/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "<WebSig>" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 2001, Institute for
 * Data Communications Systems, <http://www.nue.et-inf.uni-siegen.de/>.
 * The development of this software was partly funded by the European 
 * Commission in the <WebSig> project in the ISIS Programme. 
 * For more information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

/*
 * XSEC
 *
 * XSECURIResolver := Virtual Interface class that takes a URI and
 *                    creates a binary input stream from it.
 *
 * Author(s): Berin Lautenbach
 *
 * $ID$
 *
 * $LOG$
 *
 */

#ifndef XSECURIRESOLVER_INCLUDE
#define XSECURIRESOLVER_INCLUDE

#include <xsec/framework/XSECDefs.hpp>

XSEC_DECLARE_XERCES_CLASS(BinInputStream);

/**
 * @ingroup pubsig
 */
/*\@{*/

/**
 * @brief Interface class for resolving URIs.
 *
 * The XML Digital Signature standard makes heavy use of URIs to
 * identify information to be referenced and signed.
 *
 * The library internally handles reference URIs within the
 * document that contains the signature, but uses URIResolver
 * classes to dereference a URI into a byte stream that can
 * then be processed.
 *
 * The interface class allows others to re-implement and install
 * their own resolves according to their needs.  The basic
 * implementations found in the library are just that - very basic.
 * Enough to do the job for interoperability testing, but not
 * enough to provide robustness in a major application.
 *
 */

class DSIG_EXPORT XSECURIResolver {

public:

	/** @name Constructors and Destructors */
	//@{

	XSECURIResolver() {};
	virtual ~XSECURIResolver() {};

	//@}

	/** @name Interface Methods */
	//@{

	/**
	 * \brief Create a BYTE_STREAM from a URI.
	 *
	 * The resolver is required to take the input URI and
	 * dereference it to an actual stream of octets.
	 *
	 * The octets are provided back to the library using
	 * the Xerces BinInputStream class.
	 *
	 * @note The returned stream is "owned" by the caller, which
	 * will delete it when processing is complete.
	 * @param uri The string containing the URI to be de-referenced.  NULL
	 * if this is an anonymous reference.
	 * @returns The octet stream corresponding to the URI.
	 */

	virtual BinInputStream * resolveURI(const XMLCh * uri) = 0;

	/**
	 * \brief Clone the resolver to be installed in a new object.
	 *
	 * When URIResolvers are passed into signatures and other
	 * objects, they are cloned and control of the original object
	 * is left with the caller.
	 *
	 */

	virtual XSECURIResolver * clone(void) = 0;

	//@}

};


#endif /* XSECURIRESOLVER_INCLUDE */