/******************************************************
Mini-transaction logging routines

(c) 1995 Innobase Oy

Created 12/7/1995 Heikki Tuuri
*******************************************************/

#include "mach0data.h"
#include "ut0lst.h"
#include "buf0buf.h"

/************************************************************
Opens a buffer to mlog. It must be closed with mlog_close. */
UNIV_INLINE
byte*
mlog_open(
/*======*/
			/* out: buffer, NULL if log mode MTR_LOG_NONE */
	mtr_t*	mtr,	/* in: mtr */
	ulint	size)	/* in: buffer size in bytes; MUST be
			smaller than DYN_ARRAY_DATA_SIZE! */
{
	dyn_array_t*	mlog;

	mtr->modifications = TRUE;

	if (mtr_get_log_mode(mtr) == MTR_LOG_NONE) {

		return(NULL);
	}

	mlog = &(mtr->log);

	return(dyn_array_open(mlog, size));
}

/************************************************************
Closes a buffer opened to mlog. */
UNIV_INLINE
void
mlog_close(
/*=======*/
	mtr_t*	mtr,	/* in: mtr */
	byte*	ptr)	/* in: buffer space from ptr up was not used */
{
	dyn_array_t*	mlog;

	ut_ad(mtr_get_log_mode(mtr) != MTR_LOG_NONE);

	mlog = &(mtr->log);

	dyn_array_close(mlog, ptr);
}

/************************************************************
Catenates 1 - 4 bytes to the mtr log. The value is not compressed. */
UNIV_INLINE
void
mlog_catenate_ulint(
/*================*/
	mtr_t*	mtr,	/* in: mtr */
	ulint	val,	/* in: value to write */
	ulint	type)	/* in: MLOG_1BYTE, MLOG_2BYTES, MLOG_4BYTES */
{
	dyn_array_t*	mlog;
	byte*		ptr;

	if (mtr_get_log_mode(mtr) == MTR_LOG_NONE) {

		return;
	}

	mlog = &(mtr->log);

	ut_ad(MLOG_1BYTE == 1);
	ut_ad(MLOG_2BYTES == 2);
	ut_ad(MLOG_4BYTES == 4);

	ptr = dyn_array_push(mlog, type);

	if (type == MLOG_4BYTES) {
		mach_write_to_4(ptr, val);
	} else if (type == MLOG_2BYTES) {
		mach_write_to_2(ptr, val);
	} else {
		ut_ad(type == MLOG_1BYTE);
		mach_write_to_1(ptr, val);
 	}
}

/************************************************************
Catenates a compressed ulint to mlog. */
UNIV_INLINE
void
mlog_catenate_ulint_compressed(
/*===========================*/
	mtr_t*	mtr,	/* in: mtr */
	ulint	val)	/* in: value to write */
{
	byte*	log_ptr;

	log_ptr = mlog_open(mtr, 10);

	/* If no logging is requested, we may return now */
	if (log_ptr == NULL) {

		return;
	}

	log_ptr += mach_write_compressed(log_ptr, val);

	mlog_close(mtr, log_ptr);
}

/************************************************************
Catenates a compressed dulint to mlog. */
UNIV_INLINE
void
mlog_catenate_dulint_compressed(
/*============================*/
	mtr_t*	mtr,	/* in: mtr */
	dulint	val)	/* in: value to write */
{
	byte*	log_ptr;

	log_ptr = mlog_open(mtr, 15);

	/* If no logging is requested, we may return now */
	if (log_ptr == NULL) {

		return;
	}

	log_ptr += mach_dulint_write_compressed(log_ptr, val);

	mlog_close(mtr, log_ptr);
}

/************************************************************
Writes the initial part of a log record (3..11 bytes).
If the implementation of this function is changed, all
size parameters to mlog_open() should be adjusted accordingly! */
UNIV_INLINE
byte*
mlog_write_initial_log_record_fast(
/*===============================*/
			/* out: new value of log_ptr */
	byte*	ptr,	/* in: pointer to (inside) a buffer frame holding the
			file page where modification is made */
	byte	type,	/* in: log item type: MLOG_1BYTE, ... */
	byte*	log_ptr,/* in: pointer to mtr log which has been opened */
	mtr_t*	mtr)	/* in: mtr */
{
	buf_block_t*	block;
	ulint		space;
	ulint		offset;

	ut_ad(mtr_memo_contains(mtr, buf_block_align(ptr), 
							MTR_MEMO_PAGE_X_FIX));
	ut_ad(type <= MLOG_BIGGEST_TYPE);
	ut_ad(ptr && log_ptr);

	block = buf_block_align(ptr);

	space = buf_block_get_space(block);
	offset = buf_block_get_page_no(block);

	mach_write_to_1(log_ptr, type);
	log_ptr++;	
	log_ptr += mach_write_compressed(log_ptr, space);
	log_ptr += mach_write_compressed(log_ptr, offset);

	mtr->n_log_recs++;

#ifdef UNIV_LOG_DEBUG
/*	fprintf(stderr,
		"Adding to mtr log record type %lu space %lu page no %lu\n",
						type, space, offset); */
#endif

#ifdef UNIV_DEBUG
	/* We now assume that all x-latched pages have been modified! */

	if (!mtr_memo_contains(mtr, block, MTR_MEMO_MODIFY)) {

		mtr_memo_push(mtr, block, MTR_MEMO_MODIFY);
	}
#endif
	return(log_ptr);
}	

/************************************************************
Writes a log record about an .ibd file create/delete/rename. */
UNIV_INLINE
byte*
mlog_write_initial_log_record_for_file_op(
/*======================================*/
			/* out: new value of log_ptr */
	ulint	type,	/* in: MLOG_FILE_CREATE, MLOG_FILE_DELETE, or
			MLOG_FILE_RENAME */
	ulint	space_id,/* in: space id, if applicable */
	ulint	page_no,/* in: page number (not relevant currently) */
	byte*	log_ptr,/* in: pointer to mtr log which has been opened */
	mtr_t*	mtr)	/* in: mtr */
{
	ut_ad(log_ptr);

	mach_write_to_1(log_ptr, type);
	log_ptr++;

	/* We write dummy space id and page number */
	log_ptr += mach_write_compressed(log_ptr, space_id);
	log_ptr += mach_write_compressed(log_ptr, page_no);

	mtr->n_log_recs++;

	return(log_ptr);
}	
