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// 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.
extern crate rand;
use std::env;
use std::io::{self, Error, ErrorKind};
use std::fs;
use std::path::{self, PathBuf, AsPath};
use self::rand::{thread_rng, Rng};
/// A wrapper for a path to temporary directory implementing automatic
/// scope-based deletion.
pub struct TempDir {
path: Option<PathBuf>,
}
// How many times should we (re)try finding an unused random name? It should be
// enough that an attacker will run out of luck before we run out of patience.
const NUM_RETRIES: u32 = 1 << 31;
// How many characters should we include in a random file name? It needs to
// be enough to dissuade an attacker from trying to preemptively create names
// of that length, but not so huge that we unnecessarily drain the random number
// generator of entropy.
const NUM_RAND_CHARS: usize = 12;
impl TempDir {
/// Attempts to make a temporary directory inside of `tmpdir` whose name
/// will have the prefix `prefix`. The directory will be automatically
/// deleted once the returned wrapper is destroyed.
///
/// If no directory can be created, `Err` is returned.
#[allow(deprecated)] // rand usage
pub fn new_in<P: AsPath + ?Sized>(tmpdir: &P, prefix: &str)
-> io::Result<TempDir> {
let tmpdir = tmpdir.as_path();
assert!(tmpdir.is_absolute());
let mut rng = thread_rng();
for _ in 0..NUM_RETRIES {
let suffix: String = rng.gen_ascii_chars().take(NUM_RAND_CHARS).collect();
let leaf = if prefix.len() > 0 {
format!("{}.{}", prefix, suffix)
} else {
// If we're given an empty string for a prefix, then creating a
// directory starting with "." would lead to it being
// semi-invisible on some systems.
suffix
};
let path = tmpdir.join(&leaf);
match fs::create_dir(&path) {
Ok(_) => return Ok(TempDir { path: Some(path) }),
Err(ref e) if e.kind() == ErrorKind::PathAlreadyExists => {}
Err(e) => return Err(e)
}
}
Err(Error::new(ErrorKind::PathAlreadyExists,
"too many temporary directories already exist",
None))
}
/// Attempts to make a temporary directory inside of `env::temp_dir()` whose
/// name will have the prefix `prefix`. The directory will be automatically
/// deleted once the returned wrapper is destroyed.
///
/// If no directory can be created, `Err` is returned.
#[allow(deprecated)]
pub fn new(prefix: &str) -> io::Result<TempDir> {
TempDir::new_in(&env::temp_dir(), prefix)
}
/// Access the wrapped `std::path::Path` to the temporary directory.
pub fn path(&self) -> &path::Path {
self.path.as_ref().unwrap()
}
fn cleanup_dir(&mut self) -> io::Result<()> {
match self.path {
Some(ref p) => fs::remove_dir_all(p),
None => Ok(())
}
}
}
impl Drop for TempDir {
fn drop(&mut self) {
let _ = self.cleanup_dir();
}
}
// the tests for this module need to change the path using change_dir,
// and this doesn't play nicely with other tests so these unit tests are located
// in src/test/run-pass/tempfile.rs
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