Begin work on cleaning up old nonces

src/lib.rs

@@ -321,6 +321,19 @@ pub async fn update_extra_infos(
 /// We store to-be-processed negative reports as a vector. Add this NR
 /// to that vector (or create a new vector if necessary)
 pub fn save_negative_report_to_process(db: &Db, nr: NegativeReport) {
+    // TODO: Purge these database entries sometimes
+    let mut nonces = match db.get(format!("nonces_{}", &nr.date)).unwrap() {
+        Some(v) => bincode::deserialize(&v).unwrap(),
+        None => HashSet::<[u8; 32]>::new(),
+    };
+
+    // Just ignore the report if we've seen the nonce before
+    if nonces.insert(nr.nonce) {
+        db.insert(
+            format!("nonces_{}", &nr.date),
+            bincode::serialize(&nonces).unwrap(),
+        )
+        .unwrap();
         let mut reports = match db.get("nrs-to-process").unwrap() {
             Some(v) => bincode::deserialize(&v).unwrap(),
             None => BTreeMap::<String, Vec<SerializableNegativeReport>>::new(),
@@ -345,6 +358,7 @@ pub fn save_negative_report_to_process(db: &Db, nr: NegativeReport) {
         // Commit changes to database
         db.insert("nrs-to-process", bincode::serialize(&reports).unwrap())
             .unwrap();
+    }
 }
 
 /// Sends a collection of negative reports to the Lox Authority and returns the