camel/camel-stream-mem.c

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
   2 /* camel-stream-mem.c: memory buffer based stream */
   3
   4 /*
   5  * Authors: Bertrand Guiheneuf <bertrand@helixcode.com>
   6  *          Michael Zucchi <notzed@ximian.com>
   7  *
   8  * Copyright 1999, 2000 Ximian, Inc. (www.ximian.com)
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of version 2 of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
  22  * USA
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include <config.h>
  27 #endif
  28
  29 #include <errno.h>
  30 #include <fcntl.h>
  31 #include <string.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34
  35 #include "camel-stream-mem.h"
  36
  37 static CamelSeekableStreamClass *parent_class = NULL;
  38
  39 /* Returns the class for a CamelStreamMem */
  40 #define CSM_CLASS(so) CAMEL_STREAM_MEM_CLASS(CAMEL_OBJECT_GET_CLASS(so))
  41
  42 static ssize_t stream_read (CamelStream *stream, char *buffer, size_t n);
  43 static ssize_t stream_write (CamelStream *stream, const char *buffer, size_t n);
  44 static gboolean stream_eos (CamelStream *stream);
  45 static off_t stream_seek (CamelSeekableStream *stream, off_t offset,
  46                           CamelStreamSeekPolicy policy);
  47
  48 static void camel_stream_mem_finalize (CamelObject *object);
  49
  50 static void
  51 camel_stream_mem_class_init (CamelStreamMemClass *camel_stream_mem_class)
  52 {
  53         CamelSeekableStreamClass *camel_seekable_stream_class =
  54                 CAMEL_SEEKABLE_STREAM_CLASS (camel_stream_mem_class);
  55         CamelStreamClass *camel_stream_class =
  56                 CAMEL_STREAM_CLASS (camel_stream_mem_class);
  57
  58         parent_class = CAMEL_SEEKABLE_STREAM_CLASS( camel_type_get_global_classfuncs( CAMEL_SEEKABLE_STREAM_TYPE ) );
  59
  60         /* virtual method overload */
  61         camel_stream_class->read = stream_read;
  62         camel_stream_class->write = stream_write;
  63         camel_stream_class->eos = stream_eos;
  64
  65         camel_seekable_stream_class->seek = stream_seek;
  66 }
  67
  68 static void
  69 camel_stream_mem_init (CamelObject *object)
  70 {
  71         CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (object);
  72
  73         stream_mem->owner = FALSE;
  74         stream_mem->buffer = 0;
  75 }
  76
  77 /* could probably be a util method */
  78 static void clear_mem(void *p, size_t len)
  79 {
  80         char *s = p;
  81
  82         /* This also helps debug bad access memory errors */
  83         while (len > 4) {
  84                 *s++ = 0xAB;
  85                 *s++ = 0xAD;
  86                 *s++ = 0xF0;
  87                 *s++ = 0x0D;
  88                 len -= 4;
  89         }
  90
  91         memset(s, 0xbf, len);
  92 }
  93
  94 CamelType
  95 camel_stream_mem_get_type (void)
  96 {
  97         static CamelType camel_stream_mem_type = CAMEL_INVALID_TYPE;
  98
  99         if (camel_stream_mem_type == CAMEL_INVALID_TYPE) {
 100                 camel_stream_mem_type = camel_type_register( CAMEL_SEEKABLE_STREAM_TYPE,
 101                                                              "CamelStreamMem",
 102                                                              sizeof( CamelStreamMem ),
 103                                                              sizeof( CamelStreamMemClass ),
 104                                                              (CamelObjectClassInitFunc) camel_stream_mem_class_init,
 105                                                              NULL,
 106                                                              (CamelObjectInitFunc) camel_stream_mem_init,
 107                                                              (CamelObjectFinalizeFunc) camel_stream_mem_finalize );
 108         }
 109
 110         return camel_stream_mem_type;
 111 }
 112
 113
 114 /**
 115  * camel_stream_mem_new:
 116  *
 117  * Create a new #CamelStreamMem object.
 118  *
 119  * Returns a new #CamelStreamMem
 120  **/
 121 CamelStream *
 122 camel_stream_mem_new (void)
 123 {
 124         return camel_stream_mem_new_with_byte_array (g_byte_array_new ());
 125 }
 126
 127
 128 /**
 129  * camel_stream_mem_new_with_buffer:
 130  * @buffer: a memory buffer to use as the stream data
 131  * @len: length of @buffer
 132  *
 133  * Create a new memory stream using @buffer as the stream data.
 134  *
 135  * Note: @buffer will be copied into an internal #GByteArray structure
 136  * for use as the stream backing. This may have resource implications
 137  * you may wish to consider.
 138  *
 139  * Returns a new #CamelStreamMem
 140  **/
 141 CamelStream *
 142 camel_stream_mem_new_with_buffer (const char *buffer, size_t len)
 143 {
 144         GByteArray *ba;
 145
 146         ba = g_byte_array_new ();
 147         g_byte_array_append (ba, (const guint8 *)buffer, len);
 148         return camel_stream_mem_new_with_byte_array (ba);
 149 }
 150
 151
 152 /**
 153  * camel_stream_mem_new_with_byte_array:
 154  * @buffer: a #GByteArray to use as the stream data
 155  *
 156  * Create a new #CamelStreamMem using @buffer as the stream data.
 157  *
 158  * Note: The newly created #CamelStreamMem will destroy @buffer
 159  * when destroyed.
 160  *
 161  * Returns a new #CamelStreamMem
 162  **/
 163 CamelStream *
 164 camel_stream_mem_new_with_byte_array (GByteArray *buffer)
 165 {
 166         CamelStreamMem *stream_mem;
 167
 168         stream_mem = CAMEL_STREAM_MEM (camel_object_new (CAMEL_STREAM_MEM_TYPE));
 169         stream_mem->buffer = buffer;
 170         stream_mem->owner = TRUE;
 171
 172         return CAMEL_STREAM (stream_mem);
 173 }
 174
 175
 176 /**
 177  * camel_stream_mem_set_secure:
 178  * @mem: a #CamelStreamMem object
 179  *
 180  * Mark the memory stream as secure.  At the very least this means the
 181  * data in the buffer will be cleared when the buffer is finalised.
 182  * This only applies to buffers owned by the stream.
 183  **/
 184 void
 185 camel_stream_mem_set_secure(CamelStreamMem *mem)
 186 {
 187         mem->secure = 1;
 188         /* setup a mem-locked buffer etc?  blah blah, well not yet anyway */
 189 }
 190
 191
 192 /* note: with these functions the caller is the 'owner' of the buffer */
 193
 194 /**
 195  * camel_stream_mem_set_byte_array:
 196  * @mem: a #CamelStreamMem object
 197  * @buffer: a #GByteArray
 198  *
 199  * Set @buffer to be the backing data to the existing #CamelStreamMem, @mem.
 200  *
 201  * Note: @mem will not take ownership of @buffer and so will need to
 202  * be freed separately from @mem.
 203  **/
 204 void
 205 camel_stream_mem_set_byte_array (CamelStreamMem *mem, GByteArray *buffer)
 206 {
 207         if (mem->buffer && mem->owner) {
 208                 if (mem->secure && mem->buffer->len)
 209                         clear_mem (mem->buffer->data, mem->buffer->len);
 210                 g_byte_array_free (mem->buffer, TRUE);
 211         }
 212         mem->owner = FALSE;
 213         mem->buffer = buffer;
 214 }
 215
 216
 217 /**
 218  * camel_stream_mem_set_buffer:
 219  * @mem: a #CamelStreamMem object
 220  * @buffer: a memory buffer
 221  * @len: length of @buffer
 222  *
 223  * Set @buffer to be the backing data to the existing #CamelStreamMem, @mem.
 224  *
 225  * Note: @buffer will be copied into an internal #GByteArray structure
 226  * and so may have resource implications to consider.
 227  **/
 228 void
 229 camel_stream_mem_set_buffer (CamelStreamMem *mem, const char *buffer, size_t len)
 230 {
 231         GByteArray *ba;
 232
 233         ba = g_byte_array_new ();
 234         g_byte_array_append(ba, (const guint8 *)buffer, len);
 235         camel_stream_mem_set_byte_array(mem, ba);
 236         mem->owner = TRUE;
 237 }
 238
 239
 240 static void
 241 camel_stream_mem_finalize (CamelObject *object)
 242 {
 243         CamelStreamMem *s = CAMEL_STREAM_MEM (object);
 244
 245         if (s->buffer && s->owner) {
 246                 /* TODO: we need our own bytearray type since we don't know
 247                    the real size of the underlying buffer :-/ */
 248                 if (s->secure && s->buffer->len)
 249                         clear_mem(s->buffer->data, s->buffer->len);
 250                 g_byte_array_free(s->buffer, TRUE);
 251         }
 252 }
 253
 254 static ssize_t
 255 stream_read (CamelStream *stream, char *buffer, size_t n)
 256 {
 257         CamelStreamMem *camel_stream_mem = CAMEL_STREAM_MEM (stream);
 258         CamelSeekableStream *seekable = CAMEL_SEEKABLE_STREAM (stream);
 259         ssize_t nread;
 260
 261         if (seekable->bound_end != CAMEL_STREAM_UNBOUND)
 262                 n = MIN(seekable->bound_end - seekable->position, n);
 263
 264         nread = MIN (n, camel_stream_mem->buffer->len - seekable->position);
 265         if (nread > 0) {
 266                 memcpy (buffer, camel_stream_mem->buffer->data + seekable->position, nread);
 267                 seekable->position += nread;
 268         } else
 269                 nread = 0;
 270
 271         return nread;
 272 }
 273
 274 static ssize_t
 275 stream_write (CamelStream *stream, const char *buffer, size_t n)
 276 {
 277         CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (stream);
 278         CamelSeekableStream *seekable = CAMEL_SEEKABLE_STREAM (stream);
 279         ssize_t nwrite = n;
 280
 281         if (seekable->bound_end != CAMEL_STREAM_UNBOUND)
 282                 nwrite = MIN(seekable->bound_end - seekable->position, n);
 283
 284         /* FIXME: we shouldn't use g_byte_arrays or g_malloc perhaps? */
 285         if (seekable->position == stream_mem->buffer->len) {
 286                 g_byte_array_append(stream_mem->buffer, (const guint8 *)buffer, nwrite);
 287         } else {
 288                 g_byte_array_set_size(stream_mem->buffer, nwrite + stream_mem->buffer->len);
 289                 memcpy(stream_mem->buffer->data + seekable->position, buffer, nwrite);
 290         }
 291         seekable->position += nwrite;
 292
 293         return nwrite;
 294 }
 295
 296 static gboolean
 297 stream_eos (CamelStream *stream)
 298 {
 299         CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (stream);
 300         CamelSeekableStream *seekable_stream = CAMEL_SEEKABLE_STREAM (stream);
 301
 302         return stream_mem->buffer->len <= seekable_stream->position;
 303 }
 304
 305 static off_t
 306 stream_seek (CamelSeekableStream *stream, off_t offset,
 307              CamelStreamSeekPolicy policy)
 308 {
 309         off_t position;
 310         CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (stream);
 311
 312         switch  (policy) {
 313         case CAMEL_STREAM_SET:
 314                 position = offset;
 315                 break;
 316         case CAMEL_STREAM_CUR:
 317                 position = stream->position + offset;
 318                 break;
 319         case CAMEL_STREAM_END:
 320                 position = (stream_mem->buffer)->len + offset;
 321                 break;
 322         default:
 323                 position = offset;
 324                 break;
 325         }
 326
 327         if (stream->bound_end != CAMEL_STREAM_UNBOUND)
 328                 position = MIN (position, stream->bound_end);
 329         if (stream->bound_start != CAMEL_STREAM_UNBOUND)
 330                 position = MAX (position, 0);
 331         else
 332                 position = MAX (position, stream->bound_start);
 333
 334         if (position > stream_mem->buffer->len) {
 335                 int oldlen = stream_mem->buffer->len;
 336                 g_byte_array_set_size (stream_mem->buffer, position);
 337                 memset (stream_mem->buffer->data + oldlen, 0,
 338                         position - oldlen);
 339         }
 340
 341         stream->position = position;
 342
 343         return position;
 344 }