Re: [boost] [filesystem] "leaf"

From: Martin Wille (mw8329_at_[hidden])
Date: 2008-05-29 13:06:50

Beman Dawes wrote:
> Beman Dawes wrote:
>> ...An
>> alternative set I'd be comfortable with would be tail() for the current 
>> leaf() and head_path() for the current branch_path().
> 
> Hum... After sending that, I read Johan RÃ¥de's "parent" suggestion.
> 
> I really like parent_path() for the current branch_path().

Sorry for the bikeshedding, but I really don't like parent_path. The 
problem I see is related to symbolic links. "parent" suggests a parent 
directory, even though parent_path() might return something that is not 
the parent directory of a link target. I think the naming should reflect 
the fact that we're operating on names only, not on an actual filesystem 
structure. So, IMHO, "basename" is a better choice than anything 
containing "parent".

A sketch might help to understand the situation; consider this structure:

/x:
drwxr-xr-x 2 root root 72 2008-05-29 18:52 left
drwxr-xr-x 3 root root 72 2008-05-29 18:52 right1

/x/left:
-rw-r--r-- 1 root root 5 2008-05-29 18:52 foo

/x/right1:
drwxr-xr-x 2 root root 72 2008-05-29 18:55 right2

/x/right1/right2:
lrwxrwxrwx 1 root root 10 2008-05-29 18:55 bar -> ../../left

basename(/x/right1/right2/bar) will return /x/right1/right2

open(basename(/x/right1/right2/bar)) will open something different than 
open((/x/right1/right2/bar/..)), as can be demonstrated by using ls:

 > ls -l /x/right1/right2
lrwxrwxrwx 1 root root 10 2008-05-29 18:55 bar -> ../../left

 > ls -l /x/right1/right2/bar/..
drwxr-xr-x 2 root root 72 2008-05-29 18:52 left
drwxr-xr-x 3 root root 72 2008-05-29 18:52 right1

So, "basename()" and "parent_of()" should be considered operations on 
different domains (path names vs filesystem).

Regards,
m