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// Copyright (C) 2013-2015,2017 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef DHCP_CONFIG_PARSER_H
#define DHCP_CONFIG_PARSER_H
#include <exceptions/exceptions.h>
#include <cc/data.h>
#include <cc/dhcp_config_error.h>
#include <stdint.h>
#include <string>
#include <map>
namespace isc {
namespace dhcp {
/// @brief Forward declaration to DhcpConfigParser class.
///
/// It is only needed here to define types that are
/// based on this class before the class definition.
class DhcpConfigParser;
/// @brief a pointer to configuration parser
typedef boost::shared_ptr<DhcpConfigParser> ParserPtr;
/// @brief Collection of parsers.
///
/// This container is used to store pointer to parsers for a given scope.
typedef std::vector<ParserPtr> ParserCollection;
/// @brief Combination of parameter name and configuration contents
typedef std::pair<std::string, isc::data::ConstElementPtr> ConfigPair;
/// @brief Base abstract class for all DHCP parsers
///
/// Each instance of a class derived from this class parses one specific config
/// element. Sometimes elements are simple (e.g. a string) and sometimes quite
/// complex (e.g. a subnet). In such case, it is likely that a parser will
/// spawn child parsers to parse child elements in the configuration.
class DhcpConfigParser {
///
/// @name Constructors and Destructor
///
/// Note: The copy constructor and the assignment operator are
/// intentionally defined as private to make it explicit that this is a
/// pure base class.
//@{
private:
// Private constructor and assignment operator assures that nobody
// will be able to copy or assign a parser. There are no defined
// bodies for them.
DhcpConfigParser(const DhcpConfigParser& source);
DhcpConfigParser& operator=(const DhcpConfigParser& source);
protected:
/// @brief The default constructor.
///
/// This is intentionally defined as @c protected as this base class should
/// never be instantiated (except as part of a derived class).
DhcpConfigParser() {}
public:
/// The destructor.
virtual ~DhcpConfigParser() {}
//@}
/// @brief Prepare configuration value.
///
/// This method parses the "value part" of the configuration identifier
/// that corresponds to this derived class and prepares a new value to
/// apply to the server.
///
/// This method must validate the given value both in terms of syntax
/// and semantics of the configuration, so that the server will be
/// validly configured at the time of @c commit(). Note: the given
/// configuration value is normally syntactically validated, but the
/// @c build() implementation must also expect invalid input. If it
/// detects an error it may throw an exception of a derived class
/// of @c isc::Exception.
///
/// Preparing a configuration value will often require resource
/// allocation. If it fails, it may throw a corresponding standard
/// exception.
///
/// This method is not expected to be called more than once in the
/// life of the object. Although multiple calls are not prohibited
/// by the interface, the behavior is undefined.
///
/// @param config_value The configuration value for the identifier
/// corresponding to the derived class.
virtual void build(isc::data::ConstElementPtr config_value) = 0;
/// @brief Apply the prepared configuration value to the server.
///
/// This method is expected to be exception free, and, as a consequence,
/// it should normally not involve resource allocation.
/// Typically it would simply perform exception free assignment or swap
/// operation on the value prepared in @c build().
/// In some cases, however, it may be very difficult to meet this
/// condition in a realistic way, while the failure case should really
/// be very rare. In such a case it may throw, and, if the parser is
/// called via @c configureDhcp4Server(), the caller will convert the
/// exception as a fatal error.
///
/// This method is expected to be called after @c build(), and only once.
/// The result is undefined otherwise.
virtual void commit() = 0;
};
}; // end of isc::dhcp namespace
}; // end of isc namespace
#endif // DHCP_CONFIG_PARSER_H
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