kea/src/lib/datasrc/zone_table_config.h

// Copyright (C) 2013  Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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// PERFORMANCE OF THIS SOFTWARE.

#ifndef DATASRC_ZONE_TABLE_CONFIG_H
#define DATASRC_ZONE_TABLE_CONFIG_H

#include <dns/name.h>
#include <cc/data.h>
#include <datasrc/memory/load_action.h>

#include <map>
#include <string>

namespace isc {
namespace datasrc {
class DataSourceClient;

namespace internal {

/// This class is intended to be an interface between DataSourceClient and
/// memory ZoneTableSegment implementations.  This class understands the
/// configuration parameters for DataSourceClient related to in-memory cache,
/// and convert it to native, type-safe objects so that it can be used by
/// ZoneTableSegment implementations.  It also provides unified interface
/// for getting a list of zones to be loaded in to memory and
/// and memory::LoadAction object that can be used for the load, regardless
/// of the underlying data source properties, i.e., whether it's special
/// "MasterFiles" type or other generic data sources.
///
/// This class is publicly defined because it has to be referenced by both
/// DataSourceClient and ZoneTableSegment (other than for testing purposes),
/// but it's essentially private to these two classes.  It's therefore
/// defined in an "internal" namespace, and isn't expected to be used by
/// other classes or user applications.  Likewise, this file is not expected
/// to be installed with other publicly usable header files.
class ZoneTableConfig {
public:
    ZoneTableConfig(const std::string& datasrc_type,
                    const DataSourceClient* datasrc_client,
                    const data::Element& datasrc_conf);

    /// Return corresponding \c LoadAction for the given name of zone.
    /// It would return a different functor depending on the details of the
    /// underlying data source.
    memory::LoadAction getLoadAction(const dns::Name& zone_name) const;

    /// This allows ZoneTableSegment to iterate over all zones to be loaded
    /// in to memory.  In this initial implementation we directly give
    /// read-only access to the underlying map to minimize the diff, but
    /// it's not clean in terms of encapsulation and performance (eventually
    /// we may have to look up in the underlying data source to get the list
    /// of zones, in which case constructing a map can be very expensive).
    typedef std::map<dns::Name, std::string> Zones;
    const Zones& getZoneConfig() const { return (zone_config_); }

private:
    // client of underlying data source, will be NULL for MasterFile datasrc
    const DataSourceClient* datasrc_client_;
    Zones zone_config_;
};
}
}
}

#endif  // DATASRC_ZONE_TABLE_CONFIG_H

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