Rollup merge of rust-lang#138269 - Ayush1325:uefi-fs-permission, r=joboet

uefi: fs: Implement FileType, FilePermissions and FileAttr

- In UEFI, both FileType and FilePermissions are represented by the attr bitfield.
- Using simple bools here since both are represented by a single bit.
- Add `FILE_PERMISSION` mask for constructing attribute while change permissions.

cc `@nicholasbishop`

Author: jieyouxu

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

@@ -1,14 +1,21 @@
 use crate::ffi::OsString;
 use crate::fmt;
-use crate::hash::{Hash, Hasher};
+use crate::hash::Hash;
 use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut, SeekFrom};
 use crate::path::{Path, PathBuf};
 use crate::sys::time::SystemTime;
 use crate::sys::unsupported;
 
+#[expect(dead_code)]
+const FILE_PERMISSIONS_MASK: u64 = r_efi::protocols::file::READ_ONLY;
+
 pub struct File(!);
 
-pub struct FileAttr(!);
+#[derive(Clone)]
+pub struct FileAttr {
+    attr: u64,
+    size: u64,
+}
 
 pub struct ReadDir(!);
 
@@ -20,42 +27,40 @@ pub struct OpenOptions {}
 #[derive(Copy, Clone, Debug, Default)]
 pub struct FileTimes {}
 
-pub struct FilePermissions(!);
+#[derive(Clone, PartialEq, Eq, Debug)]
+// Bool indicates if file is readonly
+pub struct FilePermissions(bool);
 
-pub struct FileType(!);
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+// Bool indicates if directory
+pub struct FileType(bool);
 
 #[derive(Debug)]
 pub struct DirBuilder {}
 
 impl FileAttr {
     pub fn size(&self) -> u64 {
-        self.0
+        self.size
     }
 
     pub fn perm(&self) -> FilePermissions {
-        self.0
+        FilePermissions::from_attr(self.attr)
     }
 
     pub fn file_type(&self) -> FileType {
-        self.0
+        FileType::from_attr(self.attr)
     }
 
     pub fn modified(&self) -> io::Result<SystemTime> {
-        self.0
+        unsupported()
     }
 
     pub fn accessed(&self) -> io::Result<SystemTime> {
-        self.0
+        unsupported()
     }
 
     pub fn created(&self) -> io::Result<SystemTime> {
-        self.0
-    }
-}
-
-impl Clone for FileAttr {
-    fn clone(&self) -> FileAttr {
-        self.0
+        unsupported()
     }
 }
 
@@ -64,28 +69,17 @@ impl FilePermissions {
         self.0
     }
 
-    pub fn set_readonly(&mut self, _readonly: bool) {
-        self.0
+    pub fn set_readonly(&mut self, readonly: bool) {
+        self.0 = readonly
     }
-}
 
-impl Clone for FilePermissions {
-    fn clone(&self) -> FilePermissions {
-        self.0
+    const fn from_attr(attr: u64) -> Self {
+        Self(attr & r_efi::protocols::file::READ_ONLY != 0)
     }
-}
-
-impl PartialEq for FilePermissions {
-    fn eq(&self, _other: &FilePermissions) -> bool {
-        self.0
-    }
-}
 
-impl Eq for FilePermissions {}
-
-impl fmt::Debug for FilePermissions {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0
+    #[expect(dead_code)]
+    const fn to_attr(&self) -> u64 {
+        if self.0 { r_efi::protocols::file::READ_ONLY } else { 0 }
     }
 }
 
@@ -100,39 +94,16 @@ impl FileType {
     }
 
     pub fn is_file(&self) -> bool {
-        self.0
+        !self.is_dir()
     }
 
+    // Symlinks are not supported in UEFI
     pub fn is_symlink(&self) -> bool {
-        self.0
-    }
-}
-
-impl Clone for FileType {
-    fn clone(&self) -> FileType {
-        self.0
+        false
     }
-}
-
-impl Copy for FileType {}
 
-impl PartialEq for FileType {
-    fn eq(&self, _other: &FileType) -> bool {
-        self.0
-    }
-}
-
-impl Eq for FileType {}
-
-impl Hash for FileType {
-    fn hash<H: Hasher>(&self, _h: &mut H) {
-        self.0
-    }
-}
-
-impl fmt::Debug for FileType {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0
+    const fn from_attr(attr: u64) -> Self {
+        Self(attr & r_efi::protocols::file::DIRECTORY != 0)
     }
 }
 
@@ -303,8 +274,8 @@ pub fn rename(_old: &Path, _new: &Path) -> io::Result<()> {
     unsupported()
 }
 
-pub fn set_perm(_p: &Path, perm: FilePermissions) -> io::Result<()> {
-    match perm.0 {}
+pub fn set_perm(_p: &Path, _perm: FilePermissions) -> io::Result<()> {
+    unsupported()
 }
 
 pub fn rmdir(_p: &Path) -> io::Result<()> {