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