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

Copyright (c) 2013, 2021, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation.  The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License, version 2.0, for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

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

/******************************************************************//**
@file include/sync0policy.h
Policies for mutexes.

Created 2012-08-21 Sunny Bains.
***********************************************************************/

#ifndef sync0policy_h
#define sync0policy_h

#include "univ.i"
#include "ut0rnd.h"
#include "os0thread.h"
#include "sync0types.h"
#include "srv0mon.h"

#ifdef UNIV_DEBUG

# define MUTEX_MAGIC_N 979585UL

template <typename Mutex>
class MutexDebug {
public:

	/** For passing context to SyncDebug */
	struct Context : public latch_t {

		/** Constructor */
		Context()
			:
			m_mutex(),
			m_filename(),
			m_line(),
			m_thread_id(os_thread_id_t(ULINT_UNDEFINED))
		{
			/* No op */
		}

		/** Create the context for SyncDebug
		@param[in]	id	ID of the latch to track */
		Context(latch_id_t id)
			:
			latch_t(id)
		{
			/* No op */
		}

		/** Set to locked state
		@param[in]	mutex		The mutex to acquire
		@param[in]	filename	File name from where to acquire
		@param[in]	line		Line number in filename */
		void locked(
			const Mutex*		mutex,
			const char*		filename,
			ulint			line)
			UNIV_NOTHROW
		{
			m_mutex = mutex;

			m_thread_id = os_thread_get_curr_id();

			m_filename = filename;

			m_line = line;
		}

		/** Reset to unlock state */
		void release()
			UNIV_NOTHROW
		{
			m_mutex = NULL;

			m_thread_id = os_thread_id_t(ULINT_UNDEFINED);

			m_filename = NULL;

			m_line = ULINT_UNDEFINED;
		}

		/** Print information about the latch
		@return the string representation */
		virtual std::string to_string() const
			UNIV_NOTHROW
		{
			std::ostringstream msg;

			msg << m_mutex->policy().to_string();

			if (os_thread_pf(m_thread_id) != ULINT_UNDEFINED) {

				msg << " addr: " << m_mutex
				    << " acquired: " << locked_from().c_str();

			} else {
				msg << "Not locked";
			}

			return(msg.str());
		}

		/** @return the name of the file and line number in the file
		from where the mutex was acquired "filename:line" */
		virtual std::string locked_from() const
		{
			std::ostringstream msg;

			msg << sync_basename(m_filename) << ":" << m_line;

			return(std::string(msg.str()));
		}

		/** Mutex to check for lock order violation */
		const Mutex*	m_mutex;

		/** Filename from where enter was called */
		const char*	m_filename;

		/** Line mumber in filename */
		ulint		m_line;

		/** Thread ID of the thread that own(ed) the mutex */
		os_thread_id_t	m_thread_id;
	};

	/** Constructor. */
	MutexDebug()
		:
		m_magic_n(),
		m_context()
		UNIV_NOTHROW
	{
		/* No op */
	}

	/* Destructor */
	virtual ~MutexDebug() { }

	/** Mutex is being destroyed. */
	void destroy() UNIV_NOTHROW
	{
		ut_ad(m_context.m_thread_id == os_thread_id_t(ULINT_UNDEFINED));

		m_magic_n = 0;

		m_context.m_thread_id = 0;
	}

	/** Called when the mutex is "created". Note: Not from the constructor
	but when the mutex is initialised.
	@param[in]	id              Mutex ID */
	void init(latch_id_t id)
		UNIV_NOTHROW;

	/** Called when an attempt is made to lock the mutex
	@param[in]	mutex		Mutex instance to be locked
	@param[in]	filename	Filename from where it was called
	@param[in]	line		Line number from where it was called */
	void enter(
		const Mutex*	mutex,
		const char*	filename,
		ulint		line)
		UNIV_NOTHROW;

	/** Called when the mutex is locked
	@param[in]	mutex		Mutex instance that was locked
	@param[in]	filename	Filename from where it was called
	@param[in]	line		Line number from where it was called */
	void locked(
		const Mutex*	mutex,
		const char*	filename,
		ulint		line)
		UNIV_NOTHROW;

	/** Called when the mutex is released
	@param[in]	mutx		Mutex that was released */
	void release(const Mutex* mutex)
		UNIV_NOTHROW;

	/** @return true if thread owns the mutex */
	bool is_owned() const UNIV_NOTHROW
	{
		return(os_thread_eq(
				m_context.m_thread_id,
				os_thread_get_curr_id()));
	}

	/** @return the name of the file from the mutex was acquired */
	const char* get_enter_filename() const
		UNIV_NOTHROW
	{
		return(m_context.m_filename);
	}

	/** @return the name of the file from the mutex was acquired */
	ulint get_enter_line() const
		UNIV_NOTHROW
	{
		return(m_context.m_line);
	}

	/** @return id of the thread that was trying to acquire the mutex */
	os_thread_id_t get_thread_id() const
		UNIV_NOTHROW
	{
		return(m_context.m_thread_id);
	}

	/** Magic number to check for memory corruption. */
	ulint			m_magic_n;

	/** Latch state of the mutex owner */
	Context			m_context;
};
#endif /* UNIV_DEBUG */

/* Do nothing */
template <typename Mutex>
struct NoPolicy {
	/** Default constructor. */
	NoPolicy() { }

	void init(const Mutex&, latch_id_t, const char*, uint32_t)
		UNIV_NOTHROW { }
	void destroy() UNIV_NOTHROW { }
	void enter(const Mutex&, const char*, ulint line) UNIV_NOTHROW { }
	void add(uint32_t, uint32_t) UNIV_NOTHROW { }
	void locked(const Mutex&, const char*, ulint) UNIV_NOTHROW { }
	void release(const Mutex&) UNIV_NOTHROW { }
	std::string to_string() const { return(""); };
	latch_id_t get_id() const;
};

/** Collect the metrics per mutex instance, no aggregation. */
template <typename Mutex>
struct GenericPolicy
#ifdef UNIV_DEBUG
: public MutexDebug<Mutex>
#endif /* UNIV_DEBUG */
{
public:
	typedef Mutex MutexType;

	/** Constructor. */
	GenericPolicy()
		UNIV_NOTHROW
		:
#ifdef UNIV_DEBUG
		MutexDebug<MutexType>(),
#endif /* UNIV_DEBUG */
		m_count(),
		m_id()
		{ }

	/** Destructor */
	~GenericPolicy() { }

	/** Called when the mutex is "created". Note: Not from the constructor
	but when the mutex is initialised.
	@param[in]	mutex		Mutex instance to track
	@param[in]	id              Mutex ID
	@param[in]	filename	File where mutex was created
	@param[in]	line		Line in filename */
	void init(
		const MutexType&	mutex,
		latch_id_t		id,
		const char*		filename,
		uint32_t		line)
		UNIV_NOTHROW
	{
		m_id = id;

		latch_meta_t&	meta = sync_latch_get_meta(id);

		ut_ad(meta.get_id() == id);

		meta.get_counter()->single_register(&m_count);

		sync_file_created_register(this, filename, line);

		ut_d(MutexDebug<MutexType>::init(m_id));
	}

	/** Called when the mutex is destroyed. */
	void destroy()
		UNIV_NOTHROW
	{
		latch_meta_t&	meta = sync_latch_get_meta(m_id);

		meta.get_counter()->single_deregister(&m_count);

		sync_file_created_deregister(this);

		ut_d(MutexDebug<MutexType>::destroy());
	}

	/** Called after a successful mutex acquire.
	@param[in]	n_spins		Number of times the thread did
					spins while trying to acquire the mutex
	@param[in]	n_waits		Number of times the thread waited
					in some type of OS queue */
	void add(
		uint32_t	n_spins,
		uint32_t	n_waits)
		UNIV_NOTHROW
	{
		/* Currently global on/off. Keeps things simple and fast */

		if (!m_count.m_enabled) {

			return;
		}

		m_count.m_spins += n_spins;
		m_count.m_waits += n_waits;

		++m_count.m_calls;
	}

	/** Called when an attempt is made to lock the mutex
	@param[in]	mutex		Mutex instance to be locked
	@param[in]	filename	Filename from where it was called
	@param[in]	line		Line number from where it was called */
	void enter(
		const MutexType&	mutex,
		const char*		filename,
		ulint			line)
		UNIV_NOTHROW
	{
		ut_d(MutexDebug<MutexType>::enter(&mutex, filename, line));
	}

	/** Called when the mutex is locked
	@param[in]	mutex		Mutex instance that is locked
	@param[in]	filename	Filename from where it was called
	@param[in]	line		Line number from where it was called */
	void locked(
		const MutexType&	mutex,
		const char*		filename,
		ulint			line)
		UNIV_NOTHROW
	{
		ut_d(MutexDebug<MutexType>::locked(&mutex, filename, line));
	}

	/** Called when the mutex is released
	@param[in]	mutex		Mutex instance that is released */
	void release(const MutexType& mutex)
		UNIV_NOTHROW
	{
		ut_d(MutexDebug<MutexType>::release(&mutex));
	}

	/** Print the information about the latch
	@return the string representation */
	std::string print() const
		UNIV_NOTHROW;

	/** @return the latch ID */
	latch_id_t get_id() const
		UNIV_NOTHROW
	{
		return(m_id);
	}

	/** @return the string representation */
	std::string to_string() const;

private:
	typedef latch_meta_t::CounterType Counter;

	/** The user visible counters, registered with the meta-data.  */
	Counter::Count		m_count;

	/** Latch meta data ID */
	latch_id_t		m_id;
};

/** Track agregate metrics policy, used by the page mutex. There are just
too many of them to count individually. */
template <typename Mutex>
class BlockMutexPolicy
#ifdef UNIV_DEBUG
: public MutexDebug<Mutex>
#endif /* UNIV_DEBUG */
{
public:
	typedef Mutex MutexType;
	typedef typename latch_meta_t::CounterType::Count Count;

	/** Default constructor. */
	BlockMutexPolicy()
		:
#ifdef UNIV_DEBUG
		MutexDebug<MutexType>(),
#endif /* UNIV_DEBUG */
		m_count(),
		m_id()
	{
		/* Do nothing */
	}

	/** Destructor */
	~BlockMutexPolicy() { }

	/** Called when the mutex is "created". Note: Not from the constructor
	but when the mutex is initialised.
	@param[in]	mutex		Mutex instance to track
	@param[in]	id              Mutex ID
	@param[in]	filename	File where mutex was created
	@param[in]	line		Line in filename */
	void init(
		const MutexType&	mutex,
		latch_id_t		id,
		const char*		filename,
		uint32_t		line)
		UNIV_NOTHROW
	{
		/* It can be LATCH_ID_BUF_BLOCK_MUTEX or
		LATCH_ID_BUF_POOL_ZIP. Unfortunately, they
		are mapped to the same mutex type in the
		buffer pool code. */

		m_id = id;

		latch_meta_t&	meta = sync_latch_get_meta(m_id);

		ut_ad(meta.get_id() == id);

		m_count = meta.get_counter()->sum_register();

		ut_d(MutexDebug<MutexType>::init(m_id));
	}

	/** Called when the mutex is destroyed. */
	void destroy()
		UNIV_NOTHROW
	{
		latch_meta_t&	meta = sync_latch_get_meta(m_id);

		ut_ad(meta.get_id() == m_id);

		meta.get_counter()->sum_deregister(m_count);

		m_count = NULL;

		ut_d(MutexDebug<MutexType>::destroy());
	}

	/** Called after a successful mutex acquire.
	@param[in]	n_spins		Number of times the thread did
					spins while trying to acquire the mutex
	@param[in]	n_waits		Number of times the thread waited
					in some type of OS queue */
	void add(
		uint32_t	n_spins,
		uint32_t	n_waits)
		UNIV_NOTHROW
	{
		if (!m_count->m_enabled) {

			return;
		}

		m_count->m_spins += n_spins;
		m_count->m_waits += n_waits;

		++m_count->m_calls;
	}

	/** Called when the mutex is locked
	@param[in]	mutex		Mutex instance that is locked
	@param[in]	filename	Filename from where it was called
	@param[in]	line		Line number from where it was called */
	void locked(
		const MutexType&	mutex,
		const char*		filename,
		ulint			line)
		UNIV_NOTHROW
	{
		ut_d(MutexDebug<MutexType>::locked(&mutex, filename, line));
	}

	/** Called when the mutex is released
	@param[in]	mutex		Mutex instance that is released */
	void release(const MutexType& mutex)
		UNIV_NOTHROW
	{
		ut_d(MutexDebug<MutexType>::release(&mutex));
	}

	/** Called when an attempt is made to lock the mutex
	@param[in]	mutex		Mutex instance to be locked
	@param[in]	filename	Filename from where it was called
	@param[in]	line		Line number from where it was called */
	void enter(
		const MutexType&	mutex,
		const char*		filename,
		ulint			line)
		UNIV_NOTHROW
	{
		ut_d(MutexDebug<MutexType>::enter(&mutex, filename, line));
	}

	/** Print the information about the latch
	@return the string representation */
	std::string print() const
		UNIV_NOTHROW;

	/** @return the latch ID */
	latch_id_t get_id() const
	{
		return(m_id);
	}

	/** @return the string representation */
	std::string to_string() const;

private:
	typedef latch_meta_t::CounterType Counter;

	/** The user visible counters, registered with the meta-data.  */
	Counter::Count*		m_count;

	/** Latch meta data ID */
	latch_id_t		m_id;
};

#ifndef UNIV_NONINL
#include "sync0policy.ic"
#endif /* UNIV_NOINL */

#endif /* sync0policy_h */
