Adds a store_mut method to kademlia. (#1192)

* Adds a retain method to kademlia.

* Add a store_mut getter to Kademlia

* Removes a blank line

* Changes store_mut comment appropriately

* Fixes build

* Return a type, not a trait

protocols/kad/src/behaviour.rs

@@ -276,6 +276,11 @@ where
         }
     }
 
+    /// Get a mutable reference to internal record store.
+    pub fn store_mut(&mut self) -> &mut TStore {
+        &mut self.records
+    }
+
     /// Bootstraps the local node to join the DHT.
     ///
     /// Bootstrapping is a multi-step operation that starts with a lookup of the local node's

protocols/kad/src/record.rs

@@ -78,6 +78,15 @@ impl Default for MemoryRecordStorage {
     }
 }
 
+impl MemoryRecordStorage {
+    /// Retain the elements by a predicate.
+    pub fn retain<F>(&mut self, f: F)
+        where F: FnMut(&Multihash, &mut Record) -> bool
+    {
+        self.records.retain(f);
+    }
+}
+
 impl RecordStore for MemoryRecordStorage {
     fn get(&self, k: &Multihash) -> Option<Cow<Record>> {
         match self.records.get(k) {