fs: add new Error type + naming adjustments

Author: phip1611

uefi-test-runner/src/fs/mod.rs

@@ -2,14 +2,14 @@
 
 use alloc::string::{String, ToString};
 use alloc::vec::Vec;
-use uefi::cstr16;
-use uefi::fs::{FileSystem, FileSystemError, PathBuf};
+use uefi::fs::{FileSystem, FileSystemIOErrorContext, IoError, PathBuf};
 use uefi::proto::media::fs::SimpleFileSystem;
 use uefi::table::boot::ScopedProtocol;
+use uefi::{cstr16, fs, Status};
 
 /// Tests functionality from the `uefi::fs` module. This test relies on a
 /// working File System Protocol, which is tested at a dedicated place.
-pub fn test(sfs: ScopedProtocol<SimpleFileSystem>) -> Result<(), FileSystemError> {
+pub fn test(sfs: ScopedProtocol<SimpleFileSystem>) -> Result<(), fs::Error> {
     let mut fs = FileSystem::new(sfs);
 
     // test create dir
@@ -24,9 +24,14 @@ pub fn test(sfs: ScopedProtocol<SimpleFileSystem>) -> Result<(), FileSystemError
     let read = String::from_utf8(read).expect("Should be valid utf8");
     assert_eq!(read.as_str(), data_to_write);
 
-    // test copy from non-existent file
+    // test copy from non-existent file: does the error type work as expected?
     let err = fs.copy(cstr16!("not_found"), cstr16!("abc"));
-    assert!(matches!(err, Err(FileSystemError::OpenError { .. })));
+    let expected_err = fs::Error::Io(IoError {
+        path: PathBuf::from(cstr16!("not_found")),
+        context: FileSystemIOErrorContext::OpenError,
+        uefi_error: uefi::Error::new(Status::NOT_FOUND, ()),
+    });
+    assert_eq!(err, Err(expected_err));
 
     // test rename file + path buf replaces / with \
     fs.rename(
@@ -35,7 +40,7 @@ pub fn test(sfs: ScopedProtocol<SimpleFileSystem>) -> Result<(), FileSystemError
     )?;
     // file should not be available after rename
     let err = fs.read(cstr16!("foo_dir\\foo_cpy"));
-    assert!(matches!(err, Err(FileSystemError::OpenError { .. })));
+    assert!(err.is_err());
 
     // test read dir on a sub dir
     let entries = fs

uefi/src/fs/file_system/error.rs

@@ -0,0 +1,82 @@
+use crate::fs::{PathBuf, PathError};
+use alloc::string::FromUtf8Error;
+use core::fmt::Debug;
+use derive_more::Display;
+
+/// All errors that can happen when working with the [`FileSystem`].
+///
+/// [`FileSystem`]: super::FileSystem
+#[derive(Debug, Clone, Display, PartialEq, Eq)]
+pub enum Error {
+    /// IO (low-level UEFI-errors) errors. See [`IoError`].
+    Io(IoError),
+    /// Path-related errors. See [`PathError`].
+    Path(PathError),
+    /// Can't parse file content as UTF-8. See [`FromUtf8Error`].
+    Utf8Encoding(FromUtf8Error),
+}
+
+/// UEFI-error with context when working with the underlying UEFI file protocol.
+#[derive(Debug, Clone, Display, PartialEq, Eq)]
+#[display(fmt = "IoError({},{})", context, path)]
+pub struct IoError {
+    /// The path that led to the error.
+    pub path: PathBuf,
+    /// The context in which the path was used.
+    pub context: FileSystemIOErrorContext,
+    /// The underlying UEFI error.
+    pub uefi_error: crate::Error,
+}
+
+/// Enum that further specifies the context in that a [`Error`]
+/// occurred.
+#[derive(Debug, Clone, Display, PartialEq, Eq)]
+pub enum FileSystemIOErrorContext {
+    /// Can't delete the directory.
+    CantDeleteDirectory,
+    /// Can't delete the file.
+    CantDeleteFile,
+    /// Error flushing file.
+    FlushFailure,
+    /// Can't open the root directory of the underlying volume.
+    CantOpenVolume,
+    /// Error while reading the metadata of the file.
+    Metadata,
+    /// Could not open the given path. One possible reason is that the file does
+    /// not exist.
+    OpenError,
+    /// Error reading file.
+    ReadFailure,
+    /// Error writing bytes.
+    WriteFailure,
+    /// The path exists but does not correspond to a directory when a directory
+    /// was expected.
+    NotADirectory,
+    /// The path exists but does not correspond to a file when a file was
+    /// expected.
+    NotAFile,
+}
+
+impl From<PathError> for Error {
+    fn from(value: PathError) -> Self {
+        Self::Path(value)
+    }
+}
+
+#[cfg(feature = "unstable")]
+impl core::error::Error for Error {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
+        match self {
+            Error::Io(err) => Some(err),
+            Error::Path(err) => Some(err),
+            Error::Utf8Encoding(err) => Some(err),
+        }
+    }
+}
+
+#[cfg(feature = "unstable")]
+impl core::error::Error for IoError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
+        Some(&self.uefi_error)
+    }
+}