/* -*-mode:c++; c-file-style: "gnu";-*- */
/*
 *  $Id: CgiInput.h,v 1.7 2007/07/02 18:48:17 sebdiaz Exp $
 *
 *  Copyright (C) 1996 - 2004 Stephen F. Booth <sbooth@gnu.org>
 *                       2007 Sebastien DIAZ <sebastien.diaz@gmail.com>
 *  Part of the GNU cgicc library, http://www.gnu.org/software/cgicc
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 3 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA 
 */

#ifndef _CGIINPUT_H_
#define _CGIINPUT_H_ 1

#ifdef __GNUG__
#  pragma interface
#endif

/*! \file CgiInput.h
 * \brief Class that abstracts a data source
 *
 * This class allows the data source for the CGI application to be
 * something other than standard input.
 */

#include <string>

#include "cgicc/CgiDefs.h"

namespace cgicc {

  // ============================================================
  // Class CgiInput
  // ============================================================
  
  /*! \class CgiInput CgiInput.h cgicc/CgiInput.h 
   * \brief Class that abstracts a data source
   *
   * The \c CgiInput class is an abstraction for all input data to the
   * CGI application. This allows input data to come from something other than 
   * standard input (cin).  This is useful, in fact necessary, when using
   * %cgicc with FastCgi.
   * Library users wishing to exploit this functionality should create a
   * subclass and override the \c read and \c getenv methods.
   */
  class CGICC_API CgiInput
  {
  public:
    
    // ============================================================
    
    /*! \name Constructor and Destructor */
    //@{
    
    /*! 
     * \brief Constructor
     *
     * Create a new CgiInput object
     */
    inline
    CgiInput()
    {}
    
    /*! 
     * \brief Copy constructor
     *
     * If you subclass CgiInput, you <strong>must</strong> overload
     * operator=
     * \param input The CgiInput object to copy
     */
    inline
    CgiInput(const CgiInput& input)
    { operator=(input); }
    
    /*!
     * \brief Destructor 
     *
     * Delete this CgiInput object
     */
    virtual ~CgiInput();
    //@}
    
    
    // ============================================================
    
    /*! \name Overloaded Operators */
    //@{
    
    /*!
     * \brief Compare two CgiInput objects for equality
     *
     * In the default implementation all CgiInput objects are equal
     * \param input The CgiInput object to compare to this one
     * \return \c true
     */
    inline bool 
    operator== (const CgiInput& /*input*/) 		const
    { return true; }
    
    /*!
     * \brief Compare two CgiInput objects for inequality
     *
     * In the default implementation all CgiInput objects are equal
     * \param input The CgiInput object to compare to this one
     * \return \c false
     */
    inline bool
    operator!= (const CgiInput& input) 			const
    { return ! operator==(input); }
    
    /*!
     * \brief Assign one CgiInput to another
     *
     * Does nothing in the default implementation
     * \param input The CgiInput object to copy
     * \return A reference to this.
     */
    inline CgiInput& 
    operator= (const CgiInput& /*input*/)
    { return *this; }
    //@}
    
    // ============================================================
    
    /*! \name Data Sources */
    //@{
    
    /*!
     * \brief Read data from a data source
     *
     * In the default implementation, this is a wrapper for \c cin.read()
     * \param data The target buffer
     * \param length The number of characters to read
     * \return The number of characters read
     */
    virtual size_t read(char *data, size_t length);
    
    /*!
     * \brief Query the value of an environment variable
     *
     * In the default implementation, this is a wrapper for std::getenv()
     * \param varName The name of an environment variable
     * \return The value of the requested environment variable, or an empty
     * string if not found.
     */
    virtual std::string getenv(const char *varName);
    //@}
  };
  
} // namespace cgicc

#endif /* ! _CGIINPUT_H_ */
