Files
tidb/xapi/xeval/eval.go
2016-07-08 19:59:13 +08:00

585 lines
14 KiB
Go

// Copyright 2016 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 xeval
import (
"sort"
"strings"
"time"
"github.com/juju/errors"
"github.com/pingcap/tidb/mysql"
"github.com/pingcap/tidb/terror"
"github.com/pingcap/tidb/util/codec"
"github.com/pingcap/tidb/util/types"
"github.com/pingcap/tipb/go-tipb"
)
// Error instances.
var (
ErrInvalid = terror.ClassXEval.New(CodeInvalid, "invalid operation")
)
// Error codes.
const (
CodeInvalid = 3
)
const (
compareResultNull = -2
)
// Evaluator evaluates tipb.Expr.
type Evaluator struct {
Row map[int64]types.Datum // column values.
valueLists map[*tipb.Expr]*decodedValueList
}
type decodedValueList struct {
values []types.Datum
hasNull bool
}
// Eval evaluates expr to a Datum.
func (e *Evaluator) Eval(expr *tipb.Expr) (types.Datum, error) {
switch expr.GetTp() {
case tipb.ExprType_Null:
return types.Datum{}, nil
case tipb.ExprType_Int64:
return e.evalInt(expr.Val)
case tipb.ExprType_Uint64:
return e.evalUint(expr.Val)
case tipb.ExprType_String:
return e.evalString(expr.Val)
case tipb.ExprType_Bytes:
return types.NewBytesDatum(expr.Val), nil
case tipb.ExprType_Float32:
return e.evalFloat(expr.Val, true)
case tipb.ExprType_Float64:
return e.evalFloat(expr.Val, false)
case tipb.ExprType_MysqlDecimal:
return e.evalDecimal(expr.Val)
case tipb.ExprType_MysqlDuration:
return e.evalDuration(expr.Val)
case tipb.ExprType_ColumnRef:
return e.evalColumnRef(expr.Val)
case tipb.ExprType_LT:
return e.evalLT(expr)
case tipb.ExprType_LE:
return e.evalLE(expr)
case tipb.ExprType_EQ:
return e.evalEQ(expr)
case tipb.ExprType_NE:
return e.evalNE(expr)
case tipb.ExprType_GE:
return e.evalGE(expr)
case tipb.ExprType_GT:
return e.evalGT(expr)
case tipb.ExprType_NullEQ:
return e.evalNullEQ(expr)
case tipb.ExprType_And:
return e.evalAnd(expr)
case tipb.ExprType_Or:
return e.evalOr(expr)
case tipb.ExprType_Like:
return e.evalLike(expr)
case tipb.ExprType_Not:
return e.evalNot(expr)
case tipb.ExprType_In:
return e.evalIn(expr)
case tipb.ExprType_Plus, tipb.ExprType_Div:
return e.evalArithmetic(expr)
}
return types.Datum{}, nil
}
func (e *Evaluator) evalColumnRef(val []byte) (types.Datum, error) {
var d types.Datum
_, i, err := codec.DecodeInt(val)
if err != nil {
return d, errors.Trace(err)
}
d, ok := e.Row[i]
if !ok {
return d, ErrInvalid.Gen("column % x not found", val)
}
return d, nil
}
func (e *Evaluator) evalInt(val []byte) (types.Datum, error) {
var d types.Datum
_, i, err := codec.DecodeInt(val)
if err != nil {
return d, ErrInvalid.Gen("invalid int % x", val)
}
d.SetInt64(i)
return d, nil
}
func (e *Evaluator) evalUint(val []byte) (types.Datum, error) {
var d types.Datum
_, u, err := codec.DecodeUint(val)
if err != nil {
return d, ErrInvalid.Gen("invalid uint % x", val)
}
d.SetUint64(u)
return d, nil
}
func (e *Evaluator) evalString(val []byte) (types.Datum, error) {
var d types.Datum
d.SetBytesAsString(val)
return d, nil
}
func (e *Evaluator) evalFloat(val []byte, f32 bool) (types.Datum, error) {
var d types.Datum
_, f, err := codec.DecodeFloat(val)
if err != nil {
return d, ErrInvalid.Gen("invalid float % x", val)
}
if f32 {
d.SetFloat32(float32(f))
} else {
d.SetFloat64(f)
}
return d, nil
}
func (e *Evaluator) evalDecimal(val []byte) (types.Datum, error) {
var d types.Datum
_, dec, err := codec.DecodeDecimal(val)
if err != nil {
return d, ErrInvalid.Gen("invalid decimal % x", val)
}
d.SetMysqlDecimal(dec)
return d, nil
}
func (e *Evaluator) evalDuration(val []byte) (types.Datum, error) {
var d types.Datum
_, i, err := codec.DecodeInt(val)
if err != nil {
return d, ErrInvalid.Gen("invalid duration %d", i)
}
d.SetMysqlDuration(mysql.Duration{Duration: time.Duration(i), Fsp: mysql.MaxFsp})
return d, nil
}
func (e *Evaluator) evalLT(expr *tipb.Expr) (types.Datum, error) {
cmp, err := e.compareTwoChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if cmp == compareResultNull {
return types.Datum{}, nil
} else if cmp < 0 {
return types.NewIntDatum(1), nil
} else {
return types.NewIntDatum(0), nil
}
}
func (e *Evaluator) evalLE(expr *tipb.Expr) (types.Datum, error) {
cmp, err := e.compareTwoChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if cmp == compareResultNull {
return types.Datum{}, nil
} else if cmp <= 0 {
return types.NewIntDatum(1), nil
} else {
return types.NewIntDatum(0), nil
}
}
func (e *Evaluator) evalEQ(expr *tipb.Expr) (types.Datum, error) {
cmp, err := e.compareTwoChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if cmp == compareResultNull {
return types.Datum{}, nil
} else if cmp == 0 {
return types.NewIntDatum(1), nil
} else {
return types.NewIntDatum(0), nil
}
}
func (e *Evaluator) evalNE(expr *tipb.Expr) (types.Datum, error) {
cmp, err := e.compareTwoChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if cmp == compareResultNull {
return types.Datum{}, nil
} else if cmp != 0 {
return types.NewIntDatum(1), nil
} else {
return types.NewIntDatum(0), nil
}
}
func (e *Evaluator) evalGE(expr *tipb.Expr) (types.Datum, error) {
cmp, err := e.compareTwoChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if cmp == compareResultNull {
return types.Datum{}, nil
} else if cmp >= 0 {
return types.NewIntDatum(1), nil
} else {
return types.NewIntDatum(0), nil
}
}
func (e *Evaluator) evalGT(expr *tipb.Expr) (types.Datum, error) {
cmp, err := e.compareTwoChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if cmp == compareResultNull {
return types.Datum{}, nil
} else if cmp > 0 {
return types.NewIntDatum(1), nil
} else {
return types.NewIntDatum(0), nil
}
}
func (e *Evaluator) evalNullEQ(expr *tipb.Expr) (types.Datum, error) {
left, right, err := e.evalTwoChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
cmp, err := left.CompareDatum(right)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if cmp == 0 {
return types.NewIntDatum(1), nil
}
return types.NewIntDatum(0), nil
}
func (e *Evaluator) compareTwoChildren(expr *tipb.Expr) (int, error) {
left, right, err := e.evalTwoChildren(expr)
if err != nil {
return 0, errors.Trace(err)
}
if left.IsNull() || right.IsNull() {
return compareResultNull, nil
}
return left.CompareDatum(right)
}
func (e *Evaluator) evalAnd(expr *tipb.Expr) (types.Datum, error) {
leftBool, rightBool, err := e.evalTwoBoolChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
var d types.Datum
if leftBool == 0 || rightBool == 0 {
d.SetInt64(0)
return d, nil
}
if leftBool == compareResultNull || rightBool == compareResultNull {
d.SetNull()
return d, nil
}
d.SetInt64(1)
return d, nil
}
func (e *Evaluator) evalOr(expr *tipb.Expr) (types.Datum, error) {
leftBool, rightBool, err := e.evalTwoBoolChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
var d types.Datum
if leftBool == 1 || rightBool == 1 {
d.SetInt64(1)
return d, nil
}
if leftBool == compareResultNull || rightBool == compareResultNull {
d.SetNull()
return d, nil
}
d.SetInt64(0)
return d, nil
}
func (e *Evaluator) evalTwoBoolChildren(expr *tipb.Expr) (leftBool, rightBool int64, err error) {
left, right, err := e.evalTwoChildren(expr)
if err != nil {
return 0, 0, errors.Trace(err)
}
if left.IsNull() {
leftBool = compareResultNull
} else {
leftBool, err = left.ToBool()
if err != nil {
return 0, 0, errors.Trace(err)
}
}
if right.IsNull() {
rightBool = compareResultNull
} else {
rightBool, err = right.ToBool()
if err != nil {
return 0, 0, errors.Trace(err)
}
}
return
}
func (e *Evaluator) evalTwoChildren(expr *tipb.Expr) (left, right types.Datum, err error) {
if len(expr.Children) != 2 {
err = ErrInvalid.Gen("need 2 operands but got %d", len(expr.Children))
return
}
left, err = e.Eval(expr.Children[0])
if err != nil {
return types.Datum{}, types.Datum{}, errors.Trace(err)
}
right, err = e.Eval(expr.Children[1])
if err != nil {
return types.Datum{}, types.Datum{}, errors.Trace(err)
}
return
}
func (e *Evaluator) evalLike(expr *tipb.Expr) (types.Datum, error) {
target, pattern, err := e.evalTwoChildren(expr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if target.IsNull() || pattern.IsNull() {
return types.Datum{}, nil
}
targetStr, err := target.ToString()
if err != nil {
return types.Datum{}, errors.Trace(err)
}
patternStr, err := pattern.ToString()
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if containsAlphabet(patternStr) {
patternStr = strings.ToLower(patternStr)
targetStr = strings.ToLower(targetStr)
}
mType, trimmedPattern := matchType(patternStr)
var matched bool
switch mType {
case matchExact:
matched = targetStr == trimmedPattern
case matchPrefix:
matched = strings.HasPrefix(targetStr, trimmedPattern)
case matchSuffix:
matched = strings.HasSuffix(targetStr, trimmedPattern)
case matchMiddle:
matched = strings.Index(targetStr, trimmedPattern) != -1
}
if matched {
return types.NewIntDatum(1), nil
}
return types.NewIntDatum(0), nil
}
func containsAlphabet(s string) bool {
for _, r := range s {
if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') {
return true
}
}
return false
}
func matchType(pattern string) (tp int, trimmed string) {
switch len(pattern) {
case 0:
return matchExact, pattern
case 1:
if pattern[0] == '%' {
return matchMiddle, ""
}
return matchExact, pattern
default:
first := pattern[0]
last := pattern[len(pattern)-1]
if first == '%' {
if last == '%' {
return matchMiddle, pattern[1 : len(pattern)-1]
}
return matchSuffix, pattern[1:]
}
if last == '%' {
return matchPrefix, pattern[:len(pattern)-1]
}
return matchExact, pattern
}
}
const (
matchExact = 1
matchPrefix = 2
matchSuffix = 3
matchMiddle = 4
)
func (e *Evaluator) evalNot(expr *tipb.Expr) (types.Datum, error) {
if len(expr.Children) != 1 {
return types.Datum{}, ErrInvalid.Gen("NOT need 1 operand, got %d", len(expr.Children))
}
d, err := e.Eval(expr.Children[0])
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if d.IsNull() {
return d, nil
}
boolVal, err := d.ToBool()
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if boolVal == 1 {
return types.NewIntDatum(0), nil
}
return types.NewIntDatum(1), nil
}
func (e *Evaluator) evalIn(expr *tipb.Expr) (types.Datum, error) {
if len(expr.Children) != 2 {
return types.Datum{}, ErrInvalid.Gen("IN need 2 operand, got %d", len(expr.Children))
}
target, err := e.Eval(expr.Children[0])
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if target.IsNull() {
return types.Datum{}, nil
}
valueListExpr := expr.Children[1]
if valueListExpr.GetTp() != tipb.ExprType_ValueList {
return types.Datum{}, ErrInvalid.Gen("the second children should be value list type")
}
decoded, err := e.decodeValueList(valueListExpr)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
in, err := checkIn(target, decoded.values)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
if in {
return types.NewDatum(1), nil
}
if decoded.hasNull {
return types.Datum{}, nil
}
return types.NewDatum(0), nil
}
// The value list is in sorted order so we can do a binary search.
func checkIn(target types.Datum, list []types.Datum) (bool, error) {
var outerErr error
n := sort.Search(len(list), func(i int) bool {
val := list[i]
cmp, err := val.CompareDatum(target)
if err != nil {
outerErr = errors.Trace(err)
return false
}
return cmp >= 0
})
if outerErr != nil {
return false, errors.Trace(outerErr)
}
if n < 0 || n >= len(list) {
return false, nil
}
cmp, err := list[n].CompareDatum(target)
if err != nil {
return false, errors.Trace(err)
}
return cmp == 0, nil
}
func (e *Evaluator) decodeValueList(valueListExpr *tipb.Expr) (*decodedValueList, error) {
if len(valueListExpr.Val) == 0 {
// Empty value list.
return &decodedValueList{}, nil
}
if e.valueLists == nil {
e.valueLists = make(map[*tipb.Expr]*decodedValueList)
}
decoded := e.valueLists[valueListExpr]
if decoded != nil {
return decoded, nil
}
list, err := codec.Decode(valueListExpr.Val)
if err != nil {
return nil, errors.Trace(err)
}
var hasNull bool
for _, v := range list {
if v.IsNull() {
hasNull = true
}
}
decoded = &decodedValueList{values: list, hasNull: hasNull}
e.valueLists[valueListExpr] = decoded
return decoded, nil
}
func (e *Evaluator) evalArithmetic(expr *tipb.Expr) (types.Datum, error) {
var result types.Datum
left, right, err := e.evalTwoChildren(expr)
if err != nil {
return result, errors.Trace(err)
}
return ComputeArithmetic(expr.GetTp(), left, right)
}
// ComputeArithmetic computes the arithmetic operation on two datums.
func ComputeArithmetic(op tipb.ExprType, left types.Datum, right types.Datum) (types.Datum, error) {
var result types.Datum
a, err := types.CoerceArithmetic(left)
if err != nil {
return result, errors.Trace(err)
}
b, err := types.CoerceArithmetic(right)
if err != nil {
return result, errors.Trace(err)
}
a, b = types.CoerceDatum(a, b)
if a.IsNull() || b.IsNull() {
return result, nil
}
switch op {
case tipb.ExprType_Plus:
return types.ComputePlus(a, b)
case tipb.ExprType_Div:
return types.ComputeDiv(a, b)
default:
return result, errors.Errorf("Unknown binop type: %v", op)
}
}