vendor/github.com/golang/protobuf/ptypes/timestamp.go

   1 // Go support for Protocol Buffers - Google's data interchange format
   2 //
   3 // Copyright 2016 The Go Authors.  All rights reserved.
   4 // https://github.com/golang/protobuf
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  31
  32 package ptypes
  33
  34 // This file implements operations on google.protobuf.Timestamp.
  35
  36 import (
  37         "errors"
  38         "fmt"
  39         "time"
  40
  41         tspb "github.com/golang/protobuf/ptypes/timestamp"
  42 )
  43
  44 const (
  45         // Seconds field of the earliest valid Timestamp.
  46         // This is time.Date(1, 1, 1, 0, 0, 0, 0, time.UTC).Unix().
  47         minValidSeconds = -62135596800
  48         // Seconds field just after the latest valid Timestamp.
  49         // This is time.Date(10000, 1, 1, 0, 0, 0, 0, time.UTC).Unix().
  50         maxValidSeconds = 253402300800
  51 )
  52
  53 // validateTimestamp determines whether a Timestamp is valid.
  54 // A valid timestamp represents a time in the range
  55 // [0001-01-01, 10000-01-01) and has a Nanos field
  56 // in the range [0, 1e9).
  57 //
  58 // If the Timestamp is valid, validateTimestamp returns nil.
  59 // Otherwise, it returns an error that describes
  60 // the problem.
  61 //
  62 // Every valid Timestamp can be represented by a time.Time, but the converse is not true.
  63 func validateTimestamp(ts *tspb.Timestamp) error {
  64         if ts == nil {
  65                 return errors.New("timestamp: nil Timestamp")
  66         }
  67         if ts.Seconds < minValidSeconds {
  68                 return fmt.Errorf("timestamp: %v before 0001-01-01", ts)
  69         }
  70         if ts.Seconds >= maxValidSeconds {
  71                 return fmt.Errorf("timestamp: %v after 10000-01-01", ts)
  72         }
  73         if ts.Nanos < 0 || ts.Nanos >= 1e9 {
  74                 return fmt.Errorf("timestamp: %v: nanos not in range [0, 1e9)", ts)
  75         }
  76         return nil
  77 }
  78
  79 // Timestamp converts a google.protobuf.Timestamp proto to a time.Time.
  80 // It returns an error if the argument is invalid.
  81 //
  82 // Unlike most Go functions, if Timestamp returns an error, the first return value
  83 // is not the zero time.Time. Instead, it is the value obtained from the
  84 // time.Unix function when passed the contents of the Timestamp, in the UTC
  85 // locale. This may or may not be a meaningful time; many invalid Timestamps
  86 // do map to valid time.Times.
  87 //
  88 // A nil Timestamp returns an error. The first return value in that case is
  89 // undefined.
  90 func Timestamp(ts *tspb.Timestamp) (time.Time, error) {
  91         // Don't return the zero value on error, because corresponds to a valid
  92         // timestamp. Instead return whatever time.Unix gives us.
  93         var t time.Time
  94         if ts == nil {
  95                 t = time.Unix(0, 0).UTC() // treat nil like the empty Timestamp
  96         } else {
  97                 t = time.Unix(ts.Seconds, int64(ts.Nanos)).UTC()
  98         }
  99         return t, validateTimestamp(ts)
 100 }
 101
 102 // TimestampNow returns a google.protobuf.Timestamp for the current time.
 103 func TimestampNow() *tspb.Timestamp {
 104         ts, err := TimestampProto(time.Now())
 105         if err != nil {
 106                 panic("ptypes: time.Now() out of Timestamp range")
 107         }
 108         return ts
 109 }
 110
 111 // TimestampProto converts the time.Time to a google.protobuf.Timestamp proto.
 112 // It returns an error if the resulting Timestamp is invalid.
 113 func TimestampProto(t time.Time) (*tspb.Timestamp, error) {
 114         ts := &tspb.Timestamp{
 115                 Seconds: t.Unix(),
 116                 Nanos:   int32(t.Nanosecond()),
 117         }
 118         if err := validateTimestamp(ts); err != nil {
 119                 return nil, err
 120         }
 121         return ts, nil
 122 }
 123
 124 // TimestampString returns the RFC 3339 string for valid Timestamps. For invalid
 125 // Timestamps, it returns an error message in parentheses.
 126 func TimestampString(ts *tspb.Timestamp) string {
 127         t, err := Timestamp(ts)
 128         if err != nil {
 129                 return fmt.Sprintf("(%v)", err)
 130         }
 131         return t.Format(time.RFC3339Nano)
 132 }