fairport/ndb/page.h

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#ifndef FAIRPORT_NDB_PAGE_H
#define FAIRPORT_NDB_PAGE_H

#include <vector>

#include "fairport/util/btree.h"
#include "fairport/util/util.h"

#include "fairport/ndb/database_iface.h"

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable:4250)
#endif

namespace fairport
{


class page
{
public:
    page(const shared_db_ptr& db, const page_info& pi)
        : m_db(db), m_pid(pi.id), m_address(pi.address) { }

    page_id get_page_id() const { return m_pid; }

    ulonglong get_address() const { return m_address; }

protected:
    shared_db_ptr get_db_ptr() const { return shared_db_ptr(m_db); }
    weak_db_ptr m_db;       
    page_id m_pid;          
    ulonglong m_address;    
};

template<typename K, typename V>
class bt_page : 
    public page, 
    public virtual btree_node<K,V>
{
public:
    bt_page(const shared_db_ptr& db, const page_info& pi, ushort level)
        : page(db, pi), m_level(level) { }

    ushort get_level() const { return m_level; }

private:
    ushort m_level; 
};

template<typename K, typename V>
class bt_nonleaf_page : 
    public bt_page<K,V>, 
    public btree_node_nonleaf<K,V>, 
    public std::tr1::enable_shared_from_this<bt_nonleaf_page<K,V> >
{
public:
#ifndef BOOST_NO_RVALUE_REFERENCES
    bt_nonleaf_page(const shared_db_ptr& db, const page_info& pi, ushort level, std::vector<std::pair<K, page_info> > subpi)
        : bt_page<K,V>(db, pi, level), m_page_info(std::move(subpi)), m_child_pages(m_page_info.size()) { }
#else
    bt_nonleaf_page(const shared_db_ptr& db, const page_info& pi, ushort level, const std::vector<std::pair<K, page_info> >& subpi)
        : bt_page<K,V>(db, pi, level), m_page_info(subpi), m_child_pages(m_page_info.size()) { }
#endif

    // btree_node_nonleaf implementation
    const K& get_key(uint pos) const { return m_page_info[pos].first; }
    bt_page<K,V>* get_child(uint pos);
    const bt_page<K,V>* get_child(uint pos) const;
    uint num_values() const { return m_child_pages.size(); }

private:
    std::vector<std::pair<K, page_info> > m_page_info;   
    mutable std::vector<std::tr1::shared_ptr<bt_page<K,V> > > m_child_pages; 
};

template<typename K, typename V>
class bt_leaf_page : 
    public bt_page<K,V>, 
    public btree_node_leaf<K,V>, 
    public std::tr1::enable_shared_from_this<bt_leaf_page<K,V> >
{
public:
#ifndef BOOST_NO_RVALUE_REFERENCES
    bt_leaf_page(const shared_db_ptr& db, const page_info& pi, std::vector<std::pair<K,V> > data)
        : bt_page<K,V>(db, pi, 0), m_page_data(std::move(data)) { }
#else
    bt_leaf_page(const shared_db_ptr& db, const page_info& pi, const std::vector<std::pair<K,V> >& data)
        : bt_page<K,V>(db, pi, 0), m_page_data(data) { }
#endif

    // btree_node_leaf implementation
    const V& get_value(uint pos) const
        { return m_page_data[pos].second; }
    const K& get_key(uint pos) const
        { return m_page_data[pos].first; }
    uint num_values() const
        { return m_page_data.size(); }

private:
    std::vector<std::pair<K,V> > m_page_data; 
};
template<>
inline bt_page<block_id, block_info>* bt_nonleaf_page<block_id, block_info>::get_child(uint pos)
{
    if(m_child_pages[pos] == NULL)
    {
        m_child_pages[pos] = this->get_db_ptr()->read_bbt_page(m_page_info[pos].second);
    }

    return m_child_pages[pos].get();
}

template<>
inline const bt_page<block_id, block_info>* bt_nonleaf_page<block_id, block_info>::get_child(uint pos) const
{
    if(m_child_pages[pos] == NULL)
    {
        m_child_pages[pos] = this->get_db_ptr()->read_bbt_page(m_page_info[pos].second);
    }

    return m_child_pages[pos].get();
}

template<>
inline bt_page<node_id, node_info>* bt_nonleaf_page<node_id, node_info>::get_child(uint pos)
{
    if(m_child_pages[pos] == NULL)
    {
        m_child_pages[pos] = this->get_db_ptr()->read_nbt_page(m_page_info[pos].second); 
    }

    return m_child_pages[pos].get();
}

template<>
inline const bt_page<node_id, node_info>* bt_nonleaf_page<node_id, node_info>::get_child(uint pos) const
{
    if(m_child_pages[pos] == NULL)
    {
        m_child_pages[pos] = this->get_db_ptr()->read_nbt_page(m_page_info[pos].second); 
    }

    return m_child_pages[pos].get();
}
} // end namespace

#ifdef _MSC_VER
#pragma warning(pop)
#endif

#endif