Implement third-party exercises trust handling

1 files changed, 42 insertions, 11 deletions

diff --git a/src/main.rs b/src/main.rs
index ed5becf..7b63f70 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,4 @@
 use anyhow::{Context, Result};
-use app_state::StateFileStatus;
 use clap::{Parser, Subcommand};
 use crossterm::{
     terminal::{Clear, ClearType},
@@ -19,14 +18,16 @@ mod init;
 mod list;
 mod progress_bar;
 mod run;
+mod trust;
 mod watch;
 
 use self::{
-    app_state::AppState,
+    app_state::{AppState, StateFileStatus},
     info_file::InfoFile,
     init::init,
     list::list,
     run::run,
+    trust::{current_dir_is_trusted, trust_current_dir},
     watch::{watch, WatchExit},
 };
 
@@ -61,6 +62,11 @@ enum Subcommands {
         /// The name of the exercise
         name: String,
     },
+    /// Trust the current directory with its exercises.
+    ///
+    /// You only need to run this if you want to work on third-party exercises or after you moved
+    /// the official exercises that were initialized with `rustlings init`.
+    Trust,
 }
 
 fn main() -> Result<()> {
@@ -72,14 +78,26 @@ fn main() -> Result<()> {
 
     if matches!(args.command, Some(Subcommands::Init)) {
         init(&info_file.exercises).context("Initialization failed")?;
-
         println!("{POST_INIT_MSG}");
         return Ok(());
-    } else if !Path::new("exercises").is_dir() {
+    }
+
+    if !Path::new("exercises").is_dir() {
         println!("{PRE_INIT_MSG}");
         exit(1);
     }
 
+    if matches!(args.command, Some(Subcommands::Trust)) {
+        trust_current_dir()?;
+        println!("{POST_TRUST_MSG}");
+        return Ok(());
+    }
+
+    if !current_dir_is_trusted()? {
+        println!("{NOT_TRUSTED_MSG}");
+        exit(1);
+    }
+
     let (mut app_state, state_file_status) = AppState::new(
         info_file.exercises,
         info_file.final_message.unwrap_or_default(),
@@ -130,8 +148,6 @@ fn main() -> Result<()> {
                 }
             }
         }
-        // `Init` is handled above.
-        Some(Subcommands::Init) => (),
         Some(Subcommands::Run { name }) => {
             if let Some(name) = name {
                 app_state.set_current_exercise_by_name(&name)?;
@@ -149,6 +165,8 @@ fn main() -> Result<()> {
             app_state.set_current_exercise_by_name(&name)?;
             println!("{}", app_state.current_exercise().hint);
         }
+        // `Init` and `Trust` are handled above.
+        Some(Subcommands::Init | Subcommands::Trust) => (),
     }
 
     Ok(())
@@ -158,8 +176,13 @@ const CARGO_NOT_FOUND_ERR: &str = "Failed to find `cargo`.
 Did you already install Rust?
 Try running `cargo --version` to diagnose the problem.";
 
+const POST_INIT_MSG: &str = "Done initialization!
+
+Run `cd rustlings` to go into the generated directory.
+Then run `rustlings` to get started.";
+
 const PRE_INIT_MSG: &str = r"
-       welcome to...
+       Welcome to...
                  _   _ _
   _ __ _   _ ___| |_| (_)_ __   __ _ ___
  | '__| | | / __| __| | | '_ \ / _` / __|
@@ -170,11 +193,19 @@ const PRE_INIT_MSG: &str = r"
 The `exercises` directory wasn't found in the current directory.
 If you are just starting with Rustlings, run the command `rustlings init` to initialize it.";
 
-const POST_INIT_MSG: &str = "
-Done initialization!
+const POST_TRUST_MSG: &str = "You now trust the exercises in the current directory.
+Run `rustlings` to start working on them.";
 
-Run `cd rustlings` to go into the generated directory.
-Then run `rustlings` to get started.";
+const NOT_TRUSTED_MSG: &str = "It looks like you are trying to work on third-party exercises.
+Rustlings supports third-party exercises. But because Rustlings runs the code inside an exercise,
+we need to warn you about the possibility of malicious code.
+We recommend that you read all the exercise files in the `exercises` directory and check the
+dependencies in the `Cargo.toml` file.
+If everything looks fine and you want to trust this directory, run `rustlings trust`.
+
+If you you are trying to work on the official exercises that were generated using `rustlings init`,
+then you probably moved the directory containing them. In that case, you can run `rustlings trust`
+without a problem.";
 
 const FENISH_LINE: &str = "+----------------------------------------------------+
 |          You made it to the Fe-nish line!          |