Merge pull request #75 from triarius/triarius/error-report

Report error when word list is too short

src/main.rs

@@ -27,11 +27,9 @@ fn main() -> Result<()> {
     let mut words: Vec<String> = words::list(args.dict_path)?;
     let mut rng = rand::thread_rng();
 
-    print!(
-        "{}",
-        passphrase::new(&mut rng, &mut words, args.num_words, &args.separator)
-    );
+    let passphrase = passphrase::new(&mut rng, &mut words, args.num_words, &args.separator)?;
 
+    print!("{passphrase}");
     if std::io::stdout().is_terminal() {
         println!();
     }

src/passphrase.rs

@@ -1,24 +1,29 @@
+use eyre::{eyre, Result};
 use rand::Rng;
 
-pub fn new<T: Rng>(mut rng: T, words: &mut [String], num_words: usize, separator: &str) -> String {
+pub fn new<T: Rng>(
+    mut rng: T,
+    words: &mut [String],
+    num_words: usize,
+    separator: &str,
+) -> Result<String> {
     if words.len() < num_words {
-        eprintln!(
+        return Err(eyre!(
             "Your dictionary only has {} suitable words, but you asked for {} words.",
             words.len(),
             num_words
-        );
-        return String::new();
+        ));
     }
 
     (0..num_words).for_each(|i| {
         let j = rng.gen_range(i..words.len());
         words.swap(i, j);
     });
 
-    (0..num_words)
+    Ok((0..num_words)
         .map(|i| words[i].clone())
-        .collect::<Vec<String>>()
-        .join(separator)
+        .collect::<Vec<_>>()
+        .join(separator))
 }
 
 mod test {
@@ -66,17 +71,17 @@ mod test {
                 let mut rng = ChaCha8Rng::seed_from_u64(seed);
                 rng.set_stream(*i as u64);
                 let mut words = words.clone();
-                let s = passphrase::new(&mut rng, &mut words, W, " ");
+                let s = passphrase::new(&mut rng, &mut words, W, " ").unwrap();
                 *acc.entry(s).or_insert(0) += 1_usize;
                 acc
             })
             .collect::<Vec<HashMap<String, usize>>>()
             .iter()
-            .fold(HashMap::new(), |mut acc, h| {
-                for (k, v) in h {
+            .fold(HashMap::new(), |acc, h| {
+                h.iter().fold(acc, |mut acc, (k, v)| {
                     *acc.entry(k.to_owned()).or_insert(0) += v;
-                }
-                acc
+                    acc
+                })
             });
 
         assert_eq!(histogram.values().sum::<usize>(), N, "missing samples");