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Eliminate some repetitive coding in tuplesort.c.
Use a macro LogicalTapeReadExact() to encapsulate the error check when we want to read an exact number of bytes from a "tape". Per a suggestion of Takahiro Itagaki.
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+32
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‎src/backend/utils/sort/tuplesort.c‎

Lines changed: 32 additions & 37 deletions
Original file line numberDiff line numberDiff line change
@@ -120,9 +120,9 @@
120120

121121

122122
/* sort-type codes for sort__start probes */
123-
#define HEAP_SORT 0
124-
#define INDEX_SORT 1
125-
#define DATUM_SORT 2
123+
#define HEAP_SORT 0
124+
#define INDEX_SORT 1
125+
#define DATUM_SORT 2
126126
#define CLUSTER_SORT 3
127127

128128
/* GUC variables */
@@ -435,6 +435,13 @@ struct Tuplesortstate
435435
* a lot better than what we were doing before 7.3.
436436
*/
437437

438+
/* When using this macro, beware of double evaluation of len */
439+
#define LogicalTapeReadExact(tapeset, tapenum, ptr, len) \
440+
do { \
441+
if (LogicalTapeRead(tapeset, tapenum, ptr, len) != (size_t) (len)) \
442+
elog(ERROR, "unexpected end of data"); \
443+
} while(0)
444+
438445

439446
static Tuplesortstate *tuplesort_begin_common(int workMem, bool randomAccess);
440447
static void puttuple_common(Tuplesortstate *state, SortTuple *tuple);
@@ -2576,8 +2583,8 @@ getlen(Tuplesortstate *state, int tapenum, bool eofOK)
25762583
{
25772584
unsigned int len;
25782585

2579-
if (LogicalTapeRead(state->tapeset, tapenum, (void *) &len,
2580-
sizeof(len)) != sizeof(len))
2586+
if (LogicalTapeRead(state->tapeset, tapenum,
2587+
&len, sizeof(len)) != sizeof(len))
25812588
elog(ERROR, "unexpected end of tape");
25822589
if (len == 0 && !eofOK)
25832590
elog(ERROR, "unexpected end of data");
@@ -2810,14 +2817,11 @@ readtup_heap(Tuplesortstate *state, SortTuple *stup,
28102817
USEMEM(state, GetMemoryChunkSpace(tuple));
28112818
/* read in the tuple proper */
28122819
tuple->t_len = tuplen;
2813-
if (LogicalTapeRead(state->tapeset, tapenum,
2814-
(void *) tupbody,
2815-
tupbodylen) != (size_t) tupbodylen)
2816-
elog(ERROR, "unexpected end of data");
2820+
LogicalTapeReadExact(state->tapeset, tapenum,
2821+
tupbody, tupbodylen);
28172822
if (state->randomAccess) /* need trailing length word? */
2818-
if (LogicalTapeRead(state->tapeset, tapenum, (void *) &tuplen,
2819-
sizeof(tuplen)) != sizeof(tuplen))
2820-
elog(ERROR, "unexpected end of data");
2823+
LogicalTapeReadExact(state->tapeset, tapenum,
2824+
&tuplen, sizeof(tuplen));
28212825
stup->tuple = (void *) tuple;
28222826
/* set up first-column key value */
28232827
htup.t_len = tuple->t_len + MINIMAL_TUPLE_OFFSET;
@@ -2998,20 +3002,16 @@ readtup_cluster(Tuplesortstate *state, SortTuple *stup,
29983002
/* Reconstruct the HeapTupleData header */
29993003
tuple->t_data = (HeapTupleHeader) ((char *) tuple + HEAPTUPLESIZE);
30003004
tuple->t_len = t_len;
3001-
if (LogicalTapeRead(state->tapeset, tapenum,
3002-
&tuple->t_self,
3003-
sizeof(ItemPointerData)) != sizeof(ItemPointerData))
3004-
elog(ERROR, "unexpected end of data");
3005+
LogicalTapeReadExact(state->tapeset, tapenum,
3006+
&tuple->t_self, sizeof(ItemPointerData));
30053007
/* We don't currently bother to reconstruct t_tableOid */
30063008
tuple->t_tableOid = InvalidOid;
30073009
/* Read in the tuple body */
3008-
if (LogicalTapeRead(state->tapeset, tapenum,
3009-
tuple->t_data, tuple->t_len) != tuple->t_len)
3010-
elog(ERROR, "unexpected end of data");
3010+
LogicalTapeReadExact(state->tapeset, tapenum,
3011+
tuple->t_data, tuple->t_len);
30113012
if (state->randomAccess) /* need trailing length word? */
3012-
if (LogicalTapeRead(state->tapeset, tapenum, &tuplen,
3013-
sizeof(tuplen)) != sizeof(tuplen))
3014-
elog(ERROR, "unexpected end of data");
3013+
LogicalTapeReadExact(state->tapeset, tapenum,
3014+
&tuplen, sizeof(tuplen));
30153015
stup->tuple = (void *) tuple;
30163016
/* set up first-column key value, if it's a simple column */
30173017
if (state->indexInfo->ii_KeyAttrNumbers[0] != 0)
@@ -3243,13 +3243,11 @@ readtup_index(Tuplesortstate *state, SortTuple *stup,
32433243
IndexTuple tuple = (IndexTuple) palloc(tuplen);
32443244

32453245
USEMEM(state, GetMemoryChunkSpace(tuple));
3246-
if (LogicalTapeRead(state->tapeset, tapenum, (void *) tuple,
3247-
tuplen) != tuplen)
3248-
elog(ERROR, "unexpected end of data");
3246+
LogicalTapeReadExact(state->tapeset, tapenum,
3247+
tuple, tuplen);
32493248
if (state->randomAccess) /* need trailing length word? */
3250-
if (LogicalTapeRead(state->tapeset, tapenum, (void *) &tuplen,
3251-
sizeof(tuplen)) != sizeof(tuplen))
3252-
elog(ERROR, "unexpected end of data");
3249+
LogicalTapeReadExact(state->tapeset, tapenum,
3250+
&tuplen, sizeof(tuplen));
32533251
stup->tuple = (void *) tuple;
32543252
/* set up first-column key value */
32553253
stup->datum1 = index_getattr(tuple,
@@ -3357,29 +3355,26 @@ readtup_datum(Tuplesortstate *state, SortTuple *stup,
33573355
else if (state->datumTypeByVal)
33583356
{
33593357
Assert(tuplen == sizeof(Datum));
3360-
if (LogicalTapeRead(state->tapeset, tapenum, (void *) &stup->datum1,
3361-
tuplen) != tuplen)
3362-
elog(ERROR, "unexpected end of data");
3358+
LogicalTapeReadExact(state->tapeset, tapenum,
3359+
&stup->datum1, tuplen);
33633360
stup->isnull1 = false;
33643361
stup->tuple = NULL;
33653362
}
33663363
else
33673364
{
33683365
void *raddr = palloc(tuplen);
33693366

3370-
if (LogicalTapeRead(state->tapeset, tapenum, raddr,
3371-
tuplen) != tuplen)
3372-
elog(ERROR, "unexpected end of data");
3367+
LogicalTapeReadExact(state->tapeset, tapenum,
3368+
raddr, tuplen);
33733369
stup->datum1 = PointerGetDatum(raddr);
33743370
stup->isnull1 = false;
33753371
stup->tuple = raddr;
33763372
USEMEM(state, GetMemoryChunkSpace(raddr));
33773373
}
33783374

33793375
if (state->randomAccess) /* need trailing length word? */
3380-
if (LogicalTapeRead(state->tapeset, tapenum, (void *) &tuplen,
3381-
sizeof(tuplen)) != sizeof(tuplen))
3382-
elog(ERROR, "unexpected end of data");
3376+
LogicalTapeReadExact(state->tapeset, tapenum,
3377+
&tuplen, sizeof(tuplen));
33833378
}
33843379

33853380
static void

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