~drizzle-trunk/drizzle/development

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

Mini-transaction buffer

(c) 1995 Innobase Oy

Created 11/26/1995 Heikki Tuuri

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

#include "sync0sync.h"

#include "sync0rw.h"

#include "mach0data.h"

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

Starts a mini-transaction and creates a mini-transaction handle

and a buffer in the memory buffer given by the caller. */

UNIV_INLINE

mtr_t*

mtr_start(

/*======*/

			/* out: mtr buffer which also acts as

			the mtr handle */

	mtr_t*	mtr)	/* in: memory buffer for the mtr buffer */

{

	dyn_array_create(&(mtr->memo));

	dyn_array_create(&(mtr->log));

	mtr->log_mode = MTR_LOG_ALL;

	mtr->modifications = FALSE;

	mtr->n_log_recs = 0;

#ifdef UNIV_DEBUG

	mtr->state = MTR_ACTIVE;

	mtr->magic_n = MTR_MAGIC_N;

#endif

	return(mtr);

}

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

Pushes an object to an mtr memo stack. */

UNIV_INLINE

void

mtr_memo_push(

/*==========*/

	mtr_t*	mtr,	/* in: mtr */

	void*	object,	/* in: object */

	ulint	type)	/* in: object type: MTR_MEMO_S_LOCK, ... */

{

	dyn_array_t*		memo;

	mtr_memo_slot_t*	slot;

	ut_ad(object);

	ut_ad(type >= MTR_MEMO_PAGE_S_FIX);

	ut_ad(type <= MTR_MEMO_X_LOCK);

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	memo = &(mtr->memo);

	slot = dyn_array_push(memo, sizeof(mtr_memo_slot_t));

	slot->object = object;

	slot->type = type;

}

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

Sets and returns a savepoint in mtr. */

UNIV_INLINE

ulint

mtr_set_savepoint(

/*==============*/

			/* out: savepoint */

	mtr_t*	mtr)	/* in: mtr */

{

	dyn_array_t*	memo;

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	memo = &(mtr->memo);

	return(dyn_array_get_data_size(memo));

}

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

Releases the (index tree) s-latch stored in an mtr memo after a

savepoint. */

UNIV_INLINE

void

mtr_release_s_latch_at_savepoint(

/*=============================*/

	mtr_t*		mtr,		/* in: mtr */

	ulint		savepoint,	/* in: savepoint */

	rw_lock_t*	lock)		/* in: latch to release */

{

	mtr_memo_slot_t* slot;

	dyn_array_t*	memo;

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	ut_ad(mtr->state == MTR_ACTIVE);

	memo = &(mtr->memo);

	ut_ad(dyn_array_get_data_size(memo) > savepoint);

	slot = dyn_array_get_element(memo, savepoint);

	ut_ad(slot->object == lock);

	ut_ad(slot->type == MTR_MEMO_S_LOCK);

	rw_lock_s_unlock(lock);

	slot->object = NULL;

}

#ifdef UNIV_DEBUG

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

Checks if memo contains the given item. */

UNIV_INLINE

ibool

mtr_memo_contains(

/*==============*/

			/* out: TRUE if contains */

	mtr_t*	mtr,	/* in: mtr */

	void*	object,	/* in: object to search */

	ulint	type)	/* in: type of object */

{

	mtr_memo_slot_t* slot;

	dyn_array_t*	memo;

	ulint		offset;

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	memo = &(mtr->memo);

	offset = dyn_array_get_data_size(memo);

	while (offset > 0) {

		offset -= sizeof(mtr_memo_slot_t);

		slot = dyn_array_get_element(memo, offset);

		if ((object == slot->object) && (type == slot->type)) {

			return(TRUE);

		}

	}

	return(FALSE);

}

#endif /* UNIV_DEBUG */

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

Returns the log object of a mini-transaction buffer. */

UNIV_INLINE

dyn_array_t*

mtr_get_log(

/*========*/

			/* out: log */

	mtr_t*	mtr)	/* in: mini-transaction */

{

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	return(&(mtr->log));

}

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

Gets the logging mode of a mini-transaction. */

UNIV_INLINE

ulint

mtr_get_log_mode(

/*=============*/

			/* out: logging mode: MTR_LOG_NONE, ... */

	mtr_t*	mtr)	/* in: mtr */

{

	ut_ad(mtr);

	ut_ad(mtr->log_mode >= MTR_LOG_ALL);

	ut_ad(mtr->log_mode <= MTR_LOG_SHORT_INSERTS);

	return(mtr->log_mode);

}

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

Changes the logging mode of a mini-transaction. */

UNIV_INLINE

ulint

mtr_set_log_mode(

/*=============*/

			/* out: old mode */

	mtr_t*	mtr,	/* in: mtr */

	ulint	mode)	/* in: logging mode: MTR_LOG_NONE, ... */

{

	ulint	old_mode;

	ut_ad(mtr);

	ut_ad(mode >= MTR_LOG_ALL);

	ut_ad(mode <= MTR_LOG_SHORT_INSERTS);

	old_mode = mtr->log_mode;

	if ((mode == MTR_LOG_SHORT_INSERTS) && (old_mode == MTR_LOG_NONE)) {

		/* Do nothing */

	} else {

		mtr->log_mode = mode;

	}

	ut_ad(old_mode >= MTR_LOG_ALL);

	ut_ad(old_mode <= MTR_LOG_SHORT_INSERTS);

	return(old_mode);

}

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

Locks a lock in s-mode. */

UNIV_INLINE

void

mtr_s_lock_func(

/*============*/

	rw_lock_t*	lock,	/* in: rw-lock */

	const char*	file,	/* in: file name */

	ulint		line,	/* in: line number */

	mtr_t*		mtr)	/* in: mtr */

{

	ut_ad(mtr);

	ut_ad(lock);

	rw_lock_s_lock_func(lock, 0, file, line);

	mtr_memo_push(mtr, lock, MTR_MEMO_S_LOCK);

}

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

Locks a lock in x-mode. */

UNIV_INLINE

void

mtr_x_lock_func(

/*============*/

	rw_lock_t*	lock,	/* in: rw-lock */

	const char*	file,	/* in: file name */

	ulint		line,	/* in: line number */

	mtr_t*		mtr)	/* in: mtr */

{

	ut_ad(mtr);

	ut_ad(lock);

	rw_lock_x_lock_func(lock, 0, file, line);

	mtr_memo_push(mtr, lock, MTR_MEMO_X_LOCK);

}