mirror of https://github.com/rust-lang/rust
94 lines
2.5 KiB
Rust
94 lines
2.5 KiB
Rust
//@ build-pass
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// Regression test for #20797.
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use std::default::Default;
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use std::io;
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use std::fs;
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use std::path::PathBuf;
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pub trait PathExtensions {
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fn is_dir(&self) -> bool { false }
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}
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impl PathExtensions for PathBuf {}
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/// A strategy for acquiring more subpaths to walk.
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pub trait Strategy {
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type P: PathExtensions;
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/// Gets additional subpaths from a given path.
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fn get_more(&self, item: &Self::P) -> io::Result<Vec<Self::P>>;
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/// Determine whether a path should be walked further.
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/// This is run against each item from `get_more()`.
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fn prune(&self, p: &Self::P) -> bool;
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}
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/// The basic fully-recursive strategy. Nothing is pruned.
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#[derive(Copy, Clone, Default)]
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pub struct Recursive;
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impl Strategy for Recursive {
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type P = PathBuf;
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fn get_more(&self, p: &PathBuf) -> io::Result<Vec<PathBuf>> {
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Ok(fs::read_dir(p).unwrap().map(|s| s.unwrap().path()).collect())
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}
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fn prune(&self, _: &PathBuf) -> bool { false }
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}
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/// A directory walker of `P` using strategy `S`.
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pub struct Subpaths<S: Strategy> {
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stack: Vec<S::P>,
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strategy: S,
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}
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impl<S: Strategy> Subpaths<S> {
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/// Creates a directory walker with a root path and strategy.
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pub fn new(p: &S::P, strategy: S) -> io::Result<Subpaths<S>> {
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let stack = strategy.get_more(p)?;
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Ok(Subpaths { stack: stack, strategy: strategy })
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}
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}
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impl<S: Default + Strategy> Subpaths<S> {
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/// Creates a directory walker with a root path and a default strategy.
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pub fn walk(p: &S::P) -> io::Result<Subpaths<S>> {
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Subpaths::new(p, Default::default())
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}
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}
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impl<S: Default + Strategy> Default for Subpaths<S> {
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fn default() -> Subpaths<S> {
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Subpaths { stack: Vec::new(), strategy: Default::default() }
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}
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}
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impl<S: Strategy> Iterator for Subpaths<S> {
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type Item = S::P;
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fn next (&mut self) -> Option<S::P> {
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let mut opt_path = self.stack.pop();
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while opt_path.is_some() && self.strategy.prune(opt_path.as_ref().unwrap()) {
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opt_path = self.stack.pop();
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}
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match opt_path {
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Some(path) => {
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if path.is_dir() {
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let result = self.strategy.get_more(&path);
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match result {
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Ok(dirs) => { self.stack.extend(dirs); },
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Err(..) => { }
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}
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}
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Some(path)
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}
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None => None,
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}
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}
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}
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fn _foo() {
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let _walker: Subpaths<Recursive> = Subpaths::walk(&PathBuf::from("/home")).unwrap();
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}
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fn main() {}
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