Tempfile V4

.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
         rust-version:
           - nightly
           - stable
-          - "1.63"
+          - "1.84"
         os:
           - ubuntu-latest
           - windows-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

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::ffi::OsStr;
 use std::fs::remove_dir_all;
 use std::mem;
 use std::path::{self, Path, PathBuf};
@@ -268,8 +267,8 @@ impl TempDir {
     /// assert!(tmp_name.starts_with("foo-"));
     /// # Ok::<(), std::io::Error>(())
     /// ```
-    pub fn with_prefix<S: AsRef<OsStr>>(prefix: S) -> io::Result<TempDir> {
-        Builder::new().prefix(&prefix).tempdir()
+    pub fn with_prefix(prefix: &str) -> io::Result<TempDir> {
+        Builder::new().prefix(prefix).tempdir()
     }
 
     /// Attempts to make a temporary directory with the specified suffix inside of
@@ -293,8 +292,8 @@ impl TempDir {
     /// assert!(tmp_name.ends_with("-foo"));
     /// # Ok::<(), std::io::Error>(())
     /// ```
-    pub fn with_suffix<S: AsRef<OsStr>>(suffix: S) -> io::Result<TempDir> {
-        Builder::new().suffix(&suffix).tempdir()
+    pub fn with_suffix(suffix: &str) -> io::Result<TempDir> {
+        Builder::new().suffix(suffix).tempdir()
     }
     /// Attempts to make a temporary directory with the specified prefix inside
     /// the specified directory. The directory and everything inside it will be
@@ -317,11 +316,8 @@ impl TempDir {
     /// assert!(tmp_name.ends_with("-foo"));
     /// # Ok::<(), std::io::Error>(())
     /// ```
-    pub fn with_suffix_in<S: AsRef<OsStr>, P: AsRef<Path>>(
-        suffix: S,
-        dir: P,
-    ) -> io::Result<TempDir> {
-        Builder::new().suffix(&suffix).tempdir_in(dir)
+    pub fn with_suffix_in<P: AsRef<Path>>(suffix: &str, dir: P) -> io::Result<TempDir> {
+        Builder::new().suffix(suffix).tempdir_in(dir)
     }
 
     /// Attempts to make a temporary directory with the specified prefix inside
@@ -345,11 +341,8 @@ impl TempDir {
     /// assert!(tmp_name.starts_with("foo-"));
     /// # Ok::<(), std::io::Error>(())
     /// ```
-    pub fn with_prefix_in<S: AsRef<OsStr>, P: AsRef<Path>>(
-        prefix: S,
-        dir: P,
-    ) -> io::Result<TempDir> {
-        Builder::new().prefix(&prefix).tempdir_in(dir)
+    pub fn with_prefix_in<P: AsRef<Path>>(prefix: &str, dir: P) -> io::Result<TempDir> {
+        Builder::new().prefix(prefix).tempdir_in(dir)
     }
 
     /// Accesses the [`Path`] to the temporary directory.
@@ -467,7 +460,10 @@ 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

@@ -1,30 +1,30 @@
 use std::env;
 use std::path::{Path, PathBuf};
+use std::sync::{LazyLock, OnceLock};
 
-// Once rust 1.70 is wide-spread (Debian stable), we can use OnceLock from stdlib.
-use once_cell::sync::OnceCell as OnceLock;
+#[cfg(doc)]
+use crate::Builder;
 
+static ENV_TEMPDIR: LazyLock<PathBuf> = LazyLock::new(env::temp_dir);
 static DEFAULT_TEMPDIR: OnceLock<PathBuf> = OnceLock::new();
+static DEFAULT_PREFIX: OnceLock<String> = 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
 /// except in exceptional cases where it's not configured correctly by the platform. Applications
 /// should first check if the path returned by [`env::temp_dir`] is acceptable.
 ///
-/// 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),
     }
 }
 
@@ -34,11 +34,35 @@ pub fn override_temp_dir(path: &Path) -> Result<(), PathBuf> {
 /// This function simply delegates to [`std::env::temp_dir`] unless the default temporary directory
 /// has been override by a call to [`override_temp_dir`].
 ///
-/// **NOTE:** This function does check if the returned directory exists and/or is writable.
-pub fn temp_dir() -> PathBuf {
-    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)
+/// **NOTE:**
+///
+/// 1. This function does 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() -> &'static Path {
+    DEFAULT_TEMPDIR.get().unwrap_or_else(|| &ENV_TEMPDIR)
+}
+
+/// 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<String>) -> Result<&'static str, &'static str> {
+    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 str {
+    DEFAULT_PREFIX.get().map(|p| &**p).unwrap_or("tmp".as_ref())
 }

src/file/imp/unix.rs

@@ -1,4 +1,3 @@
-use std::ffi::OsStr;
 use std::fs::{self, File, OpenOptions};
 use std::io;
 
@@ -72,8 +71,8 @@ pub fn create(dir: &Path) -> io::Result<File> {
 fn create_unix(dir: &Path) -> io::Result<File> {
     util::create_helper(
         dir,
-        OsStr::new(".tmp"),
-        OsStr::new(""),
+        crate::env::default_prefix(),
+        "",
         crate::NUM_RAND_CHARS,
         |path| create_unlinked(&path),
     )

src/file/imp/windows.rs

@@ -1,4 +1,3 @@
-use std::ffi::OsStr;
 use std::fs::{File, OpenOptions};
 use std::os::windows::ffi::OsStrExt;
 use std::os::windows::fs::OpenOptionsExt;
@@ -63,8 +62,8 @@ pub fn create_named(
 pub fn create(dir: &Path) -> io::Result<File> {
     util::create_helper(
         dir,
-        OsStr::new(".tmp"),
-        OsStr::new(""),
+        crate::env::default_prefix(),
+        "",
         crate::NUM_RAND_CHARS,
         |path| {
             let f = OpenOptions::new()

src/file/mod.rs

@@ -355,13 +355,13 @@ 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()
     }
@@ -445,7 +445,7 @@ 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()
@@ -567,8 +567,8 @@ impl NamedTempFile<File> {
     /// See [`NamedTempFile::new()`] for details.
     ///
     /// [`NamedTempFile::new()`]: #method.new
-    pub fn with_suffix<S: AsRef<OsStr>>(suffix: S) -> io::Result<NamedTempFile> {
-        Builder::new().suffix(&suffix).tempfile()
+    pub fn with_suffix(suffix: &str) -> io::Result<NamedTempFile> {
+        Builder::new().suffix(suffix).tempfile()
     }
     /// Create a new named temporary file with the specified filename suffix,
     /// in the specified directory.
@@ -582,20 +582,17 @@ impl NamedTempFile<File> {
     /// See [`NamedTempFile::new()`] for details.
     ///
     /// [`NamedTempFile::new()`]: #method.new
-    pub fn with_suffix_in<S: AsRef<OsStr>, P: AsRef<Path>>(
-        suffix: S,
-        dir: P,
-    ) -> io::Result<NamedTempFile> {
-        Builder::new().suffix(&suffix).tempfile_in(dir)
+    pub fn with_suffix_in<P: AsRef<Path>>(suffix: &str, dir: P) -> io::Result<NamedTempFile> {
+        Builder::new().suffix(suffix).tempfile_in(dir)
     }
 
     /// Create a new named temporary file with the specified filename prefix.
     ///
     /// See [`NamedTempFile::new()`] for details.
     ///
     /// [`NamedTempFile::new()`]: #method.new
-    pub fn with_prefix<S: AsRef<OsStr>>(prefix: S) -> io::Result<NamedTempFile> {
-        Builder::new().prefix(&prefix).tempfile()
+    pub fn with_prefix(prefix: &str) -> io::Result<NamedTempFile> {
+        Builder::new().prefix(prefix).tempfile()
     }
     /// Create a new named temporary file with the specified filename prefix,
     /// in the specified directory.
@@ -609,11 +606,8 @@ impl NamedTempFile<File> {
     /// See [`NamedTempFile::new()`] for details.
     ///
     /// [`NamedTempFile::new()`]: #method.new
-    pub fn with_prefix_in<S: AsRef<OsStr>, P: AsRef<Path>>(
-        prefix: S,
-        dir: P,
-    ) -> io::Result<NamedTempFile> {
-        Builder::new().prefix(&prefix).tempfile_in(dir)
+    pub fn with_prefix_in<P: AsRef<Path>>(prefix: &str, dir: P) -> io::Result<NamedTempFile> {
+        Builder::new().prefix(prefix).tempfile_in(dir)
     }
 }
 
@@ -998,12 +992,19 @@ 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"))]