Tempfile V4

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
         rust-version:
           - nightly
           - stable
-          - "1.63"
+          - "1.84"
         platform:
           - name: "Linux"
             os: ubuntu-latest

Cargo.toml

@@ -9,7 +9,7 @@ authors = [
 ]
 documentation = "https://docs.rs/tempfile"
 edition = "2021"
-rust-version = "1.63"
+rust-version = "1.84"
 homepage = "https://stebalien.com/projects/tempfile-rs/"
 keywords = ["tempfile", "tmpfile", "filesystem"]
 license = "MIT OR Apache-2.0"
@@ -18,8 +18,6 @@ description = "A library for managing temporary files and directories."
 
 [dependencies]
 fastrand = "2.1.1"
-# Not available in stdlib until 1.70, but we support 1.63 to support Debian stable.
-once_cell = { version = "1.19.0", default-features = false, features = ["std"] }
 
 [target.'cfg(any(unix, windows, target_os = "wasi"))'.dependencies]
 getrandom = { version = "0.3.0", default-features = false, optional = true }

README.md

@@ -14,7 +14,7 @@ patterns and surprisingly difficult to implement securely).
 Usage
 -----
 
-Minimum required Rust version: 1.63.0
+Minimum required Rust version: 1.84.0
 
 Add this to your `Cargo.toml`:
 

src/dir/imp/unix.rs

@@ -12,9 +12,7 @@ pub fn create(
     #[cfg(not(target_os = "wasi"))]
     {
         use std::os::unix::fs::{DirBuilderExt, PermissionsExt};
-        if let Some(p) = permissions {
-            dir_options.mode(p.mode());
-        }
+        dir_options.mode(permissions.map(|p| p.mode()).unwrap_or(0o700));
     }
     dir_options
         .create(&path)

src/dir/mod.rs

@@ -382,13 +382,6 @@ impl TempDir {
         self.path.as_ref()
     }
 
-    /// Deprecated alias for [`TempDir::keep`].
-    #[must_use]
-    #[deprecated = "use TempDir::keep()"]
-    pub fn into_path(self) -> PathBuf {
-        self.keep()
-    }
-
     /// Persist the temporary directory to disk, returning the [`PathBuf`] where it is located.
     ///
     /// This consumes the [`TempDir`] without deleting directory on the filesystem, meaning that
@@ -483,7 +476,10 @@ impl TempDir {
     }
 }
 
-impl AsRef<Path> for TempDir {
+// NOTE: This is implemented on &TempDir, not TempDir, to prevent accidentally moving the TempDir
+// into a function that calls `as_ref()` before immediately dropping it (deleting the underlying
+// temporary directory).
+impl AsRef<Path> for &TempDir {
     fn as_ref(&self) -> &Path {
         self.path()
     }

src/env.rs

@@ -1,13 +1,20 @@
-use std::env;
+use std::ffi::{OsStr, OsString};
 use std::path::{Path, PathBuf};
+use std::sync::{LazyLock, OnceLock};
+use std::{env, io};
 
 #[cfg(doc)]
 use crate::{tempdir_in, tempfile_in, Builder};
 
-// Once rust 1.70 is wide-spread (Debian stable), we can use OnceLock from stdlib.
-use once_cell::sync::OnceCell as OnceLock;
-
+static ENV_TEMPDIR: LazyLock<Option<PathBuf>> =
+    // Only call env::temp_dir() on platforms known to not panic.
+    LazyLock::new(if cfg!(any(unix, windows, target_os = "hermit")) {
+            || Some(env::temp_dir())
+        } else {
+            || None
+        });
 static DEFAULT_TEMPDIR: OnceLock<PathBuf> = OnceLock::new();
+static DEFAULT_PREFIX: OnceLock<OsString> = OnceLock::new();
 
 /// Override the default temporary directory (defaults to [`std::env::temp_dir`]). This function
 /// changes the _global_ default temporary directory for the entire program and should not be called
@@ -18,34 +25,63 @@ static DEFAULT_TEMPDIR: OnceLock<PathBuf> = OnceLock::new();
 /// should instead use the `_in` variants of the various temporary file/directory constructors
 /// ([`tempdir_in`], [`tempfile_in`], the so-named functions on [`Builder`], etc.).
 ///
-/// Only the first call to this function will succeed. All further calls will fail with `Err(path)`
-/// where `path` is previously set default temporary directory override.
+/// Only the **first** call to this function will succeed and return `Ok(path)` where `path` is a
+/// static reference to the temporary directory. All further calls will fail with `Err(path)` where
+/// `path` is the previously set default temporary directory override.
 ///
 /// **NOTE:** This function does not check if the specified directory exists and/or is writable.
-pub fn override_temp_dir(path: &Path) -> Result<(), PathBuf> {
-    let mut we_set = false;
-    let val = DEFAULT_TEMPDIR.get_or_init(|| {
-        we_set = true;
-        path.to_path_buf()
-    });
-    if we_set {
-        Ok(())
-    } else {
-        Err(val.to_owned())
+pub fn override_temp_dir(path: impl Into<PathBuf>) -> Result<&'static Path, &'static Path> {
+    let mut path = Some(path.into());
+    let val = DEFAULT_TEMPDIR.get_or_init(|| path.take().unwrap());
+    match path {
+        Some(_) => Err(val),
+        None => Ok(val),
     }
 }
 
 /// Returns the default temporary directory, used for both temporary directories and files if no
 /// directory is explicitly specified.
 ///
-/// This function simply delegates to [`std::env::temp_dir`] unless the default temporary directory
-/// has been override by a call to [`override_temp_dir`].
+/// Unless the default temporary directory has been overridden by a call to [`override_temp_dir`],
+/// this function delegates to [`std::env::temp_dir`] (when supported by the platform). It returns
+/// an error on platforms with no default temporary directory (e.g., WASI/WASM) unless
+/// [`override_temp_dir`] has already been called to set the temporary directory.
+///
+/// **NOTE:**
 ///
-/// **NOTE:** This function does not check if the returned directory exists and/or is writable.
-pub fn temp_dir() -> PathBuf {
+/// 1. This function does not check if the returned directory exists and/or is writable.
+/// 2. This function caches the result of [`std::env::temp_dir`]. Any future changes to, e.g., the
+///    `TMPDIR` environment variable won't have any effect.
+pub fn temp_dir() -> io::Result<&'static Path> {
     DEFAULT_TEMPDIR
         .get()
-        .map(|p| p.to_owned())
-        // Don't cache this in case the user uses std::env::set to change the temporary directory.
-        .unwrap_or_else(env::temp_dir)
+        .or_else(|| ENV_TEMPDIR.as_ref())
+        .map(|a| &**a)
+        .ok_or_else(|| io::Error::other("no temporary directory configured"))
+}
+
+/// Override the default prefix for new temporary files (defaults to "tmp"). This function changes
+/// the _global_ default prefix used by the entire program and should only be used by the top-level
+/// application. It's recommended that the top-level application call this function to specify an
+/// application-specific prefix to make it easier to identify temporary files belonging to the
+/// application.
+///
+/// Only the **first** call to this function will succeed and return `Ok(prefix)` where `prefix` is
+/// a static reference to the default temporary file prefix. All further calls will fail with
+/// `Err(prefix)` where `prefix` is the previously set default temporary file prefix.
+pub fn override_default_prefix(
+    prefix: impl Into<OsString>,
+) -> Result<&'static OsStr, &'static OsStr> {
+    let mut prefix = Some(prefix.into());
+    let val = DEFAULT_PREFIX.get_or_init(|| prefix.take().unwrap());
+    match prefix {
+        Some(_) => Err(val),
+        None => Ok(val),
+    }
+}
+
+/// Returns the default prefix used for new temporary files if no prefix is explicitly specified via
+/// [`Builder::prefix`].
+pub fn default_prefix() -> &'static OsStr {
+    DEFAULT_PREFIX.get().map(|p| &**p).unwrap_or("tmp".as_ref())
 }

src/file/imp/unix.rs

@@ -72,7 +72,7 @@ pub fn create(dir: &Path) -> io::Result<File> {
 fn create_unix(dir: &Path) -> io::Result<File> {
     util::create_helper(
         dir,
-        OsStr::new(".tmp"),
+        crate::env::default_prefix(),
         OsStr::new(""),
         crate::NUM_RAND_CHARS,
         |path| create_unlinked(&path),

src/file/imp/windows.rs

@@ -42,7 +42,7 @@ pub fn create_named(
 pub fn create(dir: &Path) -> io::Result<File> {
     util::create_helper(
         dir,
-        OsStr::new(".tmp"),
+        crate::env::default_prefix(),
         OsStr::new(""),
         crate::NUM_RAND_CHARS,
         |path| {

src/file/mod.rs

@@ -49,7 +49,7 @@ mod imp;
 /// # Ok::<(), std::io::Error>(())
 /// ```
 pub fn tempfile() -> io::Result<File> {
-    tempfile_in(env::temp_dir())
+    tempfile_in(env::temp_dir()?)
 }
 
 /// Create a new temporary file in the specified directory. Also see [`tempfile`].
@@ -368,13 +368,13 @@ impl Deref for TempPath {
     }
 }
 
-impl AsRef<Path> for TempPath {
+impl AsRef<Path> for &TempPath {
     fn as_ref(&self) -> &Path {
         &self.path
     }
 }
 
-impl AsRef<OsStr> for TempPath {
+impl AsRef<OsStr> for &TempPath {
     fn as_ref(&self) -> &OsStr {
         self.path.as_os_str()
     }
@@ -458,7 +458,7 @@ impl<F> fmt::Debug for NamedTempFile<F> {
     }
 }
 
-impl<F> AsRef<Path> for NamedTempFile<F> {
+impl<F> AsRef<Path> for &NamedTempFile<F> {
     #[inline]
     fn as_ref(&self) -> &Path {
         self.path()
@@ -1021,12 +1021,19 @@ impl<F: Seek> Seek for NamedTempFile<F> {
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
         self.as_file_mut().seek(pos).with_err_path(|| self.path())
     }
+    fn rewind(&mut self) -> io::Result<()> {
+        self.as_file_mut().rewind().with_err_path(|| self.path())
+    }
 }
 
 impl Seek for &NamedTempFile<File> {
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
         self.as_file().seek(pos).with_err_path(|| self.path())
     }
+
+    fn rewind(&mut self) -> io::Result<()> {
+        self.as_file().rewind().with_err_path(|| self.path())
+    }
 }
 
 #[cfg(any(unix, target_os = "wasi"))]