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