[MERGE] Speed up log --short / --line

[Michael Hudson]

Aaron Bentley wrote:
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> Robert Collins wrote:
>> On Mon, 2008-03-24 at 16:36 -0400, Aaron Bentley wrote:
> 
>>> This patch optimizes log operations, by providing a fast-path for
>>> calculating view revisions when no merged revisions will be shown.  I've
>>> written it as an alternative to Michael Hudson's cheaper-simple-logging
>>> patch.
>> Ok, And it looks decent to me; however - you don't say anything about
>> why your patch is preferrable, and I'm probably just missing context
>> after easter :). 
> 
> One reason is that cheaper-simple-logging is slower than both bzr.dev
> and fast-log when logging large numbers of revisions, and I did say that.
> 
> The other reason is code cleanliness; Michael didn't attempt any
> refactoring, just made the existing _show_log function larger.  He also
> reimplemented Repository.iter_reverse_revision_history.

I never really expected my branch to be merged, I was just hacking and 
wanted to get something sent to the list before I went away for a week. 
  I'm really glad you did it properly :)

Cheers,
mwh