add path to error handling

Author: steveklabnik

src/oxide_controller/config.rs

@@ -8,7 +8,7 @@ use dropshot::ConfigLogging;
 use serde::Deserialize;
 use serde::Serialize;
 use std::fmt;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 /**
  * Configuration for an OXC server
@@ -24,34 +24,45 @@ pub struct ConfigController {
 }
 
 #[derive(Debug)]
-pub enum LoadError {
+pub struct LoadError {
+    path: PathBuf,
+    kind: LoadErrorKind,
+}
+#[derive(Debug)]
+pub enum LoadErrorKind {
     Io(std::io::Error),
     Parse(toml::de::Error),
 }
 
-impl From<std::io::Error> for LoadError {
-    fn from(err: std::io::Error) -> Self {
-        LoadError::Io(err)
+impl From<(PathBuf, std::io::Error)> for LoadError {
+    fn from((path, err): (PathBuf, std::io::Error)) -> Self {
+        LoadError {
+            path,
+            kind: LoadErrorKind::Io(err)
+        }
     }
 }
-impl From<toml::de::Error> for LoadError {
-    fn from(err: toml::de::Error) -> Self {
-        LoadError::Parse(err)
+
+impl From<(PathBuf, toml::de::Error)> for LoadError {
+    fn from((path, err): (PathBuf, toml::de::Error)) -> Self {
+        LoadError {
+            path,
+            kind: LoadErrorKind::Parse(err)
+        }
     }
 }
 
 impl std::error::Error for LoadError {}
 
 impl fmt::Display for LoadError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        // default to debug for now
-        write!(f, "{:?}", self)
+        write!(f, "read {}: {:?}", self.path.display(), self.kind)
     }
 }
 
 impl std::cmp::PartialEq<std::io::Error> for LoadError {
     fn eq(&self, other: &std::io::Error) -> bool {
-        if let LoadError::Io(e) = self {
+        if let LoadErrorKind::Io(e) = &self.kind {
             e.kind() == other.kind()
         } else {
             false
@@ -67,16 +78,20 @@ impl ConfigController {
      * The format is described in the README.
      */
     pub fn from_file(path: &Path) -> Result<ConfigController, LoadError> {
-        let file_contents = std::fs::read_to_string(path)?;
-        let config_parsed: ConfigController = toml::from_str(&file_contents)?;
+        let file_contents = std::fs::read_to_string(path).map_err(|e| {
+            (path.to_path_buf(), e)
+        })?;
+        let config_parsed: ConfigController = toml::from_str(&file_contents).map_err(|e| {
+            (path.to_path_buf(), e)
+        })?;
         Ok(config_parsed)
     }
 }
 
 #[cfg(test)]
 mod test {
     use super::ConfigController;
-    use super::LoadError;
+    use super::{LoadErrorKind, LoadError};
     use dropshot::ConfigDropshot;
     use dropshot::ConfigLogging;
     use dropshot::ConfigLoggingIfExists;
@@ -141,7 +156,7 @@ mod test {
     fn test_config_bad_toml() {
         let error =
             read_config("bad_toml", "foo =").expect_err("expected failure");
-        if let LoadError::Parse(error) = error {
+        if let LoadErrorKind::Parse(error) = &error.kind {
             assert_eq!(error.line_col(), Some((0, 5)));
         } else {
             panic!(
@@ -159,7 +174,7 @@ mod test {
     #[test]
     fn test_config_empty() {
         let error = read_config("empty", "").expect_err("expected failure");
-        if let LoadError::Parse(error) = error {
+        if let LoadErrorKind::Parse(error) = &error.kind {
             assert_eq!(error.line_col(), None);
         } else {
             panic!(