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