CommunalSourcePackageObserver Introduction.

This changelist introduces the CommunalSourcePackageObserver,
which handles notifying when the package is updated or
added.

Bug: 202784947
Test: atest CommunalSourcePackageObserverTest
Change-Id: I945717af0dec15532bdd0a110d5f92859bbdf118

packages/SystemUI/src/com/android/systemui/communal/PackageObserver.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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 com.android.systemui.communal;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.PatternMatcher;
+import android.util.Log;
+
+import com.google.android.collect.Lists;
+
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.Iterator;
+
+/**
+ * {@link PackageObserver} allows for monitoring the system for changes relating to a particular
+ * package. This can be used by {@link CommunalSource} clients to detect when a related package
+ * has changed and reloading is necessary.
+ */
+public class PackageObserver implements CommunalSource.Observer {
+    private static final String TAG = "PackageObserver";
+    private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
+
+    private final ArrayList<WeakReference<Callback>> mCallbacks = Lists.newArrayList();
+
+    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if (DEBUG) {
+                Log.d(TAG, "package added receiver - onReceive");
+            }
+
+            final Iterator<WeakReference<Callback>> iter = mCallbacks.iterator();
+            while (iter.hasNext()) {
+                final Callback callback = iter.next().get();
+                if (callback != null) {
+                    callback.onSourceChanged();
+                } else {
+                    iter.remove();
+                }
+            }
+        }
+    };
+
+    private final String mPackageName;
+    private final Context mContext;
+
+    public PackageObserver(Context context, String packageName) {
+        mContext = context;
+        mPackageName = packageName;
+    }
+
+    @Override
+    public void addCallback(Callback callback) {
+        if (DEBUG) {
+            Log.d(TAG, "addCallback:" + callback);
+        }
+        mCallbacks.add(new WeakReference<>(callback));
+
+        // Only register for listening to package additions on first callback.
+        if (mCallbacks.size() > 1) {
+            return;
+        }
+
+        final IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
+        filter.addDataScheme("package");
+        filter.addDataSchemeSpecificPart(mPackageName, PatternMatcher.PATTERN_LITERAL);
+        // Note that we directly register the receiver here as data schemes are not supported by
+        // BroadcastDispatcher.
+        mContext.registerReceiver(mReceiver, filter, Context.RECEIVER_EXPORTED);
+    }
+
+    @Override
+    public void removeCallback(Callback callback) {
+        if (DEBUG) {
+            Log.d(TAG, "removeCallback:" + callback);
+        }
+        final boolean removed = mCallbacks.removeIf(el -> el.get() == callback);
+
+        if (removed && mCallbacks.isEmpty()) {
+            mContext.unregisterReceiver(mReceiver);
+        }
+    }
+}

packages/SystemUI/src/com/android/systemui/communal/dagger/CommunalModule.java

@@ -16,18 +16,26 @@
 
 package com.android.systemui.communal.dagger;
 
+import android.content.ComponentName;
 import android.content.Context;
+import android.content.res.Resources;
+import android.text.TextUtils;
 import android.view.View;
 import android.widget.FrameLayout;
 
+import com.android.systemui.R;
+import com.android.systemui.communal.CommunalSource;
+import com.android.systemui.communal.PackageObserver;
 import com.android.systemui.communal.conditions.CommunalCondition;
 import com.android.systemui.communal.conditions.CommunalSettingCondition;
+import com.android.systemui.dagger.qualifiers.Main;
 import com.android.systemui.idle.AmbientLightModeMonitor;
 import com.android.systemui.idle.LightSensorEventsDebounceAlgorithm;
 import com.android.systemui.idle.dagger.IdleViewComponent;
 
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.Optional;
 import java.util.Set;
 
 import javax.inject.Named;
@@ -56,6 +64,20 @@ public interface CommunalModule {
         return view;
     }
 
+    /** */
+    @Provides
+    static Optional<CommunalSource.Observer> provideCommunalSourcePackageObserver(
+            Context context, @Main Resources resources) {
+        final String componentName = resources.getString(R.string.config_communalSourceComponent);
+
+        if (TextUtils.isEmpty(componentName)) {
+            return Optional.empty();
+        }
+
+        return Optional.of(new PackageObserver(context,
+                ComponentName.unflattenFromString(componentName).getPackageName()));
+    }
+
     /**
      * Provides LightSensorEventsDebounceAlgorithm as an instance to DebounceAlgorithm interface.
      * @param algorithm the instance of algorithm that is bound to the interface.

packages/SystemUI/tests/src/com/android/systemui/communal/PackageObserverTest.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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 com.android.systemui.communal;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.verify;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.testing.AndroidTestingRunner;
+
+import androidx.test.filters.SmallTest;
+
+import com.android.systemui.SysuiTestCase;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+@SmallTest
+@RunWith(AndroidTestingRunner.class)
+public class PackageObserverTest extends SysuiTestCase {
+    private static final String PACKAGE_NAME = "com.foo.bar";
+
+    @Mock
+    Context mContext;
+
+    @Mock
+    CommunalSource.Observer.Callback mCallback;
+
+    @Before
+    public void setup() {
+        MockitoAnnotations.initMocks(this);
+    }
+
+    @Test
+    public void testChange() {
+        final PackageObserver observer = new PackageObserver(mContext, PACKAGE_NAME);
+        final ArgumentCaptor<BroadcastReceiver> receiverCapture =
+                ArgumentCaptor.forClass(BroadcastReceiver.class);
+
+        observer.addCallback(mCallback);
+
+        // Verify broadcast receiver registered.
+        verify(mContext).registerReceiver(receiverCapture.capture(), any(), anyInt());
+
+        // Simulate package change.
+        receiverCapture.getValue().onReceive(mContext, new Intent());
+
+        // Check that callback was informed.
+        verify(mCallback).onSourceChanged();
+
+        observer.removeCallback(mCallback);
+
+        // Make sure receiver is unregistered on last callback removal
+        verify(mContext).unregisterReceiver(receiverCapture.getValue());
+    }
+}