append_filename_arg.h

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/* Copyright (C) 2003,2004,2007,2012,2019 Olly Betts
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#ifndef XAPIAN_INCLUDED_APPEND_FILENAME_ARG_H
#define XAPIAN_INCLUDED_APPEND_FILENAME_ARG_H

#include <cstring>
#include <string>

static bool
append_filename_argument(std::string& cmd,
                         const std::string& arg,
                         bool leading_space = true) {
#ifdef __WIN32__
    cmd.reserve(cmd.size() + arg.size() + 5);
    // Prevent a leading "-" on the filename being interpreted as a command
    // line option.
    const char* prefix = (arg[0] == '-') ? " \".\\" : " \"";
    if (!leading_space)
        ++prefix;
    cmd += prefix;

    for (std::string::const_iterator i = arg.begin(); i != arg.end(); ++i) {
        if (*i == '/') {
            // Convert Unix path separators to backslashes.  C library
            // functions understand "/" in paths, but we are going to
            // call commands like "xcopy" or "rd" which don't.
            cmd += '\\';
        } else if (*i < 32 || std::strchr("<>\"|*?", *i)) {
            // Check for illegal characters in filename.
            return false;
        } else {
            cmd += *i;
        }
    }
    cmd += '"';
#else
    // Allow for the typical case of a filename without single quote characters
    // in - this reserving is just an optimisation, and the string will grow
    // larger if necessary.
    cmd.reserve(cmd.size() + arg.size() + 5);

    // Prevent a leading "-" on the filename being interpreted as a command
    // line option.
    const char* prefix = (arg[0] == '-') ? " './" : " '";
    if (!leading_space)
        ++prefix;
    cmd += prefix;

    for (std::string::const_iterator i = arg.begin(); i != arg.end(); ++i) {
        if (*i == '\'') {
            // Wrapping the whole argument in single quotes works for
            // everything except a single quote - for that we drop out of
            // single quotes, then use a backslash-escaped single quote, then
            // re-enter single quotes.
            cmd += "'\\''";
            continue;
        }
        cmd += *i;
    }
    cmd += '\'';
#endif
    return true;
}

#endif // XAPIAN_INCLUDED_APPEND_FILENAME_ARG_H