S3 Select API Support for CSV (#6127)

Add support for trivial where clause cases

vendor/github.com/xwb1989/sqlparser/encodable.go

@@ -0,0 +1,99 @@
+/*
+Copyright 2017 Google 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 sqlparser
+
+import (
+	"bytes"
+
+	"github.com/xwb1989/sqlparser/dependency/sqltypes"
+)
+
+// This file contains types that are 'Encodable'.
+
+// Encodable defines the interface for types that can
+// be custom-encoded into SQL.
+type Encodable interface {
+	EncodeSQL(buf *bytes.Buffer)
+}
+
+// InsertValues is a custom SQL encoder for the values of
+// an insert statement.
+type InsertValues [][]sqltypes.Value
+
+// EncodeSQL performs the SQL encoding for InsertValues.
+func (iv InsertValues) EncodeSQL(buf *bytes.Buffer) {
+	for i, rows := range iv {
+		if i != 0 {
+			buf.WriteString(", ")
+		}
+		buf.WriteByte('(')
+		for j, bv := range rows {
+			if j != 0 {
+				buf.WriteString(", ")
+			}
+			bv.EncodeSQL(buf)
+		}
+		buf.WriteByte(')')
+	}
+}
+
+// TupleEqualityList is for generating equality constraints
+// for tables that have composite primary keys.
+type TupleEqualityList struct {
+	Columns []ColIdent
+	Rows    [][]sqltypes.Value
+}
+
+// EncodeSQL generates the where clause constraints for the tuple
+// equality.
+func (tpl *TupleEqualityList) EncodeSQL(buf *bytes.Buffer) {
+	if len(tpl.Columns) == 1 {
+		tpl.encodeAsIn(buf)
+		return
+	}
+	tpl.encodeAsEquality(buf)
+}
+
+func (tpl *TupleEqualityList) encodeAsIn(buf *bytes.Buffer) {
+	Append(buf, tpl.Columns[0])
+	buf.WriteString(" in (")
+	for i, r := range tpl.Rows {
+		if i != 0 {
+			buf.WriteString(", ")
+		}
+		r[0].EncodeSQL(buf)
+	}
+	buf.WriteByte(')')
+}
+
+func (tpl *TupleEqualityList) encodeAsEquality(buf *bytes.Buffer) {
+	for i, r := range tpl.Rows {
+		if i != 0 {
+			buf.WriteString(" or ")
+		}
+		buf.WriteString("(")
+		for j, c := range tpl.Columns {
+			if j != 0 {
+				buf.WriteString(" and ")
+			}
+			Append(buf, c)
+			buf.WriteString(" = ")
+			r[j].EncodeSQL(buf)
+		}
+		buf.WriteByte(')')
+	}
+}