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  *
 192  * Creates a new converter input stream for the @base_stream.
 193  *
 194  * Returns: a new #GConverterInputStream.
 195  **/
 196 GConverterInputStream *
 197 g_converter_input_stream_new (GInputStream *base_stream,
 198                               GConverter *converter)
 199 {
 200   GConverterInputStream *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_available (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_available (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_available (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 static void
 286 buffer_ensure_space (Buffer *buffer,
 287                      gsize at_least_size)
 288 {
 289   gsize in_buffer, left_to_fill;
 290
 291   in_buffer = buffer_available (buffer);
 292
 293   if (in_buffer >= at_least_size)
 294     return;
 295
 296   left_to_fill = buffer_tailspace (buffer);
 297
 298   if (in_buffer + left_to_fill >= at_least_size)
 299     {
 300       /* We fit in remaining space at end */
 301       /* If the copy is small, compact now anyway so we can fill more */
 302       if (in_buffer < 256)
 303         compact_buffer (buffer);
 304     }
 305   else if (buffer->size >= at_least_size)
 306     {
 307       /* We fit, but only if we compact */
 308       compact_buffer (buffer);
 309     }
 310   else
 311     {
 312       /* Need to grow buffer */
 313       while (buffer->size < at_least_size)
 314         grow_buffer (buffer);
 315     }
 316 }
 317
 318 static gssize
 319 fill_input_buffer (GConverterInputStream  *stream,
 320                    gsize                   at_least_size,
 321                    GCancellable           *cancellable,
 322                    GError                **error)
 323 {
 324   GConverterInputStreamPrivate *priv;
 325   GInputStream *base_stream;
 326   gssize nread;
 327
 328   priv = stream->priv;
 329
 330   buffer_ensure_space (&priv->input_buffer, at_least_size);
 331
 332   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
 333   nread = g_input_stream_read (base_stream,
 334                                priv->input_buffer.data + priv->input_buffer.end,
 335                                buffer_tailspace (&priv->input_buffer),
 336                                cancellable,
 337                                error);
 338
 339   if (nread > 0)
 340     priv->input_buffer.end += nread;
 341
 342   return nread;
 343 }
 344
 345
 346 static gssize
 347 g_converter_input_stream_read (GInputStream *stream,
 348                                void         *buffer,
 349                                gsize         count,
 350                                GCancellable *cancellable,
 351                                GError      **error)
 352 {
 353   GConverterInputStream *cstream;
 354   GConverterInputStreamPrivate *priv;
 355   gsize available, total_bytes_read;
 356   gssize nread;
 357   GConverterResult res;
 358   gsize bytes_read;
 359   gsize bytes_written;
 360   GError *my_error;
 361   GError *my_error2;
 362
 363   cstream = G_CONVERTER_INPUT_STREAM (stream);
 364   priv = cstream->priv;
 365
 366   available = buffer_available (&priv->converted_buffer);
 367
 368   if (available > 0 &&
 369       count <= available)
 370     {
 371       /* Converted data available, return that */
 372       buffer_read (&priv->converted_buffer, buffer, count);
 373       return count;
 374     }
 375
 376   /* Full request not available, read all currently available and request
 377      refill/conversion for more */
 378
 379   buffer_read (&priv->converted_buffer, buffer, available);
 380
 381   total_bytes_read = available;
 382   count -= available;
 383
 384   /* If there is no data to convert, and no pre-converted data,
 385      do some i/o for more input */
 386   if (buffer_available (&priv->input_buffer) == 0 &&
 387       total_bytes_read == 0 &&
 388       !priv->at_input_end)
 389     {
 390       nread = fill_input_buffer (cstream, count, cancellable, error);
 391       if (nread < 0)
 392         return -1;
 393       if (nread == 0)
 394         priv->at_input_end = TRUE;
 395     }
 396
 397   /* First try to convert any available data (or state) directly to the user buffer: */
 398   if (!priv->finished)
 399     {
 400       my_error = NULL;
 401       res = g_converter_convert (priv->converter,
 402                                  buffer_data (&priv->input_buffer),
 403                                  buffer_available (&priv->input_buffer),
 404                                  buffer, count,
 405                                  priv->at_input_end ? G_CONVERTER_INPUT_AT_END : 0,
 406                                  &bytes_read,
 407                                  &bytes_written,
 408                                  &my_error);
 409       if (res != G_CONVERTER_ERROR)
 410         {
 411           total_bytes_read += bytes_written;
 412           buffer_consumed (&priv->input_buffer, bytes_read);
 413           if (res == G_CONVERTER_FINISHED)
 414             priv->finished = TRUE; /* We're done converting */
 415         }
 416       else if (total_bytes_read == 0 &&
 417                !g_error_matches (my_error,
 418                                  G_IO_ERROR,
 419                                  G_IO_ERROR_PARTIAL_INPUT) &&
 420                !g_error_matches (my_error,
 421                                  G_IO_ERROR,
 422                                  G_IO_ERROR_NO_SPACE))
 423         {
 424           /* No previously read data and no "special" error, return error */
 425           g_propagate_error (error, my_error);
 426           return -1;
 427         }
 428       else
 429         g_error_free (my_error);
 430     }
 431
 432   /* We had some pre-converted data and/or we converted directly to the
 433      user buffer */
 434   if (total_bytes_read > 0)
 435     return total_bytes_read;
 436
 437   /* If there is no more to convert, return EOF */
 438   if (priv->finished)
 439     {
 440       g_assert (buffer_available (&priv->converted_buffer) == 0);
 441       return 0;
 442     }
 443
 444   /* There was "complexity" in the straight-to-buffer conversion,
 445    * convert to our own buffer and write from that.
 446    * At this point we didn't produce any data into @buffer.
 447    */
 448
 449   /* Ensure we have *some* initial target space */
 450   buffer_ensure_space (&priv->converted_buffer, count);
 451
 452   while (TRUE)
 453     {
 454       g_assert (!priv->finished);
 455
 456       /* Try to convert to our buffer */
 457       my_error = NULL;
 458       res = g_converter_convert (priv->converter,
 459                                  buffer_data (&priv->input_buffer),
 460                                  buffer_available (&priv->input_buffer),
 461                                  buffer_data (&priv->converted_buffer),
 462                                  buffer_tailspace (&priv->converted_buffer),
 463                                  priv->at_input_end ? G_CONVERTER_INPUT_AT_END : 0,
 464                                  &bytes_read,
 465                                  &bytes_written,
 466                                  &my_error);
 467       if (res != G_CONVERTER_ERROR)
 468         {
 469           priv->converted_buffer.end += bytes_written;
 470           buffer_consumed (&priv->input_buffer, bytes_read);
 471
 472           /* Maybe we consumed without producing any output */
 473           if (buffer_available (&priv->converted_buffer) == 0 && res != G_CONVERTER_FINISHED)
 474             continue; /* Convert more */
 475
 476           if (res == G_CONVERTER_FINISHED)
 477             priv->finished = TRUE;
 478
 479           total_bytes_read = MIN (count, buffer_available (&priv->converted_buffer));
 480           buffer_read (&priv->converted_buffer, buffer, total_bytes_read);
 481
 482           g_assert (priv->finished || total_bytes_read > 0);
 483
 484           return total_bytes_read;
 485         }
 486
 487       /* There was some kind of error filling our buffer */
 488
 489       if (g_error_matches (my_error,
 490                            G_IO_ERROR,
 491                            G_IO_ERROR_PARTIAL_INPUT) &&
 492           !priv->at_input_end)
 493         {
 494           /* Need more data */
 495           my_error2 = NULL;
 496           res = fill_input_buffer (cstream,
 497                                    buffer_available (&priv->input_buffer) + 4096,
 498                                    cancellable,
 499                                    &my_error2);
 500           if (res < 0)
 501             {
 502               /* Can't read any more data, return that error */
 503               g_error_free (my_error);
 504               g_propagate_error (error, my_error2);
 505               return -1;
 506             }
 507           else if (res == 0)
 508             {
 509               /* End of file, try INPUT_AT_END */
 510               priv->at_input_end = TRUE;
 511             }
 512           g_error_free (my_error);
 513           continue;
 514         }
 515
 516       if (g_error_matches (my_error,
 517                            G_IO_ERROR,
 518                            G_IO_ERROR_NO_SPACE))
 519         {
 520           /* Need more destination space, grow it
 521            * Note: if we actually grow the buffer (as opposed to compacting it),
 522            * this will double the size, not just add one byte. */
 523           buffer_ensure_space (&priv->converted_buffer,
 524                                priv->converted_buffer.size + 1);
 525           g_error_free (my_error);
 526           continue;
 527         }
 528
 529       /* Any other random error, return it */
 530       g_propagate_error (error, my_error);
 531       return -1;
 532     }
 533
 534   g_assert_not_reached ();
 535 }
 536
 537 GConverter *
 538 g_converter_input_stream_get_converter (GConverterInputStream *converter_stream)
 539 {
 540   return converter_stream->priv->converter;
 541 }
 542
 543 #define __G_CONVERTER_INPUT_STREAM_C__
 544 #include "gioaliasdef.c"