/*
**      SWISH++
**      filter.h
**
**      Copyright (C) 1998  Paul J. Lucas
**
**      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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifndef filter_H
#define filter_H

// standard
#include <string>
#include <unistd.h>                     /* for unlink(2) */

//*****************************************************************************
//
// SYNOPSIS
//
        class filter
//
// DESCRIPTION
//
//      A filter is a light-weight class that contains a Unix command-line and
//      knows how to execute itself on a file to create a filtered file.  The
//      destructor deletes the filtered file.
//
//*****************************************************************************
{
public:
    explicit filter( char const *command ) : command_template_( command ) {}
    ~filter();

    // default copy constructor is fine
    // default assignment operator is fine

    char const* substitute( char const *file_name );
    char const* substitute( std::string const &file_name );
    char const* exec() const;
private:
    char const* command_template_;
    //
    // The above really should be const, but then we'd need to define a
    // non-default operator=().  It's simpler and harmless just to leave the
    // const out.
    //

    std::string command_;
    std::string target_file_name_;
};

////////// Inlines ////////////////////////////////////////////////////////////

inline filter::~filter() {
    if ( !target_file_name_.empty() )
        ::unlink( target_file_name_.c_str() );
}

inline char const* filter::substitute( std::string const &file_name ) {
    return substitute( file_name.c_str() );
}

#endif  /* filter_H */
/* vim:set et sw=4 ts=4: */
