ducky/devices

Paddy 2016-01-02 Parent:c24a6c5fcd8c

19:51ad0db105c8 Go to Latest

ducky/devices/context.go

Update trout to fix routing bug. Update to tip on trout to fix the routing bug that was causing us such issues. See the commit message of trout at 3df515f0cec5 for more details.

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1 package devices
2
3 import (
4 "errors"
5
6 "golang.org/x/net/context"
7 )
8
9 const (
10 storerKey = "code.secondbit.org/ducky/devices.hg#Storer"
11 )
12
13 var (
14 // ErrNoStorerSet is returned when the Context has no Storer set in it.
15 ErrNoStorerSet = errors.New("storerKey not set in Context")
16 // ErrStorerKeyNotStorer is returned when there's a value in the Context for storerKey, but it's not a Storer.
17 ErrStorerKeyNotStorer = errors.New("the value for storerKey does not fulfill the Storer interface")
18 )
19
20 // GetStorer returns the Storer associated with the passed Context.
21 // If no Storer is set, ErrNoStorerSet will be returned.
22 // If something that is not a Storer is set using the Storer's key,
23 // ErrStorerKeyNotStorer will be returned.
24 func GetStorer(c context.Context) (Storer, error) {
25 val := c.Value(storerKey)
26 if val == nil {
27 return nil, ErrNoStorerSet
28 }
29 storer, ok := val.(Storer)
30 if !ok {
31 return nil, ErrStorerKeyNotStorer
32 }
33 return storer, nil
34 }
35
36 // WithStorer returns a Context that extends from the passed Context,
37 // but includes or overwrites the Storer key with the passed Storer.
38 func WithStorer(c context.Context, storer Storer) context.Context {
39 return context.WithValue(c, storerKey, storer)
40 }