aircrafts: Arc all the Strings

src/aircrafts.rs

@@ -1,13 +1,14 @@
 use std::collections::HashMap;
 use std::io::BufReader;
 use std::fs::File;
+use std::sync::Arc;
 use serde::Deserialize;
 
 #[derive(Debug)]
 pub struct Aircraft {
-    pub owner: Option<String>,
-    pub registration: Option<String>,
-    pub model: Option<String>,
+    pub owner: Option<Arc<String>>,
+    pub registration: Option<Arc<String>>,
+    pub model: Option<Arc<String>>,
 }
 
 #[derive(Debug, Deserialize)]
@@ -25,27 +26,30 @@ pub struct Aircrafts {
 
 impl Aircrafts {
     pub fn load(file: &str) -> Self {
-        let mut rdr = csv::Reader::from_reader(BufReader::new(File::open(file).unwrap()));
+        let mut strings = HashMap::new();
+        let mut nullable = move |s: String| {
+            if s.len() > 0 {
+                let e = strings.entry(s.clone())
+                    .or_insert_with(|| Arc::new(s));
+                Some(e.clone())
+            } else {
+                None
+            }
+        };
         let mut data = HashMap::new();
+        let mut rdr = csv::Reader::from_reader(BufReader::new(File::open(file).unwrap()));
         for result in rdr.deserialize() {
             let rec: Record = result.unwrap();
             if rec.registration != "" {
-                fn nullable(s: String) -> Option<String> {
-                    if s.len() > 0 {
-                        Some(s)
-                    } else {
-                        None
-                    }
-                }
                 data.insert(rec.icao24, Aircraft {
                     owner: nullable(rec.owner),
                     registration: nullable(rec.registration),
                     model: if rec.manufacturername == "" && rec.model == "" {
                         None
                     } else if rec.model.starts_with(&rec.manufacturername) {
-                        Some(rec.model)
+                        nullable(rec.model)
                     } else {
-                        Some(format!("{} {}", rec.manufacturername, rec.model))
+                        nullable(format!("{} {}", rec.manufacturername, rec.model))
                     },
                 });
             }