crypto: Connect the room key discarding logic

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/DefaultCryptoService.kt

@@ -543,7 +543,7 @@ internal class DefaultCryptoService @Inject constructor(
     }
 
     override fun discardOutboundSession(roomId: String) {
-        // TODO
+        olmMachine?.discardRoomKey(roomId)
     }
 
     /**

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/OlmMachine.kt

@@ -496,4 +496,11 @@ internal class OlmMachine(user_id: String, device_id: String, path: File, device
 
         return devices
     }
+
+    /**
+     * Discard the currently active room key for the given room if there is one.
+     */
+    fun discardRoomKey(roomId: String) {
+        this.inner.discardRoomKey(roomId)
+    }
 }

rust-sdk/src/machine.rs

@@ -450,6 +450,14 @@ impl OlmMachine {
         })
     }
 
+    /// Discard the currently active room key for the given room if there is
+    /// one.
+    pub fn discard_room_key(&self, room_id: &str) {
+        let room_id = RoomId::try_from(room_id).unwrap();
+
+        self.inner.invalidate_group_session(&room_id);
+    }
+
     pub fn start_verification(&self, device: &Device) -> Result<Sas, CryptoStoreError> {
         let user_id = UserId::try_from(device.user_id.clone()).unwrap();
         let device_id = device.device_id.as_str().into();

rust-sdk/src/olm.udl

@@ -127,4 +127,5 @@ interface OlmMachine {
         [ByRef] string passphrase,
         ProgressListener progress_listener
     );
+    void discard_room_key([ByRef] string room_id);
 };