[PATCH 2 of 2] util: add length argument to util.buffer()

[Yuya Nishihara]

On Sun, 15 Jan 2017 13:42:52 +0530, Pulkit Goyal wrote:
> # HG changeset patch
> # User Pulkit Goyal <7895pulkit at gmail.com>
> # Date 1484404515 -19800
> #      Sat Jan 14 20:05:15 2017 +0530
> # Node ID 79f98c1b8d718bfa94f12eb62872598ad7ec9c2e
> # Parent  9dc4d056d85a041b2b28587b3b84608b1f0903a5
> util: add length argument to util.buffer()
> 
> util.buffer() either returns inbuilt buffer function or defines a new one which
> slices. The inbuilt buffer() also has a length argument which is missing from
> the ones whe defined. This patch adds that length argument.
> 
> diff -r 9dc4d056d85a -r 79f98c1b8d71 mercurial/util.py
> --- a/mercurial/util.py	Sat Jan 14 01:23:07 2017 +0530
> +++ b/mercurial/util.py	Sat Jan 14 20:05:15 2017 +0530
> @@ -238,10 +238,14 @@
>      buffer = buffer
>  except NameError:
>      if not pycompat.ispy3:
> -        def buffer(sliceable, offset=0):
> +        def buffer(sliceable, offset=0, length=None):
> +            if length:
> +                return sliceable[offset:offset + length]
>              return sliceable[offset:]
>      else:
> -        def buffer(sliceable, offset=0):
> +        def buffer(sliceable, offset=0, length=None):
> +            if length:
> +                return memoryview(sliceable)[offset:offset + length]
>              return memoryview(sliceable)[offset:]

Here length=0 and None have different meanings. Can you resend V2?