Ensure deserialization of previously stored objects still works

After package has been renamed from `im.vector.matrix.android` to `org.matrix.android.sdk`

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/store/db/Helper.kt

@@ -23,7 +23,6 @@ import io.realm.RealmConfiguration
 import io.realm.RealmObject
 import java.io.ByteArrayInputStream
 import java.io.ByteArrayOutputStream
-import java.io.ObjectInputStream
 import java.io.ObjectOutputStream
 import java.util.zip.GZIPInputStream
 
@@ -98,7 +97,7 @@ fun <T> deserializeFromRealm(string: String?): T? {
 
     val bais = ByteArrayInputStream(decodedB64)
     val gzis = GZIPInputStream(bais)
-    val ois = ObjectInputStream(gzis)
+    val ois = SafeObjectInputStream(gzis)
     return ois.use {
         it.readObject() as T
     }

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/store/db/SafeObjectInputStream.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2020 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.android.sdk.internal.crypto.store.db
+
+import java.io.IOException
+import java.io.InputStream
+import java.io.ObjectInputStream
+import java.io.ObjectStreamClass
+
+/**
+ * Package has been renamed from `im.vector.matrix.android` to `org.matrix.android.sdk`
+ * so ensure deserialization of previously stored objects still works
+ *
+ * Ref: https://stackoverflow.com/questions/3884492/how-can-i-change-package-for-a-bunch-of-java-serializable-classes
+ */
+internal class SafeObjectInputStream(`in`: InputStream) : ObjectInputStream(`in`) {
+
+    init {
+        enableResolveObject(true)
+    }
+
+    @Throws(IOException::class, ClassNotFoundException::class)
+    override fun readClassDescriptor(): ObjectStreamClass {
+        val read = super.readClassDescriptor()
+        if (read.name.startsWith("im.vector.matrix.android.")) {
+            return ObjectStreamClass.lookup(Class.forName(read.name.replace("im.vector.matrix.android.", "org.matrix.android.sdk.")))
+        }
+        return read
+    }
+}