gio/gconverterinputstream.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2009 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: Alexander Larsson <alexl@redhat.com>
  21  */
  22
  23 #include "config.h"
  24
  25 #include <string.h>
  26
  27 #include "gconverterinputstream.h"
  28 #include "gpollableinputstream.h"
  29 #include "gsimpleasyncresult.h"
  30 #include "gcancellable.h"
  31 #include "gioenumtypes.h"
  32 #include "gioerror.h"
  33 #include "glibintl.h"
  34
  35
  36 /**
  37  * SECTION:gconverterinputstream
  38  * @short_description: Converter Input Stream
  39  * @include: gio/gio.h
  40  * @see_also: #GInputStream, #GConverter
  41  *
  42  * Converter input stream implements #GInputStream and allows
  43  * conversion of data of various types during reading.
  44  *
  45  * As of GLib 2.34, #GConverterInputStream implements
  46  * #GPollableInputStream.
  47  **/
  48
  49 #define INITIAL_BUFFER_SIZE 4096
  50
  51 typedef struct {
  52   char *data;
  53   gsize start;
  54   gsize end;
  55   gsize size;
  56 } Buffer;
  57
  58 struct _GConverterInputStreamPrivate {
  59   gboolean at_input_end;
  60   gboolean finished;
  61   gboolean need_input;
  62   GConverter *converter;
  63   Buffer input_buffer;
  64   Buffer converted_buffer;
  65 };
  66
  67 enum {
  68   PROP_0,
  69   PROP_CONVERTER
  70 };
  71
  72 static void   g_converter_input_stream_set_property (GObject       *object,
  73                                                      guint          prop_id,
  74                                                      const GValue  *value,
  75                                                      GParamSpec    *pspec);
  76 static void   g_converter_input_stream_get_property (GObject       *object,
  77                                                      guint          prop_id,
  78                                                      GValue        *value,
  79                                                      GParamSpec    *pspec);
  80 static void   g_converter_input_stream_finalize     (GObject       *object);
  81 static gssize g_converter_input_stream_read         (GInputStream  *stream,
  82                                                      void          *buffer,
  83                                                      gsize          count,
  84                                                      GCancellable  *cancellable,
  85                                                      GError       **error);
  86
  87 static gboolean g_converter_input_stream_can_poll         (GPollableInputStream *stream);
  88 static gboolean g_converter_input_stream_is_readable      (GPollableInputStream *stream);
  89 static gssize   g_converter_input_stream_read_nonblocking (GPollableInputStream  *stream,
  90                                                            void                  *buffer,
  91                                                            gsize                  size,
  92                                                            GError               **error);
  93
  94 static GSource *g_converter_input_stream_create_source    (GPollableInputStream *stream,
  95                                                            GCancellable          *cancellable);
  96
  97 static void g_converter_input_stream_pollable_iface_init  (GPollableInputStreamInterface *iface);
  98
  99 G_DEFINE_TYPE_WITH_CODE (GConverterInputStream,
 100                          g_converter_input_stream,
 101                          G_TYPE_FILTER_INPUT_STREAM,
 102                          G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,
 103                                                 g_converter_input_stream_pollable_iface_init);
 104                          )
 105
 106 static void
 107 g_converter_input_stream_class_init (GConverterInputStreamClass *klass)
 108 {
 109   GObjectClass *object_class;
 110   GInputStreamClass *istream_class;
 111
 112   g_type_class_add_private (klass, sizeof (GConverterInputStreamPrivate));
 113
 114   object_class = G_OBJECT_CLASS (klass);
 115   object_class->get_property = g_converter_input_stream_get_property;
 116   object_class->set_property = g_converter_input_stream_set_property;
 117   object_class->finalize     = g_converter_input_stream_finalize;
 118
 119   istream_class = G_INPUT_STREAM_CLASS (klass);
 120   istream_class->read_fn = g_converter_input_stream_read;
 121
 122   g_object_class_install_property (object_class,
 123                                    PROP_CONVERTER,
 124                                    g_param_spec_object ("converter",
 125                                                         P_("Converter"),
 126                                                         P_("The converter object"),
 127                                                         G_TYPE_CONVERTER,
 128                                                         G_PARAM_READWRITE|
 129                                                         G_PARAM_CONSTRUCT_ONLY|
 130                                                         G_PARAM_STATIC_STRINGS));
 131
 132 }
 133
 134 static void
 135 g_converter_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)
 136 {
 137   iface->can_poll = g_converter_input_stream_can_poll;
 138   iface->is_readable = g_converter_input_stream_is_readable;
 139   iface->read_nonblocking = g_converter_input_stream_read_nonblocking;
 140   iface->create_source = g_converter_input_stream_create_source;
 141 }
 142
 143 static void
 144 g_converter_input_stream_finalize (GObject *object)
 145 {
 146   GConverterInputStreamPrivate *priv;
 147   GConverterInputStream        *stream;
 148
 149   stream = G_CONVERTER_INPUT_STREAM (object);
 150   priv = stream->priv;
 151
 152   g_free (priv->input_buffer.data);
 153   g_free (priv->converted_buffer.data);
 154   if (priv->converter)
 155     g_object_unref (priv->converter);
 156
 157   G_OBJECT_CLASS (g_converter_input_stream_parent_class)->finalize (object);
 158 }
 159
 160 static void
 161 g_converter_input_stream_set_property (GObject      *object,
 162                                        guint         prop_id,
 163                                        const GValue *value,
 164                                        GParamSpec   *pspec)
 165 {
 166   GConverterInputStream *cstream;
 167
 168   cstream = G_CONVERTER_INPUT_STREAM (object);
 169
 170    switch (prop_id)
 171     {
 172     case PROP_CONVERTER:
 173       cstream->priv->converter = g_value_dup_object (value);
 174       break;
 175
 176     default:
 177       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 178       break;
 179     }
 180
 181 }
 182
 183 static void
 184 g_converter_input_stream_get_property (GObject    *object,
 185                                        guint       prop_id,
 186                                        GValue     *value,
 187                                        GParamSpec *pspec)
 188 {
 189   GConverterInputStreamPrivate *priv;
 190   GConverterInputStream        *cstream;
 191
 192   cstream = G_CONVERTER_INPUT_STREAM (object);
 193   priv = cstream->priv;
 194
 195   switch (prop_id)
 196     {
 197     case PROP_CONVERTER:
 198       g_value_set_object (value, priv->converter);
 199       break;
 200
 201     default:
 202       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 203       break;
 204     }
 205
 206 }
 207 static void
 208 g_converter_input_stream_init (GConverterInputStream *stream)
 209 {
 210   stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
 211                                               G_TYPE_CONVERTER_INPUT_STREAM,
 212                                               GConverterInputStreamPrivate);
 213 }
 214
 215 /**
 216  * g_converter_input_stream_new:
 217  * @base_stream: a #GInputStream
 218  * @converter: a #GConverter
 219  *
 220  * Creates a new converter input stream for the @base_stream.
 221  *
 222  * Returns: a new #GInputStream.
 223  **/
 224 GInputStream *
 225 g_converter_input_stream_new (GInputStream *base_stream,
 226                               GConverter   *converter)
 227 {
 228   GInputStream *stream;
 229
 230   g_return_val_if_fail (G_IS_INPUT_STREAM (base_stream), NULL);
 231
 232   stream = g_object_new (G_TYPE_CONVERTER_INPUT_STREAM,
 233                          "base-stream", base_stream,
 234                          "converter", converter,
 235                          NULL);
 236
 237   return stream;
 238 }
 239
 240 static gsize
 241 buffer_data_size (Buffer *buffer)
 242 {
 243   return buffer->end - buffer->start;
 244 }
 245
 246 static gsize
 247 buffer_tailspace (Buffer *buffer)
 248 {
 249   return buffer->size - buffer->end;
 250 }
 251
 252 static char *
 253 buffer_data (Buffer *buffer)
 254 {
 255   return buffer->data + buffer->start;
 256 }
 257
 258 static void
 259 buffer_consumed (Buffer *buffer,
 260                  gsize count)
 261 {
 262   buffer->start += count;
 263   if (buffer->start == buffer->end)
 264     buffer->start = buffer->end = 0;
 265 }
 266
 267 static void
 268 buffer_read (Buffer *buffer,
 269              char *dest,
 270              gsize count)
 271 {
 272   memcpy (dest, buffer->data + buffer->start, count);
 273   buffer_consumed (buffer, count);
 274 }
 275
 276 static void
 277 compact_buffer (Buffer *buffer)
 278 {
 279   gsize in_buffer;
 280
 281   in_buffer = buffer_data_size (buffer);
 282   memmove (buffer->data,
 283            buffer->data + buffer->start,
 284            in_buffer);
 285   buffer->end -= buffer->start;
 286   buffer->start = 0;
 287 }
 288
 289 static void
 290 grow_buffer (Buffer *buffer)
 291 {
 292   char *data;
 293   gsize size, in_buffer;
 294
 295   if (buffer->size == 0)
 296     size = INITIAL_BUFFER_SIZE;
 297   else
 298     size = buffer->size * 2;
 299
 300   data = g_malloc (size);
 301   in_buffer = buffer_data_size (buffer);
 302
 303   memcpy (data,
 304           buffer->data + buffer->start,
 305           in_buffer);
 306   g_free (buffer->data);
 307   buffer->data = data;
 308   buffer->end -= buffer->start;
 309   buffer->start = 0;
 310   buffer->size = size;
 311 }
 312
 313 /* Ensures that the buffer can fit at_least_size bytes,
 314  * *including* the current in-buffer data */
 315 static void
 316 buffer_ensure_space (Buffer *buffer,
 317                      gsize at_least_size)
 318 {
 319   gsize in_buffer, left_to_fill;
 320
 321   in_buffer = buffer_data_size (buffer);
 322
 323   if (in_buffer >= at_least_size)
 324     return;
 325
 326   left_to_fill = buffer_tailspace (buffer);
 327
 328   if (in_buffer + left_to_fill >= at_least_size)
 329     {
 330       /* We fit in remaining space at end */
 331       /* If the copy is small, compact now anyway so we can fill more */
 332       if (in_buffer < 256)
 333         compact_buffer (buffer);
 334     }
 335   else if (buffer->size >= at_least_size)
 336     {
 337       /* We fit, but only if we compact */
 338       compact_buffer (buffer);
 339     }
 340   else
 341     {
 342       /* Need to grow buffer */
 343       while (buffer->size < at_least_size)
 344         grow_buffer (buffer);
 345     }
 346 }
 347
 348 static gssize
 349 fill_input_buffer (GConverterInputStream  *stream,
 350                    gsize                   at_least_size,
 351                    gboolean                blocking,
 352                    GCancellable           *cancellable,
 353                    GError                **error)
 354 {
 355   GConverterInputStreamPrivate *priv;
 356   GInputStream *base_stream;
 357   gssize nread;
 358
 359   priv = stream->priv;
 360
 361   buffer_ensure_space (&priv->input_buffer, at_least_size);
 362
 363   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 364   nread = g_pollable_stream_read (base_stream,
 365                                   priv->input_buffer.data + priv->input_buffer.end,
 366                                   buffer_tailspace (&priv->input_buffer),
 367                                   blocking,
 368                                   cancellable,
 369                                   error);
 370
 371   if (nread > 0)
 372     {
 373       priv->input_buffer.end += nread;
 374       priv->need_input = FALSE;
 375     }
 376
 377   return nread;
 378 }
 379
 380
 381 static gssize
 382 read_internal (GInputStream *stream,
 383                void         *buffer,
 384                gsize         count,
 385                gboolean      blocking,
 386                GCancellable *cancellable,
 387                GError      **error)
 388 {
 389   GConverterInputStream *cstream;
 390   GConverterInputStreamPrivate *priv;
 391   gsize available, total_bytes_read;
 392   gssize nread;
 393   GConverterResult res;
 394   gsize bytes_read;
 395   gsize bytes_written;
 396   GError *my_error;
 397   GError *my_error2;
 398
 399   cstream = G_CONVERTER_INPUT_STREAM (stream);
 400   priv = cstream->priv;
 401
 402   available = buffer_data_size (&priv->converted_buffer);
 403
 404   if (available > 0 &&
 405       count <= available)
 406     {
 407       /* Converted data available, return that */
 408       buffer_read (&priv->converted_buffer, buffer, count);
 409       return count;
 410     }
 411
 412   /* Full request not available, read all currently available and request
 413      refill/conversion for more */
 414
 415   buffer_read (&priv->converted_buffer, buffer, available);
 416
 417   total_bytes_read = available;
 418   count -= available;
 419
 420   /* If there is no data to convert, and no pre-converted data,
 421      do some i/o for more input */
 422   if (buffer_data_size (&priv->input_buffer) == 0 &&
 423       total_bytes_read == 0 &&
 424       !priv->at_input_end)
 425     {
 426       nread = fill_input_buffer (cstream, count, blocking, cancellable, error);
 427       if (nread < 0)
 428         return -1;
 429       if (nread == 0)
 430         priv->at_input_end = TRUE;
 431     }
 432
 433   /* First try to convert any available data (or state) directly to the user buffer: */
 434   if (!priv->finished)
 435     {
 436       my_error = NULL;
 437       res = g_converter_convert (priv->converter,
 438                                  buffer_data (&priv->input_buffer),
 439                                  buffer_data_size (&priv->input_buffer),
 440                                  buffer, count,
 441                                  priv->at_input_end ? G_CONVERTER_INPUT_AT_END : 0,
 442                                  &bytes_read,
 443                                  &bytes_written,
 444                                  &my_error);
 445       if (res != G_CONVERTER_ERROR)
 446         {
 447           total_bytes_read += bytes_written;
 448           buffer_consumed (&priv->input_buffer, bytes_read);
 449           if (res == G_CONVERTER_FINISHED)
 450             priv->finished = TRUE; /* We're done converting */
 451         }
 452       else if (total_bytes_read == 0 &&
 453                !g_error_matches (my_error,
 454                                  G_IO_ERROR,
 455                                  G_IO_ERROR_PARTIAL_INPUT) &&
 456                !g_error_matches (my_error,
 457                                  G_IO_ERROR,
 458                                  G_IO_ERROR_NO_SPACE))
 459         {
 460           /* No previously read data and no "special" error, return error */
 461           g_propagate_error (error, my_error);
 462           return -1;
 463         }
 464       else
 465         g_error_free (my_error);
 466     }
 467
 468   /* We had some pre-converted data and/or we converted directly to the
 469      user buffer */
 470   if (total_bytes_read > 0)
 471     return total_bytes_read;
 472
 473   /* If there is no more to convert, return EOF */
 474   if (priv->finished)
 475     {
 476       g_assert (buffer_data_size (&priv->converted_buffer) == 0);
 477       return 0;
 478     }
 479
 480   /* There was "complexity" in the straight-to-buffer conversion,
 481    * convert to our own buffer and write from that.
 482    * At this point we didn't produce any data into @buffer.
 483    */
 484
 485   /* Ensure we have *some* initial target space */
 486   buffer_ensure_space (&priv->converted_buffer, count);
 487
 488   while (TRUE)
 489     {
 490       g_assert (!priv->finished);
 491
 492       /* Try to convert to our buffer */
 493       my_error = NULL;
 494       res = g_converter_convert (priv->converter,
 495                                  buffer_data (&priv->input_buffer),
 496                                  buffer_data_size (&priv->input_buffer),
 497                                  buffer_data (&priv->converted_buffer),
 498                                  buffer_tailspace (&priv->converted_buffer),
 499                                  priv->at_input_end ? G_CONVERTER_INPUT_AT_END : 0,
 500                                  &bytes_read,
 501                                  &bytes_written,
 502                                  &my_error);
 503       if (res != G_CONVERTER_ERROR)
 504         {
 505           priv->converted_buffer.end += bytes_written;
 506           buffer_consumed (&priv->input_buffer, bytes_read);
 507
 508           /* Maybe we consumed without producing any output */
 509           if (buffer_data_size (&priv->converted_buffer) == 0 && res != G_CONVERTER_FINISHED)
 510             continue; /* Convert more */
 511
 512           if (res == G_CONVERTER_FINISHED)
 513             priv->finished = TRUE;
 514
 515           total_bytes_read = MIN (count, buffer_data_size (&priv->converted_buffer));
 516           buffer_read (&priv->converted_buffer, buffer, total_bytes_read);
 517
 518           g_assert (priv->finished || total_bytes_read > 0);
 519
 520           return total_bytes_read;
 521         }
 522
 523       /* There was some kind of error filling our buffer */
 524
 525       if (g_error_matches (my_error,
 526                            G_IO_ERROR,
 527                            G_IO_ERROR_PARTIAL_INPUT) &&
 528           !priv->at_input_end)
 529         {
 530           /* Need more data */
 531           my_error2 = NULL;
 532           nread = fill_input_buffer (cstream,
 533                                      buffer_data_size (&priv->input_buffer) + 4096,
 534                                      blocking,
 535                                      cancellable,
 536                                      &my_error2);
 537           if (nread < 0)
 538             {
 539               /* Can't read any more data, return that error */
 540               g_error_free (my_error);
 541               g_propagate_error (error, my_error2);
 542               priv->need_input = TRUE;
 543               return -1;
 544             }
 545           else if (nread == 0)
 546             {
 547               /* End of file, try INPUT_AT_END */
 548               priv->at_input_end = TRUE;
 549             }
 550           g_error_free (my_error);
 551           continue;
 552         }
 553
 554       if (g_error_matches (my_error,
 555                            G_IO_ERROR,
 556                            G_IO_ERROR_NO_SPACE))
 557         {
 558           /* Need more destination space, grow it
 559            * Note: if we actually grow the buffer (as opposed to compacting it),
 560            * this will double the size, not just add one byte. */
 561           buffer_ensure_space (&priv->converted_buffer,
 562                                priv->converted_buffer.size + 1);
 563           g_error_free (my_error);
 564           continue;
 565         }
 566
 567       /* Any other random error, return it */
 568       g_propagate_error (error, my_error);
 569       return -1;
 570     }
 571
 572   g_assert_not_reached ();
 573 }
 574
 575 static gssize
 576 g_converter_input_stream_read (GInputStream *stream,
 577                                void         *buffer,
 578                                gsize         count,
 579                                GCancellable *cancellable,
 580                                GError      **error)
 581 {
 582   return read_internal (stream, buffer, count, TRUE, cancellable, error);
 583 }
 584
 585 static gboolean
 586 g_converter_input_stream_can_poll (GPollableInputStream *stream)
 587 {
 588   GInputStream *base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 589
 590   return (G_IS_POLLABLE_INPUT_STREAM (base_stream) &&
 591           g_pollable_input_stream_can_poll (G_POLLABLE_INPUT_STREAM (base_stream)));
 592 }
 593
 594 static gboolean
 595 g_converter_input_stream_is_readable (GPollableInputStream *stream)
 596 {
 597   GInputStream *base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 598   GConverterInputStream *cstream = G_CONVERTER_INPUT_STREAM (stream);
 599
 600   if (buffer_data_size (&cstream->priv->converted_buffer))
 601     return TRUE;
 602   else if (buffer_data_size (&cstream->priv->input_buffer) &&
 603            !cstream->priv->need_input)
 604     return TRUE;
 605   else
 606     return g_pollable_input_stream_is_readable (G_POLLABLE_INPUT_STREAM (base_stream));
 607 }
 608
 609 static gssize
 610 g_converter_input_stream_read_nonblocking (GPollableInputStream  *stream,
 611                                            void                  *buffer,
 612                                            gsize                  count,
 613                                            GError               **error)
 614 {
 615   return read_internal (G_INPUT_STREAM (stream), buffer, count,
 616                         FALSE, NULL, error);
 617 }
 618
 619 static GSource *
 620 g_converter_input_stream_create_source (GPollableInputStream *stream,
 621                                         GCancellable         *cancellable)
 622 {
 623   GInputStream *base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 624   GSource *base_source, *pollable_source;
 625
 626   if (g_pollable_input_stream_is_readable (stream))
 627     base_source = g_timeout_source_new (0);
 628   else
 629     base_source = g_pollable_input_stream_create_source (G_POLLABLE_INPUT_STREAM (base_stream), NULL);
 630
 631   pollable_source = g_pollable_source_new_full (stream, base_source,
 632                                                 cancellable);
 633   g_source_unref (base_source);
 634
 635   return pollable_source;
 636 }
 637
 638
 639 /**
 640  * g_converter_input_stream_get_converter:
 641  * @converter_stream: a #GConverterInputStream
 642  *
 643  * Gets the #GConverter that is used by @converter_stream.
 644  *
 645  * Returns: (transfer none): the converter of the converter input stream
 646  *
 647  * Since: 2.24
 648  */
 649 GConverter *
 650 g_converter_input_stream_get_converter (GConverterInputStream *converter_stream)
 651 {
 652   return converter_stream->priv->converter;
 653 }