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Commit 737651f

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author
Neil Conway
committed
Cleanup the usage of ScanDirection: use the symbolic names for the
possible ScanDirection alternatives rather than magic numbers (-1, 0, 1). Also, use the ScanDirection macros in a few places rather than directly checking whether `dir == ForwardScanDirection' and the like. Per patch from James William Pye. His patch also changed ScanDirection to be a "char" rather than an enum, which I haven't applied.
1 parent 3666260 commit 737651f

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3 files changed

+30
-48
lines changed

3 files changed

+30
-48
lines changed

‎src/backend/access/heap/heapam.c

Lines changed: 23 additions & 41 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.206 2006/01/11 08:43:11 neilc Exp $
11+
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.207 2006/02/21 23:01:53 neilc Exp $
1212
*
1313
*
1414
* INTERFACE ROUTINES
@@ -172,7 +172,8 @@ heapgetpage(HeapScanDesc scan, BlockNumber page)
172172
* tuple as indicated by "dir"; return the next tuple in scan->rs_ctup,
173173
* or set scan->rs_ctup.t_data = NULL if no more tuples.
174174
*
175-
* dir == 0 means "re-fetch the tuple indicated by scan->rs_ctup".
175+
* dir == NoMovementScanDirection means "re-fetch the tuple indicated
176+
* by scan->rs_ctup".
176177
*
177178
* Note: the reason nkeys/key are passed separately, even though they are
178179
* kept in the scan descriptor, is that the caller may not want us to check
@@ -189,12 +190,13 @@ heapgetpage(HeapScanDesc scan, BlockNumber page)
189190
*/
190191
static void
191192
heapgettup(HeapScanDesc scan,
192-
int dir,
193+
ScanDirection dir,
193194
int nkeys,
194195
ScanKey key)
195196
{
196197
HeapTuple tuple = &(scan->rs_ctup);
197198
Snapshot snapshot = scan->rs_snapshot;
199+
bool backward = ScanDirectionIsBackward(dir);
198200
BlockNumber page;
199201
Page dp;
200202
int lines;
@@ -205,11 +207,8 @@ heapgettup(HeapScanDesc scan,
205207
/*
206208
* calculate next starting lineoff, given scan direction
207209
*/
208-
if (dir > 0)
210+
if (ScanDirectionIsForward(dir))
209211
{
210-
/*
211-
* forward scan direction
212-
*/
213212
if (!scan->rs_inited)
214213
{
215214
/*
@@ -242,11 +241,8 @@ heapgettup(HeapScanDesc scan,
242241

243242
linesleft = lines - lineoff + 1;
244243
}
245-
else if (dir < 0)
244+
else if (backward)
246245
{
247-
/*
248-
* reverse scan direction
249-
*/
250246
if (!scan->rs_inited)
251247
{
252248
/*
@@ -352,7 +348,7 @@ heapgettup(HeapScanDesc scan,
352348
* otherwise move to the next item on the page
353349
*/
354350
--linesleft;
355-
if (dir < 0)
351+
if (backward)
356352
{
357353
--lpp; /* move back in this page's ItemId array */
358354
--lineoff;
@@ -373,7 +369,7 @@ heapgettup(HeapScanDesc scan,
373369
/*
374370
* return NULL if we've exhausted all the pages
375371
*/
376-
if ((dir < 0) ? (page == 0) : (page + 1 >= scan->rs_nblocks))
372+
if (backward ? (page == 0) : (page + 1 >= scan->rs_nblocks))
377373
{
378374
if (BufferIsValid(scan->rs_cbuf))
379375
ReleaseBuffer(scan->rs_cbuf);
@@ -384,7 +380,7 @@ heapgettup(HeapScanDesc scan,
384380
return;
385381
}
386382

387-
page = (dir < 0) ? (page - 1) : (page + 1);
383+
page = backward ? (page - 1) : (page + 1);
388384

389385
heapgetpage(scan, page);
390386

@@ -393,7 +389,7 @@ heapgettup(HeapScanDesc scan,
393389
dp = (Page) BufferGetPage(scan->rs_cbuf);
394390
lines = PageGetMaxOffsetNumber((Page) dp);
395391
linesleft = lines;
396-
if (dir < 0)
392+
if (backward)
397393
{
398394
lineoff = lines;
399395
lpp = PageGetItemId(dp, lines);
@@ -421,11 +417,12 @@ heapgettup(HeapScanDesc scan,
421417
*/
422418
static void
423419
heapgettup_pagemode(HeapScanDesc scan,
424-
int dir,
420+
ScanDirection dir,
425421
int nkeys,
426422
ScanKey key)
427423
{
428424
HeapTuple tuple = &(scan->rs_ctup);
425+
bool backward = ScanDirectionIsBackward(dir);
429426
BlockNumber page;
430427
Page dp;
431428
int lines;
@@ -437,11 +434,8 @@ heapgettup_pagemode(HeapScanDesc scan,
437434
/*
438435
* calculate next starting lineindex, given scan direction
439436
*/
440-
if (dir > 0)
437+
if (ScanDirectionIsForward(dir))
441438
{
442-
/*
443-
* forward scan direction
444-
*/
445439
if (!scan->rs_inited)
446440
{
447441
/*
@@ -471,11 +465,8 @@ heapgettup_pagemode(HeapScanDesc scan,
471465

472466
linesleft = lines - lineindex;
473467
}
474-
else if (dir < 0)
468+
else if (backward)
475469
{
476-
/*
477-
* reverse scan direction
478-
*/
479470
if (!scan->rs_inited)
480471
{
481472
/*
@@ -584,14 +575,10 @@ heapgettup_pagemode(HeapScanDesc scan,
584575
* otherwise move to the next item on the page
585576
*/
586577
--linesleft;
587-
if (dir < 0)
588-
{
578+
if (backward)
589579
--lineindex;
590-
}
591580
else
592-
{
593581
++lineindex;
594-
}
595582
}
596583

597584
/*
@@ -602,7 +589,7 @@ heapgettup_pagemode(HeapScanDesc scan,
602589
/*
603590
* return NULL if we've exhausted all the pages
604591
*/
605-
if ((dir < 0) ? (page == 0) : (page + 1 >= scan->rs_nblocks))
592+
if (backward ? (page == 0) : (page + 1 >= scan->rs_nblocks))
606593
{
607594
if (BufferIsValid(scan->rs_cbuf))
608595
ReleaseBuffer(scan->rs_cbuf);
@@ -613,14 +600,13 @@ heapgettup_pagemode(HeapScanDesc scan,
613600
return;
614601
}
615602

616-
page = (dir < 0) ? (page - 1) : (page + 1);
617-
603+
page = backward ? (page - 1) : (page + 1);
618604
heapgetpage(scan, page);
619605

620606
dp = (Page) BufferGetPage(scan->rs_cbuf);
621607
lines = scan->rs_ntuples;
622608
linesleft = lines;
623-
if (dir < 0)
609+
if (backward)
624610
lineindex = lines - 1;
625611
else
626612
lineindex = 0;
@@ -1008,15 +994,11 @@ heap_getnext(HeapScanDesc scan, ScanDirection direction)
1008994

1009995
HEAPDEBUG_1; /* heap_getnext( info ) */
1010996

1011-
/*
1012-
* Note: we depend here on the -1/0/1 encoding of ScanDirection.
1013-
*/
1014997
if (scan->rs_pageatatime)
1015-
heapgettup_pagemode(scan, (int) direction,
998+
heapgettup_pagemode(scan, direction,
1016999
scan->rs_nkeys, scan->rs_key);
10171000
else
1018-
heapgettup(scan, (int) direction,
1019-
scan->rs_nkeys, scan->rs_key);
1001+
heapgettup(scan, direction, scan->rs_nkeys, scan->rs_key);
10201002

10211003
if (scan->rs_ctup.t_data == NULL)
10221004
{
@@ -2745,13 +2727,13 @@ heap_restrpos(HeapScanDesc scan)
27452727
{
27462728
scan->rs_cindex = scan->rs_mindex;
27472729
heapgettup_pagemode(scan,
2748-
0, /* "no movement" */
2730+
NoMovementScanDirection,
27492731
0, /* needn't recheck scan keys */
27502732
NULL);
27512733
}
27522734
else
27532735
heapgettup(scan,
2754-
0, /* "no movement" */
2736+
NoMovementScanDirection,
27552737
0, /* needn't recheck scan keys */
27562738
NULL);
27572739
}

‎src/backend/executor/execMain.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -26,7 +26,7 @@
2626
*
2727
*
2828
* IDENTIFICATION
29-
* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.266 2006/02/19 00:04:26 neilc Exp $
29+
* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.267 2006/02/21 23:01:54 neilc Exp $
3030
*
3131
*-------------------------------------------------------------------------
3232
*/
@@ -218,7 +218,7 @@ ExecutorRun(QueryDesc *queryDesc,
218218
/*
219219
* run plan
220220
*/
221-
if (direction == NoMovementScanDirection)
221+
if (ScanDirectionIsNoMovement(direction))
222222
result = NULL;
223223
else
224224
result = ExecutePlan(estate,

‎src/backend/tcop/pquery.c

Lines changed: 5 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.98 2005/11/22 18:17:21 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.99 2006/02/21 23:01:54 neilc Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -795,7 +795,7 @@ PortalRunSelect(Portal portal,
795795
nprocessed = queryDesc->estate->es_processed;
796796
}
797797

798-
if (direction != NoMovementScanDirection)
798+
if (!ScanDirectionIsNoMovement(direction))
799799
{
800800
long oldPos;
801801

@@ -837,7 +837,7 @@ PortalRunSelect(Portal portal,
837837
nprocessed = queryDesc->estate->es_processed;
838838
}
839839

840-
if (direction != NoMovementScanDirection)
840+
if (!ScanDirectionIsNoMovement(direction))
841841
{
842842
if (nprocessed > 0 && portal->atEnd)
843843
{
@@ -890,13 +890,13 @@ RunFromStore(Portal portal, ScanDirection direction, long count,
890890

891891
(*dest->rStartup) (dest, CMD_SELECT, portal->tupDesc);
892892

893-
if (direction == NoMovementScanDirection)
893+
if (ScanDirectionIsNoMovement(direction))
894894
{
895895
/* do nothing except start/stop the destination */
896896
}
897897
else
898898
{
899-
bool forward = (direction == ForwardScanDirection);
899+
bool forward = ScanDirectionIsForward(direction);
900900

901901
for (;;)
902902
{

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