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   GBufferedInputStreamClass *class;
 546
 547   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 548   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
 549
 550   if (g_async_result_legacy_propagate_error (result, error))
 551     return -1;
 552   else if (g_async_result_is_tagged (result, g_buffered_input_stream_fill_async))
 553     {
 554       /* Special case read of 0 bytes */
 555       return 0;
 556     }
 557
 558   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 559   return class->fill_finish (stream, result, error);
 560 }
 561
 562 /**
 563  * g_buffered_input_stream_get_available:
 564  * @stream: #GBufferedInputStream
 565  *
 566  * Gets the size of the available data within the stream.
 567  *
 568  * Returns: size of the available stream.
 569  */
 570 gsize
 571 g_buffered_input_stream_get_available (GBufferedInputStream *stream)
 572 {
 573   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 574
 575   return stream->priv->end - stream->priv->pos;
 576 }
 577
 578 /**
 579  * g_buffered_input_stream_peek:
 580  * @stream: a #GBufferedInputStream
 581  * @buffer: (array length=count) (element-type guint8): a pointer to
 582  *   an allocated chunk of memory
 583  * @offset: a #gsize
 584  * @count: a #gsize
 585  *
 586  * Peeks in the buffer, copying data of size @count into @buffer,
 587  * offset @offset bytes.
 588  *
 589  * Returns: a #gsize of the number of bytes peeked, or -1 on error.
 590  */
 591 gsize
 592 g_buffered_input_stream_peek (GBufferedInputStream *stream,
 593                               void                 *buffer,
 594                               gsize                 offset,
 595                               gsize                 count)
 596 {
 597   gsize available;
 598   gsize end;
 599
 600   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 601   g_return_val_if_fail (buffer != NULL, -1);
 602
 603   available = g_buffered_input_stream_get_available (stream);
 604
 605   if (offset > available)
 606     return 0;
 607
 608   end = MIN (offset + count, available);
 609   count = end - offset;
 610
 611   memcpy (buffer, stream->priv->buffer + stream->priv->pos + offset, count);
 612   return count;
 613 }
 614
 615 /**
 616  * g_buffered_input_stream_peek_buffer:
 617  * @stream: a #GBufferedInputStream
 618  * @count: (out): a #gsize to get the number of bytes available in the buffer
 619  *
 620  * Returns the buffer with the currently available bytes. The returned
 621  * buffer must not be modified and will become invalid when reading from
 622  * the stream or filling the buffer.
 623  *
 624  * Returns: (array length=count) (element-type guint8) (transfer none):
 625  *          read-only buffer
 626  */
 627 const void*
 628 g_buffered_input_stream_peek_buffer (GBufferedInputStream *stream,
 629                                      gsize                *count)
 630 {
 631   GBufferedInputStreamPrivate *priv;
 632
 633   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), NULL);
 634
 635   priv = stream->priv;
 636
 637   if (count)
 638     *count = priv->end - priv->pos;
 639
 640   return priv->buffer + priv->pos;
 641 }
 642
 643 static void
 644 compact_buffer (GBufferedInputStream *stream)
 645 {
 646   GBufferedInputStreamPrivate *priv;
 647   gsize current_size;
 648
 649   priv = stream->priv;
 650
 651   current_size = priv->end - priv->pos;
 652
 653   g_memmove (priv->buffer, priv->buffer + priv->pos, current_size);
 654
 655   priv->pos = 0;
 656   priv->end = current_size;
 657 }
 658
 659 static gssize
 660 g_buffered_input_stream_real_fill (GBufferedInputStream  *stream,
 661                                    gssize                 count,
 662                                    GCancellable          *cancellable,
 663                                    GError               **error)
 664 {
 665   GBufferedInputStreamPrivate *priv;
 666   GInputStream *base_stream;
 667   gssize nread;
 668   gsize in_buffer;
 669
 670   priv = stream->priv;
 671
 672   if (count == -1)
 673     count = priv->len;
 674
 675   in_buffer = priv->end - priv->pos;
 676
 677   /* Never fill more than can fit in the buffer */
 678   count = MIN (count, priv->len - in_buffer);
 679
 680   /* If requested length does not fit at end, compact */
 681   if (priv->len - priv->end < count)
 682     compact_buffer (stream);
 683
 684   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 685   nread = g_input_stream_read (base_stream,
 686                                priv->buffer + priv->end,
 687                                count,
 688                                cancellable,
 689                                error);
 690
 691   if (nread > 0)
 692     priv->end += nread;
 693
 694   return nread;
 695 }
 696
 697 static gssize
 698 g_buffered_input_stream_skip (GInputStream  *stream,
 699                               gsize          count,
 700                               GCancellable  *cancellable,
 701                               GError       **error)
 702 {
 703   GBufferedInputStream        *bstream;
 704   GBufferedInputStreamPrivate *priv;
 705   GBufferedInputStreamClass *class;
 706   GInputStream *base_stream;
 707   gsize available, bytes_skipped;
 708   gssize nread;
 709
 710   bstream = G_BUFFERED_INPUT_STREAM (stream);
 711   priv = bstream->priv;
 712
 713   available = priv->end - priv->pos;
 714
 715   if (count <= available)
 716     {
 717       priv->pos += count;
 718       return count;
 719     }
 720
 721   /* Full request not available, skip all currently available and
 722    * request refill for more
 723    */
 724
 725   priv->pos = 0;
 726   priv->end = 0;
 727   bytes_skipped = available;
 728   count -= available;
 729
 730   if (bytes_skipped > 0)
 731     error = NULL; /* Ignore further errors if we already read some data */
 732
 733   if (count > priv->len)
 734     {
 735       /* Large request, shortcut buffer */
 736
 737       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 738
 739       nread = g_input_stream_skip (base_stream,
 740                                    count,
 741                                    cancellable,
 742                                    error);
 743
 744       if (nread < 0 && bytes_skipped == 0)
 745         return -1;
 746
 747       if (nread > 0)
 748         bytes_skipped += nread;
 749
 750       return bytes_skipped;
 751     }
 752
 753   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 754   nread = class->fill (bstream, priv->len, cancellable, error);
 755
 756   if (nread < 0)
 757     {
 758       if (bytes_skipped == 0)
 759         return -1;
 760       else
 761         return bytes_skipped;
 762     }
 763
 764   available = priv->end - priv->pos;
 765   count = MIN (count, available);
 766
 767   bytes_skipped += count;
 768   priv->pos += count;
 769
 770   return bytes_skipped;
 771 }
 772
 773 static gssize
 774 g_buffered_input_stream_read (GInputStream *stream,
 775                               void         *buffer,
 776                               gsize         count,
 777                               GCancellable *cancellable,
 778                               GError      **error)
 779 {
 780   GBufferedInputStream        *bstream;
 781   GBufferedInputStreamPrivate *priv;
 782   GBufferedInputStreamClass *class;
 783   GInputStream *base_stream;
 784   gsize available, bytes_read;
 785   gssize nread;
 786
 787   bstream = G_BUFFERED_INPUT_STREAM (stream);
 788   priv = bstream->priv;
 789
 790   available = priv->end - priv->pos;
 791
 792   if (count <= available)
 793     {
 794       memcpy (buffer, priv->buffer + priv->pos, count);
 795       priv->pos += count;
 796       return count;
 797     }
 798
 799   /* Full request not available, read all currently available and
 800    * request refill for more
 801    */
 802
 803   memcpy (buffer, priv->buffer + priv->pos, available);
 804   priv->pos = 0;
 805   priv->end = 0;
 806   bytes_read = available;
 807   count -= available;
 808
 809   if (bytes_read > 0)
 810     error = NULL; /* Ignore further errors if we already read some data */
 811
 812   if (count > priv->len)
 813     {
 814       /* Large request, shortcut buffer */
 815
 816       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 817
 818       nread = g_input_stream_read (base_stream,
 819                                    (char *)buffer + bytes_read,
 820                                    count,
 821                                    cancellable,
 822                                    error);
 823
 824       if (nread < 0 && bytes_read == 0)
 825         return -1;
 826
 827       if (nread > 0)
 828         bytes_read += nread;
 829
 830       return bytes_read;
 831     }
 832
 833   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 834   nread = class->fill (bstream, priv->len, cancellable, error);
 835   if (nread < 0)
 836     {
 837       if (bytes_read == 0)
 838         return -1;
 839       else
 840         return bytes_read;
 841     }
 842
 843   available = priv->end - priv->pos;
 844   count = MIN (count, available);
 845
 846   memcpy ((char *)buffer + bytes_read, (char *)priv->buffer + priv->pos, count);
 847   bytes_read += count;
 848   priv->pos += count;
 849
 850   return bytes_read;
 851 }
 852
 853 static goffset
 854 g_buffered_input_stream_tell (GSeekable *seekable)
 855 {
 856   GBufferedInputStream        *bstream;
 857   GBufferedInputStreamPrivate *priv;
 858   GInputStream *base_stream;
 859   GSeekable    *base_stream_seekable;
 860   gsize available;
 861   goffset base_offset;
 862
 863   bstream = G_BUFFERED_INPUT_STREAM (seekable);
 864   priv = bstream->priv;
 865
 866   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 867   if (!G_IS_SEEKABLE (base_stream))
 868     return 0;
 869   base_stream_seekable = G_SEEKABLE (base_stream);
 870
 871   available = priv->end - priv->pos;
 872   base_offset = g_seekable_tell (base_stream_seekable);
 873
 874   return base_offset - available;
 875 }
 876
 877 static gboolean
 878 g_buffered_input_stream_can_seek (GSeekable *seekable)
 879 {
 880   GInputStream *base_stream;
 881
 882   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 883   return G_IS_SEEKABLE (base_stream) && g_seekable_can_seek (G_SEEKABLE (base_stream));
 884 }
 885
 886 static gboolean
 887 g_buffered_input_stream_seek (GSeekable     *seekable,
 888                               goffset        offset,
 889                               GSeekType      type,
 890                               GCancellable  *cancellable,
 891                               GError       **error)
 892 {
 893   GBufferedInputStream        *bstream;
 894   GBufferedInputStreamPrivate *priv;
 895   GInputStream *base_stream;
 896   GSeekable *base_stream_seekable;
 897
 898   bstream = G_BUFFERED_INPUT_STREAM (seekable);
 899   priv = bstream->priv;
 900
 901   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 902   if (!G_IS_SEEKABLE (base_stream))
 903     {
 904       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 905                            _("Seek not supported on base stream"));
 906       return FALSE;
 907     }
 908
 909   base_stream_seekable = G_SEEKABLE (base_stream);
 910
 911   if (type == G_SEEK_CUR)
 912     {
 913       if (offset <= priv->end - priv->pos && offset >= -priv->pos)
 914         {
 915           priv->pos += offset;
 916           return TRUE;
 917         }
 918       else
 919         {
 920           offset -= priv->end - priv->pos;
 921         }
 922     }
 923
 924   if (g_seekable_seek (base_stream_seekable, offset, type, cancellable, error))
 925     {
 926       priv->pos = 0;
 927       priv->end = 0;
 928       return TRUE;
 929     }
 930   else
 931     {
 932       return FALSE;
 933     }
 934 }
 935
 936 static gboolean
 937 g_buffered_input_stream_can_truncate (GSeekable *seekable)
 938 {
 939   return FALSE;
 940 }
 941
 942 static gboolean
 943 g_buffered_input_stream_truncate (GSeekable     *seekable,
 944                                   goffset        offset,
 945                                   GCancellable  *cancellable,
 946                                   GError       **error)
 947 {
 948   g_set_error_literal (error,
 949                        G_IO_ERROR,
 950                        G_IO_ERROR_NOT_SUPPORTED,
 951                        _("Cannot truncate GBufferedInputStream"));
 952   return FALSE;
 953 }
 954
 955 /**
 956  * g_buffered_input_stream_read_byte:
 957  * @stream: a #GBufferedInputStream
 958  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 959  * @error: location to store the error occurring, or %NULL to ignore
 960  *
 961  * Tries to read a single byte from the stream or the buffer. Will block
 962  * during this read.
 963  *
 964  * On success, the byte read from the stream is returned. On end of stream
 965  * -1 is returned but it's not an exceptional error and @error is not set.
 966  *
 967  * If @cancellable is not %NULL, then the operation can be cancelled by
 968  * triggering the cancellable object from another thread. If the operation
 969  * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
 970  * operation was partially finished when the operation was cancelled the
 971  * partial result will be returned, without an error.
 972  *
 973  * On error -1 is returned and @error is set accordingly.
 974  *
 975  * Returns: the byte read from the @stream, or -1 on end of stream or error.
 976  */
 977 int
 978 g_buffered_input_stream_read_byte (GBufferedInputStream  *stream,
 979                                    GCancellable          *cancellable,
 980                                    GError               **error)
 981 {
 982   GBufferedInputStreamPrivate *priv;
 983   GBufferedInputStreamClass *class;
 984   GInputStream *input_stream;
 985   gsize available;
 986   gssize nread;
 987
 988   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 989
 990   priv = stream->priv;
 991   input_stream = G_INPUT_STREAM (stream);
 992
 993   if (g_input_stream_is_closed (input_stream))
 994     {
 995       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 996                            _("Stream is already closed"));
 997       return -1;
 998     }
 999
1000   if (!g_input_stream_set_pending (input_stream, error))
1001     return -1;
1002
1003   available = priv->end - priv->pos;
1004
1005   if (available != 0)
1006     {
1007       g_input_stream_clear_pending (input_stream);
1008       return priv->buffer[priv->pos++];
1009     }
1010
1011   /* Byte not available, request refill for more */
1012
1013   if (cancellable)
1014     g_cancellable_push_current (cancellable);
1015
1016   priv->pos = 0;
1017   priv->end = 0;
1018
1019   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
1020   nread = class->fill (stream, priv->len, cancellable, error);
1021
1022   if (cancellable)
1023     g_cancellable_pop_current (cancellable);
1024
1025   g_input_stream_clear_pending (input_stream);
1026
1027   if (nread <= 0)
1028     return -1; /* error or end of stream */
1029
1030   return priv->buffer[priv->pos++];
1031 }
1032
1033 /* ************************** */
1034 /* Async stuff implementation */
1035 /* ************************** */
1036
1037 static void
1038 fill_async_callback (GObject      *source_object,
1039                      GAsyncResult *result,
1040                      gpointer      user_data)
1041 {
1042   GError *error;
1043   gssize res;
1044   GSimpleAsyncResult *simple;
1045
1046   simple = user_data;
1047
1048   error = NULL;
1049   res = g_input_stream_read_finish (G_INPUT_STREAM (source_object),
1050                                     result, &error);
1051
1052   g_simple_async_result_set_op_res_gssize (simple, res);
1053   if (res == -1)
1054     {
1055       g_simple_async_result_take_error (simple, error);
1056     }
1057   else
1058     {
1059       GBufferedInputStreamPrivate *priv;
1060       GObject *object;
1061
1062       object = g_async_result_get_source_object (G_ASYNC_RESULT (simple));
1063       priv = G_BUFFERED_INPUT_STREAM (object)->priv;
1064
1065       g_assert_cmpint (priv->end + res, <=, priv->len);
1066       priv->end += res;
1067
1068       g_object_unref (object);
1069     }
1070
1071   /* Complete immediately, not in idle, since we're already
1072    * in a mainloop callout
1073    */
1074   g_simple_async_result_complete (simple);
1075   g_object_unref (simple);
1076 }
1077
1078 static void
1079 g_buffered_input_stream_real_fill_async (GBufferedInputStream *stream,
1080                                          gssize                count,
1081                                          int                   io_priority,
1082                                          GCancellable         *cancellable,
1083                                          GAsyncReadyCallback   callback,
1084                                          gpointer              user_data)
1085 {
1086   GBufferedInputStreamPrivate *priv;
1087   GInputStream *base_stream;
1088   GSimpleAsyncResult *simple;
1089   gsize in_buffer;
1090
1091   priv = stream->priv;
1092
1093   if (count == -1)
1094     count = priv->len;
1095
1096   in_buffer = priv->end - priv->pos;
1097
1098   /* Never fill more than can fit in the buffer */
1099   count = MIN (count, priv->len - in_buffer);
1100
1101   /* If requested length does not fit at end, compact */
1102   if (priv->len - priv->end < count)
1103     compact_buffer (stream);
1104
1105   simple = g_simple_async_result_new (G_OBJECT (stream),
1106                                       callback, user_data,
1107                                       g_buffered_input_stream_real_fill_async);
1108
1109   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
1110   g_input_stream_read_async (base_stream,
1111                              priv->buffer + priv->end,
1112                              count,
1113                              io_priority,
1114                              cancellable,
1115                              fill_async_callback,
1116                              simple);
1117 }
1118
1119 static gssize
1120 g_buffered_input_stream_real_fill_finish (GBufferedInputStream *stream,
1121                                           GAsyncResult         *result,
1122                                           GError              **error)
1123 {
1124   GSimpleAsyncResult *simple;
1125   gssize nread;
1126
1127   simple = G_SIMPLE_ASYNC_RESULT (result);
1128   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_buffered_input_stream_real_fill_async);
1129
1130   if (g_simple_async_result_propagate_error (simple, error))
1131     return -1;
1132
1133   nread = g_simple_async_result_get_op_res_gssize (simple);
1134   return nread;
1135 }
1136
1137 typedef struct
1138 {
1139   gssize bytes_skipped;
1140   gssize count;
1141 } SkipAsyncData;
1142
1143 static void
1144 free_skip_async_data (gpointer _data)
1145 {
1146   SkipAsyncData *data = _data;
1147   g_slice_free (SkipAsyncData, data);
1148 }
1149
1150 static void
1151 large_skip_callback (GObject      *source_object,
1152                      GAsyncResult *result,
1153                      gpointer      user_data)
1154 {
1155   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (user_data);
1156   SkipAsyncData *data;
1157   GError *error;
1158   gssize nread;
1159
1160   data = g_simple_async_result_get_op_res_gpointer (simple);
1161
1162   error = NULL;
1163   nread = g_input_stream_skip_finish (G_INPUT_STREAM (source_object),
1164                                       result, &error);
1165
1166   /* Only report the error if we've not already read some data */
1167   if (nread < 0 && data->bytes_skipped == 0)
1168     g_simple_async_result_take_error (simple, error);
1169   else if (error)
1170     g_error_free (error);
1171
1172   if (nread > 0)
1173     data->bytes_skipped += nread;
1174
1175   /* Complete immediately, not in idle, since we're already
1176    * in a mainloop callout
1177    */
1178   g_simple_async_result_complete (simple);
1179   g_object_unref (simple);
1180 }
1181
1182 static void
1183 skip_fill_buffer_callback (GObject      *source_object,
1184                            GAsyncResult *result,
1185                            gpointer      user_data)
1186 {
1187   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (user_data);
1188   GBufferedInputStream *bstream;
1189   GBufferedInputStreamPrivate *priv;
1190   SkipAsyncData *data;
1191   GError *error;
1192   gssize nread;
1193   gsize available;
1194
1195   bstream = G_BUFFERED_INPUT_STREAM (source_object);
1196   priv = bstream->priv;
1197
1198   data = g_simple_async_result_get_op_res_gpointer (simple);
1199
1200   error = NULL;
1201   nread = g_buffered_input_stream_fill_finish (bstream,
1202                                                result, &error);
1203
1204   if (nread < 0 && data->bytes_skipped == 0)
1205     g_simple_async_result_take_error (simple, error);
1206   else if (error)
1207     g_error_free (error);
1208
1209   if (nread > 0)
1210     {
1211       available = priv->end - priv->pos;
1212       data->count = MIN (data->count, available);
1213
1214       data->bytes_skipped += data->count;
1215       priv->pos += data->count;
1216     }
1217
1218   /* Complete immediately, not in idle, since we're already
1219    * in a mainloop callout
1220    */
1221   g_simple_async_result_complete (simple);
1222   g_object_unref (simple);
1223 }
1224
1225 static void
1226 g_buffered_input_stream_skip_async (GInputStream        *stream,
1227                                     gsize                count,
1228                                     int                  io_priority,
1229                                     GCancellable        *cancellable,
1230                                     GAsyncReadyCallback  callback,
1231                                     gpointer             user_data)
1232 {
1233   GBufferedInputStream *bstream;
1234   GBufferedInputStreamPrivate *priv;
1235   GBufferedInputStreamClass *class;
1236   GInputStream *base_stream;
1237   gsize available;
1238   GSimpleAsyncResult *simple;
1239   SkipAsyncData *data;
1240
1241   bstream = G_BUFFERED_INPUT_STREAM (stream);
1242   priv = bstream->priv;
1243
1244   data = g_slice_new (SkipAsyncData);
1245   data->bytes_skipped = 0;
1246   simple = g_simple_async_result_new (G_OBJECT (stream),
1247                                       callback, user_data,
1248                                       g_buffered_input_stream_skip_async);
1249   g_simple_async_result_set_op_res_gpointer (simple, data, free_skip_async_data);
1250
1251   available = priv->end - priv->pos;
1252
1253   if (count <= available)
1254     {
1255       priv->pos += count;
1256       data->bytes_skipped = count;
1257
1258       g_simple_async_result_complete_in_idle (simple);
1259       g_object_unref (simple);
1260       return;
1261     }
1262
1263   /* Full request not available, skip all currently available
1264    * and request refill for more
1265    */
1266
1267   priv->pos = 0;
1268   priv->end = 0;
1269
1270   count -= available;
1271
1272   data->bytes_skipped = available;
1273   data->count = count;
1274
1275   if (count > priv->len)
1276     {
1277       /* Large request, shortcut buffer */
1278
1279       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
1280
1281       g_input_stream_skip_async (base_stream,
1282                                  count,
1283                                  io_priority, cancellable,
1284                                  large_skip_callback,
1285                                  simple);
1286     }
1287   else
1288     {
1289       class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
1290       class->fill_async (bstream, priv->len, io_priority, cancellable,
1291                          skip_fill_buffer_callback, simple);
1292     }
1293 }
1294
1295 static gssize
1296 g_buffered_input_stream_skip_finish (GInputStream   *stream,
1297                                      GAsyncResult   *result,
1298                                      GError        **error)
1299 {
1300   GSimpleAsyncResult *simple;
1301   SkipAsyncData *data;
1302
1303   simple = G_SIMPLE_ASYNC_RESULT (result);
1304
1305   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_buffered_input_stream_skip_async);
1306
1307   data = g_simple_async_result_get_op_res_gpointer (simple);
1308
1309   return data->bytes_skipped;
1310 }