gio/gmemoryoutputstream.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 "gmemoryoutputstream.h"
  25 #include "goutputstream.h"
  26 #include "gseekable.h"
  27 #include "gsimpleasyncresult.h"
  28 #include "string.h"
  29 #include "glibintl.h"
  30
  31 #include "gioalias.h"
  32
  33 /**
  34  * SECTION:gmemoryoutputstream
  35  * @short_description: Streaming output operations on memory chunks
  36  * @include: gio.h
  37  * @see_also: #GMemoryInputStream
  38  *
  39  * #GMemoryOutputStream is a class for using arbitrary
  40  * memory chunks as output for GIO streaming output operations.
  41  *
  42  */
  43
  44 #define MIN_ARRAY_SIZE  16
  45
  46 struct _GMemoryOutputStreamPrivate {
  47
  48   gpointer       data;
  49   gsize          len;
  50
  51   goffset        pos;
  52
  53   GReallocFunc   realloc_fn;
  54   GDestroyNotify destroy;
  55 };
  56
  57 static void     g_memory_output_stream_finalize     (GObject      *object);
  58
  59 static gssize   g_memory_output_stream_write       (GOutputStream *stream,
  60                                                     const void    *buffer,
  61                                                     gsize          count,
  62                                                     GCancellable  *cancellable,
  63                                                     GError       **error);
  64
  65 static gboolean g_memory_output_stream_close       (GOutputStream  *stream,
  66                                                     GCancellable   *cancellable,
  67                                                     GError        **error);
  68
  69 static void     g_memory_output_stream_write_async  (GOutputStream        *stream,
  70                                                      const void           *buffer,
  71                                                      gsize                 count,
  72                                                      int                   io_priority,
  73                                                      GCancellable         *cancellable,
  74                                                      GAsyncReadyCallback   callback,
  75                                                      gpointer              data);
  76 static gssize   g_memory_output_stream_write_finish (GOutputStream        *stream,
  77                                                      GAsyncResult         *result,
  78                                                      GError              **error);
  79 static void     g_memory_output_stream_close_async  (GOutputStream        *stream,
  80                                                      int                   io_priority,
  81                                                      GCancellable         *cancellable,
  82                                                      GAsyncReadyCallback   callback,
  83                                                      gpointer              data);
  84 static gboolean g_memory_output_stream_close_finish (GOutputStream        *stream,
  85                                                      GAsyncResult         *result,
  86                                                      GError              **error);
  87
  88 static void     g_memory_output_stream_seekable_iface_init (GSeekableIface  *iface);
  89 static goffset  g_memory_output_stream_tell                (GSeekable       *seekable);
  90 static gboolean g_memory_output_stream_can_seek            (GSeekable       *seekable);
  91 static gboolean g_memory_output_stream_seek                (GSeekable       *seekable,
  92                                                            goffset          offset,
  93                                                            GSeekType        type,
  94                                                            GCancellable    *cancellable,
  95                                                            GError         **error);
  96 static gboolean g_memory_output_stream_can_truncate        (GSeekable       *seekable);
  97 static gboolean g_memory_output_stream_truncate            (GSeekable       *seekable,
  98                                                            goffset          offset,
  99                                                            GCancellable    *cancellable,
 100                                                            GError         **error);
 101
 102 G_DEFINE_TYPE_WITH_CODE (GMemoryOutputStream, g_memory_output_stream, G_TYPE_OUTPUT_STREAM,
 103                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
 104                                                 g_memory_output_stream_seekable_iface_init))
 105
 106
 107 static void
 108 g_memory_output_stream_class_init (GMemoryOutputStreamClass *klass)
 109 {
 110   GOutputStreamClass *ostream_class;
 111   GObjectClass *gobject_class;
 112
 113   g_type_class_add_private (klass, sizeof (GMemoryOutputStreamPrivate));
 114
 115   gobject_class = G_OBJECT_CLASS (klass);
 116   gobject_class->finalize = g_memory_output_stream_finalize;
 117
 118   ostream_class = G_OUTPUT_STREAM_CLASS (klass);
 119
 120   ostream_class->write_fn = g_memory_output_stream_write;
 121   ostream_class->close_fn = g_memory_output_stream_close;
 122   ostream_class->write_async  = g_memory_output_stream_write_async;
 123   ostream_class->write_finish = g_memory_output_stream_write_finish;
 124   ostream_class->close_async  = g_memory_output_stream_close_async;
 125   ostream_class->close_finish = g_memory_output_stream_close_finish;
 126 }
 127
 128 static void
 129 g_memory_output_stream_finalize (GObject *object)
 130 {
 131   GMemoryOutputStream        *stream;
 132   GMemoryOutputStreamPrivate *priv;
 133
 134   stream = G_MEMORY_OUTPUT_STREAM (object);
 135   priv = stream->priv;
 136
 137   if (priv->destroy)
 138     priv->destroy (priv->data);
 139
 140   if (G_OBJECT_CLASS (g_memory_output_stream_parent_class)->finalize)
 141     (*G_OBJECT_CLASS (g_memory_output_stream_parent_class)->finalize) (object);
 142 }
 143
 144 static void
 145 g_memory_output_stream_seekable_iface_init (GSeekableIface *iface)
 146 {
 147   iface->tell         = g_memory_output_stream_tell;
 148   iface->can_seek     = g_memory_output_stream_can_seek;
 149   iface->seek         = g_memory_output_stream_seek;
 150   iface->can_truncate = g_memory_output_stream_can_truncate;
 151   iface->truncate_fn  = g_memory_output_stream_truncate;
 152 }
 153
 154
 155 static void
 156 g_memory_output_stream_init (GMemoryOutputStream *stream)
 157 {
 158   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 159                                               G_TYPE_MEMORY_OUTPUT_STREAM,
 160                                               GMemoryOutputStreamPrivate);
 161 }
 162
 163 /**
 164  * g_memory_output_stream_new:
 165  * @data: pointer to a chunk of memory to use, or %NULL
 166  * @len: the size of @data
 167  * @realloc_fn: a function with realloc() semantics to be called when
 168  *     @data needs to be grown, or %NULL
 169  * @destroy: a function to be called on @data when the stream is finalized,
 170  *     or %NULL
 171  *
 172  * Creates a new #GMemoryOutputStream.
 173  *
 174  * If @data is non-%NULL, the stream  will use that for its internal storage.
 175  * If @realloc_fn is non-%NULL, it will be used for resizing the internal
 176  * storage when necessary. To construct a fixed-size output stream,
 177  * pass %NULL as @realloc_fn.
 178  * |[
 179  * /&ast; a stream that can grow &ast;/
 180  * stream = g_memory_output_stream_new (NULL, 0, realloc, free);
 181  *
 182  * /&ast; a fixed-size stream &ast;/
 183  * data = malloc (200);
 184  * stream2 = g_memory_output_stream_new (data, 200, NULL, free);
 185  * ]|
 186  *
 187  * Return value: A newly created #GMemoryOutputStream object.
 188  **/
 189 GOutputStream *
 190 g_memory_output_stream_new (gpointer       data,
 191                             gsize          len,
 192                             GReallocFunc   realloc_fn,
 193                             GDestroyNotify destroy)
 194 {
 195   GOutputStream *stream;
 196   GMemoryOutputStreamPrivate *priv;
 197
 198   stream = g_object_new (G_TYPE_MEMORY_OUTPUT_STREAM, NULL);
 199
 200   priv = G_MEMORY_OUTPUT_STREAM (stream)->priv;
 201
 202   priv->data = data;
 203   priv->len = len;
 204   priv->realloc_fn = realloc_fn;
 205   priv->destroy = destroy;
 206
 207   priv->pos = 0;
 208
 209   return stream;
 210 }
 211
 212 /**
 213  * g_memory_output_stream_get_data:
 214  * @ostream: a #GMemoryOutputStream
 215  *
 216  * Gets any loaded data from the @ostream.
 217  *
 218  * Note that the returned pointer may become invalid on the next
 219  * write or truncate operation on the stream.
 220  *
 221  * Returns: pointer to the stream's data
 222  **/
 223 gpointer
 224 g_memory_output_stream_get_data (GMemoryOutputStream *ostream)
 225 {
 226   g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), NULL);
 227
 228   return ostream->priv->data;
 229 }
 230
 231 /**
 232  * g_memory_output_stream_get_size:
 233  * @ostream: a #GMemoryOutputStream
 234  *
 235  * Gets the size of the loaded data from the @ostream.
 236  *
 237  * Note that the returned size may become invalid on the next
 238  * write or truncate operation on the stream.
 239  *
 240  * Returns: the size of the stream's data
 241  */
 242 gsize
 243 g_memory_output_stream_get_size (GMemoryOutputStream *ostream)
 244 {
 245   g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), 0);
 246
 247   return ostream->priv->len;
 248 }
 249
 250 static gboolean
 251 array_check_boundary (GMemoryOutputStream  *stream,
 252                       goffset               size,
 253                       GError              **error)
 254 {
 255   if (size > G_MAXUINT)
 256     {
 257       g_set_error (error,
 258                    G_IO_ERROR,
 259                    G_IO_ERROR_FAILED,
 260                    _("Reached maximum data array limit"));
 261
 262       return FALSE;
 263     }
 264
 265   return TRUE;
 266 }
 267
 268 static gboolean
 269 array_resize (GMemoryOutputStream  *ostream,
 270               gsize                 size,
 271               gboolean              allow_partial,
 272               GError              **error)
 273 {
 274   GMemoryOutputStreamPrivate *priv;
 275   gpointer data;
 276   gsize len;
 277
 278   priv = ostream->priv;
 279
 280   if (!array_check_boundary (ostream, size, error))
 281     return FALSE;
 282
 283   if (priv->len == size)
 284     return TRUE;
 285
 286   if (!priv->realloc_fn)
 287     {
 288       if (allow_partial &&
 289           priv->pos < priv->len)
 290         return TRUE; /* Short write */
 291
 292       g_set_error (error,
 293                    G_IO_ERROR,
 294                    G_IO_ERROR_NO_SPACE,
 295                    _("Memory output stream not resizable"));
 296       return FALSE;
 297     }
 298
 299   len = priv->len;
 300   data = priv->realloc_fn (priv->data, size);
 301
 302   if (!data)
 303     {
 304       if (allow_partial &&
 305           priv->pos < priv->len)
 306         return TRUE; /* Short write */
 307
 308       g_set_error (error,
 309                    G_IO_ERROR,
 310                    G_IO_ERROR_NO_SPACE,
 311                    _("Failed to resize memory output stream"));
 312       return FALSE;
 313     }
 314
 315   if (size > len)
 316     memset (data + len, 0, size - len);
 317
 318   priv->data = data;
 319   priv->len = size;
 320
 321   return TRUE;
 322 }
 323
 324 static gint
 325 g_nearest_pow (gint num)
 326 {
 327   gint n = 1;
 328
 329   while (n < num)
 330     n <<= 1;
 331
 332   return n;
 333 }
 334
 335 static gssize
 336 g_memory_output_stream_write (GOutputStream  *stream,
 337                               const void     *buffer,
 338                               gsize           count,
 339                               GCancellable   *cancellable,
 340                               GError        **error)
 341 {
 342   GMemoryOutputStream        *ostream;
 343   GMemoryOutputStreamPrivate *priv;
 344   guint8   *dest;
 345   gsize new_size;
 346
 347   ostream = G_MEMORY_OUTPUT_STREAM (stream);
 348   priv = ostream->priv;
 349
 350   if (count == 0)
 351     return 0;
 352
 353   if (priv->pos + count > priv->len)
 354     {
 355       /* At least enought to fit the write, rounded up
 356          for greater than linear growth */
 357       new_size = g_nearest_pow (priv->pos + count);
 358       new_size = MAX (new_size, MIN_ARRAY_SIZE);
 359
 360       if (!array_resize (ostream, new_size, TRUE, error))
 361         return -1;
 362     }
 363
 364   /* Make sure we handle short writes if the array_resize
 365      only added part of the required memory */
 366   count = MIN (count, priv->len - priv->pos);
 367
 368   dest = priv->data + priv->pos;
 369   memcpy (dest, buffer, count);
 370   priv->pos += count;
 371
 372   return count;
 373 }
 374
 375 static gboolean
 376 g_memory_output_stream_close (GOutputStream  *stream,
 377                               GCancellable   *cancellable,
 378                               GError        **error)
 379 {
 380   return TRUE;
 381 }
 382
 383 static void
 384 g_memory_output_stream_write_async (GOutputStream       *stream,
 385                                     const void          *buffer,
 386                                     gsize                count,
 387                                     int                  io_priority,
 388                                     GCancellable        *cancellable,
 389                                     GAsyncReadyCallback  callback,
 390                                     gpointer             data)
 391 {
 392   GSimpleAsyncResult *simple;
 393   gssize nwritten;
 394
 395   nwritten = g_memory_output_stream_write (stream,
 396                                            buffer,
 397                                            count,
 398                                            cancellable,
 399                                            NULL);
 400
 401
 402   simple = g_simple_async_result_new (G_OBJECT (stream),
 403                                       callback,
 404                                       data,
 405                                       g_memory_output_stream_write_async);
 406
 407   g_simple_async_result_set_op_res_gssize (simple, nwritten);
 408   g_simple_async_result_complete_in_idle (simple);
 409   g_object_unref (simple);
 410 }
 411
 412 static gssize
 413 g_memory_output_stream_write_finish (GOutputStream  *stream,
 414                                      GAsyncResult   *result,
 415                                      GError        **error)
 416 {
 417   GSimpleAsyncResult *simple;
 418   gssize nwritten;
 419
 420   simple = G_SIMPLE_ASYNC_RESULT (result);
 421
 422   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) ==
 423                   g_memory_output_stream_write_async);
 424
 425   nwritten = g_simple_async_result_get_op_res_gssize (simple);
 426
 427   return nwritten;
 428 }
 429
 430 static void
 431 g_memory_output_stream_close_async (GOutputStream       *stream,
 432                                     int                  io_priority,
 433                                     GCancellable        *cancellable,
 434                                     GAsyncReadyCallback  callback,
 435                                     gpointer             data)
 436 {
 437   GSimpleAsyncResult *simple;
 438
 439   simple = g_simple_async_result_new (G_OBJECT (stream),
 440                                       callback,
 441                                       data,
 442                                       g_memory_output_stream_close_async);
 443
 444
 445   /* will always return TRUE */
 446   g_memory_output_stream_close (stream, cancellable, NULL);
 447
 448   g_simple_async_result_complete_in_idle (simple);
 449   g_object_unref (simple);
 450 }
 451
 452 static gboolean
 453 g_memory_output_stream_close_finish (GOutputStream  *stream,
 454                                      GAsyncResult   *result,
 455                                      GError        **error)
 456 {
 457   GSimpleAsyncResult *simple;
 458
 459   simple = G_SIMPLE_ASYNC_RESULT (result);
 460
 461   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) ==
 462                   g_memory_output_stream_close_async);
 463
 464   return TRUE;
 465 }
 466
 467 static goffset
 468 g_memory_output_stream_tell (GSeekable *seekable)
 469 {
 470   GMemoryOutputStream *stream;
 471   GMemoryOutputStreamPrivate *priv;
 472
 473   stream = G_MEMORY_OUTPUT_STREAM (seekable);
 474   priv = stream->priv;
 475
 476   return priv->pos;
 477 }
 478
 479 static gboolean
 480 g_memory_output_stream_can_seek (GSeekable *seekable)
 481 {
 482   return TRUE;
 483 }
 484
 485 static gboolean
 486 g_memory_output_stream_seek (GSeekable    *seekable,
 487                             goffset        offset,
 488                             GSeekType      type,
 489                             GCancellable  *cancellable,
 490                             GError       **error)
 491 {
 492   GMemoryOutputStream        *stream;
 493   GMemoryOutputStreamPrivate *priv;
 494   goffset absolute;
 495
 496   stream = G_MEMORY_OUTPUT_STREAM (seekable);
 497   priv = stream->priv;
 498
 499   switch (type)
 500     {
 501     case G_SEEK_CUR:
 502       absolute = priv->pos + offset;
 503       break;
 504
 505     case G_SEEK_SET:
 506       absolute = offset;
 507       break;
 508
 509     case G_SEEK_END:
 510       absolute = priv->len + offset;
 511       break;
 512
 513     default:
 514       g_set_error (error,
 515                    G_IO_ERROR,
 516                    G_IO_ERROR_INVALID_ARGUMENT,
 517                    _("Invalid GSeekType supplied"));
 518
 519       return FALSE;
 520     }
 521
 522   if (absolute < 0)
 523     {
 524       g_set_error (error,
 525                    G_IO_ERROR,
 526                    G_IO_ERROR_INVALID_ARGUMENT,
 527                    _("Invalid seek request"));
 528       return FALSE;
 529     }
 530
 531   if (!array_check_boundary (stream, absolute, error))
 532     return FALSE;
 533
 534   priv->pos = absolute;
 535
 536   return TRUE;
 537 }
 538
 539 static gboolean
 540 g_memory_output_stream_can_truncate (GSeekable *seekable)
 541 {
 542   GMemoryOutputStream *ostream;
 543   GMemoryOutputStreamPrivate *priv;
 544
 545   ostream = G_MEMORY_OUTPUT_STREAM (seekable);
 546   priv = ostream->priv;
 547
 548   return priv->realloc_fn != NULL;
 549 }
 550
 551 static gboolean
 552 g_memory_output_stream_truncate (GSeekable     *seekable,
 553                                  goffset        offset,
 554                                  GCancellable  *cancellable,
 555                                  GError       **error)
 556 {
 557   GMemoryOutputStream *ostream;
 558   GMemoryOutputStreamPrivate *priv;
 559
 560   ostream = G_MEMORY_OUTPUT_STREAM (seekable);
 561   priv = ostream->priv;
 562
 563   if (!array_resize (ostream, offset, FALSE, error))
 564     return FALSE;
 565
 566   return TRUE;
 567 }
 568
 569 #define __G_MEMORY_OUTPUT_STREAM_C__
 570 #include "gioaliasdef.c"