Avoid asking for terminal size on each rendering

Cargo.lock

@@ -95,9 +95,9 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
 name = "clap"
-version = "4.5.16"
+version = "4.5.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed6719fffa43d0d87e5fd8caeab59be1554fb028cd30edc88fc4369b17971019"
+checksum = "3e5a21b8495e732f1b3c364c9949b201ca7bae518c502c80256c96ad79eaf6ac"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -105,9 +105,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.5.15"
+version = "4.5.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "216aec2b177652e3846684cbfe25c9964d18ec45234f0f5da5157b207ed1aab6"
+checksum = "8cf2dd12af7a047ad9d6da2b6b249759a22a7abc0f474c1dae1777afa4b21a73"
 dependencies = [
  "anstream",
  "anstyle",
@@ -242,9 +242,9 @@ checksum = "d231dfb89cfffdbc30e7fc41579ed6066ad03abda9e567ccafae602b97ec5024"
 
 [[package]]
 name = "indexmap"
-version = "2.4.0"
+version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "93ead53efc7ea8ed3cfb0c79fc8023fbb782a5432b52830b6518941cebe6505c"
+checksum = "68b900aa2f7301e21c36462b170ee99994de34dff39a4a6a528e80e7376d07e5"
 dependencies = [
  "equivalent",
  "hashbrown",
@@ -490,6 +490,7 @@ dependencies = [
  "crossterm",
  "notify-debouncer-mini",
  "os_pipe",
+ "rustix",
  "rustlings-macros",
  "serde",
  "serde_json",
@@ -549,9 +550,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.127"
+version = "1.0.128"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8043c06d9f82bd7271361ed64f415fe5e12a77fdb52e573e7f06a516dea329ad"
+checksum = "6ff5456707a1de34e7e37f2a6fd3d3f808c318259cbd01ab6377795054b483d8"
 dependencies = [
  "itoa",
  "memchr",
@@ -612,9 +613,9 @@ checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
 [[package]]
 name = "syn"
-version = "2.0.76"
+version = "2.0.77"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "578e081a14e0cefc3279b0472138c513f37b41a08d5a3cca9b6e4e8ceb6cd525"
+checksum = "9f35bcdf61fd8e7be6caf75f429fdca8beb3ed76584befb503b1569faee373ed"
 dependencies = [
  "proc-macro2",
  "quote",

Cargo.toml

@@ -48,15 +48,18 @@ include = [
 [dependencies]
 ahash = { version = "0.8.11", default-features = false }
 anyhow = "1.0.86"
-clap = { version = "4.5.16", features = ["derive"] }
+clap = { version = "4.5.17", features = ["derive"] }
 crossterm = { version = "0.28.1", default-features = false, features = ["windows", "events"] }
 notify-debouncer-mini = { version = "0.4.1", default-features = false }
 os_pipe = "1.2.1"
 rustlings-macros = { path = "rustlings-macros", version = "=6.3.0" }
-serde_json = "1.0.127"
+serde_json = "1.0.128"
 serde.workspace = true
 toml_edit.workspace = true
 
+[target.'cfg(not(windows))'.dependencies]
+rustix = { version = "0.38.35", default-features = false, features = ["std", "stdio", "termios"] }
+
 [dev-dependencies]
 tempfile = "3.12.0"
 

src/app_state.rs

@@ -24,10 +24,10 @@ const STATE_FILE_NAME: &str = ".rustlings-state.txt";
 pub enum ExercisesProgress {
     // All exercises are done.
     AllDone,
-    // The current exercise failed and is still pending.
-    CurrentPending,
     // A new exercise is now pending.
     NewPending,
+    // The current exercise is still pending.
+    CurrentPending,
 }
 
 pub enum StateFileStatus {

src/embedded.rs

@@ -1,7 +1,7 @@
 use anyhow::{Context, Error, Result};
 use std::{
-    fs::{create_dir, OpenOptions},
+    fs::{self, create_dir},
-    io::{self, Write},
+    io,
 };
 
 use crate::info_file::ExerciseInfo;
@@ -9,29 +9,6 @@ use crate::info_file::ExerciseInfo;
 /// Contains all embedded files.
 pub static EMBEDDED_FILES: EmbeddedFiles = rustlings_macros::include_files!();
 
-#[derive(Clone, Copy)]
-pub enum WriteStrategy {
-    IfNotExists,
-    Overwrite,
-}
-
-impl WriteStrategy {
-    fn write(self, path: &str, content: &[u8]) -> Result<()> {
-        let file = match self {
-            Self::IfNotExists => OpenOptions::new().create_new(true).write(true).open(path),
-            Self::Overwrite => OpenOptions::new()
-                .create(true)
-                .write(true)
-                .truncate(true)
-                .open(path),
-        };
-
-        file.with_context(|| format!("Failed to open the file `{path}` in write mode"))?
-            .write_all(content)
-            .with_context(|| format!("Failed to write the file {path}"))
-    }
-}
-
 // Files related to one exercise.
 struct ExerciseFiles {
     // The content of the exercise file.
@@ -42,6 +19,16 @@ struct ExerciseFiles {
     dir_ind: usize,
 }
 
+fn create_dir_if_not_exists(path: &str) -> Result<()> {
+    if let Err(e) = create_dir(path) {
+        if e.kind() != io::ErrorKind::AlreadyExists {
+            return Err(Error::from(e).context(format!("Failed to create the directory {path}")));
+        }
+    }
+
+    Ok(())
+}
+
 // A directory in the `exercises/` directory.
 pub struct ExerciseDir {
     pub name: &'static str,
@@ -55,21 +42,13 @@ impl ExerciseDir {
         let mut dir_path = String::with_capacity(20 + self.name.len());
         dir_path.push_str("exercises/");
         dir_path.push_str(self.name);
-
+        create_dir_if_not_exists(&dir_path)?;
-        if let Err(e) = create_dir(&dir_path) {
-            if e.kind() == io::ErrorKind::AlreadyExists {
-                return Ok(());
-            }
-
-            return Err(
-                Error::from(e).context(format!("Failed to create the directory {dir_path}"))
-            );
-        }
 
         let mut readme_path = dir_path;
         readme_path.push_str("/README.md");
 
-        WriteStrategy::Overwrite.write(&readme_path, self.readme)
+        fs::write(&readme_path, self.readme)
+            .with_context(|| format!("Failed to write the file {readme_path}"))
     }
 }
 
@@ -86,17 +65,31 @@ impl EmbeddedFiles {
     pub fn init_exercises_dir(&self, exercise_infos: &[ExerciseInfo]) -> Result<()> {
         create_dir("exercises").context("Failed to create the directory `exercises`")?;
 
-        WriteStrategy::IfNotExists.write(
+        fs::write(
             "exercises/README.md",
             include_bytes!("../exercises/README.md"),
-        )?;
+        )
+        .context("Failed to write the file exercises/README.md")?;
 
         for dir in self.exercise_dirs {
             dir.init_on_disk()?;
         }
 
+        let mut exercise_path = String::with_capacity(64);
+        let prefix = "exercises/";
+        exercise_path.push_str(prefix);
+
         for (exercise_info, exercise_files) in exercise_infos.iter().zip(self.exercise_files) {
-            WriteStrategy::IfNotExists.write(&exercise_info.path(), exercise_files.exercise)?;
+            let dir = &self.exercise_dirs[exercise_files.dir_ind];
+
+            exercise_path.truncate(prefix.len());
+            exercise_path.push_str(dir.name);
+            exercise_path.push('/');
+            exercise_path.push_str(&exercise_info.name);
+            exercise_path.push_str(".rs");
+
+            fs::write(&exercise_path, exercise_files.exercise)
+                .with_context(|| format!("Failed to write the exercise file {exercise_path}"))?;
         }
 
         Ok(())
@@ -107,7 +100,8 @@ impl EmbeddedFiles {
         let dir = &self.exercise_dirs[exercise_files.dir_ind];
 
         dir.init_on_disk()?;
-        WriteStrategy::Overwrite.write(path, exercise_files.exercise)
+        fs::write(path, exercise_files.exercise)
+            .with_context(|| format!("Failed to write the exercise file {path}"))
     }
 
     /// Write the solution file to disk and return its path.
@@ -116,19 +110,25 @@ impl EmbeddedFiles {
         exercise_ind: usize,
         exercise_name: &str,
     ) -> Result<String> {
+        create_dir_if_not_exists("solutions")?;
+
         let exercise_files = &self.exercise_files[exercise_ind];
         let dir = &self.exercise_dirs[exercise_files.dir_ind];
 
         // 14 = 10 + 1 + 3
         // solutions/ + / + .rs
-        let mut solution_path = String::with_capacity(14 + dir.name.len() + exercise_name.len());
+        let mut dir_path = String::with_capacity(14 + dir.name.len() + exercise_name.len());
-        solution_path.push_str("solutions/");
+        dir_path.push_str("solutions/");
-        solution_path.push_str(dir.name);
+        dir_path.push_str(dir.name);
+        create_dir_if_not_exists(&dir_path)?;
+
+        let mut solution_path = dir_path;
         solution_path.push('/');
         solution_path.push_str(exercise_name);
         solution_path.push_str(".rs");
 
-        WriteStrategy::Overwrite.write(&solution_path, exercise_files.solution)?;
+        fs::write(&solution_path, exercise_files.solution)
+            .with_context(|| format!("Failed to write the solution file {solution_path}"))?;
 
         Ok(solution_path)
     }

src/list.rs

@@ -20,7 +20,7 @@ mod scroll_state;
 mod state;
 
 fn handle_list(app_state: &mut AppState, stdout: &mut StdoutLock) -> Result<()> {
-    let mut list_state = ListState::new(app_state, stdout)?;
+    let mut list_state = ListState::build(app_state, stdout)?;
     let mut is_searching = false;
 
     loop {

src/list/state.rs

@@ -48,7 +48,7 @@ pub struct ListState<'a> {
 }
 
 impl<'a> ListState<'a> {
-    pub fn new(app_state: &'a mut AppState, stdout: &mut StdoutLock) -> io::Result<Self> {
+    pub fn build(app_state: &'a mut AppState, stdout: &mut StdoutLock) -> Result<Self> {
         stdout.queue(Clear(ClearType::All))?;
 
         let name_col_title_len = 4;
@@ -64,7 +64,7 @@ impl<'a> ListState<'a> {
         let n_rows_with_filter = app_state.exercises().len();
         let selected = app_state.current_exercise_ind();
 
-        let (width, height) = terminal::size()?;
+        let (width, height) = terminal::size().context("Failed to get the terminal size")?;
         let scroll_state = ScrollState::new(n_rows_with_filter, Some(selected), 5);
 
         let mut slf = Self {

src/main.rs

@@ -8,7 +8,7 @@ use std::{
 };
 use term::{clear_terminal, press_enter_prompt};
 
-use self::{app_state::AppState, dev::DevCommands, info_file::InfoFile, watch::WatchExit};
+use self::{app_state::AppState, dev::DevCommands, info_file::InfoFile};
 
 mod app_state;
 mod cargo_toml;
@@ -130,15 +130,7 @@ fn main() -> Result<()> {
                 )
             };
 
-            loop {
+            watch::watch(&mut app_state, notify_exercise_names)?;
-                match watch::watch(&mut app_state, notify_exercise_names)? {
-                    WatchExit::Shutdown => break,
-                    // It is much easier to exit the watch mode, launch the list mode and then restart
-                    // the watch mode instead of trying to pause the watch threads and correct the
-                    // watch state.
-                    WatchExit::List => list::list(&mut app_state)?,
-                }
-            }
         }
         Some(Subcommands::Run { name }) => {
             if let Some(name) = name {

src/run.rs

@@ -45,7 +45,7 @@ pub fn run(app_state: &mut AppState) -> Result<()> {
     }
 
     match app_state.done_current_exercise(&mut stdout)? {
-        ExercisesProgress::CurrentPending | ExercisesProgress::NewPending => {
+        ExercisesProgress::NewPending | ExercisesProgress::CurrentPending => {
             stdout.write_all(b"Next exercise: ")?;
             app_state
                 .current_exercise()

src/watch.rs

@@ -11,7 +11,10 @@ use std::{
     time::Duration,
 };
 
-use crate::app_state::{AppState, ExercisesProgress};
+use crate::{
+    app_state::{AppState, ExercisesProgress},
+    list,
+};
 
 use self::{
     notify_event::NotifyEventHandler,
@@ -26,22 +29,21 @@ mod terminal_event;
 enum WatchEvent {
     Input(InputEvent),
     FileChange { exercise_ind: usize },
-    TerminalResize,
+    TerminalResize { width: u16 },
     NotifyErr(notify::Error),
     TerminalEventErr(io::Error),
 }
 
 /// Returned by the watch mode to indicate what to do afterwards.
 #[must_use]
-pub enum WatchExit {
+enum WatchExit {
     /// Exit the program.
     Shutdown,
     /// Enter the list mode and restart the watch mode afterwards.
     List,
 }
 
-/// `notify_exercise_names` as None activates the manual run mode.
+fn run_watch(
-pub fn watch(
     app_state: &mut AppState,
     notify_exercise_names: Option<&'static [&'static [u8]]>,
 ) -> Result<WatchExit> {
@@ -70,7 +72,7 @@ pub fn watch(
         None
     };
 
-    let mut watch_state = WatchState::new(app_state, manual_run);
+    let mut watch_state = WatchState::build(app_state, manual_run)?;
 
     let mut stdout = io::stdout().lock();
     watch_state.run_current_exercise(&mut stdout)?;
@@ -81,26 +83,23 @@ pub fn watch(
         match event {
             WatchEvent::Input(InputEvent::Next) => match watch_state.next_exercise(&mut stdout)? {
                 ExercisesProgress::AllDone => break,
-                ExercisesProgress::CurrentPending => watch_state.render(&mut stdout)?,
                 ExercisesProgress::NewPending => watch_state.run_current_exercise(&mut stdout)?,
+                ExercisesProgress::CurrentPending => (),
             },
             WatchEvent::Input(InputEvent::Hint) => watch_state.show_hint(&mut stdout)?,
-            WatchEvent::Input(InputEvent::List) => {
+            WatchEvent::Input(InputEvent::List) => return Ok(WatchExit::List),
-                return Ok(WatchExit::List);
-            }
             WatchEvent::Input(InputEvent::Quit) => {
                 stdout.write_all(QUIT_MSG)?;
                 break;
             }
             WatchEvent::Input(InputEvent::Run) => watch_state.run_current_exercise(&mut stdout)?,
-            WatchEvent::Input(InputEvent::Unrecognized) => watch_state.render(&mut stdout)?,
             WatchEvent::FileChange { exercise_ind } => {
                 watch_state.handle_file_change(exercise_ind, &mut stdout)?;
             }
-            WatchEvent::TerminalResize => watch_state.render(&mut stdout)?,
+            WatchEvent::TerminalResize { width } => {
-            WatchEvent::NotifyErr(e) => {
+                watch_state.update_term_width(width, &mut stdout)?;
-                return Err(Error::from(e).context(NOTIFY_ERR));
             }
+            WatchEvent::NotifyErr(e) => return Err(Error::from(e).context(NOTIFY_ERR)),
             WatchEvent::TerminalEventErr(e) => {
                 return Err(Error::from(e).context("Terminal event listener failed"));
             }
@@ -110,6 +109,48 @@ pub fn watch(
     Ok(WatchExit::Shutdown)
 }
 
+fn watch_list_loop(
+    app_state: &mut AppState,
+    notify_exercise_names: Option<&'static [&'static [u8]]>,
+) -> Result<()> {
+    loop {
+        match run_watch(app_state, notify_exercise_names)? {
+            WatchExit::Shutdown => break Ok(()),
+            // It is much easier to exit the watch mode, launch the list mode and then restart
+            // the watch mode instead of trying to pause the watch threads and correct the
+            // watch state.
+            WatchExit::List => list::list(app_state)?,
+        }
+    }
+}
+
+/// `notify_exercise_names` as None activates the manual run mode.
+pub fn watch(
+    app_state: &mut AppState,
+    notify_exercise_names: Option<&'static [&'static [u8]]>,
+) -> Result<()> {
+    #[cfg(not(windows))]
+    {
+        let stdin_fd = rustix::stdio::stdin();
+        let mut termios = rustix::termios::tcgetattr(stdin_fd)?;
+        let original_local_modes = termios.local_modes;
+        // Disable stdin line buffering and hide input.
+        termios.local_modes -=
+            rustix::termios::LocalModes::ICANON | rustix::termios::LocalModes::ECHO;
+        rustix::termios::tcsetattr(stdin_fd, rustix::termios::OptionalActions::Now, &termios)?;
+
+        let res = watch_list_loop(app_state, notify_exercise_names);
+
+        termios.local_modes = original_local_modes;
+        rustix::termios::tcsetattr(stdin_fd, rustix::termios::OptionalActions::Now, &termios)?;
+
+        res
+    }
+
+    #[cfg(windows)]
+    watch_list_loop(app_state, notify_exercise_names)
+}
+
 const QUIT_MSG: &[u8] = b"
 We hope you're enjoying learning Rust!
 If you want to continue working on the exercises at a later point, you can simply run `rustlings` again.

src/watch/state.rs

@@ -1,4 +1,4 @@
-use anyhow::Result;
+use anyhow::{Context, Result};
 use crossterm::{
     style::{
         Attribute, Attributes, Color, ResetColor, SetAttribute, SetAttributes, SetForegroundColor,
@@ -27,17 +27,23 @@ pub struct WatchState<'a> {
     show_hint: bool,
     done_status: DoneStatus,
     manual_run: bool,
+    term_width: u16,
 }
 
 impl<'a> WatchState<'a> {
-    pub fn new(app_state: &'a mut AppState, manual_run: bool) -> Self {
+    pub fn build(app_state: &'a mut AppState, manual_run: bool) -> Result<Self> {
-        Self {
+        let term_width = terminal::size()
+            .context("Failed to get the terminal size")?
+            .0;
+
+        Ok(Self {
             app_state,
             output: Vec::with_capacity(OUTPUT_CAPACITY),
             show_hint: false,
             done_status: DoneStatus::Pending,
             manual_run,
-        }
+            term_width,
+        })
     }
 
     pub fn run_current_exercise(&mut self, stdout: &mut StdoutLock) -> Result<()> {
@@ -175,12 +181,11 @@ impl<'a> WatchState<'a> {
             )?;
         }
 
-        let line_width = terminal::size()?.0;
         progress_bar(
             stdout,
             self.app_state.n_done(),
             self.app_state.exercises().len() as u16,
-            line_width,
+            self.term_width,
         )?;
 
         stdout.write_all(b"\nCurrent exercise: ")?;
@@ -195,7 +200,20 @@ impl<'a> WatchState<'a> {
     }
 
     pub fn show_hint(&mut self, stdout: &mut StdoutLock) -> io::Result<()> {
-        self.show_hint = true;
+        if !self.show_hint {
-        self.render(stdout)
+            self.show_hint = true;
+            self.render(stdout)?;
+        }
+
+        Ok(())
+    }
+
+    pub fn update_term_width(&mut self, width: u16, stdout: &mut StdoutLock) -> io::Result<()> {
+        if self.term_width != width {
+            self.term_width = width;
+            self.render(stdout)?;
+        }
+
+        Ok(())
     }
 }

src/watch/terminal_event.rs

@@ -1,4 +1,4 @@
-use crossterm::event::{self, Event, KeyCode, KeyEventKind, KeyModifiers};
+use crossterm::event::{self, Event, KeyCode, KeyEventKind};
 use std::sync::mpsc::Sender;
 
 use super::WatchEvent;
@@ -9,13 +9,9 @@ pub enum InputEvent {
     Hint,
     List,
     Quit,
-    Unrecognized,
 }
 
 pub fn terminal_event_handler(tx: Sender<WatchEvent>, manual_run: bool) {
-    // Only send `Unrecognized` on ENTER if the last input wasn't valid.
-    let mut last_input_valid = false;
-
     let last_input_event = loop {
         let terminal_event = match event::read() {
             Ok(v) => v,
@@ -34,47 +30,21 @@ pub fn terminal_event_handler(tx: Sender<WatchEvent>, manual_run: bool) {
                     KeyEventKind::Press => (),
                 }
 
-                if key.modifiers != KeyModifiers::NONE {
-                    last_input_valid = false;
-                    continue;
-                }
-
                 let input_event = match key.code {
-                    KeyCode::Enter => {
+                    KeyCode::Char('n') => InputEvent::Next,
-                        if last_input_valid {
+                    KeyCode::Char('h') => InputEvent::Hint,
-                            continue;
+                    KeyCode::Char('l') => break InputEvent::List,
-                        }
+                    KeyCode::Char('q') => break InputEvent::Quit,
-
+                    KeyCode::Char('r') if manual_run => InputEvent::Run,
-                        InputEvent::Unrecognized
+                    _ => continue,
-                    }
-                    KeyCode::Char(c) => {
-                        let input_event = match c {
-                            'n' => InputEvent::Next,
-                            'h' => InputEvent::Hint,
-                            'l' => break InputEvent::List,
-                            'q' => break InputEvent::Quit,
-                            'r' if manual_run => InputEvent::Run,
-                            _ => {
-                                last_input_valid = false;
-                                continue;
-                            }
-                        };
-
-                        last_input_valid = true;
-                        input_event
-                    }
-                    _ => {
-                        last_input_valid = false;
-                        continue;
-                    }
                 };
 
                 if tx.send(WatchEvent::Input(input_event)).is_err() {
                     return;
                 }
             }
-            Event::Resize(_, _) => {
+            Event::Resize(width, _) => {
-                if tx.send(WatchEvent::TerminalResize).is_err() {
+                if tx.send(WatchEvent::TerminalResize { width }).is_err() {
                     return;
                 }
             }