minio/pkg/s3select/sql/utils.go

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/*
* MinIO Cloud Storage, (C) 2019 MinIO, 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 sql
import (
"fmt"
"strings"
)
// String functions
// String - returns the JSONPath representation
func (e *JSONPath) String() string {
parts := make([]string, len(e.PathExpr)+1)
parts[0] = e.BaseKey.String()
for i, pe := range e.PathExpr {
parts[i+1] = pe.String()
}
return strings.Join(parts, "")
}
func (e *JSONPathElement) String() string {
switch {
case e.Key != nil:
return e.Key.String()
case e.Index != nil:
return fmt.Sprintf("[%d]", *e.Index)
case e.ObjectWildcard:
return ".*"
case e.ArrayWildcard:
return "[*]"
}
return ""
}
// Removes double quotes in quoted identifiers
func (i *Identifier) String() string {
if i.Unquoted != nil {
return *i.Unquoted
}
return string(*i.Quoted)
}
func (o *ObjectKey) String() string {
if o.Lit != nil {
return fmt.Sprintf("['%s']", string(*o.Lit))
}
return fmt.Sprintf(".%s", o.ID.String())
}
func (o *ObjectKey) keyString() string {
if o.Lit != nil {
return string(*o.Lit)
}
return o.ID.String()
}
// getLastKeypathComponent checks if the given expression is a path
// expression, and if so extracts the last dot separated component of
// the path. Otherwise it returns false.
func getLastKeypathComponent(e *Expression) (string, bool) {
if len(e.And) > 1 ||
len(e.And[0].Condition) > 1 ||
e.And[0].Condition[0].Not != nil ||
e.And[0].Condition[0].Operand.ConditionRHS != nil {
return "", false
}
operand := e.And[0].Condition[0].Operand.Operand
if operand.Right != nil ||
operand.Left.Right != nil ||
operand.Left.Left.Negated != nil ||
operand.Left.Left.Primary.JPathExpr == nil {
return "", false
}
// Check if path expression ends in a key
jpath := operand.Left.Left.Primary.JPathExpr
n := len(jpath.PathExpr)
if n > 0 && jpath.PathExpr[n-1].Key == nil {
return "", false
}
ps := strings.Split(jpath.String(), ".")
return ps[len(ps)-1], true
}
// HasKeypath returns if the from clause has a key path -
// e.g. S3object[*].id
func (from *TableExpression) HasKeypath() bool {
return len(from.Table.PathExpr) > 1
}