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openGauss-server/src/gausskernel/optimizer/commands/comment.cpp

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/* -------------------------------------------------------------------------
*
* comment.cpp
*
* PostgreSQL object comments utility code.
*
* Portions Copyright (c) 2020 Huawei Technologies Co.,Ltd.
* Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 2010-2012 Postgres-XC Development Group
*
* IDENTIFICATION
* src/gausskernel/optimizer/commands/comment.cpp
*
* -------------------------------------------------------------------------
*/
#include "postgres.h"
#include "knl/knl_variable.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/tableam.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "catalog/objectaddress.h"
#include "catalog/pg_description.h"
#include "catalog/pg_object.h"
#include "catalog/pg_shdescription.h"
#include "commands/comment.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/rel_gs.h"
#include "utils/snapmgr.h"
/*
* @Description: check whether it's a share object.
* @in objtype : the type of the object.
* @return : return true if it's a share object like databases, tablespaces, roles or users.
*/
static bool CheckShareObject(ObjectType objtype)
{
if (objtype == OBJECT_DATABASE || objtype == OBJECT_TABLESPACE || objtype == OBJECT_ROLE || objtype == OBJECT_USER)
return true;
else
return false;
}
static AclResult CheckObjectCommentPrivilege(const CommentStmt* stmt, Oid objectId, const Relation relation)
{
AclResult aclresult = ACLCHECK_NO_PRIV;
switch (stmt->objtype) {
case OBJECT_SEQUENCE:
case OBJECT_TABLE:
case OBJECT_VIEW:
case OBJECT_MATVIEW:
case OBJECT_FOREIGN_TABLE:
aclresult = pg_class_aclcheck(objectId, GetUserId(), ACL_COMMENT);
break;
case OBJECT_INDEX:
aclresult = pg_class_aclcheck(IndexGetRelation(objectId, false), GetUserId(), ACL_INDEX);
break;
case OBJECT_COLUMN:
if (relation != NULL) {
Oid rel_id = RelationGetRelid(relation);
aclresult = pg_class_aclcheck(rel_id, GetUserId(), ACL_COMMENT);
if (aclresult != ACLCHECK_OK) {
char* attname = strVal(lfirst(list_tail(stmt->objname)));
AttrNumber attnum = get_attnum(rel_id, attname);
aclresult = pg_attribute_aclcheck(rel_id, attnum, GetUserId(), ACL_COMMENT);
}
}
break;
case OBJECT_TYPE:
aclresult = pg_type_aclcheck(objectId, GetUserId(), ACL_COMMENT);
break;
case OBJECT_DATABASE:
aclresult = pg_database_aclcheck(objectId, GetUserId(), ACL_COMMENT);
break;
case OBJECT_FUNCTION:
aclresult = pg_proc_aclcheck(objectId, GetUserId(), ACL_COMMENT);
break;
case OBJECT_SCHEMA:
aclresult = pg_namespace_aclcheck(objectId, GetUserId(), ACL_COMMENT);
break;
case OBJECT_FOREIGN_SERVER:
aclresult = pg_foreign_server_aclcheck(objectId, GetUserId(), ACL_COMMENT);
break;
case OBJECT_TABLESPACE:
aclresult = pg_tablespace_aclcheck(objectId, GetUserId(), ACL_COMMENT);
break;
default:
aclresult = ACLCHECK_NO_PRIV;
break;
}
return aclresult;
}
/*
* CommentObject --
*
* This routine is used to add the associated comment into
* pg_description for the object specified by the given SQL command.
*/
void CommentObject(CommentStmt* stmt)
{
ObjectAddress address;
Relation relation;
/*
* When loading a dump, we may see a COMMENT ON DATABASE for the old name
* of the database. Erroring out would prevent pg_restore from completing
* (which is really pg_restore's fault, but for now we will work around
* the problem here). Consensus is that the best fix is to treat wrong
* database name as a WARNING not an ERROR; hence, the following special
* case. (If the length of stmt->objname is not 1, get_object_address
* will throw an error below; that's OK.)
*/
if (stmt->objtype == OBJECT_DATABASE && list_length(stmt->objname) == 1) {
char* database = strVal(linitial(stmt->objname));
if (!OidIsValid(get_database_oid(database, true))) {
ereport(WARNING, (errcode(ERRCODE_UNDEFINED_DATABASE), errmsg("database \"%s\" does not exist", database)));
return;
}
}
/*
* Translate the parser representation that identifies this object into an
* ObjectAddress. get_object_address() will throw an error if the object
* does not exist, and will also acquire a lock on the target to guard
* against concurrent DROP operations.
*/
address =
get_object_address(stmt->objtype, stmt->objname, stmt->objargs, &relation, ShareUpdateExclusiveLock, false);
/* Require ownership or comment privilege of the target object. */
AclResult aclresult = CheckObjectCommentPrivilege(stmt, address.objectId, relation);
if (aclresult != ACLCHECK_OK) {
check_object_ownership(GetUserId(), stmt->objtype, address, stmt->objname, stmt->objargs, relation);
}
/* Perform other integrity checks as needed. */
switch (stmt->objtype) {
case OBJECT_COLUMN:
/*
* Allow comments only on columns of tables, views, materialized
* views, composite types, and foreign tables (which are the only
* relkinds for which pg_dump will dump per-column comments). In
* particular we wish to disallow comments on index columns,
* because the naming of an index's columns may change across PG
* versions, so dumping per-column comments could create reload
* failures.
*/
if (relation != NULL) {
if (relation->rd_rel->relkind != RELKIND_RELATION &&
relation->rd_rel->relkind != RELKIND_VIEW &&
relation->rd_rel->relkind != RELKIND_CONTQUERY &&
relation->rd_rel->relkind != RELKIND_MATVIEW &&
relation->rd_rel->relkind != RELKIND_COMPOSITE_TYPE &&
relation->rd_rel->relkind != RELKIND_STREAM &&
relation->rd_rel->relkind != RELKIND_FOREIGN_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table, view, composite type, or foreign table",
RelationGetRelationName(relation))));
}
break;
default:
break;
}
/*
* Databases, tablespaces, roles and users are cluster-wide objects, so any
* comments on those objects are recorded in the shared pg_shdescription
* catalog. Comments on all other objects are recorded in pg_description.
*/
if (CheckShareObject(stmt->objtype))
CreateSharedComments(address.objectId, address.classId, stmt->comment);
else
CreateComments(address.objectId, address.classId, address.objectSubId, stmt->comment);
/* Recode time of comment object. */
recordCommentObjectTime(address, relation, stmt->objtype);
/*
* If get_object_address() opened the relation for us, we close it to keep
* the reference count correct - but we retain any locks acquired by
* get_object_address() until commit time, to guard against concurrent
* activity.
*/
if (relation != NULL)
relation_close(relation, NoLock);
}
/*
* CreateComments --
*
* Create a comment for the specified object descriptor. Inserts a new
* pg_description tuple, or replaces an existing one with the same key.
*
* If the comment given is null or an empty string, instead delete any
* existing comment for the specified key.
*/
void CreateComments(Oid oid, Oid classoid, int32 subid, const char* comment)
{
Relation description;
ScanKeyData skey[3];
SysScanDesc sd;
HeapTuple oldtuple;
HeapTuple newtuple = NULL;
Datum values[Natts_pg_description];
bool nulls[Natts_pg_description];
bool replaces[Natts_pg_description];
int i;
/* Reduce empty-string to NULL case */
if (comment != NULL && strlen(comment) == 0)
comment = NULL;
/* Prepare to form or update a tuple, if necessary */
if (comment != NULL) {
for (i = 0; i < Natts_pg_description; i++) {
nulls[i] = false;
replaces[i] = true;
}
values[Anum_pg_description_objoid - 1] = ObjectIdGetDatum(oid);
values[Anum_pg_description_classoid - 1] = ObjectIdGetDatum(classoid);
values[Anum_pg_description_objsubid - 1] = Int32GetDatum(subid);
values[Anum_pg_description_description - 1] = CStringGetTextDatum(comment);
}
/* Use the index to search for a matching old tuple */
ScanKeyInit(&skey[0], Anum_pg_description_objoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(oid));
ScanKeyInit(&skey[1], Anum_pg_description_classoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(classoid));
ScanKeyInit(&skey[2], Anum_pg_description_objsubid, BTEqualStrategyNumber, F_INT4EQ, Int32GetDatum(subid));
description = heap_open(DescriptionRelationId, RowExclusiveLock);
sd = systable_beginscan(description, DescriptionObjIndexId, true, NULL, 3, skey);
if ((oldtuple = systable_getnext(sd)) != NULL) {
/* Found the old tuple, so delete or update it */
if (comment == NULL) {
simple_heap_delete(description, &oldtuple->t_self);
} else {
newtuple = (HeapTuple) tableam_tops_modify_tuple(oldtuple, RelationGetDescr(description), values, nulls, replaces);
simple_heap_update(description, &oldtuple->t_self, newtuple);
}
} /* Assume there can be only one match */
systable_endscan(sd);
/* If we didn't find an old tuple, insert a new one */
if (newtuple == NULL && comment != NULL) {
newtuple = heap_form_tuple(RelationGetDescr(description), values, nulls);
(void)simple_heap_insert(description, newtuple);
}
/* Update indexes, if necessary */
if (newtuple != NULL) {
CatalogUpdateIndexes(description, newtuple);
tableam_tops_free_tuple(newtuple);
}
/* Done */
heap_close(description, NoLock);
}
/*
* CreateSharedComments --
*
* Create a comment for the specified shared object descriptor. Inserts a
* new pg_shdescription tuple, or replaces an existing one with the same key.
*
* If the comment given is null or an empty string, instead delete any
* existing comment for the specified key.
*/
void CreateSharedComments(Oid oid, Oid classoid, const char* comment)
{
Relation shdescription;
ScanKeyData skey[2];
SysScanDesc sd;
HeapTuple oldtuple;
HeapTuple newtuple = NULL;
Datum values[Natts_pg_shdescription];
bool nulls[Natts_pg_shdescription];
bool replaces[Natts_pg_shdescription];
int i;
/* Reduce empty-string to NULL case */
if (comment != NULL && strlen(comment) == 0)
comment = NULL;
/* Prepare to form or update a tuple, if necessary */
if (comment != NULL) {
for (i = 0; i < Natts_pg_shdescription; i++) {
nulls[i] = false;
replaces[i] = true;
}
values[Anum_pg_shdescription_objoid - 1] = ObjectIdGetDatum(oid);
values[Anum_pg_shdescription_classoid - 1] = ObjectIdGetDatum(classoid);
values[Anum_pg_shdescription_description - 1] = CStringGetTextDatum(comment);
}
/* Use the index to search for a matching old tuple */
ScanKeyInit(&skey[0], Anum_pg_shdescription_objoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(oid));
ScanKeyInit(&skey[1], Anum_pg_shdescription_classoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(classoid));
shdescription = heap_open(SharedDescriptionRelationId, RowExclusiveLock);
sd = systable_beginscan(shdescription, SharedDescriptionObjIndexId, true, NULL, 2, skey);
if ((oldtuple = systable_getnext(sd)) != NULL) {
/* Found the old tuple, so delete or update it */
if (comment == NULL)
simple_heap_delete(shdescription, &oldtuple->t_self);
else {
newtuple = (HeapTuple) tableam_tops_modify_tuple(oldtuple, RelationGetDescr(shdescription), values, nulls, replaces);
simple_heap_update(shdescription, &oldtuple->t_self, newtuple);
}
} /* Assume there can be only one match */
systable_endscan(sd);
/* If we didn't find an old tuple, insert a new one */
if (newtuple == NULL && comment != NULL) {
newtuple = heap_form_tuple(RelationGetDescr(shdescription), values, nulls);
(void)simple_heap_insert(shdescription, newtuple);
}
/* Update indexes, if necessary */
if (newtuple != NULL) {
CatalogUpdateIndexes(shdescription, newtuple);
tableam_tops_free_tuple(newtuple);
}
/* Done */
heap_close(shdescription, NoLock);
}
/*
* DeleteComments -- remove comments for an object
*
* If subid is nonzero then only comments matching it will be removed.
* If subid is zero, all comments matching the oid/classoid will be removed
* (this corresponds to deleting a whole object).
*/
void DeleteComments(Oid oid, Oid classoid, int32 subid)
{
Relation description;
ScanKeyData skey[3];
int nkeys;
SysScanDesc sd;
HeapTuple oldtuple;
/* Use the index to search for all matching old tuples */
ScanKeyInit(&skey[0], Anum_pg_description_objoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(oid));
ScanKeyInit(&skey[1], Anum_pg_description_classoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(classoid));
if (subid != 0) {
ScanKeyInit(&skey[2], Anum_pg_description_objsubid, BTEqualStrategyNumber, F_INT4EQ, Int32GetDatum(subid));
nkeys = 3;
} else
nkeys = 2;
description = heap_open(DescriptionRelationId, RowExclusiveLock);
sd = systable_beginscan(description, DescriptionObjIndexId, true, NULL, nkeys, skey);
while ((oldtuple = systable_getnext(sd)) != NULL)
simple_heap_delete(description, &oldtuple->t_self);
/* Done */
systable_endscan(sd);
heap_close(description, RowExclusiveLock);
}
/*
* DeleteSharedComments -- remove comments for a shared object
*/
void DeleteSharedComments(Oid oid, Oid classoid)
{
Relation shdescription;
ScanKeyData skey[2];
SysScanDesc sd;
HeapTuple oldtuple;
/* Use the index to search for all matching old tuples */
ScanKeyInit(&skey[0], Anum_pg_shdescription_objoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(oid));
ScanKeyInit(&skey[1], Anum_pg_shdescription_classoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(classoid));
shdescription = heap_open(SharedDescriptionRelationId, RowExclusiveLock);
sd = systable_beginscan(shdescription, SharedDescriptionObjIndexId, true, NULL, 2, skey);
while ((oldtuple = systable_getnext(sd)) != NULL)
simple_heap_delete(shdescription, &oldtuple->t_self);
/* Done */
systable_endscan(sd);
heap_close(shdescription, RowExclusiveLock);
}
/*
* GetComment -- get the comment for an object, or null if not found.
*/
char* GetComment(Oid oid, Oid classoid, int32 subid)
{
Relation description;
ScanKeyData skey[3];
SysScanDesc sd;
TupleDesc tupdesc;
HeapTuple tuple;
char* comment = NULL;
/* Use the index to search for a matching old tuple */
ScanKeyInit(&skey[0], Anum_pg_description_objoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(oid));
ScanKeyInit(&skey[1], Anum_pg_description_classoid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(classoid));
ScanKeyInit(&skey[2], Anum_pg_description_objsubid, BTEqualStrategyNumber, F_INT4EQ, Int32GetDatum(subid));
description = heap_open(DescriptionRelationId, AccessShareLock);
tupdesc = RelationGetDescr(description);
sd = systable_beginscan(description, DescriptionObjIndexId, true, NULL, 3, skey);
comment = NULL;
if ((tuple = systable_getnext(sd)) != NULL) {
Datum value;
bool isnull = false;
/* Found the tuple, get description field */
value = tableam_tops_tuple_getattr(tuple, Anum_pg_description_description, tupdesc, &isnull);
if (!isnull)
comment = TextDatumGetCString(value);
} /* Assume there can be only one match */
systable_endscan(sd);
/* Done */
heap_close(description, AccessShareLock);
return comment;
}
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