fix de-/serialization of Connection objects. Fixes VPN auto-restart on reboot due to always-on system settings or if system killed app due to low memory

2 files changed, 38 insertions, 0 deletions

diff --git a/app/src/main/java/de/blinkt/openvpn/core/connection/Connection.java b/app/src/main/java/de/blinkt/openvpn/core/connection/Connection.java
index a318e55d..4cb9c0c7 100644
--- a/app/src/main/java/de/blinkt/openvpn/core/connection/Connection.java
+++ b/app/src/main/java/de/blinkt/openvpn/core/connection/Connection.java
@@ -7,9 +7,12 @@ package de.blinkt.openvpn.core.connection;
 
 import android.text.TextUtils;
 
+import com.google.gson.annotations.JsonAdapter;
+
 import java.io.Serializable;
 import java.util.Locale;
 
+@JsonAdapter(ConnectionAdapter.class)
 public abstract class Connection implements Serializable, Cloneable {
     private String mServerName = "openvpn.example.com";
     private String mServerPort = "1194";
diff --git a/app/src/main/java/de/blinkt/openvpn/core/connection/ConnectionAdapter.java b/app/src/main/java/de/blinkt/openvpn/core/connection/ConnectionAdapter.java
new file mode 100644
index 00000000..335ef34c
--- /dev/null
+++ b/app/src/main/java/de/blinkt/openvpn/core/connection/ConnectionAdapter.java
@@ -0,0 +1,35 @@
+package de.blinkt.openvpn.core.connection;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+
+import java.lang.reflect.Type;
+
+// Adapter for Gson used to serialize and deserialize abstract Connection class, adds a property about the implemented class
+public class ConnectionAdapter implements JsonSerializer<Connection>, JsonDeserializer<Connection> {
+
+    public final static String META_TYPE = ConnectionAdapter.class.getSimpleName() + ".META_TYPE";
+    @Override
+    public Connection deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
+        JsonObject jsonObject = json.getAsJsonObject();
+        String className = jsonObject.get(META_TYPE).getAsString();
+        try {
+            Class<?> clz = Class.forName(className);
+            return context.deserialize(json, clz);
+        } catch (ClassNotFoundException e) {
+            throw new JsonParseException(e);
+        }
+    }
+
+    @Override
+    public JsonElement serialize(Connection src, Type typeOfSrc, JsonSerializationContext context) {
+         JsonElement json = context.serialize(src, src.getClass());
+         json.getAsJsonObject().addProperty(META_TYPE, src.getClass().getCanonicalName());
+         return json;
+    }
+}