src/librustc_back/tempdir.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use std::env;
  12 use std::io::{self, Error, ErrorKind};
  13 use std::fs;
  14 use std::path::{self, PathBuf, Path};
  15 use std::__rand::{thread_rng, Rng};
  16
  17 /// A wrapper for a path to temporary directory implementing automatic
  18 /// scope-based deletion.
  19 pub struct TempDir {
  20     path: Option<PathBuf>,
  21 }
  22
  23 // How many times should we (re)try finding an unused random name? It should be
  24 // enough that an attacker will run out of luck before we run out of patience.
  25 const NUM_RETRIES: u32 = 1 << 31;
  26 // How many characters should we include in a random file name? It needs to
  27 // be enough to dissuade an attacker from trying to preemptively create names
  28 // of that length, but not so huge that we unnecessarily drain the random number
  29 // generator of entropy.
  30 const NUM_RAND_CHARS: usize = 12;
  31
  32 impl TempDir {
  33     /// Attempts to make a temporary directory inside of `tmpdir` whose name
  34     /// will have the prefix `prefix`. The directory will be automatically
  35     /// deleted once the returned wrapper is destroyed.
  36     ///
  37     /// If no directory can be created, `Err` is returned.
  38     #[allow(deprecated)] // rand usage
  39     pub fn new_in<P: AsRef<Path>>(tmpdir: P, prefix: &str)
  40                                   -> io::Result<TempDir> {
  41         Self::_new_in(tmpdir.as_ref(), prefix)
  42     }
  43
  44     fn _new_in(tmpdir: &Path, prefix: &str) -> io::Result<TempDir> {
  45         let storage;
  46         let mut tmpdir = tmpdir;
  47         if !tmpdir.is_absolute() {
  48             let cur_dir = env::current_dir()?;
  49             storage = cur_dir.join(tmpdir);
  50             tmpdir = &storage;
  51             // return TempDir::new_in(&cur_dir.join(tmpdir), prefix);
  52         }
  53
  54         let mut rng = thread_rng();
  55         for _ in 0..NUM_RETRIES {
  56             let suffix: String = rng.gen_ascii_chars().take(NUM_RAND_CHARS).collect();
  57             let leaf = if !prefix.is_empty() {
  58                 format!("{}.{}", prefix, suffix)
  59             } else {
  60                 // If we're given an empty string for a prefix, then creating a
  61                 // directory starting with "." would lead to it being
  62                 // semi-invisible on some systems.
  63                 suffix
  64             };
  65             let path = tmpdir.join(&leaf);
  66             match fs::create_dir(&path) {
  67                 Ok(_) => return Ok(TempDir { path: Some(path) }),
  68                 Err(ref e) if e.kind() == ErrorKind::AlreadyExists => {}
  69                 Err(e) => return Err(e)
  70             }
  71         }
  72
  73         Err(Error::new(ErrorKind::AlreadyExists,
  74                        "too many temporary directories already exist"))
  75     }
  76
  77     /// Attempts to make a temporary directory inside of `env::temp_dir()` whose
  78     /// name will have the prefix `prefix`. The directory will be automatically
  79     /// deleted once the returned wrapper is destroyed.
  80     ///
  81     /// If no directory can be created, `Err` is returned.
  82     pub fn new(prefix: &str) -> io::Result<TempDir> {
  83         TempDir::new_in(&env::temp_dir(), prefix)
  84     }
  85
  86     /// Unwrap the wrapped `std::path::Path` from the `TempDir` wrapper.
  87     /// This discards the wrapper so that the automatic deletion of the
  88     /// temporary directory is prevented.
  89     pub fn into_path(mut self) -> PathBuf {
  90         self.path.take().unwrap()
  91     }
  92
  93     /// Access the wrapped `std::path::Path` to the temporary directory.
  94     pub fn path(&self) -> &path::Path {
  95         self.path.as_ref().unwrap()
  96     }
  97
  98     /// Close and remove the temporary directory
  99     ///
 100     /// Although `TempDir` removes the directory on drop, in the destructor
 101     /// any errors are ignored. To detect errors cleaning up the temporary
 102     /// directory, call `close` instead.
 103     pub fn close(mut self) -> io::Result<()> {
 104         self.cleanup_dir()
 105     }
 106
 107     fn cleanup_dir(&mut self) -> io::Result<()> {
 108         match self.path {
 109             Some(ref p) => fs::remove_dir_all(p),
 110             None => Ok(())
 111         }
 112     }
 113 }
 114
 115 impl Drop for TempDir {
 116     fn drop(&mut self) {
 117         let _ = self.cleanup_dir();
 118     }
 119 }
 120
 121 // the tests for this module need to change the path using change_dir,
 122 // and this doesn't play nicely with other tests so these unit tests are located
 123 // in src/test/run-pass/tempfile.rs