In the time before, we just used a RegexSet from the regex crate. That
allocated unconditionally, so there was nothing we could do and it
didn't expose any APIs to reuse that memory. But now that we're using
the lower level regex-automata, we can reuse a PatternSet.
Ideally we would just provide a way for the caller to build a PatternSet
(perhaps via an opaque type) so that we don't have to shuffle data into
a PatternSet and then back into the caller's `Vec<usize>`. But this at
least avoids allocating for every search.
This brings the code in line with my current style. It also inlines the
dozen or so lines of code for FNV hashing instead of bringing in a
micro-crate for it. Finally, it drops the dependency on regex in favor
of using regex-syntax and regex-automata directly.
This leaves the grep-regex crate in tatters. Pretty much the entire
thing needs to be re-worked. The upshot is that it should result in some
big simplifications. I hope.
The idea here is to drop down and actually use regex-automata 0.3
instead of the regex crate itself.
The top-level listing was just getting a bit too long for my taste. So
put all of the code in one directory and shrink the large top-level mess
to a small top-level mess.
NOTE: This commit only contains renames. The subsequent commit will
actually make ripgrep build again. We do it this way with the naive hope
that this will make it easier for git history to track the renames.
Sigh.
