database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-04 20:11:56 +03:00
Code Activity

Static assertions cleanup

Browse Source 
Because we added StaticAssertStmt() first before StaticAssertDecl(),
some uses as well as the instructions in c.h are now a bit backwards
from the "native" way static assertions are meant to be used in C.
This updates the guidance and moves some static assertions to better
places.

Specifically, since the addition of StaticAssertDecl(), we can put
static assertions at the file level.  This moves a number of static
assertions out of function bodies, where they might have been stuck
out of necessity, to perhaps better places at the file level or in
header files.

Also, when the static assertion appears in a position where a
declaration is allowed, then using StaticAssertDecl() is more native
than StaticAssertStmt().

Reviewed-by: John Naylor <john.naylor@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/941a04e7-dd6f-c0e4-8cdf-a33b3338cbda%40enterprisedb.com
This commit is contained in:
Peter Eisentraut
2022-12-08 14:30:01 +01:00
parent 2613dec4ed
commit 75f49221c2
29 changed files with 99 additions and 104 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
src/backend/utils/adt/xid8funcs.c
View File

@@ -74,6 +74,14 @@ typedef struct
#define PG_SNAPSHOT_MAX_NXIP \
((MaxAllocSize - offsetof(pg_snapshot, xip)) / sizeof(FullTransactionId))
/*
* Compile-time limits on the procarray (MAX_BACKENDS processes plus
* MAX_BACKENDS prepared transactions) guarantee nxip won't be too large.
*/
StaticAssertDecl(MAX_BACKENDS * 2 <= PG_SNAPSHOT_MAX_NXIP,
"possible overflow in pg_current_snapshot()");
/*
* Helper to get a TransactionId from a 64-bit xid with wraparound detection.
*
@@ -402,13 +410,6 @@ pg_current_snapshot(PG_FUNCTION_ARGS)
if (cur == NULL)
elog(ERROR, "no active snapshot set");
/*
* Compile-time limits on the procarray (MAX_BACKENDS processes plus
* MAX_BACKENDS prepared transactions) guarantee nxip won't be too large.
*/
StaticAssertStmt(MAX_BACKENDS * 2 <= PG_SNAPSHOT_MAX_NXIP,
"possible overflow in pg_current_snapshot()");
/* allocate */
nxip = cur->xcnt;
snap = palloc(PG_SNAPSHOT_SIZE(nxip));