Add typed errors to ImmutableFile functions

Author: Alenar

mithril-common/src/digesters/digester.rs

@@ -1,3 +1,4 @@
+use crate::digesters::immutable_file::ImmutableFileListingError;
 use crate::entities::ImmutableFileNumber;
 use std::io;
 use thiserror::Error;
@@ -13,8 +14,8 @@ pub struct DigesterResult {
 
 #[derive(Error, Debug)]
 pub enum DigesterError {
-    #[error("Immutable files listing failed: `{0}`")]
-    ListImmutablesError(String),
+    #[error("Immutable files listing failed")]
+    ListImmutablesError(#[from] ImmutableFileListingError),
 
     #[error("At least two immutables chunk should exists")]
     NotEnoughImmutable(),

mithril-common/src/digesters/immutable_digester.rs

@@ -48,8 +48,7 @@ impl ImmutableDigester {
 
 impl Digester for ImmutableDigester {
     fn compute_digest(&self) -> Result<DigesterResult, DigesterError> {
-        let immutables = ImmutableFile::list_completed_in_dir(&*self.db_directory)
-            .map_err(DigesterError::ListImmutablesError)?;
+        let immutables = ImmutableFile::list_completed_in_dir(&*self.db_directory)?;
         let last_immutable = immutables
             .last()
             .ok_or(DigesterError::NotEnoughImmutable())?;

mithril-common/src/digesters/immutable_file.rs

@@ -1,8 +1,10 @@
 use crate::entities::ImmutableFileNumber;
 
 use std::ffi::OsStr;
+use std::io;
+use std::num::ParseIntError;
 use std::path::{Path, PathBuf};
-
+use thiserror::Error;
 use walkdir::WalkDir;
 
 fn is_immutable(path: &Path) -> bool {
@@ -16,18 +18,33 @@ pub struct ImmutableFile {
     pub number: ImmutableFileNumber,
 }
 
+#[derive(Error, Debug)]
+pub enum ImmutableFileCreationError {
+    #[error("Couldn't extract the file stem for '{path:?}'")]
+    FileStemExtraction { path: PathBuf },
+    #[error("Couldn't extract the filename as string for '{path:?}'")]
+    FileNameExtraction { path: PathBuf },
+    #[error("Error while parsing immutable file number")]
+    FileNumberParsing(#[from] ParseIntError),
+}
+
+#[derive(Error, Debug)]
+pub enum ImmutableFileListingError {
+    #[error("metadata parsing failed")]
+    MetadataParsing(#[from] io::Error),
+    #[error("immutable file creation error")]
+    ImmutableFileCreation(#[from] ImmutableFileCreationError),
+}
+
 impl ImmutableFile {
-    pub fn new(path: PathBuf) -> Result<Self, String> {
+    pub fn new(path: PathBuf) -> Result<Self, ImmutableFileCreationError> {
         let filename = path
             .file_stem()
-            .ok_or(format!("Couldn't extract the file stem for '{:?}'", path))?;
-        let filename = filename.to_str().ok_or(format!(
-            "Couldn't extract the filename as string for '{:?}'",
-            path
-        ))?;
-        let immutable_file_number = filename
-            .parse::<ImmutableFileNumber>()
-            .map_err(|e| e.to_string())?;
+            .ok_or(ImmutableFileCreationError::FileStemExtraction { path: path.clone() })?;
+        let filename = filename
+            .to_str()
+            .ok_or(ImmutableFileCreationError::FileNameExtraction { path: path.clone() })?;
+        let immutable_file_number = filename.parse::<ImmutableFileNumber>()?;
 
         Ok(Self {
             path,
@@ -39,15 +56,17 @@ impl ImmutableFile {
     ///
     /// Important Note: It will skip the last chunk / primary / secondary trio since they're not yet
     /// complete.
-    pub fn list_completed_in_dir(dir: &Path) -> Result<Vec<ImmutableFile>, String> {
+    pub fn list_completed_in_dir(
+        dir: &Path,
+    ) -> Result<Vec<ImmutableFile>, ImmutableFileListingError> {
         let mut files: Vec<ImmutableFile> = vec![];
 
         for path in WalkDir::new(dir)
             .into_iter()
             .filter_map(|file| file.ok())
             .map(|f| f.path().to_owned())
         {
-            let metadata = path.metadata().map_err(|e| e.to_string())?;
+            let metadata = path.metadata()?;
             if metadata.is_file() && is_immutable(&path) {
                 let immutable_file = ImmutableFile::new(path)?;
                 files.push(immutable_file);

mithril-common/src/digesters/mod.rs

@@ -4,4 +4,4 @@ mod immutable_file;
 
 pub use digester::{Digester, DigesterError, DigesterResult};
 pub use immutable_digester::ImmutableDigester;
-pub use immutable_file::ImmutableFile;
+pub use immutable_file::{ImmutableFile, ImmutableFileCreationError, ImmutableFileListingError};