Use derive(Debug) for Error (#35)

This change help us to save 13 LOC.

Additionally, this PR makes config errors more explicit (including file path and line number)

src/config.rs

@@ -9,7 +9,7 @@ use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::time::Duration;
 
-use crate::{sys::conf_dirs, Error};
+use crate::{sys::conf_dirs, Error, Error::Config as ConfErr};
 
 /// The global Kibi configuration.
 pub struct Config {
@@ -85,18 +85,18 @@ impl Config {
 
 /// Process an INI file.
 ///
-/// The `deser_fn` will be called for each key-value pair in the file. Typically, this function will
-/// update a configuration instance.
-pub(crate) fn process_ini_file<F>(path: &Path, deser_fn: &mut F) -> Result<(), Error>
+/// The `kv_fn` function will be called for each key-value pair in the file. Typically, this
+/// function will update a configuration instance.
+pub(crate) fn process_ini_file<F>(path: &Path, kv_fn: &mut F) -> Result<(), Error>
 where F: FnMut(&str, &str) -> Result<(), String> {
-    for line in BufReader::new(File::open(path)?).lines() {
+    for (i, line) in BufReader::new(File::open(path)?).lines().enumerate() {
         let line = line?;
         let mut parts = line.trim_start().splitn(2, '=');
         match (parts.next(), parts.next()) {
             (Some(comment_line), _) if comment_line.starts_with(&['#', ';'][..]) => (),
-            (Some(k), Some(v)) => deser_fn(k.trim_end(), v).map_err(|r| Error::Config(line, r))?,
+            (Some(k), Some(v)) => kv_fn(k.trim_end(), v).map_err(|r| ConfErr(path.into(), i, r))?,
             (Some(""), None) | (None, _) => (), // Empty line
-            (Some(_), None) => return Err(Error::Config(line, String::from("No '='"))),
+            (Some(_), None) => return Err(ConfErr(path.into(), i, String::from("No '='"))),
         }
     }
     Ok(())

src/error.rs

@@ -1,42 +1,34 @@
 //! # Errors
 
-use std::fmt::{self, Debug, Formatter};
-
-/// These errors can used in the program.
+/// Kibi error type.
+#[derive(Debug)]
 pub enum Error {
+    /// Wrapper around `std::io::Error`
     IO(std::io::Error),
+    /// Wrapper around `nix::Error`
     #[cfg(unix)]
     Nix(nix::Error),
-    InvalidWindowSize,
+    /// Wrapper around `std::sync::mpsc::TryRecvError`
     MPSCTryRecv(std::sync::mpsc::TryRecvError),
+    /// Error returned when the window size obtained through a system call is invalid.
+    InvalidWindowSize,
+    /// Error setting or retrieving the cursor position.
     CursorPosition,
-    Config(String, String),
+    /// Configuration error. The three attributes correspond the file path, the line number and the
+    /// error message.
+    Config(std::path::PathBuf, usize, String),
+    /// Too many arguments given to kibi. The attribute corresponds to the total number of command
+    /// line armuments.
     TooManyArguments(usize),
 }
 
-impl Debug for Error {
-    /// Format the value using the given formatter.
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        match self {
-            Self::IO(err) => write!(f, "IO error: {}", err),
-            #[cfg(unix)]
-            Self::Nix(err) => write!(f, "System call error: {}", err),
-            Self::InvalidWindowSize => write!(f, "Invalid window size"),
-            Self::MPSCTryRecv(err) => write!(f, "MSPC try_recv error: {}", err),
-            Self::CursorPosition => write!(f, "Could not obtain cursor position"),
-            Self::Config(line, reason) => write!(f, "Could not parse config {}: {}", line, reason),
-            Self::TooManyArguments(n) => write!(f, "Expected 0 or 1 argument, got {}", n),
-        }
-    }
-}
-
 impl From<std::io::Error> for Error {
     /// Convert an IO Error into a Kibi Error.
     fn from(err: std::io::Error) -> Self { Self::IO(err) }
 }
 
 #[cfg(unix)]
 impl From<nix::Error> for Error {
-    /// Convert a nix IO Error into a Kibi Error.
+    /// Convert a nix Error into a Kibi Error.
     fn from(err: nix::Error) -> Self { Self::Nix(err) }
 }

src/unix.rs

@@ -21,7 +21,7 @@ pub(crate) fn conf_dirs() -> [Option<String>; 3] {
 
 /// Return the current window size as (rows, columns).
 ///
-/// We use the TIOCGWINSZ ioctl to get window size. If it succeeds, a `Winsize` struct will be
+/// We use the `TIOCGWINSZ` ioctl to get window size. If it succeeds, a `Winsize` struct will be
 /// populated.
 /// This ioctl is described here: <http://man7.org/linux/man-pages/man4/tty_ioctl.4.html>
 pub(crate) fn get_window_size() -> Result<(usize, usize), Error> {