Exheredludis/paludis/util/realpath.cc
Ciaran McCreesh 49750cc619 FSEntry -> FSPath, FSStat
Fixes: ticket:967
2010-08-24 15:47:41 +01:00

99 lines
3.1 KiB
C++

/* vim: set sw=4 sts=4 et foldmethod=syntax : */
/*
* Copyright (c) 2007 David Leverton
*
* This file is part of the Paludis package manager. Paludis is free software;
* you can redistribute it and/or modify it under the terms of the GNU General
* Public License version 2, as published by the Free Software Foundation.
*
* Paludis is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <paludis/util/realpath.hh>
#include <paludis/util/fs_path.hh>
#include <paludis/util/fs_stat.hh>
#include <paludis/util/fs_error.hh>
#include <paludis/util/stringify.hh>
using namespace paludis;
namespace
{
FSPath
do_realpath_with_current_and_root(
const FSPath & file, const FSPath & current, const FSPath & root,
const FSPath & orig_file, const FSPath & orig_current, unsigned & symlinks)
{
if (symlinks >= 40)
throw FSError("Too many symlinks encountered while canonicalising '" + stringify(orig_file) +
"' relative to '" + stringify(orig_current) + "' with root '" + stringify(root) + "'");
FSPath cur(current);
std::string file_str(stringify(file));
if ('/' == file_str[0])
{
file_str.erase(0, 1);
cur = FSPath("/");
}
while (! file_str.empty())
{
std::string::size_type slash(file_str.find('/'));
if (0 == slash)
{
file_str.erase(0, 1);
continue;
}
std::string component(std::string::npos == slash
? file_str : file_str.substr(0, slash));
if (std::string::npos == slash)
file_str.erase();
else
file_str.erase(0, slash + 1);
if ("." == component)
continue;
if (".." == component)
{
cur = cur.dirname();
continue;
}
FSPath full(root / cur / component);
if (full.stat().is_symlink())
cur = do_realpath_with_current_and_root(FSPath(full.readlink()), cur, root, orig_file, orig_current, ++symlinks);
else
cur = cur / component;
}
return cur;
}
}
FSPath
paludis::realpath_with_current_and_root(const FSPath & file, const FSPath & current, const FSPath & root)
{
unsigned symlinks(0);
return do_realpath_with_current_and_root(file, current, root, file, current, symlinks);
}
FSPath
paludis::dereference_with_root(const FSPath & file, const FSPath & root)
{
if (file.stat().is_symlink())
return root / realpath_with_current_and_root(FSPath(file.readlink()), file.dirname().strip_leading(root), root);
else
return file;
}