1 | /*------------------------------------------------------------------------- |
2 | * |
3 | * heaptuple.c |
4 | * This file contains heap tuple accessor and mutator routines, as well |
5 | * as various tuple utilities. |
6 | * |
7 | * Some notes about varlenas and this code: |
8 | * |
9 | * Before Postgres 8.3 varlenas always had a 4-byte length header, and |
10 | * therefore always needed 4-byte alignment (at least). This wasted space |
11 | * for short varlenas, for example CHAR(1) took 5 bytes and could need up to |
12 | * 3 additional padding bytes for alignment. |
13 | * |
14 | * Now, a short varlena (up to 126 data bytes) is reduced to a 1-byte header |
15 | * and we don't align it. To hide this from datatype-specific functions that |
16 | * don't want to deal with it, such a datum is considered "toasted" and will |
17 | * be expanded back to the normal 4-byte-header format by pg_detoast_datum. |
18 | * (In performance-critical code paths we can use pg_detoast_datum_packed |
19 | * and the appropriate access macros to avoid that overhead.) Note that this |
20 | * conversion is performed directly in heap_form_tuple, without invoking |
21 | * tuptoaster.c. |
22 | * |
23 | * This change will break any code that assumes it needn't detoast values |
24 | * that have been put into a tuple but never sent to disk. Hopefully there |
25 | * are few such places. |
26 | * |
27 | * Varlenas still have alignment 'i' (or 'd') in pg_type/pg_attribute, since |
28 | * that's the normal requirement for the untoasted format. But we ignore that |
29 | * for the 1-byte-header format. This means that the actual start position |
30 | * of a varlena datum may vary depending on which format it has. To determine |
31 | * what is stored, we have to require that alignment padding bytes be zero. |
32 | * (Postgres actually has always zeroed them, but now it's required!) Since |
33 | * the first byte of a 1-byte-header varlena can never be zero, we can examine |
34 | * the first byte after the previous datum to tell if it's a pad byte or the |
35 | * start of a 1-byte-header varlena. |
36 | * |
37 | * Note that while formerly we could rely on the first varlena column of a |
38 | * system catalog to be at the offset suggested by the C struct for the |
39 | * catalog, this is now risky: it's only safe if the preceding field is |
40 | * word-aligned, so that there will never be any padding. |
41 | * |
42 | * We don't pack varlenas whose attstorage is 'p', since the data type |
43 | * isn't expecting to have to detoast values. This is used in particular |
44 | * by oidvector and int2vector, which are used in the system catalogs |
45 | * and we'd like to still refer to them via C struct offsets. |
46 | * |
47 | * |
48 | * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group |
49 | * Portions Copyright (c) 1994, Regents of the University of California |
50 | * |
51 | * |
52 | * IDENTIFICATION |
53 | * src/backend/access/common/heaptuple.c |
54 | * |
55 | *------------------------------------------------------------------------- |
56 | */ |
57 | |
58 | #include "postgres.h" |
59 | |
60 | #include "access/sysattr.h" |
61 | #include "access/tupdesc_details.h" |
62 | #include "access/tuptoaster.h" |
63 | #include "executor/tuptable.h" |
64 | #include "utils/expandeddatum.h" |
65 | |
66 | |
67 | /* Does att's datatype allow packing into the 1-byte-header varlena format? */ |
68 | #define ATT_IS_PACKABLE(att) \ |
69 | ((att)->attlen == -1 && (att)->attstorage != 'p') |
70 | /* Use this if it's already known varlena */ |
71 | #define VARLENA_ATT_IS_PACKABLE(att) \ |
72 | ((att)->attstorage != 'p') |
73 | |
74 | |
75 | /* ---------------------------------------------------------------- |
76 | * misc support routines |
77 | * ---------------------------------------------------------------- |
78 | */ |
79 | |
80 | /* |
81 | * Return the missing value of an attribute, or NULL if there isn't one. |
82 | */ |
83 | Datum |
84 | getmissingattr(TupleDesc tupleDesc, |
85 | int attnum, bool *isnull) |
86 | { |
87 | Form_pg_attribute att; |
88 | |
89 | Assert(attnum <= tupleDesc->natts); |
90 | Assert(attnum > 0); |
91 | |
92 | att = TupleDescAttr(tupleDesc, attnum - 1); |
93 | |
94 | if (att->atthasmissing) |
95 | { |
96 | AttrMissing *attrmiss; |
97 | |
98 | Assert(tupleDesc->constr); |
99 | Assert(tupleDesc->constr->missing); |
100 | |
101 | attrmiss = tupleDesc->constr->missing + (attnum - 1); |
102 | |
103 | if (attrmiss->am_present) |
104 | { |
105 | *isnull = false; |
106 | return attrmiss->am_value; |
107 | } |
108 | } |
109 | |
110 | *isnull = true; |
111 | return PointerGetDatum(NULL); |
112 | } |
113 | |
114 | /* |
115 | * heap_compute_data_size |
116 | * Determine size of the data area of a tuple to be constructed |
117 | */ |
118 | Size |
119 | heap_compute_data_size(TupleDesc tupleDesc, |
120 | Datum *values, |
121 | bool *isnull) |
122 | { |
123 | Size data_length = 0; |
124 | int i; |
125 | int numberOfAttributes = tupleDesc->natts; |
126 | |
127 | for (i = 0; i < numberOfAttributes; i++) |
128 | { |
129 | Datum val; |
130 | Form_pg_attribute atti; |
131 | |
132 | if (isnull[i]) |
133 | continue; |
134 | |
135 | val = values[i]; |
136 | atti = TupleDescAttr(tupleDesc, i); |
137 | |
138 | if (ATT_IS_PACKABLE(atti) && |
139 | VARATT_CAN_MAKE_SHORT(DatumGetPointer(val))) |
140 | { |
141 | /* |
142 | * we're anticipating converting to a short varlena header, so |
143 | * adjust length and don't count any alignment |
144 | */ |
145 | data_length += VARATT_CONVERTED_SHORT_SIZE(DatumGetPointer(val)); |
146 | } |
147 | else if (atti->attlen == -1 && |
148 | VARATT_IS_EXTERNAL_EXPANDED(DatumGetPointer(val))) |
149 | { |
150 | /* |
151 | * we want to flatten the expanded value so that the constructed |
152 | * tuple doesn't depend on it |
153 | */ |
154 | data_length = att_align_nominal(data_length, atti->attalign); |
155 | data_length += EOH_get_flat_size(DatumGetEOHP(val)); |
156 | } |
157 | else |
158 | { |
159 | data_length = att_align_datum(data_length, atti->attalign, |
160 | atti->attlen, val); |
161 | data_length = att_addlength_datum(data_length, atti->attlen, |
162 | val); |
163 | } |
164 | } |
165 | |
166 | return data_length; |
167 | } |
168 | |
169 | /* |
170 | * Per-attribute helper for heap_fill_tuple and other routines building tuples. |
171 | * |
172 | * Fill in either a data value or a bit in the null bitmask |
173 | */ |
174 | static inline void |
175 | fill_val(Form_pg_attribute att, |
176 | bits8 **bit, |
177 | int *bitmask, |
178 | char **dataP, |
179 | uint16 *infomask, |
180 | Datum datum, |
181 | bool isnull) |
182 | { |
183 | Size data_length; |
184 | char *data = *dataP; |
185 | |
186 | /* |
187 | * If we're building a null bitmap, set the appropriate bit for the |
188 | * current column value here. |
189 | */ |
190 | if (bit != NULL) |
191 | { |
192 | if (*bitmask != HIGHBIT) |
193 | *bitmask <<= 1; |
194 | else |
195 | { |
196 | *bit += 1; |
197 | **bit = 0x0; |
198 | *bitmask = 1; |
199 | } |
200 | |
201 | if (isnull) |
202 | { |
203 | *infomask |= HEAP_HASNULL; |
204 | return; |
205 | } |
206 | |
207 | **bit |= *bitmask; |
208 | } |
209 | |
210 | /* |
211 | * XXX we use the att_align macros on the pointer value itself, not on an |
212 | * offset. This is a bit of a hack. |
213 | */ |
214 | if (att->attbyval) |
215 | { |
216 | /* pass-by-value */ |
217 | data = (char *) att_align_nominal(data, att->attalign); |
218 | store_att_byval(data, datum, att->attlen); |
219 | data_length = att->attlen; |
220 | } |
221 | else if (att->attlen == -1) |
222 | { |
223 | /* varlena */ |
224 | Pointer val = DatumGetPointer(datum); |
225 | |
226 | *infomask |= HEAP_HASVARWIDTH; |
227 | if (VARATT_IS_EXTERNAL(val)) |
228 | { |
229 | if (VARATT_IS_EXTERNAL_EXPANDED(val)) |
230 | { |
231 | /* |
232 | * we want to flatten the expanded value so that the |
233 | * constructed tuple doesn't depend on it |
234 | */ |
235 | ExpandedObjectHeader *eoh = DatumGetEOHP(datum); |
236 | |
237 | data = (char *) att_align_nominal(data, |
238 | att->attalign); |
239 | data_length = EOH_get_flat_size(eoh); |
240 | EOH_flatten_into(eoh, data, data_length); |
241 | } |
242 | else |
243 | { |
244 | *infomask |= HEAP_HASEXTERNAL; |
245 | /* no alignment, since it's short by definition */ |
246 | data_length = VARSIZE_EXTERNAL(val); |
247 | memcpy(data, val, data_length); |
248 | } |
249 | } |
250 | else if (VARATT_IS_SHORT(val)) |
251 | { |
252 | /* no alignment for short varlenas */ |
253 | data_length = VARSIZE_SHORT(val); |
254 | memcpy(data, val, data_length); |
255 | } |
256 | else if (VARLENA_ATT_IS_PACKABLE(att) && |
257 | VARATT_CAN_MAKE_SHORT(val)) |
258 | { |
259 | /* convert to short varlena -- no alignment */ |
260 | data_length = VARATT_CONVERTED_SHORT_SIZE(val); |
261 | SET_VARSIZE_SHORT(data, data_length); |
262 | memcpy(data + 1, VARDATA(val), data_length - 1); |
263 | } |
264 | else |
265 | { |
266 | /* full 4-byte header varlena */ |
267 | data = (char *) att_align_nominal(data, |
268 | att->attalign); |
269 | data_length = VARSIZE(val); |
270 | memcpy(data, val, data_length); |
271 | } |
272 | } |
273 | else if (att->attlen == -2) |
274 | { |
275 | /* cstring ... never needs alignment */ |
276 | *infomask |= HEAP_HASVARWIDTH; |
277 | Assert(att->attalign == 'c'); |
278 | data_length = strlen(DatumGetCString(datum)) + 1; |
279 | memcpy(data, DatumGetPointer(datum), data_length); |
280 | } |
281 | else |
282 | { |
283 | /* fixed-length pass-by-reference */ |
284 | data = (char *) att_align_nominal(data, att->attalign); |
285 | Assert(att->attlen > 0); |
286 | data_length = att->attlen; |
287 | memcpy(data, DatumGetPointer(datum), data_length); |
288 | } |
289 | |
290 | data += data_length; |
291 | *dataP = data; |
292 | } |
293 | |
294 | /* |
295 | * heap_fill_tuple |
296 | * Load data portion of a tuple from values/isnull arrays |
297 | * |
298 | * We also fill the null bitmap (if any) and set the infomask bits |
299 | * that reflect the tuple's data contents. |
300 | * |
301 | * NOTE: it is now REQUIRED that the caller have pre-zeroed the data area. |
302 | */ |
303 | void |
304 | heap_fill_tuple(TupleDesc tupleDesc, |
305 | Datum *values, bool *isnull, |
306 | char *data, Size data_size, |
307 | uint16 *infomask, bits8 *bit) |
308 | { |
309 | bits8 *bitP; |
310 | int bitmask; |
311 | int i; |
312 | int numberOfAttributes = tupleDesc->natts; |
313 | |
314 | #ifdef USE_ASSERT_CHECKING |
315 | char *start = data; |
316 | #endif |
317 | |
318 | if (bit != NULL) |
319 | { |
320 | bitP = &bit[-1]; |
321 | bitmask = HIGHBIT; |
322 | } |
323 | else |
324 | { |
325 | /* just to keep compiler quiet */ |
326 | bitP = NULL; |
327 | bitmask = 0; |
328 | } |
329 | |
330 | *infomask &= ~(HEAP_HASNULL | HEAP_HASVARWIDTH | HEAP_HASEXTERNAL); |
331 | |
332 | for (i = 0; i < numberOfAttributes; i++) |
333 | { |
334 | Form_pg_attribute attr = TupleDescAttr(tupleDesc, i); |
335 | |
336 | fill_val(attr, |
337 | bitP ? &bitP : NULL, |
338 | &bitmask, |
339 | &data, |
340 | infomask, |
341 | values ? values[i] : PointerGetDatum(NULL), |
342 | isnull ? isnull[i] : true); |
343 | } |
344 | |
345 | Assert((data - start) == data_size); |
346 | } |
347 | |
348 | |
349 | /* ---------------------------------------------------------------- |
350 | * heap tuple interface |
351 | * ---------------------------------------------------------------- |
352 | */ |
353 | |
354 | /* ---------------- |
355 | * heap_attisnull - returns true iff tuple attribute is not present |
356 | * ---------------- |
357 | */ |
358 | bool |
359 | heap_attisnull(HeapTuple tup, int attnum, TupleDesc tupleDesc) |
360 | { |
361 | /* |
362 | * We allow a NULL tupledesc for relations not expected to have missing |
363 | * values, such as catalog relations and indexes. |
364 | */ |
365 | Assert(!tupleDesc || attnum <= tupleDesc->natts); |
366 | if (attnum > (int) HeapTupleHeaderGetNatts(tup->t_data)) |
367 | { |
368 | if (tupleDesc && TupleDescAttr(tupleDesc, attnum - 1)->atthasmissing) |
369 | return false; |
370 | else |
371 | return true; |
372 | } |
373 | |
374 | if (attnum > 0) |
375 | { |
376 | if (HeapTupleNoNulls(tup)) |
377 | return false; |
378 | return att_isnull(attnum - 1, tup->t_data->t_bits); |
379 | } |
380 | |
381 | switch (attnum) |
382 | { |
383 | case TableOidAttributeNumber: |
384 | case SelfItemPointerAttributeNumber: |
385 | case MinTransactionIdAttributeNumber: |
386 | case MinCommandIdAttributeNumber: |
387 | case MaxTransactionIdAttributeNumber: |
388 | case MaxCommandIdAttributeNumber: |
389 | /* these are never null */ |
390 | break; |
391 | |
392 | default: |
393 | elog(ERROR, "invalid attnum: %d" , attnum); |
394 | } |
395 | |
396 | return false; |
397 | } |
398 | |
399 | /* ---------------- |
400 | * nocachegetattr |
401 | * |
402 | * This only gets called from fastgetattr() macro, in cases where |
403 | * we can't use a cacheoffset and the value is not null. |
404 | * |
405 | * This caches attribute offsets in the attribute descriptor. |
406 | * |
407 | * An alternative way to speed things up would be to cache offsets |
408 | * with the tuple, but that seems more difficult unless you take |
409 | * the storage hit of actually putting those offsets into the |
410 | * tuple you send to disk. Yuck. |
411 | * |
412 | * This scheme will be slightly slower than that, but should |
413 | * perform well for queries which hit large #'s of tuples. After |
414 | * you cache the offsets once, examining all the other tuples using |
415 | * the same attribute descriptor will go much quicker. -cim 5/4/91 |
416 | * |
417 | * NOTE: if you need to change this code, see also heap_deform_tuple. |
418 | * Also see nocache_index_getattr, which is the same code for index |
419 | * tuples. |
420 | * ---------------- |
421 | */ |
422 | Datum |
423 | nocachegetattr(HeapTuple tuple, |
424 | int attnum, |
425 | TupleDesc tupleDesc) |
426 | { |
427 | HeapTupleHeader tup = tuple->t_data; |
428 | char *tp; /* ptr to data part of tuple */ |
429 | bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */ |
430 | bool slow = false; /* do we have to walk attrs? */ |
431 | int off; /* current offset within data */ |
432 | |
433 | /* ---------------- |
434 | * Three cases: |
435 | * |
436 | * 1: No nulls and no variable-width attributes. |
437 | * 2: Has a null or a var-width AFTER att. |
438 | * 3: Has nulls or var-widths BEFORE att. |
439 | * ---------------- |
440 | */ |
441 | |
442 | attnum--; |
443 | |
444 | if (!HeapTupleNoNulls(tuple)) |
445 | { |
446 | /* |
447 | * there's a null somewhere in the tuple |
448 | * |
449 | * check to see if any preceding bits are null... |
450 | */ |
451 | int byte = attnum >> 3; |
452 | int finalbit = attnum & 0x07; |
453 | |
454 | /* check for nulls "before" final bit of last byte */ |
455 | if ((~bp[byte]) & ((1 << finalbit) - 1)) |
456 | slow = true; |
457 | else |
458 | { |
459 | /* check for nulls in any "earlier" bytes */ |
460 | int i; |
461 | |
462 | for (i = 0; i < byte; i++) |
463 | { |
464 | if (bp[i] != 0xFF) |
465 | { |
466 | slow = true; |
467 | break; |
468 | } |
469 | } |
470 | } |
471 | } |
472 | |
473 | tp = (char *) tup + tup->t_hoff; |
474 | |
475 | if (!slow) |
476 | { |
477 | Form_pg_attribute att; |
478 | |
479 | /* |
480 | * If we get here, there are no nulls up to and including the target |
481 | * attribute. If we have a cached offset, we can use it. |
482 | */ |
483 | att = TupleDescAttr(tupleDesc, attnum); |
484 | if (att->attcacheoff >= 0) |
485 | return fetchatt(att, tp + att->attcacheoff); |
486 | |
487 | /* |
488 | * Otherwise, check for non-fixed-length attrs up to and including |
489 | * target. If there aren't any, it's safe to cheaply initialize the |
490 | * cached offsets for these attrs. |
491 | */ |
492 | if (HeapTupleHasVarWidth(tuple)) |
493 | { |
494 | int j; |
495 | |
496 | for (j = 0; j <= attnum; j++) |
497 | { |
498 | if (TupleDescAttr(tupleDesc, j)->attlen <= 0) |
499 | { |
500 | slow = true; |
501 | break; |
502 | } |
503 | } |
504 | } |
505 | } |
506 | |
507 | if (!slow) |
508 | { |
509 | int natts = tupleDesc->natts; |
510 | int j = 1; |
511 | |
512 | /* |
513 | * If we get here, we have a tuple with no nulls or var-widths up to |
514 | * and including the target attribute, so we can use the cached offset |
515 | * ... only we don't have it yet, or we'd not have got here. Since |
516 | * it's cheap to compute offsets for fixed-width columns, we take the |
517 | * opportunity to initialize the cached offsets for *all* the leading |
518 | * fixed-width columns, in hope of avoiding future visits to this |
519 | * routine. |
520 | */ |
521 | TupleDescAttr(tupleDesc, 0)->attcacheoff = 0; |
522 | |
523 | /* we might have set some offsets in the slow path previously */ |
524 | while (j < natts && TupleDescAttr(tupleDesc, j)->attcacheoff > 0) |
525 | j++; |
526 | |
527 | off = TupleDescAttr(tupleDesc, j - 1)->attcacheoff + |
528 | TupleDescAttr(tupleDesc, j - 1)->attlen; |
529 | |
530 | for (; j < natts; j++) |
531 | { |
532 | Form_pg_attribute att = TupleDescAttr(tupleDesc, j); |
533 | |
534 | if (att->attlen <= 0) |
535 | break; |
536 | |
537 | off = att_align_nominal(off, att->attalign); |
538 | |
539 | att->attcacheoff = off; |
540 | |
541 | off += att->attlen; |
542 | } |
543 | |
544 | Assert(j > attnum); |
545 | |
546 | off = TupleDescAttr(tupleDesc, attnum)->attcacheoff; |
547 | } |
548 | else |
549 | { |
550 | bool usecache = true; |
551 | int i; |
552 | |
553 | /* |
554 | * Now we know that we have to walk the tuple CAREFULLY. But we still |
555 | * might be able to cache some offsets for next time. |
556 | * |
557 | * Note - This loop is a little tricky. For each non-null attribute, |
558 | * we have to first account for alignment padding before the attr, |
559 | * then advance over the attr based on its length. Nulls have no |
560 | * storage and no alignment padding either. We can use/set |
561 | * attcacheoff until we reach either a null or a var-width attribute. |
562 | */ |
563 | off = 0; |
564 | for (i = 0;; i++) /* loop exit is at "break" */ |
565 | { |
566 | Form_pg_attribute att = TupleDescAttr(tupleDesc, i); |
567 | |
568 | if (HeapTupleHasNulls(tuple) && att_isnull(i, bp)) |
569 | { |
570 | usecache = false; |
571 | continue; /* this cannot be the target att */ |
572 | } |
573 | |
574 | /* If we know the next offset, we can skip the rest */ |
575 | if (usecache && att->attcacheoff >= 0) |
576 | off = att->attcacheoff; |
577 | else if (att->attlen == -1) |
578 | { |
579 | /* |
580 | * We can only cache the offset for a varlena attribute if the |
581 | * offset is already suitably aligned, so that there would be |
582 | * no pad bytes in any case: then the offset will be valid for |
583 | * either an aligned or unaligned value. |
584 | */ |
585 | if (usecache && |
586 | off == att_align_nominal(off, att->attalign)) |
587 | att->attcacheoff = off; |
588 | else |
589 | { |
590 | off = att_align_pointer(off, att->attalign, -1, |
591 | tp + off); |
592 | usecache = false; |
593 | } |
594 | } |
595 | else |
596 | { |
597 | /* not varlena, so safe to use att_align_nominal */ |
598 | off = att_align_nominal(off, att->attalign); |
599 | |
600 | if (usecache) |
601 | att->attcacheoff = off; |
602 | } |
603 | |
604 | if (i == attnum) |
605 | break; |
606 | |
607 | off = att_addlength_pointer(off, att->attlen, tp + off); |
608 | |
609 | if (usecache && att->attlen <= 0) |
610 | usecache = false; |
611 | } |
612 | } |
613 | |
614 | return fetchatt(TupleDescAttr(tupleDesc, attnum), tp + off); |
615 | } |
616 | |
617 | /* ---------------- |
618 | * heap_getsysattr |
619 | * |
620 | * Fetch the value of a system attribute for a tuple. |
621 | * |
622 | * This is a support routine for the heap_getattr macro. The macro |
623 | * has already determined that the attnum refers to a system attribute. |
624 | * ---------------- |
625 | */ |
626 | Datum |
627 | heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull) |
628 | { |
629 | Datum result; |
630 | |
631 | Assert(tup); |
632 | |
633 | /* Currently, no sys attribute ever reads as NULL. */ |
634 | *isnull = false; |
635 | |
636 | switch (attnum) |
637 | { |
638 | case SelfItemPointerAttributeNumber: |
639 | /* pass-by-reference datatype */ |
640 | result = PointerGetDatum(&(tup->t_self)); |
641 | break; |
642 | case MinTransactionIdAttributeNumber: |
643 | result = TransactionIdGetDatum(HeapTupleHeaderGetRawXmin(tup->t_data)); |
644 | break; |
645 | case MaxTransactionIdAttributeNumber: |
646 | result = TransactionIdGetDatum(HeapTupleHeaderGetRawXmax(tup->t_data)); |
647 | break; |
648 | case MinCommandIdAttributeNumber: |
649 | case MaxCommandIdAttributeNumber: |
650 | |
651 | /* |
652 | * cmin and cmax are now both aliases for the same field, which |
653 | * can in fact also be a combo command id. XXX perhaps we should |
654 | * return the "real" cmin or cmax if possible, that is if we are |
655 | * inside the originating transaction? |
656 | */ |
657 | result = CommandIdGetDatum(HeapTupleHeaderGetRawCommandId(tup->t_data)); |
658 | break; |
659 | case TableOidAttributeNumber: |
660 | result = ObjectIdGetDatum(tup->t_tableOid); |
661 | break; |
662 | default: |
663 | elog(ERROR, "invalid attnum: %d" , attnum); |
664 | result = 0; /* keep compiler quiet */ |
665 | break; |
666 | } |
667 | return result; |
668 | } |
669 | |
670 | /* ---------------- |
671 | * heap_copytuple |
672 | * |
673 | * returns a copy of an entire tuple |
674 | * |
675 | * The HeapTuple struct, tuple header, and tuple data are all allocated |
676 | * as a single palloc() block. |
677 | * ---------------- |
678 | */ |
679 | HeapTuple |
680 | heap_copytuple(HeapTuple tuple) |
681 | { |
682 | HeapTuple newTuple; |
683 | |
684 | if (!HeapTupleIsValid(tuple) || tuple->t_data == NULL) |
685 | return NULL; |
686 | |
687 | newTuple = (HeapTuple) palloc(HEAPTUPLESIZE + tuple->t_len); |
688 | newTuple->t_len = tuple->t_len; |
689 | newTuple->t_self = tuple->t_self; |
690 | newTuple->t_tableOid = tuple->t_tableOid; |
691 | newTuple->t_data = (HeapTupleHeader) ((char *) newTuple + HEAPTUPLESIZE); |
692 | memcpy((char *) newTuple->t_data, (char *) tuple->t_data, tuple->t_len); |
693 | return newTuple; |
694 | } |
695 | |
696 | /* ---------------- |
697 | * heap_copytuple_with_tuple |
698 | * |
699 | * copy a tuple into a caller-supplied HeapTuple management struct |
700 | * |
701 | * Note that after calling this function, the "dest" HeapTuple will not be |
702 | * allocated as a single palloc() block (unlike with heap_copytuple()). |
703 | * ---------------- |
704 | */ |
705 | void |
706 | heap_copytuple_with_tuple(HeapTuple src, HeapTuple dest) |
707 | { |
708 | if (!HeapTupleIsValid(src) || src->t_data == NULL) |
709 | { |
710 | dest->t_data = NULL; |
711 | return; |
712 | } |
713 | |
714 | dest->t_len = src->t_len; |
715 | dest->t_self = src->t_self; |
716 | dest->t_tableOid = src->t_tableOid; |
717 | dest->t_data = (HeapTupleHeader) palloc(src->t_len); |
718 | memcpy((char *) dest->t_data, (char *) src->t_data, src->t_len); |
719 | } |
720 | |
721 | /* |
722 | * Expand a tuple which has less attributes than required. For each attribute |
723 | * not present in the sourceTuple, if there is a missing value that will be |
724 | * used. Otherwise the attribute will be set to NULL. |
725 | * |
726 | * The source tuple must have less attributes than the required number. |
727 | * |
728 | * Only one of targetHeapTuple and targetMinimalTuple may be supplied. The |
729 | * other argument must be NULL. |
730 | */ |
731 | static void |
732 | expand_tuple(HeapTuple *targetHeapTuple, |
733 | MinimalTuple *targetMinimalTuple, |
734 | HeapTuple sourceTuple, |
735 | TupleDesc tupleDesc) |
736 | { |
737 | AttrMissing *attrmiss = NULL; |
738 | int attnum; |
739 | int firstmissingnum = 0; |
740 | bool hasNulls = HeapTupleHasNulls(sourceTuple); |
741 | HeapTupleHeader ; |
742 | HeapTupleHeader = sourceTuple->t_data; |
743 | int sourceNatts = HeapTupleHeaderGetNatts(sourceTHeader); |
744 | int natts = tupleDesc->natts; |
745 | int sourceNullLen; |
746 | int targetNullLen; |
747 | Size sourceDataLen = sourceTuple->t_len - sourceTHeader->t_hoff; |
748 | Size targetDataLen; |
749 | Size len; |
750 | int hoff; |
751 | bits8 *nullBits = NULL; |
752 | int bitMask = 0; |
753 | char *targetData; |
754 | uint16 *infoMask; |
755 | |
756 | Assert((targetHeapTuple && !targetMinimalTuple) |
757 | || (!targetHeapTuple && targetMinimalTuple)); |
758 | |
759 | Assert(sourceNatts < natts); |
760 | |
761 | sourceNullLen = (hasNulls ? BITMAPLEN(sourceNatts) : 0); |
762 | |
763 | targetDataLen = sourceDataLen; |
764 | |
765 | if (tupleDesc->constr && |
766 | tupleDesc->constr->missing) |
767 | { |
768 | /* |
769 | * If there are missing values we want to put them into the tuple. |
770 | * Before that we have to compute the extra length for the values |
771 | * array and the variable length data. |
772 | */ |
773 | attrmiss = tupleDesc->constr->missing; |
774 | |
775 | /* |
776 | * Find the first item in attrmiss for which we don't have a value in |
777 | * the source. We can ignore all the missing entries before that. |
778 | */ |
779 | for (firstmissingnum = sourceNatts; |
780 | firstmissingnum < natts; |
781 | firstmissingnum++) |
782 | { |
783 | if (attrmiss[firstmissingnum].am_present) |
784 | break; |
785 | else |
786 | hasNulls = true; |
787 | } |
788 | |
789 | /* |
790 | * Now walk the missing attributes. If there is a missing value make |
791 | * space for it. Otherwise, it's going to be NULL. |
792 | */ |
793 | for (attnum = firstmissingnum; |
794 | attnum < natts; |
795 | attnum++) |
796 | { |
797 | if (attrmiss[attnum].am_present) |
798 | { |
799 | Form_pg_attribute att = TupleDescAttr(tupleDesc, attnum); |
800 | |
801 | targetDataLen = att_align_datum(targetDataLen, |
802 | att->attalign, |
803 | att->attlen, |
804 | attrmiss[attnum].am_value); |
805 | |
806 | targetDataLen = att_addlength_pointer(targetDataLen, |
807 | att->attlen, |
808 | attrmiss[attnum].am_value); |
809 | } |
810 | else |
811 | { |
812 | /* no missing value, so it must be null */ |
813 | hasNulls = true; |
814 | } |
815 | } |
816 | } /* end if have missing values */ |
817 | else |
818 | { |
819 | /* |
820 | * If there are no missing values at all then NULLS must be allowed, |
821 | * since some of the attributes are known to be absent. |
822 | */ |
823 | hasNulls = true; |
824 | } |
825 | |
826 | len = 0; |
827 | |
828 | if (hasNulls) |
829 | { |
830 | targetNullLen = BITMAPLEN(natts); |
831 | len += targetNullLen; |
832 | } |
833 | else |
834 | targetNullLen = 0; |
835 | |
836 | /* |
837 | * Allocate and zero the space needed. Note that the tuple body and |
838 | * HeapTupleData management structure are allocated in one chunk. |
839 | */ |
840 | if (targetHeapTuple) |
841 | { |
842 | len += offsetof(HeapTupleHeaderData, t_bits); |
843 | hoff = len = MAXALIGN(len); /* align user data safely */ |
844 | len += targetDataLen; |
845 | |
846 | *targetHeapTuple = (HeapTuple) palloc0(HEAPTUPLESIZE + len); |
847 | (*targetHeapTuple)->t_data |
848 | = targetTHeader |
849 | = (HeapTupleHeader) ((char *) *targetHeapTuple + HEAPTUPLESIZE); |
850 | (*targetHeapTuple)->t_len = len; |
851 | (*targetHeapTuple)->t_tableOid = sourceTuple->t_tableOid; |
852 | (*targetHeapTuple)->t_self = sourceTuple->t_self; |
853 | |
854 | targetTHeader->t_infomask = sourceTHeader->t_infomask; |
855 | targetTHeader->t_hoff = hoff; |
856 | HeapTupleHeaderSetNatts(targetTHeader, natts); |
857 | HeapTupleHeaderSetDatumLength(targetTHeader, len); |
858 | HeapTupleHeaderSetTypeId(targetTHeader, tupleDesc->tdtypeid); |
859 | HeapTupleHeaderSetTypMod(targetTHeader, tupleDesc->tdtypmod); |
860 | /* We also make sure that t_ctid is invalid unless explicitly set */ |
861 | ItemPointerSetInvalid(&(targetTHeader->t_ctid)); |
862 | if (targetNullLen > 0) |
863 | nullBits = (bits8 *) ((char *) (*targetHeapTuple)->t_data |
864 | + offsetof(HeapTupleHeaderData, t_bits)); |
865 | targetData = (char *) (*targetHeapTuple)->t_data + hoff; |
866 | infoMask = &(targetTHeader->t_infomask); |
867 | } |
868 | else |
869 | { |
870 | len += SizeofMinimalTupleHeader; |
871 | hoff = len = MAXALIGN(len); /* align user data safely */ |
872 | len += targetDataLen; |
873 | |
874 | *targetMinimalTuple = (MinimalTuple) palloc0(len); |
875 | (*targetMinimalTuple)->t_len = len; |
876 | (*targetMinimalTuple)->t_hoff = hoff + MINIMAL_TUPLE_OFFSET; |
877 | (*targetMinimalTuple)->t_infomask = sourceTHeader->t_infomask; |
878 | /* Same macro works for MinimalTuples */ |
879 | HeapTupleHeaderSetNatts(*targetMinimalTuple, natts); |
880 | if (targetNullLen > 0) |
881 | nullBits = (bits8 *) ((char *) *targetMinimalTuple |
882 | + offsetof(MinimalTupleData, t_bits)); |
883 | targetData = (char *) *targetMinimalTuple + hoff; |
884 | infoMask = &((*targetMinimalTuple)->t_infomask); |
885 | } |
886 | |
887 | if (targetNullLen > 0) |
888 | { |
889 | if (sourceNullLen > 0) |
890 | { |
891 | /* if bitmap pre-existed copy in - all is set */ |
892 | memcpy(nullBits, |
893 | ((char *) sourceTHeader) |
894 | + offsetof(HeapTupleHeaderData, t_bits), |
895 | sourceNullLen); |
896 | nullBits += sourceNullLen - 1; |
897 | } |
898 | else |
899 | { |
900 | sourceNullLen = BITMAPLEN(sourceNatts); |
901 | /* Set NOT NULL for all existing attributes */ |
902 | memset(nullBits, 0xff, sourceNullLen); |
903 | |
904 | nullBits += sourceNullLen - 1; |
905 | |
906 | if (sourceNatts & 0x07) |
907 | { |
908 | /* build the mask (inverted!) */ |
909 | bitMask = 0xff << (sourceNatts & 0x07); |
910 | /* Voila */ |
911 | *nullBits = ~bitMask; |
912 | } |
913 | } |
914 | |
915 | bitMask = (1 << ((sourceNatts - 1) & 0x07)); |
916 | } /* End if have null bitmap */ |
917 | |
918 | memcpy(targetData, |
919 | ((char *) sourceTuple->t_data) + sourceTHeader->t_hoff, |
920 | sourceDataLen); |
921 | |
922 | targetData += sourceDataLen; |
923 | |
924 | /* Now fill in the missing values */ |
925 | for (attnum = sourceNatts; attnum < natts; attnum++) |
926 | { |
927 | |
928 | Form_pg_attribute attr = TupleDescAttr(tupleDesc, attnum); |
929 | |
930 | if (attrmiss && attrmiss[attnum].am_present) |
931 | { |
932 | fill_val(attr, |
933 | nullBits ? &nullBits : NULL, |
934 | &bitMask, |
935 | &targetData, |
936 | infoMask, |
937 | attrmiss[attnum].am_value, |
938 | false); |
939 | } |
940 | else |
941 | { |
942 | fill_val(attr, |
943 | &nullBits, |
944 | &bitMask, |
945 | &targetData, |
946 | infoMask, |
947 | (Datum) 0, |
948 | true); |
949 | } |
950 | } /* end loop over missing attributes */ |
951 | } |
952 | |
953 | /* |
954 | * Fill in the missing values for a minimal HeapTuple |
955 | */ |
956 | MinimalTuple |
957 | minimal_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc) |
958 | { |
959 | MinimalTuple minimalTuple; |
960 | |
961 | expand_tuple(NULL, &minimalTuple, sourceTuple, tupleDesc); |
962 | return minimalTuple; |
963 | } |
964 | |
965 | /* |
966 | * Fill in the missing values for an ordinary HeapTuple |
967 | */ |
968 | HeapTuple |
969 | heap_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc) |
970 | { |
971 | HeapTuple heapTuple; |
972 | |
973 | expand_tuple(&heapTuple, NULL, sourceTuple, tupleDesc); |
974 | return heapTuple; |
975 | } |
976 | |
977 | /* ---------------- |
978 | * heap_copy_tuple_as_datum |
979 | * |
980 | * copy a tuple as a composite-type Datum |
981 | * ---------------- |
982 | */ |
983 | Datum |
984 | heap_copy_tuple_as_datum(HeapTuple tuple, TupleDesc tupleDesc) |
985 | { |
986 | HeapTupleHeader td; |
987 | |
988 | /* |
989 | * If the tuple contains any external TOAST pointers, we have to inline |
990 | * those fields to meet the conventions for composite-type Datums. |
991 | */ |
992 | if (HeapTupleHasExternal(tuple)) |
993 | return toast_flatten_tuple_to_datum(tuple->t_data, |
994 | tuple->t_len, |
995 | tupleDesc); |
996 | |
997 | /* |
998 | * Fast path for easy case: just make a palloc'd copy and insert the |
999 | * correct composite-Datum header fields (since those may not be set if |
1000 | * the given tuple came from disk, rather than from heap_form_tuple). |
1001 | */ |
1002 | td = (HeapTupleHeader) palloc(tuple->t_len); |
1003 | memcpy((char *) td, (char *) tuple->t_data, tuple->t_len); |
1004 | |
1005 | HeapTupleHeaderSetDatumLength(td, tuple->t_len); |
1006 | HeapTupleHeaderSetTypeId(td, tupleDesc->tdtypeid); |
1007 | HeapTupleHeaderSetTypMod(td, tupleDesc->tdtypmod); |
1008 | |
1009 | return PointerGetDatum(td); |
1010 | } |
1011 | |
1012 | /* |
1013 | * heap_form_tuple |
1014 | * construct a tuple from the given values[] and isnull[] arrays, |
1015 | * which are of the length indicated by tupleDescriptor->natts |
1016 | * |
1017 | * The result is allocated in the current memory context. |
1018 | */ |
1019 | HeapTuple |
1020 | heap_form_tuple(TupleDesc tupleDescriptor, |
1021 | Datum *values, |
1022 | bool *isnull) |
1023 | { |
1024 | HeapTuple tuple; /* return tuple */ |
1025 | HeapTupleHeader td; /* tuple data */ |
1026 | Size len, |
1027 | data_len; |
1028 | int hoff; |
1029 | bool hasnull = false; |
1030 | int numberOfAttributes = tupleDescriptor->natts; |
1031 | int i; |
1032 | |
1033 | if (numberOfAttributes > MaxTupleAttributeNumber) |
1034 | ereport(ERROR, |
1035 | (errcode(ERRCODE_TOO_MANY_COLUMNS), |
1036 | errmsg("number of columns (%d) exceeds limit (%d)" , |
1037 | numberOfAttributes, MaxTupleAttributeNumber))); |
1038 | |
1039 | /* |
1040 | * Check for nulls |
1041 | */ |
1042 | for (i = 0; i < numberOfAttributes; i++) |
1043 | { |
1044 | if (isnull[i]) |
1045 | { |
1046 | hasnull = true; |
1047 | break; |
1048 | } |
1049 | } |
1050 | |
1051 | /* |
1052 | * Determine total space needed |
1053 | */ |
1054 | len = offsetof(HeapTupleHeaderData, t_bits); |
1055 | |
1056 | if (hasnull) |
1057 | len += BITMAPLEN(numberOfAttributes); |
1058 | |
1059 | hoff = len = MAXALIGN(len); /* align user data safely */ |
1060 | |
1061 | data_len = heap_compute_data_size(tupleDescriptor, values, isnull); |
1062 | |
1063 | len += data_len; |
1064 | |
1065 | /* |
1066 | * Allocate and zero the space needed. Note that the tuple body and |
1067 | * HeapTupleData management structure are allocated in one chunk. |
1068 | */ |
1069 | tuple = (HeapTuple) palloc0(HEAPTUPLESIZE + len); |
1070 | tuple->t_data = td = (HeapTupleHeader) ((char *) tuple + HEAPTUPLESIZE); |
1071 | |
1072 | /* |
1073 | * And fill in the information. Note we fill the Datum fields even though |
1074 | * this tuple may never become a Datum. This lets HeapTupleHeaderGetDatum |
1075 | * identify the tuple type if needed. |
1076 | */ |
1077 | tuple->t_len = len; |
1078 | ItemPointerSetInvalid(&(tuple->t_self)); |
1079 | tuple->t_tableOid = InvalidOid; |
1080 | |
1081 | HeapTupleHeaderSetDatumLength(td, len); |
1082 | HeapTupleHeaderSetTypeId(td, tupleDescriptor->tdtypeid); |
1083 | HeapTupleHeaderSetTypMod(td, tupleDescriptor->tdtypmod); |
1084 | /* We also make sure that t_ctid is invalid unless explicitly set */ |
1085 | ItemPointerSetInvalid(&(td->t_ctid)); |
1086 | |
1087 | HeapTupleHeaderSetNatts(td, numberOfAttributes); |
1088 | td->t_hoff = hoff; |
1089 | |
1090 | heap_fill_tuple(tupleDescriptor, |
1091 | values, |
1092 | isnull, |
1093 | (char *) td + hoff, |
1094 | data_len, |
1095 | &td->t_infomask, |
1096 | (hasnull ? td->t_bits : NULL)); |
1097 | |
1098 | return tuple; |
1099 | } |
1100 | |
1101 | /* |
1102 | * heap_modify_tuple |
1103 | * form a new tuple from an old tuple and a set of replacement values. |
1104 | * |
1105 | * The replValues, replIsnull, and doReplace arrays must be of the length |
1106 | * indicated by tupleDesc->natts. The new tuple is constructed using the data |
1107 | * from replValues/replIsnull at columns where doReplace is true, and using |
1108 | * the data from the old tuple at columns where doReplace is false. |
1109 | * |
1110 | * The result is allocated in the current memory context. |
1111 | */ |
1112 | HeapTuple |
1113 | heap_modify_tuple(HeapTuple tuple, |
1114 | TupleDesc tupleDesc, |
1115 | Datum *replValues, |
1116 | bool *replIsnull, |
1117 | bool *doReplace) |
1118 | { |
1119 | int numberOfAttributes = tupleDesc->natts; |
1120 | int attoff; |
1121 | Datum *values; |
1122 | bool *isnull; |
1123 | HeapTuple newTuple; |
1124 | |
1125 | /* |
1126 | * allocate and fill values and isnull arrays from either the tuple or the |
1127 | * repl information, as appropriate. |
1128 | * |
1129 | * NOTE: it's debatable whether to use heap_deform_tuple() here or just |
1130 | * heap_getattr() only the non-replaced columns. The latter could win if |
1131 | * there are many replaced columns and few non-replaced ones. However, |
1132 | * heap_deform_tuple costs only O(N) while the heap_getattr way would cost |
1133 | * O(N^2) if there are many non-replaced columns, so it seems better to |
1134 | * err on the side of linear cost. |
1135 | */ |
1136 | values = (Datum *) palloc(numberOfAttributes * sizeof(Datum)); |
1137 | isnull = (bool *) palloc(numberOfAttributes * sizeof(bool)); |
1138 | |
1139 | heap_deform_tuple(tuple, tupleDesc, values, isnull); |
1140 | |
1141 | for (attoff = 0; attoff < numberOfAttributes; attoff++) |
1142 | { |
1143 | if (doReplace[attoff]) |
1144 | { |
1145 | values[attoff] = replValues[attoff]; |
1146 | isnull[attoff] = replIsnull[attoff]; |
1147 | } |
1148 | } |
1149 | |
1150 | /* |
1151 | * create a new tuple from the values and isnull arrays |
1152 | */ |
1153 | newTuple = heap_form_tuple(tupleDesc, values, isnull); |
1154 | |
1155 | pfree(values); |
1156 | pfree(isnull); |
1157 | |
1158 | /* |
1159 | * copy the identification info of the old tuple: t_ctid, t_self |
1160 | */ |
1161 | newTuple->t_data->t_ctid = tuple->t_data->t_ctid; |
1162 | newTuple->t_self = tuple->t_self; |
1163 | newTuple->t_tableOid = tuple->t_tableOid; |
1164 | |
1165 | return newTuple; |
1166 | } |
1167 | |
1168 | /* |
1169 | * heap_modify_tuple_by_cols |
1170 | * form a new tuple from an old tuple and a set of replacement values. |
1171 | * |
1172 | * This is like heap_modify_tuple, except that instead of specifying which |
1173 | * column(s) to replace by a boolean map, an array of target column numbers |
1174 | * is used. This is often more convenient when a fixed number of columns |
1175 | * are to be replaced. The replCols, replValues, and replIsnull arrays must |
1176 | * be of length nCols. Target column numbers are indexed from 1. |
1177 | * |
1178 | * The result is allocated in the current memory context. |
1179 | */ |
1180 | HeapTuple |
1181 | heap_modify_tuple_by_cols(HeapTuple tuple, |
1182 | TupleDesc tupleDesc, |
1183 | int nCols, |
1184 | int *replCols, |
1185 | Datum *replValues, |
1186 | bool *replIsnull) |
1187 | { |
1188 | int numberOfAttributes = tupleDesc->natts; |
1189 | Datum *values; |
1190 | bool *isnull; |
1191 | HeapTuple newTuple; |
1192 | int i; |
1193 | |
1194 | /* |
1195 | * allocate and fill values and isnull arrays from the tuple, then replace |
1196 | * selected columns from the input arrays. |
1197 | */ |
1198 | values = (Datum *) palloc(numberOfAttributes * sizeof(Datum)); |
1199 | isnull = (bool *) palloc(numberOfAttributes * sizeof(bool)); |
1200 | |
1201 | heap_deform_tuple(tuple, tupleDesc, values, isnull); |
1202 | |
1203 | for (i = 0; i < nCols; i++) |
1204 | { |
1205 | int attnum = replCols[i]; |
1206 | |
1207 | if (attnum <= 0 || attnum > numberOfAttributes) |
1208 | elog(ERROR, "invalid column number %d" , attnum); |
1209 | values[attnum - 1] = replValues[i]; |
1210 | isnull[attnum - 1] = replIsnull[i]; |
1211 | } |
1212 | |
1213 | /* |
1214 | * create a new tuple from the values and isnull arrays |
1215 | */ |
1216 | newTuple = heap_form_tuple(tupleDesc, values, isnull); |
1217 | |
1218 | pfree(values); |
1219 | pfree(isnull); |
1220 | |
1221 | /* |
1222 | * copy the identification info of the old tuple: t_ctid, t_self |
1223 | */ |
1224 | newTuple->t_data->t_ctid = tuple->t_data->t_ctid; |
1225 | newTuple->t_self = tuple->t_self; |
1226 | newTuple->t_tableOid = tuple->t_tableOid; |
1227 | |
1228 | return newTuple; |
1229 | } |
1230 | |
1231 | /* |
1232 | * heap_deform_tuple |
1233 | * Given a tuple, extract data into values/isnull arrays; this is |
1234 | * the inverse of heap_form_tuple. |
1235 | * |
1236 | * Storage for the values/isnull arrays is provided by the caller; |
1237 | * it should be sized according to tupleDesc->natts not |
1238 | * HeapTupleHeaderGetNatts(tuple->t_data). |
1239 | * |
1240 | * Note that for pass-by-reference datatypes, the pointer placed |
1241 | * in the Datum will point into the given tuple. |
1242 | * |
1243 | * When all or most of a tuple's fields need to be extracted, |
1244 | * this routine will be significantly quicker than a loop around |
1245 | * heap_getattr; the loop will become O(N^2) as soon as any |
1246 | * noncacheable attribute offsets are involved. |
1247 | */ |
1248 | void |
1249 | heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc, |
1250 | Datum *values, bool *isnull) |
1251 | { |
1252 | HeapTupleHeader tup = tuple->t_data; |
1253 | bool hasnulls = HeapTupleHasNulls(tuple); |
1254 | int tdesc_natts = tupleDesc->natts; |
1255 | int natts; /* number of atts to extract */ |
1256 | int attnum; |
1257 | char *tp; /* ptr to tuple data */ |
1258 | uint32 off; /* offset in tuple data */ |
1259 | bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */ |
1260 | bool slow = false; /* can we use/set attcacheoff? */ |
1261 | |
1262 | natts = HeapTupleHeaderGetNatts(tup); |
1263 | |
1264 | /* |
1265 | * In inheritance situations, it is possible that the given tuple actually |
1266 | * has more fields than the caller is expecting. Don't run off the end of |
1267 | * the caller's arrays. |
1268 | */ |
1269 | natts = Min(natts, tdesc_natts); |
1270 | |
1271 | tp = (char *) tup + tup->t_hoff; |
1272 | |
1273 | off = 0; |
1274 | |
1275 | for (attnum = 0; attnum < natts; attnum++) |
1276 | { |
1277 | Form_pg_attribute thisatt = TupleDescAttr(tupleDesc, attnum); |
1278 | |
1279 | if (hasnulls && att_isnull(attnum, bp)) |
1280 | { |
1281 | values[attnum] = (Datum) 0; |
1282 | isnull[attnum] = true; |
1283 | slow = true; /* can't use attcacheoff anymore */ |
1284 | continue; |
1285 | } |
1286 | |
1287 | isnull[attnum] = false; |
1288 | |
1289 | if (!slow && thisatt->attcacheoff >= 0) |
1290 | off = thisatt->attcacheoff; |
1291 | else if (thisatt->attlen == -1) |
1292 | { |
1293 | /* |
1294 | * We can only cache the offset for a varlena attribute if the |
1295 | * offset is already suitably aligned, so that there would be no |
1296 | * pad bytes in any case: then the offset will be valid for either |
1297 | * an aligned or unaligned value. |
1298 | */ |
1299 | if (!slow && |
1300 | off == att_align_nominal(off, thisatt->attalign)) |
1301 | thisatt->attcacheoff = off; |
1302 | else |
1303 | { |
1304 | off = att_align_pointer(off, thisatt->attalign, -1, |
1305 | tp + off); |
1306 | slow = true; |
1307 | } |
1308 | } |
1309 | else |
1310 | { |
1311 | /* not varlena, so safe to use att_align_nominal */ |
1312 | off = att_align_nominal(off, thisatt->attalign); |
1313 | |
1314 | if (!slow) |
1315 | thisatt->attcacheoff = off; |
1316 | } |
1317 | |
1318 | values[attnum] = fetchatt(thisatt, tp + off); |
1319 | |
1320 | off = att_addlength_pointer(off, thisatt->attlen, tp + off); |
1321 | |
1322 | if (thisatt->attlen <= 0) |
1323 | slow = true; /* can't use attcacheoff anymore */ |
1324 | } |
1325 | |
1326 | /* |
1327 | * If tuple doesn't have all the atts indicated by tupleDesc, read the |
1328 | * rest as nulls or missing values as appropriate. |
1329 | */ |
1330 | for (; attnum < tdesc_natts; attnum++) |
1331 | values[attnum] = getmissingattr(tupleDesc, attnum + 1, &isnull[attnum]); |
1332 | } |
1333 | |
1334 | /* |
1335 | * heap_freetuple |
1336 | */ |
1337 | void |
1338 | heap_freetuple(HeapTuple htup) |
1339 | { |
1340 | pfree(htup); |
1341 | } |
1342 | |
1343 | |
1344 | /* |
1345 | * heap_form_minimal_tuple |
1346 | * construct a MinimalTuple from the given values[] and isnull[] arrays, |
1347 | * which are of the length indicated by tupleDescriptor->natts |
1348 | * |
1349 | * This is exactly like heap_form_tuple() except that the result is a |
1350 | * "minimal" tuple lacking a HeapTupleData header as well as room for system |
1351 | * columns. |
1352 | * |
1353 | * The result is allocated in the current memory context. |
1354 | */ |
1355 | MinimalTuple |
1356 | heap_form_minimal_tuple(TupleDesc tupleDescriptor, |
1357 | Datum *values, |
1358 | bool *isnull) |
1359 | { |
1360 | MinimalTuple tuple; /* return tuple */ |
1361 | Size len, |
1362 | data_len; |
1363 | int hoff; |
1364 | bool hasnull = false; |
1365 | int numberOfAttributes = tupleDescriptor->natts; |
1366 | int i; |
1367 | |
1368 | if (numberOfAttributes > MaxTupleAttributeNumber) |
1369 | ereport(ERROR, |
1370 | (errcode(ERRCODE_TOO_MANY_COLUMNS), |
1371 | errmsg("number of columns (%d) exceeds limit (%d)" , |
1372 | numberOfAttributes, MaxTupleAttributeNumber))); |
1373 | |
1374 | /* |
1375 | * Check for nulls |
1376 | */ |
1377 | for (i = 0; i < numberOfAttributes; i++) |
1378 | { |
1379 | if (isnull[i]) |
1380 | { |
1381 | hasnull = true; |
1382 | break; |
1383 | } |
1384 | } |
1385 | |
1386 | /* |
1387 | * Determine total space needed |
1388 | */ |
1389 | len = SizeofMinimalTupleHeader; |
1390 | |
1391 | if (hasnull) |
1392 | len += BITMAPLEN(numberOfAttributes); |
1393 | |
1394 | hoff = len = MAXALIGN(len); /* align user data safely */ |
1395 | |
1396 | data_len = heap_compute_data_size(tupleDescriptor, values, isnull); |
1397 | |
1398 | len += data_len; |
1399 | |
1400 | /* |
1401 | * Allocate and zero the space needed. |
1402 | */ |
1403 | tuple = (MinimalTuple) palloc0(len); |
1404 | |
1405 | /* |
1406 | * And fill in the information. |
1407 | */ |
1408 | tuple->t_len = len; |
1409 | HeapTupleHeaderSetNatts(tuple, numberOfAttributes); |
1410 | tuple->t_hoff = hoff + MINIMAL_TUPLE_OFFSET; |
1411 | |
1412 | heap_fill_tuple(tupleDescriptor, |
1413 | values, |
1414 | isnull, |
1415 | (char *) tuple + hoff, |
1416 | data_len, |
1417 | &tuple->t_infomask, |
1418 | (hasnull ? tuple->t_bits : NULL)); |
1419 | |
1420 | return tuple; |
1421 | } |
1422 | |
1423 | /* |
1424 | * heap_free_minimal_tuple |
1425 | */ |
1426 | void |
1427 | heap_free_minimal_tuple(MinimalTuple mtup) |
1428 | { |
1429 | pfree(mtup); |
1430 | } |
1431 | |
1432 | /* |
1433 | * heap_copy_minimal_tuple |
1434 | * copy a MinimalTuple |
1435 | * |
1436 | * The result is allocated in the current memory context. |
1437 | */ |
1438 | MinimalTuple |
1439 | heap_copy_minimal_tuple(MinimalTuple mtup) |
1440 | { |
1441 | MinimalTuple result; |
1442 | |
1443 | result = (MinimalTuple) palloc(mtup->t_len); |
1444 | memcpy(result, mtup, mtup->t_len); |
1445 | return result; |
1446 | } |
1447 | |
1448 | /* |
1449 | * heap_tuple_from_minimal_tuple |
1450 | * create a HeapTuple by copying from a MinimalTuple; |
1451 | * system columns are filled with zeroes |
1452 | * |
1453 | * The result is allocated in the current memory context. |
1454 | * The HeapTuple struct, tuple header, and tuple data are all allocated |
1455 | * as a single palloc() block. |
1456 | */ |
1457 | HeapTuple |
1458 | heap_tuple_from_minimal_tuple(MinimalTuple mtup) |
1459 | { |
1460 | HeapTuple result; |
1461 | uint32 len = mtup->t_len + MINIMAL_TUPLE_OFFSET; |
1462 | |
1463 | result = (HeapTuple) palloc(HEAPTUPLESIZE + len); |
1464 | result->t_len = len; |
1465 | ItemPointerSetInvalid(&(result->t_self)); |
1466 | result->t_tableOid = InvalidOid; |
1467 | result->t_data = (HeapTupleHeader) ((char *) result + HEAPTUPLESIZE); |
1468 | memcpy((char *) result->t_data + MINIMAL_TUPLE_OFFSET, mtup, mtup->t_len); |
1469 | memset(result->t_data, 0, offsetof(HeapTupleHeaderData, t_infomask2)); |
1470 | return result; |
1471 | } |
1472 | |
1473 | /* |
1474 | * minimal_tuple_from_heap_tuple |
1475 | * create a MinimalTuple by copying from a HeapTuple |
1476 | * |
1477 | * The result is allocated in the current memory context. |
1478 | */ |
1479 | MinimalTuple |
1480 | minimal_tuple_from_heap_tuple(HeapTuple htup) |
1481 | { |
1482 | MinimalTuple result; |
1483 | uint32 len; |
1484 | |
1485 | Assert(htup->t_len > MINIMAL_TUPLE_OFFSET); |
1486 | len = htup->t_len - MINIMAL_TUPLE_OFFSET; |
1487 | result = (MinimalTuple) palloc(len); |
1488 | memcpy(result, (char *) htup->t_data + MINIMAL_TUPLE_OFFSET, len); |
1489 | result->t_len = len; |
1490 | return result; |
1491 | } |
1492 | |
1493 | /* |
1494 | * This mainly exists so JIT can inline the definition, but it's also |
1495 | * sometimes useful in debugging sessions. |
1496 | */ |
1497 | size_t |
1498 | varsize_any(void *p) |
1499 | { |
1500 | return VARSIZE_ANY(p); |
1501 | } |
1502 | |