xapian-core/common/append_filename_arg.h

   1 /** @file
   2  *  @brief Append filename argument to a command string with suitable escaping
   3  */
   4 /* Copyright (C) 2003,2004,2007,2012,2019 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of the
   9  * License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #ifndef XAPIAN_INCLUDED_APPEND_FILENAME_ARG_H
  22 #define XAPIAN_INCLUDED_APPEND_FILENAME_ARG_H
  23
  24 #include <cstring>
  25 #include <string>
  26
  27 /// Append filename argument arg to command cmd with suitable escaping.
  28 static bool
  29 append_filename_argument(std::string& cmd,
  30                          const std::string& arg,
  31                          bool leading_space = true) {
  32 #ifdef __WIN32__
  33     cmd.reserve(cmd.size() + arg.size() + 5);
  34     // Prevent a leading "-" on the filename being interpreted as a command
  35     // line option.
  36     const char* prefix = (arg[0] == '-') ? " \".\\" : " \"";
  37     if (!leading_space)
  38         ++prefix;
  39     cmd += prefix;
  40
  41     for (char ch : arg) {
  42         if (ch == '/') {
  43             // Convert Unix path separators to backslashes.  C library
  44             // functions understand "/" in paths, but we are going to
  45             // call commands like "xcopy" or "rd" which don't.
  46             cmd += '\\';
  47         } else if (ch < 32 || std::strchr("<>\"|*?", ch)) {
  48             // Check for illegal characters in filename.
  49             return false;
  50         } else {
  51             cmd += ch;
  52         }
  53     }
  54     cmd += '"';
  55 #else
  56     // Allow for the typical case of a filename without single quote characters
  57     // in - this reserving is just an optimisation, and the string will grow
  58     // larger if necessary.
  59     cmd.reserve(cmd.size() + arg.size() + 5);
  60
  61     // Prevent a leading "-" on the filename being interpreted as a command
  62     // line option.
  63     const char* prefix = (arg[0] == '-') ? " './" : " '";
  64     if (!leading_space)
  65         ++prefix;
  66     cmd += prefix;
  67
  68     for (char ch : arg) {
  69         if (ch == '\'') {
  70             // Wrapping the whole argument in single quotes works for
  71             // everything except a single quote - for that we drop out of
  72             // single quotes, then use a backslash-escaped single quote, then
  73             // re-enter single quotes.
  74             cmd += "'\\''";
  75             continue;
  76         }
  77         cmd += ch;
  78     }
  79     cmd += '\'';
  80 #endif
  81     return true;
  82 }
  83
  84 #endif // XAPIAN_INCLUDED_APPEND_FILENAME_ARG_H