| use rand::distributions::Alphanumeric; |
| use rand::{self, Rng}; |
| use std::ffi::{OsStr, OsString}; |
| use std::path::{Path, PathBuf}; |
| use std::{io, str}; |
| |
| use crate::error::IoResultExt; |
| |
| fn tmpname(prefix: &OsStr, suffix: &OsStr, rand_len: usize) -> OsString { |
| let mut buf = OsString::with_capacity(prefix.len() + suffix.len() + rand_len); |
| buf.push(prefix); |
| |
| // Push each character in one-by-one. Unfortunately, this is the only |
| // safe(ish) simple way to do this without allocating a temporary |
| // String/Vec. |
| unsafe { |
| rand::thread_rng() |
| .sample_iter(&Alphanumeric) |
| .take(rand_len) |
| .for_each(|b| buf.push(str::from_utf8_unchecked(&[b as u8]))) |
| } |
| buf.push(suffix); |
| buf |
| } |
| |
| pub fn create_helper<F, R>( |
| base: &Path, |
| prefix: &OsStr, |
| suffix: &OsStr, |
| random_len: usize, |
| f: F, |
| ) -> io::Result<R> |
| where |
| F: Fn(PathBuf) -> io::Result<R>, |
| { |
| let num_retries = if random_len != 0 { crate::NUM_RETRIES } else { 1 }; |
| |
| for _ in 0..num_retries { |
| let path = base.join(tmpname(prefix, suffix, random_len)); |
| return match f(path) { |
| Err(ref e) if e.kind() == io::ErrorKind::AlreadyExists => continue, |
| res => res, |
| }; |
| } |
| |
| Err(io::Error::new( |
| io::ErrorKind::AlreadyExists, |
| "too many temporary files exist", |
| )) |
| .with_err_path(|| base) |
| } |