bug#44753: 27.1; arc-mode does not extract marked files

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> However, the implementation of archive-copy-file doesn't seem to be
> easily scalable to what Vladimir requested.  It is also sub-optimal
> (to say the least) to extract files by going through a temporary
> buffer, since every archive type has some way of extracting files
> directly.

That's true.  arc-mode is a pretty ambitious package, allowing editing
etc of files in the archives, where some of the backends parse the files
directly in elisp, and some use external programs.

Which is probably why it took so long for somebody to write a simple
"copy" command.

> If nothing else, this will cause serious problems with
> encoding, especially when several files are extracted at once that
> happen to be encoded differently.  And the speed will also be much
> slower than if we use the archiver program to do the extraction.

If we're doing extraction to file directly, then I think arc-mode should
be rewritten to just use external commands for everything, and not
attempt to parse anything in Lisp.

I don't think the speed thing is that vital -- we've lived with this
forever (i.e., using non-native commands for looking at file members).

As for coding systems -- do the native commands do any decoding?  I'd
expect unpacking a zip file to give me exactly the bytes that were in
the files before packing them.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no