_idle (simple);
 432   g_object_unref (simple);
 433 }
 434
 435 static gboolean
 436 g_memory_input_stream_close_finish (GInputStream  *stream,
 437                                     GAsyncResult  *result,
 438                                     GError       **error)
 439 {
 440   return TRUE;
 441 }
 442
 443 static goffset
 444 g_memory_input_stream_tell (GSeekable *seekable)
 445 {
 446   GMemoryInputStream *memory_stream;
 447   GMemoryInputStreamPrivate *priv;
 448
 449   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 450   priv = memory_stream->priv;
 451
 452   return priv->pos;
 453 }
 454
 455 static
 456 gboolean g_memory_input_stream_can_seek (GSeekable *seekable)
 457 {
 458   return TRUE;
 459 }
 460
 461 static gboolean
 462 g_memory_input_stream_seek (GSeekable     *seekable,
 463                             goffset        offset,
 464                             GSeekType      type,
 465                             GCancellable  *cancellable,
 466                             GError       **error)
 467 {
 468   GMemoryInputStream *memory_stream;
 469   GMemoryInputStreamPrivate *priv;
 470   goffset absolute;
 471
 472   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 473   priv = memory_stream->priv;
 474
 475   switch (type)
 476     {
 477     case G_SEEK_CUR:
 478       absolute = priv->pos + offset;
 479       break;
 480
 481     case G_SEEK_SET:
 482       absolute = offset;
 483       break;
 484
 485     case G_SEEK_END:
 486       absolute = priv->len + offset;
 487       break;
 488
 489     default:
 490       g_set_error_literal (error,
 491                            G_IO_ERROR,
 492                            G_IO_ERROR_INVALID_ARGUMENT,
 493                            _("Invalid GSeekType supplied"));
 494
 495       return FALSE;
 496     }
 497
 498   if (absolute < 0 || absolute > priv->len)
 499     {
 500       g_set_error_literal (error,
 501                            G_IO_ERROR,
 502                            G_IO_ERROR_INVALID_ARGUMENT,
 503                            _("Invalid seek request"));
 504       return FALSE;
 505     }
 506
 507   priv->pos = absolute;
 508
 509   return TRUE;
 510 }
 511
 512 static gboolean
 513 g_memory_input_stream_can_truncate (GSeekable *seekable)
 514 {
 515   return FALSE;
 516 }
 517
 518 static gboolean
 519 g_memory_input_stream_truncate (GSeekable     *seekable,
 520                                 goffset        offset,
 521                                 GCancellable  *cancellable,
 522                                 GError       **error)
 523 {
 524   g_set_error_literal (error,
 525                        G_IO_ERROR,
 526                        G_IO_ERROR_NOT_SUPPORTED,
 527                        _("Cannot truncate GMemoryInputStream"));
 528   return FALSE;
 529 }