1/*-------------------------------------------------------------------------
2 *
3 * pg_collation.c
4 * routines to support manipulation of the pg_collation relation
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/catalog/pg_collation.c
12 *
13 *-------------------------------------------------------------------------
14 */
15#include "postgres.h"
16
17#include "access/genam.h"
18#include "access/htup_details.h"
19#include "access/sysattr.h"
20#include "access/table.h"
21#include "catalog/catalog.h"
22#include "catalog/dependency.h"
23#include "catalog/indexing.h"
24#include "catalog/objectaccess.h"
25#include "catalog/pg_collation.h"
26#include "catalog/pg_namespace.h"
27#include "mb/pg_wchar.h"
28#include "utils/builtins.h"
29#include "utils/fmgroids.h"
30#include "utils/pg_locale.h"
31#include "utils/rel.h"
32#include "utils/syscache.h"
33
34
35/*
36 * CollationCreate
37 *
38 * Add a new tuple to pg_collation.
39 *
40 * if_not_exists: if true, don't fail on duplicate name, just print a notice
41 * and return InvalidOid.
42 * quiet: if true, don't fail on duplicate name, just silently return
43 * InvalidOid (overrides if_not_exists).
44 */
45Oid
46CollationCreate(const char *collname, Oid collnamespace,
47 Oid collowner,
48 char collprovider,
49 bool collisdeterministic,
50 int32 collencoding,
51 const char *collcollate, const char *collctype,
52 const char *collversion,
53 bool if_not_exists,
54 bool quiet)
55{
56 Relation rel;
57 TupleDesc tupDesc;
58 HeapTuple tup;
59 Datum values[Natts_pg_collation];
60 bool nulls[Natts_pg_collation];
61 NameData name_name,
62 name_collate,
63 name_ctype;
64 Oid oid;
65 ObjectAddress myself,
66 referenced;
67
68 AssertArg(collname);
69 AssertArg(collnamespace);
70 AssertArg(collowner);
71 AssertArg(collcollate);
72 AssertArg(collctype);
73
74 /*
75 * Make sure there is no existing collation of same name & encoding.
76 *
77 * This would be caught by the unique index anyway; we're just giving a
78 * friendlier error message. The unique index provides a backstop against
79 * race conditions.
80 */
81 if (SearchSysCacheExists3(COLLNAMEENCNSP,
82 PointerGetDatum(collname),
83 Int32GetDatum(collencoding),
84 ObjectIdGetDatum(collnamespace)))
85 {
86 if (quiet)
87 return InvalidOid;
88 else if (if_not_exists)
89 {
90 ereport(NOTICE,
91 (errcode(ERRCODE_DUPLICATE_OBJECT),
92 collencoding == -1
93 ? errmsg("collation \"%s\" already exists, skipping",
94 collname)
95 : errmsg("collation \"%s\" for encoding \"%s\" already exists, skipping",
96 collname, pg_encoding_to_char(collencoding))));
97 return InvalidOid;
98 }
99 else
100 ereport(ERROR,
101 (errcode(ERRCODE_DUPLICATE_OBJECT),
102 collencoding == -1
103 ? errmsg("collation \"%s\" already exists",
104 collname)
105 : errmsg("collation \"%s\" for encoding \"%s\" already exists",
106 collname, pg_encoding_to_char(collencoding))));
107 }
108
109 /* open pg_collation; see below about the lock level */
110 rel = table_open(CollationRelationId, ShareRowExclusiveLock);
111
112 /*
113 * Also forbid a specific-encoding collation shadowing an any-encoding
114 * collation, or an any-encoding collation being shadowed (see
115 * get_collation_name()). This test is not backed up by the unique index,
116 * so we take a ShareRowExclusiveLock earlier, to protect against
117 * concurrent changes fooling this check.
118 */
119 if ((collencoding == -1 &&
120 SearchSysCacheExists3(COLLNAMEENCNSP,
121 PointerGetDatum(collname),
122 Int32GetDatum(GetDatabaseEncoding()),
123 ObjectIdGetDatum(collnamespace))) ||
124 (collencoding != -1 &&
125 SearchSysCacheExists3(COLLNAMEENCNSP,
126 PointerGetDatum(collname),
127 Int32GetDatum(-1),
128 ObjectIdGetDatum(collnamespace))))
129 {
130 if (quiet)
131 {
132 table_close(rel, NoLock);
133 return InvalidOid;
134 }
135 else if (if_not_exists)
136 {
137 table_close(rel, NoLock);
138 ereport(NOTICE,
139 (errcode(ERRCODE_DUPLICATE_OBJECT),
140 errmsg("collation \"%s\" already exists, skipping",
141 collname)));
142 return InvalidOid;
143 }
144 else
145 ereport(ERROR,
146 (errcode(ERRCODE_DUPLICATE_OBJECT),
147 errmsg("collation \"%s\" already exists",
148 collname)));
149 }
150
151 tupDesc = RelationGetDescr(rel);
152
153 /* form a tuple */
154 memset(nulls, 0, sizeof(nulls));
155
156 namestrcpy(&name_name, collname);
157 oid = GetNewOidWithIndex(rel, CollationOidIndexId,
158 Anum_pg_collation_oid);
159 values[Anum_pg_collation_oid - 1] = ObjectIdGetDatum(oid);
160 values[Anum_pg_collation_collname - 1] = NameGetDatum(&name_name);
161 values[Anum_pg_collation_collnamespace - 1] = ObjectIdGetDatum(collnamespace);
162 values[Anum_pg_collation_collowner - 1] = ObjectIdGetDatum(collowner);
163 values[Anum_pg_collation_collprovider - 1] = CharGetDatum(collprovider);
164 values[Anum_pg_collation_collisdeterministic - 1] = BoolGetDatum(collisdeterministic);
165 values[Anum_pg_collation_collencoding - 1] = Int32GetDatum(collencoding);
166 namestrcpy(&name_collate, collcollate);
167 values[Anum_pg_collation_collcollate - 1] = NameGetDatum(&name_collate);
168 namestrcpy(&name_ctype, collctype);
169 values[Anum_pg_collation_collctype - 1] = NameGetDatum(&name_ctype);
170 if (collversion)
171 values[Anum_pg_collation_collversion - 1] = CStringGetTextDatum(collversion);
172 else
173 nulls[Anum_pg_collation_collversion - 1] = true;
174
175 tup = heap_form_tuple(tupDesc, values, nulls);
176
177 /* insert a new tuple */
178 CatalogTupleInsert(rel, tup);
179 Assert(OidIsValid(oid));
180
181 /* set up dependencies for the new collation */
182 myself.classId = CollationRelationId;
183 myself.objectId = oid;
184 myself.objectSubId = 0;
185
186 /* create dependency on namespace */
187 referenced.classId = NamespaceRelationId;
188 referenced.objectId = collnamespace;
189 referenced.objectSubId = 0;
190 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
191
192 /* create dependency on owner */
193 recordDependencyOnOwner(CollationRelationId, oid, collowner);
194
195 /* dependency on extension */
196 recordDependencyOnCurrentExtension(&myself, false);
197
198 /* Post creation hook for new collation */
199 InvokeObjectPostCreateHook(CollationRelationId, oid, 0);
200
201 heap_freetuple(tup);
202 table_close(rel, NoLock);
203
204 return oid;
205}
206
207/*
208 * RemoveCollationById
209 *
210 * Remove a tuple from pg_collation by Oid. This function is solely
211 * called inside catalog/dependency.c
212 */
213void
214RemoveCollationById(Oid collationOid)
215{
216 Relation rel;
217 ScanKeyData scanKeyData;
218 SysScanDesc scandesc;
219 HeapTuple tuple;
220
221 rel = table_open(CollationRelationId, RowExclusiveLock);
222
223 ScanKeyInit(&scanKeyData,
224 Anum_pg_collation_oid,
225 BTEqualStrategyNumber, F_OIDEQ,
226 ObjectIdGetDatum(collationOid));
227
228 scandesc = systable_beginscan(rel, CollationOidIndexId, true,
229 NULL, 1, &scanKeyData);
230
231 tuple = systable_getnext(scandesc);
232
233 if (HeapTupleIsValid(tuple))
234 CatalogTupleDelete(rel, &tuple->t_self);
235 else
236 elog(ERROR, "could not find tuple for collation %u", collationOid);
237
238 systable_endscan(scandesc);
239
240 table_close(rel, RowExclusiveLock);
241}
242