rust/src/test/run-pass/issue-20797.rs
2015-01-26 16:01:16 -08:00

95 lines
2.7 KiB
Rust

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// ignore-android
// ignore-windows
// Regression test for #20797.
use std::default::Default;
use std::old_io::IoResult;
use std::old_io::fs;
use std::old_io::fs::PathExtensions;
/// A strategy for acquiring more subpaths to walk.
pub trait Strategy {
type P: PathExtensions;
/// Get additional subpaths from a given path.
fn get_more(&self, item: &Self::P) -> IoResult<Vec<Self::P>>;
/// Determine whether a path should be walked further.
/// This is run against each item from `get_more()`.
fn prune(&self, p: &Self::P) -> bool;
}
/// The basic fully-recursive strategy. Nothing is pruned.
#[derive(Copy, Default)]
pub struct Recursive;
impl Strategy for Recursive {
type P = Path;
fn get_more(&self, p: &Path) -> IoResult<Vec<Path>> { fs::readdir(p) }
fn prune(&self, _: &Path) -> bool { false }
}
/// A directory walker of `P` using strategy `S`.
pub struct Subpaths<S: Strategy> {
stack: Vec<S::P>,
strategy: S,
}
impl<S: Strategy> Subpaths<S> {
/// Create a directory walker with a root path and strategy.
pub fn new(p: &S::P, strategy: S) -> IoResult<Subpaths<S>> {
let stack = try!(strategy.get_more(p));
Ok(Subpaths { stack: stack, strategy: strategy })
}
}
impl<S: Default + Strategy> Subpaths<S> {
/// Create a directory walker with a root path and a default strategy.
pub fn walk(p: &S::P) -> IoResult<Subpaths<S>> {
Subpaths::new(p, Default::default())
}
}
impl<S: Default + Strategy> Default for Subpaths<S> {
fn default() -> Subpaths<S> {
Subpaths { stack: Vec::new(), strategy: Default::default() }
}
}
impl<S: Strategy> Iterator for Subpaths<S> {
type Item = S::P;
fn next (&mut self) -> Option<S::P> {
let mut opt_path = self.stack.pop();
while opt_path.is_some() && self.strategy.prune(opt_path.as_ref().unwrap()) {
opt_path = self.stack.pop();
}
match opt_path {
Some(path) => {
if PathExtensions::is_dir(&path) {
let result = self.strategy.get_more(&path);
match result {
Ok(dirs) => { self.stack.extend(dirs.into_iter()); },
Err(..) => { }
}
}
Some(path)
}
None => None,
}
}
}
fn main() {
let mut walker: Subpaths<Recursive> = Subpaths::walk(&Path::new("/home")).unwrap();
}