chore: import upstream snapshot with attribution

server/ast/table_name.go

@@ -0,0 +1,51 @@
+// Copyright 2023 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ast
+
+import (
+	"strings"
+
+	vitess "github.com/dolthub/vitess/go/vt/sqlparser"
+
+	"github.com/dolthub/doltgresql/postgres/parser/sem/tree"
+)
+
+// nodeTableName handles *tree.TableName nodes.
+func nodeTableName(ctx *Context, node *tree.TableName) (vitess.TableName, error) {
+	if node == nil {
+		return vitess.TableName{}, nil
+	}
+	var dbName, schemaName vitess.TableIdent
+	if node.ExplicitCatalog {
+		dbName = vitess.NewTableIdent(string(node.CatalogName))
+	}
+	if node.ExplicitSchema {
+		schemaName = vitess.NewTableIdent(string(node.SchemaName))
+	}
+	// for the information_schema schema, we treat it as a database name to make queries against it work with the engine
+	// TODO: this is a hack, we need to handle information_schema differently for doltgres, and as a true schema in each db
+	if strings.EqualFold(schemaName.String(), "information_schema") {
+		return vitess.TableName{
+			Name:        vitess.NewTableIdent(string(node.ObjectName)),
+			DbQualifier: schemaName,
+		}, nil
+	} else {
+		return vitess.TableName{
+			Name:            vitess.NewTableIdent(string(node.ObjectName)),
+			DbQualifier:     dbName,
+			SchemaQualifier: schemaName,
+		}, nil
+	}
+}