Add "dev update"

7 files changed, 178 insertions, 61 deletions

diff --git a/src/dev.rs b/src/dev.rs
index 7905f38..feca99e 100644
--- a/src/dev.rs
+++ b/src/dev.rs
@@ -1,22 +1,23 @@
 use anyhow::{Context, Result};
 use clap::Subcommand;
 
-use crate::info_file::InfoFile;
-
 mod check;
 mod init;
+mod update;
 
 #[derive(Subcommand)]
 pub enum DevCommands {
     Init,
     Check,
+    Update,
 }
 
 impl DevCommands {
-    pub fn run(self, info_file: InfoFile) -> Result<()> {
+    pub fn run(self) -> Result<()> {
         match self {
             DevCommands::Init => init::init().context(INIT_ERR),
-            DevCommands::Check => check::check(info_file),
+            DevCommands::Check => check::check(),
+            DevCommands::Update => update::update(),
         }
     }
 }
diff --git a/src/dev/check.rs b/src/dev/check.rs
index 5910a75..bc8e459 100644
--- a/src/dev/check.rs
+++ b/src/dev/check.rs
@@ -1,16 +1,83 @@
+use anyhow::{bail, Context, Result};
 use std::fs;
 
-use anyhow::{Context, Result};
+use crate::{
+    info_file::{ExerciseInfo, InfoFile},
+    DEVELOPING_OFFIFICAL_RUSTLINGS,
+};
 
-use crate::{info_file::InfoFile, init::cargo_toml};
+pub fn bins_start_end_ind(cargo_toml: &str) -> Result<(usize, usize)> {
+    let start_ind = cargo_toml
+        .find("bin = [")
+        .context("Failed to find the start of the `bin` list (`bin = [`)")?
+        + 7;
+    let end_ind = start_ind
+        + cargo_toml
+            .get(start_ind..)
+            .and_then(|slice| slice.as_bytes().iter().position(|c| *c == b']'))
+            .context("Failed to find the end of the `bin` list (`]`)")?;
+
+    Ok((start_ind, end_ind))
+}
+
+pub fn append_bins(
+    buf: &mut Vec<u8>,
+    exercise_infos: &[ExerciseInfo],
+    exercise_path_prefix: &[u8],
+) {
+    buf.push(b'\n');
+    for exercise_info in exercise_infos {
+        buf.extend_from_slice(b"  { name = \"");
+        buf.extend_from_slice(exercise_info.name.as_bytes());
+        buf.extend_from_slice(b"\", path = \"");
+        buf.extend_from_slice(exercise_path_prefix);
+        buf.extend_from_slice(b"exercises/");
+        if let Some(dir) = &exercise_info.dir {
+            buf.extend_from_slice(dir.as_bytes());
+            buf.push(b'/');
+        }
+        buf.extend_from_slice(exercise_info.name.as_bytes());
+        buf.extend_from_slice(b".rs\" },\n");
+    }
+}
+
+fn check_cargo_toml(
+    exercise_infos: &[ExerciseInfo],
+    current_cargo_toml: &str,
+    exercise_path_prefix: &[u8],
+) -> Result<()> {
+    let (bins_start_ind, bins_end_ind) = bins_start_end_ind(current_cargo_toml)?;
+
+    let old_bins = &current_cargo_toml.as_bytes()[bins_start_ind..bins_end_ind];
+    let mut new_bins = Vec::with_capacity(1 << 13);
+    append_bins(&mut new_bins, exercise_infos, exercise_path_prefix);
+
+    if old_bins != new_bins {
+        bail!("`Cargo.toml` is outdated. Run `rustlings dev update` to update it");
+    }
+
+    Ok(())
+}
+
+pub fn check() -> Result<()> {
+    let info_file = InfoFile::parse()?;
 
-pub fn check(info_file: InfoFile) -> Result<()> {
     // TODO: Add checks
 
-    // TODO: Keep dependencies!
-    fs::write("Cargo.toml", cargo_toml(&info_file.exercises))
-        .context("Failed to update the file `Cargo.toml`")?;
-    println!("Updated `Cargo.toml`");
+    if DEVELOPING_OFFIFICAL_RUSTLINGS {
+        check_cargo_toml(
+            &info_file.exercises,
+            include_str!("../../dev/Cargo.toml"),
+            b"../",
+        )
+        .context("The file `dev/Cargo.toml` is outdated. Please run `cargo run -- dev update` to update it")?;
+    } else {
+        let current_cargo_toml =
+            fs::read_to_string("Cargo.toml").context("Failed to read the file `Cargo.toml`")?;
+        check_cargo_toml(&info_file.exercises, &current_cargo_toml, b"").context(
+            "The file `Cargo.toml` is outdated. Please run `rustlings dev update` to update it",
+        )?;
+    }
 
     println!("\nEverything looks fine!");
 
diff --git a/src/dev/init.rs b/src/dev/init.rs
index 0993522..3ce5055 100644
--- a/src/dev/init.rs
+++ b/src/dev/init.rs
@@ -1,6 +1,5 @@
-use std::fs::{self, create_dir};
-
 use anyhow::{Context, Result};
+use std::fs::{self, create_dir};
 
 use crate::CURRENT_FORMAT_VERSION;
 
@@ -19,11 +18,8 @@ pub fn init() -> Result<()> {
     )
     .context("Failed to create the file `rustlings/info.toml`")?;
 
-    fs::write(
-        "rustlings/Cargo.toml",
-        format!("{CARGO_TOML_COMMENT}{}", crate::init::CARGO_TOML_PACKAGE),
-    )
-    .context("Failed to create the file `rustlings/Cargo.toml`")?;
+    fs::write("rustlings/Cargo.toml", CARGO_TOML)
+        .context("Failed to create the file `rustlings/Cargo.toml`")?;
 
     fs::write("rustlings/.gitignore", crate::init::GITIGNORE)
         .context("Failed to create the file `rustlings/.gitignore`")?;
@@ -80,10 +76,17 @@ mode = "test"
 hint = """???"""
 "#;
 
-const CARGO_TOML_COMMENT: &str =
-    "# You shouldn't edit this file manually! It is updated by `rustlings dev check`
+const CARGO_TOML: &[u8] =
+    br#"# Don't edit the `bin` list manually! It is updated by `rustlings dev update`
+bin = []
 
-";
+[package]
+name = "rustlings"
+edition = "2021"
+publish = false
+
+[dependencies]
+"#;
 
 const README: &str = "# Rustlings 🦀
 
diff --git a/src/dev/update.rs b/src/dev/update.rs
new file mode 100644
index 0000000..981934d
--- /dev/null
+++ b/src/dev/update.rs
@@ -0,0 +1,53 @@
+use std::fs;
+
+use anyhow::{Context, Result};
+
+use crate::{
+    info_file::{ExerciseInfo, InfoFile},
+    DEVELOPING_OFFIFICAL_RUSTLINGS,
+};
+
+use super::check::{append_bins, bins_start_end_ind};
+
+fn update_cargo_toml(
+    exercise_infos: &[ExerciseInfo],
+    current_cargo_toml: &str,
+    cargo_toml_path: &str,
+    exercise_path_prefix: &[u8],
+) -> Result<()> {
+    let (bins_start_ind, bins_end_ind) = bins_start_end_ind(current_cargo_toml)?;
+
+    let mut new_cargo_toml = Vec::with_capacity(1 << 13);
+    new_cargo_toml.extend_from_slice(current_cargo_toml[..bins_start_ind].as_bytes());
+    append_bins(&mut new_cargo_toml, exercise_infos, exercise_path_prefix);
+    new_cargo_toml.extend_from_slice(current_cargo_toml[bins_end_ind..].as_bytes());
+
+    fs::write(cargo_toml_path, new_cargo_toml).context("Failed to write the `Cargo.toml` file")?;
+
+    Ok(())
+}
+
+pub fn update() -> Result<()> {
+    let info_file = InfoFile::parse()?;
+
+    if DEVELOPING_OFFIFICAL_RUSTLINGS {
+        update_cargo_toml(
+            &info_file.exercises,
+            include_str!("../../dev/Cargo.toml"),
+            "dev/Cargo.toml",
+            b"../",
+        )
+        .context("Failed to update the file `dev/Cargo.toml`")?;
+
+        println!("Updated `dev/Cargo.toml`");
+    } else {
+        let current_cargo_toml =
+            fs::read_to_string("Cargo.toml").context("Failed to read the file `Cargo.toml`")?;
+        update_cargo_toml(&info_file.exercises, &current_cargo_toml, "Cargo.toml", b"")
+            .context("Failed to update the file `Cargo.toml`")?;
+
+        println!("Updated `Cargo.toml`");
+    }
+
+    Ok(())
+}
diff --git a/src/exercise.rs b/src/exercise.rs
index 8bdf399..c4df999 100644
--- a/src/exercise.rs
+++ b/src/exercise.rs
@@ -9,6 +9,7 @@ use std::{
 use crate::{
     embedded::{WriteStrategy, EMBEDDED_FILES},
     info_file::Mode,
+    DEVELOPING_OFFIFICAL_RUSTLINGS,
 };
 
 pub struct TerminalFileLink<'a> {
@@ -50,9 +51,7 @@ impl Exercise {
         cmd.arg(command);
 
         // A hack to make `cargo run` work when developing Rustlings.
-        // Use `dev/Cargo.toml` when in the directory of the repository.
-        #[cfg(debug_assertions)]
-        if std::path::Path::new("tests").exists() {
+        if DEVELOPING_OFFIFICAL_RUSTLINGS {
             cmd.arg("--manifest-path").arg("dev/Cargo.toml");
         }
 
diff --git a/src/init.rs b/src/init.rs
index 5fa44d4..52315e2 100644
--- a/src/init.rs
+++ b/src/init.rs
@@ -6,30 +6,19 @@ use std::{
     path::Path,
 };
 
-use crate::{embedded::EMBEDDED_FILES, info_file::ExerciseInfo};
-
-pub fn cargo_toml(exercise_infos: &[ExerciseInfo]) -> Vec<u8> {
-    let mut cargo_toml = Vec::with_capacity(1 << 13);
-    cargo_toml.extend_from_slice(b"bin = [\n");
-    for exercise_info in exercise_infos {
-        cargo_toml.extend_from_slice(b"  { name = \"");
-        cargo_toml.extend_from_slice(exercise_info.name.as_bytes());
-        cargo_toml.extend_from_slice(b"\", path = \"exercises/");
-        if let Some(dir) = &exercise_info.dir {
-            cargo_toml.extend_from_slice(dir.as_bytes());
-            cargo_toml.push(b'/');
-        }
-        cargo_toml.extend_from_slice(exercise_info.name.as_bytes());
-        cargo_toml.extend_from_slice(b".rs\" },\n");
+use crate::embedded::EMBEDDED_FILES;
+
+const CARGO_TOML: &[u8] = {
+    let cargo_toml = include_bytes!("../dev/Cargo.toml");
+    // Skip the first line (comment).
+    let mut start_ind = 0;
+    while cargo_toml[start_ind] != b'\n' {
+        start_ind += 1;
     }
+    cargo_toml.split_at(start_ind + 1).1
+};
 
-    cargo_toml.extend_from_slice(b"]\n\n");
-    cargo_toml.extend_from_slice(CARGO_TOML_PACKAGE.as_bytes());
-
-    cargo_toml
-}
-
-pub fn init(exercise_infos: &[ExerciseInfo]) -> Result<()> {
+pub fn init() -> Result<()> {
     if Path::new("exercises").is_dir() && Path::new("Cargo.toml").is_file() {
         bail!(PROBABLY_IN_RUSTLINGS_DIR_ERR);
     }
@@ -49,7 +38,7 @@ pub fn init(exercise_infos: &[ExerciseInfo]) -> Result<()> {
         .init_exercises_dir()
         .context("Failed to initialize the `rustlings/exercises` directory")?;
 
-    fs::write("Cargo.toml", cargo_toml(exercise_infos))
+    fs::write("Cargo.toml", CARGO_TOML)
         .context("Failed to create the file `rustlings/Cargo.toml`")?;
 
     fs::write(".gitignore", GITIGNORE)
@@ -64,12 +53,6 @@ pub fn init(exercise_infos: &[ExerciseInfo]) -> Result<()> {
     Ok(())
 }
 
-pub const CARGO_TOML_PACKAGE: &str = r#"[package]
-name = "rustlings"
-edition = "2021"
-publish = false
-"#;
-
 pub const GITIGNORE: &[u8] = b"Cargo.lock
 .rustlings-state.txt
 target
diff --git a/src/main.rs b/src/main.rs
index 8b3f28f..ea5f7c9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -25,6 +25,17 @@ mod watch;
 use self::{app_state::AppState, dev::DevCommands, info_file::InfoFile, watch::WatchExit};
 
 const CURRENT_FORMAT_VERSION: u8 = 1;
+const DEVELOPING_OFFIFICAL_RUSTLINGS: bool = {
+    #[allow(unused_assignments, unused_mut)]
+    let mut debug_profile = false;
+
+    #[cfg(debug_assertions)]
+    {
+        debug_profile = true;
+    }
+
+    debug_profile
+};
 
 /// Rustlings is a collection of small exercises to get you used to writing and reading Rust code
 #[derive(Parser)]
@@ -66,17 +77,11 @@ fn main() -> Result<()> {
 
     which::which("cargo").context(CARGO_NOT_FOUND_ERR)?;
 
-    let info_file = InfoFile::parse()?;
-
-    if info_file.format_version > CURRENT_FORMAT_VERSION {
-        bail!(FORMAT_VERSION_HIGHER_ERR);
-    }
-
     match args.command {
         Some(Subcommands::Init) => {
-            return init::init(&info_file.exercises).context("Initialization failed");
+            return init::init().context("Initialization failed");
         }
-        Some(Subcommands::Dev(dev_command)) => return dev_command.run(info_file),
+        Some(Subcommands::Dev(dev_command)) => return dev_command.run(),
         _ => (),
     }
 
@@ -85,6 +90,12 @@ fn main() -> Result<()> {
         exit(1);
     }
 
+    let info_file = InfoFile::parse()?;
+
+    if info_file.format_version > CURRENT_FORMAT_VERSION {
+        bail!(FORMAT_VERSION_HIGHER_ERR);
+    }
+
     let (mut app_state, state_file_status) = AppState::new(
         info_file.exercises,
         info_file.final_message.unwrap_or_default(),