tomb: update API

As discussed on IRC:

Rename Fatal and Fatalf to Kill and Killf.

Make zero-value of Tomb good to use, and as a consequence, make Dead
and Dying into methods rather than fields.

https://code.launchpad.net/~rogpeppe/tomb/update-api/+merge/96158

(do not edit description out of merge proposal)

[rog, 2012-03-06 15:46:11]

Please take a look.

[rog, 2012-03-06 15:50:09]

Please take a look.

[niemeyer, 2012-03-06 16:07:34]

https://codereview.appspot.com/5755055/diff/3001/tomb.go
File tomb.go (right):

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode44
tomb.go:44: // created or already alive. Once Kill is called with an
s/Kill/Kill or Killf/, as before please.

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode80
tomb.go:80: if t.state == uninitialized {
if t.dead == nil {
    t.dead = make(...)
    t.dying = make(...)
    t.reason = ErrStillRunning
}

We don't need "state".

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode130
tomb.go:130: reason = errCleanKill
nil itself is errCleanKill. We don't need a second way to flag this.

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode136
tomb.go:136: if t.state == running {
if t.reason != ErrStillRunning

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode162
tomb.go:162: }
The switch is unnecessary with the suggested change. Just return t.reason at all
times.

[rog, 2012-03-06 16:27:24]

Please take a look.

[rog, 2012-03-06 16:30:18]

Please take a look.

[rog, 2012-03-06 16:30:41]

much better with those changes, thanks.
PTAL.

https://codereview.appspot.com/5755055/diff/3001/tomb.go
File tomb.go (right):

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode44
tomb.go:44: // created or already alive. Once Kill is called with an
On 2012/03/06 16:07:35, niemeyer wrote:
> s/Kill/Kill or Killf/, as before please.

Done.

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode80
tomb.go:80: if t.state == uninitialized {
On 2012/03/06 16:07:35, niemeyer wrote:
> if t.dead == nil {
>     t.dead = make(...)
>     t.dying = make(...)
>     t.reason = ErrStillRunning
> }
> 
> We don't need "state".

Done.

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode130
tomb.go:130: reason = errCleanKill
On 2012/03/06 16:07:35, niemeyer wrote:
> nil itself is errCleanKill. We don't need a second way to flag this.

Done.

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode136
tomb.go:136: if t.state == running {
On 2012/03/06 16:07:35, niemeyer wrote:
> if t.reason != ErrStillRunning

Done.

https://codereview.appspot.com/5755055/diff/3001/tomb.go#newcode162
tomb.go:162: }
On 2012/03/06 16:07:35, niemeyer wrote:
> The switch is unnecessary with the suggested change. Just return t.reason at
all
> times.

Done.

[niemeyer, 2012-03-06 17:06:54]

A couple of trivials, and should be ready to submit.

https://codereview.appspot.com/5755055/diff/6003/tomb.go
File tomb.go (right):

https://codereview.appspot.com/5755055/diff/6003/tomb.go#newcode106
tomb.go:106: t.init()
init isn't needed here.

https://codereview.appspot.com/5755055/diff/6003/tomb_test.go
File tomb_test.go (right):

https://codereview.appspot.com/5755055/diff/6003/tomb_test.go#newcode19
tomb_test.go:19: // the Kill reason flags the goroutine as dying
s/Kill/nil/

https://codereview.appspot.com/5755055/diff/6003/tomb_test.go#newcode24
tomb_test.go:24: // a non-Kill reason now will override Kill
s/Kill/nil/g

[rog, 2012-03-06 17:16:48]

Please take a look.

[rog, 2012-03-06 17:17:33]

https://codereview.appspot.com/5755055/diff/6003/tomb.go
File tomb.go (right):

https://codereview.appspot.com/5755055/diff/6003/tomb.go#newcode106
tomb.go:106: t.init()
On 2012/03/06 17:06:55, niemeyer wrote:
> init isn't needed here.

Done.

https://codereview.appspot.com/5755055/diff/6003/tomb_test.go
File tomb_test.go (right):

https://codereview.appspot.com/5755055/diff/6003/tomb_test.go#newcode19
tomb_test.go:19: // the Kill reason flags the goroutine as dying
On 2012/03/06 17:06:55, niemeyer wrote:
> s/Kill/nil/

Done.

https://codereview.appspot.com/5755055/diff/6003/tomb_test.go#newcode24
tomb_test.go:24: // a non-Kill reason now will override Kill
On 2012/03/06 17:06:55, niemeyer wrote:
> s/Kill/nil/g

Done.

[niemeyer, 2012-03-06 18:36:00]

*** Submitted:

tomb: update API

- Rename Fatal and Fatalf to Kill and Killf.

- The Stop error value is gone. Use nil now.

- Err will now return ErrStillRunning if the goroutine isn't dead
  yet, which means a nil return reflects an actual nil Kill call.

- Make zero-value of Tomb good to use, and as a consequence, make
  Dead and Dying into methods rather than fields.

R=niemeyer
CC=
https://codereview.appspot.com/5755055