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