/*****************************************************************************

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it under the terms of the GNU General Public License, version 2.0,
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*****************************************************************************/

/**************************************************//**
@file include/sess0sess.h
InnoDB session state tracker.
Multi file, shared, system tablespace implementation.

Created 2014-04-30 by Krunal Bauskar
*******************************************************/

#ifndef sess0sess_h
#define sess0sess_h

#include "univ.i"
#include "dict0mem.h"
#include "ut0new.h"

#include <map>

class dict_intrinsic_table_t {

public:
	/** Constructor
	@param[in,out]	handler		table handler. */
	dict_intrinsic_table_t(dict_table_t*	handler)
		:
		m_handler(handler)
	{
		/* Do nothing. */
	}

	/** Destructor */
	~dict_intrinsic_table_t()
	{
		m_handler = NULL;
	}

public:

	/* Table Handler holding other metadata information commonly needed
	for any table. */
	dict_table_t*				m_handler;
};

/** InnoDB private data that is cached in THD */
typedef std::map<
	std::string,
	dict_intrinsic_table_t*,
	std::less<std::string>,
	ut_allocator<std::pair<const std::string, dict_intrinsic_table_t*> > >
	table_cache_t;

class innodb_session_t {
public:
	/** Constructor */
	innodb_session_t()
		: m_trx(),
		  m_open_tables()
	{
		/* Do nothing. */
	}

	/** Destructor */
	~innodb_session_t()
	{
		m_trx = NULL;

		for (table_cache_t::iterator it = m_open_tables.begin();
		     it != m_open_tables.end();
		     ++it) {
			delete(it->second);
		}
	}

	/** Cache table handler.
	@param[in]	table_name	name of the table
	@param[in,out]	table		table handler to register */
	void register_table_handler(
		const char*	table_name,
		dict_table_t*	table)
	{
		ut_ad(lookup_table_handler(table_name) == NULL);
		m_open_tables.insert(table_cache_t::value_type(
			table_name, new dict_intrinsic_table_t(table)));
	}

	/** Lookup for table handler given table_name.
	@param[in]	table_name	name of the table to lookup */
	dict_table_t* lookup_table_handler(
		const char*	table_name)
	{
		table_cache_t::iterator it = m_open_tables.find(table_name);
		return((it == m_open_tables.end())
		       ? NULL : it->second->m_handler);
	}

	/** Remove table handler entry.
	@param[in]	table_name	name of the table to remove */
	void unregister_table_handler(
		const char*	table_name)
	{
		table_cache_t::iterator it = m_open_tables.find(table_name);
		if (it == m_open_tables.end()) {
			return;
		}

		delete(it->second);
		m_open_tables.erase(table_name);
	}

	/** Count of register table handler.
	@return number of register table handlers */
	uint count_register_table_handler() const
	{
		return(static_cast<uint>(m_open_tables.size()));
	}

public:

	/** transaction handler. */
	trx_t*		m_trx;

	/** Handler of tables that are created or open but not added
	to InnoDB dictionary as they are session specific.
	Currently, limited to intrinsic temporary tables only. */
	table_cache_t	m_open_tables;
};


#endif /* sess0sess_h */