github.com/KinWaiYuen/client-go/v2@v2.5.4/oracle/oracles/local.go (about)

     1  // Copyright 2021 TiKV Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // NOTE: The code in this file is based on code from the
    16  // TiDB project, licensed under the Apache License v 2.0
    17  //
    18  // https://github.com/pingcap/tidb/tree/cc5e161ac06827589c4966674597c137cc9e809c/store/tikv/oracle/oracles/local.go
    19  //
    20  
    21  // Copyright 2016 PingCAP, Inc.
    22  //
    23  // Licensed under the Apache License, Version 2.0 (the "License");
    24  // you may not use this file except in compliance with the License.
    25  // You may obtain a copy of the License at
    26  //
    27  //     http://www.apache.org/licenses/LICENSE-2.0
    28  //
    29  // Unless required by applicable law or agreed to in writing, software
    30  // distributed under the License is distributed on an "AS IS" BASIS,
    31  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    32  // See the License for the specific language governing permissions and
    33  // limitations under the License.
    34  
    35  package oracles
    36  
    37  import (
    38  	"context"
    39  	"sync"
    40  	"time"
    41  
    42  	"github.com/KinWaiYuen/client-go/v2/oracle"
    43  )
    44  
    45  var _ oracle.Oracle = &localOracle{}
    46  
    47  type localOracle struct {
    48  	sync.Mutex
    49  	lastTimeStampTS uint64
    50  	n               uint64
    51  	hook            *struct {
    52  		currentTime time.Time
    53  	}
    54  }
    55  
    56  // NewLocalOracle creates an Oracle that uses local time as data source.
    57  func NewLocalOracle() oracle.Oracle {
    58  	return &localOracle{}
    59  }
    60  
    61  func (l *localOracle) IsExpired(lockTS, TTL uint64, _ *oracle.Option) bool {
    62  	now := time.Now()
    63  	if l.hook != nil {
    64  		now = l.hook.currentTime
    65  	}
    66  	expire := oracle.GetTimeFromTS(lockTS).Add(time.Duration(TTL) * time.Millisecond)
    67  	return !now.Before(expire)
    68  }
    69  
    70  func (l *localOracle) GetTimestamp(ctx context.Context, _ *oracle.Option) (uint64, error) {
    71  	l.Lock()
    72  	defer l.Unlock()
    73  	now := time.Now()
    74  	if l.hook != nil {
    75  		now = l.hook.currentTime
    76  	}
    77  	ts := oracle.GoTimeToTS(now)
    78  	if l.lastTimeStampTS == ts {
    79  		l.n++
    80  		return ts + l.n, nil
    81  	}
    82  	l.lastTimeStampTS = ts
    83  	l.n = 0
    84  	return ts, nil
    85  }
    86  
    87  func (l *localOracle) GetTimestampAsync(ctx context.Context, _ *oracle.Option) oracle.Future {
    88  	return &future{
    89  		ctx: ctx,
    90  		l:   l,
    91  	}
    92  }
    93  
    94  func (l *localOracle) GetLowResolutionTimestamp(ctx context.Context, opt *oracle.Option) (uint64, error) {
    95  	return l.GetTimestamp(ctx, opt)
    96  }
    97  
    98  func (l *localOracle) GetLowResolutionTimestampAsync(ctx context.Context, opt *oracle.Option) oracle.Future {
    99  	return l.GetTimestampAsync(ctx, opt)
   100  }
   101  
   102  // GetStaleTimestamp return physical
   103  func (l *localOracle) GetStaleTimestamp(ctx context.Context, txnScope string, prevSecond uint64) (ts uint64, err error) {
   104  	return oracle.GoTimeToTS(time.Now().Add(-time.Second * time.Duration(prevSecond))), nil
   105  }
   106  
   107  type future struct {
   108  	ctx context.Context
   109  	l   *localOracle
   110  }
   111  
   112  func (f *future) Wait() (uint64, error) {
   113  	return f.l.GetTimestamp(f.ctx, &oracle.Option{})
   114  }
   115  
   116  // UntilExpired implement oracle.Oracle interface.
   117  func (l *localOracle) UntilExpired(lockTimeStamp, TTL uint64, opt *oracle.Option) int64 {
   118  	now := time.Now()
   119  	if l.hook != nil {
   120  		now = l.hook.currentTime
   121  	}
   122  	return oracle.ExtractPhysical(lockTimeStamp) + int64(TTL) - oracle.GetPhysical(now)
   123  }
   124  
   125  func (l *localOracle) Close() {
   126  }