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domains.c
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1 /*-------------------------------------------------------------------------
2  *
3  * domains.c
4  * I/O functions for domain types.
5  *
6  * The output functions for a domain type are just the same ones provided
7  * by its underlying base type. The input functions, however, must be
8  * prepared to apply any constraints defined by the type. So, we create
9  * special input functions that invoke the base type's input function
10  * and then check the constraints.
11  *
12  * The overhead required for constraint checking can be high, since examining
13  * the catalogs to discover the constraints for a given domain is not cheap.
14  * We have three mechanisms for minimizing this cost:
15  * 1. We rely on the typcache to keep up-to-date copies of the constraints.
16  * 2. In a nest of domains, we flatten the checking of all the levels
17  * into just one operation (the typcache does this for us).
18  * 3. If there are CHECK constraints, we cache a standalone ExprContext
19  * to evaluate them in.
20  *
21  *
22  * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
23  * Portions Copyright (c) 1994, Regents of the University of California
24  *
25  *
26  * IDENTIFICATION
27  * src/backend/utils/adt/domains.c
28  *
29  *-------------------------------------------------------------------------
30  */
31 #include "postgres.h"
32 
33 #include "access/htup_details.h"
34 #include "catalog/pg_type.h"
35 #include "executor/executor.h"
36 #include "lib/stringinfo.h"
37 #include "utils/builtins.h"
38 #include "utils/expandeddatum.h"
39 #include "utils/lsyscache.h"
40 #include "utils/syscache.h"
41 #include "utils/typcache.h"
42 
43 
44 /*
45  * structure to cache state across multiple calls
46  */
47 typedef struct DomainIOData
48 {
50  /* Data needed to call base type's input function */
55  /* Reference to cached list of constraint items to check */
57  /* Context for evaluating CHECK constraints in */
59  /* Memory context this cache is in */
61 } DomainIOData;
62 
63 
64 /*
65  * domain_state_setup - initialize the cache for a new domain type.
66  *
67  * Note: we can't re-use the same cache struct for a new domain type,
68  * since there's no provision for releasing the DomainConstraintRef.
69  * If a call site needs to deal with a new domain type, we just leak
70  * the old struct for the duration of the query.
71  */
72 static DomainIOData *
73 domain_state_setup(Oid domainType, bool binary, MemoryContext mcxt)
74 {
75  DomainIOData *my_extra;
76  TypeCacheEntry *typentry;
77  Oid baseType;
78 
79  my_extra = (DomainIOData *) MemoryContextAlloc(mcxt, sizeof(DomainIOData));
80 
81  /*
82  * Verify that domainType represents a valid domain type. We need to be
83  * careful here because domain_in and domain_recv can be called from SQL,
84  * possibly with incorrect arguments. We use lookup_type_cache mainly
85  * because it will throw a clean user-facing error for a bad OID; but also
86  * it can cache the underlying base type info.
87  */
88  typentry = lookup_type_cache(domainType, TYPECACHE_DOMAIN_BASE_INFO);
89  if (typentry->typtype != TYPTYPE_DOMAIN)
90  ereport(ERROR,
91  (errcode(ERRCODE_DATATYPE_MISMATCH),
92  errmsg("type %s is not a domain",
93  format_type_be(domainType))));
94 
95  /* Find out the base type */
96  baseType = typentry->domainBaseType;
97  my_extra->typtypmod = typentry->domainBaseTypmod;
98 
99  /* Look up underlying I/O function */
100  if (binary)
101  getTypeBinaryInputInfo(baseType,
102  &my_extra->typiofunc,
103  &my_extra->typioparam);
104  else
105  getTypeInputInfo(baseType,
106  &my_extra->typiofunc,
107  &my_extra->typioparam);
108  fmgr_info_cxt(my_extra->typiofunc, &my_extra->proc, mcxt);
109 
110  /* Look up constraints for domain */
111  InitDomainConstraintRef(domainType, &my_extra->constraint_ref, mcxt, true);
112 
113  /* We don't make an ExprContext until needed */
114  my_extra->econtext = NULL;
115  my_extra->mcxt = mcxt;
116 
117  /* Mark cache valid */
118  my_extra->domain_type = domainType;
119 
120  return my_extra;
121 }
122 
123 /*
124  * domain_check_input - apply the cached checks.
125  *
126  * This is roughly similar to the handling of CoerceToDomain nodes in
127  * execExpr*.c, but we execute each constraint separately, rather than
128  * compiling them in-line within a larger expression.
129  */
130 static void
131 domain_check_input(Datum value, bool isnull, DomainIOData *my_extra)
132 {
133  ExprContext *econtext = my_extra->econtext;
134  ListCell *l;
135 
136  /* Make sure we have up-to-date constraints */
138 
139  foreach(l, my_extra->constraint_ref.constraints)
140  {
142 
143  switch (con->constrainttype)
144  {
146  if (isnull)
147  ereport(ERROR,
148  (errcode(ERRCODE_NOT_NULL_VIOLATION),
149  errmsg("domain %s does not allow null values",
150  format_type_be(my_extra->domain_type)),
151  errdatatype(my_extra->domain_type)));
152  break;
154  {
155  /* Make the econtext if we didn't already */
156  if (econtext == NULL)
157  {
158  MemoryContext oldcontext;
159 
160  oldcontext = MemoryContextSwitchTo(my_extra->mcxt);
161  econtext = CreateStandaloneExprContext();
162  MemoryContextSwitchTo(oldcontext);
163  my_extra->econtext = econtext;
164  }
165 
166  /*
167  * Set up value to be returned by CoerceToDomainValue
168  * nodes. Unlike in the generic expression case, this
169  * econtext couldn't be shared with anything else, so no
170  * need to save and restore fields. But we do need to
171  * protect the passed-in value against being changed by
172  * called functions. (It couldn't be a R/W expanded
173  * object for most uses, but that seems possible for
174  * domain_check().)
175  */
176  econtext->domainValue_datum =
177  MakeExpandedObjectReadOnly(value, isnull,
178  my_extra->constraint_ref.tcache->typlen);
179  econtext->domainValue_isNull = isnull;
180 
181  if (!ExecCheck(con->check_exprstate, econtext))
182  ereport(ERROR,
183  (errcode(ERRCODE_CHECK_VIOLATION),
184  errmsg("value for domain %s violates check constraint \"%s\"",
185  format_type_be(my_extra->domain_type),
186  con->name),
188  con->name)));
189  break;
190  }
191  default:
192  elog(ERROR, "unrecognized constraint type: %d",
193  (int) con->constrainttype);
194  break;
195  }
196  }
197 
198  /*
199  * Before exiting, call any shutdown callbacks and reset econtext's
200  * per-tuple memory. This avoids leaking non-memory resources, if
201  * anything in the expression(s) has any.
202  */
203  if (econtext)
204  ReScanExprContext(econtext);
205 }
206 
207 
208 /*
209  * domain_in - input routine for any domain type.
210  */
211 Datum
213 {
214  char *string;
215  Oid domainType;
216  DomainIOData *my_extra;
217  Datum value;
218 
219  /*
220  * Since domain_in is not strict, we have to check for null inputs. The
221  * typioparam argument should never be null in normal system usage, but it
222  * could be null in a manual invocation --- if so, just return null.
223  */
224  if (PG_ARGISNULL(0))
225  string = NULL;
226  else
227  string = PG_GETARG_CSTRING(0);
228  if (PG_ARGISNULL(1))
229  PG_RETURN_NULL();
230  domainType = PG_GETARG_OID(1);
231 
232  /*
233  * We arrange to look up the needed info just once per series of calls,
234  * assuming the domain type doesn't change underneath us (which really
235  * shouldn't happen, but cope if it does).
236  */
237  my_extra = (DomainIOData *) fcinfo->flinfo->fn_extra;
238  if (my_extra == NULL || my_extra->domain_type != domainType)
239  {
240  my_extra = domain_state_setup(domainType, false,
241  fcinfo->flinfo->fn_mcxt);
242  fcinfo->flinfo->fn_extra = (void *) my_extra;
243  }
244 
245  /*
246  * Invoke the base type's typinput procedure to convert the data.
247  */
248  value = InputFunctionCall(&my_extra->proc,
249  string,
250  my_extra->typioparam,
251  my_extra->typtypmod);
252 
253  /*
254  * Do the necessary checks to ensure it's a valid domain value.
255  */
256  domain_check_input(value, (string == NULL), my_extra);
257 
258  if (string == NULL)
259  PG_RETURN_NULL();
260  else
261  PG_RETURN_DATUM(value);
262 }
263 
264 /*
265  * domain_recv - binary input routine for any domain type.
266  */
267 Datum
269 {
270  StringInfo buf;
271  Oid domainType;
272  DomainIOData *my_extra;
273  Datum value;
274 
275  /*
276  * Since domain_recv is not strict, we have to check for null inputs. The
277  * typioparam argument should never be null in normal system usage, but it
278  * could be null in a manual invocation --- if so, just return null.
279  */
280  if (PG_ARGISNULL(0))
281  buf = NULL;
282  else
283  buf = (StringInfo) PG_GETARG_POINTER(0);
284  if (PG_ARGISNULL(1))
285  PG_RETURN_NULL();
286  domainType = PG_GETARG_OID(1);
287 
288  /*
289  * We arrange to look up the needed info just once per series of calls,
290  * assuming the domain type doesn't change underneath us (which really
291  * shouldn't happen, but cope if it does).
292  */
293  my_extra = (DomainIOData *) fcinfo->flinfo->fn_extra;
294  if (my_extra == NULL || my_extra->domain_type != domainType)
295  {
296  my_extra = domain_state_setup(domainType, true,
297  fcinfo->flinfo->fn_mcxt);
298  fcinfo->flinfo->fn_extra = (void *) my_extra;
299  }
300 
301  /*
302  * Invoke the base type's typreceive procedure to convert the data.
303  */
304  value = ReceiveFunctionCall(&my_extra->proc,
305  buf,
306  my_extra->typioparam,
307  my_extra->typtypmod);
308 
309  /*
310  * Do the necessary checks to ensure it's a valid domain value.
311  */
312  domain_check_input(value, (buf == NULL), my_extra);
313 
314  if (buf == NULL)
315  PG_RETURN_NULL();
316  else
317  PG_RETURN_DATUM(value);
318 }
319 
320 /*
321  * domain_check - check that a datum satisfies the constraints of a
322  * domain. extra and mcxt can be passed if they are available from,
323  * say, a FmgrInfo structure, or they can be NULL, in which case the
324  * setup is repeated for each call.
325  */
326 void
327 domain_check(Datum value, bool isnull, Oid domainType,
328  void **extra, MemoryContext mcxt)
329 {
330  DomainIOData *my_extra = NULL;
331 
332  if (mcxt == NULL)
333  mcxt = CurrentMemoryContext;
334 
335  /*
336  * We arrange to look up the needed info just once per series of calls,
337  * assuming the domain type doesn't change underneath us (which really
338  * shouldn't happen, but cope if it does).
339  */
340  if (extra)
341  my_extra = (DomainIOData *) *extra;
342  if (my_extra == NULL || my_extra->domain_type != domainType)
343  {
344  my_extra = domain_state_setup(domainType, true, mcxt);
345  if (extra)
346  *extra = (void *) my_extra;
347  }
348 
349  /*
350  * Do the necessary checks to ensure it's a valid domain value.
351  */
352  domain_check_input(value, isnull, my_extra);
353 }
354 
355 /*
356  * errdatatype --- stores schema_name and datatype_name of a datatype
357  * within the current errordata.
358  */
359 int
360 errdatatype(Oid datatypeOid)
361 {
362  HeapTuple tup;
363  Form_pg_type typtup;
364 
365  tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(datatypeOid));
366  if (!HeapTupleIsValid(tup))
367  elog(ERROR, "cache lookup failed for type %u", datatypeOid);
368  typtup = (Form_pg_type) GETSTRUCT(tup);
369 
371  get_namespace_name(typtup->typnamespace));
373 
374  ReleaseSysCache(tup);
375 
376  return 0; /* return value does not matter */
377 }
378 
379 /*
380  * errdomainconstraint --- stores schema_name, datatype_name and
381  * constraint_name of a domain-related constraint within the current errordata.
382  */
383 int
384 errdomainconstraint(Oid datatypeOid, const char *conname)
385 {
386  errdatatype(datatypeOid);
388 
389  return 0; /* return value does not matter */
390 }
ExprContext * CreateStandaloneExprContext(void)
Definition: execUtils.c:300
Definition: fmgr.h:56
#define GETSTRUCT(TUP)
Definition: htup_details.h:668
#define PG_DIAG_SCHEMA_NAME
Definition: postgres_ext.h:65
void UpdateDomainConstraintRef(DomainConstraintRef *ref)
Definition: typcache.c:1229
DomainConstraintType constrainttype
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StringInfoData * StringInfo
Definition: stringinfo.h:43
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:109
int errcode(int sqlerrcode)
Definition: elog.c:575
Datum domain_in(PG_FUNCTION_ARGS)
Definition: domains.c:212
Oid domain_type
Definition: domains.c:49
char * format_type_be(Oid type_oid)
Definition: format_type.c:328
#define PG_GETARG_POINTER(n)
Definition: fmgr.h:246
unsigned int Oid
Definition: postgres_ext.h:31
Datum domainValue_datum
Definition: execnodes.h:249
int16 typlen
Definition: typcache.h:37
FmgrInfo proc
Definition: domains.c:54
signed int int32
Definition: c.h:313
Oid domainBaseType
Definition: typcache.h:104
int32 typtypmod
Definition: domains.c:53
struct DomainIOData DomainIOData
Datum domain_recv(PG_FUNCTION_ARGS)
Definition: domains.c:268
#define ObjectIdGetDatum(X)
Definition: postgres.h:492
#define ERROR
Definition: elog.h:43
int errdomainconstraint(Oid datatypeOid, const char *conname)
Definition: domains.c:384
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Definition: domains.c:58
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Definition: lsyscache.c:3051
static char * buf
Definition: pg_test_fsync.c:67
#define PG_GETARG_OID(n)
Definition: fmgr.h:245
char string[11]
Definition: preproc-type.c:46
int32 domainBaseTypmod
Definition: typcache.h:105
#define MakeExpandedObjectReadOnly(d, isnull, typlen)
ExprState * check_exprstate
Definition: execnodes.h:879
MemoryContext CurrentMemoryContext
Definition: mcxt.c:38
void fmgr_info_cxt(Oid functionId, FmgrInfo *finfo, MemoryContext mcxt)
Definition: fmgr.c:134
void getTypeBinaryInputInfo(Oid type, Oid *typReceive, Oid *typIOParam)
Definition: lsyscache.c:2683
void getTypeInputInfo(Oid type, Oid *typInput, Oid *typIOParam)
Definition: lsyscache.c:2617
#define ereport(elevel, rest)
Definition: elog.h:122
#define TYPECACHE_DOMAIN_BASE_INFO
Definition: typcache.h:139
HeapTuple SearchSysCache1(int cacheId, Datum key1)
Definition: syscache.c:1112
bool domainValue_isNull
Definition: execnodes.h:251
Oid typiofunc
Definition: domains.c:51
uintptr_t Datum
Definition: postgres.h:367
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Definition: syscache.c:1160
#define PG_RETURN_DATUM(x)
Definition: fmgr.h:318
int errdatatype(Oid datatypeOid)
Definition: domains.c:360
#define PG_DIAG_DATATYPE_NAME
Definition: postgres_ext.h:68
static struct @131 value
void domain_check(Datum value, bool isnull, Oid domainType, void **extra, MemoryContext mcxt)
Definition: domains.c:327
#define PG_DIAG_CONSTRAINT_NAME
Definition: postgres_ext.h:69
Datum InputFunctionCall(FmgrInfo *flinfo, char *str, Oid typioparam, int32 typmod)
Definition: fmgr.c:1709
TypeCacheEntry * lookup_type_cache(Oid type_id, int flags)
Definition: typcache.c:321
DomainConstraintRef constraint_ref
Definition: domains.c:56
char typtype
Definition: typcache.h:41
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Definition: domains.c:52
#define PG_ARGISNULL(n)
Definition: fmgr.h:179
#define HeapTupleIsValid(tuple)
Definition: htup.h:78
#define lfirst(lc)
Definition: pg_list.h:106
void InitDomainConstraintRef(Oid type_id, DomainConstraintRef *ref, MemoryContext refctx, bool need_exprstate)
Definition: typcache.c:1191
TypeCacheEntry * tcache
Definition: typcache.h:157
FormData_pg_type * Form_pg_type
Definition: pg_type.h:247
void ReScanExprContext(ExprContext *econtext)
Definition: execUtils.c:386
static DomainIOData * domain_state_setup(Oid domainType, bool binary, MemoryContext mcxt)
Definition: domains.c:73
MemoryContext mcxt
Definition: domains.c:60
int errmsg(const char *fmt,...)
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Definition: mcxt.c:771
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#define PG_GETARG_CSTRING(n)
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#define PG_FUNCTION_ARGS
Definition: fmgr.h:163
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Definition: elog.h:219
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Definition: elog.c:1191
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Definition: fmgr.h:310
static void domain_check_input(Datum value, bool isnull, DomainIOData *my_extra)
Definition: domains.c:131