github.com/m3db/m3@v1.5.0/src/x/clock/offset_clock.go (about)

     1  // Copyright (c) 2021 Uber Technologies, Inc.
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     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
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     9  //
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    11  // all copies or substantial portions of the Software.
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    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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    19  // THE SOFTWARE.
    20  
    21  package clock
    22  
    23  import (
    24  	"time"
    25  )
    26  
    27  // OffsetClock represents offset clock which returns current time from the initial seed time value.
    28  type OffsetClock struct {
    29  	timeDelta time.Duration
    30  	nowFn     NowFn
    31  }
    32  
    33  // NewOffsetClock returns new offset clock.
    34  func NewOffsetClock(offsetTime time.Time, nowFn NowFn) OffsetClock {
    35  	return OffsetClock{nowFn: nowFn, timeDelta: offsetTime.Sub(nowFn())}
    36  }
    37  
    38  // NewOffsetClockFromTimeDelta returns new offset clock that has time shifted by timeDelta duration.
    39  func NewOffsetClockFromTimeDelta(timeDelta time.Duration, nowFn NowFn) OffsetClock {
    40  	return OffsetClock{nowFn: nowFn, timeDelta: timeDelta}
    41  }
    42  
    43  // Now returns current time with time offset taken into account.
    44  func (c OffsetClock) Now() time.Time {
    45  	now := c.nowFn()
    46  	return now.Add(c.timeDelta)
    47  }