xapian-applications/omega/runfilter.h

   1 /* runfilter.h: run an external filter and capture its output in a std::string.
   2  *
   3  * Copyright (C) 2007,2013,2015 Olly Betts
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  18  */
  19
  20 #ifndef OMEGA_INCLUDED_RUNFILTER_H
  21 #define OMEGA_INCLUDED_RUNFILTER_H
  22
  23 #include <string>
  24 #include <cstdio>
  25
  26 /// Exception thrown if we encounter a read error.
  27 struct ReadError {
  28     const char * msg;
  29     int status;
  30     explicit ReadError(const char * m) : msg(m) { }
  31     explicit ReadError(int s) : msg(NULL), status(s) { }
  32     std::string str() const { if (msg) return msg; char buf[32]; std::sprintf(buf, "0x%08x", status); return buf; }
  33 };
  34
  35 /// Exception thrown if the filter program isn't found.
  36 struct NoSuchFilter { };
  37
  38 /// Initialise the runfilter module.
  39 void runfilter_init();
  40
  41 /** Run command @a cmd, capture its stdout, and return it as a std::string.
  42  *
  43  *  @param use_shell  If false, try to avoid using a shell to run the command.
  44  *
  45  *  Note: use_shell=false mode assumes only single quotes are used (double
  46  *  quotes and backslash quoting (aside from in the four character sequence
  47  *  '\'' within single quotes) aren't currently handled).  This is only
  48  *  currently supported on Unix-like systems - other systems will ignore
  49  *  use_shell and always use the same code path (which may or may not involve
  50  *  some analog of the Unix shell).
  51  */
  52 std::string stdout_to_string(const std::string &cmd, bool use_shell);
  53
  54 #endif // OMEGA_INCLUDED_RUNFILTER_H