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enum.c
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1 /*-------------------------------------------------------------------------
2  *
3  * enum.c
4  * I/O functions, operators, aggregates etc for enum types
5  *
6  * Copyright (c) 2006-2017, PostgreSQL Global Development Group
7  *
8  *
9  * IDENTIFICATION
10  * src/backend/utils/adt/enum.c
11  *
12  *-------------------------------------------------------------------------
13  */
14 #include "postgres.h"
15 
16 #include "access/genam.h"
17 #include "access/heapam.h"
18 #include "access/htup_details.h"
19 #include "catalog/indexing.h"
20 #include "catalog/pg_enum.h"
21 #include "libpq/pqformat.h"
22 #include "utils/array.h"
23 #include "utils/builtins.h"
24 #include "utils/fmgroids.h"
25 #include "utils/snapmgr.h"
26 #include "utils/syscache.h"
27 #include "utils/typcache.h"
28 
29 
30 static Oid enum_endpoint(Oid enumtypoid, ScanDirection direction);
31 static ArrayType *enum_range_internal(Oid enumtypoid, Oid lower, Oid upper);
32 
33 
34 /* Basic I/O support */
35 
36 Datum
38 {
39  char *name = PG_GETARG_CSTRING(0);
40  Oid enumtypoid = PG_GETARG_OID(1);
41  Oid enumoid;
42  HeapTuple tup;
43 
44  /* must check length to prevent Assert failure within SearchSysCache */
45  if (strlen(name) >= NAMEDATALEN)
46  ereport(ERROR,
47  (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
48  errmsg("invalid input value for enum %s: \"%s\"",
49  format_type_be(enumtypoid),
50  name)));
51 
53  ObjectIdGetDatum(enumtypoid),
54  CStringGetDatum(name));
55  if (!HeapTupleIsValid(tup))
56  ereport(ERROR,
57  (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
58  errmsg("invalid input value for enum %s: \"%s\"",
59  format_type_be(enumtypoid),
60  name)));
61 
62  /*
63  * This comes from pg_enum.oid and stores system oids in user tables. This
64  * oid must be preserved by binary upgrades.
65  */
66  enumoid = HeapTupleGetOid(tup);
67 
68  ReleaseSysCache(tup);
69 
70  PG_RETURN_OID(enumoid);
71 }
72 
73 Datum
75 {
76  Oid enumval = PG_GETARG_OID(0);
77  char *result;
78  HeapTuple tup;
79  Form_pg_enum en;
80 
81  tup = SearchSysCache1(ENUMOID, ObjectIdGetDatum(enumval));
82  if (!HeapTupleIsValid(tup))
83  ereport(ERROR,
84  (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
85  errmsg("invalid internal value for enum: %u",
86  enumval)));
87  en = (Form_pg_enum) GETSTRUCT(tup);
88 
89  result = pstrdup(NameStr(en->enumlabel));
90 
91  ReleaseSysCache(tup);
92 
93  PG_RETURN_CSTRING(result);
94 }
95 
96 /* Binary I/O support */
97 Datum
99 {
101  Oid enumtypoid = PG_GETARG_OID(1);
102  Oid enumoid;
103  HeapTuple tup;
104  char *name;
105  int nbytes;
106 
107  name = pq_getmsgtext(buf, buf->len - buf->cursor, &nbytes);
108 
109  /* must check length to prevent Assert failure within SearchSysCache */
110  if (strlen(name) >= NAMEDATALEN)
111  ereport(ERROR,
112  (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
113  errmsg("invalid input value for enum %s: \"%s\"",
114  format_type_be(enumtypoid),
115  name)));
116 
118  ObjectIdGetDatum(enumtypoid),
119  CStringGetDatum(name));
120  if (!HeapTupleIsValid(tup))
121  ereport(ERROR,
122  (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
123  errmsg("invalid input value for enum %s: \"%s\"",
124  format_type_be(enumtypoid),
125  name)));
126 
127  enumoid = HeapTupleGetOid(tup);
128 
129  ReleaseSysCache(tup);
130 
131  pfree(name);
132 
133  PG_RETURN_OID(enumoid);
134 }
135 
136 Datum
138 {
139  Oid enumval = PG_GETARG_OID(0);
141  HeapTuple tup;
142  Form_pg_enum en;
143 
144  tup = SearchSysCache1(ENUMOID, ObjectIdGetDatum(enumval));
145  if (!HeapTupleIsValid(tup))
146  ereport(ERROR,
147  (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
148  errmsg("invalid internal value for enum: %u",
149  enumval)));
150  en = (Form_pg_enum) GETSTRUCT(tup);
151 
152  pq_begintypsend(&buf);
153  pq_sendtext(&buf, NameStr(en->enumlabel), strlen(NameStr(en->enumlabel)));
154 
155  ReleaseSysCache(tup);
156 
158 }
159 
160 /* Comparison functions and related */
161 
162 /*
163  * enum_cmp_internal is the common engine for all the visible comparison
164  * functions, except for enum_eq and enum_ne which can just check for OID
165  * equality directly.
166  */
167 static int
169 {
170  TypeCacheEntry *tcache;
171 
172  /*
173  * We don't need the typcache except in the hopefully-uncommon case that
174  * one or both Oids are odd. This means that cursory testing of code that
175  * fails to pass flinfo to an enum comparison function might not disclose
176  * the oversight. To make such errors more obvious, Assert that we have a
177  * place to cache even when we take a fast-path exit.
178  */
179  Assert(fcinfo->flinfo != NULL);
180 
181  /* Equal OIDs are equal no matter what */
182  if (arg1 == arg2)
183  return 0;
184 
185  /* Fast path: even-numbered Oids are known to compare correctly */
186  if ((arg1 & 1) == 0 && (arg2 & 1) == 0)
187  {
188  if (arg1 < arg2)
189  return -1;
190  else
191  return 1;
192  }
193 
194  /* Locate the typcache entry for the enum type */
195  tcache = (TypeCacheEntry *) fcinfo->flinfo->fn_extra;
196  if (tcache == NULL)
197  {
198  HeapTuple enum_tup;
199  Form_pg_enum en;
200  Oid typeoid;
201 
202  /* Get the OID of the enum type containing arg1 */
203  enum_tup = SearchSysCache1(ENUMOID, ObjectIdGetDatum(arg1));
204  if (!HeapTupleIsValid(enum_tup))
205  ereport(ERROR,
206  (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
207  errmsg("invalid internal value for enum: %u",
208  arg1)));
209  en = (Form_pg_enum) GETSTRUCT(enum_tup);
210  typeoid = en->enumtypid;
211  ReleaseSysCache(enum_tup);
212  /* Now locate and remember the typcache entry */
213  tcache = lookup_type_cache(typeoid, 0);
214  fcinfo->flinfo->fn_extra = (void *) tcache;
215  }
216 
217  /* The remaining comparison logic is in typcache.c */
218  return compare_values_of_enum(tcache, arg1, arg2);
219 }
220 
221 Datum
223 {
224  Oid a = PG_GETARG_OID(0);
225  Oid b = PG_GETARG_OID(1);
226 
227  PG_RETURN_BOOL(enum_cmp_internal(a, b, fcinfo) < 0);
228 }
229 
230 Datum
232 {
233  Oid a = PG_GETARG_OID(0);
234  Oid b = PG_GETARG_OID(1);
235 
236  PG_RETURN_BOOL(enum_cmp_internal(a, b, fcinfo) <= 0);
237 }
238 
239 Datum
241 {
242  Oid a = PG_GETARG_OID(0);
243  Oid b = PG_GETARG_OID(1);
244 
245  PG_RETURN_BOOL(a == b);
246 }
247 
248 Datum
250 {
251  Oid a = PG_GETARG_OID(0);
252  Oid b = PG_GETARG_OID(1);
253 
254  PG_RETURN_BOOL(a != b);
255 }
256 
257 Datum
259 {
260  Oid a = PG_GETARG_OID(0);
261  Oid b = PG_GETARG_OID(1);
262 
263  PG_RETURN_BOOL(enum_cmp_internal(a, b, fcinfo) >= 0);
264 }
265 
266 Datum
268 {
269  Oid a = PG_GETARG_OID(0);
270  Oid b = PG_GETARG_OID(1);
271 
272  PG_RETURN_BOOL(enum_cmp_internal(a, b, fcinfo) > 0);
273 }
274 
275 Datum
277 {
278  Oid a = PG_GETARG_OID(0);
279  Oid b = PG_GETARG_OID(1);
280 
281  PG_RETURN_OID(enum_cmp_internal(a, b, fcinfo) < 0 ? a : b);
282 }
283 
284 Datum
286 {
287  Oid a = PG_GETARG_OID(0);
288  Oid b = PG_GETARG_OID(1);
289 
290  PG_RETURN_OID(enum_cmp_internal(a, b, fcinfo) > 0 ? a : b);
291 }
292 
293 Datum
295 {
296  Oid a = PG_GETARG_OID(0);
297  Oid b = PG_GETARG_OID(1);
298 
299  PG_RETURN_INT32(enum_cmp_internal(a, b, fcinfo));
300 }
301 
302 /* Enum programming support functions */
303 
304 /*
305  * enum_endpoint: common code for enum_first/enum_last
306  */
307 static Oid
308 enum_endpoint(Oid enumtypoid, ScanDirection direction)
309 {
310  Relation enum_rel;
311  Relation enum_idx;
312  SysScanDesc enum_scan;
313  HeapTuple enum_tuple;
314  ScanKeyData skey;
315  Oid minmax;
316 
317  /*
318  * Find the first/last enum member using pg_enum_typid_sortorder_index.
319  * Note we must not use the syscache. See comments for RenumberEnumType
320  * in catalog/pg_enum.c for more info.
321  */
322  ScanKeyInit(&skey,
324  BTEqualStrategyNumber, F_OIDEQ,
325  ObjectIdGetDatum(enumtypoid));
326 
329  enum_scan = systable_beginscan_ordered(enum_rel, enum_idx, NULL,
330  1, &skey);
331 
332  enum_tuple = systable_getnext_ordered(enum_scan, direction);
333  if (HeapTupleIsValid(enum_tuple))
334  minmax = HeapTupleGetOid(enum_tuple);
335  else
336  minmax = InvalidOid;
337 
338  systable_endscan_ordered(enum_scan);
339  index_close(enum_idx, AccessShareLock);
340  heap_close(enum_rel, AccessShareLock);
341 
342  return minmax;
343 }
344 
345 Datum
347 {
348  Oid enumtypoid;
349  Oid min;
350 
351  /*
352  * We rely on being able to get the specific enum type from the calling
353  * expression tree. Notice that the actual value of the argument isn't
354  * examined at all; in particular it might be NULL.
355  */
356  enumtypoid = get_fn_expr_argtype(fcinfo->flinfo, 0);
357  if (enumtypoid == InvalidOid)
358  ereport(ERROR,
359  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
360  errmsg("could not determine actual enum type")));
361 
362  /* Get the OID using the index */
363  min = enum_endpoint(enumtypoid, ForwardScanDirection);
364 
365  if (!OidIsValid(min))
366  ereport(ERROR,
367  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
368  errmsg("enum %s contains no values",
369  format_type_be(enumtypoid))));
370 
371  PG_RETURN_OID(min);
372 }
373 
374 Datum
376 {
377  Oid enumtypoid;
378  Oid max;
379 
380  /*
381  * We rely on being able to get the specific enum type from the calling
382  * expression tree. Notice that the actual value of the argument isn't
383  * examined at all; in particular it might be NULL.
384  */
385  enumtypoid = get_fn_expr_argtype(fcinfo->flinfo, 0);
386  if (enumtypoid == InvalidOid)
387  ereport(ERROR,
388  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
389  errmsg("could not determine actual enum type")));
390 
391  /* Get the OID using the index */
392  max = enum_endpoint(enumtypoid, BackwardScanDirection);
393 
394  if (!OidIsValid(max))
395  ereport(ERROR,
396  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
397  errmsg("enum %s contains no values",
398  format_type_be(enumtypoid))));
399 
400  PG_RETURN_OID(max);
401 }
402 
403 /* 2-argument variant of enum_range */
404 Datum
406 {
407  Oid lower;
408  Oid upper;
409  Oid enumtypoid;
410 
411  if (PG_ARGISNULL(0))
412  lower = InvalidOid;
413  else
414  lower = PG_GETARG_OID(0);
415  if (PG_ARGISNULL(1))
416  upper = InvalidOid;
417  else
418  upper = PG_GETARG_OID(1);
419 
420  /*
421  * We rely on being able to get the specific enum type from the calling
422  * expression tree. The generic type mechanism should have ensured that
423  * both are of the same type.
424  */
425  enumtypoid = get_fn_expr_argtype(fcinfo->flinfo, 0);
426  if (enumtypoid == InvalidOid)
427  ereport(ERROR,
428  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
429  errmsg("could not determine actual enum type")));
430 
431  PG_RETURN_ARRAYTYPE_P(enum_range_internal(enumtypoid, lower, upper));
432 }
433 
434 /* 1-argument variant of enum_range */
435 Datum
437 {
438  Oid enumtypoid;
439 
440  /*
441  * We rely on being able to get the specific enum type from the calling
442  * expression tree. Notice that the actual value of the argument isn't
443  * examined at all; in particular it might be NULL.
444  */
445  enumtypoid = get_fn_expr_argtype(fcinfo->flinfo, 0);
446  if (enumtypoid == InvalidOid)
447  ereport(ERROR,
448  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
449  errmsg("could not determine actual enum type")));
450 
453 }
454 
455 static ArrayType *
457 {
458  ArrayType *result;
459  Relation enum_rel;
460  Relation enum_idx;
461  SysScanDesc enum_scan;
462  HeapTuple enum_tuple;
463  ScanKeyData skey;
464  Datum *elems;
465  int max,
466  cnt;
467  bool left_found;
468 
469  /*
470  * Scan the enum members in order using pg_enum_typid_sortorder_index.
471  * Note we must not use the syscache. See comments for RenumberEnumType
472  * in catalog/pg_enum.c for more info.
473  */
474  ScanKeyInit(&skey,
476  BTEqualStrategyNumber, F_OIDEQ,
477  ObjectIdGetDatum(enumtypoid));
478 
481  enum_scan = systable_beginscan_ordered(enum_rel, enum_idx, NULL, 1, &skey);
482 
483  max = 64;
484  elems = (Datum *) palloc(max * sizeof(Datum));
485  cnt = 0;
486  left_found = !OidIsValid(lower);
487 
488  while (HeapTupleIsValid(enum_tuple = systable_getnext_ordered(enum_scan, ForwardScanDirection)))
489  {
490  Oid enum_oid = HeapTupleGetOid(enum_tuple);
491 
492  if (!left_found && lower == enum_oid)
493  left_found = true;
494 
495  if (left_found)
496  {
497  if (cnt >= max)
498  {
499  max *= 2;
500  elems = (Datum *) repalloc(elems, max * sizeof(Datum));
501  }
502 
503  elems[cnt++] = ObjectIdGetDatum(enum_oid);
504  }
505 
506  if (OidIsValid(upper) && upper == enum_oid)
507  break;
508  }
509 
510  systable_endscan_ordered(enum_scan);
511  index_close(enum_idx, AccessShareLock);
512  heap_close(enum_rel, AccessShareLock);
513 
514  /* and build the result array */
515  /* note this hardwires some details about the representation of Oid */
516  result = construct_array(elems, cnt, enumtypoid, sizeof(Oid), true, 'i');
517 
518  pfree(elems);
519 
520  return result;
521 }
int compare_values_of_enum(TypeCacheEntry *tcache, Oid arg1, Oid arg2)
Definition: typcache.c:2154
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Definition: htup_details.h:661
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Definition: enum.c:98
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Definition: enum.c:456
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Definition: enum.c:308
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