tempfile/
env.rs

1use std::env;
2use std::path::{Path, PathBuf};
3
4#[cfg(doc)]
5use crate::{tempdir_in, tempfile_in, Builder};
6
7// Once rust 1.70 is wide-spread (Debian stable), we can use OnceLock from stdlib.
8use once_cell::sync::OnceCell as OnceLock;
9
10static DEFAULT_TEMPDIR: OnceLock<PathBuf> = OnceLock::new();
11
12/// Override the default temporary directory (defaults to [`std::env::temp_dir`]). This function
13/// changes the _global_ default temporary directory for the entire program and should not be called
14/// except in exceptional cases where it's not configured correctly by the platform. Applications
15/// should first check if the path returned by [`env::temp_dir`] is acceptable.
16///
17/// If you're writing a library and want to control where your temporary files are placed, you
18/// should instead use the `_in` variants of the various temporary file/directory constructors
19/// ([`tempdir_in`], [`tempfile_in`], the so-named functions on [`Builder`], etc.).
20///
21/// Only the first call to this function will succeed. All further calls will fail with `Err(path)`
22/// where `path` is previously set default temporary directory override.
23///
24/// **NOTE:** This function does not check if the specified directory exists and/or is writable.
25pub fn override_temp_dir(path: &Path) -> Result<(), PathBuf> {
26    let mut we_set = false;
27    let val = DEFAULT_TEMPDIR.get_or_init(|| {
28        we_set = true;
29        path.to_path_buf()
30    });
31    if we_set {
32        Ok(())
33    } else {
34        Err(val.to_owned())
35    }
36}
37
38/// Returns the default temporary directory, used for both temporary directories and files if no
39/// directory is explicitly specified.
40///
41/// This function simply delegates to [`std::env::temp_dir`] unless the default temporary directory
42/// has been override by a call to [`override_temp_dir`].
43///
44/// **NOTE:** This function does not check if the returned directory exists and/or is writable.
45pub fn temp_dir() -> PathBuf {
46    DEFAULT_TEMPDIR
47        .get()
48        .map(|p| p.to_owned())
49        // Don't cache this in case the user uses std::env::set to change the temporary directory.
50        .unwrap_or_else(env::temp_dir)
51}
tempfile/env.rs

tempfile/
env.rs
