Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * parse_node.c
4 : * various routines that make nodes for querytrees
5 : *
6 : * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/parser/parse_node.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include "access/heapam.h"
18 : #include "access/htup_details.h"
19 : #include "catalog/pg_type.h"
20 : #include "mb/pg_wchar.h"
21 : #include "nodes/makefuncs.h"
22 : #include "nodes/nodeFuncs.h"
23 : #include "parser/parsetree.h"
24 : #include "parser/parse_coerce.h"
25 : #include "parser/parse_expr.h"
26 : #include "parser/parse_relation.h"
27 : #include "utils/builtins.h"
28 : #include "utils/int8.h"
29 : #include "utils/lsyscache.h"
30 : #include "utils/syscache.h"
31 : #include "utils/varbit.h"
32 :
33 :
34 : static void pcb_error_callback(void *arg);
35 :
36 :
37 : /*
38 : * make_parsestate
39 : * Allocate and initialize a new ParseState.
40 : *
41 : * Caller should eventually release the ParseState via free_parsestate().
42 : */
43 : ParseState *
44 59857 : make_parsestate(ParseState *parentParseState)
45 : {
46 : ParseState *pstate;
47 :
48 59857 : pstate = palloc0(sizeof(ParseState));
49 :
50 59857 : pstate->parentParseState = parentParseState;
51 :
52 : /* Fill in fields that don't start at null/false/zero */
53 59857 : pstate->p_next_resno = 1;
54 59857 : pstate->p_resolve_unknowns = true;
55 :
56 59857 : if (parentParseState)
57 : {
58 3932 : pstate->p_sourcetext = parentParseState->p_sourcetext;
59 : /* all hooks are copied from parent */
60 3932 : pstate->p_pre_columnref_hook = parentParseState->p_pre_columnref_hook;
61 3932 : pstate->p_post_columnref_hook = parentParseState->p_post_columnref_hook;
62 3932 : pstate->p_paramref_hook = parentParseState->p_paramref_hook;
63 3932 : pstate->p_coerce_param_hook = parentParseState->p_coerce_param_hook;
64 3932 : pstate->p_ref_hook_state = parentParseState->p_ref_hook_state;
65 : /* query environment stays in context for the whole parse analysis */
66 3932 : pstate->p_queryEnv = parentParseState->p_queryEnv;
67 : }
68 :
69 59857 : return pstate;
70 : }
71 :
72 : /*
73 : * free_parsestate
74 : * Release a ParseState and any subsidiary resources.
75 : */
76 : void
77 53929 : free_parsestate(ParseState *pstate)
78 : {
79 : /*
80 : * Check that we did not produce too many resnos; at the very least we
81 : * cannot allow more than 2^16, since that would exceed the range of a
82 : * AttrNumber. It seems safest to use MaxTupleAttributeNumber.
83 : */
84 53929 : if (pstate->p_next_resno - 1 > MaxTupleAttributeNumber)
85 0 : ereport(ERROR,
86 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
87 : errmsg("target lists can have at most %d entries",
88 : MaxTupleAttributeNumber)));
89 :
90 53929 : if (pstate->p_target_relation != NULL)
91 4335 : heap_close(pstate->p_target_relation, NoLock);
92 :
93 53929 : pfree(pstate);
94 53929 : }
95 :
96 :
97 : /*
98 : * parser_errposition
99 : * Report a parse-analysis-time cursor position, if possible.
100 : *
101 : * This is expected to be used within an ereport() call. The return value
102 : * is a dummy (always 0, in fact).
103 : *
104 : * The locations stored in raw parsetrees are byte offsets into the source
105 : * string. We have to convert them to 1-based character indexes for reporting
106 : * to clients. (We do things this way to avoid unnecessary overhead in the
107 : * normal non-error case: computing character indexes would be much more
108 : * expensive than storing token offsets.)
109 : */
110 : int
111 761 : parser_errposition(ParseState *pstate, int location)
112 : {
113 : int pos;
114 :
115 : /* No-op if location was not provided */
116 761 : if (location < 0)
117 5 : return 0;
118 : /* Can't do anything if source text is not available */
119 756 : if (pstate == NULL || pstate->p_sourcetext == NULL)
120 33 : return 0;
121 : /* Convert offset to character number */
122 723 : pos = pg_mbstrlen_with_len(pstate->p_sourcetext, location) + 1;
123 : /* And pass it to the ereport mechanism */
124 723 : return errposition(pos);
125 : }
126 :
127 :
128 : /*
129 : * setup_parser_errposition_callback
130 : * Arrange for non-parser errors to report an error position
131 : *
132 : * Sometimes the parser calls functions that aren't part of the parser
133 : * subsystem and can't reasonably be passed a ParseState; yet we would
134 : * like any errors thrown in those functions to be tagged with a parse
135 : * error location. Use this function to set up an error context stack
136 : * entry that will accomplish that. Usage pattern:
137 : *
138 : * declare a local variable "ParseCallbackState pcbstate"
139 : * ...
140 : * setup_parser_errposition_callback(&pcbstate, pstate, location);
141 : * call function that might throw error;
142 : * cancel_parser_errposition_callback(&pcbstate);
143 : */
144 : void
145 80212 : setup_parser_errposition_callback(ParseCallbackState *pcbstate,
146 : ParseState *pstate, int location)
147 : {
148 : /* Setup error traceback support for ereport() */
149 80212 : pcbstate->pstate = pstate;
150 80212 : pcbstate->location = location;
151 80212 : pcbstate->errcallback.callback = pcb_error_callback;
152 80212 : pcbstate->errcallback.arg = (void *) pcbstate;
153 80212 : pcbstate->errcallback.previous = error_context_stack;
154 80212 : error_context_stack = &pcbstate->errcallback;
155 80212 : }
156 :
157 : /*
158 : * Cancel a previously-set-up errposition callback.
159 : */
160 : void
161 79764 : cancel_parser_errposition_callback(ParseCallbackState *pcbstate)
162 : {
163 : /* Pop the error context stack */
164 79764 : error_context_stack = pcbstate->errcallback.previous;
165 79764 : }
166 :
167 : /*
168 : * Error context callback for inserting parser error location.
169 : *
170 : * Note that this will be called for *any* error occurring while the
171 : * callback is installed. We avoid inserting an irrelevant error location
172 : * if the error is a query cancel --- are there any other important cases?
173 : */
174 : static void
175 448 : pcb_error_callback(void *arg)
176 : {
177 448 : ParseCallbackState *pcbstate = (ParseCallbackState *) arg;
178 :
179 448 : if (geterrcode() != ERRCODE_QUERY_CANCELED)
180 448 : (void) parser_errposition(pcbstate->pstate, pcbstate->location);
181 448 : }
182 :
183 :
184 : /*
185 : * make_var
186 : * Build a Var node for an attribute identified by RTE and attrno
187 : */
188 : Var *
189 47832 : make_var(ParseState *pstate, RangeTblEntry *rte, int attrno, int location)
190 : {
191 : Var *result;
192 : int vnum,
193 : sublevels_up;
194 : Oid vartypeid;
195 : int32 type_mod;
196 : Oid varcollid;
197 :
198 47832 : vnum = RTERangeTablePosn(pstate, rte, &sublevels_up);
199 47832 : get_rte_attribute_type(rte, attrno, &vartypeid, &type_mod, &varcollid);
200 47832 : result = makeVar(vnum, attrno, vartypeid, type_mod, varcollid, sublevels_up);
201 47832 : result->location = location;
202 47832 : return result;
203 : }
204 :
205 : /*
206 : * transformArrayType()
207 : * Identify the types involved in a subscripting operation
208 : *
209 : * On entry, arrayType/arrayTypmod identify the type of the input value
210 : * to be subscripted (which could be a domain type). These are modified
211 : * if necessary to identify the actual array type and typmod, and the
212 : * array's element type is returned. An error is thrown if the input isn't
213 : * an array type.
214 : */
215 : Oid
216 475 : transformArrayType(Oid *arrayType, int32 *arrayTypmod)
217 : {
218 475 : Oid origArrayType = *arrayType;
219 : Oid elementType;
220 : HeapTuple type_tuple_array;
221 : Form_pg_type type_struct_array;
222 :
223 : /*
224 : * If the input is a domain, smash to base type, and extract the actual
225 : * typmod to be applied to the base type. Subscripting a domain is an
226 : * operation that necessarily works on the base array type, not the domain
227 : * itself. (Note that we provide no method whereby the creator of a
228 : * domain over an array type could hide its ability to be subscripted.)
229 : */
230 475 : *arrayType = getBaseTypeAndTypmod(*arrayType, arrayTypmod);
231 :
232 : /*
233 : * We treat int2vector and oidvector as though they were domains over
234 : * int2[] and oid[]. This is needed because array slicing could create an
235 : * array that doesn't satisfy the dimensionality constraints of the
236 : * xxxvector type; so we want the result of a slice operation to be
237 : * considered to be of the more general type.
238 : */
239 475 : if (*arrayType == INT2VECTOROID)
240 1 : *arrayType = INT2ARRAYOID;
241 474 : else if (*arrayType == OIDVECTOROID)
242 121 : *arrayType = OIDARRAYOID;
243 :
244 : /* Get the type tuple for the array */
245 475 : type_tuple_array = SearchSysCache1(TYPEOID, ObjectIdGetDatum(*arrayType));
246 475 : if (!HeapTupleIsValid(type_tuple_array))
247 0 : elog(ERROR, "cache lookup failed for type %u", *arrayType);
248 475 : type_struct_array = (Form_pg_type) GETSTRUCT(type_tuple_array);
249 :
250 : /* needn't check typisdefined since this will fail anyway */
251 :
252 475 : elementType = type_struct_array->typelem;
253 475 : if (elementType == InvalidOid)
254 0 : ereport(ERROR,
255 : (errcode(ERRCODE_DATATYPE_MISMATCH),
256 : errmsg("cannot subscript type %s because it is not an array",
257 : format_type_be(origArrayType))));
258 :
259 475 : ReleaseSysCache(type_tuple_array);
260 :
261 475 : return elementType;
262 : }
263 :
264 : /*
265 : * transformArraySubscripts()
266 : * Transform array subscripting. This is used for both
267 : * array fetch and array assignment.
268 : *
269 : * In an array fetch, we are given a source array value and we produce an
270 : * expression that represents the result of extracting a single array element
271 : * or an array slice.
272 : *
273 : * In an array assignment, we are given a destination array value plus a
274 : * source value that is to be assigned to a single element or a slice of
275 : * that array. We produce an expression that represents the new array value
276 : * with the source data inserted into the right part of the array.
277 : *
278 : * For both cases, if the source array is of a domain-over-array type,
279 : * the result is of the base array type or its element type; essentially,
280 : * we must fold a domain to its base type before applying subscripting.
281 : * (Note that int2vector and oidvector are treated as domains here.)
282 : *
283 : * pstate Parse state
284 : * arrayBase Already-transformed expression for the array as a whole
285 : * arrayType OID of array's datatype (should match type of arrayBase,
286 : * or be the base type of arrayBase's domain type)
287 : * elementType OID of array's element type (fetch with transformArrayType,
288 : * or pass InvalidOid to do it here)
289 : * arrayTypMod typmod for the array (which is also typmod for the elements)
290 : * indirection Untransformed list of subscripts (must not be NIL)
291 : * assignFrom NULL for array fetch, else transformed expression for source.
292 : */
293 : ArrayRef *
294 475 : transformArraySubscripts(ParseState *pstate,
295 : Node *arrayBase,
296 : Oid arrayType,
297 : Oid elementType,
298 : int32 arrayTypMod,
299 : List *indirection,
300 : Node *assignFrom)
301 : {
302 475 : bool isSlice = false;
303 475 : List *upperIndexpr = NIL;
304 475 : List *lowerIndexpr = NIL;
305 : ListCell *idx;
306 : ArrayRef *aref;
307 :
308 : /*
309 : * Caller may or may not have bothered to determine elementType. Note
310 : * that if the caller did do so, arrayType/arrayTypMod must be as modified
311 : * by transformArrayType, ie, smash domain to base type.
312 : */
313 475 : if (!OidIsValid(elementType))
314 332 : elementType = transformArrayType(&arrayType, &arrayTypMod);
315 :
316 : /*
317 : * A list containing only simple subscripts refers to a single array
318 : * element. If any of the items are slice specifiers (lower:upper), then
319 : * the subscript expression means an array slice operation. In this case,
320 : * we convert any non-slice items to slices by treating the single
321 : * subscript as the upper bound and supplying an assumed lower bound of 1.
322 : * We have to prescan the list to see if there are any slice items.
323 : */
324 911 : foreach(idx, indirection)
325 : {
326 496 : A_Indices *ai = (A_Indices *) lfirst(idx);
327 :
328 496 : if (ai->is_slice)
329 : {
330 60 : isSlice = true;
331 60 : break;
332 : }
333 : }
334 :
335 : /*
336 : * Transform the subscript expressions.
337 : */
338 995 : foreach(idx, indirection)
339 : {
340 520 : A_Indices *ai = lfirst_node(A_Indices, idx);
341 : Node *subexpr;
342 :
343 520 : if (isSlice)
344 : {
345 86 : if (ai->lidx)
346 : {
347 64 : subexpr = transformExpr(pstate, ai->lidx, pstate->p_expr_kind);
348 : /* If it's not int4 already, try to coerce */
349 64 : subexpr = coerce_to_target_type(pstate,
350 : subexpr, exprType(subexpr),
351 : INT4OID, -1,
352 : COERCION_ASSIGNMENT,
353 : COERCE_IMPLICIT_CAST,
354 : -1);
355 64 : if (subexpr == NULL)
356 0 : ereport(ERROR,
357 : (errcode(ERRCODE_DATATYPE_MISMATCH),
358 : errmsg("array subscript must have type integer"),
359 : parser_errposition(pstate, exprLocation(ai->lidx))));
360 : }
361 22 : else if (!ai->is_slice)
362 : {
363 : /* Make a constant 1 */
364 9 : subexpr = (Node *) makeConst(INT4OID,
365 : -1,
366 : InvalidOid,
367 : sizeof(int32),
368 : Int32GetDatum(1),
369 : false,
370 : true); /* pass by value */
371 : }
372 : else
373 : {
374 : /* Slice with omitted lower bound, put NULL into the list */
375 13 : subexpr = NULL;
376 : }
377 86 : lowerIndexpr = lappend(lowerIndexpr, subexpr);
378 : }
379 : else
380 434 : Assert(ai->lidx == NULL && !ai->is_slice);
381 :
382 520 : if (ai->uidx)
383 : {
384 507 : subexpr = transformExpr(pstate, ai->uidx, pstate->p_expr_kind);
385 : /* If it's not int4 already, try to coerce */
386 507 : subexpr = coerce_to_target_type(pstate,
387 : subexpr, exprType(subexpr),
388 : INT4OID, -1,
389 : COERCION_ASSIGNMENT,
390 : COERCE_IMPLICIT_CAST,
391 : -1);
392 507 : if (subexpr == NULL)
393 0 : ereport(ERROR,
394 : (errcode(ERRCODE_DATATYPE_MISMATCH),
395 : errmsg("array subscript must have type integer"),
396 : parser_errposition(pstate, exprLocation(ai->uidx))));
397 : }
398 : else
399 : {
400 : /* Slice with omitted upper bound, put NULL into the list */
401 13 : Assert(isSlice && ai->is_slice);
402 13 : subexpr = NULL;
403 : }
404 520 : upperIndexpr = lappend(upperIndexpr, subexpr);
405 : }
406 :
407 : /*
408 : * If doing an array store, coerce the source value to the right type.
409 : * (This should agree with the coercion done by transformAssignedExpr.)
410 : */
411 475 : if (assignFrom != NULL)
412 : {
413 143 : Oid typesource = exprType(assignFrom);
414 143 : Oid typeneeded = isSlice ? arrayType : elementType;
415 : Node *newFrom;
416 :
417 143 : newFrom = coerce_to_target_type(pstate,
418 : assignFrom, typesource,
419 : typeneeded, arrayTypMod,
420 : COERCION_ASSIGNMENT,
421 : COERCE_IMPLICIT_CAST,
422 : -1);
423 143 : if (newFrom == NULL)
424 0 : ereport(ERROR,
425 : (errcode(ERRCODE_DATATYPE_MISMATCH),
426 : errmsg("array assignment requires type %s"
427 : " but expression is of type %s",
428 : format_type_be(typeneeded),
429 : format_type_be(typesource)),
430 : errhint("You will need to rewrite or cast the expression."),
431 : parser_errposition(pstate, exprLocation(assignFrom))));
432 143 : assignFrom = newFrom;
433 : }
434 :
435 : /*
436 : * Ready to build the ArrayRef node.
437 : */
438 475 : aref = makeNode(ArrayRef);
439 475 : aref->refarraytype = arrayType;
440 475 : aref->refelemtype = elementType;
441 475 : aref->reftypmod = arrayTypMod;
442 : /* refcollid will be set by parse_collate.c */
443 475 : aref->refupperindexpr = upperIndexpr;
444 475 : aref->reflowerindexpr = lowerIndexpr;
445 475 : aref->refexpr = (Expr *) arrayBase;
446 475 : aref->refassgnexpr = (Expr *) assignFrom;
447 :
448 475 : return aref;
449 : }
450 :
451 : /*
452 : * make_const
453 : *
454 : * Convert a Value node (as returned by the grammar) to a Const node
455 : * of the "natural" type for the constant. Note that this routine is
456 : * only used when there is no explicit cast for the constant, so we
457 : * have to guess what type is wanted.
458 : *
459 : * For string literals we produce a constant of type UNKNOWN ---- whose
460 : * representation is the same as cstring, but it indicates to later type
461 : * resolution that we're not sure yet what type it should be considered.
462 : * Explicit "NULL" constants are also typed as UNKNOWN.
463 : *
464 : * For integers and floats we produce int4, int8, or numeric depending
465 : * on the value of the number. XXX We should produce int2 as well,
466 : * but additional cleanup is needed before we can do that; there are
467 : * too many examples that fail if we try.
468 : */
469 : Const *
470 42187 : make_const(ParseState *pstate, Value *value, int location)
471 : {
472 : Const *con;
473 : Datum val;
474 : int64 val64;
475 : Oid typeid;
476 : int typelen;
477 : bool typebyval;
478 : ParseCallbackState pcbstate;
479 :
480 42187 : switch (nodeTag(value))
481 : {
482 : case T_Integer:
483 15061 : val = Int32GetDatum(intVal(value));
484 :
485 15061 : typeid = INT4OID;
486 15061 : typelen = sizeof(int32);
487 15061 : typebyval = true;
488 15061 : break;
489 :
490 : case T_Float:
491 : /* could be an oversize integer as well as a float ... */
492 823 : if (scanint8(strVal(value), true, &val64))
493 : {
494 : /*
495 : * It might actually fit in int32. Probably only INT_MIN can
496 : * occur, but we'll code the test generally just to be sure.
497 : */
498 52 : int32 val32 = (int32) val64;
499 :
500 52 : if (val64 == (int64) val32)
501 : {
502 8 : val = Int32GetDatum(val32);
503 :
504 8 : typeid = INT4OID;
505 8 : typelen = sizeof(int32);
506 8 : typebyval = true;
507 : }
508 : else
509 : {
510 44 : val = Int64GetDatum(val64);
511 :
512 44 : typeid = INT8OID;
513 44 : typelen = sizeof(int64);
514 44 : typebyval = FLOAT8PASSBYVAL; /* int8 and float8 alike */
515 : }
516 : }
517 : else
518 : {
519 : /* arrange to report location if numeric_in() fails */
520 771 : setup_parser_errposition_callback(&pcbstate, pstate, location);
521 771 : val = DirectFunctionCall3(numeric_in,
522 : CStringGetDatum(strVal(value)),
523 : ObjectIdGetDatum(InvalidOid),
524 : Int32GetDatum(-1));
525 771 : cancel_parser_errposition_callback(&pcbstate);
526 :
527 771 : typeid = NUMERICOID;
528 771 : typelen = -1; /* variable len */
529 771 : typebyval = false;
530 : }
531 823 : break;
532 :
533 : case T_String:
534 :
535 : /*
536 : * We assume here that UNKNOWN's internal representation is the
537 : * same as CSTRING
538 : */
539 24008 : val = CStringGetDatum(strVal(value));
540 :
541 24008 : typeid = UNKNOWNOID; /* will be coerced later */
542 24008 : typelen = -2; /* cstring-style varwidth type */
543 24008 : typebyval = false;
544 24008 : break;
545 :
546 : case T_BitString:
547 : /* arrange to report location if bit_in() fails */
548 149 : setup_parser_errposition_callback(&pcbstate, pstate, location);
549 149 : val = DirectFunctionCall3(bit_in,
550 : CStringGetDatum(strVal(value)),
551 : ObjectIdGetDatum(InvalidOid),
552 : Int32GetDatum(-1));
553 149 : cancel_parser_errposition_callback(&pcbstate);
554 149 : typeid = BITOID;
555 149 : typelen = -1;
556 149 : typebyval = false;
557 149 : break;
558 :
559 : case T_Null:
560 : /* return a null const */
561 2146 : con = makeConst(UNKNOWNOID,
562 : -1,
563 : InvalidOid,
564 : -2,
565 : (Datum) 0,
566 : true,
567 : false);
568 2146 : con->location = location;
569 2146 : return con;
570 :
571 : default:
572 0 : elog(ERROR, "unrecognized node type: %d", (int) nodeTag(value));
573 : return NULL; /* keep compiler quiet */
574 : }
575 :
576 40041 : con = makeConst(typeid,
577 : -1, /* typmod -1 is OK for all cases */
578 : InvalidOid, /* all cases are uncollatable types */
579 : typelen,
580 : val,
581 : false,
582 : typebyval);
583 40041 : con->location = location;
584 :
585 40041 : return con;
586 : }
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