[Omake] symlink (FAT filesystem)

[Aleksey Nogin]

Hi Matthieu,

On 11.10.2006 04:10, Matthieu Dubuget wrote:

> Hello,
> 
> in order to test my project on different platforms, I put everything on 
> my USB key, which allow me to switch between windows and linux easily. 
> Of course, the filesystem of my key is FAT: files cannot be symlinked, 
> even if connected to my linux box.
> 
> The problem is that Common.om <http://Common.om> uses  $(OSTYPE) in 
> order to modify symlink definition.
> 
> This is incorrect: the right test should be related to the filesystem 
> which seems not to be a trivial problem: there are a lot of different 
> filesystems for only one computer...

This is true - assuming that any Unix-like system can do symlinks is 
very simplistic, thanks for pointing it out. I've filed a bug report 
outlining this and related issues and proposing a solution - 
http://bugzilla.metaprl.org/show_bug.cgi?id=602 .

> As a workaround, I added this in my OMakeroot:
> symlink(src, dst) =
>         return(cp -f $(src) $(dst))
> 
> Is there any better solution?

One option would be to try ln first and revert to cp if ln fails.

For example,

Shell. +=
   ln-or-cp(argv) =
     src = $(file $(nth 0, $(argv)))
     dst = $(file $(nth 1, $(argv)))
     ln -sf $(in $(dirof $(dst)), $(src)) $(dst) || cp -f $(src) $(dst)

symlink(src, dst) =
    return(ln-or-cp $(src) $(dst))

A slightly cleaner (and probably more efficient) option would be to 
define myln using the built-in symlink function.

Shell. +=
    ln-or-cp(argv) =
       src = $(file $(nth 0, $(argv)))
       dst = $(file $(nth 1, $(argv)))
       try
          src.symlink($(dst))
       default
          cp -f $(src) $(dst)

Unfortunately, the built-in symlink function is currently shadowed by 
the Common.om (not sure how this happened) so this would not work unless 
the Common.om itself is fixed and/or one of the two different "symlink" 
functions is renamed. As I proposed in bug 602, one solution would be to 
implement the ln-or-cp using the built-in symlink function and then get 
rid of the other symlink function (the one defined in Common.om) and use 
the new ln-or-cp in rules directly.

Aleksey

P.S. Sorry for the slow response.