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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
commit | 0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch) | |
tree | a31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /third_party/rust/walkdir/README.md | |
parent | Initial commit. (diff) | |
download | firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip |
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/walkdir/README.md')
-rw-r--r-- | third_party/rust/walkdir/README.md | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/third_party/rust/walkdir/README.md b/third_party/rust/walkdir/README.md new file mode 100644 index 0000000000..14bd4a9d26 --- /dev/null +++ b/third_party/rust/walkdir/README.md @@ -0,0 +1,139 @@ +walkdir +======= +A cross platform Rust library for efficiently walking a directory recursively. +Comes with support for following symbolic links, controlling the number of +open file descriptors and efficient mechanisms for pruning the entries in the +directory tree. + +[![Build status](https://github.com/BurntSushi/walkdir/workflows/ci/badge.svg)](https://github.com/BurntSushi/walkdir/actions) +[![](https://meritbadge.herokuapp.com/walkdir)](https://crates.io/crates/walkdir) + +Dual-licensed under MIT or the [UNLICENSE](https://unlicense.org/). + +### Documentation + +[docs.rs/walkdir](https://docs.rs/walkdir/) + +### Usage + +To use this crate, add `walkdir` as a dependency to your project's +`Cargo.toml`: + +```toml +[dependencies] +walkdir = "2" +``` + +### Example + +The following code recursively iterates over the directory given and prints +the path for each entry: + +```rust,no_run +use walkdir::WalkDir; + +for entry in WalkDir::new("foo") { + let entry = entry.unwrap(); + println!("{}", entry.path().display()); +} +``` + +Or, if you'd like to iterate over all entries and ignore any errors that may +arise, use `filter_map`. (e.g., This code below will silently skip directories +that the owner of the running process does not have permission to access.) + +```rust,no_run +use walkdir::WalkDir; + +for entry in WalkDir::new("foo").into_iter().filter_map(|e| e.ok()) { + println!("{}", entry.path().display()); +} +``` + +### Example: follow symbolic links + +The same code as above, except `follow_links` is enabled: + +```rust,no_run +use walkdir::WalkDir; + +for entry in WalkDir::new("foo").follow_links(true) { + let entry = entry.unwrap(); + println!("{}", entry.path().display()); +} +``` + +### Example: skip hidden files and directories efficiently on unix + +This uses the `filter_entry` iterator adapter to avoid yielding hidden files +and directories efficiently: + +```rust,no_run +use walkdir::{DirEntry, WalkDir}; + +fn is_hidden(entry: &DirEntry) -> bool { + entry.file_name() + .to_str() + .map(|s| s.starts_with(".")) + .unwrap_or(false) +} + +let walker = WalkDir::new("foo").into_iter(); +for entry in walker.filter_entry(|e| !is_hidden(e)) { + let entry = entry.unwrap(); + println!("{}", entry.path().display()); +} +``` + +### Minimum Rust version policy + +This crate's minimum supported `rustc` version is `1.34.0`. + +The current policy is that the minimum Rust version required to use this crate +can be increased in minor version updates. For example, if `crate 1.0` requires +Rust 1.20.0, then `crate 1.0.z` for all values of `z` will also require Rust +1.20.0 or newer. However, `crate 1.y` for `y > 0` may require a newer minimum +version of Rust. + +In general, this crate will be conservative with respect to the minimum +supported version of Rust. + +### Performance + +The short story is that performance is comparable with `find` and glibc's +`nftw` on both a warm and cold file cache. In fact, I cannot observe any +performance difference after running `find /`, `walkdir /` and `nftw /` on my +local file system (SSD, ~3 million entries). More precisely, I am reasonably +confident that this crate makes as few system calls and close to as few +allocations as possible. + +I haven't recorded any benchmarks, but here are some things you can try with a +local checkout of `walkdir`: + +```sh +# The directory you want to recursively walk: +DIR=$HOME + +# If you want to observe perf on a cold file cache, run this before *each* +# command: +sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches' + +# To warm the caches +find $DIR + +# Test speed of `find` on warm cache: +time find $DIR + +# Compile and test speed of `walkdir` crate: +cargo build --release --example walkdir +time ./target/release/examples/walkdir $DIR + +# Compile and test speed of glibc's `nftw`: +gcc -O3 -o nftw ./compare/nftw.c +time ./nftw $DIR + +# For shits and giggles, test speed of Python's (2 or 3) os.walk: +time python ./compare/walk.py $DIR +``` + +On my system, the performance of `walkdir`, `find` and `nftw` is comparable. |