Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

vendor/tempfile/src/util.rs

@@ -0,0 +1,47 @@
+use std::ffi::{OsStr, OsString};
+use std::path::{Path, PathBuf};
+use std::{io, iter::repeat_with};
+
+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);
+    let mut char_buf = [0u8; 4];
+    for c in repeat_with(fastrand::alphanumeric).take(rand_len) {
+        buf.push(c.encode_utf8(&mut char_buf));
+    }
+    buf.push(suffix);
+    buf
+}
+
+pub fn create_helper<R>(
+    base: &Path,
+    prefix: &OsStr,
+    suffix: &OsStr,
+    random_len: usize,
+    mut f: impl FnMut(PathBuf) -> io::Result<R>,
+) -> 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 && num_retries > 1 => continue,
+            // AddrInUse can happen if we're creating a UNIX domain socket and
+            // the path already exists.
+            Err(ref e) if e.kind() == io::ErrorKind::AddrInUse && num_retries > 1 => continue,
+            res => res,
+        };
+    }
+
+    Err(io::Error::new(
+        io::ErrorKind::AlreadyExists,
+        "too many temporary files exist",
+    ))
+    .with_err_path(|| base)
+}