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fix(database): refactor "removeObserver" to fix memory leak #2717

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Merged
merged 6 commits into from
Apr 21, 2021
Merged

fix(database): refactor "removeObserver" to fix memory leak #2717

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25d8245
Refactor "removeObserver" and remove memory leak
ened Jun 7, 2020
0dacdbe
Formatting
ened Jun 8, 2020
907fd3e
re-add the removeObserver parameters as iOS depends on it currently
ened Jun 8, 2020
7c546f7
Merge branch 'master' into firebase_database_memory_leak
Salakar Apr 21, 2021
ad8a442
Merge branch 'master' into firebase_database_memory_leak
ened Apr 21, 2021
802d5f5
Merge branch 'firebase_database_memory_leak' of github.com:ened/flutt…
ened Apr 21, 2021
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24 changes: 21 additions & 3 deletions ...se/android/src/main/java/io/flutter/plugins/firebase/database/FirebaseDatabasePlugin.java
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Original file line number Diff line number Diff line change
Expand Up @@ -8,21 +8,33 @@
import io.flutter.plugin.common.BinaryMessenger;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugin.common.PluginRegistry.ViewDestroyListener;
import io.flutter.view.FlutterNativeView;

/** FirebaseDatabasePlugin */
public class FirebaseDatabasePlugin implements FlutterPlugin {

private MethodChannel channel;
private MethodCallHandlerImpl methodCallHandler;

public static void registerWith(PluginRegistry.Registrar registrar) {
FirebaseDatabasePlugin plugin = new FirebaseDatabasePlugin();
final FirebaseDatabasePlugin plugin = new FirebaseDatabasePlugin();
plugin.setupMethodChannel(registrar.messenger());

registrar.addViewDestroyListener(
new ViewDestroyListener() {
@Override
public boolean onViewDestroy(FlutterNativeView view) {
plugin.cleanup();
return false;
}
});
}

private void setupMethodChannel(BinaryMessenger messenger) {
channel = new MethodChannel(messenger, "plugins.flutter.io/firebase_database");
MethodCallHandlerImpl handler = new MethodCallHandlerImpl(channel);
channel.setMethodCallHandler(handler);
methodCallHandler = new MethodCallHandlerImpl(channel);
channel.setMethodCallHandler(methodCallHandler);
}

@Override
Expand All @@ -32,6 +44,12 @@ public void onAttachedToEngine(FlutterPluginBinding binding) {

@Override
public void onDetachedFromEngine(FlutterPluginBinding binding) {
cleanup();
}

private void cleanup() {
methodCallHandler.cleanup();
methodCallHandler = null;
channel.setMethodCallHandler(null);
}
}
46 changes: 37 additions & 9 deletions ...ase/android/src/main/java/io/flutter/plugins/firebase/database/MethodCallHandlerImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -53,18 +53,37 @@ class MethodCallHandlerImpl implements MethodChannel.MethodCallHandler {
this.channel = channel;
}

void cleanup() {
final int size = observers.size();
for (int i = 0; i < size; i++) {
final EventObserver observer = observers.valueAt(i);
final Query query = observer.query;
if (observer.requestedEventType.equals(EVENT_TYPE_VALUE)) {
query.removeEventListener((ValueEventListener) observer);
} else {
query.removeEventListener((ChildEventListener) observer);
}
}

observers.clear();
}

private DatabaseReference getReference(FirebaseDatabase database, Map<String, Object> arguments) {
String path = (String) arguments.get("path");
DatabaseReference reference = database.getReference();
if (path != null) reference = reference.child(path);
if (path != null) {
reference = reference.child(path);
}
return reference;
}

private Query getQuery(FirebaseDatabase database, Map<String, Object> arguments) {
Query query = getReference(database, arguments);
@SuppressWarnings("unchecked")
Map<String, Object> parameters = (Map<String, Object>) arguments.get("parameters");
if (parameters == null) return query;
if (parameters == null) {
return query;
}
Object orderBy = parameters.get("orderBy");
if ("child".equals(orderBy)) {
query = query.orderByChild((String) parameters.get("orderByChildKey"));
Expand Down Expand Up @@ -148,6 +167,7 @@ private Query getQuery(FirebaseDatabase database, Map<String, Object> arguments)
}

private class DefaultCompletionListener implements DatabaseReference.CompletionListener {

private final MethodChannel.Result result;

DefaultCompletionListener(MethodChannel.Result result) {
Expand All @@ -164,12 +184,17 @@ public void onComplete(@Nullable DatabaseError error, @NonNull DatabaseReference
}
}

private class EventObserver implements ChildEventListener, ValueEventListener {
private static class EventObserver implements ChildEventListener, ValueEventListener {

private MethodChannel channel;
private String requestedEventType;
private Query query;
private int handle;

EventObserver(String requestedEventType, int handle) {
EventObserver(MethodChannel channel, String requestedEventType, Query query, int handle) {
this.channel = channel;
this.requestedEventType = requestedEventType;
this.query = query;
this.handle = handle;
}

Expand Down Expand Up @@ -249,6 +274,7 @@ public void onMethodCall(final MethodCall call, @NonNull final MethodChannel.Res
} else {
database = FirebaseDatabase.getInstance();
}

switch (call.method) {
case "FirebaseDatabase#goOnline":
{
Expand Down Expand Up @@ -347,7 +373,8 @@ public void onMethodCall(final MethodCall call, @NonNull final MethodChannel.Res
@NonNull
@Override
public Transaction.Result doTransaction(@NonNull MutableData mutableData) {
// Tasks are used to allow native execution of doTransaction to wait while Snapshot is
// Tasks are used to allow native execution of doTransaction to wait while
// Snapshot is
// processed by logic on the Dart side.
final TaskCompletionSource<Map<String, Object>> updateMutableDataTCS =
new TaskCompletionSource<>();
Expand Down Expand Up @@ -514,24 +541,25 @@ public void run() {
{
String eventType = call.argument("eventType");
int handle = nextHandle++;
Query query = getQuery(database, arguments);
MethodCallHandlerImpl.EventObserver observer =
new MethodCallHandlerImpl.EventObserver(eventType, handle);
new MethodCallHandlerImpl.EventObserver(channel, eventType, query, handle);
observers.put(handle, observer);
if (EVENT_TYPE_VALUE.equals(eventType)) {
getQuery(database, arguments).addValueEventListener(observer);
query.addValueEventListener(observer);
} else {
getQuery(database, arguments).addChildEventListener(observer);
query.addChildEventListener(observer);
}
result.success(handle);
break;
}

case "Query#removeObserver":
{
Query query = getQuery(database, arguments);
Integer handle = call.argument("handle");
MethodCallHandlerImpl.EventObserver observer = observers.get(handle);
if (observer != null) {
final Query query = observer.query;
if (observer.requestedEventType.equals(EVENT_TYPE_VALUE)) {
query.removeEventListener((ValueEventListener) observer);
} else {
Expand Down