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// 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 oracles
import (
"context"
"sync"
"time"
"github.com/pingcap/tidb/store/tikv/oracle"
)
var _ oracle.Oracle = &localOracle{}
type localOracle struct {
sync.Mutex
lastTimeStampTS uint64
n uint64
hook *struct {
currentTime time.Time
}
}
// NewLocalOracle creates an Oracle that uses local time as data source.
func NewLocalOracle() oracle.Oracle {
return &localOracle{}
}
func (l *localOracle) IsExpired(lockTS uint64, TTL uint64) bool {
now := time.Now()
if l.hook != nil {
now = l.hook.currentTime
}
return oracle.GetPhysical(now) >= oracle.ExtractPhysical(lockTS)+int64(TTL)
}
func (l *localOracle) GetTimestamp(context.Context) (uint64, error) {
l.Lock()
defer l.Unlock()
now := time.Now()
if l.hook != nil {
now = l.hook.currentTime
}
physical := oracle.GetPhysical(now)
ts := oracle.ComposeTS(physical, 0)
if l.lastTimeStampTS == ts {
l.n++
return ts + l.n, nil
}
l.lastTimeStampTS = ts
l.n = 0
return ts, nil
}
func (l *localOracle) GetTimestampAsync(ctx context.Context) oracle.Future {
return &future{
ctx: ctx,
l: l,
}
}
func (l *localOracle) GetLowResolutionTimestamp(ctx context.Context) (uint64, error) {
return l.GetTimestamp(ctx)
}
func (l *localOracle) GetLowResolutionTimestampAsync(ctx context.Context) oracle.Future {
return l.GetTimestampAsync(ctx)
}
type future struct {
ctx context.Context
l *localOracle
}
func (f *future) Wait() (uint64, error) {
return f.l.GetTimestamp(f.ctx)
}
// UntilExpired implement oracle.Oracle interface.
func (l *localOracle) UntilExpired(lockTimeStamp uint64, TTL uint64) int64 {
now := time.Now()
if l.hook != nil {
now = l.hook.currentTime
}
return oracle.ExtractPhysical(lockTimeStamp) + int64(TTL) - oracle.GetPhysical(now)
}
func (l *localOracle) Close() {
}