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 "gioerror.h"
  29 #include "string.h"
  30 #include "glibintl.h"
  31
  32 #include "gioalias.h"
  33
  34 /**
  35  * SECTION:gmemoryoutputstream
  36  * @short_description: Streaming output operations on memory chunks
  37  * @include: gio/gio.h
  38  * @see_also: #GMemoryInputStream
  39  *
  40  * #GMemoryOutputStream is a class for using arbitrary
  41  * memory chunks as output for GIO streaming output operations.
  42  *
  43  */
  44
  45 #define MIN_ARRAY_SIZE  16
  46
  47 struct _GMemoryOutputStreamPrivate {
  48
  49   gpointer       data;
  50   gsize          len;
  51   gsize          valid_len; /* The part of data that has been written to */
  52
  53   goffset        pos;
  54
  55   GReallocFunc   realloc_fn;
  56   GDestroyNotify destroy;
  57 };
  58
  59 static void     g_memory_output_stream_finalize     (GObject      *object);
  60
  61 static gssize   g_memory_output_stream_write       (GOutputStream *stream,
  62                                                     const void    *buffer,
  63                                                     gsize          count,
  64                                                     GCancellable  *cancellable,
  65                                                     GError       **error);
  66
  67 static gboolean g_memory_output_stream_close       (GOutputStream  *stream,
  68                                                     GCancellable   *cancellable,
  69                                                     GError        **error);
  70
  71 static void     g_memory_output_stream_write_async  (GOutputStream        *stream,
  72                                                      const void           *buffer,
  73                                                      gsize                 count,
  74                                                      int                   io_priority,
  75                                                      GCancellable         *cancellable,
  76                                                      GAsyncReadyCallback   callback,
  77                                                      gpointer              data);
  78 static gssize   g_memory_output_stream_write_finish (GOutputStream        *stream,
  79                                                      GAsyncResult         *result,
  80                                                      GError              **error);
  81 static void     g_memory_output_stream_close_async  (GOutputStream        *stream,
  82                                                      int                   io_priority,
  83                                                      GCancellable         *cancellable,
  84                                                      GAsyncReadyCallback   callback,
  85                                                      gpointer              data);
  86 static gboolean g_memory_output_stream_close_finish (GOutputStream        *stream,
  87                                                      GAsyncResult         *result,
  88                                                      GError              **error);
  89
  90 static void     g_memory_output_stream_seekable_iface_init (GSeekableIface  *iface);
  91 static goffset  g_memory_output_stream_tell                (GSeekable       *seekable);
  92 static gboolean g_memory_output_stream_can_seek            (GSeekable       *seekable);
  93 static gboolean g_memory_output_stream_seek                (GSeekable       *seekable,
  94                                                            goffset          offset,
  95                                                            GSeekType        type,
  96                                                            GCancellable    *cancellable,
  97                                                            GError         **error);
  98 static gboolean g_memory_output_stream_can_truncate        (GSeekable       *seekable);
  99 static gboolean g_memory_output_stream_truncate            (GSeekable       *seekable,
 100                                                            goffset          offset,
 101                                                            GCancellable    *cancellable,
 102                                                            GError         **error);
 103
 104 G_DEFINE_TYPE_WITH_CODE (GMemoryOutputStream, g_memory_output_stream, G_TYPE_OUTPUT_STREAM,
 105                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
 106                                                 g_memory_output_stream_seekable_iface_init))
 107
 108
 109 static void
 110 g_memory_output_stream_class_init (GMemoryOutputStreamClass *klass)
 111 {
 112   GOutputStreamClass *ostream_class;
 113   GObjectClass *gobject_class;
 114
 115   g_type_class_add_private (klass, sizeof (GMemoryOutputStreamPrivate));
 116
 117   gobject_class = G_OBJECT_CLASS (klass);
 118   gobject_class->finalize = g_memory_output_stream_finalize;
 119
 120   ostream_class = G_OUTPUT_STREAM_CLASS (klass);
 121
 122   ostream_class->write_fn = g_memory_output_stream_write;
 123   ostream_class->close_fn = g_memory_output_stream_close;
 124   ostream_class->write_async  = g_memory_output_stream_write_async;
 125   ostream_class->write_finish = g_memory_output_stream_write_finish;
 126   ostream_class->close_async  = g_memory_output_stream_close_async;
 127   ostream_class->close_finish = g_memory_output_stream_close_finish;
 128 }
 129
 130 static void
 131 g_memory_output_stream_finalize (GObject *object)
 132 {
 133   GMemoryOutputStream        *stream;
 134   GMemoryOutputStreamPrivate *priv;
 135
 136   stream = G_MEMORY_OUTPUT_STREAM (object);
 137   priv = stream->priv;
 138
 139   if (priv->destroy)
 140     priv->destroy (priv->data);
 141
 142   G_OBJECT_CLASS (g_memory_output_stream_parent_class)->finalize (object);
 143 }
 144
 145 static void
 146 g_memory_output_stream_seekable_iface_init (GSeekableIface *iface)
 147 {
 148   iface->tell         = g_memory_output_stream_tell;
 149   iface->can_seek     = g_memory_output_stream_can_seek;
 150   iface->seek         = g_memory_output_stream_seek;
 151   iface->can_truncate = g_memory_output_stream_can_truncate;
 152   iface->truncate_fn  = g_memory_output_stream_truncate;
 153 }
 154
 155
 156 static void
 157 g_memory_output_stream_init (GMemoryOutputStream *stream)
 158 {
 159   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 160                                               G_TYPE_MEMORY_OUTPUT_STREAM,
 161                                               GMemoryOutputStreamPrivate);
 162 }
 163
 164 /**
 165  * g_memory_output_stream_new:
 166  * @data: pointer to a chunk of memory to use, or %NULL
 167  * @len: the size of @data
 168  * @realloc_fn: a function with realloc() semantics to be called when
 169  *     @data needs to be grown, or %NULL
 170  * @destroy: a function to be called on @data when the stream is finalized,
 171  *     or %NULL
 172  *
 173  * Creates a new #GMemoryOutputStream.
 174  *
 175  * If @data is non-%NULL, the stream  will use that for its internal storage.
 176  * If @realloc_fn is non-%NULL, it will be used for resizing the internal
 177  * storage when necessary. To construct a fixed-size output stream,
 178  * pass %NULL as @realloc_fn.
 179  * |[
 180  * /&ast; a stream that can grow &ast;/
 181  * stream = g_memory_output_stream_new (NULL, 0, realloc, free);
 182  *
 183  * /&ast; a fixed-size stream &ast;/
 184  * data = malloc (200);
 185  * stream2 = g_memory_output_stream_new (data, 200, NULL, free);
 186  * ]|
 187  *
 188  * Return value: A newly created #GMemoryOutputStream object.
 189  **/
 190 GOutputStream *
 191 g_memory_output_stream_new (gpointer       data,
 192                             gsize          len,
 193                             GReallocFunc   realloc_fn,
 194                             GDestroyNotify destroy)
 195 {
 196   GOutputStream *stream;
 197   GMemoryOutputStreamPrivate *priv;
 198
 199   stream = g_object_new (G_TYPE_MEMORY_OUTPUT_STREAM, NULL);
 200
 201   priv = G_MEMORY_OUTPUT_STREAM (stream)->priv;
 202
 203   priv->data = data;
 204   priv->len = len;
 205   priv->realloc_fn = realloc_fn;
 206   priv->destroy = destroy;
 207
 208   priv->pos = 0;
 209   priv->valid_len = 0;
 210
 211   return stream;
 212 }
 213
 214 /**
 215  * g_memory_output_stream_get_data:
 216  * @ostream: a #GMemoryOutputStream
 217  *
 218  * Gets any loaded data from the @ostream.
 219  *
 220  * Note that the returned pointer may become invalid on the next
 221  * write or truncate operation on the stream.
 222  *
 223  * Returns: pointer to the stream's data
 224  **/
 225 gpointer
 226 g_memory_output_stream_get_data (GMemoryOutputStream *ostream)
 227 {
 228   g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), NULL);
 229
 230   return ostream->priv->data;
 231 }
 232
 233 /**
 234  * g_memory_output_stream_get_size:
 235  * @ostream: a #GMemoryOutputStream
 236  *
 237  * Gets the size of the currently allocated data area (availible from
 238  * g_memory_output_stream_get_data()). If the stream isn't
 239  * growable (no realloc was passed to g_memory_output_stream_new()) then
 240  * this is the maximum size of the stream and further writes
 241  * will return %G_IO_ERROR_NO_SPACE.
 242  *
 243  * Note that for growable streams the returned size may become invalid on
 244  * the next write or truncate operation on the stream.
 245  *
 246  * If you want the number of bytes currently written to the stream, use
 247  * g_memory_output_stream_get_data_size().
 248  *
 249  * Returns: the number of bytes allocated for the data buffer
 250  */
 251 gsize
 252 g_memory_output_stream_get_size (GMemoryOutputStream *ostream)
 253 {
 254   g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), 0);
 255
 256   return ostream->priv->len;
 257 }
 258
 259 /**
 260  * g_memory_output_stream_get_data_size:
 261  * @ostream: a #GMemoryOutputStream
 262  *
 263  * Returns the number of bytes from the start up
 264  * to including the last byte written in the stream
 265  * that has not been truncated away.
 266  *
 267  * Returns: the number of bytes written to the stream
 268  *
 269  * Since: 2.18
 270  */
 271 gsize
 272 g_memory_output_stream_get_data_size (GMemoryOutputStream *ostream)
 273 {
 274   g_return_val_if_fail (G_IS_MEMORY_OUTPUT_STREAM (ostream), 0);
 275
 276   return ostream->priv->valid_len;
 277 }
 278
 279
 280 static gboolean
 281 array_check_boundary (GMemoryOutputStream  *stream,
 282                       goffset               size,
 283                       GError              **error)
 284 {
 285   if (size > G_MAXUINT)
 286     {
 287       g_set_error_literal (error,
 288                            G_IO_ERROR,
 289                            G_IO_ERROR_FAILED,
 290                            _("Reached maximum data array limit"));
 291
 292       return FALSE;
 293     }
 294
 295   return TRUE;
 296 }
 297
 298 static gboolean
 299 array_resize (GMemoryOutputStream  *ostream,
 300               gsize                 size,
 301               gboolean              allow_partial,
 302               GError              **error)
 303 {
 304   GMemoryOutputStreamPrivate *priv;
 305   gpointer data;
 306   gsize len;
 307
 308   priv = ostream->priv;
 309
 310   if (!array_check_boundary (ostream, size, error))
 311     return FALSE;
 312
 313   if (priv->len == size)
 314     return TRUE;
 315
 316   if (!priv->realloc_fn)
 317     {
 318       if (allow_partial &&
 319           priv->pos < priv->len)
 320         return TRUE; /* Short write */
 321
 322       g_set_error_literal (error,
 323                            G_IO_ERROR,
 324                            G_IO_ERROR_NO_SPACE,
 325                            _("Memory output stream not resizable"));
 326       return FALSE;
 327     }
 328
 329   len = priv->len;
 330   data = priv->realloc_fn (priv->data, size);
 331
 332   if (size > 0 && !data)
 333     {
 334       if (allow_partial &&
 335           priv->pos < priv->len)
 336         return TRUE; /* Short write */
 337
 338       g_set_error_literal (error,
 339                            G_IO_ERROR,
 340                            G_IO_ERROR_NO_SPACE,
 341                            _("Failed to resize memory output stream"));
 342       return FALSE;
 343     }
 344
 345   if (size > len)
 346     memset ((guint8 *)data + len, 0, size - len);
 347
 348   priv->data = data;
 349   priv->len = size;
 350
 351   if (priv->len < priv->valid_len)
 352     priv->valid_len = priv->len;
 353
 354   return TRUE;
 355 }
 356
 357 static gint
 358 g_nearest_pow (gint num)
 359 {
 360   gint n = 1;
 361
 362   while (n < num)
 363     n <<= 1;
 364
 365   return n;
 366 }
 367
 368 static gssize
 369 g_memory_output_stream_write (GOutputStream  *stream,
 370                               const void     *buffer,
 371                               gsize           count,
 372                               GCancellable   *cancellable,
 373                               GError        **error)
 374 {
 375   GMemoryOutputStream        *ostream;
 376   GMemoryOutputStreamPrivate *priv;
 377   guint8   *dest;
 378   gsize new_size;
 379
 380   ostream = G_MEMORY_OUTPUT_STREAM (stream);
 381   priv = ostream->priv;
 382
 383   if (count == 0)
 384     return 0;
 385
 386   if (priv->pos + count > priv->len)
 387     {
 388       /* At least enought to fit the write, rounded up
 389          for greater than linear growth */
 390       new_size = g_nearest_pow (priv->pos + count);
 391       new_size = MAX (new_size, MIN_ARRAY_SIZE);
 392
 393       if (!array_resize (ostream, new_size, TRUE, error))
 394         return -1;
 395     }
 396
 397   /* Make sure we handle short writes if the array_resize
 398      only added part of the required memory */
 399   count = MIN (count, priv->len - priv->pos);
 400
 401   dest = (guint8 *)priv->data + priv->pos;
 402   memcpy (dest, buffer, count);
 403   priv->pos += count;
 404
 405   if (priv->pos > priv->valid_len)
 406     priv->valid_len = priv->pos;
 407
 408   return count;
 409 }
 410
 411 static gboolean
 412 g_memory_output_stream_close (GOutputStream  *stream,
 413                               GCancellable   *cancellable,
 414                               GError        **error)
 415 {
 416   return TRUE;
 417 }
 418
 419 static void
 420 g_memory_output_stream_write_async (GOutputStream       *stream,
 421                                     const void          *buffer,
 422                                     gsize                count,
 423                                     int                  io_priority,
 424                                     GCancellable        *cancellable,
 425                                     GAsyncReadyCallback  callback,
 426                                     gpointer             data)
 427 {
 428   GSimpleAsyncResult *simple;
 429   gssize nwritten;
 430
 431   nwritten = g_memory_output_stream_write (stream,
 432                                            buffer,
 433                                            count,
 434                                            cancellable,
 435                                            NULL);
 436
 437
 438   simple = g_simple_async_result_new (G_OBJECT (stream),
 439                                       callback,
 440                                       data,
 441                                       g_memory_output_stream_write_async);
 442
 443   g_simple_async_result_set_op_res_gssize (simple, nwritten);
 444   g_simple_async_result_complete_in_idle (simple);
 445   g_object_unref (simple);
 446 }
 447
 448 static gssize
 449 g_memory_output_stream_write_finish (GOutputStream  *stream,
 450                                      GAsyncResult   *result,
 451                                      GError        **error)
 452 {
 453   GSimpleAsyncResult *simple;
 454   gssize nwritten;
 455
 456   simple = G_SIMPLE_ASYNC_RESULT (result);
 457
 458   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) ==
 459                   g_memory_output_stream_write_async);
 460
 461   nwritten = g_simple_async_result_get_op_res_gssize (simple);
 462
 463   return nwritten;
 464 }
 465
 466 static void
 467 g_memory_output_stream_close_async (GOutputStream       *stream,
 468                                     int                  io_priority,
 469                                     GCancellable        *cancellable,
 470                                     GAsyncReadyCallback  callback,
 471                                     gpointer             data)
 472 {
 473   GSimpleAsyncResult *simple;
 474
 475   simple = g_simple_async_result_new (G_OBJECT (stream),
 476                                       callback,
 477                                       data,
 478                                       g_memory_output_stream_close_async);
 479
 480
 481   /* will always return TRUE */
 482   g_memory_output_stream_close (stream, cancellable, NULL);
 483
 484   g_simple_async_result_complete_in_idle (simple);
 485   g_object_unref (simple);
 486 }
 487
 488 static gboolean
 489 g_memory_output_stream_close_finish (GOutputStream  *stream,
 490                                      GAsyncResult   *result,
 491                                      GError        **error)
 492 {
 493   GSimpleAsyncResult *simple;
 494
 495   simple = G_SIMPLE_ASYNC_RESULT (result);
 496
 497   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) ==
 498                   g_memory_output_stream_close_async);
 499
 500   return TRUE;
 501 }
 502
 503 static goffset
 504 g_memory_output_stream_tell (GSeekable *seekable)
 505 {
 506   GMemoryOutputStream *stream;
 507   GMemoryOutputStreamPrivate *priv;
 508
 509   stream = G_MEMORY_OUTPUT_STREAM (seekable);
 510   priv = stream->priv;
 511
 512   return priv->pos;
 513 }
 514
 515 static gboolean
 516 g_memory_output_stream_can_seek (GSeekable *seekable)
 517 {
 518   return TRUE;
 519 }
 520
 521 static gboolean
 522 g_memory_output_stream_seek (GSeekable    *seekable,
 523                             goffset        offset,
 524                             GSeekType      type,
 525                             GCancellable  *cancellable,
 526                             GError       **error)
 527 {
 528   GMemoryOutputStream        *stream;
 529   GMemoryOutputStreamPrivate *priv;
 530   goffset absolute;
 531
 532   stream = G_MEMORY_OUTPUT_STREAM (seekable);
 533   priv = stream->priv;
 534
 535   switch (type)
 536     {
 537     case G_SEEK_CUR:
 538       absolute = priv->pos + offset;
 539       break;
 540
 541     case G_SEEK_SET:
 542       absolute = offset;
 543       break;
 544
 545     case G_SEEK_END:
 546       absolute = priv->len + offset;
 547       break;
 548
 549     default:
 550       g_set_error_literal (error,
 551                            G_IO_ERROR,
 552                            G_IO_ERROR_INVALID_ARGUMENT,
 553                            _("Invalid GSeekType supplied"));
 554
 555       return FALSE;
 556     }
 557
 558   if (absolute < 0)
 559     {
 560       g_set_error_literal (error,
 561                            G_IO_ERROR,
 562                            G_IO_ERROR_INVALID_ARGUMENT,
 563                            _("Invalid seek request"));
 564       return FALSE;
 565     }
 566
 567   if (!array_check_boundary (stream, absolute, error))
 568     return FALSE;
 569
 570   priv->pos = absolute;
 571
 572   return TRUE;
 573 }
 574
 575 static gboolean
 576 g_memory_output_stream_can_truncate (GSeekable *seekable)
 577 {
 578   GMemoryOutputStream *ostream;
 579   GMemoryOutputStreamPrivate *priv;
 580
 581   ostream = G_MEMORY_OUTPUT_STREAM (seekable);
 582   priv = ostream->priv;
 583
 584   return priv->realloc_fn != NULL;
 585 }
 586
 587 static gboolean
 588 g_memory_output_stream_truncate (GSeekable     *seekable,
 589                                  goffset        offset,
 590                                  GCancellable  *cancellable,
 591                                  GError       **error)
 592 {
 593   GMemoryOutputStream *ostream;
 594   GMemoryOutputStreamPrivate *priv;
 595
 596   ostream = G_MEMORY_OUTPUT_STREAM (seekable);
 597   priv = ostream->priv;
 598
 599   if (!array_resize (ostream, offset, FALSE, error))
 600     return FALSE;
 601
 602   return TRUE;
 603 }
 604
 605 #define __G_MEMORY_OUTPUT_STREAM_C__
 606 #include "gioaliasdef.c"