fis-gtm/sr_port/gvcst_incr.c

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/****************************************************************
* *
* Copyright 2004, 2010 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include "mdef.h"
#include "gdsroot.h" /* needed for gdsfhead.h */
#include "gdsblk.h" /* needed for gdsfhead.h */
#include "gtm_facility.h" /* needed for gdsfhead.h */
#include "fileinfo.h" /* needed for gdsfhead.h */
#include "gdsbt.h" /* needed for gdsfhead.h */
#include "gdsfhead.h" /* needed for gvcst_protos.h */
#include "gdsblkops.h"
#include "filestruct.h"
#include "jnl.h"
#include "gdscc.h" /* needed for tp.h */
#include "gdskill.h" /* needed for tp.h */
#include "buddy_list.h" /* needed for tp.h */
#include "hashtab_int4.h" /* needed for tp.h */
#include "tp.h"
#include "mvalconv.h" /* for i2mval prototype for the MV_FORCE_MVAL macro */
#include "gvcst_protos.h" /* for gvcst_incr prototype */
GBLREF boolean_t in_gvcst_incr;
GBLREF mval increment_delta_mval;
GBLREF mval *post_incr_mval;
GBLREF sgm_info *sgm_info_ptr;
void gvcst_incr(mval *increment, mval *result)
{
assert(!in_gvcst_incr);
assert(MV_IS_NUMERIC(increment)); /* op_gvincr or gtcmtr_increment should have done the MV_FORCE_NUM before calling */
in_gvcst_incr = TRUE;
post_incr_mval = result;
/* it is possible (due to some optimizations in the compiler) that both the input parameters "increment" and "result"
* point to the same mval. if we pass "increment" and "result" as they are to gvcst_put, it is possible due to the code
* flow that gvcst_put needs to read the value of "increment" after it is done modifying "result" (it can do this by
* changing the global variable "post_incr_mval"). in this case it will read a bad value of "increment" (since it will
* now be reading the modified value of "result"). therefore we do not pass them as they are. Instead, since we are
* interested in only the numeric value of "increment", we take a copy of "increment" into an mval ("increment_delta_mval")
* and force it to be numeric. It is the address of this mval that is passed to gvcst_put. Any changes to "post_incr_mval"
* will not affect this mval so it is safe to read this anytime in gvcst_put. The mval "increment_delta_mval" is also
* used in gvincr_recompute_upd_array.
*/
increment_delta_mval = *increment;
/* Since we should be caring about just the numeric part, nullify the string part of the mval */
increment_delta_mval.str.len = 0;
gvcst_put(&increment_delta_mval);
assert(!in_gvcst_incr); /* should have been reset by gvcst_put */
in_gvcst_incr = FALSE; /* just in case it is not reset already by gvcst_put */
}