Redesigns code with callbacks

src/backend/distributed/commands/non_main_db_distribute_object_ops.c

@@ -177,6 +177,15 @@ static void MarkObjectDistributedGloballyOnMainDbs(
 	MarkDistributedGloballyParams *markDistributedParams);
 static void UnmarkObjectsDistributedOnLocalMainDb(List *unmarkDistributedParamsList);
 
+const NonMainDbDistributeObjectOps * HandleCreateRoleStmt(Node *parsetree);
+const NonMainDbDistributeObjectOps * HandleDropRoleStmt(Node *parsetree);
+const NonMainDbDistributeObjectOps * HandleAlterRoleStmt(Node *parsetree);
+const NonMainDbDistributeObjectOps * HandleGrantRoleStmt(Node *parsetree);
+const NonMainDbDistributeObjectOps * HandleCreatedbStmt(Node *parsetree);
+const NonMainDbDistributeObjectOps * HandleDropdbStmt(Node *parsetree);
+const NonMainDbDistributeObjectOps * HandleGrantStmt(Node *parsetree);
+const NonMainDbDistributeObjectOps * HandleSecLabelStmt(Node *parsetree);
+
 
 /*
  * RunPreprocessNonMainDBCommand runs the necessary commands for a query, in main
@@ -265,38 +274,37 @@ RunPostprocessNonMainDBCommand(Node *parsetree)
 }
 
 
-/*
- * GetNonMainDbDistributeObjectOps returns the NonMainDbDistributeObjectOps for given
- * command if it's node-wide object management command that's supported from non-main
- * databases.
- */
 const NonMainDbDistributeObjectOps *
-GetNonMainDbDistributeObjectOps(Node *parsetree)
+HandleCreateRoleStmt(Node *parsetree)
 {
-	switch (nodeTag(parsetree))
-	{
-		case T_CreateRoleStmt:
-		{
 	return &Any_CreateRole;
-		}
+}
 
-		case T_DropRoleStmt:
+
-		{
+const NonMainDbDistributeObjectOps *
+HandleDropRoleStmt(Node *parsetree)
+{
 	return &Any_DropRole;
-		}
+}
 
-		case T_AlterRoleStmt:
+
-		{
+const NonMainDbDistributeObjectOps *
+HandleAlterRoleStmt(Node *parsetree)
+{
 	return &Any_AlterRole;
-		}
+}
 
-		case T_GrantRoleStmt:
+
-		{
+const NonMainDbDistributeObjectOps *
+HandleGrantRoleStmt(Node *parsetree)
+{
 	return &Any_GrantRole;
-		}
+}
 
-		case T_CreatedbStmt:
+
-		{
+const NonMainDbDistributeObjectOps *
+HandleCreatedbStmt(Node *parsetree)
+{
 	CreatedbStmt *stmt = castNode(CreatedbStmt, parsetree);
 
 	/*
@@ -310,10 +318,12 @@ GetNonMainDbDistributeObjectOps(Node *parsetree)
 	}
 
 	return NULL;
-		}
+}
 
-		case T_DropdbStmt:
+
-		{
+const NonMainDbDistributeObjectOps *
+HandleDropdbStmt(Node *parsetree)
+{
 	DropdbStmt *stmt = castNode(DropdbStmt, parsetree);
 
 	/*
@@ -327,10 +337,12 @@ GetNonMainDbDistributeObjectOps(Node *parsetree)
 	}
 
 	return NULL;
-		}
+}
 
-		case T_GrantStmt:
+
-		{
+const NonMainDbDistributeObjectOps *
+HandleGrantStmt(Node *parsetree)
+{
 	GrantStmt *stmt = castNode(GrantStmt, parsetree);
 
 	switch (stmt->objtype)
@@ -343,10 +355,12 @@ GetNonMainDbDistributeObjectOps(Node *parsetree)
 		default:
 			return NULL;
 	}
-		}
+}
 
-		case T_SecLabelStmt:
+
-		{
+const NonMainDbDistributeObjectOps *
+HandleSecLabelStmt(Node *parsetree)
+{
 	SecLabelStmt *stmt = castNode(SecLabelStmt, parsetree);
 
 	switch (stmt->objtype)
@@ -359,11 +373,47 @@ GetNonMainDbDistributeObjectOps(Node *parsetree)
 		default:
 			return NULL;
 	}
+}
+
+
+typedef const NonMainDbDistributeObjectOps *(*HandlerFunc)(Node *);
+
+static const struct
+{
+	NodeTag tag;
+	HandlerFunc handler;
+}
+handlers[] = {
+	{ T_CreateRoleStmt, HandleCreateRoleStmt },
+	{ T_DropRoleStmt, HandleDropRoleStmt },
+	{ T_AlterRoleStmt, HandleAlterRoleStmt },
+	{ T_GrantRoleStmt, HandleGrantRoleStmt },
+	{ T_CreatedbStmt, HandleCreatedbStmt },
+	{ T_DropdbStmt, HandleDropdbStmt },
+	{ T_GrantStmt, HandleGrantStmt },
+	{ T_SecLabelStmt, HandleSecLabelStmt },
+};
+
+
+/*
+ * GetNonMainDbDistributeObjectOps returns the NonMainDbDistributeObjectOps for given
+ * command if it's node-wide object management command that's supported from non-main
+ * databases.
+ */
+const NonMainDbDistributeObjectOps *
+GetNonMainDbDistributeObjectOps(Node *parsetree)
+{
+	NodeTag tag = nodeTag(parsetree);
+
+	for (int i = 0; i < sizeof(handlers) / sizeof(handlers[0]); i++)
+	{
+		if (handlers[i].tag == tag)
+		{
+			return handlers[i].handler(parsetree);
+		}
 	}
 
-		default:
 	return NULL;
-	}
 }