When running ripgrep like this:
rg foo > output
we must be careful not to search `output` since ripgrep is actively writing
to it. Searching it can cause massive blowups where the file grows without
bound.
While this is conceptually easy to fix (check the inode of the redirection
and the inode of the file you're about to search), there are a few problems
with it.
First, inodes are a Unix thing, so we need a Windows specific solution to
this as well. To resolve this concern, I created a new crate, `same-file`,
which provides a cross platform abstraction.
Second, stat'ing every file is costly. This is not avoidable on Windows,
but on Unix, we can get the inode number directly from directory traversal.
However, this information wasn't exposed, but now it is (through both the
ignore and walkdir crates).
Fixes#286
This adds a new walk type in the `ignore` crate, `WalkParallel`, which
provides a way for recursively iterating over a set of paths in parallel
while respecting various ignore rules.
The API is a bit strange, as a closure producing a closure isn't
something one often sees, but it does seem to work well.
This also allowed us to simplify much of the worker logic in ripgrep
proper, where MultiWorker is now gone.
This PR introduces a new sub-crate, `ignore`, which primarily provides a
fast recursive directory iterator that respects ignore files like
gitignore and other configurable filtering rules based on globs or even
file types.
This results in a substantial source of complexity moved out of ripgrep's
core and into a reusable component that others can now (hopefully)
benefit from.
While much of the ignore code carried over from ripgrep's core, a
substantial portion of it was rewritten with the following goals in
mind:
1. Reuse matchers built from gitignore files across directory iteration.
2. Design the matcher data structure to be amenable for parallelizing
directory iteration. (Indeed, writing the parallel iterator is the
next step.)
Fixes#9, #44, #45
