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 "gtask.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 struct _GMemoryInputStreamPrivate {
  48   GSList *chunks;
  49   gsize   len;
  50   gsize   pos;
  51 };
  52
  53 static gssize   g_memory_input_stream_read         (GInputStream         *stream,
  54                                                     void                 *buffer,
  55                                                     gsize                 count,
  56                                                     GCancellable         *cancellable,
  57                                                     GError              **error);
  58 static gssize   g_memory_input_stream_skip         (GInputStream         *stream,
  59                                                     gsize                 count,
  60                                                     GCancellable         *cancellable,
  61                                                     GError              **error);
  62 static gboolean g_memory_input_stream_close        (GInputStream         *stream,
  63                                                     GCancellable         *cancellable,
  64                                                     GError              **error);
  65 static void     g_memory_input_stream_skip_async   (GInputStream         *stream,
  66                                                     gsize                 count,
  67                                                     int                   io_priority,
  68                                                     GCancellable         *cancellabl,
  69                                                     GAsyncReadyCallback   callback,
  70                                                     gpointer              datae);
  71 static gssize   g_memory_input_stream_skip_finish  (GInputStream         *stream,
  72                                                     GAsyncResult         *result,
  73                                                     GError              **error);
  74 static void     g_memory_input_stream_close_async  (GInputStream         *stream,
  75                                                     int                   io_priority,
  76                                                     GCancellable         *cancellabl,
  77                                                     GAsyncReadyCallback   callback,
  78                                                     gpointer              data);
  79 static gboolean g_memory_input_stream_close_finish (GInputStream         *stream,
  80                                                     GAsyncResult         *result,
  81                                                     GError              **error);
  82
  83 static void     g_memory_input_stream_seekable_iface_init (GSeekableIface  *iface);
  84 static goffset  g_memory_input_stream_tell                (GSeekable       *seekable);
  85 static gboolean g_memory_input_stream_can_seek            (GSeekable       *seekable);
  86 static gboolean g_memory_input_stream_seek                (GSeekable       *seekable,
  87                                                            goffset          offset,
  88                                                            GSeekType        type,
  89                                                            GCancellable    *cancellable,
  90                                                            GError         **error);
  91 static gboolean g_memory_input_stream_can_truncate        (GSeekable       *seekable);
  92 static gboolean g_memory_input_stream_truncate            (GSeekable       *seekable,
  93                                                            goffset          offset,
  94                                                            GCancellable    *cancellable,
  95                                                            GError         **error);
  96
  97 static void     g_memory_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);
  98 static gboolean g_memory_input_stream_is_readable         (GPollableInputStream *stream);
  99 static GSource *g_memory_input_stream_create_source       (GPollableInputStream *stream,
 100                                                            GCancellable          *cancellable);
 101
 102 static void     g_memory_input_stream_finalize            (GObject         *object);
 103
 104 G_DEFINE_TYPE_WITH_CODE (GMemoryInputStream, g_memory_input_stream, G_TYPE_INPUT_STREAM,
 105                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
 106                                                 g_memory_input_stream_seekable_iface_init);
 107                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,
 108                                                 g_memory_input_stream_pollable_iface_init);
 109                          )
 110
 111
 112 static void
 113 g_memory_input_stream_class_init (GMemoryInputStreamClass *klass)
 114 {
 115   GObjectClass *object_class;
 116   GInputStreamClass *istream_class;
 117
 118   g_type_class_add_private (klass, sizeof (GMemoryInputStreamPrivate));
 119
 120   object_class = G_OBJECT_CLASS (klass);
 121   object_class->finalize     = g_memory_input_stream_finalize;
 122
 123   istream_class = G_INPUT_STREAM_CLASS (klass);
 124   istream_class->read_fn  = g_memory_input_stream_read;
 125   istream_class->skip  = g_memory_input_stream_skip;
 126   istream_class->close_fn = g_memory_input_stream_close;
 127
 128   istream_class->skip_async  = g_memory_input_stream_skip_async;
 129   istream_class->skip_finish  = g_memory_input_stream_skip_finish;
 130   istream_class->close_async = g_memory_input_stream_close_async;
 131   istream_class->close_finish = g_memory_input_stream_close_finish;
 132 }
 133
 134 static void
 135 g_memory_input_stream_finalize (GObject *object)
 136 {
 137   GMemoryInputStream        *stream;
 138   GMemoryInputStreamPrivate *priv;
 139
 140   stream = G_MEMORY_INPUT_STREAM (object);
 141   priv = stream->priv;
 142
 143   g_slist_free_full (priv->chunks, (GDestroyNotify)g_bytes_unref);
 144
 145   G_OBJECT_CLASS (g_memory_input_stream_parent_class)->finalize (object);
 146 }
 147
 148 static void
 149 g_memory_input_stream_seekable_iface_init (GSeekableIface *iface)
 150 {
 151   iface->tell         = g_memory_input_stream_tell;
 152   iface->can_seek     = g_memory_input_stream_can_seek;
 153   iface->seek         = g_memory_input_stream_seek;
 154   iface->can_truncate = g_memory_input_stream_can_truncate;
 155   iface->truncate_fn  = g_memory_input_stream_truncate;
 156 }
 157
 158 static void
 159 g_memory_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 160 {
 161   iface->is_readable   = g_memory_input_stream_is_readable;
 162   iface->create_source = g_memory_input_stream_create_source;
 163 }
 164
 165 static void
 166 g_memory_input_stream_init (GMemoryInputStream *stream)
 167 {
 168   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 169                                               G_TYPE_MEMORY_INPUT_STREAM,
 170                                               GMemoryInputStreamPrivate);
 171 }
 172
 173 /**
 174  * g_memory_input_stream_new:
 175  *
 176  * Creates a new empty #GMemoryInputStream.
 177  *
 178  * Returns: a new #GInputStream
 179  */
 180 GInputStream *
 181 g_memory_input_stream_new (void)
 182 {
 183   GInputStream *stream;
 184
 185   stream = g_object_new (G_TYPE_MEMORY_INPUT_STREAM, NULL);
 186
 187   return stream;
 188 }
 189
 190 /**
 191  * g_memory_input_stream_new_from_data:
 192  * @data: (array length=len) (element-type guint8) (transfer full): input data
 193  * @len: length of the data, may be -1 if @data is a nul-terminated string
 194  * @destroy: (allow-none): function that is called to free @data, or %NULL
 195  *
 196  * Creates a new #GMemoryInputStream with data in memory of a given size.
 197  *
 198  * Returns: new #GInputStream read from @data of @len bytes.
 199  **/
 200 GInputStream *
 201 g_memory_input_stream_new_from_data (const void     *data,
 202                                      gssize          len,
 203                                      GDestroyNotify  destroy)
 204 {
 205   GInputStream *stream;
 206
 207   stream = g_memory_input_stream_new ();
 208
 209   g_memory_input_stream_add_data (G_MEMORY_INPUT_STREAM (stream),
 210                                   data, len, destroy);
 211
 212   return stream;
 213 }
 214
 215 /**
 216  * g_memory_input_stream_new_from_bytes:
 217  * @bytes: a #GBytes
 218  *
 219  * Creates a new #GMemoryInputStream with data from the given @bytes.
 220  *
 221  * Returns: new #GInputStream read from @bytes
 222  * Since: 2.34
 223  **/
 224 GInputStream *
 225 g_memory_input_stream_new_from_bytes (GBytes  *bytes)
 226 {
 227
 228   GInputStream *stream;
 229
 230   stream = g_memory_input_stream_new ();
 231
 232   g_memory_input_stream_add_bytes (G_MEMORY_INPUT_STREAM (stream),
 233                                    bytes);
 234
 235   return stream;
 236 }
 237
 238 /**
 239  * g_memory_input_stream_add_data:
 240  * @stream: a #GMemoryInputStream
 241  * @data: (array length=len) (element-type guint8) (transfer full): input data
 242  * @len: length of the data, may be -1 if @data is a nul-terminated string
 243  * @destroy: (allow-none): function that is called to free @data, or %NULL
 244  *
 245  * Appends @data to data that can be read from the input stream
 246  */
 247 void
 248 g_memory_input_stream_add_data (GMemoryInputStream *stream,
 249                                 const void         *data,
 250                                 gssize              len,
 251                                 GDestroyNotify      destroy)
 252 {
 253   GBytes *bytes;
 254
 255   if (len == -1)
 256     len = strlen (data);
 257
 258   /* It's safe to discard the const here because we're chaining the
 259    * destroy callback.
 260    */
 261   bytes = g_bytes_new_with_free_func (data, len, destroy, (void*)data);
 262
 263   g_memory_input_stream_add_bytes (stream, bytes);
 264
 265   g_bytes_unref (bytes);
 266 }
 267
 268 /**
 269  * g_memory_input_stream_add_bytes:
 270  * @stream: a #GMemoryInputStream
 271  * @bytes: input data
 272  *
 273  * Appends @bytes to data that can be read from the input stream.
 274  *
 275  * Since: 2.34
 276  */
 277 void
 278 g_memory_input_stream_add_bytes (GMemoryInputStream *stream,
 279                                  GBytes             *bytes)
 280 {
 281   GMemoryInputStreamPrivate *priv;
 282
 283   g_return_if_fail (G_IS_MEMORY_INPUT_STREAM (stream));
 284   g_return_if_fail (bytes != NULL);
 285
 286   priv = stream->priv;
 287
 288   priv->chunks = g_slist_append (priv->chunks, g_bytes_ref (bytes));
 289   priv->len += g_bytes_get_size (bytes);
 290 }
 291
 292 static gssize
 293 g_memory_input_stream_read (GInputStream  *stream,
 294                             void          *buffer,
 295                             gsize          count,
 296                             GCancellable  *cancellable,
 297                             GError       **error)
 298 {
 299   GMemoryInputStream *memory_stream;
 300   GMemoryInputStreamPrivate *priv;
 301   GSList *l;
 302   GBytes *chunk;
 303   gsize len;
 304   gsize offset, start, rest, size;
 305
 306   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 307   priv = memory_stream->priv;
 308
 309   count = MIN (count, priv->len - priv->pos);
 310
 311   offset = 0;
 312   for (l = priv->chunks; l; l = l->next)
 313     {
 314       chunk = (GBytes *)l->data;
 315       len = g_bytes_get_size (chunk);
 316
 317       if (offset + len > priv->pos)
 318         break;
 319
 320       offset += len;
 321     }
 322
 323   start = priv->pos - offset;
 324   rest = count;
 325
 326   for (; l && rest > 0; l = l->next)
 327     {
 328       const guint8* chunk_data;
 329       chunk = (GBytes *)l->data;
 330
 331       chunk_data = g_bytes_get_data (chunk, &len);
 332
 333       size = MIN (rest, len - start);
 334
 335       memcpy ((guint8 *)buffer + (count - rest), chunk_data + start, size);
 336       rest -= size;
 337
 338       start = 0;
 339     }
 340
 341   priv->pos += count;
 342
 343   return count;
 344 }
 345
 346 static gssize
 347 g_memory_input_stream_skip (GInputStream  *stream,
 348                             gsize          count,
 349                             GCancellable  *cancellable,
 350                             GError       **error)
 351 {
 352   GMemoryInputStream *memory_stream;
 353   GMemoryInputStreamPrivate *priv;
 354
 355   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 356   priv = memory_stream->priv;
 357
 358   count = MIN (count, priv->len - priv->pos);
 359   priv->pos += count;
 360
 361   return count;
 362 }
 363
 364 static gboolean
 365 g_memory_input_stream_close (GInputStream  *stream,
 366                              GCancellable  *cancellable,
 367                              GError       **error)
 368 {
 369   return TRUE;
 370 }
 371
 372 static void
 373 g_memory_input_stream_skip_async (GInputStream        *stream,
 374                                   gsize                count,
 375                                   int                  io_priority,
 376                                   GCancellable        *cancellable,
 377                                   GAsyncReadyCallback  callback,
 378                                   gpointer             user_data)
 379 {
 380   GTask *task;
 381   gssize nskipped;
 382   GError *error = NULL;
 383
 384   nskipped = G_INPUT_STREAM_GET_CLASS (stream)->skip (stream, count, cancellable, &error);
 385   task = g_task_new (stream, cancellable, callback, user_data);
 386   if (error)
 387     g_task_return_error (task, error);
 388   else
 389     g_task_return_int (task, nskipped);
 390   g_object_unref (task);
 391 }
 392
 393 static gssize
 394 g_memory_input_stream_skip_finish (GInputStream  *stream,
 395                                    GAsyncResult  *result,
 396                                    GError       **error)
 397 {
 398   g_return_val_if_fail (g_task_is_valid (result, stream), -1);
 399
 400   return g_task_propagate_int (G_TASK (result), error);
 401 }
 402
 403 static void
 404 g_memory_input_stream_close_async (GInputStream        *stream,
 405                                    int                  io_priority,
 406                                    GCancellable        *cancellable,
 407                                    GAsyncReadyCallback  callback,
 408                                    gpointer             user_data)
 409 {
 410   GTask *task;
 411
 412   task = g_task_new (stream, cancellable, callback, user_data);
 413   g_task_return_boolean (task, TRUE);
 414   g_object_unref (task);
 415 }
 416
 417 static gboolean
 418 g_memory_input_stream_close_finish (GInputStream  *stream,
 419                                     GAsyncResult  *result,
 420                                     GError       **error)
 421 {
 422   return TRUE;
 423 }
 424
 425 static goffset
 426 g_memory_input_stream_tell (GSeekable *seekable)
 427 {
 428   GMemoryInputStream *memory_stream;
 429   GMemoryInputStreamPrivate *priv;
 430
 431   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 432   priv = memory_stream->priv;
 433
 434   return priv->pos;
 435 }
 436
 437 static
 438 gboolean g_memory_input_stream_can_seek (GSeekable *seekable)
 439 {
 440   return TRUE;
 441 }
 442
 443 static gboolean
 444 g_memory_input_stream_seek (GSeekable     *seekable,
 445                             goffset        offset,
 446                             GSeekType      type,
 447                             GCancellable  *cancellable,
 448                             GError       **error)
 449 {
 450   GMemoryInputStream *memory_stream;
 451   GMemoryInputStreamPrivate *priv;
 452   goffset absolute;
 453
 454   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 455   priv = memory_stream->priv;
 456
 457   switch (type)
 458     {
 459     case G_SEEK_CUR:
 460       absolute = priv->pos + offset;
 461       break;
 462
 463     case G_SEEK_SET:
 464       absolute = offset;
 465       break;
 466
 467     case G_SEEK_END:
 468       absolute = priv->len + offset;
 469       break;
 470
 471     default:
 472       g_set_error_literal (error,
 473                            G_IO_ERROR,
 474                            G_IO_ERROR_INVALID_ARGUMENT,
 475                            _("Invalid GSeekType supplied"));
 476
 477       return FALSE;
 478     }
 479
 480   if (absolute < 0 || absolute > priv->len)
 481     {
 482       g_set_error_literal (error,
 483                            G_IO_ERROR,
 484                            G_IO_ERROR_INVALID_ARGUMENT,
 485                            _("Invalid seek request"));
 486       return FALSE;
 487     }
 488
 489   priv->pos = absolute;
 490
 491   return TRUE;
 492 }
 493
 494 static gboolean
 495 g_memory_input_stream_can_truncate (GSeekable *seekable)
 496 {
 497   return FALSE;
 498 }
 499
 500 static gboolean
 501 g_memory_input_stream_truncate (GSeekable     *seekable,
 502                                 goffset        offset,
 503                                 GCancellable  *cancellable,
 504                                 GError       **error)
 505 {
 506   g_set_error_literal (error,
 507                        G_IO_ERROR,
 508                        G_IO_ERROR_NOT_SUPPORTED,
 509                        _("Cannot truncate GMemoryInputStream"));
 510   return FALSE;
 511 }
 512
 513 static gboolean
 514 g_memory_input_stream_is_readable (GPollableInputStream *stream)
 515 {
 516   return TRUE;
 517 }
 518
 519 static GSource *
 520 g_memory_input_stream_create_source (GPollableInputStream *stream,
 521                                      GCancellable         *cancellable)
 522 {
 523   GSource *base_source, *pollable_source;
 524
 525   base_source = g_timeout_source_new (0);
 526   pollable_source = g_pollable_source_new_full (stream, base_source,
 527                                                 cancellable);
 528   g_source_unref (base_source);
 529
 530   return pollable_source;
 531 }