1 /*-------------------------------------------------------------------------
2 *
3 * pg_conversion.c
4 * routines to support manipulation of the pg_conversion relation
5 *
6 * Portions Copyright (c) 1996-2017, 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 "catalog/dependency.h"
21 #include "catalog/indexing.h"
22 #include "catalog/objectaccess.h"
23 #include "catalog/pg_conversion.h"
24 #include "catalog/pg_conversion_fn.h"
25 #include "catalog/pg_namespace.h"
26 #include "catalog/pg_proc.h"
27 #include "mb/pg_wchar.h"
28 #include "utils/builtins.h"
29 #include "utils/catcache.h"
30 #include "utils/fmgroids.h"
31 #include "utils/rel.h"
32 #include "utils/syscache.h"
33 #include "utils/tqual.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 bool nulls[Natts_pg_conversion];
51 Datum values[Natts_pg_conversion];
52 NameData cname;
53 ObjectAddress myself,
54 referenced;
55
56 /* sanity checks */
57 if (!conname)
58 elog(ERROR, "no conversion name supplied");
59
60 /* make sure there is no existing conversion of same name */
61 if (SearchSysCacheExists2(CONNAMENSP,
62 PointerGetDatum(conname),
63 ObjectIdGetDatum(connamespace)))
64 ereport(ERROR,
65 (errcode(ERRCODE_DUPLICATE_OBJECT),
66 errmsg("conversion \"%s\" already exists", conname)));
67
68 if (def)
69 {
70 /*
71 * make sure there is no existing default <for encoding><to encoding>
72 * pair in this name space
73 */
74 if (FindDefaultConversion(connamespace,
75 conforencoding,
76 contoencoding))
77 ereport(ERROR,
78 (errcode(ERRCODE_DUPLICATE_OBJECT),
79 errmsg("default conversion for %s to %s already exists",
80 pg_encoding_to_char(conforencoding),
81 pg_encoding_to_char(contoencoding))));
82 }
83
84 /* open pg_conversion */
85 rel = heap_open(ConversionRelationId, RowExclusiveLock);
86 tupDesc = rel->rd_att;
87
88 /* initialize nulls and values */
89 for (i = 0; i < Natts_pg_conversion; i++)
90 {
91 nulls[i] = false;
92 values[i] = (Datum) NULL;
93 }
94
95 /* form a tuple */
96 namestrcpy(&cname, conname);
97 values[Anum_pg_conversion_conname - 1] = NameGetDatum(&cname);
98 values[Anum_pg_conversion_connamespace - 1] = ObjectIdGetDatum(connamespace);
99 values[Anum_pg_conversion_conowner - 1] = ObjectIdGetDatum(conowner);
100 values[Anum_pg_conversion_conforencoding - 1] = Int32GetDatum(conforencoding);
101 values[Anum_pg_conversion_contoencoding - 1] = Int32GetDatum(contoencoding);
102 values[Anum_pg_conversion_conproc - 1] = ObjectIdGetDatum(conproc);
103 values[Anum_pg_conversion_condefault - 1] = BoolGetDatum(def);
104
105 tup = heap_form_tuple(tupDesc, values, nulls);
106
107 /* insert a new tuple */
108 CatalogTupleInsert(rel, tup);
109
110 myself.classId = ConversionRelationId;
111 myself.objectId = HeapTupleGetOid(tup);
112 myself.objectSubId = 0;
113
114 /* create dependency on conversion procedure */
115 referenced.classId = ProcedureRelationId;
116 referenced.objectId = conproc;
117 referenced.objectSubId = 0;
118 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
119
120 /* create dependency on namespace */
121 referenced.classId = NamespaceRelationId;
122 referenced.objectId = connamespace;
123 referenced.objectSubId = 0;
124 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
125
126 /* create dependency on owner */
127 recordDependencyOnOwner(ConversionRelationId, HeapTupleGetOid(tup),
128 conowner);
129
130 /* dependency on extension */
131 recordDependencyOnCurrentExtension(&myself, false);
132
133 /* Post creation hook for new conversion */
134 InvokeObjectPostCreateHook(ConversionRelationId, HeapTupleGetOid(tup), 0);
135
136 heap_freetuple(tup);
137 heap_close(rel, RowExclusiveLock);
138
139 return myself;
140 }
141
142 /*
143 * RemoveConversionById
144 *
145 * Remove a tuple from pg_conversion by Oid. This function is solely
146 * called inside catalog/dependency.c
147 */
148 void
RemoveConversionById(Oid conversionOid)149 RemoveConversionById(Oid conversionOid)
150 {
151 Relation rel;
152 HeapTuple tuple;
153 HeapScanDesc scan;
154 ScanKeyData scanKeyData;
155
156 ScanKeyInit(&scanKeyData,
157 ObjectIdAttributeNumber,
158 BTEqualStrategyNumber, F_OIDEQ,
159 ObjectIdGetDatum(conversionOid));
160
161 /* open pg_conversion */
162 rel = heap_open(ConversionRelationId, RowExclusiveLock);
163
164 scan = heap_beginscan_catalog(rel, 1, &scanKeyData);
165
166 /* search for the target tuple */
167 if (HeapTupleIsValid(tuple = heap_getnext(scan, ForwardScanDirection)))
168 CatalogTupleDelete(rel, &tuple->t_self);
169 else
170 elog(ERROR, "could not find tuple for conversion %u", conversionOid);
171 heap_endscan(scan);
172 heap_close(rel, RowExclusiveLock);
173 }
174
175 /*
176 * FindDefaultConversion
177 *
178 * Find "default" conversion proc by for_encoding and to_encoding in the
179 * given namespace.
180 *
181 * If found, returns the procedure's oid, otherwise InvalidOid. Note that
182 * you get the procedure's OID not the conversion's OID!
183 */
184 Oid
FindDefaultConversion(Oid name_space,int32 for_encoding,int32 to_encoding)185 FindDefaultConversion(Oid name_space, int32 for_encoding, int32 to_encoding)
186 {
187 CatCList *catlist;
188 HeapTuple tuple;
189 Form_pg_conversion body;
190 Oid proc = InvalidOid;
191 int i;
192
193 catlist = SearchSysCacheList3(CONDEFAULT,
194 ObjectIdGetDatum(name_space),
195 Int32GetDatum(for_encoding),
196 Int32GetDatum(to_encoding));
197
198 for (i = 0; i < catlist->n_members; i++)
199 {
200 tuple = &catlist->members[i]->tuple;
201 body = (Form_pg_conversion) GETSTRUCT(tuple);
202 if (body->condefault)
203 {
204 proc = body->conproc;
205 break;
206 }
207 }
208 ReleaseSysCacheList(catlist);
209 return proc;
210 }
211