camel/camel-stream-fs.c

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
   2 /* camel-stream-fs.c : file system based stream */
   3
   4 /*
   5  * Authors: Bertrand Guiheneuf <bertrand@helixcode.com>
   6  *          Michael Zucchi <notzed@ximian.com>
   7  *
   8  * Copyright 1999-2003 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 <string.h>
  31 #include <unistd.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34
  35 #include <glib.h>
  36 #include <glib/gstdio.h>
  37
  38 #include "camel-file-utils.h"
  39 #include "camel-operation.h"
  40 #include "camel-private.h"
  41 #include "camel-stream-fs.h"
  42
  43 static CamelSeekableStreamClass *parent_class = NULL;
  44
  45 /* Returns the class for a CamelStreamFS */
  46 #define CSFS_CLASS(so) CAMEL_STREAM_FS_CLASS (CAMEL_OBJECT_GET_CLASS(so))
  47
  48 static ssize_t stream_read   (CamelStream *stream, char *buffer, size_t n);
  49 static ssize_t stream_write  (CamelStream *stream, const char *buffer, size_t n);
  50 static int stream_flush  (CamelStream *stream);
  51 static int stream_close  (CamelStream *stream);
  52 static off_t stream_seek (CamelSeekableStream *stream, off_t offset,
  53                           CamelStreamSeekPolicy policy);
  54
  55 static void
  56 camel_stream_fs_class_init (CamelStreamFsClass *camel_stream_fs_class)
  57 {
  58         CamelSeekableStreamClass *camel_seekable_stream_class =
  59                 CAMEL_SEEKABLE_STREAM_CLASS (camel_stream_fs_class);
  60         CamelStreamClass *camel_stream_class =
  61                 CAMEL_STREAM_CLASS (camel_stream_fs_class);
  62
  63         parent_class = CAMEL_SEEKABLE_STREAM_CLASS (camel_type_get_global_classfuncs (camel_seekable_stream_get_type ()));
  64
  65         /* virtual method overload */
  66         camel_stream_class->read = stream_read;
  67         camel_stream_class->write = stream_write;
  68         camel_stream_class->flush = stream_flush;
  69         camel_stream_class->close = stream_close;
  70
  71         camel_seekable_stream_class->seek = stream_seek;
  72 }
  73
  74 static void
  75 camel_stream_fs_init (gpointer object, gpointer klass)
  76 {
  77         CamelStreamFs *stream = CAMEL_STREAM_FS (object);
  78
  79         stream->fd = -1;
  80         ((CamelSeekableStream *)stream)->bound_end = CAMEL_STREAM_UNBOUND;
  81 }
  82
  83 static void
  84 camel_stream_fs_finalize (CamelObject *object)
  85 {
  86         CamelStreamFs *stream_fs = CAMEL_STREAM_FS (object);
  87
  88         if (stream_fs->fd != -1)
  89                 close (stream_fs->fd);
  90 }
  91
  92
  93 CamelType
  94 camel_stream_fs_get_type (void)
  95 {
  96         static CamelType camel_stream_fs_type = CAMEL_INVALID_TYPE;
  97
  98         if (camel_stream_fs_type == CAMEL_INVALID_TYPE) {
  99                 camel_stream_fs_type = camel_type_register (camel_seekable_stream_get_type (), "CamelStreamFs",
 100                                                             sizeof (CamelStreamFs),
 101                                                             sizeof (CamelStreamFsClass),
 102                                                             (CamelObjectClassInitFunc) camel_stream_fs_class_init,
 103                                                             NULL,
 104                                                             (CamelObjectInitFunc) camel_stream_fs_init,
 105                                                             (CamelObjectFinalizeFunc) camel_stream_fs_finalize);
 106         }
 107
 108         return camel_stream_fs_type;
 109 }
 110
 111 /**
 112  * camel_stream_fs_new_with_fd:
 113  * @fd: a file descriptor
 114  *
 115  * Creates a new fs stream using the given file descriptor @fd as the
 116  * backing store. When the stream is destroyed, the file descriptor
 117  * will be closed.
 118  *
 119  * Returns a new #CamelStreamFs
 120  **/
 121 CamelStream *
 122 camel_stream_fs_new_with_fd (int fd)
 123 {
 124         CamelStreamFs *stream_fs;
 125         off_t offset;
 126
 127         if (fd == -1)
 128                 return NULL;
 129
 130         stream_fs = CAMEL_STREAM_FS (camel_object_new (camel_stream_fs_get_type ()));
 131         stream_fs->fd = fd;
 132         offset = lseek (fd, 0, SEEK_CUR);
 133         if (offset == -1)
 134                 offset = 0;
 135         CAMEL_SEEKABLE_STREAM (stream_fs)->position = offset;
 136
 137         return CAMEL_STREAM (stream_fs);
 138 }
 139
 140 /**
 141  * camel_stream_fs_new_with_fd_and_bounds:
 142  * @fd: a file descriptor
 143  * @start: the first valid position in the file
 144  * @end: the first invalid position in the file, or #CAMEL_STREAM_UNBOUND
 145  *
 146  * Gets a stream associated with the given file descriptor and bounds.
 147  * When the stream is destroyed, the file descriptor will be closed.
 148  *
 149  * Returns the bound stream
 150  **/
 151 CamelStream *
 152 camel_stream_fs_new_with_fd_and_bounds (int fd, off_t start, off_t end)
 153 {
 154         CamelStream *stream;
 155
 156         stream = camel_stream_fs_new_with_fd (fd);
 157         camel_seekable_stream_set_bounds (CAMEL_SEEKABLE_STREAM (stream), start, end);
 158
 159         return stream;
 160 }
 161
 162 /**
 163  * camel_stream_fs_new_with_name:
 164  * @name: a local filename
 165  * @flags: flags as in open(2)
 166  * @mode: a file mode
 167  *
 168  * Creates a new #CamelStreamFs corresponding to the named file, flags,
 169  * and mode.
 170  *
 171  * Returns the new stream, or %NULL on error.
 172  **/
 173 CamelStream *
 174 camel_stream_fs_new_with_name (const char *name, int flags, mode_t mode)
 175 {
 176         int fd;
 177
 178         fd = g_open (name, flags|O_BINARY, mode);
 179         if (fd == -1) {
 180                 return NULL;
 181         }
 182
 183         return camel_stream_fs_new_with_fd (fd);
 184 }
 185
 186 /**
 187  * camel_stream_fs_new_with_name_and_bounds:
 188  * @name: a local filename
 189  * @flags: flags as in open(2)
 190  * @mode: a file mode
 191  * @start: the first valid position in the file
 192  * @end: the first invalid position in the file, or #CAMEL_STREAM_UNBOUND
 193  *
 194  * Creates a new CamelStream corresponding to the given arguments.
 195  *
 196  * Returns the stream, or %NULL on error.
 197  **/
 198 CamelStream *
 199 camel_stream_fs_new_with_name_and_bounds (const char *name, int flags,
 200                                           mode_t mode, off_t start, off_t end)
 201 {
 202         CamelStream *stream;
 203
 204         stream = camel_stream_fs_new_with_name (name, flags, mode);
 205         if (stream == NULL)
 206                 return NULL;
 207
 208         camel_seekable_stream_set_bounds (CAMEL_SEEKABLE_STREAM (stream),
 209                                           start, end);
 210
 211         return stream;
 212 }
 213
 214
 215 static ssize_t
 216 stream_read (CamelStream *stream, char *buffer, size_t n)
 217 {
 218         CamelStreamFs *stream_fs = CAMEL_STREAM_FS (stream);
 219         CamelSeekableStream *seekable = CAMEL_SEEKABLE_STREAM (stream);
 220         ssize_t nread;
 221
 222         if (seekable->bound_end != CAMEL_STREAM_UNBOUND)
 223                 n = MIN (seekable->bound_end - seekable->position, n);
 224
 225         if ((nread = camel_read (stream_fs->fd, buffer, n)) > 0)
 226                 seekable->position += nread;
 227         else if (nread == 0)
 228                 stream->eos = TRUE;
 229
 230         return nread;
 231 }
 232
 233 static ssize_t
 234 stream_write (CamelStream *stream, const char *buffer, size_t n)
 235 {
 236         CamelStreamFs *stream_fs = CAMEL_STREAM_FS (stream);
 237         CamelSeekableStream *seekable = CAMEL_SEEKABLE_STREAM (stream);
 238         ssize_t nwritten;
 239
 240         if (seekable->bound_end != CAMEL_STREAM_UNBOUND)
 241                 n = MIN (seekable->bound_end - seekable->position, n);
 242
 243         if ((nwritten = camel_write (stream_fs->fd, buffer, n)) > 0)
 244                 seekable->position += nwritten;
 245
 246         return nwritten;
 247 }
 248
 249 static int
 250 stream_flush (CamelStream *stream)
 251 {
 252         return fsync(((CamelStreamFs *)stream)->fd);
 253 }
 254
 255 static int
 256 stream_close (CamelStream *stream)
 257 {
 258         if (close (((CamelStreamFs *)stream)->fd) == -1)
 259                 return -1;
 260
 261         ((CamelStreamFs *)stream)->fd = -1;
 262         return 0;
 263 }
 264
 265 static off_t
 266 stream_seek (CamelSeekableStream *stream, off_t offset, CamelStreamSeekPolicy policy)
 267 {
 268         CamelStreamFs *stream_fs = CAMEL_STREAM_FS (stream);
 269         off_t real = 0;
 270
 271         switch (policy) {
 272         case CAMEL_STREAM_SET:
 273                 real = offset;
 274                 break;
 275         case CAMEL_STREAM_CUR:
 276                 real = stream->position + offset;
 277                 break;
 278         case CAMEL_STREAM_END:
 279                 if (stream->bound_end == CAMEL_STREAM_UNBOUND) {
 280                         real = lseek(stream_fs->fd, offset, SEEK_END);
 281                         if (real != -1) {
 282                                 if (real<stream->bound_start)
 283                                         real = stream->bound_start;
 284                                 stream->position = real;
 285                         }
 286                         return real;
 287                 }
 288                 real = stream->bound_end + offset;
 289                 break;
 290         }
 291
 292         if (stream->bound_end != CAMEL_STREAM_UNBOUND)
 293                 real = MIN (real, stream->bound_end);
 294         real = MAX (real, stream->bound_start);
 295
 296         real = lseek(stream_fs->fd, real, SEEK_SET);
 297         if (real == -1)
 298                 return -1;
 299
 300         if (real != stream->position && ((CamelStream *)stream)->eos)
 301                 ((CamelStream *)stream)->eos = FALSE;
 302
 303         stream->position = real;
 304
 305         return real;
 306 }