1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/libfsserver/lib/files/ext2_file_accessor.cc Sat Apr 24 23:15:21 2021 +0200
1.3 @@ -0,0 +1,105 @@
1.4 +/*
1.5 + * A file accessor employing a file provided by an Ext2-compatible filesystem.
1.6 + *
1.7 + * Copyright (C) 2021 Paul Boddie <paul@boddie.org.uk>
1.8 + *
1.9 + * This program is free software; you can redistribute it and/or
1.10 + * modify it under the terms of the GNU General Public License as
1.11 + * published by the Free Software Foundation; either version 2 of
1.12 + * the License, or (at your option) any later version.
1.13 + *
1.14 + * This program is distributed in the hope that it will be useful,
1.15 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
1.16 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.17 + * GNU General Public License for more details.
1.18 + *
1.19 + * You should have received a copy of the GNU General Public License
1.20 + * along with this program; if not, write to the Free Software
1.21 + * Foundation, Inc., 51 Franklin Street, Fifth Floor,
1.22 + * Boston, MA 02110-1301, USA
1.23 + */
1.24 +
1.25 +#include <stdio.h>
1.26 +#include <string.h>
1.27 +#include <sys/stat.h>
1.28 +#include <sys/types.h>
1.29 +
1.30 +#include <algorithm>
1.31 +
1.32 +#include <systypes/fcntl.h>
1.33 +
1.34 +#include "ext2_file_accessor.h"
1.35 +
1.36 +
1.37 +
1.38 +Ext2FileAccessor::Ext2FileAccessor(ext2_file_t file, fileid_t fileid)
1.39 +: Accessor(fileid), _file(file)
1.40 +{
1.41 +}
1.42 +
1.43 +/* Return the size of the file. */
1.44 +
1.45 +offset_t Ext2FileAccessor::get_size()
1.46 +{
1.47 + return ext2fs_file_get_size(_file);
1.48 +}
1.49 +
1.50 +/* Update the size of the file. */
1.51 +
1.52 +void Ext2FileAccessor::set_size(offset_t size)
1.53 +{
1.54 + ext2fs_file_set_size(_file, size);
1.55 +}
1.56 +
1.57 +/* Perform any closing operation on the file. */
1.58 +
1.59 +void Ext2FileAccessor::close()
1.60 +{
1.61 + ext2fs_file_flush(_file);
1.62 + ext2fs_file_close(_file);
1.63 +}
1.64 +
1.65 +/* Data transfer helper methods. */
1.66 +
1.67 +/* Fill the populated portion of a flexpage. */
1.68 +
1.69 +void Ext2FileAccessor::fill_populated(Flexpage *flexpage)
1.70 +{
1.71 + offset_t filepos = flexpage->base_offset;
1.72 + offset_t addr = flexpage->base_addr;
1.73 +
1.74 + /* Tag the region with file state. */
1.75 +
1.76 + flexpage->region->fill(fileid, filepos);
1.77 +
1.78 + /* Fill the region with file content. */
1.79 +
1.80 + ext2fs_file_llseek(_file, filepos, SEEK_SET, NULL);
1.81 +
1.82 + unsigned int nread;
1.83 + ext2fs_file_read(_file, (void *) addr, flexpage->size, &nread);
1.84 +
1.85 + /* Pad the flexpage with zero. */
1.86 +
1.87 + memset((void *) (addr + nread), 0, flexpage->size - nread);
1.88 +}
1.89 +
1.90 +/* Flush the populated portion of a flexpage. */
1.91 +
1.92 +void Ext2FileAccessor::flush_populated(Flexpage *flexpage)
1.93 +{
1.94 + offset_t filepos = flexpage->base_offset;
1.95 + offset_t addr = flexpage->base_addr;
1.96 + offset_t populated_size = std::min(flexpage->size, get_size() - filepos);
1.97 +
1.98 + /* Remove the file state tag from the region. */
1.99 +
1.100 + flexpage->region->flush();
1.101 +
1.102 + /* Copy the populated region to the file. */
1.103 +
1.104 + ext2fs_file_llseek(_file, filepos, SEEK_SET, NULL);
1.105 + ext2fs_file_write(_file, (const void *) addr, populated_size, NULL);
1.106 +}
1.107 +
1.108 +// vim: tabstop=4 expandtab shiftwidth=4