vendor/github.com/aws/aws-sdk-go/aws/context.go

   1 package aws
   2
   3 import (
   4         "time"
   5 )
   6
   7 // Context is an copy of the Go v1.7 stdlib's context.Context interface.
   8 // It is represented as a SDK interface to enable you to use the "WithContext"
   9 // API methods with Go v1.6 and a Context type such as golang.org/x/net/context.
  10 //
  11 // See https://golang.org/pkg/context on how to use contexts.
  12 type Context interface {
  13         // Deadline returns the time when work done on behalf of this context
  14         // should be canceled. Deadline returns ok==false when no deadline is
  15         // set. Successive calls to Deadline return the same results.
  16         Deadline() (deadline time.Time, ok bool)
  17
  18         // Done returns a channel that's closed when work done on behalf of this
  19         // context should be canceled. Done may return nil if this context can
  20         // never be canceled. Successive calls to Done return the same value.
  21         Done() <-chan struct{}
  22
  23         // Err returns a non-nil error value after Done is closed. Err returns
  24         // Canceled if the context was canceled or DeadlineExceeded if the
  25         // context's deadline passed. No other values for Err are defined.
  26         // After Done is closed, successive calls to Err return the same value.
  27         Err() error
  28
  29         // Value returns the value associated with this context for key, or nil
  30         // if no value is associated with key. Successive calls to Value with
  31         // the same key returns the same result.
  32         //
  33         // Use context values only for request-scoped data that transits
  34         // processes and API boundaries, not for passing optional parameters to
  35         // functions.
  36         Value(key interface{}) interface{}
  37 }
  38
  39 // BackgroundContext returns a context that will never be canceled, has no
  40 // values, and no deadline. This context is used by the SDK to provide
  41 // backwards compatibility with non-context API operations and functionality.
  42 //
  43 // Go 1.6 and before:
  44 // This context function is equivalent to context.Background in the Go stdlib.
  45 //
  46 // Go 1.7 and later:
  47 // The context returned will be the value returned by context.Background()
  48 //
  49 // See https://golang.org/pkg/context for more information on Contexts.
  50 func BackgroundContext() Context {
  51         return backgroundCtx
  52 }
  53
  54 // SleepWithContext will wait for the timer duration to expire, or the context
  55 // is canceled. Which ever happens first. If the context is canceled the Context's
  56 // error will be returned.
  57 //
  58 // Expects Context to always return a non-nil error if the Done channel is closed.
  59 func SleepWithContext(ctx Context, dur time.Duration) error {
  60         t := time.NewTimer(dur)
  61         defer t.Stop()
  62
  63         select {
  64         case <-t.C:
  65                 break
  66         case <-ctx.Done():
  67                 return ctx.Err()
  68         }
  69
  70         return nil
  71 }