It turns out our fast path for -w/--word-regexp wasn't quite correct in
some cases. Namely, we use `(?m:^|\W)(<original-regex>)(?m:\W|$)` as the
implementation of -w/--word-regexp since `\b(<original-regex>)\b` has
some unintuitive results in certain cases, specifically when
<original-regex> matches non-word characters at match boundaries.
The problem is that using this formulation means that you need to
extract the capture group around <original-regex> to find the "real"
match, since the surrounding (^|\W) and (\W|$) aren't part of the match.
This is fine, but the capture group engine is usually slow, so we have a
fast path where we try to deduce the correct match boundary after an
initial match (before running capture groups). The problem is that doing
this is rather tricky because it's hard to know, in general, whether the
`^` or the `\W` matched.
This still doesn't seem quite right overall, but we at least fix one
more case.
Fixes#2574
This does a little bit of refactoring so that we can pass both a
ConfiguredHIR and a Regex to the inner literal extraction routine.
One downside of this approach is that a regex object hangs on to a
ConfiguredHIR. But the extra memory usage is probably negligible. A
benefit though is that converting the HIR to its concrete syntax is now
lazy and only happens when logging is enabled.
Previously, ripgrep core was responsible for escaping regex patterns and
implementing the --line-regexp flag. This commit moves that
responsibility down into the matchers such that ripgrep just needs to
hand the patterns it gets off to the matcher builder. The builder will
then take care of escaping and all that.
This was done to make pattern construction completely owned by the
matcher builders. With the arrival regex-automata, this means we can
move to the HIR very quickly and then never move back to the concrete
syntax. We can then build our regex directly from the HIR. This overall
can save quite a bit of time, especially when searching for large
dictionaries.
We still aren't quite as fast as GNU grep when searching something on
the scale of /usr/share/dict/words, but we are basically within spitting
distance. Prior to this, we were about an order of magnitude slower.
This architecture in particular lets us write a pretty simple fast path
that avoids AST parsing and HIR translation entirely: the case where one
is just searching for a literal. In that case, we can hand construct the
HIR directly.
Just some small polishing. We also get rid of thread_local in favor of
using regex-automata, mostly just in the name of reducing dependencies.
(We should eventually be able to drop thread_local completely.)
This is a weird bug where our optimization for handling -w more quickly
than we would otherwise failed. In particular, if the original regex can
match the empty string, then our word boundary detection would produce
invalid indices to the start the next search at. We "fix" it by simply
bailing when the indices are known to be incorrect.
This wasn't a problem in a previous release since ripgrep 13 tweaked how
word boundaries are detected in commit efd9cfb2.
Fixes#1891
This commit hacks in a bug fix for handling look-around across multiple
lines. The main problem is that by the time the matching lines are sent
to the printer, the surrounding context---which some look-behind or
look-ahead might have matched---could have been dropped if it wasn't
part of the set of matching lines. Therefore, when the printer re-runs
the regex engine in some cases (to do replacements, color matches, etc
etc), it won't be guaranteed to see the same matches that the searcher
found.
Overall, this is a giant clusterfuck and suggests that the way I divided
the abstraction boundary between the printer and the searcher is just
wrong. It's likely that the searcher needs to handle more of the work of
matching and pass that info on to the printer. The tricky part is that
this additional work isn't always needed. Ultimately, this means a
serious re-design of the interface between searching and printing. Sigh.
The way this fix works is to smuggle the underlying buffer used by the
searcher through into the printer. Since these bugs only impact
multi-line search (otherwise, searches are only limited to matches
across a single line), and since multi-line search always requires
having the entire file contents in a single contiguous slice (memory
mapped or on the heap), it follows that the buffer we pass through when
we need it is, in fact, the entire haystack. So this commit refactors
the printer's regex searching to use that buffer instead of the intended
bundle of bytes containing just the relevant matching portions of that
same buffer.
There is one last little hiccup: PCRE2 doesn't seem to have a way to
specify an ending position for a search. So when we re-run the search to
find matches, we can't say, "but don't search past here." Since the
buffer is likely to contain the entire file, we really cannot do
anything here other than specify a fixed upper bound on the number of
bytes to search. So if look-ahead goes more than N bytes beyond the
match, this code will break by simply being unable to find the match. In
practice, this is probably pretty rare. I believe that if we did a
better fix for this bug by fixing the interfaces, then we'd probably try
to have PCRE2 find the pertinent matches up front so that it never needs
to re-discover them.
Fixes#1412
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.
