gio/gbufferedinputstream.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  * Copyright (C) 2007 Jürg Billeter
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General
  17  * Public License along with this library; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  19  * Boston, MA 02111-1307, USA.
  20  *
  21  * Author: Christian Kellner <gicmo@gnome.org>
  22  */
  23
  24 #include "config.h"
  25 #include "gbufferedinputstream.h"
  26 #include "ginputstream.h"
  27 #include "gcancellable.h"
  28 #include "gasyncresult.h"
  29 #include "gsimpleasyncresult.h"
  30 #include "gseekable.h"
  31 #include "gioerror.h"
  32 #include <string.h>
  33 #include "glibintl.h"
  34
  35
  36 /**
  37  * SECTION:gbufferedinputstream
  38  * @short_description: Buffered Input Stream
  39  * @include: gio/gio.h
  40  * @see_also: #GFilterInputStream, #GInputStream
  41  *
  42  * Buffered input stream implements #GFilterInputStream and provides
  43  * for buffered reads.
  44  *
  45  * By default, #GBufferedInputStream's buffer size is set at 4 kilobytes.
  46  *
  47  * To create a buffered input stream, use g_buffered_input_stream_new(),
  48  * or g_buffered_input_stream_new_sized() to specify the buffer's size at
  49  * construction.
  50  *
  51  * To get the size of a buffer within a buffered input stream, use
  52  * g_buffered_input_stream_get_buffer_size(). To change the size of a
  53  * buffered input stream's buffer, use
  54  * g_buffered_input_stream_set_buffer_size(). Note that the buffer's size
  55  * cannot be reduced below the size of the data within the buffer.
  56  */
  57
  58
  59 #define DEFAULT_BUFFER_SIZE 4096
  60
  61 struct _GBufferedInputStreamPrivate {
  62   guint8 *buffer;
  63   gsize   len;
  64   gsize   pos;
  65   gsize   end;
  66   GAsyncReadyCallback outstanding_callback;
  67 };
  68
  69 enum {
  70   PROP_0,
  71   PROP_BUFSIZE
  72 };
  73
  74 static void g_buffered_input_stream_set_property  (GObject      *object,
  75                                                    guint         prop_id,
  76                                                    const GValue *value,
  77                                                    GParamSpec   *pspec);
  78
  79 static void g_buffered_input_stream_get_property  (GObject      *object,
  80                                                    guint         prop_id,
  81                                                    GValue       *value,
  82                                                    GParamSpec   *pspec);
  83 static void g_buffered_input_stream_finalize      (GObject *object);
  84
  85
  86 static gssize g_buffered_input_stream_skip             (GInputStream          *stream,
  87                                                         gsize                  count,
  88                                                         GCancellable          *cancellable,
  89                                                         GError               **error);
  90 static void   g_buffered_input_stream_skip_async       (GInputStream          *stream,
  91                                                         gsize                  count,
  92                                                         int                    io_priority,
  93                                                         GCancellable          *cancellable,
  94                                                         GAsyncReadyCallback    callback,
  95                                                         gpointer               user_data);
  96 static gssize g_buffered_input_stream_skip_finish      (GInputStream          *stream,
  97                                                         GAsyncResult          *result,
  98                                                         GError               **error);
  99 static gssize g_buffered_input_stream_read             (GInputStream          *stream,
 100                                                         void                  *buffer,
 101                                                         gsize                  count,
 102                                                         GCancellable          *cancellable,
 103                                                         GError               **error);
 104 static gssize g_buffered_input_stream_real_fill        (GBufferedInputStream  *stream,
 105                                                         gssize                 count,
 106                                                         GCancellable          *cancellable,
 107                                                         GError               **error);
 108 static void   g_buffered_input_stream_real_fill_async  (GBufferedInputStream  *stream,
 109                                                         gssize                 count,
 110                                                         int                    io_priority,
 111                                                         GCancellable          *cancellable,
 112                                                         GAsyncReadyCallback    callback,
 113                                                         gpointer               user_data);
 114 static gssize g_buffered_input_stream_real_fill_finish (GBufferedInputStream  *stream,
 115                                                         GAsyncResult          *result,
 116                                                         GError               **error);
 117
 118 static void     g_buffered_input_stream_seekable_iface_init (GSeekableIface  *iface);
 119 static goffset  g_buffered_input_stream_tell                (GSeekable       *seekable);
 120 static gboolean g_buffered_input_stream_can_seek            (GSeekable       *seekable);
 121 static gboolean g_buffered_input_stream_seek                (GSeekable       *seekable,
 122                                                              goffset          offset,
 123                                                              GSeekType        type,
 124                                                              GCancellable    *cancellable,
 125                                                              GError         **error);
 126 static gboolean g_buffered_input_stream_can_truncate        (GSeekable       *seekable);
 127 static gboolean g_buffered_input_stream_truncate            (GSeekable       *seekable,
 128                                                              goffset          offset,
 129                                                              GCancellable    *cancellable,
 130                                                              GError         **error);
 131
 132 static void     g_buffered_input_stream_finalize            (GObject         *object);
 133
 134 static void compact_buffer (GBufferedInputStream *stream);
 135
 136 G_DEFINE_TYPE_WITH_CODE (GBufferedInputStream,
 137                          g_buffered_input_stream,
 138                          G_TYPE_FILTER_INPUT_STREAM,
 139                          G_IMPLEMENT_INTERFACE (G_TYPE_SEEKABLE,
 140                                                 g_buffered_input_stream_seekable_iface_init))
 141
 142 static void
 143 g_buffered_input_stream_class_init (GBufferedInputStreamClass *klass)
 144 {
 145   GObjectClass *object_class;
 146   GInputStreamClass *istream_class;
 147   GBufferedInputStreamClass *bstream_class;
 148
 149   g_type_class_add_private (klass, sizeof (GBufferedInputStreamPrivate));
 150
 151   object_class = G_OBJECT_CLASS (klass);
 152   object_class->get_property = g_buffered_input_stream_get_property;
 153   object_class->set_property = g_buffered_input_stream_set_property;
 154   object_class->finalize     = g_buffered_input_stream_finalize;
 155
 156   istream_class = G_INPUT_STREAM_CLASS (klass);
 157   istream_class->skip = g_buffered_input_stream_skip;
 158   istream_class->skip_async  = g_buffered_input_stream_skip_async;
 159   istream_class->skip_finish = g_buffered_input_stream_skip_finish;
 160   istream_class->read_fn = g_buffered_input_stream_read;
 161
 162   bstream_class = G_BUFFERED_INPUT_STREAM_CLASS (klass);
 163   bstream_class->fill = g_buffered_input_stream_real_fill;
 164   bstream_class->fill_async = g_buffered_input_stream_real_fill_async;
 165   bstream_class->fill_finish = g_buffered_input_stream_real_fill_finish;
 166
 167   g_object_class_install_property (object_class,
 168                                    PROP_BUFSIZE,
 169                                    g_param_spec_uint ("buffer-size",
 170                                                       P_("Buffer Size"),
 171                                                       P_("The size of the backend buffer"),
 172                                                       1,
 173                                                       G_MAXUINT,
 174                                                       DEFAULT_BUFFER_SIZE,
 175                                                       G_PARAM_READWRITE | G_PARAM_CONSTRUCT |
 176                                                       G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
 177
 178
 179 }
 180
 181 /**
 182  * g_buffered_input_stream_get_buffer_size:
 183  * @stream: a #GBufferedInputStream
 184  *
 185  * Gets the size of the input buffer.
 186  *
 187  * Returns: the current buffer size.
 188  */
 189 gsize
 190 g_buffered_input_stream_get_buffer_size (GBufferedInputStream  *stream)
 191 {
 192   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), 0);
 193
 194   return stream->priv->len;
 195 }
 196
 197 /**
 198  * g_buffered_input_stream_set_buffer_size:
 199  * @stream: a #GBufferedInputStream
 200  * @size: a #gsize
 201  *
 202  * Sets the size of the internal buffer of @stream to @size, or to the
 203  * size of the contents of the buffer. The buffer can never be resized
 204  * smaller than its current contents.
 205  */
 206 void
 207 g_buffered_input_stream_set_buffer_size (GBufferedInputStream *stream,
 208                                          gsize                 size)
 209 {
 210   GBufferedInputStreamPrivate *priv;
 211   gsize in_buffer;
 212   guint8 *buffer;
 213
 214   g_return_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream));
 215
 216   priv = stream->priv;
 217
 218   if (priv->len == size)
 219     return;
 220
 221   if (priv->buffer)
 222     {
 223       in_buffer = priv->end - priv->pos;
 224
 225       /* Never resize smaller than current buffer contents */
 226       size = MAX (size, in_buffer);
 227
 228       buffer = g_malloc (size);
 229       memcpy (buffer, priv->buffer + priv->pos, in_buffer);
 230       priv->len = size;
 231       priv->pos = 0;
 232       priv->end = in_buffer;
 233       g_free (priv->buffer);
 234       priv->buffer = buffer;
 235     }
 236   else
 237     {
 238       priv->len = size;
 239       priv->pos = 0;
 240       priv->end = 0;
 241       priv->buffer = g_malloc (size);
 242     }
 243
 244   g_object_notify (G_OBJECT (stream), "buffer-size");
 245 }
 246
 247 static void
 248 g_buffered_input_stream_set_property (GObject      *object,
 249                                       guint         prop_id,
 250                                       const GValue *value,
 251                                       GParamSpec   *pspec)
 252 {
 253   GBufferedInputStream        *bstream;
 254
 255   bstream = G_BUFFERED_INPUT_STREAM (object);
 256
 257   switch (prop_id)
 258     {
 259     case PROP_BUFSIZE:
 260       g_buffered_input_stream_set_buffer_size (bstream, g_value_get_uint (value));
 261       break;
 262
 263     default:
 264       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 265       break;
 266     }
 267 }
 268
 269 static void
 270 g_buffered_input_stream_get_property (GObject    *object,
 271                                       guint       prop_id,
 272                                       GValue     *value,
 273                                       GParamSpec *pspec)
 274 {
 275   GBufferedInputStreamPrivate *priv;
 276   GBufferedInputStream        *bstream;
 277
 278   bstream = G_BUFFERED_INPUT_STREAM (object);
 279   priv = bstream->priv;
 280
 281   switch (prop_id)
 282     {
 283     case PROP_BUFSIZE:
 284       g_value_set_uint (value, priv->len);
 285       break;
 286
 287     default:
 288       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 289       break;
 290     }
 291 }
 292
 293 static void
 294 g_buffered_input_stream_finalize (GObject *object)
 295 {
 296   GBufferedInputStreamPrivate *priv;
 297   GBufferedInputStream        *stream;
 298
 299   stream = G_BUFFERED_INPUT_STREAM (object);
 300   priv = stream->priv;
 301
 302   g_free (priv->buffer);
 303
 304   G_OBJECT_CLASS (g_buffered_input_stream_parent_class)->finalize (object);
 305 }
 306
 307 static void
 308 g_buffered_input_stream_seekable_iface_init (GSeekableIface *iface)
 309 {
 310   iface->tell         = g_buffered_input_stream_tell;
 311   iface->can_seek     = g_buffered_input_stream_can_seek;
 312   iface->seek         = g_buffered_input_stream_seek;
 313   iface->can_truncate = g_buffered_input_stream_can_truncate;
 314   iface->truncate_fn  = g_buffered_input_stream_truncate;
 315 }
 316
 317 static void
 318 g_buffered_input_stream_init (GBufferedInputStream *stream)
 319 {
 320   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 321                                               G_TYPE_BUFFERED_INPUT_STREAM,
 322                                               GBufferedInputStreamPrivate);
 323 }
 324
 325
 326 /**
 327  * g_buffered_input_stream_new:
 328  * @base_stream: a #GInputStream
 329  *
 330  * Creates a new #GInputStream from the given @base_stream, with
 331  * a buffer set to the default size (4 kilobytes).
 332  *
 333  * Returns: a #GInputStream for the given @base_stream.
 334  */
 335 GInputStream *
 336 g_buffered_input_stream_new (GInputStream *base_stream)
 337 {
 338   GInputStream *stream;
 339
 340   g_return_val_if_fail (G_IS_INPUT_STREAM (base_stream), NULL);
 341
 342   stream = g_object_new (G_TYPE_BUFFERED_INPUT_STREAM,
 343                          "base-stream", base_stream,
 344                          NULL);
 345
 346   return stream;
 347 }
 348
 349 /**
 350  * g_buffered_input_stream_new_sized:
 351  * @base_stream: a #GInputStream
 352  * @size: a #gsize
 353  *
 354  * Creates a new #GBufferedInputStream from the given @base_stream,
 355  * with a buffer set to @size.
 356  *
 357  * Returns: a #GInputStream.
 358  */
 359 GInputStream *
 360 g_buffered_input_stream_new_sized (GInputStream *base_stream,
 361                                    gsize         size)
 362 {
 363   GInputStream *stream;
 364
 365   g_return_val_if_fail (G_IS_INPUT_STREAM (base_stream), NULL);
 366
 367   stream = g_object_new (G_TYPE_BUFFERED_INPUT_STREAM,
 368                          "base-stream", base_stream,
 369                          "buffer-size", (guint)size,
 370                          NULL);
 371
 372   return stream;
 373 }
 374
 375 /**
 376  * g_buffered_input_stream_fill:
 377  * @stream: a #GBufferedInputStream
 378  * @count: the number of bytes that will be read from the stream
 379  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 380  * @error: location to store the error occurring, or %NULL to ignore
 381  *
 382  * Tries to read @count bytes from the stream into the buffer.
 383  * Will block during this read.
 384  *
 385  * If @count is zero, returns zero and does nothing. A value of @count
 386  * larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.
 387  *
 388  * On success, the number of bytes read into the buffer is returned.
 389  * It is not an error if this is not the same as the requested size, as it
 390  * can happen e.g. near the end of a file. Zero is returned on end of file
 391  * (or if @count is zero),  but never otherwise.
 392  *
 393  * If @count is -1 then the attempted read size is equal to the number of
 394  * bytes that are required to fill the buffer.
 395  *
 396  * If @cancellable is not %NULL, then the operation can be cancelled by
 397  * triggering the cancellable object from another thread. If the operation
 398  * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
 399  * operation was partially finished when the operation was cancelled the
 400  * partial result will be returned, without an error.
 401  *
 402  * On error -1 is returned and @error is set accordingly.
 403  *
 404  * For the asynchronous, non-blocking, version of this function, see
 405  * g_buffered_input_stream_fill_async().
 406  *
 407  * Returns: the number of bytes read into @stream's buffer, up to @count,
 408  *     or -1 on error.
 409  */
 410 gssize
 411 g_buffered_input_stream_fill (GBufferedInputStream  *stream,
 412                               gssize                 count,
 413                               GCancellable          *cancellable,
 414                               GError               **error)
 415 {
 416   GBufferedInputStreamClass *class;
 417   GInputStream *input_stream;
 418   gssize res;
 419
 420   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 421
 422   input_stream = G_INPUT_STREAM (stream);
 423
 424   if (count < -1)
 425     {
 426       g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
 427                    _("Too large count value passed to %s"), G_STRFUNC);
 428       return -1;
 429     }
 430
 431   if (!g_input_stream_set_pending (input_stream, error))
 432     return -1;
 433
 434   if (cancellable)
 435     g_cancellable_push_current (cancellable);
 436
 437   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 438   res = class->fill (stream, count, cancellable, error);
 439
 440   if (cancellable)
 441     g_cancellable_pop_current (cancellable);
 442
 443   g_input_stream_clear_pending (input_stream);
 444
 445   return res;
 446 }
 447
 448 static void
 449 async_fill_callback_wrapper (GObject      *source_object,
 450                              GAsyncResult *res,
 451                              gpointer      user_data)
 452 {
 453   GBufferedInputStream *stream = G_BUFFERED_INPUT_STREAM (source_object);
 454
 455   g_input_stream_clear_pending (G_INPUT_STREAM (stream));
 456   (*stream->priv->outstanding_callback) (source_object, res, user_data);
 457   g_object_unref (stream);
 458 }
 459
 460 /**
 461  * g_buffered_input_stream_fill_async:
 462  * @stream: a #GBufferedInputStream
 463  * @count: the number of bytes that will be read from the stream
 464  * @io_priority: the <link linkend="io-priority">I/O priority</link>
 465  *     of the request
 466  * @cancellable: (allow-none): optional #GCancellable object
 467  * @callback: (scope async): a #GAsyncReadyCallback
 468  * @user_data: (closure): a #gpointer
 469  *
 470  * Reads data into @stream's buffer asynchronously, up to @count size.
 471  * @io_priority can be used to prioritize reads. For the synchronous
 472  * version of this function, see g_buffered_input_stream_fill().
 473  *
 474  * If @count is -1 then the attempted read size is equal to the number
 475  * of bytes that are required to fill the buffer.
 476  */
 477 void
 478 g_buffered_input_stream_fill_async (GBufferedInputStream *stream,
 479                                     gssize                count,
 480                                     int                   io_priority,
 481                                     GCancellable         *cancellable,
 482                                     GAsyncReadyCallback   callback,
 483                                     gpointer              user_data)
 484 {
 485   GBufferedInputStreamClass *class;
 486   GSimpleAsyncResult *simple;
 487   GError *error = NULL;
 488
 489   g_return_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream));
 490
 491   if (count == 0)
 492     {
 493       simple = g_simple_async_result_new (G_OBJECT (stream),
 494                                           callback,
 495                                           user_data,
 496                                           g_buffered_input_stream_fill_async);
 497       g_simple_async_result_complete_in_idle (simple);
 498       g_object_unref (simple);
 499       return;
 500     }
 501
 502   if (count < -1)
 503     {
 504       g_simple_async_report_error_in_idle (G_OBJECT (stream),
 505                                            callback,
 506                                            user_data,
 507                                            G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
 508                                            _("Too large count value passed to %s"),
 509                                            G_STRFUNC);
 510       return;
 511     }
 512
 513   if (!g_input_stream_set_pending (G_INPUT_STREAM (stream), &error))
 514     {
 515       g_simple_async_report_take_gerror_in_idle (G_OBJECT (stream),
 516                                             callback,
 517                                             user_data,
 518                                             error);
 519       return;
 520     }
 521
 522   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 523
 524   stream->priv->outstanding_callback = callback;
 525   g_object_ref (stream);
 526   class->fill_async (stream, count, io_priority, cancellable,
 527                      async_fill_callback_wrapper, user_data);
 528 }
 529
 530 /**
 531  * g_buffered_input_stream_fill_finish:
 532  * @stream: a #GBufferedInputStream
 533  * @result: a #GAsyncResult
 534  * @error: a #GError
 535  *
 536  * Finishes an asynchronous read.
 537  *
 538  * Returns: a #gssize of the read stream, or %-1 on an error.
 539  */
 540 gssize
 541 g_buffered_input_stream_fill_finish (GBufferedInputStream  *stream,
 542                                      GAsyncResult          *result,
 543                                      GError               **error)
 544 {
 545   GSimpleAsyncResult *simple;
 546   GBufferedInputStreamClass *class;
 547
 548   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 549   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
 550
 551   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 552     {
 553       simple = G_SIMPLE_ASYNC_RESULT (result);
 554       if (g_simple_async_result_propagate_error (simple, error))
 555         return -1;
 556
 557       /* Special case read of 0 bytes */
 558       if (g_simple_async_result_get_source_tag (simple) == g_buffered_input_stream_fill_async)
 559         return 0;
 560     }
 561
 562   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 563   return class->fill_finish (stream, result, error);
 564 }
 565
 566 /**
 567  * g_buffered_input_stream_get_available:
 568  * @stream: #GBufferedInputStream
 569  *
 570  * Gets the size of the available data within the stream.
 571  *
 572  * Returns: size of the available stream.
 573  */
 574 gsize
 575 g_buffered_input_stream_get_available (GBufferedInputStream *stream)
 576 {
 577   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 578
 579   return stream->priv->end - stream->priv->pos;
 580 }
 581
 582 /**
 583  * g_buffered_input_stream_peek:
 584  * @stream: a #GBufferedInputStream
 585  * @buffer: (array length=count) (element-type guint8): a pointer to
 586  *   an allocated chunk of memory
 587  * @offset: a #gsize
 588  * @count: a #gsize
 589  *
 590  * Peeks in the buffer, copying data of size @count into @buffer,
 591  * offset @offset bytes.
 592  *
 593  * Returns: a #gsize of the number of bytes peeked, or -1 on error.
 594  */
 595 gsize
 596 g_buffered_input_stream_peek (GBufferedInputStream *stream,
 597                               void                 *buffer,
 598                               gsize                 offset,
 599                               gsize                 count)
 600 {
 601   gsize available;
 602   gsize end;
 603
 604   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 605   g_return_val_if_fail (buffer != NULL, -1);
 606
 607   available = g_buffered_input_stream_get_available (stream);
 608
 609   if (offset > available)
 610     return 0;
 611
 612   end = MIN (offset + count, available);
 613   count = end - offset;
 614
 615   memcpy (buffer, stream->priv->buffer + stream->priv->pos + offset, count);
 616   return count;
 617 }
 618
 619 /**
 620  * g_buffered_input_stream_peek_buffer:
 621  * @stream: a #GBufferedInputStream
 622  * @count: (out): a #gsize to get the number of bytes available in the buffer
 623  *
 624  * Returns the buffer with the currently available bytes. The returned
 625  * buffer must not be modified and will become invalid when reading from
 626  * the stream or filling the buffer.
 627  *
 628  * Returns: (array length=count) (element-type guint8) (transfer none):
 629  *          read-only buffer
 630  */
 631 const void*
 632 g_buffered_input_stream_peek_buffer (GBufferedInputStream *stream,
 633                                      gsize                *count)
 634 {
 635   GBufferedInputStreamPrivate *priv;
 636
 637   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), NULL);
 638
 639   priv = stream->priv;
 640
 641   if (count)
 642     *count = priv->end - priv->pos;
 643
 644   return priv->buffer + priv->pos;
 645 }
 646
 647 static void
 648 compact_buffer (GBufferedInputStream *stream)
 649 {
 650   GBufferedInputStreamPrivate *priv;
 651   gsize current_size;
 652
 653   priv = stream->priv;
 654
 655   current_size = priv->end - priv->pos;
 656
 657   g_memmove (priv->buffer, priv->buffer + priv->pos, current_size);
 658
 659   priv->pos = 0;
 660   priv->end = current_size;
 661 }
 662
 663 static gssize
 664 g_buffered_input_stream_real_fill (GBufferedInputStream  *stream,
 665                                    gssize                 count,
 666                                    GCancellable          *cancellable,
 667                                    GError               **error)
 668 {
 669   GBufferedInputStreamPrivate *priv;
 670   GInputStream *base_stream;
 671   gssize nread;
 672   gsize in_buffer;
 673
 674   priv = stream->priv;
 675
 676   if (count == -1)
 677     count = priv->len;
 678
 679   in_buffer = priv->end - priv->pos;
 680
 681   /* Never fill more than can fit in the buffer */
 682   count = MIN (count, priv->len - in_buffer);
 683
 684   /* If requested length does not fit at end, compact */
 685   if (priv->len - priv->end < count)
 686     compact_buffer (stream);
 687
 688   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 689   nread = g_input_stream_read (base_stream,
 690                                priv->buffer + priv->end,
 691                                count,
 692                                cancellable,
 693                                error);
 694
 695   if (nread > 0)
 696     priv->end += nread;
 697
 698   return nread;
 699 }
 700
 701 static gssize
 702 g_buffered_input_stream_skip (GInputStream  *stream,
 703                               gsize          count,
 704                               GCancellable  *cancellable,
 705                               GError       **error)
 706 {
 707   GBufferedInputStream        *bstream;
 708   GBufferedInputStreamPrivate *priv;
 709   GBufferedInputStreamClass *class;
 710   GInputStream *base_stream;
 711   gsize available, bytes_skipped;
 712   gssize nread;
 713
 714   bstream = G_BUFFERED_INPUT_STREAM (stream);
 715   priv = bstream->priv;
 716
 717   available = priv->end - priv->pos;
 718
 719   if (count <= available)
 720     {
 721       priv->pos += count;
 722       return count;
 723     }
 724
 725   /* Full request not available, skip all currently available and
 726    * request refill for more
 727    */
 728
 729   priv->pos = 0;
 730   priv->end = 0;
 731   bytes_skipped = available;
 732   count -= available;
 733
 734   if (bytes_skipped > 0)
 735     error = NULL; /* Ignore further errors if we already read some data */
 736
 737   if (count > priv->len)
 738     {
 739       /* Large request, shortcut buffer */
 740
 741       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 742
 743       nread = g_input_stream_skip (base_stream,
 744                                    count,
 745                                    cancellable,
 746                                    error);
 747
 748       if (nread < 0 && bytes_skipped == 0)
 749         return -1;
 750
 751       if (nread > 0)
 752         bytes_skipped += nread;
 753
 754       return bytes_skipped;
 755     }
 756
 757   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 758   nread = class->fill (bstream, priv->len, cancellable, error);
 759
 760   if (nread < 0)
 761     {
 762       if (bytes_skipped == 0)
 763         return -1;
 764       else
 765         return bytes_skipped;
 766     }
 767
 768   available = priv->end - priv->pos;
 769   count = MIN (count, available);
 770
 771   bytes_skipped += count;
 772   priv->pos += count;
 773
 774   return bytes_skipped;
 775 }
 776
 777 static gssize
 778 g_buffered_input_stream_read (GInputStream *stream,
 779                               void         *buffer,
 780                               gsize         count,
 781                               GCancellable *cancellable,
 782                               GError      **error)
 783 {
 784   GBufferedInputStream        *bstream;
 785   GBufferedInputStreamPrivate *priv;
 786   GBufferedInputStreamClass *class;
 787   GInputStream *base_stream;
 788   gsize available, bytes_read;
 789   gssize nread;
 790
 791   bstream = G_BUFFERED_INPUT_STREAM (stream);
 792   priv = bstream->priv;
 793
 794   available = priv->end - priv->pos;
 795
 796   if (count <= available)
 797     {
 798       memcpy (buffer, priv->buffer + priv->pos, count);
 799       priv->pos += count;
 800       return count;
 801     }
 802
 803   /* Full request not available, read all currently available and
 804    * request refill for more
 805    */
 806
 807   memcpy (buffer, priv->buffer + priv->pos, available);
 808   priv->pos = 0;
 809   priv->end = 0;
 810   bytes_read = available;
 811   count -= available;
 812
 813   if (bytes_read > 0)
 814     error = NULL; /* Ignore further errors if we already read some data */
 815
 816   if (count > priv->len)
 817     {
 818       /* Large request, shortcut buffer */
 819
 820       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 821
 822       nread = g_input_stream_read (base_stream,
 823                                    (char *)buffer + bytes_read,
 824                                    count,
 825                                    cancellable,
 826                                    error);
 827
 828       if (nread < 0 && bytes_read == 0)
 829         return -1;
 830
 831       if (nread > 0)
 832         bytes_read += nread;
 833
 834       return bytes_read;
 835     }
 836
 837   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 838   nread = class->fill (bstream, priv->len, cancellable, error);
 839   if (nread < 0)
 840     {
 841       if (bytes_read == 0)
 842         return -1;
 843       else
 844         return bytes_read;
 845     }
 846
 847   available = priv->end - priv->pos;
 848   count = MIN (count, available);
 849
 850   memcpy ((char *)buffer + bytes_read, (char *)priv->buffer + priv->pos, count);
 851   bytes_read += count;
 852   priv->pos += count;
 853
 854   return bytes_read;
 855 }
 856
 857 static goffset
 858 g_buffered_input_stream_tell (GSeekable *seekable)
 859 {
 860   GBufferedInputStream        *bstream;
 861   GBufferedInputStreamPrivate *priv;
 862   GInputStream *base_stream;
 863   GSeekable    *base_stream_seekable;
 864   gsize available;
 865   goffset base_offset;
 866
 867   bstream = G_BUFFERED_INPUT_STREAM (seekable);
 868   priv = bstream->priv;
 869
 870   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 871   if (!G_IS_SEEKABLE (base_stream))
 872     return 0;
 873   base_stream_seekable = G_SEEKABLE (base_stream);
 874
 875   available = priv->end - priv->pos;
 876   base_offset = g_seekable_tell (base_stream_seekable);
 877
 878   return base_offset - available;
 879 }
 880
 881 static gboolean
 882 g_buffered_input_stream_can_seek (GSeekable *seekable)
 883 {
 884   GInputStream *base_stream;
 885
 886   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 887   return G_IS_SEEKABLE (base_stream) && g_seekable_can_seek (G_SEEKABLE (base_stream));
 888 }
 889
 890 static gboolean
 891 g_buffered_input_stream_seek (GSeekable     *seekable,
 892                               goffset        offset,
 893                               GSeekType      type,
 894                               GCancellable  *cancellable,
 895                               GError       **error)
 896 {
 897   GBufferedInputStream        *bstream;
 898   GBufferedInputStreamPrivate *priv;
 899   GInputStream *base_stream;
 900   GSeekable *base_stream_seekable;
 901
 902   bstream = G_BUFFERED_INPUT_STREAM (seekable);
 903   priv = bstream->priv;
 904
 905   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 906   if (!G_IS_SEEKABLE (base_stream))
 907     {
 908       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 909                            _("Seek not supported on base stream"));
 910       return FALSE;
 911     }
 912
 913   base_stream_seekable = G_SEEKABLE (base_stream);
 914
 915   if (type == G_SEEK_CUR)
 916     {
 917       if (offset <= priv->end - priv->pos && offset >= -priv->pos)
 918         {
 919           priv->pos += offset;
 920           return TRUE;
 921         }
 922       else
 923         {
 924           offset -= priv->end - priv->pos;
 925         }
 926     }
 927
 928   if (g_seekable_seek (base_stream_seekable, offset, type, cancellable, error))
 929     {
 930       priv->pos = 0;
 931       priv->end = 0;
 932       return TRUE;
 933     }
 934   else
 935     {
 936       return FALSE;
 937     }
 938 }
 939
 940 static gboolean
 941 g_buffered_input_stream_can_truncate (GSeekable *seekable)
 942 {
 943   return FALSE;
 944 }
 945
 946 static gboolean
 947 g_buffered_input_stream_truncate (GSeekable     *seekable,
 948                                   goffset        offset,
 949                                   GCancellable  *cancellable,
 950                                   GError       **error)
 951 {
 952   g_set_error_literal (error,
 953                        G_IO_ERROR,
 954                        G_IO_ERROR_NOT_SUPPORTED,
 955                        _("Cannot truncate GBufferedInputStream"));
 956   return FALSE;
 957 }
 958
 959 /**
 960  * g_buffered_input_stream_read_byte:
 961  * @stream: a #GBufferedInputStream
 962  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 963  * @error: location to store the error occurring, or %NULL to ignore
 964  *
 965  * Tries to read a single byte from the stream or the buffer. Will block
 966  * during this read.
 967  *
 968  * On success, the byte read from the stream is returned. On end of stream
 969  * -1 is returned but it's not an exceptional error and @error is not set.
 970  *
 971  * If @cancellable is not %NULL, then the operation can be cancelled by
 972  * triggering the cancellable object from another thread. If the operation
 973  * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
 974  * operation was partially finished when the operation was cancelled the
 975  * partial result will be returned, without an error.
 976  *
 977  * On error -1 is returned and @error is set accordingly.
 978  *
 979  * Returns: the byte read from the @stream, or -1 on end of stream or error.
 980  */
 981 int
 982 g_buffered_input_stream_read_byte (GBufferedInputStream  *stream,
 983                                    GCancellable          *cancellable,
 984                                    GError               **error)
 985 {
 986   GBufferedInputStreamPrivate *priv;
 987   GBufferedInputStreamClass *class;
 988   GInputStream *input_stream;
 989   gsize available;
 990   gssize nread;
 991
 992   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 993
 994   priv = stream->priv;
 995   input_stream = G_INPUT_STREAM (stream);
 996
 997   if (g_input_stream_is_closed (input_stream))
 998     {
 999       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
1000                            _("Stream is already closed"));
1001       return -1;
1002     }
1003
1004   if (!g_input_stream_set_pending (input_stream, error))
1005     return -1;
1006
1007   available = priv->end - priv->pos;
1008
1009   if (available != 0)
1010     {
1011       g_input_stream_clear_pending (input_stream);
1012       return priv->buffer[priv->pos++];
1013     }
1014
1015   /* Byte not available, request refill for more */
1016
1017   if (cancellable)
1018     g_cancellable_push_current (cancellable);
1019
1020   priv->pos = 0;
1021   priv->end = 0;
1022
1023   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
1024   nread = class->fill (stream, priv->len, cancellable, error);
1025
1026   if (cancellable)
1027     g_cancellable_pop_current (cancellable);
1028
1029   g_input_stream_clear_pending (input_stream);
1030
1031   if (nread <= 0)
1032     return -1; /* error or end of stream */
1033
1034   return priv->buffer[priv->pos++];
1035 }
1036
1037 /* ************************** */
1038 /* Async stuff implementation */
1039 /* ************************** */
1040
1041 static void
1042 fill_async_callback (GObject      *source_object,
1043                      GAsyncResult *result,
1044                      gpointer      user_data)
1045 {
1046   GError *error;
1047   gssize res;
1048   GSimpleAsyncResult *simple;
1049
1050   simple = user_data;
1051
1052   error = NULL;
1053   res = g_input_stream_read_finish (G_INPUT_STREAM (source_object),
1054                                     result, &error);
1055
1056   g_simple_async_result_set_op_res_gssize (simple, res);
1057   if (res == -1)
1058     {
1059       g_simple_async_result_take_error (simple, error);
1060     }
1061   else
1062     {
1063       GBufferedInputStreamPrivate *priv;
1064       GObject *object;
1065
1066       object = g_async_result_get_source_object (G_ASYNC_RESULT (simple));
1067       priv = G_BUFFERED_INPUT_STREAM (object)->priv;
1068
1069       g_assert_cmpint (priv->end + res, <=, priv->len);
1070       priv->end += res;
1071
1072       g_object_unref (object);
1073     }
1074
1075   /* Complete immediately, not in idle, since we're already
1076    * in a mainloop callout
1077    */
1078   g_simple_async_result_complete (simple);
1079   g_object_unref (simple);
1080 }
1081
1082 static void
1083 g_buffered_input_stream_real_fill_async (GBufferedInputStream *stream,
1084                                          gssize                count,
1085                                          int                   io_priority,
1086                                          GCancellable         *cancellable,
1087                                          GAsyncReadyCallback   callback,
1088                                          gpointer              user_data)
1089 {
1090   GBufferedInputStreamPrivate *priv;
1091   GInputStream *base_stream;
1092   GSimpleAsyncResult *simple;
1093   gsize in_buffer;
1094
1095   priv = stream->priv;
1096
1097   if (count == -1)
1098     count = priv->len;
1099
1100   in_buffer = priv->end - priv->pos;
1101
1102   /* Never fill more than can fit in the buffer */
1103   count = MIN (count, priv->len - in_buffer);
1104
1105   /* If requested length does not fit at end, compact */
1106   if (priv->len - priv->end < count)
1107     compact_buffer (stream);
1108
1109   simple = g_simple_async_result_new (G_OBJECT (stream),
1110                                       callback, user_data,
1111                                       g_buffered_input_stream_real_fill_async);
1112
1113   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
1114   g_input_stream_read_async (base_stream,
1115                              priv->buffer + priv->end,
1116                              count,
1117                              io_priority,
1118                              cancellable,
1119                              fill_async_callback,
1120                              simple);
1121 }
1122
1123 static gssize
1124 g_buffered_input_stream_real_fill_finish (GBufferedInputStream *stream,
1125                                           GAsyncResult         *result,
1126                                           GError              **error)
1127 {
1128   GSimpleAsyncResult *simple;
1129   gssize nread;
1130
1131   simple = G_SIMPLE_ASYNC_RESULT (result);
1132   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_buffered_input_stream_real_fill_async);
1133
1134   nread = g_simple_async_result_get_op_res_gssize (simple);
1135   return nread;
1136 }
1137
1138 typedef struct
1139 {
1140   gssize bytes_skipped;
1141   gssize count;
1142 } SkipAsyncData;
1143
1144 static void
1145 free_skip_async_data (gpointer _data)
1146 {
1147   SkipAsyncData *data = _data;
1148   g_slice_free (SkipAsyncData, data);
1149 }
1150
1151 static void
1152 large_skip_callback (GObject      *source_object,
1153                      GAsyncResult *result,
1154                      gpointer      user_data)
1155 {
1156   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (user_data);
1157   SkipAsyncData *data;
1158   GError *error;
1159   gssize nread;
1160
1161   data = g_simple_async_result_get_op_res_gpointer (simple);
1162
1163   error = NULL;
1164   nread = g_input_stream_skip_finish (G_INPUT_STREAM (source_object),
1165                                       result, &error);
1166
1167   /* Only report the error if we've not already read some data */
1168   if (nread < 0 && data->bytes_skipped == 0)
1169     g_simple_async_result_take_error (simple, error);
1170   else if (error)
1171     g_error_free (error);
1172
1173   if (nread > 0)
1174     data->bytes_skipped += nread;
1175
1176   /* Complete immediately, not in idle, since we're already
1177    * in a mainloop callout
1178    */
1179   g_simple_async_result_complete (simple);
1180   g_object_unref (simple);
1181 }
1182
1183 static void
1184 skip_fill_buffer_callback (GObject      *source_object,
1185                            GAsyncResult *result,
1186                            gpointer      user_data)
1187 {
1188   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (user_data);
1189   GBufferedInputStream *bstream;
1190   GBufferedInputStreamPrivate *priv;
1191   SkipAsyncData *data;
1192   GError *error;
1193   gssize nread;
1194   gsize available;
1195
1196   bstream = G_BUFFERED_INPUT_STREAM (source_object);
1197   priv = bstream->priv;
1198
1199   data = g_simple_async_result_get_op_res_gpointer (simple);
1200
1201   error = NULL;
1202   nread = g_buffered_input_stream_fill_finish (bstream,
1203                                                result, &error);
1204
1205   if (nread < 0 && data->bytes_skipped == 0)
1206     g_simple_async_result_take_error (simple, error);
1207   else if (error)
1208     g_error_free (error);
1209
1210   if (nread > 0)
1211     {
1212       available = priv->end - priv->pos;
1213       data->count = MIN (data->count, available);
1214
1215       data->bytes_skipped += data->count;
1216       priv->pos += data->count;
1217     }
1218
1219   /* Complete immediately, not in idle, since we're already
1220    * in a mainloop callout
1221    */
1222   g_simple_async_result_complete (simple);
1223   g_object_unref (simple);
1224 }
1225
1226 static void
1227 g_buffered_input_stream_skip_async (GInputStream        *stream,
1228                                     gsize                count,
1229                                     int                  io_priority,
1230                                     GCancellable        *cancellable,
1231                                     GAsyncReadyCallback  callback,
1232                                     gpointer             user_data)
1233 {
1234   GBufferedInputStream *bstream;
1235   GBufferedInputStreamPrivate *priv;
1236   GBufferedInputStreamClass *class;
1237   GInputStream *base_stream;
1238   gsize available;
1239   GSimpleAsyncResult *simple;
1240   SkipAsyncData *data;
1241
1242   bstream = G_BUFFERED_INPUT_STREAM (stream);
1243   priv = bstream->priv;
1244
1245   data = g_slice_new (SkipAsyncData);
1246   data->bytes_skipped = 0;
1247   simple = g_simple_async_result_new (G_OBJECT (stream),
1248                                       callback, user_data,
1249                                       g_buffered_input_stream_skip_async);
1250   g_simple_async_result_set_op_res_gpointer (simple, data, free_skip_async_data);
1251
1252   available = priv->end - priv->pos;
1253
1254   if (count <= available)
1255     {
1256       priv->pos += count;
1257       data->bytes_skipped = count;
1258
1259       g_simple_async_result_complete_in_idle (simple);
1260       g_object_unref (simple);
1261       return;
1262     }
1263
1264   /* Full request not available, skip all currently available
1265    * and request refill for more
1266    */
1267
1268   priv->pos = 0;
1269   priv->end = 0;
1270
1271   count -= available;
1272
1273   data->bytes_skipped = available;
1274   data->count = count;
1275
1276   if (count > priv->len)
1277     {
1278       /* Large request, shortcut buffer */
1279
1280       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
1281
1282       g_input_stream_skip_async (base_stream,
1283                                  count,
1284                                  io_priority, cancellable,
1285                                  large_skip_callback,
1286                                  simple);
1287     }
1288   else
1289     {
1290       class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
1291       class->fill_async (bstream, priv->len, io_priority, cancellable,
1292                          skip_fill_buffer_callback, simple);
1293     }
1294 }
1295
1296 static gssize
1297 g_buffered_input_stream_skip_finish (GInputStream   *stream,
1298                                      GAsyncResult   *result,
1299                                      GError        **error)
1300 {
1301   GSimpleAsyncResult *simple;
1302   SkipAsyncData *data;
1303
1304   simple = G_SIMPLE_ASYNC_RESULT (result);
1305
1306   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_buffered_input_stream_skip_async);
1307
1308   data = g_simple_async_result_get_op_res_gpointer (simple);
1309
1310   return data->bytes_skipped;
1311 }