Only remove Android db listeners when all listened to events have been removed

Author: chrisbianca

android/src/main/java/io/fullstack/firestack/database/FirestackDatabase.java

@@ -171,14 +171,14 @@ public void onComplete(DatabaseError error, DatabaseReference ref) {
   public void on(final String path,
                  final String modifiersString,
                  final ReadableArray modifiersArray,
-                 final String name,
+                 final String eventName,
                  final Callback callback) {
     FirestackDatabaseReference ref = this.getDBHandle(path, modifiersArray, modifiersString);
 
-    if (name.equals("value")) {
+    if (eventName.equals("value")) {
       ref.addValueEventListener();
     } else {
-      ref.addChildEventListener(name);
+      ref.addChildEventListener(eventName);
     }
 
     WritableMap resp = Arguments.createMap();
@@ -191,7 +191,7 @@ public void on(final String path,
   public void onOnce(final String path,
                      final String modifiersString,
                      final ReadableArray modifiersArray,
-                     final String name,
+                     final String eventName,
                      final Callback callback) {
     FirestackDatabaseReference ref = this.getDBHandle(path, modifiersArray, modifiersString);
     ref.addOnceValueEventListener(callback);
@@ -207,22 +207,21 @@ public void onOnce(final String path,
   public void off(
           final String path,
           final String modifiersString,
-          final String name,
+          final String eventName,
           final Callback callback) {
 
     String key = this.getDBListenerKey(path, modifiersString);
     FirestackDatabaseReference r = mDBListeners.get(key);
 
     if (r != null) {
-      if (name == null || "".equals(name)) {
+      if (eventName == null || "".equals(eventName)) {
         r.cleanup();
         mDBListeners.remove(key);
       } else {
-        //TODO: Remove individual listeners as per iOS code
-        //1) Remove event handler
-        //2) If no more listeners, remove from listeners map
-        r.cleanup();
-        mDBListeners.remove(key);
+        r.removeEventListener(eventName);
+        if (!r.hasListeners()) {
+          mDBListeners.remove(key);
+        } ;
       }
     }
 

android/src/main/java/io/fullstack/firestack/database/FirestackDatabaseReference.java

@@ -1,8 +1,10 @@
 package io.fullstack.firestack.database;
 
+import java.util.HashSet;
 import java.util.List;
 import android.util.Log;
 import java.util.ListIterator;
+import java.util.Set;
 
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.Arguments;
@@ -28,6 +30,7 @@ public class FirestackDatabaseReference {
   private ChildEventListener mEventListener;
   private ValueEventListener mValueListener;
   private ReactContext mReactContext;
+  private Set<String> childEventListeners = new HashSet<>();
 
   public FirestackDatabaseReference(final ReactContext context,
                                     final FirebaseDatabase firebaseDatabase,
@@ -40,7 +43,7 @@ public FirestackDatabaseReference(final ReactContext context,
     mQuery = this.buildDatabaseQueryAtPathAndModifiers(firebaseDatabase, path, modifiersArray);
   }
 
-  public void addChildEventListener(final String name) {
+  public void addChildEventListener(final String eventName) {
     if (mEventListener == null) {
       mEventListener = new ChildEventListener() {
         @Override
@@ -65,14 +68,16 @@ public void onChildMoved(DataSnapshot dataSnapshot, String previousChildName) {
 
         @Override
         public void onCancelled(DatabaseError error) {
-          handleDatabaseError(name, error);
+          handleDatabaseError(eventName, error);
         }
       };
       mQuery.addChildEventListener(mEventListener);
       Log.d(TAG, "Added ChildEventListener for path: " + mPath + " with modifiers: "+ mModifiersString);
     } else {
       Log.w(TAG, "Trying to add duplicate ChildEventListener for path: " + mPath + " with modifiers: "+ mModifiersString);
     }
+    //Keep track of the events that the JS is interested in knowing about
+    childEventListeners.add(eventName);
   }
 
   public void addValueEventListener() {
@@ -117,8 +122,24 @@ public void onCancelled(DatabaseError error) {
     Log.d(TAG, "Added OnceValueEventListener for path: " + mPath + " with modifiers " + mModifiersString);
   }
 
+  public void removeEventListener(String eventName) {
+    if ("value".equals(eventName)) {
+      this.removeValueEventListener();
+    } else {
+      childEventListeners.remove(eventName);
+      if (childEventListeners.isEmpty()) {
+        this.removeChildEventListener();
+      }
+    }
+  }
+
+  public boolean hasListeners() {
+    return mEventListener != null || mValueListener != null;
+  }
+
   public void cleanup() {
     Log.d(TAG, "cleaning up database reference " + this);
+    childEventListeners.clear();
     this.removeChildEventListener();
     this.removeValueEventListener();
   }
@@ -272,5 +293,4 @@ private Query buildDatabaseQueryAtPathAndModifiers(final FirebaseDatabase fireba
 
     return query;
   }
-
 }