fs: add new FileSystemError type

Author: phip1611

uefi/src/fs/file_system/error.rs

@@ -0,0 +1,93 @@
+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 FileSystemError {
+    /// Logical errors. See [`LogicError`].
+    Logic(LogicError),
+    /// IO (low-level UEFI-errors) errors. See [`FileSystemIOError`].
+    IO(FileSystemIOError),
+    /// 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 = "FileSystemIOError({},{})", context, path)]
+pub struct FileSystemIOError {
+    /// 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,
+}
+
+/// Logical errors when working with files.
+#[derive(Debug, Clone, Display, PartialEq, Eq)]
+pub enum LogicError {
+    /// The path exists but does not correspond to a directory when a directory
+    /// was expected.
+    NotADirectory(PathBuf),
+    /// The path exists but does not correspond to a file when a file was
+    /// expected.
+    NotAFile(PathBuf),
+}
+
+/// Enum that further specifies the context in that a [`FileSystemError`]
+/// 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,
+}
+
+impl From<PathError> for FileSystemError {
+    fn from(value: PathError) -> Self {
+        Self::Path(value)
+    }
+}
+
+#[cfg(feature = "unstable")]
+impl core::error::Error for FileSystemError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
+        match self {
+            FileSystemError::IO(err) => Some(err),
+            FileSystemError::Path(err) => Some(err),
+            FileSystemError::Utf8Encoding(err) => Some(err),
+            FileSystemError::Logic(err) => Some(err),
+        }
+    }
+}
+
+#[cfg(feature = "unstable")]
+impl core::error::Error for FileSystemIOError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
+        Some(&self.uefi_error)
+    }
+}
+
+#[cfg(feature = "unstable")]
+impl core::error::Error for LogicError {}

uefi/src/fs/file_system/mod.rs

@@ -1,3 +1,5 @@
+mod error;
 mod fs;
 
+pub use error::*;
 pub use fs::*;

uefi/src/fs/path/pathbuf.rs

@@ -7,7 +7,7 @@ use core::fmt::{Display, Formatter};
 /// [`CString16`] strings and [`SEPARATOR`] as separator.
 ///
 /// `/` is replaced by [`SEPARATOR`] on the fly.
-#[derive(Debug, Default, Eq, PartialOrd, Ord)]
+#[derive(Clone, Debug, Default, Eq, PartialOrd, Ord)]
 pub struct PathBuf(CString16);
 
 impl PathBuf {