xahaud/modules/ripple_data/protocol/ripple_KnownFormats.h

//------------------------------------------------------------------------------
/*
    Copyright (c) 2011-2013, OpenCoin, Inc.
*/
//==============================================================================

#ifndef RIPPLE_KNOWNFORMATS_H_INCLUDED
#define RIPPLE_KNOWNFORMATS_H_INCLUDED

/** Manages a list of known formats.

    Each format has a name, an associated KeyType (typically an enumeration),
    and a predefined @ref SOElement.

    @tparam KeyType The type of key identifying the format.
*/
template <class KeyType>
class KnownFormats
{
public:
    /** A known format.
    */
    class Item
    {
    public:
        Item (char const* name, KeyType type)
            : m_name (name)
            , m_type (type)
        {
        }

        Item& operator<< (SOElement const& el)
        {
            elements.push_back (el);

            return *this;
        }

        /** Retrieve the name of the format.
        */
        std::string const& getName () const noexcept
        {
            return m_name;
        }

        /** Retrieve the transaction type this format represents.
        */
        KeyType getType () const noexcept
        {
            return m_type;
        }

    public:
        // VFALCO TODO make an accessor for this
        SOTemplate elements;

    private:
        std::string const m_name;
        KeyType const m_type;
    };

private:
    // VFALCO TODO use String instead of std::string
    typedef std::map <std::string, Item*> NameMap;
    typedef std::map <KeyType, Item*> TypeMap;

public:
    /** Create the known formats object.

        Derived classes will load the object will all the known formats.
    */
    KnownFormats ()
    {
    }

    /** Destroy the known formats object.

        The defined formats are deleted.
    */
    ~KnownFormats ()
    {
    }

    /** Retrieve the type for a format specified by name.

        If the format name is unknown, an exception is thrown.

        @param  name The name of the type.
        @return      The type.
    */
    KeyType findTypeByName (std::string const name) const
    {
        Item const* const result = findByName (name);

        if (result != nullptr)
        {
            return result->getType ();
        }
        else
        {
            throw std::runtime_error ("Unknown format name");
        }
    }

    /** Retrieve a format based on its type.
    */
    // VFALCO TODO Can we just return the SOElement& ?
    Item const* findByType (KeyType type) const noexcept
    {
        Item* result = nullptr;

        typename TypeMap::const_iterator const iter = m_types.find (type);

        if (iter != m_types.end ())
        {
            result = iter->second;
        }

        return result;
    }

protected:
    /** Retrieve a format based on its name.
    */
    Item const* findByName (std::string const& name) const noexcept
    {
        Item* result = nullptr;

        typename NameMap::const_iterator const iter = m_names.find (name);

        if (iter != m_names.end ())
        {
            result = iter->second;
        }

        return result;
    }

    /** Add a new format.

        The new format has the set of common fields already added.

        @param name The name of this format.
        @param type The type of this format.

        @return The created format.
    */
    Item& add (char const* name, KeyType type)
    {
        Item& item = *m_formats.add (new Item (name, type));

        addCommonFields (item);

        m_types [item.getType ()] = &item;
        m_names [item.getName ()] = &item;

        return item;
    }

    /** Adds common fields.

        This is called for every new item.
    */
    virtual void addCommonFields (Item& item) = 0;

private:
    OwnedArray <Item> m_formats;
    NameMap m_names;
    TypeMap m_types;
};

#endif