Rollup merge of rust-lang#138832 - ChrisDenton:with_native_path, r=joboet

Start using `with_native_path` in `std::sys::fs`

Ideally, each platform should use their own native path type internally. This will, for example, allow passing a `CStr` directly to `std::fs::File::open` and therefore avoid the need for allocating a new null-terminated C string.

However, doing that for every function and platform all at once makes for a large PR that is way too prone to breaking. So this PR does some minimal refactoring which should help progress towards that goal. The changes are Unix-only and even then I avoided functions that require more changes so that this PR is just moving things around.

r? joboet

Author: jhpratt

library/std/src/fs.rs

@@ -2370,7 +2370,7 @@ impl AsInner<fs_imp::DirEntry> for DirEntry {
 #[doc(alias = "rm", alias = "unlink", alias = "DeleteFile")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn remove_file<P: AsRef<Path>>(path: P) -> io::Result<()> {
-    fs_imp::unlink(path.as_ref())
+    fs_imp::remove_file(path.as_ref())
 }
 
 /// Given a path, queries the file system to get information about a file,
@@ -2409,7 +2409,7 @@ pub fn remove_file<P: AsRef<Path>>(path: P) -> io::Result<()> {
 #[doc(alias = "stat")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
-    fs_imp::stat(path.as_ref()).map(Metadata)
+    fs_imp::metadata(path.as_ref()).map(Metadata)
 }
 
 /// Queries the metadata about a file without following symlinks.
@@ -2444,7 +2444,7 @@ pub fn metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
 #[doc(alias = "lstat")]
 #[stable(feature = "symlink_metadata", since = "1.1.0")]
 pub fn symlink_metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
-    fs_imp::lstat(path.as_ref()).map(Metadata)
+    fs_imp::symlink_metadata(path.as_ref()).map(Metadata)
 }
 
 /// Renames a file or directory to a new name, replacing the original file if
@@ -2598,7 +2598,7 @@ pub fn copy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<u64> {
 #[doc(alias = "CreateHardLink", alias = "linkat")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn hard_link<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
-    fs_imp::link(original.as_ref(), link.as_ref())
+    fs_imp::hard_link(original.as_ref(), link.as_ref())
 }
 
 /// Creates a new symbolic link on the filesystem.
@@ -2664,7 +2664,7 @@ pub fn soft_link<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Re
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn read_link<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
-    fs_imp::readlink(path.as_ref())
+    fs_imp::read_link(path.as_ref())
 }
 
 /// Returns the canonical, absolute form of a path with all intermediate
@@ -2840,7 +2840,7 @@ pub fn create_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
 #[doc(alias = "rmdir", alias = "RemoveDirectory")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
-    fs_imp::rmdir(path.as_ref())
+    fs_imp::remove_dir(path.as_ref())
 }
 
 /// Removes a directory at this path, after removing all its contents. Use
@@ -2967,7 +2967,7 @@ pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
 #[doc(alias = "ls", alias = "opendir", alias = "FindFirstFile", alias = "FindNextFile")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn read_dir<P: AsRef<Path>>(path: P) -> io::Result<ReadDir> {
-    fs_imp::readdir(path.as_ref()).map(ReadDir)
+    fs_imp::read_dir(path.as_ref()).map(ReadDir)
 }
 
 /// Changes the permissions found on a file or a directory.
@@ -3003,7 +3003,7 @@ pub fn read_dir<P: AsRef<Path>>(path: P) -> io::Result<ReadDir> {
 #[doc(alias = "chmod", alias = "SetFileAttributes")]
 #[stable(feature = "set_permissions", since = "1.1.0")]
 pub fn set_permissions<P: AsRef<Path>>(path: P, perm: Permissions) -> io::Result<()> {
-    fs_imp::set_perm(path.as_ref(), perm.0)
+    fs_imp::set_permissions(path.as_ref(), perm.0)
 }
 
 impl DirBuilder {

library/std/src/sys/fs/mod.rs

@@ -1,28 +1,113 @@
 #![deny(unsafe_op_in_unsafe_fn)]
 
+use crate::io;
+use crate::path::{Path, PathBuf};
+
 pub mod common;
 
 cfg_if::cfg_if! {
     if #[cfg(target_family = "unix")] {
         mod unix;
-        pub use unix::*;
+        use unix as imp;
+        pub use unix::{chown, fchown, lchown, chroot};
+        pub(crate) use unix::debug_assert_fd_is_open;
+        #[cfg(any(target_os = "linux", target_os = "android"))]
+        pub(crate) use unix::CachedFileMetadata;
+        use crate::sys::common::small_c_string::run_path_with_cstr as with_native_path;
     } else if #[cfg(target_os = "windows")] {
         mod windows;
-        pub use windows::*;
+        use windows as imp;
+        pub use windows::{symlink_inner, junction_point};
     } else if #[cfg(target_os = "hermit")] {
         mod hermit;
-        pub use hermit::*;
+        use hermit as imp;
     } else if #[cfg(target_os = "solid_asp3")] {
         mod solid;
-        pub use solid::*;
+        use solid as imp;
     } else if #[cfg(target_os = "uefi")] {
         mod uefi;
-        pub use uefi::*;
+        use uefi as imp;
     } else if #[cfg(target_os = "wasi")] {
         mod wasi;
-        pub use wasi::*;
+        use wasi as imp;
     } else {
         mod unsupported;
-        pub use unsupported::*;
+        use unsupported as imp;
     }
 }
+
+// FIXME: Replace this with platform-specific path conversion functions.
+#[cfg(not(target_family = "unix"))]
+#[inline]
+pub fn with_native_path<T>(path: &Path, f: &dyn Fn(&Path) -> io::Result<T>) -> io::Result<T> {
+    f(path)
+}
+
+pub use imp::{
+    DirBuilder, DirEntry, File, FileAttr, FilePermissions, FileTimes, FileType, OpenOptions,
+    ReadDir,
+};
+
+pub fn read_dir(path: &Path) -> io::Result<ReadDir> {
+    // FIXME: use with_native_path
+    imp::readdir(path)
+}
+
+pub fn remove_file(path: &Path) -> io::Result<()> {
+    with_native_path(path, &imp::unlink)
+}
+
+pub fn rename(old: &Path, new: &Path) -> io::Result<()> {
+    with_native_path(old, &|old| with_native_path(new, &|new| imp::rename(old, new)))
+}
+
+pub fn remove_dir(path: &Path) -> io::Result<()> {
+    with_native_path(path, &imp::rmdir)
+}
+
+pub fn remove_dir_all(path: &Path) -> io::Result<()> {
+    // FIXME: use with_native_path
+    imp::remove_dir_all(path)
+}
+
+pub fn read_link(path: &Path) -> io::Result<PathBuf> {
+    with_native_path(path, &imp::readlink)
+}
+
+pub fn symlink(original: &Path, link: &Path) -> io::Result<()> {
+    with_native_path(original, &|original| {
+        with_native_path(link, &|link| imp::symlink(original, link))
+    })
+}
+
+pub fn hard_link(original: &Path, link: &Path) -> io::Result<()> {
+    with_native_path(original, &|original| {
+        with_native_path(link, &|link| imp::link(original, link))
+    })
+}
+
+pub fn metadata(path: &Path) -> io::Result<FileAttr> {
+    with_native_path(path, &imp::stat)
+}
+
+pub fn symlink_metadata(path: &Path) -> io::Result<FileAttr> {
+    with_native_path(path, &imp::lstat)
+}
+
+pub fn set_permissions(path: &Path, perm: FilePermissions) -> io::Result<()> {
+    with_native_path(path, &|path| imp::set_perm(path, perm.clone()))
+}
+
+pub fn canonicalize(path: &Path) -> io::Result<PathBuf> {
+    with_native_path(path, &imp::canonicalize)
+}
+
+pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
+    // FIXME: use with_native_path
+    imp::copy(from, to)
+}
+
+pub fn exists(path: &Path) -> io::Result<bool> {
+    // FIXME: use with_native_path
+    imp::exists(path)
+}