Refactor embedded files to add solutions

src/app_state.rs

@@ -11,11 +11,7 @@ use std::{
     process::{Command, Stdio},
 };
 
-use crate::{
-    embedded::{WriteStrategy, EMBEDDED_FILES},
-    exercise::Exercise,
-    info_file::ExerciseInfo,
-};
+use crate::{embedded::EMBEDDED_FILES, exercise::Exercise, info_file::ExerciseInfo};
 
 const STATE_FILE_NAME: &str = ".rustlings-state.txt";
 const BAD_INDEX_ERR: &str = "The current exercise index is higher than the number of exercises";
@@ -100,10 +96,15 @@ impl AppState {
 
                 exercise_info.name.shrink_to_fit();
                 let name = exercise_info.name.leak();
+                let dir = exercise_info.dir.map(|mut dir| {
+                    dir.shrink_to_fit();
+                    &*dir.leak()
+                });
 
                 let hint = exercise_info.hint.trim().to_owned();
 
                 Exercise {
+                    dir,
                     name,
                     path,
                     mode: exercise_info.mode,
@@ -181,10 +182,16 @@ impl AppState {
         Ok(())
     }
 
-    fn reset_path(&self, path: &str) -> Result<()> {
+    fn reset(&self, ind: usize, dir_name: Option<&str>, path: &str) -> Result<()> {
         if self.official_exercises {
             return EMBEDDED_FILES
-                .write_exercise_to_disk(path, WriteStrategy::Overwrite)
+                .write_exercise_to_disk(
+                    ind,
+                    dir_name.context(
+                        "Official exercises must be nested in the `exercises` directory",
+                    )?,
+                    path,
+                )
                 .with_context(|| format!("Failed to reset the exercise {path}"));
         }
 
@@ -209,11 +216,11 @@ impl AppState {
     }
 
     pub fn reset_current_exercise(&mut self) -> Result<&'static str> {
-        let path = self.current_exercise().path;
         self.set_pending(self.current_exercise_ind)?;
-        self.reset_path(path)?;
+        let exercise = self.current_exercise();
+        self.reset(self.current_exercise_ind, exercise.dir, exercise.path)?;
 
-        Ok(path)
+        Ok(exercise.path)
     }
 
     pub fn reset_exercise_by_ind(&mut self, exercise_ind: usize) -> Result<&'static str> {
@@ -221,11 +228,11 @@ impl AppState {
             bail!(BAD_INDEX_ERR);
         }
 
-        let path = self.exercises[exercise_ind].path;
         self.set_pending(exercise_ind)?;
-        self.reset_path(path)?;
+        let exercise = &self.exercises[exercise_ind];
+        self.reset(exercise_ind, exercise.dir, exercise.path)?;
 
-        Ok(path)
+        Ok(exercise.path)
     }
 
     fn next_pending_exercise_ind(&self) -> Option<usize> {

src/embedded.rs

@@ -1,9 +1,10 @@
 use std::{
-    fs::{create_dir, File, OpenOptions},
+    fs::{create_dir, OpenOptions},
     io::{self, Write},
-    path::Path,
 };
 
+use crate::info_file::ExerciseInfo;
+
 pub static EMBEDDED_FILES: EmbeddedFiles = rustlings_macros::include_files!();
 
 #[derive(Clone, Copy)]
@@ -13,107 +14,78 @@ pub enum WriteStrategy {
 }
 
 impl WriteStrategy {
-    fn open<P: AsRef<Path>>(self, path: P) -> io::Result<File> {
-        match self {
+    fn write(self, path: &str, content: &[u8]) -> io::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?.write_all(content)
     }
 }
 
-struct EmbeddedFile {
-    path: &'static str,
-    content: &'static [u8],
+struct ExerciseFiles {
+    exercise: &'static [u8],
+    solution: &'static [u8],
 }
 
-impl EmbeddedFile {
-    fn write_to_disk(&self, strategy: WriteStrategy) -> io::Result<()> {
-        strategy.open(self.path)?.write_all(self.content)
-    }
+struct ExerciseDir {
+    name: &'static str,
+    readme: &'static [u8],
 }
 
-struct EmbeddedFlatDir {
-    path: &'static str,
-    readme: EmbeddedFile,
-    content: &'static [EmbeddedFile],
-}
-
-impl EmbeddedFlatDir {
+impl ExerciseDir {
     fn init_on_disk(&self) -> io::Result<()> {
-        let path = Path::new(self.path);
-
-        if let Err(e) = create_dir(path) {
-            if e.kind() != io::ErrorKind::AlreadyExists {
-                return Err(e);
+        if let Err(e) = create_dir(format!("exercises/{}", self.name)) {
+            if e.kind() == io::ErrorKind::AlreadyExists {
+                return Ok(());
             }
+
+            return Err(e);
         }
 
-        self.readme.write_to_disk(WriteStrategy::Overwrite)
+        WriteStrategy::Overwrite.write(&format!("exercises/{}/README.md", self.name), self.readme)
     }
 }
 
-struct ExercisesDir {
-    readme: EmbeddedFile,
-    files: &'static [EmbeddedFile],
-    dirs: &'static [EmbeddedFlatDir],
-}
-
 pub struct EmbeddedFiles {
-    exercises_dir: ExercisesDir,
+    exercise_files: &'static [ExerciseFiles],
+    exercise_dirs: &'static [ExerciseDir],
 }
 
 impl EmbeddedFiles {
-    pub fn init_exercises_dir(&self) -> io::Result<()> {
+    pub fn init_exercises_dir(&self, exercise_infos: &[ExerciseInfo]) -> io::Result<()> {
         create_dir("exercises")?;
 
-        self.exercises_dir
-            .readme
-            .write_to_disk(WriteStrategy::IfNotExists)?;
+        WriteStrategy::IfNotExists.write(
+            "exercises/README.md",
+            include_bytes!("../exercises/README.md"),
+        )?;
 
-        for file in self.exercises_dir.files {
-            file.write_to_disk(WriteStrategy::IfNotExists)?;
+        for dir in self.exercise_dirs {
+            dir.init_on_disk()?;
         }
 
-        for dir in self.exercises_dir.dirs {
-            dir.init_on_disk()?;
-
-            for file in dir.content {
-                file.write_to_disk(WriteStrategy::IfNotExists)?;
-            }
+        for (exercise_info, exercise_files) in exercise_infos.iter().zip(self.exercise_files) {
+            WriteStrategy::IfNotExists.write(&exercise_info.path(), exercise_files.exercise)?;
         }
 
         Ok(())
     }
 
-    pub fn write_exercise_to_disk<P>(&self, path: P, strategy: WriteStrategy) -> io::Result<()>
-    where
-        P: AsRef<Path>,
-    {
-        let path = path.as_ref();
+    pub fn write_exercise_to_disk(&self, exercise_ind: usize, dir_name: &str, path: &str) -> io::Result<()> {
+        let Some(dir) = self.exercise_dirs.iter().find(|dir| dir.name == dir_name) else {
+            return Err(io::Error::new(
+                io::ErrorKind::NotFound,
+                format!("`{dir_name}` not found in the embedded directories"),
+            ));
+        };
 
-        if let Some(file) = self
-            .exercises_dir
-            .files
-            .iter()
-            .find(|file| Path::new(file.path) == path)
-        {
-            return file.write_to_disk(strategy);
-        }
-
-        for dir in self.exercises_dir.dirs {
-            if let Some(file) = dir.content.iter().find(|file| Path::new(file.path) == path) {
-                dir.init_on_disk()?;
-                return file.write_to_disk(strategy);
-            }
-        }
-
-        Err(io::Error::new(
-            io::ErrorKind::NotFound,
-            format!("{} not found in the embedded files", path.display()),
-        ))
+        dir.init_on_disk()?;
+        WriteStrategy::Overwrite.write(path, self.exercise_files[exercise_ind].exercise)
     }
 }

src/exercise.rs

@@ -31,6 +31,7 @@ impl<'a> Display for TerminalFileLink<'a> {
 }
 
 pub struct Exercise {
+    pub dir: Option<&'static str>,
     // Exercise's unique name
     pub name: &'static str,
     // Exercise's path

src/init.rs

@@ -24,11 +24,11 @@ pub fn init() -> Result<()> {
     set_current_dir("rustlings")
         .context("Failed to change the current directory to `rustlings`")?;
 
+    let info_file = InfoFile::parse()?;
     EMBEDDED_FILES
-        .init_exercises_dir()
+        .init_exercises_dir(&info_file.exercises)
         .context("Failed to initialize the `rustlings/exercises` directory")?;
 
-    let info_file = InfoFile::parse()?;
     let current_cargo_toml = include_str!("../dev/Cargo.toml");
     // Skip the first line (comment).
     let newline_ind = current_cargo_toml