140 lines
3.8 KiB
Go
140 lines
3.8 KiB
Go
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package expression
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import (
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"fmt"
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"strings"
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"time"
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"github.com/juju/errors"
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"github.com/pingcap/tidb/context"
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"github.com/pingcap/tidb/mysql"
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"github.com/pingcap/tidb/util/types"
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)
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// DateArithType is type for DateArith option.
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type DateArithType byte
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const (
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// DateAdd is to run date_add function option.
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// See: https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_date-add
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DateAdd DateArithType = iota + 1
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// DateSub is to run date_sub function option.
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// See: https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_date-sub
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DateSub
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)
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// DateArith is used for dealing with addition and substraction of time.
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type DateArith struct {
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Op DateArithType
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Unit string
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Date Expression
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Interval Expression
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}
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func (da *DateArith) isAdd() bool {
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if da.Op == DateAdd {
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return true
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}
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return false
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}
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// Clone implements the Expression Clone interface.
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func (da *DateArith) Clone() Expression {
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n := *da
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return &n
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}
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// IsStatic implements the Expression IsStatic interface.
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func (da *DateArith) IsStatic() bool {
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return da.Date.IsStatic() && da.Interval.IsStatic()
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}
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// Accept implements the Visitor Accept interface.
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func (da *DateArith) Accept(v Visitor) (Expression, error) {
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return v.VisitDateArith(da)
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}
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// String implements the Expression String interface.
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func (da *DateArith) String() string {
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var str string
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if da.isAdd() {
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str = "DATE_ADD"
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} else {
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str = "DATE_SUB"
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}
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return fmt.Sprintf("%s(%s, INTERVAL %s %s)", str, da.Date, da.Interval, strings.ToUpper(da.Unit))
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}
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// Eval implements the Expression Eval interface.
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func (da *DateArith) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error) {
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t, years, months, days, durations, err := da.evalArgs(ctx, args)
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if t.IsZero() || err != nil {
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return nil, errors.Trace(err)
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}
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if !da.isAdd() {
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years, months, days, durations = -years, -months, -days, -durations
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}
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t.Time = t.Time.Add(durations)
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t.Time = t.Time.AddDate(int(years), int(months), int(days))
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// "2011-11-11 10:10:20.000000" outputs "2011-11-11 10:10:20".
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if t.Time.Nanosecond() == 0 {
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t.Fsp = 0
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}
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return t, nil
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}
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func (da *DateArith) evalArgs(ctx context.Context, args map[interface{}]interface{}) (
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mysql.Time, int64, int64, int64, time.Duration, error) {
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dVal, err := da.Date.Eval(ctx, args)
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if dVal == nil || err != nil {
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return mysql.ZeroTimestamp, 0, 0, 0, 0, errors.Trace(err)
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}
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dValStr, err := types.ToString(dVal)
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if err != nil {
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return mysql.ZeroTimestamp, 0, 0, 0, 0, errors.Trace(err)
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}
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f := types.NewFieldType(mysql.TypeDatetime)
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f.Decimal = mysql.MaxFsp
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dVal, err = types.Convert(dValStr, f)
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if dVal == nil || err != nil {
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return mysql.ZeroTimestamp, 0, 0, 0, 0, errors.Trace(err)
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}
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t, ok := dVal.(mysql.Time)
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if !ok {
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return mysql.ZeroTimestamp, 0, 0, 0, 0, errors.Errorf("need time type, but got %T", dVal)
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}
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iVal, err := da.Interval.Eval(ctx, args)
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if iVal == nil || err != nil {
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return mysql.ZeroTimestamp, 0, 0, 0, 0, errors.Trace(err)
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}
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iValStr, err := types.ToString(iVal)
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if err != nil {
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return mysql.ZeroTimestamp, 0, 0, 0, 0, errors.Trace(err)
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}
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years, months, days, durations, err := mysql.ExtractTimeValue(da.Unit, strings.TrimSpace(iValStr))
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if err != nil {
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return mysql.ZeroTimestamp, 0, 0, 0, 0, errors.Trace(err)
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}
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return t, years, months, days, durations, nil
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}
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