chilon Code

#ifndef CHILON_FILESYSTEM_REALPATH_HPP
#define CHILON_FILESYSTEM_REALPATH_HPP

#include <chilon/iterator_range.hpp>

#include <algorithm>

#include <fcntl.h>
#include <limits.h>

namespace chilon { namespace filesystem {

typedef char realpath_type[PATH_MAX];

/// Like libc's realpath but ignore the last path component and
/// append it to the result.
static char *realpath_new(char const *path, realpath_type& can_path) {
    auto path_end = chilon::end(path);
    char *realpath_end;

    realpath_type realpath_parent;

    for (;;--path_end) {
        if (path_end == path) {
            realpath_parent[0] = '.';
            realpath_end = realpath_parent + 1;
            break;
        }
        else if (*path_end == '/') {
            std::copy(path, path_end, realpath_parent);
            realpath_end = realpath_parent + (path_end - path);
            ++path_end;
            break;
        }
    }

    *realpath_end = '\0';

    if (! ::realpath(realpath_parent, can_path))
        return 0;

    realpath_end = chilon::end(can_path);
    *realpath_end = '/';
    for (++realpath_end; *path_end != '\0'; ++path_end) {
        // TODO: check haven't overflown PATH_MAX
        *realpath_end = *path_end;
        ++realpath_end;
    }
    *realpath_end = '\0';

    return can_path;
}

/// Like libc's realpath but doesn't assume the last path component exists
static inline char *realpath(char const *path, realpath_type& can_path) {
    return access(path, F_OK) ?
        realpath_new(path, can_path) :
        ::realpath(path, can_path);
}

} }
#endif