minio/internal/s3select/sql/utils.go

135 lines
3.6 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package sql
import (
"fmt"
"strings"
)
// String functions
// String - returns the JSONPath representation
func (e *JSONPath) String() string {
if len(e.pathString) == 0 {
parts := make([]string, len(e.PathExpr)+1)
parts[0] = e.BaseKey.String()
for i, pe := range e.PathExpr {
parts[i+1] = pe.String()
}
e.pathString = strings.Join(parts, "")
}
return e.pathString
}
// StripTableAlias removes a table alias from the path. The result is also
// cached for repeated lookups during SQL query evaluation.
func (e *JSONPath) StripTableAlias(tableAlias string) []*JSONPathElement {
if e.strippedTableAlias == tableAlias {
return e.strippedPathExpr
}
hasTableAlias := e.BaseKey.String() == tableAlias || strings.EqualFold(e.BaseKey.String(), baseTableName)
var pathExpr []*JSONPathElement
if hasTableAlias {
pathExpr = e.PathExpr
} else {
pathExpr = make([]*JSONPathElement, len(e.PathExpr)+1)
pathExpr[0] = &JSONPathElement{Key: &ObjectKey{ID: e.BaseKey}}
copy(pathExpr[1:], e.PathExpr)
}
e.strippedTableAlias = tableAlias
e.strippedPathExpr = pathExpr
return e.strippedPathExpr
}
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 ""
}
// String 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 := jpath.String()
if idx := strings.LastIndex(ps, "."); idx >= 0 {
// Get last part of path string.
ps = ps[idx+1:]
}
return ps, 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
}