use error_chain for error handling

Author: o2sh

Diff for: Cargo.lock

@@ -30,6 +30,7 @@ image = "0.23.10"
 regex = "1"
 futures = "0.3.6"
 tokio = { version = "0.2.22", features = ["full"] }
+error-chain = "0.12"
 
 [target.'cfg(windows)'.dependencies]
 ansi_term = "0.12"

Diff for: Cargo.toml

@@ -1,39 +1,15 @@
-/// Custom error type
-#[derive(Debug)]
-pub enum Error {
-    /// Sourcecode could be located
-    SourceCodeNotFound,
-    /// Git is not installed or did not function properly
-    GitNotInstalled,
-    /// Did not find any git data in the directory
-    NoGitData,
-    /// An IO error occoured while reading ./
-    ReadDirectory,
-    /// Not in a Git Repo
-    NotGitRepo,
-    /// Error while getting branch info
-    BareGitRepo,
-    /// Repository is a bare git repo
-    ReferenceInfoError,
-    /// Image probably doesn't exist or has wrong format
-    ImageLoadError,
-    /// Could not initialize the license detector
-    LicenseDetectorError,
-}
+use colored::Colorize;
+use error_chain::error_chain;
+use std::io::Write;
 
-impl std::fmt::Display for Error {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        let content = match self {
-            Error::SourceCodeNotFound => "Could not find any source code in this directory",
-            Error::GitNotInstalled => "Git failed to execute",
-            Error::NoGitData => "Could not retrieve git configuration data",
-            Error::ReadDirectory => "Could not read directory",
-            Error::NotGitRepo => "Could not find a valid git repo on the current path",
-            Error::BareGitRepo => "Unable to run onefetch on bare git repos",
-            Error::ReferenceInfoError => "Error while retrieving reference information",
-            Error::ImageLoadError => "Could not load the specified image",
-            Error::LicenseDetectorError => "Could not initialize the license detector",
-        };
-        write!(f, "{}", content)
+error_chain! {
+    foreign_links {
+        Clap(::clap::Error) #[cfg(feature = "application")];
+        Io(::std::io::Error);
+        ParseIntError(::std::num::ParseIntError);
     }
 }
+
+pub fn default_error_handler(error: &Error, output: &mut dyn Write) {
+    writeln!(output, "{}: {}", "[onefetch error]".red(), error).ok();
+}

Diff for: src/error.rs

@@ -1,9 +1,10 @@
 use {
     crate::{
+        error::*,
         language::Language,
         license::Detector,
         options::Options,
-        {AsciiArt, CommitInfo, Error},
+        {AsciiArt, CommitInfo},
     },
     colored::{Color, ColoredString, Colorize},
     git2::Repository,
@@ -13,8 +14,6 @@ use {
     tokio::process::Command,
 };
 
-type Result<T> = std::result::Result<T, crate::Error>;
-
 const LICENSE_FILES: [&str; 3] = ["LICENSE", "LICENCE", "COPYING"];
 
 #[derive(Default)]
@@ -377,8 +376,8 @@ impl std::fmt::Display for Info {
 impl Info {
     #[tokio::main]
     pub async fn new(config: Options) -> Result<Info> {
-        let repo = Repository::discover(&config.path).map_err(|_| Error::NotGitRepo)?;
-        let workdir = repo.workdir().ok_or(Error::BareGitRepo)?;
+        let repo = Repository::discover(&config.path).chain_err(||"Could not find a valid git repo on the current path")?;
+        let workdir = repo.workdir().chain_err(||"Unable to run onefetch on bare git repo")?;
         let workdir_str = workdir.to_str().unwrap();
         let (languages_stats, number_of_lines) =
             Language::get_language_stats(workdir_str, &config.excluded)?;
@@ -486,7 +485,7 @@ impl Info {
     }
 
     async fn get_repo_name_and_url(repo: &Repository) -> (String, String) {
-        let config = repo.config().map_err(|_| Error::NoGitData);
+        let config = repo.config().chain_err(|| "Could not retrieve git configuration data");
         let mut remote_url = String::new();
         let mut repository_name = String::new();
 
@@ -519,9 +518,9 @@ impl Info {
     }
 
     async fn get_current_commit_info(repo: &Repository) -> Result<CommitInfo> {
-        let head = repo.head().map_err(|_| Error::ReferenceInfoError)?;
-        let head_oid = head.target().ok_or(Error::ReferenceInfoError)?;
-        let refs = repo.references().map_err(|_| Error::ReferenceInfoError)?;
+        let head = repo.head().chain_err(|| "Error while retrieving reference information")?;
+        let head_oid = head.target().ok_or("Error while retrieving reference information")?;
+        let refs = repo.references().chain_err(|| "Error while retrieving reference information")?;
         let refs_info = refs
             .filter_map(|reference| match reference {
                 Ok(reference) => match (reference.target(), reference.shorthand()) {
@@ -754,7 +753,7 @@ impl Info {
         let detector = Detector::new()?;
 
         let mut output = fs::read_dir(dir)
-            .map_err(|_| Error::ReadDirectory)?
+            .chain_err(|| "Could not read directory")?
             .filter_map(std::result::Result::ok)
             .map(|entry| entry.path())
             .filter(|entry| {

Diff for: src/exit_codes.rs

@@ -1,5 +1,5 @@
 use {
-    crate::{Error, Result},
+    crate::error::*,
     colored::Color,
     regex::Regex,
     std::collections::HashMap,
@@ -185,7 +185,7 @@ impl Language {
     ) -> Result<(Vec<(Language, f64)>, usize)> {
         let tokei_langs = project_languages(&dir, ignored_directories);
         let languages_stat =
-            Language::get_languages_stat(&tokei_langs).ok_or(Error::SourceCodeNotFound)?;
+            Language::get_languages_stat(&tokei_langs).ok_or("ErrorKind::SourceCodeNotFound()")?;
         let mut stat_vec: Vec<(_, _)> = languages_stat.into_iter().collect();
         stat_vec.sort_by(|a, b| a.1.partial_cmp(&b.1).unwrap().reverse());
         let loc = get_total_loc(&tokei_langs);

Diff for: src/info.rs

@@ -1,8 +1,6 @@
 use askalono::{Store, TextData};
 
-use crate::Error;
-
-type Result<T> = std::result::Result<T, Error>;
+use crate::error::*;
 
 static CACHE_DATA: &[u8] = include_bytes!("../resources/licenses/cache.bin.zstd");
 const MIN_THRESHOLD: f32 = 0.8;
@@ -15,7 +13,7 @@ impl Detector {
     pub fn new() -> Result<Self> {
         Store::from_cache(CACHE_DATA)
             .map(|store| Self { store })
-            .map_err(|_| Error::LicenseDetectorError)
+            .map_err(|_| "Could not initialize the license detector".into())
     }
 
     pub fn analyze(&self, text: &str) -> Option<String> {

Diff for: src/language.rs

@@ -1,35 +1,33 @@
+// `error_chain!` can recurse deeply
+#![recursion_limit = "1024"]
+
 use {
     ascii_art::AsciiArt,
-    colored::Colorize,
     commit_info::CommitInfo,
-    error::Error,
-    exit_codes::ExitCode,
+    error::*,
     info::Info,
     language::Language,
     process::{Command, Stdio},
-    std::{convert::From, env, io::Write, process, result, str::FromStr},
+    std::{convert::From, env, process, str::FromStr},
     strum::IntoEnumIterator,
 };
 
 mod ascii_art;
 mod clap_app;
 mod commit_info;
 mod error;
-mod exit_codes;
 mod image_backends;
 mod info;
 mod language;
 mod license;
 mod options;
 
-type Result<T> = result::Result<T, Error>;
-
 fn run() -> Result<()> {
     #[cfg(windows)]
     let _ = ansi_term::enable_ansi_support();
 
     if !is_git_installed() {
-        return Err(Error::GitNotInstalled);
+        return Err("Git failed to execute!".into());
     }
 
     let matches = clap_app::build_app().get_matches_from(env::args_os());
@@ -45,7 +43,7 @@ fn run() -> Result<()> {
     };
 
     let image = if let Some(image_path) = matches.value_of("image") {
-        Some(image::open(image_path).map_err(|_| Error::ImageLoadError)?)
+        Some(image::open(image_path).chain_err(|| "Could not load the specified image")?)
     } else {
         None
     };
@@ -110,20 +108,16 @@ fn main() {
     let result = run();
     match result {
         Ok(_) => {
-            process::exit(ExitCode::Success.into());
+            process::exit(0);
         }
         Err(error) => {
             let stderr = std::io::stderr();
             default_error_handler(&error, &mut stderr.lock());
-            process::exit(ExitCode::GeneralError.into());
+            process::exit(1);
         }
     }
 }
 
-pub fn default_error_handler(error: &Error, output: &mut dyn Write) {
-    writeln!(output, "{}: {}", "[onefetch error]".red(), error).ok();
-}
-
 fn is_git_installed() -> bool {
     Command::new("git")
         .arg("--version")