[PATCH] log: make file log slow path usable on large repos

[Nikolaj Sjujskij]

> # HG changeset patch
> # User Durham Goode <durham at fb.com>
> # Date 1378867774 25200
> #      Tue Sep 10 19:49:34 2013 -0700
> # Node ID 73303bff81aaa188c0113791f0147f9e13a9eef8
> # Parent  c821473150d2cc0c75c74a0292e9a060eb19bc36
> log: make file log slow path usable on large repos
>
> Running "hg log <pattern or directory>" on large repos took a very, very  
> long
> time because it first read ctx.files() for every commit before even  
> starting to
> process the results.
>
> This change makes the ctx.files() check lazy, which makes the command  
> start producing results immediately.
Sounds like somehow related to issue 4002 ("hg log FILE is slow") [1]
Probably would help issue 3948 ("`log --patch` is very slow")[2] as well

[1]: http://bz.selenic.com/show_bug.cgi?id=4002
[2]: http://bz.selenic.com/show_bug.cgi?id=3948