eh: clean up dispatch logic

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I63671355750a3c839f71d9155b8c918d6a6a6964

eh/src/command.rs

@@ -62,17 +62,20 @@ impl NixCommand {
         self
     }
 
-    #[must_use] pub const fn impure(mut self, yes: bool) -> Self {
+    #[must_use]
+    pub const fn impure(mut self, yes: bool) -> Self {
         self.impure = yes;
         self
     }
 
-    #[must_use] pub const fn interactive(mut self, yes: bool) -> Self {
+    #[must_use]
+    pub const fn interactive(mut self, yes: bool) -> Self {
         self.interactive = yes;
         self
     }
 
-    #[must_use] pub const fn print_build_logs(mut self, yes: bool) -> Self {
+    #[must_use]
+    pub const fn print_build_logs(mut self, yes: bool) -> Self {
         self.print_build_logs = yes;
         self
     }

eh/src/error.rs

@@ -33,7 +33,8 @@ pub enum EhError {
 pub type Result<T> = std::result::Result<T, EhError>;
 
 impl EhError {
-    #[must_use] pub const fn exit_code(&self) -> i32 {
+    #[must_use]
+    pub const fn exit_code(&self) -> i32 {
         match self {
             Self::ProcessExit { code } => *code,
             Self::NixCommandFailed(_) => 1,

eh/src/main.rs

@@ -30,6 +30,36 @@ fn main() {
     }
 }
 
+// Design partially taken from Stash
+fn dispatch_multicall(app_name: &str, args: std::env::Args) -> Option<Result<i32>> {
+    let rest: Vec<String> = args.collect();
+    let hash_extractor = util::RegexHashExtractor;
+    let fixer = util::DefaultNixFileFixer;
+    let classifier = util::DefaultNixErrorClassifier;
+
+    match app_name {
+        "nr" => Some(run::handle_nix_run(
+            &rest,
+            &hash_extractor,
+            &fixer,
+            &classifier,
+        )),
+        "ns" => Some(shell::handle_nix_shell(
+            &rest,
+            &hash_extractor,
+            &fixer,
+            &classifier,
+        )),
+        "nb" => Some(build::handle_nix_build(
+            &rest,
+            &hash_extractor,
+            &fixer,
+            &classifier,
+        )),
+        _ => None,
+    }
+}
+
 fn run_app() -> Result<i32> {
     let mut args = env::args();
     let bin = args.next().unwrap_or_else(|| "eh".to_string());
@@ -39,31 +69,8 @@ fn run_app() -> Result<i32> {
         .unwrap_or("eh");
 
     // If invoked as nr/ns/nb, dispatch directly and exit
-    match app_name {
+    if let Some(result) = dispatch_multicall(app_name, args) {
-        "nr" => {
+        return result;
-            let rest: Vec<String> = args.collect();
-            let hash_extractor = util::RegexHashExtractor;
-            let fixer = util::DefaultNixFileFixer;
-            let classifier = util::DefaultNixErrorClassifier;
-            return run::handle_nix_run(&rest, &hash_extractor, &fixer, &classifier);
-        }
-
-        "ns" => {
-            let rest: Vec<String> = args.collect();
-            let hash_extractor = util::RegexHashExtractor;
-            let fixer = util::DefaultNixFileFixer;
-            let classifier = util::DefaultNixErrorClassifier;
-            return shell::handle_nix_shell(&rest, &hash_extractor, &fixer, &classifier);
-        }
-
-        "nb" => {
-            let rest: Vec<String> = args.collect();
-            let hash_extractor = util::RegexHashExtractor;
-            let fixer = util::DefaultNixFileFixer;
-            let classifier = util::DefaultNixErrorClassifier;
-            return build::handle_nix_build(&rest, &hash_extractor, &fixer, &classifier);
-        }
-        _ => {}
     }
 
     let cli = Cli::parse();

eh/src/util.rs

@@ -23,7 +23,8 @@ impl HashExtractor for RegexHashExtractor {
         for pattern in &patterns {
             if let Ok(re) = Regex::new(pattern)
                 && let Some(captures) = re.captures(stderr)
-                    && let Some(hash) = captures.get(1) {
+                && let Some(hash) = captures.get(1)
+            {
                 return Some(hash.as_str().to_string());
             }
         }
@@ -62,7 +63,8 @@ impl NixFileFixer for DefaultNixFileFixer {
                 if path.is_dir() {
                     stack.push(path);
                 } else if let Some(ext) = path.extension()
-                    && ext.eq_ignore_ascii_case("nix") {
+                    && ext.eq_ignore_ascii_case("nix")
+                {
                     files.push(path);
                 }
             }
@@ -99,9 +101,8 @@ impl NixFileFixer for DefaultNixFileFixer {
             }
         }
         if replaced {
-            fs::write(file_path, new_content)
+            fs::write(file_path, new_content).map_err(|_| EhError::HashFixFailed {
-                .map_err(|_| EhError::HashFixFailed { 
+                path: file_path.to_string_lossy().to_string(),
-                    path: file_path.to_string_lossy().to_string() 
             })?;
             Ok(true)
         } else {