Re: dired-do-find-regexp failure with latin-1 encoding

[Dmitry Gutov]

On 29.11.2020 19:18, Eli Zaretskii wrote:

> > That wouldn't be easy, but some script that performs conversion based on
> > file contents could work.
>
> It could work in principle, but I think in practice it will not be
> faster than doing everything in Emacs Lisp, because each file will
> need to be read twice.

It will certainly be faster if the host if remote.

On a local machine, you might be right, but we'd have to benchmark to be 
sure.

If the calls to the conversion program are done in parallel to the 
subsequent searches, reading the file twice might not be a problem (with 
the benefit of a disk cache). And if rg itself performs the search 
faster than Emacs' regexp engine, that can also be a factor.

Depends on process spawning overhead, I suppose.

> > > It would be brittle, unless that program actually reads the entire
> > > file (which will be slow).
> >
> > How does Emacs do it? Does it read until the end of the file?
>
> No, just a small initial part of it.  That's one reason why the
> results are not guaranteed to be correct.

But if we consider that approach good enough for Emacs, it should 
probably be good enough for doing a search from inside Emacs.