Files
tidb/expression/regexp.go
2015-09-23 10:18:56 +08:00

133 lines
3.0 KiB
Go

// Copyright 2013 The ql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSES/QL-LICENSE file.
// Copyright 2015 PingCAP, 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package expression
import (
"fmt"
"regexp"
"github.com/juju/errors"
"github.com/pingcap/tidb/context"
)
var (
_ Expression = (*PatternRegexp)(nil)
)
// PatternRegexp is the pattern expression for pattern match.
// TODO: refactor later.
type PatternRegexp struct {
// Expr is the expression to be checked.
Expr Expression
// Pattern is the expression for pattern.
Pattern Expression
// Re is the compiled regexp.
Re *regexp.Regexp
// Sexpr is the string for Expr expression.
Sexpr *string
// Not is true, the expression is "not rlike",
Not bool
}
// Clone implements the Expression Clone interface.
func (p *PatternRegexp) Clone() Expression {
expr := p.Expr.Clone()
pattern := p.Pattern.Clone()
return &PatternRegexp{
Expr: expr,
Pattern: pattern,
Re: p.Re,
Sexpr: p.Sexpr,
Not: p.Not,
}
}
// IsStatic implements the Expression IsStatic interface.
func (p *PatternRegexp) IsStatic() bool {
return p.Expr.IsStatic() && p.Pattern.IsStatic()
}
// String implements the Expression String interface.
func (p *PatternRegexp) String() string {
return fmt.Sprintf("%s RLIKE %s", p.Expr, p.Pattern)
}
// Eval implements the Expression Eval interface.
func (p *PatternRegexp) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error) {
var sexpr string
var ok bool
switch {
case p.Sexpr != nil:
sexpr = *p.Sexpr
default:
expr, err := p.Expr.Eval(ctx, args)
if err != nil {
return nil, err
}
if expr == nil {
return nil, nil
}
sexpr, ok = expr.(string)
if !ok {
return nil, errors.Errorf("non-string Expression in LIKE: %v (Value of type %T)", expr, expr)
}
if p.Expr.IsStatic() {
p.Sexpr = new(string)
*p.Sexpr = sexpr
}
}
re := p.Re
if re == nil {
pattern, err := p.Pattern.Eval(ctx, args)
if err != nil {
return nil, err
}
if pattern == nil {
return nil, nil
}
spattern, ok := pattern.(string)
if !ok {
return nil, errors.Errorf("non-string pattern in LIKE: %v (Value of type %T)", pattern, pattern)
}
if re, err = regexp.Compile(spattern); err != nil {
return nil, err
}
if p.Pattern.IsStatic() {
p.Re = re
}
}
match := re.MatchString(sexpr)
if p.Not {
return !match, nil
}
return match, nil
}
// Accept implements Expression Accept interface.
func (p *PatternRegexp) Accept(v Visitor) (Expression, error) {
return v.VisitPatternRegexp(p)
}