github.com/FUSIONFoundation/efsn@v3.6.2-0.20200916075423-dbb5dd5d2cc7+incompatible/swarm/storage/mru/timestampprovider.go (about)

     1  // Copyright 2018 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package mru
    18  
    19  import (
    20  	"encoding/binary"
    21  	"time"
    22  )
    23  
    24  // TimestampProvider sets the time source of the mru package
    25  var TimestampProvider timestampProvider = NewDefaultTimestampProvider()
    26  
    27  // Encodes a point in time as a Unix epoch
    28  type Timestamp struct {
    29  	Time uint64 // Unix epoch timestamp, in seconds
    30  }
    31  
    32  // 8 bytes uint64 Time
    33  const timestampLength = 8
    34  
    35  // timestampProvider interface describes a source of timestamp information
    36  type timestampProvider interface {
    37  	Now() Timestamp // returns the current timestamp information
    38  }
    39  
    40  // binaryGet populates the timestamp structure from the given byte slice
    41  func (t *Timestamp) binaryGet(data []byte) error {
    42  	if len(data) != timestampLength {
    43  		return NewError(ErrCorruptData, "timestamp data has the wrong size")
    44  	}
    45  	t.Time = binary.LittleEndian.Uint64(data[:8])
    46  	return nil
    47  }
    48  
    49  // binaryPut Serializes a Timestamp to a byte slice
    50  func (t *Timestamp) binaryPut(data []byte) error {
    51  	if len(data) != timestampLength {
    52  		return NewError(ErrCorruptData, "timestamp data has the wrong size")
    53  	}
    54  	binary.LittleEndian.PutUint64(data, t.Time)
    55  	return nil
    56  }
    57  
    58  type DefaultTimestampProvider struct {
    59  }
    60  
    61  // NewDefaultTimestampProvider creates a system clock based timestamp provider
    62  func NewDefaultTimestampProvider() *DefaultTimestampProvider {
    63  	return &DefaultTimestampProvider{}
    64  }
    65  
    66  // Now returns the current time according to this provider
    67  func (dtp *DefaultTimestampProvider) Now() Timestamp {
    68  	return Timestamp{
    69  		Time: uint64(time.Now().Unix()),
    70  	}
    71  }