Enforce all the SliceBackgroundWorkers being singletons at syntax level

- Create workers via reflection in SliceBackgroundWorker
- Store the workers in a static container and release then at shutdown()

Fixes: 118228009
Test: robolectric
Change-Id: I564277d3a12b2d7d3b50cef091bdfedb3397c145

src/com/android/settings/slices/SettingsSliceProvider.java

@@ -52,7 +52,6 @@ import com.android.settings.wifi.calling.WifiCallingSliceHelper;
 import com.android.settingslib.SliceBroadcastRelay;
 import com.android.settingslib.utils.ThreadUtils;
 
-import java.io.IOException;
 import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -134,8 +133,7 @@ public class SettingsSliceProvider extends SliceProvider {
 
     final Set<Uri> mRegisteredUris = new ArraySet<>();
 
-    final Map<Uri, SliceBackgroundWorker> mWorkerMap = new ArrayMap<>();
-    final Set<SliceBackgroundWorker> mLiveWorkers = new ArraySet<>();
+    final Map<Uri, SliceBackgroundWorker> mPinnedWorkers = new ArrayMap<>();
 
     public SettingsSliceProvider() {
         super(READ_SEARCH_INDEXABLES);
@@ -365,45 +363,37 @@ public class SettingsSliceProvider extends SliceProvider {
     }
 
     private void startBackgroundWorker(CustomSliceable sliceable) {
-        final SliceBackgroundWorker worker = sliceable.getBackgroundWorker();
-        if (worker == null) {
+        final Class workerClass = sliceable.getBackgroundWorkerClass();
+        if (workerClass == null) {
             return;
         }
 
         final Uri uri = sliceable.getUri();
-        if (mWorkerMap.containsKey(uri)) {
+        if (mPinnedWorkers.containsKey(uri)) {
             return;
         }
 
         Log.d(TAG, "Starting background worker for: " + uri);
-        mWorkerMap.put(uri, worker);
-        if (!mLiveWorkers.contains(worker)) {
-            mLiveWorkers.add(worker);
-        }
+        final SliceBackgroundWorker worker = SliceBackgroundWorker.getInstance(
+                getContext(), sliceable);
+        mPinnedWorkers.put(uri, worker);
         worker.onSlicePinned();
     }
 
     private void stopBackgroundWorker(Uri uri) {
-        final SliceBackgroundWorker worker = mWorkerMap.get(uri);
+        final SliceBackgroundWorker worker = mPinnedWorkers.get(uri);
         if (worker != null) {
             Log.d(TAG, "Stopping background worker for: " + uri);
             worker.onSliceUnpinned();
-            mWorkerMap.remove(uri);
+            mPinnedWorkers.remove(uri);
         }
     }
 
     @Override
     public void shutdown() {
-        for (SliceBackgroundWorker worker : mLiveWorkers) {
-            ThreadUtils.postOnMainThread(() -> {
-                try {
-                    worker.close();
-                } catch (IOException e) {
-                    Log.w(TAG, "Exception when shutting down worker", e);
-                }
-            });
-        }
-        mLiveWorkers.clear();
+        ThreadUtils.postOnMainThread(() -> {
+            SliceBackgroundWorker.shutdown();
+        });
     }
 
     private List<Uri> buildUrisFromKeys(List<String> keys, String authority) {
@@ -532,4 +522,4 @@ public class SettingsSliceProvider extends SliceProvider {
         }
         return new String[0];
     }
-}
+}