1 /*-------------------------------------------------------------------------
2 *
3 * pg_conversion.c
4 * routines to support manipulation of the pg_conversion relation
5 *
6 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/catalog/pg_conversion.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres.h"
16
17 #include "access/heapam.h"
18 #include "access/htup_details.h"
19 #include "access/sysattr.h"
20 #include "access/tableam.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_conversion.h"
26 #include "catalog/pg_namespace.h"
27 #include "catalog/pg_proc.h"
28 #include "mb/pg_wchar.h"
29 #include "utils/builtins.h"
30 #include "utils/catcache.h"
31 #include "utils/fmgroids.h"
32 #include "utils/rel.h"
33 #include "utils/syscache.h"
34
35 /*
36 * ConversionCreate
37 *
38 * Add a new tuple to pg_conversion.
39 */
40 ObjectAddress
ConversionCreate(const char * conname,Oid connamespace,Oid conowner,int32 conforencoding,int32 contoencoding,Oid conproc,bool def)41 ConversionCreate(const char *conname, Oid connamespace,
42 Oid conowner,
43 int32 conforencoding, int32 contoencoding,
44 Oid conproc, bool def)
45 {
46 int i;
47 Relation rel;
48 TupleDesc tupDesc;
49 HeapTuple tup;
50 Oid oid;
51 bool nulls[Natts_pg_conversion];
52 Datum values[Natts_pg_conversion];
53 NameData cname;
54 ObjectAddress myself,
55 referenced;
56
57 /* sanity checks */
58 if (!conname)
59 elog(ERROR, "no conversion name supplied");
60
61 /* make sure there is no existing conversion of same name */
62 if (SearchSysCacheExists2(CONNAMENSP,
63 PointerGetDatum(conname),
64 ObjectIdGetDatum(connamespace)))
65 ereport(ERROR,
66 (errcode(ERRCODE_DUPLICATE_OBJECT),
67 errmsg("conversion \"%s\" already exists", conname)));
68
69 if (def)
70 {
71 /*
72 * make sure there is no existing default <for encoding><to encoding>
73 * pair in this name space
74 */
75 if (FindDefaultConversion(connamespace,
76 conforencoding,
77 contoencoding))
78 ereport(ERROR,
79 (errcode(ERRCODE_DUPLICATE_OBJECT),
80 errmsg("default conversion for %s to %s already exists",
81 pg_encoding_to_char(conforencoding),
82 pg_encoding_to_char(contoencoding))));
83 }
84
85 /* open pg_conversion */
86 rel = table_open(ConversionRelationId, RowExclusiveLock);
87 tupDesc = rel->rd_att;
88
89 /* initialize nulls and values */
90 for (i = 0; i < Natts_pg_conversion; i++)
91 {
92 nulls[i] = false;
93 values[i] = (Datum) NULL;
94 }
95
96 /* form a tuple */
97 namestrcpy(&cname, conname);
98 oid = GetNewOidWithIndex(rel, ConversionOidIndexId,
99 Anum_pg_conversion_oid);
100 values[Anum_pg_conversion_oid - 1] = ObjectIdGetDatum(oid);
101 values[Anum_pg_conversion_conname - 1] = NameGetDatum(&cname);
102 values[Anum_pg_conversion_connamespace - 1] = ObjectIdGetDatum(connamespace);
103 values[Anum_pg_conversion_conowner - 1] = ObjectIdGetDatum(conowner);
104 values[Anum_pg_conversion_conforencoding - 1] = Int32GetDatum(conforencoding);
105 values[Anum_pg_conversion_contoencoding - 1] = Int32GetDatum(contoencoding);
106 values[Anum_pg_conversion_conproc - 1] = ObjectIdGetDatum(conproc);
107 values[Anum_pg_conversion_condefault - 1] = BoolGetDatum(def);
108
109 tup = heap_form_tuple(tupDesc, values, nulls);
110
111 /* insert a new tuple */
112 CatalogTupleInsert(rel, tup);
113
114 myself.classId = ConversionRelationId;
115 myself.objectId = oid;
116 myself.objectSubId = 0;
117
118 /* create dependency on conversion procedure */
119 referenced.classId = ProcedureRelationId;
120 referenced.objectId = conproc;
121 referenced.objectSubId = 0;
122 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
123
124 /* create dependency on namespace */
125 referenced.classId = NamespaceRelationId;
126 referenced.objectId = connamespace;
127 referenced.objectSubId = 0;
128 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
129
130 /* create dependency on owner */
131 recordDependencyOnOwner(ConversionRelationId, oid, conowner);
132
133 /* dependency on extension */
134 recordDependencyOnCurrentExtension(&myself, false);
135
136 /* Post creation hook for new conversion */
137 InvokeObjectPostCreateHook(ConversionRelationId, oid, 0);
138
139 heap_freetuple(tup);
140 table_close(rel, RowExclusiveLock);
141
142 return myself;
143 }
144
145 /*
146 * FindDefaultConversion
147 *
148 * Find "default" conversion proc by for_encoding and to_encoding in the
149 * given namespace.
150 *
151 * If found, returns the procedure's oid, otherwise InvalidOid. Note that
152 * you get the procedure's OID not the conversion's OID!
153 */
154 Oid
FindDefaultConversion(Oid name_space,int32 for_encoding,int32 to_encoding)155 FindDefaultConversion(Oid name_space, int32 for_encoding, int32 to_encoding)
156 {
157 CatCList *catlist;
158 HeapTuple tuple;
159 Form_pg_conversion body;
160 Oid proc = InvalidOid;
161 int i;
162
163 catlist = SearchSysCacheList3(CONDEFAULT,
164 ObjectIdGetDatum(name_space),
165 Int32GetDatum(for_encoding),
166 Int32GetDatum(to_encoding));
167
168 for (i = 0; i < catlist->n_members; i++)
169 {
170 tuple = &catlist->members[i]->tuple;
171 body = (Form_pg_conversion) GETSTRUCT(tuple);
172 if (body->condefault)
173 {
174 proc = body->conproc;
175 break;
176 }
177 }
178 ReleaseSysCacheList(catlist);
179 return proc;
180 }
181