1/*-------------------------------------------------------------------------
2 *
3 * parse_coerce.c
4 * handle type coercions/conversions for parser
5 *
6 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/parser/parse_coerce.c
12 *
13 *-------------------------------------------------------------------------
14 */
15#include "postgres.h"
16
17#include "access/htup_details.h"
18#include "catalog/pg_cast.h"
19#include "catalog/pg_class.h"
20#include "catalog/pg_inherits.h"
21#include "catalog/pg_proc.h"
22#include "catalog/pg_type.h"
23#include "nodes/makefuncs.h"
24#include "nodes/nodeFuncs.h"
25#include "parser/parse_coerce.h"
26#include "parser/parse_relation.h"
27#include "parser/parse_type.h"
28#include "utils/builtins.h"
29#include "utils/datum.h"
30#include "utils/lsyscache.h"
31#include "utils/syscache.h"
32#include "utils/typcache.h"
33
34
35static Node *coerce_type_typmod(Node *node,
36 Oid targetTypeId, int32 targetTypMod,
37 CoercionContext ccontext, CoercionForm cformat,
38 int location,
39 bool hideInputCoercion);
40static void hide_coercion_node(Node *node);
41static Node *build_coercion_expression(Node *node,
42 CoercionPathType pathtype,
43 Oid funcId,
44 Oid targetTypeId, int32 targetTypMod,
45 CoercionContext ccontext, CoercionForm cformat,
46 int location);
47static Node *coerce_record_to_complex(ParseState *pstate, Node *node,
48 Oid targetTypeId,
49 CoercionContext ccontext,
50 CoercionForm cformat,
51 int location);
52static bool is_complex_array(Oid typid);
53static bool typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId);
54
55
56/*
57 * coerce_to_target_type()
58 * Convert an expression to a target type and typmod.
59 *
60 * This is the general-purpose entry point for arbitrary type coercion
61 * operations. Direct use of the component operations can_coerce_type,
62 * coerce_type, and coerce_type_typmod should be restricted to special
63 * cases (eg, when the conversion is expected to succeed).
64 *
65 * Returns the possibly-transformed expression tree, or NULL if the type
66 * conversion is not possible. (We do this, rather than ereport'ing directly,
67 * so that callers can generate custom error messages indicating context.)
68 *
69 * pstate - parse state (can be NULL, see coerce_type)
70 * expr - input expression tree (already transformed by transformExpr)
71 * exprtype - result type of expr
72 * targettype - desired result type
73 * targettypmod - desired result typmod
74 * ccontext, cformat - context indicators to control coercions
75 * location - parse location of the coercion request, or -1 if unknown/implicit
76 */
77Node *
78coerce_to_target_type(ParseState *pstate, Node *expr, Oid exprtype,
79 Oid targettype, int32 targettypmod,
80 CoercionContext ccontext,
81 CoercionForm cformat,
82 int location)
83{
84 Node *result;
85 Node *origexpr;
86
87 if (!can_coerce_type(1, &exprtype, &targettype, ccontext))
88 return NULL;
89
90 /*
91 * If the input has a CollateExpr at the top, strip it off, perform the
92 * coercion, and put a new one back on. This is annoying since it
93 * duplicates logic in coerce_type, but if we don't do this then it's too
94 * hard to tell whether coerce_type actually changed anything, and we
95 * *must* know that to avoid possibly calling hide_coercion_node on
96 * something that wasn't generated by coerce_type. Note that if there are
97 * multiple stacked CollateExprs, we just discard all but the topmost.
98 */
99 origexpr = expr;
100 while (expr && IsA(expr, CollateExpr))
101 expr = (Node *) ((CollateExpr *) expr)->arg;
102
103 result = coerce_type(pstate, expr, exprtype,
104 targettype, targettypmod,
105 ccontext, cformat, location);
106
107 /*
108 * If the target is a fixed-length type, it may need a length coercion as
109 * well as a type coercion. If we find ourselves adding both, force the
110 * inner coercion node to implicit display form.
111 */
112 result = coerce_type_typmod(result,
113 targettype, targettypmod,
114 ccontext, cformat, location,
115 (result != expr && !IsA(result, Const)));
116
117 if (expr != origexpr)
118 {
119 /* Reinstall top CollateExpr */
120 CollateExpr *coll = (CollateExpr *) origexpr;
121 CollateExpr *newcoll = makeNode(CollateExpr);
122
123 newcoll->arg = (Expr *) result;
124 newcoll->collOid = coll->collOid;
125 newcoll->location = coll->location;
126 result = (Node *) newcoll;
127 }
128
129 return result;
130}
131
132
133/*
134 * coerce_type()
135 * Convert an expression to a different type.
136 *
137 * The caller should already have determined that the coercion is possible;
138 * see can_coerce_type.
139 *
140 * Normally, no coercion to a typmod (length) is performed here. The caller
141 * must call coerce_type_typmod as well, if a typmod constraint is wanted.
142 * (But if the target type is a domain, it may internally contain a
143 * typmod constraint, which will be applied inside coerce_to_domain.)
144 * In some cases pg_cast specifies a type coercion function that also
145 * applies length conversion, and in those cases only, the result will
146 * already be properly coerced to the specified typmod.
147 *
148 * pstate is only used in the case that we are able to resolve the type of
149 * a previously UNKNOWN Param. It is okay to pass pstate = NULL if the
150 * caller does not want type information updated for Params.
151 *
152 * Note: this function must not modify the given expression tree, only add
153 * decoration on top of it. See transformSetOperationTree, for example.
154 */
155Node *
156coerce_type(ParseState *pstate, Node *node,
157 Oid inputTypeId, Oid targetTypeId, int32 targetTypeMod,
158 CoercionContext ccontext, CoercionForm cformat, int location)
159{
160 Node *result;
161 CoercionPathType pathtype;
162 Oid funcId;
163
164 if (targetTypeId == inputTypeId ||
165 node == NULL)
166 {
167 /* no conversion needed */
168 return node;
169 }
170 if (targetTypeId == ANYOID ||
171 targetTypeId == ANYELEMENTOID ||
172 targetTypeId == ANYNONARRAYOID)
173 {
174 /*
175 * Assume can_coerce_type verified that implicit coercion is okay.
176 *
177 * Note: by returning the unmodified node here, we are saying that
178 * it's OK to treat an UNKNOWN constant as a valid input for a
179 * function accepting ANY, ANYELEMENT, or ANYNONARRAY. This should be
180 * all right, since an UNKNOWN value is still a perfectly valid Datum.
181 *
182 * NB: we do NOT want a RelabelType here: the exposed type of the
183 * function argument must be its actual type, not the polymorphic
184 * pseudotype.
185 */
186 return node;
187 }
188 if (targetTypeId == ANYARRAYOID ||
189 targetTypeId == ANYENUMOID ||
190 targetTypeId == ANYRANGEOID)
191 {
192 /*
193 * Assume can_coerce_type verified that implicit coercion is okay.
194 *
195 * These cases are unlike the ones above because the exposed type of
196 * the argument must be an actual array, enum, or range type. In
197 * particular the argument must *not* be an UNKNOWN constant. If it
198 * is, we just fall through; below, we'll call anyarray_in,
199 * anyenum_in, or anyrange_in, which will produce an error. Also, if
200 * what we have is a domain over array, enum, or range, we have to
201 * relabel it to its base type.
202 *
203 * Note: currently, we can't actually see a domain-over-enum here,
204 * since the other functions in this file will not match such a
205 * parameter to ANYENUM. But that should get changed eventually.
206 */
207 if (inputTypeId != UNKNOWNOID)
208 {
209 Oid baseTypeId = getBaseType(inputTypeId);
210
211 if (baseTypeId != inputTypeId)
212 {
213 RelabelType *r = makeRelabelType((Expr *) node,
214 baseTypeId, -1,
215 InvalidOid,
216 cformat);
217
218 r->location = location;
219 return (Node *) r;
220 }
221 /* Not a domain type, so return it as-is */
222 return node;
223 }
224 }
225 if (inputTypeId == UNKNOWNOID && IsA(node, Const))
226 {
227 /*
228 * Input is a string constant with previously undetermined type. Apply
229 * the target type's typinput function to it to produce a constant of
230 * the target type.
231 *
232 * NOTE: this case cannot be folded together with the other
233 * constant-input case, since the typinput function does not
234 * necessarily behave the same as a type conversion function. For
235 * example, int4's typinput function will reject "1.2", whereas
236 * float-to-int type conversion will round to integer.
237 *
238 * XXX if the typinput function is not immutable, we really ought to
239 * postpone evaluation of the function call until runtime. But there
240 * is no way to represent a typinput function call as an expression
241 * tree, because C-string values are not Datums. (XXX This *is*
242 * possible as of 7.3, do we want to do it?)
243 */
244 Const *con = (Const *) node;
245 Const *newcon = makeNode(Const);
246 Oid baseTypeId;
247 int32 baseTypeMod;
248 int32 inputTypeMod;
249 Type baseType;
250 ParseCallbackState pcbstate;
251
252 /*
253 * If the target type is a domain, we want to call its base type's
254 * input routine, not domain_in(). This is to avoid premature failure
255 * when the domain applies a typmod: existing input routines follow
256 * implicit-coercion semantics for length checks, which is not always
257 * what we want here. The needed check will be applied properly
258 * inside coerce_to_domain().
259 */
260 baseTypeMod = targetTypeMod;
261 baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
262
263 /*
264 * For most types we pass typmod -1 to the input routine, because
265 * existing input routines follow implicit-coercion semantics for
266 * length checks, which is not always what we want here. Any length
267 * constraint will be applied later by our caller. An exception
268 * however is the INTERVAL type, for which we *must* pass the typmod
269 * or it won't be able to obey the bizarre SQL-spec input rules. (Ugly
270 * as sin, but so is this part of the spec...)
271 */
272 if (baseTypeId == INTERVALOID)
273 inputTypeMod = baseTypeMod;
274 else
275 inputTypeMod = -1;
276
277 baseType = typeidType(baseTypeId);
278
279 newcon->consttype = baseTypeId;
280 newcon->consttypmod = inputTypeMod;
281 newcon->constcollid = typeTypeCollation(baseType);
282 newcon->constlen = typeLen(baseType);
283 newcon->constbyval = typeByVal(baseType);
284 newcon->constisnull = con->constisnull;
285
286 /*
287 * We use the original literal's location regardless of the position
288 * of the coercion. This is a change from pre-9.2 behavior, meant to
289 * simplify life for pg_stat_statements.
290 */
291 newcon->location = con->location;
292
293 /*
294 * Set up to point at the constant's text if the input routine throws
295 * an error.
296 */
297 setup_parser_errposition_callback(&pcbstate, pstate, con->location);
298
299 /*
300 * We assume here that UNKNOWN's internal representation is the same
301 * as CSTRING.
302 */
303 if (!con->constisnull)
304 newcon->constvalue = stringTypeDatum(baseType,
305 DatumGetCString(con->constvalue),
306 inputTypeMod);
307 else
308 newcon->constvalue = stringTypeDatum(baseType,
309 NULL,
310 inputTypeMod);
311
312 /*
313 * If it's a varlena value, force it to be in non-expanded
314 * (non-toasted) format; this avoids any possible dependency on
315 * external values and improves consistency of representation.
316 */
317 if (!con->constisnull && newcon->constlen == -1)
318 newcon->constvalue =
319 PointerGetDatum(PG_DETOAST_DATUM(newcon->constvalue));
320
321#ifdef RANDOMIZE_ALLOCATED_MEMORY
322
323 /*
324 * For pass-by-reference data types, repeat the conversion to see if
325 * the input function leaves any uninitialized bytes in the result. We
326 * can only detect that reliably if RANDOMIZE_ALLOCATED_MEMORY is
327 * enabled, so we don't bother testing otherwise. The reason we don't
328 * want any instability in the input function is that comparison of
329 * Const nodes relies on bytewise comparison of the datums, so if the
330 * input function leaves garbage then subexpressions that should be
331 * identical may not get recognized as such. See pgsql-hackers
332 * discussion of 2008-04-04.
333 */
334 if (!con->constisnull && !newcon->constbyval)
335 {
336 Datum val2;
337
338 val2 = stringTypeDatum(baseType,
339 DatumGetCString(con->constvalue),
340 inputTypeMod);
341 if (newcon->constlen == -1)
342 val2 = PointerGetDatum(PG_DETOAST_DATUM(val2));
343 if (!datumIsEqual(newcon->constvalue, val2, false, newcon->constlen))
344 elog(WARNING, "type %s has unstable input conversion for \"%s\"",
345 typeTypeName(baseType), DatumGetCString(con->constvalue));
346 }
347#endif
348
349 cancel_parser_errposition_callback(&pcbstate);
350
351 result = (Node *) newcon;
352
353 /* If target is a domain, apply constraints. */
354 if (baseTypeId != targetTypeId)
355 result = coerce_to_domain(result,
356 baseTypeId, baseTypeMod,
357 targetTypeId,
358 ccontext, cformat, location,
359 false);
360
361 ReleaseSysCache(baseType);
362
363 return result;
364 }
365 if (IsA(node, Param) &&
366 pstate != NULL && pstate->p_coerce_param_hook != NULL)
367 {
368 /*
369 * Allow the CoerceParamHook to decide what happens. It can return a
370 * transformed node (very possibly the same Param node), or return
371 * NULL to indicate we should proceed with normal coercion.
372 */
373 result = pstate->p_coerce_param_hook(pstate,
374 (Param *) node,
375 targetTypeId,
376 targetTypeMod,
377 location);
378 if (result)
379 return result;
380 }
381 if (IsA(node, CollateExpr))
382 {
383 /*
384 * If we have a COLLATE clause, we have to push the coercion
385 * underneath the COLLATE. This is really ugly, but there is little
386 * choice because the above hacks on Consts and Params wouldn't happen
387 * otherwise. This kluge has consequences in coerce_to_target_type.
388 */
389 CollateExpr *coll = (CollateExpr *) node;
390 CollateExpr *newcoll = makeNode(CollateExpr);
391
392 newcoll->arg = (Expr *)
393 coerce_type(pstate, (Node *) coll->arg,
394 inputTypeId, targetTypeId, targetTypeMod,
395 ccontext, cformat, location);
396 newcoll->collOid = coll->collOid;
397 newcoll->location = coll->location;
398 return (Node *) newcoll;
399 }
400 pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext,
401 &funcId);
402 if (pathtype != COERCION_PATH_NONE)
403 {
404 if (pathtype != COERCION_PATH_RELABELTYPE)
405 {
406 /*
407 * Generate an expression tree representing run-time application
408 * of the conversion function. If we are dealing with a domain
409 * target type, the conversion function will yield the base type,
410 * and we need to extract the correct typmod to use from the
411 * domain's typtypmod.
412 */
413 Oid baseTypeId;
414 int32 baseTypeMod;
415
416 baseTypeMod = targetTypeMod;
417 baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
418
419 result = build_coercion_expression(node, pathtype, funcId,
420 baseTypeId, baseTypeMod,
421 ccontext, cformat, location);
422
423 /*
424 * If domain, coerce to the domain type and relabel with domain
425 * type ID, hiding the previous coercion node.
426 */
427 if (targetTypeId != baseTypeId)
428 result = coerce_to_domain(result, baseTypeId, baseTypeMod,
429 targetTypeId,
430 ccontext, cformat, location,
431 true);
432 }
433 else
434 {
435 /*
436 * We don't need to do a physical conversion, but we do need to
437 * attach a RelabelType node so that the expression will be seen
438 * to have the intended type when inspected by higher-level code.
439 *
440 * Also, domains may have value restrictions beyond the base type
441 * that must be accounted for. If the destination is a domain
442 * then we won't need a RelabelType node.
443 */
444 result = coerce_to_domain(node, InvalidOid, -1, targetTypeId,
445 ccontext, cformat, location,
446 false);
447 if (result == node)
448 {
449 /*
450 * XXX could we label result with exprTypmod(node) instead of
451 * default -1 typmod, to save a possible length-coercion
452 * later? Would work if both types have same interpretation of
453 * typmod, which is likely but not certain.
454 */
455 RelabelType *r = makeRelabelType((Expr *) result,
456 targetTypeId, -1,
457 InvalidOid,
458 cformat);
459
460 r->location = location;
461 result = (Node *) r;
462 }
463 }
464 return result;
465 }
466 if (inputTypeId == RECORDOID &&
467 ISCOMPLEX(targetTypeId))
468 {
469 /* Coerce a RECORD to a specific complex type */
470 return coerce_record_to_complex(pstate, node, targetTypeId,
471 ccontext, cformat, location);
472 }
473 if (targetTypeId == RECORDOID &&
474 ISCOMPLEX(inputTypeId))
475 {
476 /* Coerce a specific complex type to RECORD */
477 /* NB: we do NOT want a RelabelType here */
478 return node;
479 }
480#ifdef NOT_USED
481 if (inputTypeId == RECORDARRAYOID &&
482 is_complex_array(targetTypeId))
483 {
484 /* Coerce record[] to a specific complex array type */
485 /* not implemented yet ... */
486 }
487#endif
488 if (targetTypeId == RECORDARRAYOID &&
489 is_complex_array(inputTypeId))
490 {
491 /* Coerce a specific complex array type to record[] */
492 /* NB: we do NOT want a RelabelType here */
493 return node;
494 }
495 if (typeInheritsFrom(inputTypeId, targetTypeId)
496 || typeIsOfTypedTable(inputTypeId, targetTypeId))
497 {
498 /*
499 * Input class type is a subclass of target, so generate an
500 * appropriate runtime conversion (removing unneeded columns and
501 * possibly rearranging the ones that are wanted).
502 *
503 * We will also get here when the input is a domain over a subclass of
504 * the target type. To keep life simple for the executor, we define
505 * ConvertRowtypeExpr as only working between regular composite types;
506 * therefore, in such cases insert a RelabelType to smash the input
507 * expression down to its base type.
508 */
509 Oid baseTypeId = getBaseType(inputTypeId);
510 ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr);
511
512 if (baseTypeId != inputTypeId)
513 {
514 RelabelType *rt = makeRelabelType((Expr *) node,
515 baseTypeId, -1,
516 InvalidOid,
517 COERCE_IMPLICIT_CAST);
518
519 rt->location = location;
520 node = (Node *) rt;
521 }
522 r->arg = (Expr *) node;
523 r->resulttype = targetTypeId;
524 r->convertformat = cformat;
525 r->location = location;
526 return (Node *) r;
527 }
528 /* If we get here, caller blew it */
529 elog(ERROR, "failed to find conversion function from %s to %s",
530 format_type_be(inputTypeId), format_type_be(targetTypeId));
531 return NULL; /* keep compiler quiet */
532}
533
534
535/*
536 * can_coerce_type()
537 * Can input_typeids be coerced to target_typeids?
538 *
539 * We must be told the context (CAST construct, assignment, implicit coercion)
540 * as this determines the set of available casts.
541 */
542bool
543can_coerce_type(int nargs, const Oid *input_typeids, const Oid *target_typeids,
544 CoercionContext ccontext)
545{
546 bool have_generics = false;
547 int i;
548
549 /* run through argument list... */
550 for (i = 0; i < nargs; i++)
551 {
552 Oid inputTypeId = input_typeids[i];
553 Oid targetTypeId = target_typeids[i];
554 CoercionPathType pathtype;
555 Oid funcId;
556
557 /* no problem if same type */
558 if (inputTypeId == targetTypeId)
559 continue;
560
561 /* accept if target is ANY */
562 if (targetTypeId == ANYOID)
563 continue;
564
565 /* accept if target is polymorphic, for now */
566 if (IsPolymorphicType(targetTypeId))
567 {
568 have_generics = true; /* do more checking later */
569 continue;
570 }
571
572 /*
573 * If input is an untyped string constant, assume we can convert it to
574 * anything.
575 */
576 if (inputTypeId == UNKNOWNOID)
577 continue;
578
579 /*
580 * If pg_cast shows that we can coerce, accept. This test now covers
581 * both binary-compatible and coercion-function cases.
582 */
583 pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext,
584 &funcId);
585 if (pathtype != COERCION_PATH_NONE)
586 continue;
587
588 /*
589 * If input is RECORD and target is a composite type, assume we can
590 * coerce (may need tighter checking here)
591 */
592 if (inputTypeId == RECORDOID &&
593 ISCOMPLEX(targetTypeId))
594 continue;
595
596 /*
597 * If input is a composite type and target is RECORD, accept
598 */
599 if (targetTypeId == RECORDOID &&
600 ISCOMPLEX(inputTypeId))
601 continue;
602
603#ifdef NOT_USED /* not implemented yet */
604
605 /*
606 * If input is record[] and target is a composite array type, assume
607 * we can coerce (may need tighter checking here)
608 */
609 if (inputTypeId == RECORDARRAYOID &&
610 is_complex_array(targetTypeId))
611 continue;
612#endif
613
614 /*
615 * If input is a composite array type and target is record[], accept
616 */
617 if (targetTypeId == RECORDARRAYOID &&
618 is_complex_array(inputTypeId))
619 continue;
620
621 /*
622 * If input is a class type that inherits from target, accept
623 */
624 if (typeInheritsFrom(inputTypeId, targetTypeId)
625 || typeIsOfTypedTable(inputTypeId, targetTypeId))
626 continue;
627
628 /*
629 * Else, cannot coerce at this argument position
630 */
631 return false;
632 }
633
634 /* If we found any generic argument types, cross-check them */
635 if (have_generics)
636 {
637 if (!check_generic_type_consistency(input_typeids, target_typeids,
638 nargs))
639 return false;
640 }
641
642 return true;
643}
644
645
646/*
647 * Create an expression tree to represent coercion to a domain type.
648 *
649 * 'arg': input expression
650 * 'baseTypeId': base type of domain, if known (pass InvalidOid if caller
651 * has not bothered to look this up)
652 * 'baseTypeMod': base type typmod of domain, if known (pass -1 if caller
653 * has not bothered to look this up)
654 * 'typeId': target type to coerce to
655 * 'ccontext': context indicator to control coercions
656 * 'cformat': coercion display format
657 * 'location': coercion request location
658 * 'hideInputCoercion': if true, hide the input coercion under this one.
659 *
660 * If the target type isn't a domain, the given 'arg' is returned as-is.
661 */
662Node *
663coerce_to_domain(Node *arg, Oid baseTypeId, int32 baseTypeMod, Oid typeId,
664 CoercionContext ccontext, CoercionForm cformat, int location,
665 bool hideInputCoercion)
666{
667 CoerceToDomain *result;
668
669 /* Get the base type if it hasn't been supplied */
670 if (baseTypeId == InvalidOid)
671 baseTypeId = getBaseTypeAndTypmod(typeId, &baseTypeMod);
672
673 /* If it isn't a domain, return the node as it was passed in */
674 if (baseTypeId == typeId)
675 return arg;
676
677 /* Suppress display of nested coercion steps */
678 if (hideInputCoercion)
679 hide_coercion_node(arg);
680
681 /*
682 * If the domain applies a typmod to its base type, build the appropriate
683 * coercion step. Mark it implicit for display purposes, because we don't
684 * want it shown separately by ruleutils.c; but the isExplicit flag passed
685 * to the conversion function depends on the manner in which the domain
686 * coercion is invoked, so that the semantics of implicit and explicit
687 * coercion differ. (Is that really the behavior we want?)
688 *
689 * NOTE: because we apply this as part of the fixed expression structure,
690 * ALTER DOMAIN cannot alter the typtypmod. But it's unclear that that
691 * would be safe to do anyway, without lots of knowledge about what the
692 * base type thinks the typmod means.
693 */
694 arg = coerce_type_typmod(arg, baseTypeId, baseTypeMod,
695 ccontext, COERCE_IMPLICIT_CAST, location,
696 false);
697
698 /*
699 * Now build the domain coercion node. This represents run-time checking
700 * of any constraints currently attached to the domain. This also ensures
701 * that the expression is properly labeled as to result type.
702 */
703 result = makeNode(CoerceToDomain);
704 result->arg = (Expr *) arg;
705 result->resulttype = typeId;
706 result->resulttypmod = -1; /* currently, always -1 for domains */
707 /* resultcollid will be set by parse_collate.c */
708 result->coercionformat = cformat;
709 result->location = location;
710
711 return (Node *) result;
712}
713
714
715/*
716 * coerce_type_typmod()
717 * Force a value to a particular typmod, if meaningful and possible.
718 *
719 * This is applied to values that are going to be stored in a relation
720 * (where we have an atttypmod for the column) as well as values being
721 * explicitly CASTed (where the typmod comes from the target type spec).
722 *
723 * The caller must have already ensured that the value is of the correct
724 * type, typically by applying coerce_type.
725 *
726 * ccontext may affect semantics, depending on whether the length coercion
727 * function pays attention to the isExplicit flag it's passed.
728 *
729 * cformat determines the display properties of the generated node (if any).
730 *
731 * If hideInputCoercion is true *and* we generate a node, the input node is
732 * forced to IMPLICIT display form, so that only the typmod coercion node will
733 * be visible when displaying the expression.
734 *
735 * NOTE: this does not need to work on domain types, because any typmod
736 * coercion for a domain is considered to be part of the type coercion
737 * needed to produce the domain value in the first place. So, no getBaseType.
738 */
739static Node *
740coerce_type_typmod(Node *node, Oid targetTypeId, int32 targetTypMod,
741 CoercionContext ccontext, CoercionForm cformat,
742 int location,
743 bool hideInputCoercion)
744{
745 CoercionPathType pathtype;
746 Oid funcId;
747
748 /*
749 * A negative typmod is assumed to mean that no coercion is wanted. Also,
750 * skip coercion if already done.
751 */
752 if (targetTypMod < 0 || targetTypMod == exprTypmod(node))
753 return node;
754
755 pathtype = find_typmod_coercion_function(targetTypeId, &funcId);
756
757 if (pathtype != COERCION_PATH_NONE)
758 {
759 /* Suppress display of nested coercion steps */
760 if (hideInputCoercion)
761 hide_coercion_node(node);
762
763 node = build_coercion_expression(node, pathtype, funcId,
764 targetTypeId, targetTypMod,
765 ccontext, cformat, location);
766 }
767
768 return node;
769}
770
771/*
772 * Mark a coercion node as IMPLICIT so it will never be displayed by
773 * ruleutils.c. We use this when we generate a nest of coercion nodes
774 * to implement what is logically one conversion; the inner nodes are
775 * forced to IMPLICIT_CAST format. This does not change their semantics,
776 * only display behavior.
777 *
778 * It is caller error to call this on something that doesn't have a
779 * CoercionForm field.
780 */
781static void
782hide_coercion_node(Node *node)
783{
784 if (IsA(node, FuncExpr))
785 ((FuncExpr *) node)->funcformat = COERCE_IMPLICIT_CAST;
786 else if (IsA(node, RelabelType))
787 ((RelabelType *) node)->relabelformat = COERCE_IMPLICIT_CAST;
788 else if (IsA(node, CoerceViaIO))
789 ((CoerceViaIO *) node)->coerceformat = COERCE_IMPLICIT_CAST;
790 else if (IsA(node, ArrayCoerceExpr))
791 ((ArrayCoerceExpr *) node)->coerceformat = COERCE_IMPLICIT_CAST;
792 else if (IsA(node, ConvertRowtypeExpr))
793 ((ConvertRowtypeExpr *) node)->convertformat = COERCE_IMPLICIT_CAST;
794 else if (IsA(node, RowExpr))
795 ((RowExpr *) node)->row_format = COERCE_IMPLICIT_CAST;
796 else if (IsA(node, CoerceToDomain))
797 ((CoerceToDomain *) node)->coercionformat = COERCE_IMPLICIT_CAST;
798 else
799 elog(ERROR, "unsupported node type: %d", (int) nodeTag(node));
800}
801
802/*
803 * build_coercion_expression()
804 * Construct an expression tree for applying a pg_cast entry.
805 *
806 * This is used for both type-coercion and length-coercion operations,
807 * since there is no difference in terms of the calling convention.
808 */
809static Node *
810build_coercion_expression(Node *node,
811 CoercionPathType pathtype,
812 Oid funcId,
813 Oid targetTypeId, int32 targetTypMod,
814 CoercionContext ccontext, CoercionForm cformat,
815 int location)
816{
817 int nargs = 0;
818
819 if (OidIsValid(funcId))
820 {
821 HeapTuple tp;
822 Form_pg_proc procstruct;
823
824 tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcId));
825 if (!HeapTupleIsValid(tp))
826 elog(ERROR, "cache lookup failed for function %u", funcId);
827 procstruct = (Form_pg_proc) GETSTRUCT(tp);
828
829 /*
830 * These Asserts essentially check that function is a legal coercion
831 * function. We can't make the seemingly obvious tests on prorettype
832 * and proargtypes[0], even in the COERCION_PATH_FUNC case, because of
833 * various binary-compatibility cases.
834 */
835 /* Assert(targetTypeId == procstruct->prorettype); */
836 Assert(!procstruct->proretset);
837 Assert(procstruct->prokind == PROKIND_FUNCTION);
838 nargs = procstruct->pronargs;
839 Assert(nargs >= 1 && nargs <= 3);
840 /* Assert(procstruct->proargtypes.values[0] == exprType(node)); */
841 Assert(nargs < 2 || procstruct->proargtypes.values[1] == INT4OID);
842 Assert(nargs < 3 || procstruct->proargtypes.values[2] == BOOLOID);
843
844 ReleaseSysCache(tp);
845 }
846
847 if (pathtype == COERCION_PATH_FUNC)
848 {
849 /* We build an ordinary FuncExpr with special arguments */
850 FuncExpr *fexpr;
851 List *args;
852 Const *cons;
853
854 Assert(OidIsValid(funcId));
855
856 args = list_make1(node);
857
858 if (nargs >= 2)
859 {
860 /* Pass target typmod as an int4 constant */
861 cons = makeConst(INT4OID,
862 -1,
863 InvalidOid,
864 sizeof(int32),
865 Int32GetDatum(targetTypMod),
866 false,
867 true);
868
869 args = lappend(args, cons);
870 }
871
872 if (nargs == 3)
873 {
874 /* Pass it a boolean isExplicit parameter, too */
875 cons = makeConst(BOOLOID,
876 -1,
877 InvalidOid,
878 sizeof(bool),
879 BoolGetDatum(ccontext == COERCION_EXPLICIT),
880 false,
881 true);
882
883 args = lappend(args, cons);
884 }
885
886 fexpr = makeFuncExpr(funcId, targetTypeId, args,
887 InvalidOid, InvalidOid, cformat);
888 fexpr->location = location;
889 return (Node *) fexpr;
890 }
891 else if (pathtype == COERCION_PATH_ARRAYCOERCE)
892 {
893 /* We need to build an ArrayCoerceExpr */
894 ArrayCoerceExpr *acoerce = makeNode(ArrayCoerceExpr);
895 CaseTestExpr *ctest = makeNode(CaseTestExpr);
896 Oid sourceBaseTypeId;
897 int32 sourceBaseTypeMod;
898 Oid targetElementType;
899 Node *elemexpr;
900
901 /*
902 * Look through any domain over the source array type. Note we don't
903 * expect that the target type is a domain; it must be a plain array.
904 * (To get to a domain target type, we'll do coerce_to_domain later.)
905 */
906 sourceBaseTypeMod = exprTypmod(node);
907 sourceBaseTypeId = getBaseTypeAndTypmod(exprType(node),
908 &sourceBaseTypeMod);
909
910 /*
911 * Set up a CaseTestExpr representing one element of the source array.
912 * This is an abuse of CaseTestExpr, but it's OK as long as there
913 * can't be any CaseExpr or ArrayCoerceExpr within the completed
914 * elemexpr.
915 */
916 ctest->typeId = get_element_type(sourceBaseTypeId);
917 Assert(OidIsValid(ctest->typeId));
918 ctest->typeMod = sourceBaseTypeMod;
919 ctest->collation = InvalidOid; /* Assume coercions don't care */
920
921 /* And coerce it to the target element type */
922 targetElementType = get_element_type(targetTypeId);
923 Assert(OidIsValid(targetElementType));
924
925 elemexpr = coerce_to_target_type(NULL,
926 (Node *) ctest,
927 ctest->typeId,
928 targetElementType,
929 targetTypMod,
930 ccontext,
931 cformat,
932 location);
933 if (elemexpr == NULL) /* shouldn't happen */
934 elog(ERROR, "failed to coerce array element type as expected");
935
936 acoerce->arg = (Expr *) node;
937 acoerce->elemexpr = (Expr *) elemexpr;
938 acoerce->resulttype = targetTypeId;
939
940 /*
941 * Label the output as having a particular element typmod only if we
942 * ended up with a per-element expression that is labeled that way.
943 */
944 acoerce->resulttypmod = exprTypmod(elemexpr);
945 /* resultcollid will be set by parse_collate.c */
946 acoerce->coerceformat = cformat;
947 acoerce->location = location;
948
949 return (Node *) acoerce;
950 }
951 else if (pathtype == COERCION_PATH_COERCEVIAIO)
952 {
953 /* We need to build a CoerceViaIO node */
954 CoerceViaIO *iocoerce = makeNode(CoerceViaIO);
955
956 Assert(!OidIsValid(funcId));
957
958 iocoerce->arg = (Expr *) node;
959 iocoerce->resulttype = targetTypeId;
960 /* resultcollid will be set by parse_collate.c */
961 iocoerce->coerceformat = cformat;
962 iocoerce->location = location;
963
964 return (Node *) iocoerce;
965 }
966 else
967 {
968 elog(ERROR, "unsupported pathtype %d in build_coercion_expression",
969 (int) pathtype);
970 return NULL; /* keep compiler quiet */
971 }
972}
973
974
975/*
976 * coerce_record_to_complex
977 * Coerce a RECORD to a specific composite type.
978 *
979 * Currently we only support this for inputs that are RowExprs or whole-row
980 * Vars.
981 */
982static Node *
983coerce_record_to_complex(ParseState *pstate, Node *node,
984 Oid targetTypeId,
985 CoercionContext ccontext,
986 CoercionForm cformat,
987 int location)
988{
989 RowExpr *rowexpr;
990 Oid baseTypeId;
991 int32 baseTypeMod = -1;
992 TupleDesc tupdesc;
993 List *args = NIL;
994 List *newargs;
995 int i;
996 int ucolno;
997 ListCell *arg;
998
999 if (node && IsA(node, RowExpr))
1000 {
1001 /*
1002 * Since the RowExpr must be of type RECORD, we needn't worry about it
1003 * containing any dropped columns.
1004 */
1005 args = ((RowExpr *) node)->args;
1006 }
1007 else if (node && IsA(node, Var) &&
1008 ((Var *) node)->varattno == InvalidAttrNumber)
1009 {
1010 int rtindex = ((Var *) node)->varno;
1011 int sublevels_up = ((Var *) node)->varlevelsup;
1012 int vlocation = ((Var *) node)->location;
1013 RangeTblEntry *rte;
1014
1015 rte = GetRTEByRangeTablePosn(pstate, rtindex, sublevels_up);
1016 expandRTE(rte, rtindex, sublevels_up, vlocation, false,
1017 NULL, &args);
1018 }
1019 else
1020 ereport(ERROR,
1021 (errcode(ERRCODE_CANNOT_COERCE),
1022 errmsg("cannot cast type %s to %s",
1023 format_type_be(RECORDOID),
1024 format_type_be(targetTypeId)),
1025 parser_coercion_errposition(pstate, location, node)));
1026
1027 /*
1028 * Look up the composite type, accounting for possibility that what we are
1029 * given is a domain over composite.
1030 */
1031 baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
1032 tupdesc = lookup_rowtype_tupdesc(baseTypeId, baseTypeMod);
1033
1034 /* Process the fields */
1035 newargs = NIL;
1036 ucolno = 1;
1037 arg = list_head(args);
1038 for (i = 0; i < tupdesc->natts; i++)
1039 {
1040 Node *expr;
1041 Node *cexpr;
1042 Oid exprtype;
1043 Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
1044
1045 /* Fill in NULLs for dropped columns in rowtype */
1046 if (attr->attisdropped)
1047 {
1048 /*
1049 * can't use atttypid here, but it doesn't really matter what type
1050 * the Const claims to be.
1051 */
1052 newargs = lappend(newargs,
1053 makeNullConst(INT4OID, -1, InvalidOid));
1054 continue;
1055 }
1056
1057 if (arg == NULL)
1058 ereport(ERROR,
1059 (errcode(ERRCODE_CANNOT_COERCE),
1060 errmsg("cannot cast type %s to %s",
1061 format_type_be(RECORDOID),
1062 format_type_be(targetTypeId)),
1063 errdetail("Input has too few columns."),
1064 parser_coercion_errposition(pstate, location, node)));
1065 expr = (Node *) lfirst(arg);
1066 exprtype = exprType(expr);
1067
1068 cexpr = coerce_to_target_type(pstate,
1069 expr, exprtype,
1070 attr->atttypid,
1071 attr->atttypmod,
1072 ccontext,
1073 COERCE_IMPLICIT_CAST,
1074 -1);
1075 if (cexpr == NULL)
1076 ereport(ERROR,
1077 (errcode(ERRCODE_CANNOT_COERCE),
1078 errmsg("cannot cast type %s to %s",
1079 format_type_be(RECORDOID),
1080 format_type_be(targetTypeId)),
1081 errdetail("Cannot cast type %s to %s in column %d.",
1082 format_type_be(exprtype),
1083 format_type_be(attr->atttypid),
1084 ucolno),
1085 parser_coercion_errposition(pstate, location, expr)));
1086 newargs = lappend(newargs, cexpr);
1087 ucolno++;
1088 arg = lnext(arg);
1089 }
1090 if (arg != NULL)
1091 ereport(ERROR,
1092 (errcode(ERRCODE_CANNOT_COERCE),
1093 errmsg("cannot cast type %s to %s",
1094 format_type_be(RECORDOID),
1095 format_type_be(targetTypeId)),
1096 errdetail("Input has too many columns."),
1097 parser_coercion_errposition(pstate, location, node)));
1098
1099 ReleaseTupleDesc(tupdesc);
1100
1101 rowexpr = makeNode(RowExpr);
1102 rowexpr->args = newargs;
1103 rowexpr->row_typeid = baseTypeId;
1104 rowexpr->row_format = cformat;
1105 rowexpr->colnames = NIL; /* not needed for named target type */
1106 rowexpr->location = location;
1107
1108 /* If target is a domain, apply constraints */
1109 if (baseTypeId != targetTypeId)
1110 {
1111 rowexpr->row_format = COERCE_IMPLICIT_CAST;
1112 return coerce_to_domain((Node *) rowexpr,
1113 baseTypeId, baseTypeMod,
1114 targetTypeId,
1115 ccontext, cformat, location,
1116 false);
1117 }
1118
1119 return (Node *) rowexpr;
1120}
1121
1122/*
1123 * coerce_to_boolean()
1124 * Coerce an argument of a construct that requires boolean input
1125 * (AND, OR, NOT, etc). Also check that input is not a set.
1126 *
1127 * Returns the possibly-transformed node tree.
1128 *
1129 * As with coerce_type, pstate may be NULL if no special unknown-Param
1130 * processing is wanted.
1131 */
1132Node *
1133coerce_to_boolean(ParseState *pstate, Node *node,
1134 const char *constructName)
1135{
1136 Oid inputTypeId = exprType(node);
1137
1138 if (inputTypeId != BOOLOID)
1139 {
1140 Node *newnode;
1141
1142 newnode = coerce_to_target_type(pstate, node, inputTypeId,
1143 BOOLOID, -1,
1144 COERCION_ASSIGNMENT,
1145 COERCE_IMPLICIT_CAST,
1146 -1);
1147 if (newnode == NULL)
1148 ereport(ERROR,
1149 (errcode(ERRCODE_DATATYPE_MISMATCH),
1150 /* translator: first %s is name of a SQL construct, eg WHERE */
1151 errmsg("argument of %s must be type %s, not type %s",
1152 constructName, "boolean",
1153 format_type_be(inputTypeId)),
1154 parser_errposition(pstate, exprLocation(node))));
1155 node = newnode;
1156 }
1157
1158 if (expression_returns_set(node))
1159 ereport(ERROR,
1160 (errcode(ERRCODE_DATATYPE_MISMATCH),
1161 /* translator: %s is name of a SQL construct, eg WHERE */
1162 errmsg("argument of %s must not return a set",
1163 constructName),
1164 parser_errposition(pstate, exprLocation(node))));
1165
1166 return node;
1167}
1168
1169/*
1170 * coerce_to_specific_type_typmod()
1171 * Coerce an argument of a construct that requires a specific data type,
1172 * with a specific typmod. Also check that input is not a set.
1173 *
1174 * Returns the possibly-transformed node tree.
1175 *
1176 * As with coerce_type, pstate may be NULL if no special unknown-Param
1177 * processing is wanted.
1178 */
1179Node *
1180coerce_to_specific_type_typmod(ParseState *pstate, Node *node,
1181 Oid targetTypeId, int32 targetTypmod,
1182 const char *constructName)
1183{
1184 Oid inputTypeId = exprType(node);
1185
1186 if (inputTypeId != targetTypeId)
1187 {
1188 Node *newnode;
1189
1190 newnode = coerce_to_target_type(pstate, node, inputTypeId,
1191 targetTypeId, targetTypmod,
1192 COERCION_ASSIGNMENT,
1193 COERCE_IMPLICIT_CAST,
1194 -1);
1195 if (newnode == NULL)
1196 ereport(ERROR,
1197 (errcode(ERRCODE_DATATYPE_MISMATCH),
1198 /* translator: first %s is name of a SQL construct, eg LIMIT */
1199 errmsg("argument of %s must be type %s, not type %s",
1200 constructName,
1201 format_type_be(targetTypeId),
1202 format_type_be(inputTypeId)),
1203 parser_errposition(pstate, exprLocation(node))));
1204 node = newnode;
1205 }
1206
1207 if (expression_returns_set(node))
1208 ereport(ERROR,
1209 (errcode(ERRCODE_DATATYPE_MISMATCH),
1210 /* translator: %s is name of a SQL construct, eg LIMIT */
1211 errmsg("argument of %s must not return a set",
1212 constructName),
1213 parser_errposition(pstate, exprLocation(node))));
1214
1215 return node;
1216}
1217
1218/*
1219 * coerce_to_specific_type()
1220 * Coerce an argument of a construct that requires a specific data type.
1221 * Also check that input is not a set.
1222 *
1223 * Returns the possibly-transformed node tree.
1224 *
1225 * As with coerce_type, pstate may be NULL if no special unknown-Param
1226 * processing is wanted.
1227 */
1228Node *
1229coerce_to_specific_type(ParseState *pstate, Node *node,
1230 Oid targetTypeId,
1231 const char *constructName)
1232{
1233 return coerce_to_specific_type_typmod(pstate, node,
1234 targetTypeId, -1,
1235 constructName);
1236}
1237
1238/*
1239 * parser_coercion_errposition - report coercion error location, if possible
1240 *
1241 * We prefer to point at the coercion request (CAST, ::, etc) if possible;
1242 * but there may be no such location in the case of an implicit coercion.
1243 * In that case point at the input expression.
1244 *
1245 * XXX possibly this is more generally useful than coercion errors;
1246 * if so, should rename and place with parser_errposition.
1247 */
1248int
1249parser_coercion_errposition(ParseState *pstate,
1250 int coerce_location,
1251 Node *input_expr)
1252{
1253 if (coerce_location >= 0)
1254 return parser_errposition(pstate, coerce_location);
1255 else
1256 return parser_errposition(pstate, exprLocation(input_expr));
1257}
1258
1259
1260/*
1261 * select_common_type()
1262 * Determine the common supertype of a list of input expressions.
1263 * This is used for determining the output type of CASE, UNION,
1264 * and similar constructs.
1265 *
1266 * 'exprs' is a *nonempty* list of expressions. Note that earlier items
1267 * in the list will be preferred if there is doubt.
1268 * 'context' is a phrase to use in the error message if we fail to select
1269 * a usable type. Pass NULL to have the routine return InvalidOid
1270 * rather than throwing an error on failure.
1271 * 'which_expr': if not NULL, receives a pointer to the particular input
1272 * expression from which the result type was taken.
1273 */
1274Oid
1275select_common_type(ParseState *pstate, List *exprs, const char *context,
1276 Node **which_expr)
1277{
1278 Node *pexpr;
1279 Oid ptype;
1280 TYPCATEGORY pcategory;
1281 bool pispreferred;
1282 ListCell *lc;
1283
1284 Assert(exprs != NIL);
1285 pexpr = (Node *) linitial(exprs);
1286 lc = lnext(list_head(exprs));
1287 ptype = exprType(pexpr);
1288
1289 /*
1290 * If all input types are valid and exactly the same, just pick that type.
1291 * This is the only way that we will resolve the result as being a domain
1292 * type; otherwise domains are smashed to their base types for comparison.
1293 */
1294 if (ptype != UNKNOWNOID)
1295 {
1296 for_each_cell(lc, lc)
1297 {
1298 Node *nexpr = (Node *) lfirst(lc);
1299 Oid ntype = exprType(nexpr);
1300
1301 if (ntype != ptype)
1302 break;
1303 }
1304 if (lc == NULL) /* got to the end of the list? */
1305 {
1306 if (which_expr)
1307 *which_expr = pexpr;
1308 return ptype;
1309 }
1310 }
1311
1312 /*
1313 * Nope, so set up for the full algorithm. Note that at this point, lc
1314 * points to the first list item with type different from pexpr's; we need
1315 * not re-examine any items the previous loop advanced over.
1316 */
1317 ptype = getBaseType(ptype);
1318 get_type_category_preferred(ptype, &pcategory, &pispreferred);
1319
1320 for_each_cell(lc, lc)
1321 {
1322 Node *nexpr = (Node *) lfirst(lc);
1323 Oid ntype = getBaseType(exprType(nexpr));
1324
1325 /* move on to next one if no new information... */
1326 if (ntype != UNKNOWNOID && ntype != ptype)
1327 {
1328 TYPCATEGORY ncategory;
1329 bool nispreferred;
1330
1331 get_type_category_preferred(ntype, &ncategory, &nispreferred);
1332 if (ptype == UNKNOWNOID)
1333 {
1334 /* so far, only unknowns so take anything... */
1335 pexpr = nexpr;
1336 ptype = ntype;
1337 pcategory = ncategory;
1338 pispreferred = nispreferred;
1339 }
1340 else if (ncategory != pcategory)
1341 {
1342 /*
1343 * both types in different categories? then not much hope...
1344 */
1345 if (context == NULL)
1346 return InvalidOid;
1347 ereport(ERROR,
1348 (errcode(ERRCODE_DATATYPE_MISMATCH),
1349 /*------
1350 translator: first %s is name of a SQL construct, eg CASE */
1351 errmsg("%s types %s and %s cannot be matched",
1352 context,
1353 format_type_be(ptype),
1354 format_type_be(ntype)),
1355 parser_errposition(pstate, exprLocation(nexpr))));
1356 }
1357 else if (!pispreferred &&
1358 can_coerce_type(1, &ptype, &ntype, COERCION_IMPLICIT) &&
1359 !can_coerce_type(1, &ntype, &ptype, COERCION_IMPLICIT))
1360 {
1361 /*
1362 * take new type if can coerce to it implicitly but not the
1363 * other way; but if we have a preferred type, stay on it.
1364 */
1365 pexpr = nexpr;
1366 ptype = ntype;
1367 pcategory = ncategory;
1368 pispreferred = nispreferred;
1369 }
1370 }
1371 }
1372
1373 /*
1374 * If all the inputs were UNKNOWN type --- ie, unknown-type literals ---
1375 * then resolve as type TEXT. This situation comes up with constructs
1376 * like SELECT (CASE WHEN foo THEN 'bar' ELSE 'baz' END); SELECT 'foo'
1377 * UNION SELECT 'bar'; It might seem desirable to leave the construct's
1378 * output type as UNKNOWN, but that really doesn't work, because we'd
1379 * probably end up needing a runtime coercion from UNKNOWN to something
1380 * else, and we usually won't have it. We need to coerce the unknown
1381 * literals while they are still literals, so a decision has to be made
1382 * now.
1383 */
1384 if (ptype == UNKNOWNOID)
1385 ptype = TEXTOID;
1386
1387 if (which_expr)
1388 *which_expr = pexpr;
1389 return ptype;
1390}
1391
1392/*
1393 * coerce_to_common_type()
1394 * Coerce an expression to the given type.
1395 *
1396 * This is used following select_common_type() to coerce the individual
1397 * expressions to the desired type. 'context' is a phrase to use in the
1398 * error message if we fail to coerce.
1399 *
1400 * As with coerce_type, pstate may be NULL if no special unknown-Param
1401 * processing is wanted.
1402 */
1403Node *
1404coerce_to_common_type(ParseState *pstate, Node *node,
1405 Oid targetTypeId, const char *context)
1406{
1407 Oid inputTypeId = exprType(node);
1408
1409 if (inputTypeId == targetTypeId)
1410 return node; /* no work */
1411 if (can_coerce_type(1, &inputTypeId, &targetTypeId, COERCION_IMPLICIT))
1412 node = coerce_type(pstate, node, inputTypeId, targetTypeId, -1,
1413 COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
1414 else
1415 ereport(ERROR,
1416 (errcode(ERRCODE_CANNOT_COERCE),
1417 /* translator: first %s is name of a SQL construct, eg CASE */
1418 errmsg("%s could not convert type %s to %s",
1419 context,
1420 format_type_be(inputTypeId),
1421 format_type_be(targetTypeId)),
1422 parser_errposition(pstate, exprLocation(node))));
1423 return node;
1424}
1425
1426/*
1427 * check_generic_type_consistency()
1428 * Are the actual arguments potentially compatible with a
1429 * polymorphic function?
1430 *
1431 * The argument consistency rules are:
1432 *
1433 * 1) All arguments declared ANYELEMENT must have the same datatype.
1434 * 2) All arguments declared ANYARRAY must have the same datatype,
1435 * which must be a varlena array type.
1436 * 3) All arguments declared ANYRANGE must have the same datatype,
1437 * which must be a range type.
1438 * 4) If there are arguments of both ANYELEMENT and ANYARRAY, make sure the
1439 * actual ANYELEMENT datatype is in fact the element type for the actual
1440 * ANYARRAY datatype.
1441 * 5) Similarly, if there are arguments of both ANYELEMENT and ANYRANGE,
1442 * make sure the actual ANYELEMENT datatype is in fact the subtype for
1443 * the actual ANYRANGE type.
1444 * 6) ANYENUM is treated the same as ANYELEMENT except that if it is used
1445 * (alone or in combination with plain ANYELEMENT), we add the extra
1446 * condition that the ANYELEMENT type must be an enum.
1447 * 7) ANYNONARRAY is treated the same as ANYELEMENT except that if it is used,
1448 * we add the extra condition that the ANYELEMENT type must not be an array.
1449 * (This is a no-op if used in combination with ANYARRAY or ANYENUM, but
1450 * is an extra restriction if not.)
1451 *
1452 * Domains over arrays match ANYARRAY, and are immediately flattened to their
1453 * base type. (Thus, for example, we will consider it a match if one ANYARRAY
1454 * argument is a domain over int4[] while another one is just int4[].) Also
1455 * notice that such a domain does *not* match ANYNONARRAY.
1456 *
1457 * Similarly, domains over ranges match ANYRANGE, and are immediately
1458 * flattened to their base type.
1459 *
1460 * Note that domains aren't currently considered to match ANYENUM,
1461 * even if their base type would match.
1462 *
1463 * If we have UNKNOWN input (ie, an untyped literal) for any polymorphic
1464 * argument, assume it is okay.
1465 *
1466 * If an input is of type ANYARRAY (ie, we know it's an array, but not
1467 * what element type), we will accept it as a match to an argument declared
1468 * ANYARRAY, so long as we don't have to determine an element type ---
1469 * that is, so long as there is no use of ANYELEMENT. This is mostly for
1470 * backwards compatibility with the pre-7.4 behavior of ANYARRAY.
1471 *
1472 * We do not ereport here, but just return false if a rule is violated.
1473 */
1474bool
1475check_generic_type_consistency(const Oid *actual_arg_types,
1476 const Oid *declared_arg_types,
1477 int nargs)
1478{
1479 int j;
1480 Oid elem_typeid = InvalidOid;
1481 Oid array_typeid = InvalidOid;
1482 Oid array_typelem;
1483 Oid range_typeid = InvalidOid;
1484 Oid range_typelem;
1485 bool have_anyelement = false;
1486 bool have_anynonarray = false;
1487 bool have_anyenum = false;
1488
1489 /*
1490 * Loop through the arguments to see if we have any that are polymorphic.
1491 * If so, require the actual types to be consistent.
1492 */
1493 for (j = 0; j < nargs; j++)
1494 {
1495 Oid decl_type = declared_arg_types[j];
1496 Oid actual_type = actual_arg_types[j];
1497
1498 if (decl_type == ANYELEMENTOID ||
1499 decl_type == ANYNONARRAYOID ||
1500 decl_type == ANYENUMOID)
1501 {
1502 have_anyelement = true;
1503 if (decl_type == ANYNONARRAYOID)
1504 have_anynonarray = true;
1505 else if (decl_type == ANYENUMOID)
1506 have_anyenum = true;
1507 if (actual_type == UNKNOWNOID)
1508 continue;
1509 if (OidIsValid(elem_typeid) && actual_type != elem_typeid)
1510 return false;
1511 elem_typeid = actual_type;
1512 }
1513 else if (decl_type == ANYARRAYOID)
1514 {
1515 if (actual_type == UNKNOWNOID)
1516 continue;
1517 actual_type = getBaseType(actual_type); /* flatten domains */
1518 if (OidIsValid(array_typeid) && actual_type != array_typeid)
1519 return false;
1520 array_typeid = actual_type;
1521 }
1522 else if (decl_type == ANYRANGEOID)
1523 {
1524 if (actual_type == UNKNOWNOID)
1525 continue;
1526 actual_type = getBaseType(actual_type); /* flatten domains */
1527 if (OidIsValid(range_typeid) && actual_type != range_typeid)
1528 return false;
1529 range_typeid = actual_type;
1530 }
1531 }
1532
1533 /* Get the element type based on the array type, if we have one */
1534 if (OidIsValid(array_typeid))
1535 {
1536 if (array_typeid == ANYARRAYOID)
1537 {
1538 /* Special case for ANYARRAY input: okay iff no ANYELEMENT */
1539 if (have_anyelement)
1540 return false;
1541 return true;
1542 }
1543
1544 array_typelem = get_element_type(array_typeid);
1545 if (!OidIsValid(array_typelem))
1546 return false; /* should be an array, but isn't */
1547
1548 if (!OidIsValid(elem_typeid))
1549 {
1550 /*
1551 * if we don't have an element type yet, use the one we just got
1552 */
1553 elem_typeid = array_typelem;
1554 }
1555 else if (array_typelem != elem_typeid)
1556 {
1557 /* otherwise, they better match */
1558 return false;
1559 }
1560 }
1561
1562 /* Get the element type based on the range type, if we have one */
1563 if (OidIsValid(range_typeid))
1564 {
1565 range_typelem = get_range_subtype(range_typeid);
1566 if (!OidIsValid(range_typelem))
1567 return false; /* should be a range, but isn't */
1568
1569 if (!OidIsValid(elem_typeid))
1570 {
1571 /*
1572 * if we don't have an element type yet, use the one we just got
1573 */
1574 elem_typeid = range_typelem;
1575 }
1576 else if (range_typelem != elem_typeid)
1577 {
1578 /* otherwise, they better match */
1579 return false;
1580 }
1581 }
1582
1583 if (have_anynonarray)
1584 {
1585 /* require the element type to not be an array or domain over array */
1586 if (type_is_array_domain(elem_typeid))
1587 return false;
1588 }
1589
1590 if (have_anyenum)
1591 {
1592 /* require the element type to be an enum */
1593 if (!type_is_enum(elem_typeid))
1594 return false;
1595 }
1596
1597 /* Looks valid */
1598 return true;
1599}
1600
1601/*
1602 * enforce_generic_type_consistency()
1603 * Make sure a polymorphic function is legally callable, and
1604 * deduce actual argument and result types.
1605 *
1606 * If any polymorphic pseudotype is used in a function's arguments or
1607 * return type, we make sure the actual data types are consistent with
1608 * each other. The argument consistency rules are shown above for
1609 * check_generic_type_consistency().
1610 *
1611 * If we have UNKNOWN input (ie, an untyped literal) for any polymorphic
1612 * argument, we attempt to deduce the actual type it should have. If
1613 * successful, we alter that position of declared_arg_types[] so that
1614 * make_fn_arguments will coerce the literal to the right thing.
1615 *
1616 * Rules are applied to the function's return type (possibly altering it)
1617 * if it is declared as a polymorphic type:
1618 *
1619 * 1) If return type is ANYARRAY, and any argument is ANYARRAY, use the
1620 * argument's actual type as the function's return type.
1621 * 2) Similarly, if return type is ANYRANGE, and any argument is ANYRANGE,
1622 * use the argument's actual type as the function's return type.
1623 * 3) If return type is ANYARRAY, no argument is ANYARRAY, but any argument is
1624 * ANYELEMENT, use the actual type of the argument to determine the
1625 * function's return type, i.e. the element type's corresponding array
1626 * type. (Note: similar behavior does not exist for ANYRANGE, because it's
1627 * impossible to determine the range type from the subtype alone.)
1628 * 4) If return type is ANYARRAY, but no argument is ANYARRAY or ANYELEMENT,
1629 * generate an error. Similarly, if return type is ANYRANGE, but no
1630 * argument is ANYRANGE, generate an error. (These conditions are
1631 * prevented by CREATE FUNCTION and therefore are not expected here.)
1632 * 5) If return type is ANYELEMENT, and any argument is ANYELEMENT, use the
1633 * argument's actual type as the function's return type.
1634 * 6) If return type is ANYELEMENT, no argument is ANYELEMENT, but any argument
1635 * is ANYARRAY or ANYRANGE, use the actual type of the argument to determine
1636 * the function's return type, i.e. the array type's corresponding element
1637 * type or the range type's corresponding subtype (or both, in which case
1638 * they must match).
1639 * 7) If return type is ANYELEMENT, no argument is ANYELEMENT, ANYARRAY, or
1640 * ANYRANGE, generate an error. (This condition is prevented by CREATE
1641 * FUNCTION and therefore is not expected here.)
1642 * 8) ANYENUM is treated the same as ANYELEMENT except that if it is used
1643 * (alone or in combination with plain ANYELEMENT), we add the extra
1644 * condition that the ANYELEMENT type must be an enum.
1645 * 9) ANYNONARRAY is treated the same as ANYELEMENT except that if it is used,
1646 * we add the extra condition that the ANYELEMENT type must not be an array.
1647 * (This is a no-op if used in combination with ANYARRAY or ANYENUM, but
1648 * is an extra restriction if not.)
1649 *
1650 * Domains over arrays or ranges match ANYARRAY or ANYRANGE arguments,
1651 * respectively, and are immediately flattened to their base type. (In
1652 * particular, if the return type is also ANYARRAY or ANYRANGE, we'll set it
1653 * to the base type not the domain type.)
1654 *
1655 * When allow_poly is false, we are not expecting any of the actual_arg_types
1656 * to be polymorphic, and we should not return a polymorphic result type
1657 * either. When allow_poly is true, it is okay to have polymorphic "actual"
1658 * arg types, and we can return ANYARRAY, ANYRANGE, or ANYELEMENT as the
1659 * result. (This case is currently used only to check compatibility of an
1660 * aggregate's declaration with the underlying transfn.)
1661 *
1662 * A special case is that we could see ANYARRAY as an actual_arg_type even
1663 * when allow_poly is false (this is possible only because pg_statistic has
1664 * columns shown as anyarray in the catalogs). We allow this to match a
1665 * declared ANYARRAY argument, but only if there is no ANYELEMENT argument
1666 * or result (since we can't determine a specific element type to match to
1667 * ANYELEMENT). Note this means that functions taking ANYARRAY had better
1668 * behave sanely if applied to the pg_statistic columns; they can't just
1669 * assume that successive inputs are of the same actual element type.
1670 */
1671Oid
1672enforce_generic_type_consistency(const Oid *actual_arg_types,
1673 Oid *declared_arg_types,
1674 int nargs,
1675 Oid rettype,
1676 bool allow_poly)
1677{
1678 int j;
1679 bool have_generics = false;
1680 bool have_unknowns = false;
1681 Oid elem_typeid = InvalidOid;
1682 Oid array_typeid = InvalidOid;
1683 Oid range_typeid = InvalidOid;
1684 Oid array_typelem;
1685 Oid range_typelem;
1686 bool have_anyelement = (rettype == ANYELEMENTOID ||
1687 rettype == ANYNONARRAYOID ||
1688 rettype == ANYENUMOID);
1689 bool have_anynonarray = (rettype == ANYNONARRAYOID);
1690 bool have_anyenum = (rettype == ANYENUMOID);
1691
1692 /*
1693 * Loop through the arguments to see if we have any that are polymorphic.
1694 * If so, require the actual types to be consistent.
1695 */
1696 for (j = 0; j < nargs; j++)
1697 {
1698 Oid decl_type = declared_arg_types[j];
1699 Oid actual_type = actual_arg_types[j];
1700
1701 if (decl_type == ANYELEMENTOID ||
1702 decl_type == ANYNONARRAYOID ||
1703 decl_type == ANYENUMOID)
1704 {
1705 have_generics = have_anyelement = true;
1706 if (decl_type == ANYNONARRAYOID)
1707 have_anynonarray = true;
1708 else if (decl_type == ANYENUMOID)
1709 have_anyenum = true;
1710 if (actual_type == UNKNOWNOID)
1711 {
1712 have_unknowns = true;
1713 continue;
1714 }
1715 if (allow_poly && decl_type == actual_type)
1716 continue; /* no new information here */
1717 if (OidIsValid(elem_typeid) && actual_type != elem_typeid)
1718 ereport(ERROR,
1719 (errcode(ERRCODE_DATATYPE_MISMATCH),
1720 errmsg("arguments declared \"anyelement\" are not all alike"),
1721 errdetail("%s versus %s",
1722 format_type_be(elem_typeid),
1723 format_type_be(actual_type))));
1724 elem_typeid = actual_type;
1725 }
1726 else if (decl_type == ANYARRAYOID)
1727 {
1728 have_generics = true;
1729 if (actual_type == UNKNOWNOID)
1730 {
1731 have_unknowns = true;
1732 continue;
1733 }
1734 if (allow_poly && decl_type == actual_type)
1735 continue; /* no new information here */
1736 actual_type = getBaseType(actual_type); /* flatten domains */
1737 if (OidIsValid(array_typeid) && actual_type != array_typeid)
1738 ereport(ERROR,
1739 (errcode(ERRCODE_DATATYPE_MISMATCH),
1740 errmsg("arguments declared \"anyarray\" are not all alike"),
1741 errdetail("%s versus %s",
1742 format_type_be(array_typeid),
1743 format_type_be(actual_type))));
1744 array_typeid = actual_type;
1745 }
1746 else if (decl_type == ANYRANGEOID)
1747 {
1748 have_generics = true;
1749 if (actual_type == UNKNOWNOID)
1750 {
1751 have_unknowns = true;
1752 continue;
1753 }
1754 if (allow_poly && decl_type == actual_type)
1755 continue; /* no new information here */
1756 actual_type = getBaseType(actual_type); /* flatten domains */
1757 if (OidIsValid(range_typeid) && actual_type != range_typeid)
1758 ereport(ERROR,
1759 (errcode(ERRCODE_DATATYPE_MISMATCH),
1760 errmsg("arguments declared \"anyrange\" are not all alike"),
1761 errdetail("%s versus %s",
1762 format_type_be(range_typeid),
1763 format_type_be(actual_type))));
1764 range_typeid = actual_type;
1765 }
1766 }
1767
1768 /*
1769 * Fast Track: if none of the arguments are polymorphic, return the
1770 * unmodified rettype. We assume it can't be polymorphic either.
1771 */
1772 if (!have_generics)
1773 return rettype;
1774
1775 /* Get the element type based on the array type, if we have one */
1776 if (OidIsValid(array_typeid))
1777 {
1778 if (array_typeid == ANYARRAYOID && !have_anyelement)
1779 {
1780 /* Special case for ANYARRAY input: okay iff no ANYELEMENT */
1781 array_typelem = ANYELEMENTOID;
1782 }
1783 else
1784 {
1785 array_typelem = get_element_type(array_typeid);
1786 if (!OidIsValid(array_typelem))
1787 ereport(ERROR,
1788 (errcode(ERRCODE_DATATYPE_MISMATCH),
1789 errmsg("argument declared %s is not an array but type %s",
1790 "anyarray", format_type_be(array_typeid))));
1791 }
1792
1793 if (!OidIsValid(elem_typeid))
1794 {
1795 /*
1796 * if we don't have an element type yet, use the one we just got
1797 */
1798 elem_typeid = array_typelem;
1799 }
1800 else if (array_typelem != elem_typeid)
1801 {
1802 /* otherwise, they better match */
1803 ereport(ERROR,
1804 (errcode(ERRCODE_DATATYPE_MISMATCH),
1805 errmsg("argument declared %s is not consistent with argument declared %s",
1806 "anyarray", "anyelement"),
1807 errdetail("%s versus %s",
1808 format_type_be(array_typeid),
1809 format_type_be(elem_typeid))));
1810 }
1811 }
1812
1813 /* Get the element type based on the range type, if we have one */
1814 if (OidIsValid(range_typeid))
1815 {
1816 if (range_typeid == ANYRANGEOID && !have_anyelement)
1817 {
1818 /* Special case for ANYRANGE input: okay iff no ANYELEMENT */
1819 range_typelem = ANYELEMENTOID;
1820 }
1821 else
1822 {
1823 range_typelem = get_range_subtype(range_typeid);
1824 if (!OidIsValid(range_typelem))
1825 ereport(ERROR,
1826 (errcode(ERRCODE_DATATYPE_MISMATCH),
1827 errmsg("argument declared %s is not a range type but type %s",
1828 "anyrange",
1829 format_type_be(range_typeid))));
1830 }
1831
1832 if (!OidIsValid(elem_typeid))
1833 {
1834 /*
1835 * if we don't have an element type yet, use the one we just got
1836 */
1837 elem_typeid = range_typelem;
1838 }
1839 else if (range_typelem != elem_typeid)
1840 {
1841 /* otherwise, they better match */
1842 ereport(ERROR,
1843 (errcode(ERRCODE_DATATYPE_MISMATCH),
1844 errmsg("argument declared %s is not consistent with argument declared %s",
1845 "anyrange", "anyelement"),
1846 errdetail("%s versus %s",
1847 format_type_be(range_typeid),
1848 format_type_be(elem_typeid))));
1849 }
1850 }
1851
1852 if (!OidIsValid(elem_typeid))
1853 {
1854 if (allow_poly)
1855 {
1856 elem_typeid = ANYELEMENTOID;
1857 array_typeid = ANYARRAYOID;
1858 range_typeid = ANYRANGEOID;
1859 }
1860 else
1861 {
1862 /* Only way to get here is if all the generic args are UNKNOWN */
1863 ereport(ERROR,
1864 (errcode(ERRCODE_DATATYPE_MISMATCH),
1865 errmsg("could not determine polymorphic type because input has type %s",
1866 "unknown")));
1867 }
1868 }
1869
1870 if (have_anynonarray && elem_typeid != ANYELEMENTOID)
1871 {
1872 /* require the element type to not be an array or domain over array */
1873 if (type_is_array_domain(elem_typeid))
1874 ereport(ERROR,
1875 (errcode(ERRCODE_DATATYPE_MISMATCH),
1876 errmsg("type matched to anynonarray is an array type: %s",
1877 format_type_be(elem_typeid))));
1878 }
1879
1880 if (have_anyenum && elem_typeid != ANYELEMENTOID)
1881 {
1882 /* require the element type to be an enum */
1883 if (!type_is_enum(elem_typeid))
1884 ereport(ERROR,
1885 (errcode(ERRCODE_DATATYPE_MISMATCH),
1886 errmsg("type matched to anyenum is not an enum type: %s",
1887 format_type_be(elem_typeid))));
1888 }
1889
1890 /*
1891 * If we had any unknown inputs, re-scan to assign correct types
1892 */
1893 if (have_unknowns)
1894 {
1895 for (j = 0; j < nargs; j++)
1896 {
1897 Oid decl_type = declared_arg_types[j];
1898 Oid actual_type = actual_arg_types[j];
1899
1900 if (actual_type != UNKNOWNOID)
1901 continue;
1902
1903 if (decl_type == ANYELEMENTOID ||
1904 decl_type == ANYNONARRAYOID ||
1905 decl_type == ANYENUMOID)
1906 declared_arg_types[j] = elem_typeid;
1907 else if (decl_type == ANYARRAYOID)
1908 {
1909 if (!OidIsValid(array_typeid))
1910 {
1911 array_typeid = get_array_type(elem_typeid);
1912 if (!OidIsValid(array_typeid))
1913 ereport(ERROR,
1914 (errcode(ERRCODE_UNDEFINED_OBJECT),
1915 errmsg("could not find array type for data type %s",
1916 format_type_be(elem_typeid))));
1917 }
1918 declared_arg_types[j] = array_typeid;
1919 }
1920 else if (decl_type == ANYRANGEOID)
1921 {
1922 if (!OidIsValid(range_typeid))
1923 {
1924 ereport(ERROR,
1925 (errcode(ERRCODE_UNDEFINED_OBJECT),
1926 errmsg("could not find range type for data type %s",
1927 format_type_be(elem_typeid))));
1928 }
1929 declared_arg_types[j] = range_typeid;
1930 }
1931 }
1932 }
1933
1934 /* if we return ANYARRAY use the appropriate argument type */
1935 if (rettype == ANYARRAYOID)
1936 {
1937 if (!OidIsValid(array_typeid))
1938 {
1939 array_typeid = get_array_type(elem_typeid);
1940 if (!OidIsValid(array_typeid))
1941 ereport(ERROR,
1942 (errcode(ERRCODE_UNDEFINED_OBJECT),
1943 errmsg("could not find array type for data type %s",
1944 format_type_be(elem_typeid))));
1945 }
1946 return array_typeid;
1947 }
1948
1949 /* if we return ANYRANGE use the appropriate argument type */
1950 if (rettype == ANYRANGEOID)
1951 {
1952 if (!OidIsValid(range_typeid))
1953 {
1954 ereport(ERROR,
1955 (errcode(ERRCODE_UNDEFINED_OBJECT),
1956 errmsg("could not find range type for data type %s",
1957 format_type_be(elem_typeid))));
1958 }
1959 return range_typeid;
1960 }
1961
1962 /* if we return ANYELEMENT use the appropriate argument type */
1963 if (rettype == ANYELEMENTOID ||
1964 rettype == ANYNONARRAYOID ||
1965 rettype == ANYENUMOID)
1966 return elem_typeid;
1967
1968 /* we don't return a generic type; send back the original return type */
1969 return rettype;
1970}
1971
1972/*
1973 * resolve_generic_type()
1974 * Deduce an individual actual datatype on the assumption that
1975 * the rules for polymorphic types are being followed.
1976 *
1977 * declared_type is the declared datatype we want to resolve.
1978 * context_actual_type is the actual input datatype to some argument
1979 * that has declared datatype context_declared_type.
1980 *
1981 * If declared_type isn't polymorphic, we just return it. Otherwise,
1982 * context_declared_type must be polymorphic, and we deduce the correct
1983 * return type based on the relationship of the two polymorphic types.
1984 */
1985Oid
1986resolve_generic_type(Oid declared_type,
1987 Oid context_actual_type,
1988 Oid context_declared_type)
1989{
1990 if (declared_type == ANYARRAYOID)
1991 {
1992 if (context_declared_type == ANYARRAYOID)
1993 {
1994 /*
1995 * Use actual type, but it must be an array; or if it's a domain
1996 * over array, use the base array type.
1997 */
1998 Oid context_base_type = getBaseType(context_actual_type);
1999 Oid array_typelem = get_element_type(context_base_type);
2000
2001 if (!OidIsValid(array_typelem))
2002 ereport(ERROR,
2003 (errcode(ERRCODE_DATATYPE_MISMATCH),
2004 errmsg("argument declared %s is not an array but type %s",
2005 "anyarray", format_type_be(context_base_type))));
2006 return context_base_type;
2007 }
2008 else if (context_declared_type == ANYELEMENTOID ||
2009 context_declared_type == ANYNONARRAYOID ||
2010 context_declared_type == ANYENUMOID ||
2011 context_declared_type == ANYRANGEOID)
2012 {
2013 /* Use the array type corresponding to actual type */
2014 Oid array_typeid = get_array_type(context_actual_type);
2015
2016 if (!OidIsValid(array_typeid))
2017 ereport(ERROR,
2018 (errcode(ERRCODE_UNDEFINED_OBJECT),
2019 errmsg("could not find array type for data type %s",
2020 format_type_be(context_actual_type))));
2021 return array_typeid;
2022 }
2023 }
2024 else if (declared_type == ANYELEMENTOID ||
2025 declared_type == ANYNONARRAYOID ||
2026 declared_type == ANYENUMOID ||
2027 declared_type == ANYRANGEOID)
2028 {
2029 if (context_declared_type == ANYARRAYOID)
2030 {
2031 /* Use the element type corresponding to actual type */
2032 Oid context_base_type = getBaseType(context_actual_type);
2033 Oid array_typelem = get_element_type(context_base_type);
2034
2035 if (!OidIsValid(array_typelem))
2036 ereport(ERROR,
2037 (errcode(ERRCODE_DATATYPE_MISMATCH),
2038 errmsg("argument declared %s is not an array but type %s",
2039 "anyarray", format_type_be(context_base_type))));
2040 return array_typelem;
2041 }
2042 else if (context_declared_type == ANYRANGEOID)
2043 {
2044 /* Use the element type corresponding to actual type */
2045 Oid context_base_type = getBaseType(context_actual_type);
2046 Oid range_typelem = get_range_subtype(context_base_type);
2047
2048 if (!OidIsValid(range_typelem))
2049 ereport(ERROR,
2050 (errcode(ERRCODE_DATATYPE_MISMATCH),
2051 errmsg("argument declared %s is not a range type but type %s",
2052 "anyrange", format_type_be(context_base_type))));
2053 return range_typelem;
2054 }
2055 else if (context_declared_type == ANYELEMENTOID ||
2056 context_declared_type == ANYNONARRAYOID ||
2057 context_declared_type == ANYENUMOID)
2058 {
2059 /* Use the actual type; it doesn't matter if array or not */
2060 return context_actual_type;
2061 }
2062 }
2063 else
2064 {
2065 /* declared_type isn't polymorphic, so return it as-is */
2066 return declared_type;
2067 }
2068 /* If we get here, declared_type is polymorphic and context isn't */
2069 /* NB: this is a calling-code logic error, not a user error */
2070 elog(ERROR, "could not determine polymorphic type because context isn't polymorphic");
2071 return InvalidOid; /* keep compiler quiet */
2072}
2073
2074
2075/* TypeCategory()
2076 * Assign a category to the specified type OID.
2077 *
2078 * NB: this must not return TYPCATEGORY_INVALID.
2079 */
2080TYPCATEGORY
2081TypeCategory(Oid type)
2082{
2083 char typcategory;
2084 bool typispreferred;
2085
2086 get_type_category_preferred(type, &typcategory, &typispreferred);
2087 Assert(typcategory != TYPCATEGORY_INVALID);
2088 return (TYPCATEGORY) typcategory;
2089}
2090
2091
2092/* IsPreferredType()
2093 * Check if this type is a preferred type for the given category.
2094 *
2095 * If category is TYPCATEGORY_INVALID, then we'll return true for preferred
2096 * types of any category; otherwise, only for preferred types of that
2097 * category.
2098 */
2099bool
2100IsPreferredType(TYPCATEGORY category, Oid type)
2101{
2102 char typcategory;
2103 bool typispreferred;
2104
2105 get_type_category_preferred(type, &typcategory, &typispreferred);
2106 if (category == typcategory || category == TYPCATEGORY_INVALID)
2107 return typispreferred;
2108 else
2109 return false;
2110}
2111
2112
2113/* IsBinaryCoercible()
2114 * Check if srctype is binary-coercible to targettype.
2115 *
2116 * This notion allows us to cheat and directly exchange values without
2117 * going through the trouble of calling a conversion function. Note that
2118 * in general, this should only be an implementation shortcut. Before 7.4,
2119 * this was also used as a heuristic for resolving overloaded functions and
2120 * operators, but that's basically a bad idea.
2121 *
2122 * As of 7.3, binary coercibility isn't hardwired into the code anymore.
2123 * We consider two types binary-coercible if there is an implicitly
2124 * invokable, no-function-needed pg_cast entry. Also, a domain is always
2125 * binary-coercible to its base type, though *not* vice versa (in the other
2126 * direction, one must apply domain constraint checks before accepting the
2127 * value as legitimate). We also need to special-case various polymorphic
2128 * types.
2129 *
2130 * This function replaces IsBinaryCompatible(), which was an inherently
2131 * symmetric test. Since the pg_cast entries aren't necessarily symmetric,
2132 * the order of the operands is now significant.
2133 */
2134bool
2135IsBinaryCoercible(Oid srctype, Oid targettype)
2136{
2137 HeapTuple tuple;
2138 Form_pg_cast castForm;
2139 bool result;
2140
2141 /* Fast path if same type */
2142 if (srctype == targettype)
2143 return true;
2144
2145 /* Anything is coercible to ANY or ANYELEMENT */
2146 if (targettype == ANYOID || targettype == ANYELEMENTOID)
2147 return true;
2148
2149 /* If srctype is a domain, reduce to its base type */
2150 if (OidIsValid(srctype))
2151 srctype = getBaseType(srctype);
2152
2153 /* Somewhat-fast path for domain -> base type case */
2154 if (srctype == targettype)
2155 return true;
2156
2157 /* Also accept any array type as coercible to ANYARRAY */
2158 if (targettype == ANYARRAYOID)
2159 if (type_is_array(srctype))
2160 return true;
2161
2162 /* Also accept any non-array type as coercible to ANYNONARRAY */
2163 if (targettype == ANYNONARRAYOID)
2164 if (!type_is_array(srctype))
2165 return true;
2166
2167 /* Also accept any enum type as coercible to ANYENUM */
2168 if (targettype == ANYENUMOID)
2169 if (type_is_enum(srctype))
2170 return true;
2171
2172 /* Also accept any range type as coercible to ANYRANGE */
2173 if (targettype == ANYRANGEOID)
2174 if (type_is_range(srctype))
2175 return true;
2176
2177 /* Also accept any composite type as coercible to RECORD */
2178 if (targettype == RECORDOID)
2179 if (ISCOMPLEX(srctype))
2180 return true;
2181
2182 /* Also accept any composite array type as coercible to RECORD[] */
2183 if (targettype == RECORDARRAYOID)
2184 if (is_complex_array(srctype))
2185 return true;
2186
2187 /* Else look in pg_cast */
2188 tuple = SearchSysCache2(CASTSOURCETARGET,
2189 ObjectIdGetDatum(srctype),
2190 ObjectIdGetDatum(targettype));
2191 if (!HeapTupleIsValid(tuple))
2192 return false; /* no cast */
2193 castForm = (Form_pg_cast) GETSTRUCT(tuple);
2194
2195 result = (castForm->castmethod == COERCION_METHOD_BINARY &&
2196 castForm->castcontext == COERCION_CODE_IMPLICIT);
2197
2198 ReleaseSysCache(tuple);
2199
2200 return result;
2201}
2202
2203
2204/*
2205 * find_coercion_pathway
2206 * Look for a coercion pathway between two types.
2207 *
2208 * Currently, this deals only with scalar-type cases; it does not consider
2209 * polymorphic types nor casts between composite types. (Perhaps fold
2210 * those in someday?)
2211 *
2212 * ccontext determines the set of available casts.
2213 *
2214 * The possible result codes are:
2215 * COERCION_PATH_NONE: failed to find any coercion pathway
2216 * *funcid is set to InvalidOid
2217 * COERCION_PATH_FUNC: apply the coercion function returned in *funcid
2218 * COERCION_PATH_RELABELTYPE: binary-compatible cast, no function needed
2219 * *funcid is set to InvalidOid
2220 * COERCION_PATH_ARRAYCOERCE: need an ArrayCoerceExpr node
2221 * *funcid is set to InvalidOid
2222 * COERCION_PATH_COERCEVIAIO: need a CoerceViaIO node
2223 * *funcid is set to InvalidOid
2224 *
2225 * Note: COERCION_PATH_RELABELTYPE does not necessarily mean that no work is
2226 * needed to do the coercion; if the target is a domain then we may need to
2227 * apply domain constraint checking. If you want to check for a zero-effort
2228 * conversion then use IsBinaryCoercible().
2229 */
2230CoercionPathType
2231find_coercion_pathway(Oid targetTypeId, Oid sourceTypeId,
2232 CoercionContext ccontext,
2233 Oid *funcid)
2234{
2235 CoercionPathType result = COERCION_PATH_NONE;
2236 HeapTuple tuple;
2237
2238 *funcid = InvalidOid;
2239
2240 /* Perhaps the types are domains; if so, look at their base types */
2241 if (OidIsValid(sourceTypeId))
2242 sourceTypeId = getBaseType(sourceTypeId);
2243 if (OidIsValid(targetTypeId))
2244 targetTypeId = getBaseType(targetTypeId);
2245
2246 /* Domains are always coercible to and from their base type */
2247 if (sourceTypeId == targetTypeId)
2248 return COERCION_PATH_RELABELTYPE;
2249
2250 /* Look in pg_cast */
2251 tuple = SearchSysCache2(CASTSOURCETARGET,
2252 ObjectIdGetDatum(sourceTypeId),
2253 ObjectIdGetDatum(targetTypeId));
2254
2255 if (HeapTupleIsValid(tuple))
2256 {
2257 Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple);
2258 CoercionContext castcontext;
2259
2260 /* convert char value for castcontext to CoercionContext enum */
2261 switch (castForm->castcontext)
2262 {
2263 case COERCION_CODE_IMPLICIT:
2264 castcontext = COERCION_IMPLICIT;
2265 break;
2266 case COERCION_CODE_ASSIGNMENT:
2267 castcontext = COERCION_ASSIGNMENT;
2268 break;
2269 case COERCION_CODE_EXPLICIT:
2270 castcontext = COERCION_EXPLICIT;
2271 break;
2272 default:
2273 elog(ERROR, "unrecognized castcontext: %d",
2274 (int) castForm->castcontext);
2275 castcontext = 0; /* keep compiler quiet */
2276 break;
2277 }
2278
2279 /* Rely on ordering of enum for correct behavior here */
2280 if (ccontext >= castcontext)
2281 {
2282 switch (castForm->castmethod)
2283 {
2284 case COERCION_METHOD_FUNCTION:
2285 result = COERCION_PATH_FUNC;
2286 *funcid = castForm->castfunc;
2287 break;
2288 case COERCION_METHOD_INOUT:
2289 result = COERCION_PATH_COERCEVIAIO;
2290 break;
2291 case COERCION_METHOD_BINARY:
2292 result = COERCION_PATH_RELABELTYPE;
2293 break;
2294 default:
2295 elog(ERROR, "unrecognized castmethod: %d",
2296 (int) castForm->castmethod);
2297 break;
2298 }
2299 }
2300
2301 ReleaseSysCache(tuple);
2302 }
2303 else
2304 {
2305 /*
2306 * If there's no pg_cast entry, perhaps we are dealing with a pair of
2307 * array types. If so, and if their element types have a conversion
2308 * pathway, report that we can coerce with an ArrayCoerceExpr.
2309 *
2310 * Hack: disallow coercions to oidvector and int2vector, which
2311 * otherwise tend to capture coercions that should go to "real" array
2312 * types. We want those types to be considered "real" arrays for many
2313 * purposes, but not this one. (Also, ArrayCoerceExpr isn't
2314 * guaranteed to produce an output that meets the restrictions of
2315 * these datatypes, such as being 1-dimensional.)
2316 */
2317 if (targetTypeId != OIDVECTOROID && targetTypeId != INT2VECTOROID)
2318 {
2319 Oid targetElem;
2320 Oid sourceElem;
2321
2322 if ((targetElem = get_element_type(targetTypeId)) != InvalidOid &&
2323 (sourceElem = get_element_type(sourceTypeId)) != InvalidOid)
2324 {
2325 CoercionPathType elempathtype;
2326 Oid elemfuncid;
2327
2328 elempathtype = find_coercion_pathway(targetElem,
2329 sourceElem,
2330 ccontext,
2331 &elemfuncid);
2332 if (elempathtype != COERCION_PATH_NONE)
2333 {
2334 result = COERCION_PATH_ARRAYCOERCE;
2335 }
2336 }
2337 }
2338
2339 /*
2340 * If we still haven't found a possibility, consider automatic casting
2341 * using I/O functions. We allow assignment casts to string types and
2342 * explicit casts from string types to be handled this way. (The
2343 * CoerceViaIO mechanism is a lot more general than that, but this is
2344 * all we want to allow in the absence of a pg_cast entry.) It would
2345 * probably be better to insist on explicit casts in both directions,
2346 * but this is a compromise to preserve something of the pre-8.3
2347 * behavior that many types had implicit (yipes!) casts to text.
2348 */
2349 if (result == COERCION_PATH_NONE)
2350 {
2351 if (ccontext >= COERCION_ASSIGNMENT &&
2352 TypeCategory(targetTypeId) == TYPCATEGORY_STRING)
2353 result = COERCION_PATH_COERCEVIAIO;
2354 else if (ccontext >= COERCION_EXPLICIT &&
2355 TypeCategory(sourceTypeId) == TYPCATEGORY_STRING)
2356 result = COERCION_PATH_COERCEVIAIO;
2357 }
2358 }
2359
2360 return result;
2361}
2362
2363
2364/*
2365 * find_typmod_coercion_function -- does the given type need length coercion?
2366 *
2367 * If the target type possesses a pg_cast function from itself to itself,
2368 * it must need length coercion.
2369 *
2370 * "bpchar" (ie, char(N)) and "numeric" are examples of such types.
2371 *
2372 * If the given type is a varlena array type, we do not look for a coercion
2373 * function associated directly with the array type, but instead look for
2374 * one associated with the element type. An ArrayCoerceExpr node must be
2375 * used to apply such a function. (Note: currently, it's pointless to
2376 * return the funcid in this case, because it'll just get looked up again
2377 * in the recursive construction of the ArrayCoerceExpr's elemexpr.)
2378 *
2379 * We use the same result enum as find_coercion_pathway, but the only possible
2380 * result codes are:
2381 * COERCION_PATH_NONE: no length coercion needed
2382 * COERCION_PATH_FUNC: apply the function returned in *funcid
2383 * COERCION_PATH_ARRAYCOERCE: apply the function using ArrayCoerceExpr
2384 */
2385CoercionPathType
2386find_typmod_coercion_function(Oid typeId,
2387 Oid *funcid)
2388{
2389 CoercionPathType result;
2390 Type targetType;
2391 Form_pg_type typeForm;
2392 HeapTuple tuple;
2393
2394 *funcid = InvalidOid;
2395 result = COERCION_PATH_FUNC;
2396
2397 targetType = typeidType(typeId);
2398 typeForm = (Form_pg_type) GETSTRUCT(targetType);
2399
2400 /* Check for a varlena array type */
2401 if (typeForm->typelem != InvalidOid && typeForm->typlen == -1)
2402 {
2403 /* Yes, switch our attention to the element type */
2404 typeId = typeForm->typelem;
2405 result = COERCION_PATH_ARRAYCOERCE;
2406 }
2407 ReleaseSysCache(targetType);
2408
2409 /* Look in pg_cast */
2410 tuple = SearchSysCache2(CASTSOURCETARGET,
2411 ObjectIdGetDatum(typeId),
2412 ObjectIdGetDatum(typeId));
2413
2414 if (HeapTupleIsValid(tuple))
2415 {
2416 Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple);
2417
2418 *funcid = castForm->castfunc;
2419 ReleaseSysCache(tuple);
2420 }
2421
2422 if (!OidIsValid(*funcid))
2423 result = COERCION_PATH_NONE;
2424
2425 return result;
2426}
2427
2428/*
2429 * is_complex_array
2430 * Is this type an array of composite?
2431 *
2432 * Note: this will not return true for record[]; check for RECORDARRAYOID
2433 * separately if needed.
2434 */
2435static bool
2436is_complex_array(Oid typid)
2437{
2438 Oid elemtype = get_element_type(typid);
2439
2440 return (OidIsValid(elemtype) && ISCOMPLEX(elemtype));
2441}
2442
2443
2444/*
2445 * Check whether reltypeId is the row type of a typed table of type
2446 * reloftypeId, or is a domain over such a row type. (This is conceptually
2447 * similar to the subtype relationship checked by typeInheritsFrom().)
2448 */
2449static bool
2450typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId)
2451{
2452 Oid relid = typeOrDomainTypeRelid(reltypeId);
2453 bool result = false;
2454
2455 if (relid)
2456 {
2457 HeapTuple tp;
2458 Form_pg_class reltup;
2459
2460 tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
2461 if (!HeapTupleIsValid(tp))
2462 elog(ERROR, "cache lookup failed for relation %u", relid);
2463
2464 reltup = (Form_pg_class) GETSTRUCT(tp);
2465 if (reltup->reloftype == reloftypeId)
2466 result = true;
2467
2468 ReleaseSysCache(tp);
2469 }
2470
2471 return result;
2472}
2473