Room Tag Comparator : use a separate class and probably fix a crash

CHANGES.rst

@@ -19,6 +19,7 @@ Bugfix:
  - Add API CallSoundsManager.startRingingSilently() to fix issue when incoming call sound is disable (vector-im/riot-android#2417)
  - Use same TxId when resending an event. The eventId is used as a TxId. (vector-im/riot-android#1997)
  - Fix bad bing on '@room' pattern. (vector-im/riot-android#2461)
+ - Fix Crash loop reported by RageShake (vector-im/riot-android#2501)
 
 API Change:
  - Parameter historyVisibility removed from MxSession.createRoom(). It had no effect.

matrix-sdk/src/main/java/org/matrix/androidsdk/MXSession.java

@@ -38,6 +38,7 @@
 import org.matrix.androidsdk.data.RoomState;
 import org.matrix.androidsdk.data.RoomSummary;
 import org.matrix.androidsdk.data.RoomTag;
+import org.matrix.androidsdk.data.comparator.RoomComparatorWithTag;
 import org.matrix.androidsdk.data.cryptostore.IMXCryptoStore;
 import org.matrix.androidsdk.data.cryptostore.MXFileCryptoStore;
 import org.matrix.androidsdk.data.metrics.MetricsListener;
@@ -1575,61 +1576,25 @@ public boolean isVoipCallSupported() {
      * @return the rooms list.
      */
     public List<Room> roomsWithTag(final String tag) {
-        List<Room> taggedRooms = new ArrayList<>();
+        final List<Room> taggedRooms = new ArrayList<>();
 
         // sanity check
         if (null == mDataHandler.getStore()) {
             return taggedRooms;
         }
 
         if (!TextUtils.equals(tag, RoomTag.ROOM_TAG_NO_TAG)) {
-            Collection<Room> rooms = mDataHandler.getStore().getRooms();
-
+            final Collection<Room> rooms = mDataHandler.getStore().getRooms();
             for (Room room : rooms) {
                 if (null != room.getAccountData().roomTag(tag)) {
                     taggedRooms.add(room);
                 }
             }
-
             if (taggedRooms.size() > 0) {
-                Collections.sort(taggedRooms, new Comparator<Room>() {
-                    @Override
-                    public int compare(Room r1, Room r2) {
-                        int res = 0;
-
-                        RoomTag tag1 = r1.getAccountData().roomTag(tag);
-                        RoomTag tag2 = r2.getAccountData().roomTag(tag);
-
-                        if ((null != tag1.mOrder) && (null != tag2.mOrder)) {
-                            double diff = (tag1.mOrder - tag2.mOrder);
-                            res = (diff == 0) ? 0 : (diff > 0) ? +1 : -1;
-                        } else if (null != tag1.mOrder) {
-                            res = -1;
-                        } else if (null != tag2.mOrder) {
-                            res = +1;
-                        }
-
-                        // In case of same order, order rooms by their last event
-                        if (0 == res) {
-                            IMXStore store = mDataHandler.getStore();
-
-                            Event latestEvent1 = store.getLatestEvent(r1.getRoomId());
-                            Event latestEvent2 = store.getLatestEvent(r2.getRoomId());
-
-                            // sanity check
-                            if ((null != latestEvent2) && (null != latestEvent1)) {
-                                long diff = (latestEvent2.getOriginServerTs() - latestEvent1.getOriginServerTs());
-                                res = (diff == 0) ? 0 : (diff > 0) ? +1 : -1;
-                            }
-                        }
-
-                        return res;
-                    }
-                });
+                Collections.sort(taggedRooms, new RoomComparatorWithTag(tag));
             }
         } else {
-            Collection<Room> rooms = mDataHandler.getStore().getRooms();
-
+            final Collection<Room> rooms = mDataHandler.getStore().getRooms();
             for (Room room : rooms) {
                 if (!room.getAccountData().hasTags()) {
                     taggedRooms.add(room);

matrix-sdk/src/main/java/org/matrix/androidsdk/data/comparator/RoomComparatorWithTag.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2018 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.matrix.androidsdk.data.comparator;
+
+import org.matrix.androidsdk.data.Room;
+import org.matrix.androidsdk.data.RoomTag;
+
+import java.util.Comparator;
+
+/**
+ * This class is responsible for comparing rooms by the tag's order
+ */
+public class RoomComparatorWithTag implements Comparator<Room> {
+
+    private final String mTag;
+
+    public RoomComparatorWithTag(final String tag) {
+        mTag = tag;
+    }
+
+    @Override
+    public int compare(final Room r1, final Room r2) {
+        final int res;
+        final RoomTag tag1 = r1.getAccountData().roomTag(mTag);
+        final RoomTag tag2 = r2.getAccountData().roomTag(mTag);
+
+        if (tag1.mOrder != null && tag2.mOrder != null) {
+            res = Double.compare(tag1.mOrder, tag2.mOrder);
+        } else if (tag1.mOrder != null) {
+            res = 1;
+        } else {
+            res = -1;
+        }
+        return res;
+    }
+}