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 "gtask.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   GError *error = NULL;
 487
 488   g_return_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream));
 489
 490   if (count == 0)
 491     {
 492       GTask *task;
 493
 494       task = g_task_new (stream, cancellable, callback, user_data);
 495       g_task_set_source_tag (task, g_buffered_input_stream_fill_async);
 496       g_task_return_int (task, 0);
 497       g_object_unref (task);
 498       return;
 499     }
 500
 501   if (count < -1)
 502     {
 503       g_task_report_new_error (stream, callback, user_data,
 504                                g_buffered_input_stream_fill_async,
 505                                G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
 506                                _("Too large count value passed to %s"),
 507                                G_STRFUNC);
 508       return;
 509     }
 510
 511   if (!g_input_stream_set_pending (G_INPUT_STREAM (stream), &error))
 512     {
 513       g_task_report_error (stream, callback, user_data,
 514                            g_buffered_input_stream_fill_async,
 515                            error);
 516       return;
 517     }
 518
 519   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 520
 521   stream->priv->outstanding_callback = callback;
 522   g_object_ref (stream);
 523   class->fill_async (stream, count, io_priority, cancellable,
 524                      async_fill_callback_wrapper, user_data);
 525 }
 526
 527 /**
 528  * g_buffered_input_stream_fill_finish:
 529  * @stream: a #GBufferedInputStream
 530  * @result: a #GAsyncResult
 531  * @error: a #GError
 532  *
 533  * Finishes an asynchronous read.
 534  *
 535  * Returns: a #gssize of the read stream, or %-1 on an error.
 536  */
 537 gssize
 538 g_buffered_input_stream_fill_finish (GBufferedInputStream  *stream,
 539                                      GAsyncResult          *result,
 540                                      GError               **error)
 541 {
 542   GBufferedInputStreamClass *class;
 543
 544   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 545   g_return_val_if_fail (G_IS_ASYNC_RESULT (result), -1);
 546
 547   if (g_async_result_legacy_propagate_error (result, error))
 548     return -1;
 549   else if (g_async_result_is_tagged (result, g_buffered_input_stream_fill_async))
 550     return g_task_propagate_int (G_TASK (result), error);
 551
 552   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 553   return class->fill_finish (stream, result, error);
 554 }
 555
 556 /**
 557  * g_buffered_input_stream_get_available:
 558  * @stream: #GBufferedInputStream
 559  *
 560  * Gets the size of the available data within the stream.
 561  *
 562  * Returns: size of the available stream.
 563  */
 564 gsize
 565 g_buffered_input_stream_get_available (GBufferedInputStream *stream)
 566 {
 567   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 568
 569   return stream->priv->end - stream->priv->pos;
 570 }
 571
 572 /**
 573  * g_buffered_input_stream_peek:
 574  * @stream: a #GBufferedInputStream
 575  * @buffer: (array length=count) (element-type guint8): a pointer to
 576  *   an allocated chunk of memory
 577  * @offset: a #gsize
 578  * @count: a #gsize
 579  *
 580  * Peeks in the buffer, copying data of size @count into @buffer,
 581  * offset @offset bytes.
 582  *
 583  * Returns: a #gsize of the number of bytes peeked, or -1 on error.
 584  */
 585 gsize
 586 g_buffered_input_stream_peek (GBufferedInputStream *stream,
 587                               void                 *buffer,
 588                               gsize                 offset,
 589                               gsize                 count)
 590 {
 591   gsize available;
 592   gsize end;
 593
 594   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 595   g_return_val_if_fail (buffer != NULL, -1);
 596
 597   available = g_buffered_input_stream_get_available (stream);
 598
 599   if (offset > available)
 600     return 0;
 601
 602   end = MIN (offset + count, available);
 603   count = end - offset;
 604
 605   memcpy (buffer, stream->priv->buffer + stream->priv->pos + offset, count);
 606   return count;
 607 }
 608
 609 /**
 610  * g_buffered_input_stream_peek_buffer:
 611  * @stream: a #GBufferedInputStream
 612  * @count: (out): a #gsize to get the number of bytes available in the buffer
 613  *
 614  * Returns the buffer with the currently available bytes. The returned
 615  * buffer must not be modified and will become invalid when reading from
 616  * the stream or filling the buffer.
 617  *
 618  * Returns: (array length=count) (element-type guint8) (transfer none):
 619  *          read-only buffer
 620  */
 621 const void*
 622 g_buffered_input_stream_peek_buffer (GBufferedInputStream *stream,
 623                                      gsize                *count)
 624 {
 625   GBufferedInputStreamPrivate *priv;
 626
 627   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), NULL);
 628
 629   priv = stream->priv;
 630
 631   if (count)
 632     *count = priv->end - priv->pos;
 633
 634   return priv->buffer + priv->pos;
 635 }
 636
 637 static void
 638 compact_buffer (GBufferedInputStream *stream)
 639 {
 640   GBufferedInputStreamPrivate *priv;
 641   gsize current_size;
 642
 643   priv = stream->priv;
 644
 645   current_size = priv->end - priv->pos;
 646
 647   g_memmove (priv->buffer, priv->buffer + priv->pos, current_size);
 648
 649   priv->pos = 0;
 650   priv->end = current_size;
 651 }
 652
 653 static gssize
 654 g_buffered_input_stream_real_fill (GBufferedInputStream  *stream,
 655                                    gssize                 count,
 656                                    GCancellable          *cancellable,
 657                                    GError               **error)
 658 {
 659   GBufferedInputStreamPrivate *priv;
 660   GInputStream *base_stream;
 661   gssize nread;
 662   gsize in_buffer;
 663
 664   priv = stream->priv;
 665
 666   if (count == -1)
 667     count = priv->len;
 668
 669   in_buffer = priv->end - priv->pos;
 670
 671   /* Never fill more than can fit in the buffer */
 672   count = MIN (count, priv->len - in_buffer);
 673
 674   /* If requested length does not fit at end, compact */
 675   if (priv->len - priv->end < count)
 676     compact_buffer (stream);
 677
 678   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 679   nread = g_input_stream_read (base_stream,
 680                                priv->buffer + priv->end,
 681                                count,
 682                                cancellable,
 683                                error);
 684
 685   if (nread > 0)
 686     priv->end += nread;
 687
 688   return nread;
 689 }
 690
 691 static gssize
 692 g_buffered_input_stream_skip (GInputStream  *stream,
 693                               gsize          count,
 694                               GCancellable  *cancellable,
 695                               GError       **error)
 696 {
 697   GBufferedInputStream        *bstream;
 698   GBufferedInputStreamPrivate *priv;
 699   GBufferedInputStreamClass *class;
 700   GInputStream *base_stream;
 701   gsize available, bytes_skipped;
 702   gssize nread;
 703
 704   bstream = G_BUFFERED_INPUT_STREAM (stream);
 705   priv = bstream->priv;
 706
 707   available = priv->end - priv->pos;
 708
 709   if (count <= available)
 710     {
 711       priv->pos += count;
 712       return count;
 713     }
 714
 715   /* Full request not available, skip all currently available and
 716    * request refill for more
 717    */
 718
 719   priv->pos = 0;
 720   priv->end = 0;
 721   bytes_skipped = available;
 722   count -= available;
 723
 724   if (bytes_skipped > 0)
 725     error = NULL; /* Ignore further errors if we already read some data */
 726
 727   if (count > priv->len)
 728     {
 729       /* Large request, shortcut buffer */
 730
 731       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 732
 733       nread = g_input_stream_skip (base_stream,
 734                                    count,
 735                                    cancellable,
 736                                    error);
 737
 738       if (nread < 0 && bytes_skipped == 0)
 739         return -1;
 740
 741       if (nread > 0)
 742         bytes_skipped += nread;
 743
 744       return bytes_skipped;
 745     }
 746
 747   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 748   nread = class->fill (bstream, priv->len, cancellable, error);
 749
 750   if (nread < 0)
 751     {
 752       if (bytes_skipped == 0)
 753         return -1;
 754       else
 755         return bytes_skipped;
 756     }
 757
 758   available = priv->end - priv->pos;
 759   count = MIN (count, available);
 760
 761   bytes_skipped += count;
 762   priv->pos += count;
 763
 764   return bytes_skipped;
 765 }
 766
 767 static gssize
 768 g_buffered_input_stream_read (GInputStream *stream,
 769                               void         *buffer,
 770                               gsize         count,
 771                               GCancellable *cancellable,
 772                               GError      **error)
 773 {
 774   GBufferedInputStream        *bstream;
 775   GBufferedInputStreamPrivate *priv;
 776   GBufferedInputStreamClass *class;
 777   GInputStream *base_stream;
 778   gsize available, bytes_read;
 779   gssize nread;
 780
 781   bstream = G_BUFFERED_INPUT_STREAM (stream);
 782   priv = bstream->priv;
 783
 784   available = priv->end - priv->pos;
 785
 786   if (count <= available)
 787     {
 788       memcpy (buffer, priv->buffer + priv->pos, count);
 789       priv->pos += count;
 790       return count;
 791     }
 792
 793   /* Full request not available, read all currently available and
 794    * request refill for more
 795    */
 796
 797   memcpy (buffer, priv->buffer + priv->pos, available);
 798   priv->pos = 0;
 799   priv->end = 0;
 800   bytes_read = available;
 801   count -= available;
 802
 803   if (bytes_read > 0)
 804     error = NULL; /* Ignore further errors if we already read some data */
 805
 806   if (count > priv->len)
 807     {
 808       /* Large request, shortcut buffer */
 809
 810       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 811
 812       nread = g_input_stream_read (base_stream,
 813                                    (char *)buffer + bytes_read,
 814                                    count,
 815                                    cancellable,
 816                                    error);
 817
 818       if (nread < 0 && bytes_read == 0)
 819         return -1;
 820
 821       if (nread > 0)
 822         bytes_read += nread;
 823
 824       return bytes_read;
 825     }
 826
 827   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
 828   nread = class->fill (bstream, priv->len, cancellable, error);
 829   if (nread < 0)
 830     {
 831       if (bytes_read == 0)
 832         return -1;
 833       else
 834         return bytes_read;
 835     }
 836
 837   available = priv->end - priv->pos;
 838   count = MIN (count, available);
 839
 840   memcpy ((char *)buffer + bytes_read, (char *)priv->buffer + priv->pos, count);
 841   bytes_read += count;
 842   priv->pos += count;
 843
 844   return bytes_read;
 845 }
 846
 847 static goffset
 848 g_buffered_input_stream_tell (GSeekable *seekable)
 849 {
 850   GBufferedInputStream        *bstream;
 851   GBufferedInputStreamPrivate *priv;
 852   GInputStream *base_stream;
 853   GSeekable    *base_stream_seekable;
 854   gsize available;
 855   goffset base_offset;
 856
 857   bstream = G_BUFFERED_INPUT_STREAM (seekable);
 858   priv = bstream->priv;
 859
 860   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 861   if (!G_IS_SEEKABLE (base_stream))
 862     return 0;
 863   base_stream_seekable = G_SEEKABLE (base_stream);
 864
 865   available = priv->end - priv->pos;
 866   base_offset = g_seekable_tell (base_stream_seekable);
 867
 868   return base_offset - available;
 869 }
 870
 871 static gboolean
 872 g_buffered_input_stream_can_seek (GSeekable *seekable)
 873 {
 874   GInputStream *base_stream;
 875
 876   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 877   return G_IS_SEEKABLE (base_stream) && g_seekable_can_seek (G_SEEKABLE (base_stream));
 878 }
 879
 880 static gboolean
 881 g_buffered_input_stream_seek (GSeekable     *seekable,
 882                               goffset        offset,
 883                               GSeekType      type,
 884                               GCancellable  *cancellable,
 885                               GError       **error)
 886 {
 887   GBufferedInputStream        *bstream;
 888   GBufferedInputStreamPrivate *priv;
 889   GInputStream *base_stream;
 890   GSeekable *base_stream_seekable;
 891
 892   bstream = G_BUFFERED_INPUT_STREAM (seekable);
 893   priv = bstream->priv;
 894
 895   base_stream = G_FILTER_INPUT_STREAM (seekable)->base_stream;
 896   if (!G_IS_SEEKABLE (base_stream))
 897     {
 898       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
 899                            _("Seek not supported on base stream"));
 900       return FALSE;
 901     }
 902
 903   base_stream_seekable = G_SEEKABLE (base_stream);
 904
 905   if (type == G_SEEK_CUR)
 906     {
 907       if (offset <= priv->end - priv->pos && offset >= -priv->pos)
 908         {
 909           priv->pos += offset;
 910           return TRUE;
 911         }
 912       else
 913         {
 914           offset -= priv->end - priv->pos;
 915         }
 916     }
 917
 918   if (g_seekable_seek (base_stream_seekable, offset, type, cancellable, error))
 919     {
 920       priv->pos = 0;
 921       priv->end = 0;
 922       return TRUE;
 923     }
 924   else
 925     {
 926       return FALSE;
 927     }
 928 }
 929
 930 static gboolean
 931 g_buffered_input_stream_can_truncate (GSeekable *seekable)
 932 {
 933   return FALSE;
 934 }
 935
 936 static gboolean
 937 g_buffered_input_stream_truncate (GSeekable     *seekable,
 938                                   goffset        offset,
 939                                   GCancellable  *cancellable,
 940                                   GError       **error)
 941 {
 942   g_set_error_literal (error,
 943                        G_IO_ERROR,
 944                        G_IO_ERROR_NOT_SUPPORTED,
 945                        _("Cannot truncate GBufferedInputStream"));
 946   return FALSE;
 947 }
 948
 949 /**
 950  * g_buffered_input_stream_read_byte:
 951  * @stream: a #GBufferedInputStream
 952  * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 953  * @error: location to store the error occurring, or %NULL to ignore
 954  *
 955  * Tries to read a single byte from the stream or the buffer. Will block
 956  * during this read.
 957  *
 958  * On success, the byte read from the stream is returned. On end of stream
 959  * -1 is returned but it's not an exceptional error and @error is not set.
 960  *
 961  * If @cancellable is not %NULL, then the operation can be cancelled by
 962  * triggering the cancellable object from another thread. If the operation
 963  * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
 964  * operation was partially finished when the operation was cancelled the
 965  * partial result will be returned, without an error.
 966  *
 967  * On error -1 is returned and @error is set accordingly.
 968  *
 969  * Returns: the byte read from the @stream, or -1 on end of stream or error.
 970  */
 971 int
 972 g_buffered_input_stream_read_byte (GBufferedInputStream  *stream,
 973                                    GCancellable          *cancellable,
 974                                    GError               **error)
 975 {
 976   GBufferedInputStreamPrivate *priv;
 977   GBufferedInputStreamClass *class;
 978   GInputStream *input_stream;
 979   gsize available;
 980   gssize nread;
 981
 982   g_return_val_if_fail (G_IS_BUFFERED_INPUT_STREAM (stream), -1);
 983
 984   priv = stream->priv;
 985   input_stream = G_INPUT_STREAM (stream);
 986
 987   if (g_input_stream_is_closed (input_stream))
 988     {
 989       g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
 990                            _("Stream is already closed"));
 991       return -1;
 992     }
 993
 994   if (!g_input_stream_set_pending (input_stream, error))
 995     return -1;
 996
 997   available = priv->end - priv->pos;
 998
 999   if (available != 0)
1000     {
1001       g_input_stream_clear_pending (input_stream);
1002       return priv->buffer[priv->pos++];
1003     }
1004
1005   /* Byte not available, request refill for more */
1006
1007   if (cancellable)
1008     g_cancellable_push_current (cancellable);
1009
1010   priv->pos = 0;
1011   priv->end = 0;
1012
1013   class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
1014   nread = class->fill (stream, priv->len, cancellable, error);
1015
1016   if (cancellable)
1017     g_cancellable_pop_current (cancellable);
1018
1019   g_input_stream_clear_pending (input_stream);
1020
1021   if (nread <= 0)
1022     return -1; /* error or end of stream */
1023
1024   return priv->buffer[priv->pos++];
1025 }
1026
1027 /* ************************** */
1028 /* Async stuff implementation */
1029 /* ************************** */
1030
1031 static void
1032 fill_async_callback (GObject      *source_object,
1033                      GAsyncResult *result,
1034                      gpointer      user_data)
1035 {
1036   GError *error;
1037   gssize res;
1038   GTask *task = user_data;
1039
1040   error = NULL;
1041   res = g_input_stream_read_finish (G_INPUT_STREAM (source_object),
1042                                     result, &error);
1043   if (res == -1)
1044     g_task_return_error (task, error);
1045   else
1046     {
1047       GBufferedInputStream *stream;
1048       GBufferedInputStreamPrivate *priv;
1049
1050       stream = g_task_get_source_object (task);
1051       priv = G_BUFFERED_INPUT_STREAM (stream)->priv;
1052
1053       g_assert_cmpint (priv->end + res, <=, priv->len);
1054       priv->end += res;
1055
1056       g_task_return_int (task, res);
1057     }
1058
1059   g_object_unref (task);
1060 }
1061
1062 static void
1063 g_buffered_input_stream_real_fill_async (GBufferedInputStream *stream,
1064                                          gssize                count,
1065                                          int                   io_priority,
1066                                          GCancellable         *cancellable,
1067                                          GAsyncReadyCallback   callback,
1068                                          gpointer              user_data)
1069 {
1070   GBufferedInputStreamPrivate *priv;
1071   GInputStream *base_stream;
1072   GTask *task;
1073   gsize in_buffer;
1074
1075   priv = stream->priv;
1076
1077   if (count == -1)
1078     count = priv->len;
1079
1080   in_buffer = priv->end - priv->pos;
1081
1082   /* Never fill more than can fit in the buffer */
1083   count = MIN (count, priv->len - in_buffer);
1084
1085   /* If requested length does not fit at end, compact */
1086   if (priv->len - priv->end < count)
1087     compact_buffer (stream);
1088
1089   task = g_task_new (stream, cancellable, callback, user_data);
1090
1091   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
1092   g_input_stream_read_async (base_stream,
1093                              priv->buffer + priv->end,
1094                              count,
1095                              io_priority,
1096                              cancellable,
1097                              fill_async_callback,
1098                              task);
1099 }
1100
1101 static gssize
1102 g_buffered_input_stream_real_fill_finish (GBufferedInputStream *stream,
1103                                           GAsyncResult         *result,
1104                                           GError              **error)
1105 {
1106   g_return_val_if_fail (g_task_is_valid (result, stream), -1);
1107
1108   return g_task_propagate_int (G_TASK (result), error);
1109 }
1110
1111 typedef struct
1112 {
1113   gssize bytes_skipped;
1114   gssize count;
1115 } SkipAsyncData;
1116
1117 static void
1118 free_skip_async_data (gpointer _data)
1119 {
1120   SkipAsyncData *data = _data;
1121   g_slice_free (SkipAsyncData, data);
1122 }
1123
1124 static void
1125 large_skip_callback (GObject      *source_object,
1126                      GAsyncResult *result,
1127                      gpointer      user_data)
1128 {
1129   GTask *task = G_TASK (user_data);
1130   SkipAsyncData *data;
1131   GError *error;
1132   gssize nread;
1133
1134   data = g_task_get_task_data (task);
1135
1136   error = NULL;
1137   nread = g_input_stream_skip_finish (G_INPUT_STREAM (source_object),
1138                                       result, &error);
1139
1140   /* Only report the error if we've not already read some data */
1141   if (nread < 0 && data->bytes_skipped == 0)
1142     g_task_return_error (task, error);
1143   else
1144     {
1145       if (error)
1146         g_error_free (error);
1147
1148       if (nread > 0)
1149         data->bytes_skipped += nread;
1150
1151       g_task_return_int (task, data->bytes_skipped);
1152     }
1153
1154   g_object_unref (task);
1155 }
1156
1157 static void
1158 skip_fill_buffer_callback (GObject      *source_object,
1159                            GAsyncResult *result,
1160                            gpointer      user_data)
1161 {
1162   GTask *task = G_TASK (user_data);
1163   GBufferedInputStream *bstream;
1164   GBufferedInputStreamPrivate *priv;
1165   SkipAsyncData *data;
1166   GError *error;
1167   gssize nread;
1168   gsize available;
1169
1170   bstream = G_BUFFERED_INPUT_STREAM (source_object);
1171   priv = bstream->priv;
1172
1173   data = g_task_get_task_data (task);
1174
1175   error = NULL;
1176   nread = g_buffered_input_stream_fill_finish (bstream,
1177                                                result, &error);
1178
1179   if (nread < 0 && data->bytes_skipped == 0)
1180     g_task_return_error (task, error);
1181   else
1182     {
1183       if (error)
1184         g_error_free (error);
1185
1186       if (nread > 0)
1187         {
1188           available = priv->end - priv->pos;
1189           data->count = MIN (data->count, available);
1190
1191           data->bytes_skipped += data->count;
1192           priv->pos += data->count;
1193         }
1194
1195       g_task_return_int (task, data->bytes_skipped);
1196     }
1197
1198   g_object_unref (task);
1199 }
1200
1201 static void
1202 g_buffered_input_stream_skip_async (GInputStream        *stream,
1203                                     gsize                count,
1204                                     int                  io_priority,
1205                                     GCancellable        *cancellable,
1206                                     GAsyncReadyCallback  callback,
1207                                     gpointer             user_data)
1208 {
1209   GBufferedInputStream *bstream;
1210   GBufferedInputStreamPrivate *priv;
1211   GBufferedInputStreamClass *class;
1212   GInputStream *base_stream;
1213   gsize available;
1214   GTask *task;
1215   SkipAsyncData *data;
1216
1217   bstream = G_BUFFERED_INPUT_STREAM (stream);
1218   priv = bstream->priv;
1219
1220   data = g_slice_new (SkipAsyncData);
1221   data->bytes_skipped = 0;
1222   task = g_task_new (stream, cancellable, callback, user_data);
1223   g_task_set_task_data (task, data, free_skip_async_data);
1224
1225   available = priv->end - priv->pos;
1226
1227   if (count <= available)
1228     {
1229       priv->pos += count;
1230
1231       g_task_return_int (task, count);
1232       g_object_unref (task);
1233       return;
1234     }
1235
1236   /* Full request not available, skip all currently available
1237    * and request refill for more
1238    */
1239
1240   priv->pos = 0;
1241   priv->end = 0;
1242
1243   count -= available;
1244
1245   data->bytes_skipped = available;
1246   data->count = count;
1247
1248   if (count > priv->len)
1249     {
1250       /* Large request, shortcut buffer */
1251
1252       base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
1253
1254       g_input_stream_skip_async (base_stream,
1255                                  count,
1256                                  io_priority, cancellable,
1257                                  large_skip_callback,
1258                                  task);
1259     }
1260   else
1261     {
1262       class = G_BUFFERED_INPUT_STREAM_GET_CLASS (stream);
1263       class->fill_async (bstream, priv->len, io_priority, cancellable,
1264                          skip_fill_buffer_callback, task);
1265     }
1266 }
1267
1268 static gssize
1269 g_buffered_input_stream_skip_finish (GInputStream   *stream,
1270                                      GAsyncResult   *result,
1271                                      GError        **error)
1272 {
1273   g_return_val_if_fail (g_task_is_valid (result, stream), -1);
1274
1275   return g_task_propagate_int (G_TASK (result), error);
1276 }