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format_type.c
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1 /*-------------------------------------------------------------------------
2  *
3  * format_type.c
4  * Display type names "nicely".
5  *
6  *
7  * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
8  * Portions Copyright (c) 1994, Regents of the University of California
9  *
10  * IDENTIFICATION
11  * src/backend/utils/adt/format_type.c
12  *
13  *-------------------------------------------------------------------------
14  */
15 
16 #include "postgres.h"
17 
18 #include <ctype.h>
19 
20 #include "access/htup_details.h"
21 #include "catalog/namespace.h"
22 #include "catalog/pg_type.h"
23 #include "mb/pg_wchar.h"
24 #include "utils/builtins.h"
25 #include "utils/fmgroids.h"
26 #include "utils/lsyscache.h"
27 #include "utils/numeric.h"
28 #include "utils/syscache.h"
29 
30 static char *printTypmod(const char *typname, int32 typmod, Oid typmodout);
31 
32 
33 /*
34  * SQL function: format_type(type_oid, typemod)
35  *
36  * `type_oid' is from pg_type.oid, `typemod' is from
37  * pg_attribute.atttypmod. This function will get the type name and
38  * format it and the modifier to canonical SQL format, if the type is
39  * a standard type. Otherwise you just get pg_type.typname back,
40  * double quoted if it contains funny characters or matches a keyword.
41  *
42  * If typemod is NULL then we are formatting a type name in a context where
43  * no typemod is available, eg a function argument or result type. This
44  * yields a slightly different result from specifying typemod = -1 in some
45  * cases. Given typemod = -1 we feel compelled to produce an output that
46  * the parser will interpret as having typemod -1, so that pg_dump will
47  * produce CREATE TABLE commands that recreate the original state. But
48  * given NULL typemod, we assume that the parser's interpretation of
49  * typemod doesn't matter, and so we are willing to output a slightly
50  * "prettier" representation of the same type. For example, type = bpchar
51  * and typemod = NULL gets you "character", whereas typemod = -1 gets you
52  * "bpchar" --- the former will be interpreted as character(1) by the
53  * parser, which does not yield typemod -1.
54  *
55  * XXX encoding a meaning in typemod = NULL is ugly; it'd have been
56  * cleaner to make two functions of one and two arguments respectively.
57  * Not worth changing it now, however.
58  */
59 Datum
61 {
62  Oid type_oid;
63  int32 typemod;
64  char *result;
66 
67  /* Since this function is not strict, we must test for null args */
68  if (PG_ARGISNULL(0))
70 
71  type_oid = PG_GETARG_OID(0);
72 
73  if (PG_ARGISNULL(1))
74  typemod = -1;
75  else
76  {
77  typemod = PG_GETARG_INT32(1);
79  }
80 
81  result = format_type_extended(type_oid, typemod, flags);
82 
84 }
85 
86 /*
87  * format_type_extended
88  * Generate a possibly-qualified type name.
89  *
90  * The default behavior is to only qualify if the type is not in the search
91  * path, to ignore the given typmod, and to raise an error if a non-existent
92  * type_oid is given.
93  *
94  * The following bits in 'flags' modify the behavior:
95  * - FORMAT_TYPE_TYPEMOD_GIVEN
96  * include the typmod in the output (typmod could still be -1 though)
97  * - FORMAT_TYPE_ALLOW_INVALID
98  * if the type OID is invalid or unknown, return ??? or such instead
99  * of failing
100  * - FORMAT_TYPE_INVALID_AS_NULL
101  * if the type OID is invalid or unknown, return NULL instead of ???
102  * or such
103  * - FORMAT_TYPE_FORCE_QUALIFY
104  * always schema-qualify type names, regardless of search_path
105  *
106  * Note that TYPEMOD_GIVEN is not interchangeable with "typemod == -1";
107  * see the comments above for format_type().
108  *
109  * Returns a palloc'd string, or NULL.
110  */
111 char *
112 format_type_extended(Oid type_oid, int32 typemod, bits16 flags)
113 {
114  HeapTuple tuple;
115  Form_pg_type typeform;
116  Oid array_base_type;
117  bool is_array;
118  char *buf;
119  bool with_typemod;
120 
121  if (type_oid == InvalidOid)
122  {
123  if ((flags & FORMAT_TYPE_INVALID_AS_NULL) != 0)
124  return NULL;
125  else if ((flags & FORMAT_TYPE_ALLOW_INVALID) != 0)
126  return pstrdup("-");
127  }
128 
129  tuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type_oid));
130  if (!HeapTupleIsValid(tuple))
131  {
132  if ((flags & FORMAT_TYPE_INVALID_AS_NULL) != 0)
133  return NULL;
134  else if ((flags & FORMAT_TYPE_ALLOW_INVALID) != 0)
135  return pstrdup("???");
136  else
137  elog(ERROR, "cache lookup failed for type %u", type_oid);
138  }
139  typeform = (Form_pg_type) GETSTRUCT(tuple);
140 
141  /*
142  * Check if it's a "true" array type. Pseudo-array types such as "name"
143  * shouldn't get deconstructed. Also check the toast property, and don't
144  * deconstruct "plain storage" array types --- this is because we don't
145  * want to show oidvector as oid[].
146  */
147  array_base_type = typeform->typelem;
148 
149  if (IsTrueArrayType(typeform) &&
150  typeform->typstorage != TYPSTORAGE_PLAIN)
151  {
152  /* Switch our attention to the array element type */
153  ReleaseSysCache(tuple);
154  tuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(array_base_type));
155  if (!HeapTupleIsValid(tuple))
156  {
157  if ((flags & FORMAT_TYPE_INVALID_AS_NULL) != 0)
158  return NULL;
159  else if ((flags & FORMAT_TYPE_ALLOW_INVALID) != 0)
160  return pstrdup("???[]");
161  else
162  elog(ERROR, "cache lookup failed for type %u", type_oid);
163  }
164  typeform = (Form_pg_type) GETSTRUCT(tuple);
165  type_oid = array_base_type;
166  is_array = true;
167  }
168  else
169  is_array = false;
170 
171  with_typemod = (flags & FORMAT_TYPE_TYPEMOD_GIVEN) != 0 && (typemod >= 0);
172 
173  /*
174  * See if we want to special-case the output for certain built-in types.
175  * Note that these special cases should all correspond to special
176  * productions in gram.y, to ensure that the type name will be taken as a
177  * system type, not a user type of the same name.
178  *
179  * If we do not provide a special-case output here, the type name will be
180  * handled the same way as a user type name --- in particular, it will be
181  * double-quoted if it matches any lexer keyword. This behavior is
182  * essential for some cases, such as types "bit" and "char".
183  */
184  buf = NULL; /* flag for no special case */
185 
186  switch (type_oid)
187  {
188  case BITOID:
189  if (with_typemod)
190  buf = printTypmod("bit", typemod, typeform->typmodout);
191  else if ((flags & FORMAT_TYPE_TYPEMOD_GIVEN) != 0)
192  {
193  /*
194  * bit with typmod -1 is not the same as BIT, which means
195  * BIT(1) per SQL spec. Report it as the quoted typename so
196  * that parser will not assign a bogus typmod.
197  */
198  }
199  else
200  buf = pstrdup("bit");
201  break;
202 
203  case BOOLOID:
204  buf = pstrdup("boolean");
205  break;
206 
207  case BPCHAROID:
208  if (with_typemod)
209  buf = printTypmod("character", typemod, typeform->typmodout);
210  else if ((flags & FORMAT_TYPE_TYPEMOD_GIVEN) != 0)
211  {
212  /*
213  * bpchar with typmod -1 is not the same as CHARACTER, which
214  * means CHARACTER(1) per SQL spec. Report it as bpchar so
215  * that parser will not assign a bogus typmod.
216  */
217  }
218  else
219  buf = pstrdup("character");
220  break;
221 
222  case FLOAT4OID:
223  buf = pstrdup("real");
224  break;
225 
226  case FLOAT8OID:
227  buf = pstrdup("double precision");
228  break;
229 
230  case INT2OID:
231  buf = pstrdup("smallint");
232  break;
233 
234  case INT4OID:
235  buf = pstrdup("integer");
236  break;
237 
238  case INT8OID:
239  buf = pstrdup("bigint");
240  break;
241 
242  case NUMERICOID:
243  if (with_typemod)
244  buf = printTypmod("numeric", typemod, typeform->typmodout);
245  else
246  buf = pstrdup("numeric");
247  break;
248 
249  case INTERVALOID:
250  if (with_typemod)
251  buf = printTypmod("interval", typemod, typeform->typmodout);
252  else
253  buf = pstrdup("interval");
254  break;
255 
256  case TIMEOID:
257  if (with_typemod)
258  buf = printTypmod("time", typemod, typeform->typmodout);
259  else
260  buf = pstrdup("time without time zone");
261  break;
262 
263  case TIMETZOID:
264  if (with_typemod)
265  buf = printTypmod("time", typemod, typeform->typmodout);
266  else
267  buf = pstrdup("time with time zone");
268  break;
269 
270  case TIMESTAMPOID:
271  if (with_typemod)
272  buf = printTypmod("timestamp", typemod, typeform->typmodout);
273  else
274  buf = pstrdup("timestamp without time zone");
275  break;
276 
277  case TIMESTAMPTZOID:
278  if (with_typemod)
279  buf = printTypmod("timestamp", typemod, typeform->typmodout);
280  else
281  buf = pstrdup("timestamp with time zone");
282  break;
283 
284  case VARBITOID:
285  if (with_typemod)
286  buf = printTypmod("bit varying", typemod, typeform->typmodout);
287  else
288  buf = pstrdup("bit varying");
289  break;
290 
291  case VARCHAROID:
292  if (with_typemod)
293  buf = printTypmod("character varying", typemod, typeform->typmodout);
294  else
295  buf = pstrdup("character varying");
296  break;
297 
298  case JSONOID:
299  buf = pstrdup("json");
300  break;
301  }
302 
303  if (buf == NULL)
304  {
305  /*
306  * Default handling: report the name as it appears in the catalog.
307  * Here, we must qualify the name if it is not visible in the search
308  * path or if caller requests it; and we must double-quote it if it's
309  * not a standard identifier or if it matches any keyword.
310  */
311  char *nspname;
312  char *typname;
313 
314  if ((flags & FORMAT_TYPE_FORCE_QUALIFY) == 0 &&
315  TypeIsVisible(type_oid))
316  nspname = NULL;
317  else
318  nspname = get_namespace_name_or_temp(typeform->typnamespace);
319 
320  typname = NameStr(typeform->typname);
321 
323 
324  if (with_typemod)
325  buf = printTypmod(buf, typemod, typeform->typmodout);
326  }
327 
328  if (is_array)
329  buf = psprintf("%s[]", buf);
330 
331  ReleaseSysCache(tuple);
332 
333  return buf;
334 }
335 
336 /*
337  * This version is for use within the backend in error messages, etc.
338  * One difference is that it will fail for an invalid type.
339  *
340  * The result is always a palloc'd string.
341  */
342 char *
344 {
345  return format_type_extended(type_oid, -1, 0);
346 }
347 
348 /*
349  * This version returns a name that is always qualified (unless it's one
350  * of the SQL-keyword type names, such as TIMESTAMP WITH TIME ZONE).
351  */
352 char *
354 {
355  return format_type_extended(type_oid, -1, FORMAT_TYPE_FORCE_QUALIFY);
356 }
357 
358 /*
359  * This version allows a nondefault typemod to be specified.
360  */
361 char *
363 {
364  return format_type_extended(type_oid, typemod, FORMAT_TYPE_TYPEMOD_GIVEN);
365 }
366 
367 /*
368  * Add typmod decoration to the basic type name
369  */
370 static char *
371 printTypmod(const char *typname, int32 typmod, Oid typmodout)
372 {
373  char *res;
374 
375  /* Shouldn't be called if typmod is -1 */
376  Assert(typmod >= 0);
377 
378  if (typmodout == InvalidOid)
379  {
380  /* Default behavior: just print the integer typmod with parens */
381  res = psprintf("%s(%d)", typname, (int) typmod);
382  }
383  else
384  {
385  /* Use the type-specific typmodout procedure */
386  char *tmstr;
387 
388  tmstr = DatumGetCString(OidFunctionCall1(typmodout,
389  Int32GetDatum(typmod)));
390  res = psprintf("%s%s", typname, tmstr);
391  }
392 
393  return res;
394 }
395 
396 
397 /*
398  * type_maximum_size --- determine maximum width of a variable-width column
399  *
400  * If the max width is indeterminate, return -1. In particular, we return
401  * -1 for any type not known to this routine. We assume the caller has
402  * already determined that the type is a variable-width type, so it's not
403  * necessary to look up the type's pg_type tuple here.
404  *
405  * This may appear unrelated to format_type(), but in fact the two routines
406  * share knowledge of the encoding of typmod for different types, so it's
407  * convenient to keep them together. (XXX now that most of this knowledge
408  * has been pushed out of format_type into the typmodout functions, it's
409  * interesting to wonder if it's worth trying to factor this code too...)
410  */
411 int32
412 type_maximum_size(Oid type_oid, int32 typemod)
413 {
414  if (typemod < 0)
415  return -1;
416 
417  switch (type_oid)
418  {
419  case BPCHAROID:
420  case VARCHAROID:
421  /* typemod includes varlena header */
422 
423  /* typemod is in characters not bytes */
424  return (typemod - VARHDRSZ) *
426  + VARHDRSZ;
427 
428  case NUMERICOID:
429  return numeric_maximum_size(typemod);
430 
431  case VARBITOID:
432  case BITOID:
433  /* typemod is the (max) number of bits */
434  return (typemod + (BITS_PER_BYTE - 1)) / BITS_PER_BYTE
435  + 2 * sizeof(int32);
436  }
437 
438  /* Unknown type, or unlimited-width type such as 'text' */
439  return -1;
440 }
441 
442 
443 /*
444  * oidvectortypes - converts a vector of type OIDs to "typname" list
445  */
446 Datum
448 {
449  oidvector *oidArray = (oidvector *) PG_GETARG_POINTER(0);
450  char *result;
451  int numargs = oidArray->dim1;
452  int num;
453  size_t total;
454  size_t left;
455 
456  total = 20 * numargs + 1;
457  result = palloc(total);
458  result[0] = '\0';
459  left = total - 1;
460 
461  for (num = 0; num < numargs; num++)
462  {
463  char *typename = format_type_extended(oidArray->values[num], -1,
465  size_t slen = strlen(typename);
466 
467  if (left < (slen + 2))
468  {
469  total += slen + 2;
470  result = repalloc(result, total);
471  left += slen + 2;
472  }
473 
474  if (num > 0)
475  {
476  strcat(result, ", ");
477  left -= 2;
478  }
479  strcat(result, typename);
480  left -= slen;
481  }
482 
484 }
int32 numeric_maximum_size(int32 typmod)
Definition: numeric.c:872
#define FORMAT_TYPE_ALLOW_INVALID
Definition: builtins.h:113
#define FORMAT_TYPE_INVALID_AS_NULL
Definition: builtins.h:115
#define FORMAT_TYPE_TYPEMOD_GIVEN
Definition: builtins.h:112
#define FORMAT_TYPE_FORCE_QUALIFY
Definition: builtins.h:114
#define NameStr(name)
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uint16 bits16
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signed int int32
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Definition: c.h:627
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Definition: elog.h:218
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Definition: fmgr.h:275
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Definition: format_type.c:353
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Definition: format_type.c:412
char * format_type_extended(Oid type_oid, int32 typemod, bits16 flags)
Definition: format_type.c:112
char * format_type_with_typemod(Oid type_oid, int32 typemod)
Definition: format_type.c:362
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Definition: format_type.c:60
Datum oidvectortypes(PG_FUNCTION_ARGS)
Definition: format_type.c:447
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Definition: format_type.c:343
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Definition: format_type.c:371
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Definition: htup.h:78
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Definition: htup_details.h:649
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static char * buf
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Definition: postgres.h:551
#define Int32GetDatum(X)
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unsigned int Oid
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@ TYPEOID
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