Re: [PATCH] gitweb: Use File::Find::find in git_get_projects_list

From: Junio C Hamano <junkio@cox.net>
Date: Sep 14, 2006, 18:32 UTC
Message-ID: <7vbqpi47vi.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <7v1wqe6buv.fsf@assigned-by-dhcp.cox.net>

Junio C Hamano <junkio@cox.net> writes:

Show 26 quoted lines

> Jakub Narebski <jnareb@gmail.com> writes:
>
>> Not true. Link to directory is both -d $_ and -l $_, so
>>
>> 	return unless (-d $_ || (-l $_ && -d readlink($_)));
>>
>> is not needed.
>
> I think you mis-read what I said.  I first wondered why you did
> not say "return unless -d _" and wrote (seemingly more
> inefficient) "return unless -d $_".  The comment is to clarify
> why '$' is needed.
>
> In other words, after this setup:
>
>         $ rm -fr d dl
>         $ mkdir d
>         $ ln -s d dl
>
> you do not see an output from this:
>
>         $ perl -e 'lstat "dl"; print "is-dir\n" if -d _;'
>
> but you do from this:
>
>         $ perl -e 'lstat "dl"; print "is-dir\n" if -d "dl";'

Side note:

While

	return unless -d $_

there is definitely more correct than "return unless -d _" which is not, it is not the most efficient. Because you use fast_xxx, you know the last stat was lstat so "-d _" would be true if the thing you are looking at is a real directory and will be a zero-cost operation. The only case you want to be careful is a symlink pointing at a directory, so

	return unless ((-d _) || (-l _ && -d $_))

would be more efficient.

I have a strange suspicion that Merlyn will soon join us with more expertise if we keep talking about Perl ;-)