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 "glibintl.h"
  30
  31 #include "gioalias.h"
  32
  33 /**
  34  * SECTION:gmemoryinputstream
  35  * @short_description: Streaming input operations on memory chunks
  36  * @include: 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   if (G_OBJECT_CLASS (g_memory_input_stream_parent_class)->finalize)
 167     (*G_OBJECT_CLASS (g_memory_input_stream_parent_class)->finalize) (object);
 168 }
 169
 170 static void
 171 g_memory_input_stream_seekable_iface_init (GSeekableIface *iface)
 172 {
 173   iface->tell         = g_memory_input_stream_tell;
 174   iface->can_seek     = g_memory_input_stream_can_seek;
 175   iface->seek         = g_memory_input_stream_seek;
 176   iface->can_truncate = g_memory_input_stream_can_truncate;
 177   iface->truncate_fn  = g_memory_input_stream_truncate;
 178 }
 179
 180 static void
 181 g_memory_input_stream_init (GMemoryInputStream *stream)
 182 {
 183   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 184                                               G_TYPE_MEMORY_INPUT_STREAM,
 185                                               GMemoryInputStreamPrivate);
 186 }
 187
 188 /**
 189  * g_memory_input_stream_new:
 190  *
 191  * Creates a new empty #GMemoryInputStream.
 192  *
 193  * Returns: a new #GInputStream
 194  */
 195 GInputStream *
 196 g_memory_input_stream_new (void)
 197 {
 198   GInputStream *stream;
 199
 200   stream = g_object_new (G_TYPE_MEMORY_INPUT_STREAM, NULL);
 201
 202   return stream;
 203 }
 204
 205 /**
 206  * g_memory_input_stream_new_from_data:
 207  * @data: input data
 208  * @len: length of the data, may be -1 if @data is a nul-terminated string
 209  * @destroy: function that is called to free @data, or %NULL
 210  *
 211  * Creates a new #GMemoryInputStream with data in memory of a given size.
 212  *
 213  * Returns: new #GInputStream read from @data of @len bytes.
 214  **/
 215 GInputStream *
 216 g_memory_input_stream_new_from_data (const void     *data,
 217                                      gssize          len,
 218                                      GDestroyNotify  destroy)
 219 {
 220   GInputStream *stream;
 221
 222   stream = g_memory_input_stream_new ();
 223
 224   g_memory_input_stream_add_data (G_MEMORY_INPUT_STREAM (stream),
 225                                   data, len, destroy);
 226
 227   return stream;
 228 }
 229
 230 /**
 231  * g_memory_input_stream_add_data:
 232  * @stream: a #GMemoryInputStream
 233  * @data: input data
 234  * @len: length of the data, may be -1 if @data is a nul-terminated string
 235  * @destroy: function that is called to free @data, or %NULL
 236  *
 237  * Appends @data to data that can be read from the input stream
 238  */
 239 void
 240 g_memory_input_stream_add_data (GMemoryInputStream *stream,
 241                                 const void         *data,
 242                                 gssize              len,
 243                                 GDestroyNotify      destroy)
 244 {
 245   GMemoryInputStreamPrivate *priv;
 246   Chunk *chunk;
 247
 248   g_return_if_fail (G_IS_MEMORY_INPUT_STREAM (stream));
 249   g_return_if_fail (data != NULL);
 250
 251   priv = stream->priv;
 252
 253   if (len == -1)
 254     len = strlen (data);
 255
 256   chunk = g_slice_new (Chunk);
 257   chunk->data = (guint8 *)data;
 258   chunk->len = len;
 259   chunk->destroy = destroy;
 260
 261   priv->chunks = g_slist_append (priv->chunks, chunk);
 262   priv->len += chunk->len;
 263 }
 264
 265 static gssize
 266 g_memory_input_stream_read (GInputStream  *stream,
 267                             void          *buffer,
 268                             gsize          count,
 269                             GCancellable  *cancellable,
 270                             GError       **error)
 271 {
 272   GMemoryInputStream *memory_stream;
 273   GMemoryInputStreamPrivate *priv;
 274   GSList *l;
 275   Chunk *chunk;
 276   gsize offset, start, rest, size;
 277
 278   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 279   priv = memory_stream->priv;
 280
 281   count = MIN (count, priv->len - priv->pos);
 282
 283   offset = 0;
 284   for (l = priv->chunks; l; l = l->next)
 285     {
 286       chunk = (Chunk *)l->data;
 287
 288       if (offset + chunk->len > priv->pos)
 289         break;
 290
 291       offset += chunk->len;
 292     }
 293
 294   start = priv->pos - offset;
 295   rest = count;
 296
 297   for (; l && rest > 0; l = l->next)
 298     {
 299       chunk = (Chunk *)l->data;
 300       size = MIN (rest, chunk->len - start);
 301
 302       memcpy ((guint8 *)buffer + (count - rest), chunk->data + start, size);
 303       rest -= size;
 304
 305       start = 0;
 306     }
 307
 308   priv->pos += count;
 309
 310   return count;
 311 }
 312
 313 static gssize
 314 g_memory_input_stream_skip (GInputStream  *stream,
 315                             gsize          count,
 316                             GCancellable  *cancellable,
 317                             GError       **error)
 318 {
 319   GMemoryInputStream *memory_stream;
 320   GMemoryInputStreamPrivate *priv;
 321
 322   memory_stream = G_MEMORY_INPUT_STREAM (stream);
 323   priv = memory_stream->priv;
 324
 325   count = MIN (count, priv->len - priv->pos);
 326   priv->pos += count;
 327
 328   return count;
 329 }
 330
 331 static gboolean
 332 g_memory_input_stream_close (GInputStream  *stream,
 333                              GCancellable  *cancellable,
 334                              GError       **error)
 335 {
 336   return TRUE;
 337 }
 338
 339 static void
 340 g_memory_input_stream_read_async (GInputStream        *stream,
 341                                   void                *buffer,
 342                                   gsize                count,
 343                                   int                  io_priority,
 344                                   GCancellable        *cancellable,
 345                                   GAsyncReadyCallback  callback,
 346                                   gpointer             user_data)
 347 {
 348   GSimpleAsyncResult *simple;
 349   gssize nread;
 350
 351   nread = g_memory_input_stream_read (stream, buffer, count, cancellable, NULL);
 352   simple = g_simple_async_result_new (G_OBJECT (stream),
 353                                       callback,
 354                                       user_data,
 355                                       g_memory_input_stream_read_async);
 356   g_simple_async_result_set_op_res_gssize (simple, nread);
 357   g_simple_async_result_complete_in_idle (simple);
 358   g_object_unref (simple);
 359 }
 360
 361 static gssize
 362 g_memory_input_stream_read_finish (GInputStream  *stream,
 363                                    GAsyncResult  *result,
 364                                    GError       **error)
 365 {
 366   GSimpleAsyncResult *simple;
 367   gssize nread;
 368
 369   simple = G_SIMPLE_ASYNC_RESULT (result);
 370   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_memory_input_stream_read_async);
 371
 372   nread = g_simple_async_result_get_op_res_gssize (simple);
 373   return nread;
 374 }
 375
 376 static void
 377 g_memory_input_stream_skip_async (GInputStream        *stream,
 378                                   gsize                count,
 379                                   int                  io_priority,
 380                                   GCancellable        *cancellable,
 381                                   GAsyncReadyCallback  callback,
 382                                   gpointer             user_data)
 383 {
 384   GSimpleAsyncResult *simple;
 385   gssize nskipped;
 386
 387   nskipped = g_memory_input_stream_skip (stream, count, cancellable, NULL);
 388   simple = g_simple_async_result_new (G_OBJECT (stream),
 389                                       callback,
 390                                       user_data,
 391                                       g_memory_input_stream_skip_async);
 392   g_simple_async_result_set_op_res_gssize (simple, nskipped);
 393   g_simple_async_result_complete_in_idle (simple);
 394   g_object_unref (simple);
 395 }
 396
 397 static gssize
 398 g_memory_input_stream_skip_finish (GInputStream  *stream,
 399                                    GAsyncResult  *result,
 400                                    GError       **error)
 401 {
 402   GSimpleAsyncResult *simple;
 403   gssize nskipped;
 404
 405   simple = G_SIMPLE_ASYNC_RESULT (result);
 406   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_memory_input_stream_skip_async);
 407
 408   nskipped = g_simple_async_result_get_op_res_gssize (simple);
 409   return nskipped;
 410 }
 411
 412 static void
 413 g_memory_input_stream_close_async (GInputStream        *stream,
 414                                    int                  io_priority,
 415                                    GCancellable        *cancellable,
 416                                    GAsyncReadyCallback  callback,
 417                                    gpointer             user_data)
 418 {
 419   GSimpleAsyncResult *simple;
 420
 421   simple = g_simple_async_result_new (G_OBJECT (stream),
 422                                       callback,
 423                                       user_data,
 424                                       g_memory_input_stream_close_async);
 425   g_simple_async_result_complete_in_idle (simple);
 426   g_object_unref (simple);
 427 }
 428
 429 static gboolean
 430 g_memory_input_stream_close_finish (GInputStream  *stream,
 431                                     GAsyncResult  *result,
 432                                     GError       **error)
 433 {
 434   return TRUE;
 435 }
 436
 437 static goffset
 438 g_memory_input_stream_tell (GSeekable *seekable)
 439 {
 440   GMemoryInputStream *memory_stream;
 441   GMemoryInputStreamPrivate *priv;
 442
 443   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 444   priv = memory_stream->priv;
 445
 446   return priv->pos;
 447 }
 448
 449 static
 450 gboolean g_memory_input_stream_can_seek (GSeekable *seekable)
 451 {
 452   return TRUE;
 453 }
 454
 455 static gboolean
 456 g_memory_input_stream_seek (GSeekable     *seekable,
 457                             goffset        offset,
 458                             GSeekType      type,
 459                             GCancellable  *cancellable,
 460                             GError       **error)
 461 {
 462   GMemoryInputStream *memory_stream;
 463   GMemoryInputStreamPrivate *priv;
 464   goffset absolute;
 465
 466   memory_stream = G_MEMORY_INPUT_STREAM (seekable);
 467   priv = memory_stream->priv;
 468
 469   switch (type)
 470     {
 471     case G_SEEK_CUR:
 472       absolute = priv->pos + offset;
 473       break;
 474
 475     case G_SEEK_SET:
 476       absolute = offset;
 477       break;
 478
 479     case G_SEEK_END:
 480       absolute = priv->len + offset;
 481       break;
 482
 483     default:
 484       g_set_error (error,
 485                    G_IO_ERROR,
 486                    G_IO_ERROR_INVALID_ARGUMENT,
 487                    _("Invalid GSeekType supplied"));
 488
 489       return FALSE;
 490     }
 491
 492   if (absolute < 0 || absolute > priv->len)
 493     {
 494       g_set_error (error,
 495                    G_IO_ERROR,
 496                    G_IO_ERROR_INVALID_ARGUMENT,
 497                    _("Invalid seek request"));
 498       return FALSE;
 499     }
 500
 501   priv->pos = absolute;
 502
 503   return TRUE;
 504 }
 505
 506 static gboolean
 507 g_memory_input_stream_can_truncate (GSeekable *seekable)
 508 {
 509   return FALSE;
 510 }
 511
 512 static gboolean
 513 g_memory_input_stream_truncate (GSeekable     *seekable,
 514                                 goffset        offset,
 515                                 GCancellable  *cancellable,
 516                                 GError       **error)
 517 {
 518   g_set_error (error,
 519                G_IO_ERROR,
 520                G_IO_ERROR_NOT_SUPPORTED,
 521                _("Cannot truncate GMemoryInputStream"));
 522   return FALSE;
 523 }
 524
 525 #define __G_MEMORY_INPUT_STREAM_C__
 526 #include "gioaliasdef.c"