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 "gpollableinputstream.h"
  26 #include "ginputstream.h"
  27 #include "gseekable.h"
  28 #include "string.h"
  29 #include "gsimpleasyncresult.h"
  30 #include "gioerror.h"
  31 #include "glibintl.h"
  32
  33
  34 /**
  35  * SECTION:gmemoryinputstream
  36  * @short_description: Streaming input operations on memory chunks
  37  * @include: gio/gio.h
  38  * @see_also: #GMemoryOutputStream
  39  *
  40  * #GMemoryInputStream is a class for using arbitrary
  41  * memory chunks as input for GIO streaming input operations.
  42  *
  43  * As of GLib 2.34, #GMemoryInputStream implements
  44  * #GPollableInputStream.
  45  */
  46
  47 typedef struct _Chunk Chunk;
  48
  49 struct _Chunk {
  50   guint8         *data;
  51   gsize           len;
  52   GDestroyNotify  destroy;
  53 };
  54
  55 struct _GMemoryInputStreamPrivate {
  56   GSList *chunks;
  57   gsize   len;
  58   gsize   pos;
  59 };
  60
  61 static gssize   g_memory_input_stream_read         (GInputStream         *stream,
  62                                                     void                 *buffer,
  63                                                     gsize                 count,
  64                                                     GCancellable         *cancellable,
  65                                                     GError              **error);
  66 static gssize   g_memory_input_stream_skip         (GInputStream         *stream,
  67                                                     gsize                 count,
  68                                                     GCancellable         *cancellable,
  69                                                     GError              **error);
  70 static gboolean g_memory_input_stream_close        (GInputStream         *stream,
  71                                                     GCancellable         *cancellable,
  72                                                     GError              **error);
  73 static void     g_memory_input_stream_skip_async   (GInputStream         *stream,
  74                                                     gsize                 count,
  75                                                     int                   io_priority,
  76                                                     GCancellable         *cancellabl,
  77                                                     GAsyncReadyCallback   callback,
  78                                                     gpointer              datae);
  79 static gssize   g_memory_input_stream_skip_finish  (GInputStream         *stream,
  80                                                     GAsyncResult         *result,
  81                                                     GError              **error);
  82 static void     g_memory_input_stream_close_async  (GInputStream         *stream,
  83                                                     int                   io_priority,
  84                                                     GCancellable         *cancellabl,
  85                                                     GAsyncReadyCallback   callback,
  86                                                     gpointer              data);
  87 static gboolean g_memory_input_stream_close_finish (GInputStream         *stream,
  88                                                     GAsyncResult         *result,
  89                                                     GError              **error);
  90
  91 static void     g_memory_input_stream_seekable_iface_init (GSeekableIface  *iface);
  92 static goffset  g_memory_input_stream_tell                (GSeekable       *seekable);
  93 static gboolean g_memory_input_stream_can_seek            (GSeekable       *seekable);
  94 static gboolean g_memory_input_stream_seek                (GSeekable       *seekable,
  95                                                            goffset          offset,
  96                                                            GSeekType        type,
  97                                                            GCancellable    *cancellable,
  98                                                            GError         **error);
  99 static gboolean g_memory_input_stream_can_truncate        (GSeekable       *seekable);
 100 static gboolean g_memory_input_stream_truncate            (GSeekable       *seekable,
 101                                                            goffset          offset,
 102                                                            GCancellable    *cancellable,
 103                                                            GError         **error);
 104
 105 static void     g_memory_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);
 106 static gboolean g_memory_input_stream_is_readable         (GPollableInputStream *stream);
 107 static GSource *g_memory_input_stream_create_source       (GPollableInputStream *stream,
 108                                                            GCancellable          *cancellable);
 109
 110 static void     g_memory_input_stream_finalize            (GObject         *object);
 111
 112 G_DEFINE_TYPE_WITH_CODE (GMemoryInputStream, g_memory_input_stream, G_TYPE_INPUT_STREAM,
 113                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
 114                                                 g_memory_input_stream_seekable_iface_init);
 115                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,
 116                                                 g_memory_input_stream_pollable_iface_init);
 117                          )
 118
 119
 120 static void
 121 g_memory_input_stream_class_init (GMemoryInputStreamClass *klass)
 122 {
 123   GObjectClass *object_class;
 124   GInputStreamClass *istream_class;
 125
 126   g_type_class_add_private (klass, sizeof (GMemoryInputStreamPrivate));
 127
 128   object_class = G_OBJECT_CLASS (klass);
 129   object_class->finalize     = g_memory_input_stream_finalize;
 130
 131   istream_class = G_INPUT_STREAM_CLASS (klass);
 132   istream_class->read_fn  = g_memory_input_stream_read;
 133   istream_class->skip  = g_memory_input_stream_skip;
 134   istream_class->close_fn = g_memory_input_stream_close;
 135
 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 {
 145   Chunk *chunk = data;
 146
 147   if (chunk->destroy)
 148     chunk->destroy (chunk->data);
 149
 150   g_slice_free (Chunk, chunk);
 151 }
 152
 153 static void
 154 g_memory_input_stream_finalize (GObject *object)
 155 {
 156   GMemoryInputStream        *stream;
 157   GMemoryInputStreamPrivate *priv;
 158
 159   stream = G_MEMORY_INPUT_STREAM (object);
 160   priv = stream->priv;
 161
 162   g_slist_free_full (priv->chunks, free_chunk);
 163
 164   G_OBJECT_CLASS (g_memory_input_stream_parent_class)->finalize (object);
 165 }
 166
 167 static void
 168 g_memory_input_stream_seekable_iface_init (GSeekableIface *iface)
 169 {
 170   iface->tell         = g_memory_input_stream_tell;
 171   iface->can_seek     = g_memory_input_stream_can_seek;
 172   iface->seek         = g_memory_input_stream_seek;
 173   iface->can_truncate = g_memory_input_stream_can_truncate;
 174   iface->truncate_fn  = g_memory_input_stream_truncate;
 175 }
 176
 177 static void
 178 g_memory_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 179 {
 180   iface->is_readable   = g_memory_input_stream_is_readable;
 181   iface->create_source = g_memory_input_stream_create_source;
 182 }
 183
 184 static void
 185 g_memory_input_stream_init (GMemoryInputStream *stream)
 186 {
 187   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 188                                               G_TYPE_MEMORY_INPUT_STREAM,
 189                                               GMemoryInputStreamPrivate);
 190 }
 191
 192 /**
 193  * g_memory_input_stream_new:
 194  *
 195  * Creates a new empty #GMemoryInputStream.
 196  *
 197  * Returns: a new #GInputStream
 198  */
 199 GInputStream *
 200 g_memory_input_stream_new (void)
 201 {
 202   GInputStream *stream;
 203
 204   stream = g_object_new (G_TYPE_MEMORY_INPUT_STREAM, NULL);
 205
 206   return stream;
 207 }
 208
 209 /**
 210  * g_memory_input_stream_new_from_data:
 211  * @data: (array length=len) (element-type guint8) (transfer full): input data
 212  * @len: length of the data, may be -1 if @data is a nul-terminated string
 213  * @destroy: (allow-none): function that is called to free @data, or %NULL
 214  *
 215  * Creates a new #GMemoryInputStream with data in memory of a given size.
 216  *
 217  * Returns: new #GInputStream read from @data of @len bytes.
 218  **/
 219 GInputStream *
 220 g_memory_input_stream_new_from_data (const void     *data,
 221                                      gssize          len,
 222                                      GDestroyNotify  destroy)
 223 {
 224   GInputStream *stream;
 225
 226   stream = g_memory_input_stream_new ();
 227
 228   g_memory_input_stream_add_data (G_MEMORY_INPUT_STREAM (stream),
 229                                   data, len, destroy);
 230
 231   return stream;
 232 }
 233
 234 /**
 235  * g_memory_input_stream_add_data:
 236  * @stream: a #GMemoryInputStream
 237  * @data: (array length=len) (element-type guint8) (transfer full): input data
 238  * @len: length of the data, may be -1 if @data is a nul-terminated string
 239  * @destroy: (allow-none): function that is called to free @data, or %NULL
 240  *
 241  * Appends @data to data that can be read from the input stream
 242  */
 243 void
 244 g_memory_input_stream_add_data (GMemoryInputStream *stream,
 245                                 const void         *data,
 246                                 gssize              len,
 247                                 GDestroyNotify      destroy)
 248 {
 249   GMemoryInputStreamPrivate *priv;
 250   Chunk *chunk;
 251
 252   g_return_if_fail (G_IS_MEMORY_INPUT_STREAM (stream));
 253   g_return_if_fail (data != NULL);
 254
 255   priv = stream->priv;
 256
 257   if (len == -1)
 258     len = strlen (data);
 259
 260   chunk = g_slice_new (Chunk);
 261   chunk->data = (guint8 *)data;
 262   chunk->len = len;
 263   chunk->destroy = destroy;
 264
 265   priv->chunks = g_slist_append (priv->chunks, chunk);
 266   priv->len += chunk->len;
 267 }
 268
 269 static gssize
 270 g_memory_input_stream_read (GInputStream  *stream,
 271                             void          *buffer,
 272                             gsize          count,
 273                             GCancellable  *cancellable,
 274                             GError       **error)
 275 {
 276   GMemoryInputStream *memory_stream;
 277   GMemoryInputStreamPrivate *priv;
 278   GSList *l;
 279   Chunk *chunk;
 280   gsize offset, start, rest, size;
 281
 282   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 283   priv = memory_stream->priv;
 284
 285   count = MIN (count, priv->len - priv->pos);
 286
 287   offset = 0;
 288   for (l = priv->chunks; l; l = l->next)
 289     {
 290       chunk = (Chunk *)l->data;
 291
 292       if (offset + chunk->len > priv->pos)
 293         break;
 294
 295       offset += chunk->len;
 296     }
 297
 298   start = priv->pos - offset;
 299   rest = count;
 300
 301   for (; l && rest > 0; l = l->next)
 302     {
 303       chunk = (Chunk *)l->data;
 304       size = MIN (rest, chunk->len - start);
 305
 306       memcpy ((guint8 *)buffer + (count - rest), chunk->data + start, size);
 307       rest -= size;
 308
 309       start = 0;
 310     }
 311
 312   priv->pos += count;
 313
 314   return count;
 315 }
 316
 317 static gssize
 318 g_memory_input_stream_skip (GInputStream  *stream,
 319                             gsize          count,
 320                             GCancellable  *cancellable,
 321                             GError       **error)
 322 {
 323   GMemoryInputStream *memory_stream;
 324   GMemoryInputStreamPrivate *priv;
 325
 326   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 327   priv = memory_stream->priv;
 328
 329   count = MIN (count, priv->len - priv->pos);
 330   priv->pos += count;
 331
 332   return count;
 333 }
 334
 335 static gboolean
 336 g_memory_input_stream_close (GInputStream  *stream,
 337                              GCancellable  *cancellable,
 338                              GError       **error)
 339 {
 340   return TRUE;
 341 }
 342
 343 static void
 344 g_memory_input_stream_skip_async (GInputStream        *stream,
 345                                   gsize                count,
 346                                   int                  io_priority,
 347                                   GCancellable        *cancellable,
 348                                   GAsyncReadyCallback  callback,
 349                                   gpointer             user_data)
 350 {
 351   GSimpleAsyncResult *simple;
 352   gssize nskipped;
 353
 354   nskipped = g_input_stream_skip (stream, count, cancellable, NULL);
 355   simple = g_simple_async_result_new (G_OBJECT (stream),
 356                                       callback,
 357                                       user_data,
 358                                       g_memory_input_stream_skip_async);
 359   g_simple_async_result_set_op_res_gssize (simple, nskipped);
 360   g_simple_async_result_complete_in_idle (simple);
 361   g_object_unref (simple);
 362 }
 363
 364 static gssize
 365 g_memory_input_stream_skip_finish (GInputStream  *stream,
 366                                    GAsyncResult  *result,
 367                                    GError       **error)
 368 {
 369   GSimpleAsyncResult *simple;
 370   gssize nskipped;
 371
 372   simple = G_SIMPLE_ASYNC_RESULT (result);
 373   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_memory_input_stream_skip_async);
 374
 375   nskipped = g_simple_async_result_get_op_res_gssize (simple);
 376   return nskipped;
 377 }
 378
 379 static void
 380 g_memory_input_stream_close_async (GInputStream        *stream,
 381                                    int                  io_priority,
 382                                    GCancellable        *cancellable,
 383                                    GAsyncReadyCallback  callback,
 384                                    gpointer             user_data)
 385 {
 386   GSimpleAsyncResult *simple;
 387
 388   simple = g_simple_async_result_new (G_OBJECT (stream),
 389                                       callback,
 390                                       user_data,
 391                                       g_memory_input_stream_close_async);
 392   g_simple_async_result_complete_in_idle (simple);
 393   g_object_unref (simple);
 394 }
 395
 396 static gboolean
 397 g_memory_input_stream_close_finish (GInputStream  *stream,
 398                                     GAsyncResult  *result,
 399                                     GError       **error)
 400 {
 401   return TRUE;
 402 }
 403
 404 static goffset
 405 g_memory_input_stream_tell (GSeekable *seekable)
 406 {
 407   GMemoryInputStream *memory_stream;
 408   GMemoryInputStreamPrivate *priv;
 409
 410   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 411   priv = memory_stream->priv;
 412
 413   return priv->pos;
 414 }
 415
 416 static
 417 gboolean g_memory_input_stream_can_seek (GSeekable *seekable)
 418 {
 419   return TRUE;
 420 }
 421
 422 static gboolean
 423 g_memory_input_stream_seek (GSeekable     *seekable,
 424                             goffset        offset,
 425                             GSeekType      type,
 426                             GCancellable  *cancellable,
 427                             GError       **error)
 428 {
 429   GMemoryInputStream *memory_stream;
 430   GMemoryInputStreamPrivate *priv;
 431   goffset absolute;
 432
 433   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 434   priv = memory_stream->priv;
 435
 436   switch (type)
 437     {
 438     case G_SEEK_CUR:
 439       absolute = priv->pos + offset;
 440       break;
 441
 442     case G_SEEK_SET:
 443       absolute = offset;
 444       break;
 445
 446     case G_SEEK_END:
 447       absolute = priv->len + offset;
 448       break;
 449
 450     default:
 451       g_set_error_literal (error,
 452                            G_IO_ERROR,
 453                            G_IO_ERROR_INVALID_ARGUMENT,
 454                            _("Invalid GSeekType supplied"));
 455
 456       return FALSE;
 457     }
 458
 459   if (absolute < 0 || absolute > priv->len)
 460     {
 461       g_set_error_literal (error,
 462                            G_IO_ERROR,
 463                            G_IO_ERROR_INVALID_ARGUMENT,
 464                            _("Invalid seek request"));
 465       return FALSE;
 466     }
 467
 468   priv->pos = absolute;
 469
 470   return TRUE;
 471 }
 472
 473 static gboolean
 474 g_memory_input_stream_can_truncate (GSeekable *seekable)
 475 {
 476   return FALSE;
 477 }
 478
 479 static gboolean
 480 g_memory_input_stream_truncate (GSeekable     *seekable,
 481                                 goffset        offset,
 482                                 GCancellable  *cancellable,
 483                                 GError       **error)
 484 {
 485   g_set_error_literal (error,
 486                        G_IO_ERROR,
 487                        G_IO_ERROR_NOT_SUPPORTED,
 488                        _("Cannot truncate GMemoryInputStream"));
 489   return FALSE;
 490 }
 491
 492 static gboolean
 493 g_memory_input_stream_is_readable (GPollableInputStream *stream)
 494 {
 495   return TRUE;
 496 }
 497
 498 static GSource *
 499 g_memory_input_stream_create_source (GPollableInputStream *stream,
 500                                      GCancellable         *cancellable)
 501 {
 502   GSource *base_source, *pollable_source;
 503
 504   base_source = g_timeout_source_new (0);
 505   pollable_source = g_pollable_source_new_full (stream, base_source,
 506                                                 cancellable);
 507   g_source_unref (base_source);
 508
 509   return pollable_source;
 510 }