Allow new values to be added to an existing enum type.

After much expenditure of effort, we've got this to the point where the
performance penalty is pretty minimal in typical cases.

Andrew Dunstan, reviewed by Brendan Jurd, Dean Rasheed, and Tom Lane

1 files changed, 64 insertions, 9 deletions

diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 46b156e09a3..220be9b443b 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -84,7 +84,8 @@ static Oid	findTypeTypmodinFunction(List *procname);
 static Oid	findTypeTypmodoutFunction(List *procname);
 static Oid	findTypeAnalyzeFunction(List *procname, Oid typeOid);
 static List *get_rels_with_domain(Oid domainOid, LOCKMODE lockmode);
-static void checkDomainOwner(HeapTuple tup, TypeName *typename);
+static void checkDomainOwner(HeapTuple tup);
+static void checkEnumOwner(HeapTuple tup);
 static char *domainAddConstraint(Oid domainOid, Oid domainNamespace,
 					Oid baseTypeOid,
 					int typMod, Constraint *constr,
@@ -1150,7 +1151,7 @@ DefineEnum(CreateEnumStmt *stmt)
 				   false);		/* Type NOT NULL */
 
 	/* Enter the enum's values into pg_enum */
-	EnumValuesCreate(enumTypeOid, stmt->vals, InvalidOid);
+	EnumValuesCreate(enumTypeOid, stmt->vals);
 
 	/*
 	 * Create the array type that goes with it.
@@ -1191,6 +1192,60 @@ DefineEnum(CreateEnumStmt *stmt)
 	pfree(enumArrayName);
 }
 
+/*
+ * AlterEnum
+ *		Adds a new label to an existing enum.
+ */
+void
+AlterEnum(AlterEnumStmt *stmt)
+{
+	Oid			enum_type_oid;
+	TypeName   *typename;
+	HeapTuple	tup;
+
+	/* Make a TypeName so we can use standard type lookup machinery */
+	typename = makeTypeNameFromNameList(stmt->typeName);
+	enum_type_oid = typenameTypeId(NULL, typename, NULL);
+
+	tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(enum_type_oid));
+	if (!HeapTupleIsValid(tup))
+		elog(ERROR, "cache lookup failed for type %u", enum_type_oid);
+
+	/* Check it's an enum and check user has permission to ALTER the enum */
+	checkEnumOwner(tup);
+
+	/* Add the new label */
+	AddEnumLabel(enum_type_oid, stmt->newVal,
+				 stmt->newValNeighbor, stmt->newValIsAfter);
+
+	ReleaseSysCache(tup);
+}
+
+
+/*
+ * checkEnumOwner
+ *
+ * Check that the type is actually an enum and that the current user
+ * has permission to do ALTER TYPE on it.  Throw an error if not.
+ */
+static void
+checkEnumOwner(HeapTuple tup)
+{
+	Form_pg_type typTup = (Form_pg_type) GETSTRUCT(tup);
+
+	/* Check that this is actually an enum */
+	if (typTup->typtype != TYPTYPE_ENUM)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("%s is not an enum",
+						format_type_be(HeapTupleGetOid(tup)))));
+
+	/* Permission check: must own type */
+	if (!pg_type_ownercheck(HeapTupleGetOid(tup), GetUserId()))
+		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TYPE,
+					   format_type_be(HeapTupleGetOid(tup)));
+}
+
 
 /*
  * Find suitable I/O functions for a type.
@@ -1576,7 +1631,7 @@ AlterDomainDefault(List *names, Node *defaultRaw)
 	typTup = (Form_pg_type) GETSTRUCT(tup);
 
 	/* Check it's a domain and check user has permission for ALTER DOMAIN */
-	checkDomainOwner(tup, typename);
+	checkDomainOwner(tup);
 
 	/* Setup new tuple */
 	MemSet(new_record, (Datum) 0, sizeof(new_record));
@@ -1702,7 +1757,7 @@ AlterDomainNotNull(List *names, bool notNull)
 	typTup = (Form_pg_type) GETSTRUCT(tup);
 
 	/* Check it's a domain and check user has permission for ALTER DOMAIN */
-	checkDomainOwner(tup, typename);
+	checkDomainOwner(tup);
 
 	/* Is the domain already set to the desired constraint? */
 	if (typTup->typnotnull == notNull)
@@ -1801,7 +1856,7 @@ AlterDomainDropConstraint(List *names, const char *constrName,
 		elog(ERROR, "cache lookup failed for type %u", domainoid);
 
 	/* Check it's a domain and check user has permission for ALTER DOMAIN */
-	checkDomainOwner(tup, typename);
+	checkDomainOwner(tup);
 
 	/* Grab an appropriate lock on the pg_constraint relation */
 	conrel = heap_open(ConstraintRelationId, RowExclusiveLock);
@@ -1875,7 +1930,7 @@ AlterDomainAddConstraint(List *names, Node *newConstraint)
 	typTup = (Form_pg_type) GETSTRUCT(tup);
 
 	/* Check it's a domain and check user has permission for ALTER DOMAIN */
-	checkDomainOwner(tup, typename);
+	checkDomainOwner(tup);
 
 	if (!IsA(newConstraint, Constraint))
 		elog(ERROR, "unrecognized node type: %d",
@@ -2187,7 +2242,7 @@ get_rels_with_domain(Oid domainOid, LOCKMODE lockmode)
  * has permission to do ALTER DOMAIN on it.  Throw an error if not.
  */
 static void
-checkDomainOwner(HeapTuple tup, TypeName *typename)
+checkDomainOwner(HeapTuple tup)
 {
 	Form_pg_type typTup = (Form_pg_type) GETSTRUCT(tup);
 
@@ -2195,8 +2250,8 @@ checkDomainOwner(HeapTuple tup, TypeName *typename)
 	if (typTup->typtype != TYPTYPE_DOMAIN)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a domain",
-						TypeNameToString(typename))));
+				 errmsg("%s is not a domain",
+						format_type_be(HeapTupleGetOid(tup)))));
 
 	/* Permission check: must own type */
 	if (!pg_type_ownercheck(HeapTupleGetOid(tup), GetUserId()))