keyfork-mnemonic-util: optimize Default::default() for Wordlist

crates/util/keyfork-mnemonic-util/src/lib.rs

@@ -48,19 +48,26 @@ impl Error for MnemonicGenerationError {}
 #[derive(Debug, Clone)]
 pub struct Wordlist(Vec<String>);
 
+static ENGLISH: OnceLock<Wordlist> = OnceLock::new();
+
 impl Default for Wordlist {
     /// Returns the English wordlist in the Bitcoin BIP-0039 specification.
     fn default() -> Self {
         // TODO: English is the only supported language.
-        let wordlist_file = include_str!("data/wordlist.txt");
-        Wordlist(
-            wordlist_file
-                .lines()
-                // skip 1: comment at top of file to point to BIP-0039 source.
-                .skip(1)
-                .map(|x| x.trim().to_string())
-                .collect(),
-        )
+        ENGLISH
+            .get_or_init(|| {
+                let wordlist_file = include_str!("data/wordlist.txt");
+                Wordlist(
+                    wordlist_file
+                        .lines()
+                        // skip 1: comment at top of file to point to BIP-0039 source.
+                        .skip(1)
+                        .map(|x| x.trim().to_string())
+                        .collect(),
+                )
+                .shrank()
+            })
+            .clone()
     }
 }
 
@@ -71,6 +78,12 @@ impl Wordlist {
         Arc::new(self)
     }
 
+    /// Return a shrank version of the Wordlist
+    pub fn shrank(mut self) -> Self {
+        self.0.shrink_to_fit();
+        self
+    }
+
     /// Determine whether the Wordlist contains a given word.
     pub fn contains(&self, word: &str) -> bool {
         self.0.iter().any(|w| w.as_str() == word)