add DirEntry API, fixes for other platforms

Author: Qelxiros

library/std/src/fs.rs

@@ -2734,6 +2734,178 @@ impl DirEntry {
     pub fn file_name(&self) -> OsString {
         self.0.file_name()
     }
+
+    /// Attempts to open the file represented by `self` in read-only mode.
+    ///
+    /// # Errors
+    ///
+    /// This function will error whenever [`File::open`] would error, including when `self`
+    /// represents a directory.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(dirfd)]
+    /// use std::{fs, io::read_to_string};
+    ///
+    /// if let Ok(entries) = fs::read_dir(".") {
+    ///     for entry in entries {
+    ///         if let Ok(entry) = entry {
+    ///             // Here, `entry` is a `DirEntry`.
+    ///             if let Ok(file) = entry.open_file() && let Ok(text) = read_to_string(file) {
+    ///                 println!("{}", text);
+    ///             }
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    #[unstable(feature = "dirfd", issue = "120426")]
+    pub fn open_file(&self) -> io::Result<File> {
+        self.0.open_file().map(|inner| File { inner })
+    }
+
+    /// Attempts to open the file represented by `self` with the options specified by `opts`.
+    ///
+    /// # Errors
+    ///
+    /// This function will error whenever [`OpenOptions::open`] would error, including when `self`
+    /// represents a directory.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(dirfd)]
+    /// use std::{fs, io::Write};
+    ///
+    /// if let Ok(entries) = fs::read_dir(".") {
+    ///     for entry in entries {
+    ///         if let Ok(entry) = entry {
+    ///             // Here, `entry` is a `DirEntry`.
+    ///             if let Ok(mut file) = entry.open_file_with(fs::OpenOptions::new().write(true)) {
+    ///                 let _ = file.write(b"foo");
+    ///             }
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    #[unstable(feature = "dirfd", issue = "120426")]
+    pub fn open_file_with(&self, opts: &OpenOptions) -> io::Result<File> {
+        self.0.open_file_with(&opts.0).map(|inner| File { inner })
+    }
+
+    /// Attempts to open the directory represented by `self` in read-only mode.
+    ///
+    /// # Errors
+    ///
+    /// This function will error whenever [`Dir::new`] would error, including when `self`
+    /// represents a file.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(dirfd)]
+    /// use std::{fs, io::read_to_string};
+    ///
+    /// if let Ok(entries) = fs::read_dir(".") {
+    ///     for entry in entries {
+    ///         if let Ok(entry) = entry {
+    ///             // Here, `entry` is a `DirEntry`.
+    ///             if let Ok(dir) = entry.open_dir() && let Ok(file) = dir.open("foo") && let Ok(text) = read_to_string(file) {
+    ///                 println!("{}", text);
+    ///             }
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    #[unstable(feature = "dirfd", issue = "120426")]
+    pub fn open_dir(&self) -> io::Result<Dir> {
+        self.0.open_dir().map(|inner| Dir { inner })
+    }
+
+    /// Attempts to open the directory represented by `self` with the options specified by `opts`.
+    ///
+    /// # Errors
+    ///
+    /// This function will error whenever [`Dir::new_with`] would error, including when `self`
+    /// represents a file.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(dirfd)]
+    /// use std::fs;
+    ///
+    /// if let Ok(entries) = fs::read_dir(".") {
+    ///     for entry in entries {
+    ///         if let Ok(entry) = entry {
+    ///             // Here, `entry` is a `DirEntry`.
+    ///             if let Ok(dir) = entry.open_dir_with(fs::OpenOptions::new().write(true)) {
+    ///                 let _ = dir.remove_file("foo");
+    ///             }
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    #[unstable(feature = "dirfd", issue = "120426")]
+    pub fn open_dir_with(&self, opts: &OpenOptions) -> io::Result<Dir> {
+        self.0.open_dir_with(&opts.0).map(|inner| Dir { inner })
+    }
+
+    /// Attempts to remove the file represented by `self`.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error whenever [`remove_file`] would error.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(dirfd)]
+    /// use std::fs;
+    ///
+    /// if let Ok(entries) = fs::read_dir(".") {
+    ///     for entry in entries {
+    ///         if let Ok(entry) = entry {
+    ///             // Here, `entry` is a `DirEntry`.
+    ///             if let Ok(ty) = entry.file_type() && ty.is_file() {
+    ///                 let _ = entry.remove_file();
+    ///             }
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    #[unstable(feature = "dirfd", issue = "120426")]
+    pub fn remove_file(&self) -> io::Result<()> {
+        self.0.remove_file()
+    }
+
+    /// Attempts to remove the directory represented by `self`.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error whenever [`remove_dir`] would error.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(dirfd)]
+    /// use std::fs;
+    ///
+    /// if let Ok(entries) = fs::read_dir(".") {
+    ///     for entry in entries {
+    ///         if let Ok(entry) = entry {
+    ///             // Here, `entry` is a `DirEntry`.
+    ///             if let Ok(ty) = entry.file_type() && ty.is_dir() {
+    ///                 let _ = entry.remove_dir();
+    ///             }
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    #[unstable(feature = "dirfd", issue = "120426")]
+    pub fn remove_dir(&self) -> io::Result<()> {
+        self.0.remove_dir()
+    }
 }
 
 #[stable(feature = "dir_entry_debug", since = "1.13.0")]

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

@@ -1,9 +1,10 @@
 #![allow(dead_code)] // not used on all platforms
 
 use crate::fmt;
-use crate::fs::{self, File, OpenOptions, create_dir, remove_dir, remove_file, rename};
+use crate::fs::{self, create_dir, remove_dir, remove_file, rename};
 use crate::io::{self, Error, ErrorKind};
 use crate::path::{Path, PathBuf};
+use crate::sys::fs::{File, OpenOptions};
 use crate::sys_common::ignore_notfound;
 
 pub(crate) const NOT_FILE_ERROR: Error = io::const_error!(
@@ -73,18 +74,32 @@ impl Dir {
         Ok(Self { path: path.as_ref().to_path_buf() })
     }
 
+    pub fn new_for_traversal<P: AsRef<Path>>(path: P) -> io::Result<Self> {
+        Ok(Self { path: path.as_ref().to_path_buf() })
+    }
+
     pub fn open<P: AsRef<Path>>(&self, path: P) -> io::Result<File> {
-        File::open(self.path.join(path))
+        let mut opts = OpenOptions::new();
+        opts.read(true);
+        File::open(&self.path.join(path), &opts)
     }
 
     pub fn open_with<P: AsRef<Path>>(&self, path: P, opts: &OpenOptions) -> io::Result<File> {
-        opts.open(self.path.join(path))
+        File::open(&self.path.join(path), opts)
     }
 
     pub fn create_dir<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
         create_dir(self.path.join(path))
     }
 
+    pub fn open_dir<P: AsRef<Path>>(&self, path: P) -> io::Result<Self> {
+        Self::new(self.path.join(path))
+    }
+
+    pub fn open_dir_with<P: AsRef<Path>>(&self, path: P, opts: &OpenOptions) -> io::Result<Self> {
+        Self::new_with(self.path.join(path), opts)
+    }
+
     pub fn remove_file<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
         remove_file(self.path.join(path))
     }

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

@@ -12,6 +12,7 @@ use crate::sync::Arc;
 use crate::sys::common::small_c_string::run_path_with_cstr;
 use crate::sys::fd::FileDesc;
 pub use crate::sys::fs::common::{Dir, copy, exists};
+use crate::sys::fs::{remove_dir, remove_file};
 use crate::sys::time::SystemTime;
 use crate::sys::{cvt, unsupported, unsupported_err};
 use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
@@ -252,6 +253,32 @@ impl DirEntry {
     pub fn file_name_os_str(&self) -> &OsStr {
         self.name.as_os_str()
     }
+
+    pub fn open_file(&self) -> io::Result<File> {
+        let mut opts = OpenOptions::new();
+        opts.read(true);
+        File::open(&self.path(), &opts)
+    }
+
+    pub fn open_file_with(&self, opts: &OpenOptions) -> io::Result<File> {
+        File::open(&self.path(), opts)
+    }
+
+    pub fn open_dir(&self) -> io::Result<Dir> {
+        Dir::new(self.path())
+    }
+
+    pub fn open_dir_with(&self, opts: &OpenOptions) -> io::Result<Dir> {
+        Dir::new_with(self.path(), opts)
+    }
+
+    pub fn remove_file(&self) -> io::Result<()> {
+        remove_file(&self.path())
+    }
+
+    pub fn remove_dir(&self) -> io::Result<()> {
+        remove_dir(&self.path())
+    }
 }
 
 impl OpenOptions {

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

@@ -10,6 +10,7 @@ use crate::os::solid::ffi::OsStrExt;
 use crate::path::{Path, PathBuf};
 use crate::sync::Arc;
 pub use crate::sys::fs::common::{Dir, exists};
+use crate::sys::fs::{remove_dir, remove_file};
 use crate::sys::pal::{abi, error};
 use crate::sys::time::SystemTime;
 use crate::sys::{unsupported, unsupported_err};
@@ -219,6 +220,32 @@ impl DirEntry {
             _ => lstat(&self.path()).map(|m| m.file_type()),
         }
     }
+
+    pub fn open_file(&self) -> io::Result<File> {
+        let mut opts = OpenOptions::new();
+        opts.read(true);
+        File::open(&self.path(), &opts)
+    }
+
+    pub fn open_file_with(&self, opts: &OpenOptions) -> io::Result<File> {
+        File::open(&self.path(), opts)
+    }
+
+    pub fn open_dir(&self) -> io::Result<Dir> {
+        Dir::new(self.path())
+    }
+
+    pub fn open_dir_with(&self, opts: &OpenOptions) -> io::Result<Dir> {
+        Dir::new_with(self.path(), opts)
+    }
+
+    pub fn remove_file(&self) -> io::Result<()> {
+        remove_file(&self.path())
+    }
+
+    pub fn remove_dir(&self) -> io::Result<()> {
+        remove_dir(&self.path())
+    }
 }
 
 impl OpenOptions {

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

@@ -126,6 +126,10 @@ impl Dir {
         unsupported()
     }
 
+    pub fn new_for_traversal<P: AsRef<Path>>(_path: P) -> io::Result<Self> {
+        unsupported()
+    }
+
     pub fn open<P: AsRef<Path>>(&self, _path: P) -> io::Result<File> {
         self.0
     }
@@ -138,6 +142,14 @@ impl Dir {
         self.0
     }
 
+    pub fn open_dir<P: AsRef<Path>>(&self, _path: P) -> io::Result<Self> {
+        self.0
+    }
+
+    pub fn open_dir_with<P: AsRef<Path>>(&self, _path: P, _opts: &OpenOptions) -> io::Result<Self> {
+        self.0
+    }
+
     pub fn remove_file<P: AsRef<Path>>(&self, _path: P) -> io::Result<()> {
         self.0
     }
@@ -192,6 +204,30 @@ impl DirEntry {
     pub fn file_type(&self) -> io::Result<FileType> {
         self.0
     }
+
+    pub fn open_file(&self) -> io::Result<File> {
+        self.0
+    }
+
+    pub fn open_file_with(&self, _opts: &OpenOptions) -> io::Result<File> {
+        self.0
+    }
+
+    pub fn open_dir(&self) -> io::Result<Dir> {
+        self.0
+    }
+
+    pub fn open_dir_with(&self, _opts: &OpenOptions) -> io::Result<Dir> {
+        self.0
+    }
+
+    pub fn remove_file(&self) -> io::Result<()> {
+        self.0
+    }
+
+    pub fn remove_dir(&self) -> io::Result<()> {
+        self.0
+    }
 }
 
 impl OpenOptions {