// Copyright (C) 2009-2015 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 CONFIG_DATA_H
#define CONFIG_DATA_H 1

#include <string>
#include <vector>

#include <config/module_spec.h>
#include <exceptions/exceptions.h>

namespace isc {
namespace config {

/// This exception is thrown when the caller is trying to access
/// data that doesn't exist (i.e. with an identifier that does not
/// point to anything defined in the .spec file)
class DataNotFoundError : public isc::Exception {
public:
    DataNotFoundError(const char* file, size_t line, const char* what) :
        isc::Exception(file, line, what) {}
};

class ConfigData {
public:
    /// Constructs a ConfigData option with no specification and an
    /// empty configuration.
    ConfigData() { _config = isc::data::Element::createMap(); };

    /// Constructs a ConfigData option with the given specification
    /// and an empty configuration.
    /// \param module_spec A ModuleSpec for the relevant module
    ConfigData(const ModuleSpec& module_spec) : _module_spec(module_spec) {
        _config = isc::data::Element::createMap();
    }

    virtual ~ConfigData() {};

    /// Returns the value currently set for the given identifier
    /// If no value is set, the default value (as specified by the
    /// .spec file) is returned. If there is no value and no default,
    /// an empty ElementPtr is returned.
    /// Raises a DataNotFoundError if the identifier is bad.
    /// \param identifier The identifier pointing to the configuration
    ///        value that is to be returned
    isc::data::ConstElementPtr getValue(const std::string& identifier) const;

    /// Returns the default value for the given identifier.
    ///
    /// \exception DataNotFoundError if the given identifier does not
    ///            exist, or if the given value has no specified default
    ///
    /// \param identifier The identifier pointing to the configuration
    ///        value for which the default is to be returned
    /// \return ElementPtr containing the default value
    isc::data::ConstElementPtr getDefaultValue(const std::string& identifier) const;

    /// Returns the value currently set for the given identifier
    /// If no value is set, the default value (as specified by the
    /// .spec file) is returned. If there is no value and no default,
    /// an empty ElementPtr is returned.
    /// Raises a DataNotFoundError if the identifier is bad.
    /// \param is_default will be set to true if the value is taken
    ///                   from the specifications item_default setting,
    ///                   false otherwise
    /// \param identifier The identifier pointing to the configuration
    ///        value that is to be returned
    isc::data::ConstElementPtr getValue(bool& is_default,
                                        const std::string& identifier) const;

    /// Returns the ModuleSpec associated with this ConfigData object
    const ModuleSpec& getModuleSpec() const { return (_module_spec); }

    /// Set the ModuleSpec associated with this ConfigData object
    void setModuleSpec(ModuleSpec module_spec) { _module_spec = module_spec; };

    /// Set the local configuration (i.e. all non-default values)
    /// \param config An ElementPtr pointing to a MapElement containing
    ///        *all* non-default configuration values. Existing values
    ///        will be removed.
    void setLocalConfig(isc::data::ElementPtr config) { _config = config; }

    /// Returns the local (i.e. non-default) configuration.
    /// \return An ElementPtr pointing to a MapElement containing all
    ///         non-default configuration options.
    isc::data::ElementPtr getLocalConfig() { return (_config); }

    /// Returns a list of all possible configuration options as specified
    ///         by the ModuleSpec.
    /// \param identifier If given, show the items at the given identifier
    ///                   (iff that is also a MapElement)
    /// \param recurse If true, child MapElements will be traversed to
    ///                add their identifiers to the result list
    /// \return An ElementPtr pointing to a ListElement containing
    ///         StringElements that specify the identifiers at the given
    ///         location (or all possible identifiers if identifier==""
    ///         and recurse==false)
    isc::data::ConstElementPtr getItemList(const std::string& identifier = "",
                                           bool recurse = false) const;

    /// \brief Returns a map of the top-level configuration items, as
    /// currently set or their defaults.
    ///
    /// \return An ElementPtr pointing to a MapElement containing
    ///         the top-level configuration items
    isc::data::ConstElementPtr getFullConfig() const;

private:
    isc::data::ElementPtr _config;
    ModuleSpec _module_spec;
};

}
}
#endif

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