Merge branch 'main' into performance

4 files changed, 101 insertions, 97 deletions

diff --git a/src/exercise.rs b/src/exercise.rs
index cdf8d20..19f528a 100644
--- a/src/exercise.rs
+++ b/src/exercise.rs
@@ -3,7 +3,7 @@ use std::fmt::{self, Display, Formatter};
 use std::fs::{self, remove_file, File};
 use std::io::{self, BufRead, BufReader};
 use std::path::PathBuf;
-use std::process::{self, exit, Command};
+use std::process::{self, exit, Command, Stdio};
 use std::{array, env, mem};
 use winnow::ascii::{space0, Caseless};
 use winnow::combinator::opt;
@@ -72,7 +72,7 @@ pub struct Exercise {
 
 // An enum to track of the state of an Exercise.
 // An Exercise can be either Done or Pending
-#[derive(PartialEq, Debug)]
+#[derive(PartialEq, Eq, Debug)]
 pub enum State {
     // The state of the exercise once it's been completed
     Done,
@@ -81,7 +81,7 @@ pub enum State {
 }
 
 // The context information of a pending exercise
-#[derive(PartialEq, Debug)]
+#[derive(PartialEq, Eq, Debug)]
 pub struct ContextLine {
     // The source code that is still pending completion
     pub line: String,
@@ -162,7 +162,10 @@ path = "{}.rs""#,
                     .args(RUSTC_COLOR_ARGS)
                     .args(RUSTC_EDITION_ARGS)
                     .args(RUSTC_NO_DEBUG_ARGS)
-                    .output()
+                    .stdin(Stdio::null())
+                    .stdout(Stdio::null())
+                    .stderr(Stdio::null())
+                    .status()
                     .expect("Failed to compile!");
                 // Due to an issue with Clippy, a cargo clean is required to catch all lints.
                 // See https://github.com/rust-lang/rust-clippy/issues/2604
@@ -171,7 +174,10 @@ path = "{}.rs""#,
                 Command::new("cargo")
                     .args(["clean", "--manifest-path", CLIPPY_CARGO_TOML_PATH])
                     .args(RUSTC_COLOR_ARGS)
-                    .output()
+                    .stdin(Stdio::null())
+                    .stdout(Stdio::null())
+                    .stderr(Stdio::null())
+                    .status()
                     .expect("Failed to run 'cargo clean'");
                 Command::new("cargo")
                     .args(["clippy", "--manifest-path", CLIPPY_CARGO_TOML_PATH])
diff --git a/src/main.rs b/src/main.rs
index f646fdc..a513e71 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,11 +6,12 @@ use clap::{Parser, Subcommand};
 use console::Emoji;
 use notify_debouncer_mini::notify::{self, RecursiveMode};
 use notify_debouncer_mini::{new_debouncer, DebouncedEventKind};
+use shlex::Shlex;
 use std::ffi::OsStr;
 use std::fs;
 use std::io::{self, prelude::*};
 use std::path::Path;
-use std::process::{Command, Stdio};
+use std::process::Command;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::{channel, RecvTimeoutError};
 use std::sync::{Arc, Mutex};
@@ -91,24 +92,25 @@ fn main() {
         println!("\n{WELCOME}\n");
     }
 
-    if !Path::new("info.toml").exists() {
-        println!(
-            "{} must be run from the rustlings directory",
-            std::env::current_exe().unwrap().to_str().unwrap()
-        );
-        println!("Try `cd rustlings/`!");
-        std::process::exit(1);
-    }
-
-    if !rustc_exists() {
+    if which::which("rustc").is_err() {
         println!("We cannot find `rustc`.");
         println!("Try running `rustc --version` to diagnose your problem.");
         println!("For instructions on how to install Rust, check the README.");
         std::process::exit(1);
     }
 
-    let toml_str = &fs::read_to_string("info.toml").unwrap();
-    let exercises = toml::from_str::<ExerciseList>(toml_str).unwrap().exercises;
+    let info_file = fs::read_to_string("info.toml").unwrap_or_else(|e| {
+        match e.kind() {
+            io::ErrorKind::NotFound => println!(
+                "The program must be run from the rustlings directory\nTry `cd rustlings/`!",
+            ),
+            _ => println!("Failed to read the info.toml file: {e}"),
+        }
+        std::process::exit(1);
+    });
+    let exercises = toml_edit::de::from_str::<ExerciseList>(&info_file)
+        .unwrap()
+        .exercises;
     let verbose = args.nocapture;
 
     let command = args.command.unwrap_or_else(|| {
@@ -230,16 +232,13 @@ fn main() {
                 println!("Failed to write rust-project.json to disk for rust-analyzer");
             } else {
                 println!("Successfully generated rust-project.json");
-                println!("rust-analyzer will now parse exercises, restart your language server or editor")
+                println!("rust-analyzer will now parse exercises, restart your language server or editor");
             }
         }
 
         Subcommands::Watch { success_hints } => match watch(&exercises, verbose, success_hints) {
             Err(e) => {
-                println!(
-                    "Error: Could not watch your progress. Error message was {:?}.",
-                    e
-                );
+                println!("Error: Could not watch your progress. Error message was {e:?}.");
                 println!("Most likely you've run out of disk space or your 'inotify limit' has been reached.");
                 std::process::exit(1);
             }
@@ -259,53 +258,55 @@ fn main() {
 }
 
 fn spawn_watch_shell(
-    failed_exercise_hint: &Arc<Mutex<Option<String>>>,
+    failed_exercise_hint: Arc<Mutex<Option<String>>>,
     should_quit: Arc<AtomicBool>,
 ) {
-    let failed_exercise_hint = Arc::clone(failed_exercise_hint);
     println!("Welcome to watch mode! You can type 'help' to get an overview of the commands you can use here.");
-    thread::spawn(move || loop {
-        let mut input = String::new();
-        match io::stdin().read_line(&mut input) {
-            Ok(_) => {
-                let input = input.trim();
-                if input == "hint" {
-                    if let Some(hint) = &*failed_exercise_hint.lock().unwrap() {
-                        println!("{hint}");
-                    }
-                } else if input == "clear" {
-                    println!("\x1B[2J\x1B[1;1H");
-                } else if input.eq("quit") {
-                    should_quit.store(true, Ordering::SeqCst);
-                    println!("Bye!");
-                } else if input.eq("help") {
-                    println!("Commands available to you in watch mode:");
-                    println!("  hint   - prints the current exercise's hint");
-                    println!("  clear  - clears the screen");
-                    println!("  quit   - quits watch mode");
-                    println!("  !<cmd> - executes a command, like `!rustc --explain E0381`");
-                    println!("  help   - displays this help message");
-                    println!();
-                    println!("Watch mode automatically re-evaluates the current exercise");
-                    println!("when you edit a file's contents.")
-                } else if let Some(cmd) = input.strip_prefix('!') {
-                    let parts: Vec<&str> = cmd.split_whitespace().collect();
-                    if parts.is_empty() {
-                        println!("no command provided");
-                    } else if let Err(e) = Command::new(parts[0]).args(&parts[1..]).status() {
-                        println!("failed to execute command `{}`: {}", cmd, e);
-                    }
-                } else {
-                    println!("unknown command: {input}");
+
+    thread::spawn(move || {
+        let mut input = String::with_capacity(32);
+        let mut stdin = io::stdin().lock();
+
+        loop {
+            // Recycle input buffer.
+            input.clear();
+
+            if let Err(e) = stdin.read_line(&mut input) {
+                println!("error reading command: {e}");
+            }
+
+            let input = input.trim();
+            if input == "hint" {
+                if let Some(hint) = &*failed_exercise_hint.lock().unwrap() {
+                    println!("{hint}");
+                }
+            } else if input == "clear" {
+                println!("\x1B[2J\x1B[1;1H");
+            } else if input == "quit" {
+                should_quit.store(true, Ordering::SeqCst);
+                println!("Bye!");
+            } else if input == "help" {
+                println!("{WATCH_MODE_HELP_MESSAGE}");
+            } else if let Some(cmd) = input.strip_prefix('!') {
+                let mut parts = Shlex::new(cmd);
+
+                let Some(program) = parts.next() else {
+                    println!("no command provided");
+                    continue;
+                };
+
+                if let Err(e) = Command::new(program).args(parts).status() {
+                    println!("failed to execute command `{cmd}`: {e}");
                 }
+            } else {
+                println!("unknown command: {input}\n{WATCH_MODE_HELP_MESSAGE}");
             }
-            Err(error) => println!("error reading command: {error}"),
         }
     });
 }
 
 fn find_exercise<'a>(name: &str, exercises: &'a [Exercise]) -> &'a Exercise {
-    if name.eq("next") {
+    if name == "next" {
         exercises
             .iter()
             .find(|e| !e.looks_done())
@@ -351,7 +352,6 @@ fn watch(
 
     clear_screen();
 
-    let to_owned_hint = |t: &Exercise| t.hint.to_owned();
     let failed_exercise_hint = match verify(
         exercises.iter(),
         (0, exercises.len()),
@@ -359,9 +359,9 @@ fn watch(
         success_hints,
     ) {
         Ok(_) => return Ok(WatchStatus::Finished),
-        Err(exercise) => Arc::new(Mutex::new(Some(to_owned_hint(exercise)))),
+        Err(exercise) => Arc::new(Mutex::new(Some(exercise.hint.clone()))),
     };
-    spawn_watch_shell(&failed_exercise_hint, Arc::clone(&should_quit));
+    spawn_watch_shell(Arc::clone(&failed_exercise_hint), Arc::clone(&should_quit));
     loop {
         match rx.recv_timeout(Duration::from_secs(1)) {
             Ok(event) => match event {
@@ -396,7 +396,7 @@ fn watch(
                                 Err(exercise) => {
                                     let mut failed_exercise_hint =
                                         failed_exercise_hint.lock().unwrap();
-                                    *failed_exercise_hint = Some(to_owned_hint(exercise));
+                                    *failed_exercise_hint = Some(exercise.hint.clone());
                                 }
                             }
                         }
@@ -416,19 +416,7 @@ fn watch(
     }
 }
 
-fn rustc_exists() -> bool {
-    Command::new("rustc")
-        .args(["--version"])
-        .stdout(Stdio::null())
-        .stderr(Stdio::null())
-        .stdin(Stdio::null())
-        .spawn()
-        .and_then(|mut child| child.wait())
-        .map(|status| status.success())
-        .unwrap_or(false)
-}
-
-const DEFAULT_OUT: &str = r#"Thanks for installing Rustlings!
+const DEFAULT_OUT: &str = "Thanks for installing Rustlings!
 
 Is this your first time? Don't worry, Rustlings was made for beginners! We are
 going to teach you a lot of things about Rust, but before we can get
@@ -454,7 +442,7 @@ started, here's a couple of notes about how Rustlings operates:
    autocompletion, run the command `rustlings lsp`.
 
 Got all that? Great! To get started, run `rustlings watch` in order to get the first
-exercise. Make sure to have your editor open!"#;
+exercise. Make sure to have your editor open!";
 
 const FENISH_LINE: &str = "+----------------------------------------------------+
 |          You made it to the Fe-nish line!          |
@@ -490,3 +478,13 @@ const WELCOME: &str = r"       welcome to...
  | |  | |_| \__ \ |_| | | | | | (_| \__ \
  |_|   \__,_|___/\__|_|_|_| |_|\__, |___/
                                |___/";
+
+const WATCH_MODE_HELP_MESSAGE: &str = "Commands available to you in watch mode:
+  hint   - prints the current exercise's hint
+  clear  - clears the screen
+  quit   - quits watch mode
+  !<cmd> - executes a command, like `!rustc --explain E0381`
+  help   - displays this help message
+
+Watch mode automatically re-evaluates the current exercise
+when you edit a file's contents.";
diff --git a/src/run.rs b/src/run.rs
index e0ada4c..6dd0388 100644
--- a/src/run.rs
+++ b/src/run.rs
@@ -21,7 +21,8 @@ pub fn run(exercise: &Exercise, verbose: bool) -> Result<(), ()> {
 // Resets the exercise by stashing the changes.
 pub fn reset(exercise: &Exercise) -> Result<(), ()> {
     let command = Command::new("git")
-        .args(["stash", "--"])
+        .arg("stash")
+        .arg("--")
         .arg(&exercise.path)
         .spawn();
 
diff --git a/src/verify.rs b/src/verify.rs
index e3a8e88..5275bf7 100644
--- a/src/verify.rs
+++ b/src/verify.rs
@@ -24,7 +24,7 @@ pub fn verify<'a>(
             .progress_chars("#>-"),
     );
     bar.set_position(num_done as u64);
-    bar.set_message(format!("({:.1} %)", percentage));
+    bar.set_message(format!("({percentage:.1} %)"));
 
     for exercise in exercises {
         let compile_result = match exercise.mode {
@@ -37,7 +37,7 @@ pub fn verify<'a>(
         }
         percentage += 100.0 / total as f32;
         bar.inc(1);
-        bar.set_message(format!("({:.1} %)", percentage));
+        bar.set_message(format!("({percentage:.1} %)"));
         if bar.position() == total as u64 {
             println!(
                 "Progress: You completed {} / {} exercises ({:.1} %).",
@@ -51,6 +51,7 @@ pub fn verify<'a>(
     Ok(())
 }
 
+#[derive(PartialEq, Eq)]
 enum RunMode {
     Interactive,
     NonInteractive,
@@ -124,7 +125,7 @@ fn compile_and_test(
             if verbose {
                 println!("{}", output.stdout);
             }
-            if let RunMode::Interactive = run_mode {
+            if run_mode == RunMode::Interactive {
                 Ok(prompt_for_completion(exercise, None, success_hints))
             } else {
                 Ok(true)
@@ -191,27 +192,25 @@ fn prompt_for_completion(
         Mode::Test => "The code is compiling, and the tests pass!",
         Mode::Clippy => clippy_success_msg,
     };
-    println!();
+
     if no_emoji {
-        println!("~*~ {success_msg} ~*~")
+        println!("\n~*~ {success_msg} ~*~\n");
     } else {
-        println!("🎉 🎉  {success_msg} 🎉 🎉")
+        println!("\n🎉 🎉  {success_msg} 🎉 🎉\n");
     }
-    println!();
 
     if let Some(output) = prompt_output {
-        println!("Output:");
-        println!("{}", separator());
-        println!("{output}");
-        println!("{}", separator());
-        println!();
+        println!(
+            "Output:\n{separator}\n{output}\n{separator}\n",
+            separator = separator(),
+        );
     }
     if success_hints {
-        println!("Hints:");
-        println!("{}", separator());
-        println!("{}", exercise.hint);
-        println!("{}", separator());
-        println!();
+        println!(
+            "Hints:\n{separator}\n{}\n{separator}\n",
+            exercise.hint,
+            separator = separator(),
+        );
     }
 
     println!("You can keep working on this exercise,");
@@ -231,7 +230,7 @@ fn prompt_for_completion(
             "{:>2} {}  {}",
             style(context_line.number).blue().bold(),
             style("|").blue(),
-            formatted_line
+            formatted_line,
         );
     }