Fix handling of SIGINT

Keep track of a new atomic variable: at_prompt, which is set to true
just before blocking on io::stdin.read_line, and set to false just
calling Poem::read. Additionally, for background tasks, there is a new
ps macro called btask, which changes the process group of commands that
are forked into the background, so that they don't receive SIGINT from
the keyboard.

1 files changed, 17 insertions, 4 deletions

diff --git a/src/main.rs b/src/main.rs
index 3cb2a74..04d58eb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ use recite::path::prefresh;
 use recite::Poem;
 use std::io::{self, Write};
 use std::path::Path;
+use std::sync::{Arc, Mutex};
 
 /// Starts the main shell loop
 ///
@@ -20,7 +21,7 @@ use std::path::Path;
 ///     repl(&path, prompt);
 /// }
 /// ```
-fn repl(path: &Vec<&Path>, prompt: &str) {
+fn repl(path: &Vec<&Path>, prompt: &str, at_prompt: &mut Arc<Mutex<bool>>) {
     // Initial path refresh on startup
     let mut bins: Vec<String> = prefresh(path);
 
@@ -30,6 +31,9 @@ fn repl(path: &Vec<&Path>, prompt: &str) {
         print!("{}", prompt);
         io::stdout().flush().unwrap();
 
+        // At the prompt
+        *at_prompt.lock().unwrap() = true;
+
         // Wait for user input
         let mut poetry = String::new();
         let bytes = io::stdin()
@@ -50,6 +54,9 @@ fn repl(path: &Vec<&Path>, prompt: &str) {
             continue;
         }
 
+        // Not at the prompt
+        *at_prompt.lock().unwrap() = false;
+
         // Parse a poem
         let poem = Poem::read(poetry);
         match poem {
@@ -80,16 +87,22 @@ fn main() {
 
     // Set the prompt
     let prompt = "|> ";
+    let mut at_prompt = Arc::new(Mutex::new(false));
 
     // Handle signals
     unsafe {
+        let at_prompt = Arc::clone(&at_prompt);
         signal_hook::low_level::register(signal_hook::consts::SIGINT, move || {
-            print!("\n{}", prompt);
-            io::stdout().flush().unwrap();
+            if *at_prompt.lock().unwrap() {
+                print!("\n{}", prompt);
+                io::stdout().flush().unwrap();
+            } else {
+                println!();
+            }
         })
         .unwrap();
     };
 
     // Begin evaluating commands
-    repl(&path, prompt);
+    repl(&path, prompt, &mut at_prompt);
 }