Merge "Implement extra persistence layer for widget provider info" into tm-dev

core/java/com/android/internal/config/sysui/SystemUiDeviceConfigFlags.java

@@ -536,6 +536,12 @@ public final class SystemUiDeviceConfigFlags {
      */
     public static final String CLIPBOARD_OVERLAY_ENABLED = "clipboard_overlay_enabled";
 
+    /**
+     * (boolean) Whether widget provider info would be saved to / loaded from system persistence
+     * layer as opposed to individual manifests in respective apps.
+     */
+    public static final String PERSISTS_WIDGET_PROVIDER_INFO = "persists_widget_provider_info";
+
     private SystemUiDeviceConfigFlags() {
     }
 }

services/appwidget/java/com/android/server/appwidget/AppWidgetServiceImpl.java

@@ -20,9 +20,11 @@ import static android.content.Context.KEYGUARD_SERVICE;
 import static android.content.Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS;
 import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 import static android.content.res.Resources.ID_NULL;
+import static android.provider.DeviceConfig.NAMESPACE_SYSTEMUI;
 
 import static com.android.server.pm.PackageManagerService.PLATFORM_PACKAGE_NAME;
 
+import android.annotation.NonNull;
 import android.annotation.UserIdInt;
 import android.app.ActivityManager;
 import android.app.ActivityManagerInternal;
@@ -83,6 +85,7 @@ import android.os.SystemClock;
 import android.os.Trace;
 import android.os.UserHandle;
 import android.os.UserManager;
+import android.provider.DeviceConfig;
 import android.service.appwidget.AppWidgetServiceDumpProto;
 import android.service.appwidget.WidgetProto;
 import android.text.TextUtils;
@@ -113,6 +116,7 @@ import com.android.internal.app.SuspendedAppActivity;
 import com.android.internal.app.UnlaunchableAppActivity;
 import com.android.internal.appwidget.IAppWidgetHost;
 import com.android.internal.appwidget.IAppWidgetService;
+import com.android.internal.config.sysui.SystemUiDeviceConfigFlags;
 import com.android.internal.os.BackgroundThread;
 import com.android.internal.os.SomeArgs;
 import com.android.internal.util.ArrayUtils;
@@ -150,6 +154,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
     private static final String TAG = "AppWidgetServiceImpl";
 
     private static final boolean DEBUG = false;
+    private static final boolean DEBUG_PROVIDER_INFO_CACHE = true;
 
     private static final String OLD_KEYGUARD_HOST_PACKAGE = "android";
     private static final String NEW_KEYGUARD_HOST_PACKAGE = "com.android.keyguard";
@@ -246,6 +251,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
 
     private boolean mSafeMode;
     private int mMaxWidgetBitmapMemory;
+    private boolean mIsProviderInfoPersisted;
 
     AppWidgetServiceImpl(Context context) {
         mContext = context;
@@ -263,6 +269,12 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         mCallbackHandler = new CallbackHandler(mContext.getMainLooper());
         mBackupRestoreController = new BackupRestoreController();
         mSecurityPolicy = new SecurityPolicy();
+        mIsProviderInfoPersisted = !ActivityManager.isLowRamDeviceStatic()
+                && DeviceConfig.getBoolean(NAMESPACE_SYSTEMUI,
+                SystemUiDeviceConfigFlags.PERSISTS_WIDGET_PROVIDER_INFO, true);
+        if (DEBUG_PROVIDER_INFO_CACHE && !mIsProviderInfoPersisted) {
+            Slog.d(TAG, "App widget provider info will not be persisted on this device");
+        }
 
         computeMaximumWidgetBitmapMemory();
         registerBroadcastReceiver();
@@ -607,10 +619,12 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         }
     }
 
+    @GuardedBy("mLock")
     private void ensureGroupStateLoadedLocked(int userId) {
         ensureGroupStateLoadedLocked(userId, /* enforceUserUnlockingOrUnlocked */ true );
     }
 
+    @GuardedBy("mLock")
     private void ensureGroupStateLoadedLocked(int userId, boolean enforceUserUnlockingOrUnlocked) {
         if (enforceUserUnlockingOrUnlocked && !isUserRunningAndUnlocked(userId)) {
             throw new IllegalStateException(
@@ -2184,6 +2198,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         }
     }
 
+    @GuardedBy("mLock")
     private void loadGroupWidgetProvidersLocked(int[] profileIds) {
         List<ResolveInfo> allReceivers = null;
         Intent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
@@ -2409,7 +2424,24 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         }
     }
 
-    private static void serializeProvider(TypedXmlSerializer out, Provider p) throws IOException {
+    private static void serializeProvider(
+            @NonNull final TypedXmlSerializer out, @NonNull final Provider p) throws IOException {
+        Objects.requireNonNull(out);
+        Objects.requireNonNull(p);
+        serializeProviderInner(out, p, false /* persistsProviderInfo */);
+    }
+
+    private static void serializeProviderWithProviderInfo(
+            @NonNull final TypedXmlSerializer out, @NonNull final Provider p) throws IOException {
+        Objects.requireNonNull(out);
+        Objects.requireNonNull(p);
+        serializeProviderInner(out, p, true /* persistsProviderInfo */);
+    }
+
+    private static void serializeProviderInner(@NonNull final TypedXmlSerializer out,
+            @NonNull final Provider p, final boolean persistsProviderInfo) throws IOException {
+        Objects.requireNonNull(out);
+        Objects.requireNonNull(p);
         out.startTag(null, "p");
         out.attribute(null, "pkg", p.id.componentName.getPackageName());
         out.attribute(null, "cl", p.id.componentName.getClassName());
@@ -2417,6 +2449,12 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         if (!TextUtils.isEmpty(p.infoTag)) {
             out.attribute(null, "info_tag", p.infoTag);
         }
+        if (DEBUG_PROVIDER_INFO_CACHE && persistsProviderInfo && !p.mInfoParsed) {
+            Slog.d(TAG, "Provider info from " + p.id.componentName + " won't be persisted.");
+        }
+        if (persistsProviderInfo && p.mInfoParsed) {
+            AppWidgetXmlUtil.writeAppWidgetProviderInfoLocked(out, p.info);
+        }
         out.endTag(null, "p");
     }
 
@@ -2768,6 +2806,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
     }
 
     // only call from initialization -- it assumes that the data structures are all empty
+    @GuardedBy("mLock")
     private void loadGroupStateLocked(int[] profileIds) {
         // We can bind the widgets to host and providers only after
         // reading the host and providers for all users since a widget
@@ -2959,6 +2998,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         return false;
     }
 
+    @GuardedBy("mLock")
     private void saveStateLocked(int userId) {
         tagProvidersAndHosts();
 
@@ -3012,6 +3052,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         }
     }
 
+    @GuardedBy("mLock")
     private boolean writeProfileStateToFileLocked(FileOutputStream stream, int userId) {
         int N;
 
@@ -3028,7 +3069,9 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
                 if (provider.getUserId() != userId) {
                     continue;
                 }
-                if (provider.shouldBePersisted()) {
+                if (mIsProviderInfoPersisted) {
+                    serializeProviderWithProviderInfo(out, provider);
+                } else if (provider.shouldBePersisted()) {
                     serializeProvider(out, provider);
                 }
             }
@@ -3074,6 +3117,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         }
     }
 
+    @GuardedBy("mLock")
     private int readProfileStateFromFileLocked(FileInputStream stream, int userId,
             List<LoadedWidgetState> outLoadedWidgets) {
         int version = -1;
@@ -3127,6 +3171,18 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
                             provider.zombie = true;
                             provider.id = providerId;
                             mProviders.add(provider);
+                        } else if (mIsProviderInfoPersisted) {
+                            final AppWidgetProviderInfo info =
+                                    AppWidgetXmlUtil.readAppWidgetProviderInfoLocked(parser);
+                            if (DEBUG_PROVIDER_INFO_CACHE && info == null) {
+                                Slog.d(TAG, "Unable to load widget provider info from xml for "
+                                        + providerId.componentName);
+                            }
+                            if (info != null) {
+                                info.provider = providerId.componentName;
+                                info.providerInfo = providerInfo;
+                                provider.setInfoLocked(info);
+                            }
                         }
 
                         final int providerTag = parser.getAttributeIntHex(null, "tag",

services/appwidget/java/com/android/server/appwidget/AppWidgetXmlUtil.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2022 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.server.appwidget;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.appwidget.AppWidgetProviderInfo;
+import android.content.ComponentName;
+import android.os.Build;
+import android.text.TextUtils;
+import android.util.TypedXmlPullParser;
+import android.util.TypedXmlSerializer;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * @hide
+ */
+public class AppWidgetXmlUtil {
+
+    private static final String ATTR_MIN_WIDTH = "min_width";
+    private static final String ATTR_MIN_HEIGHT = "min_height";
+    private static final String ATTR_MIN_RESIZE_WIDTH = "min_resize_width";
+    private static final String ATTR_MIN_RESIZE_HEIGHT = "min_resize_height";
+    private static final String ATTR_MAX_RESIZE_WIDTH = "max_resize_width";
+    private static final String ATTR_MAX_RESIZE_HEIGHT = "max_resize_height";
+    private static final String ATTR_TARGET_CELL_WIDTH = "target_cell_width";
+    private static final String ATTR_TARGET_CELL_HEIGHT = "target_cell_height";
+    private static final String ATTR_UPDATE_PERIOD_MILLIS = "update_period_millis";
+    private static final String ATTR_INITIAL_LAYOUT = "initial_layout";
+    private static final String ATTR_INITIAL_KEYGUARD_LAYOUT = "initial_keyguard_layout";
+    private static final String ATTR_CONFIGURE = "configure";
+    private static final String ATTR_LABEL = "label";
+    private static final String ATTR_ICON = "icon";
+    private static final String ATTR_PREVIEW_IMAGE = "preview_image";
+    private static final String ATTR_PREVIEW_LAYOUT = "preview_layout";
+    private static final String ATTR_AUTO_ADVANCED_VIEW_ID = "auto_advance_view_id";
+    private static final String ATTR_RESIZE_MODE = "resize_mode";
+    private static final String ATTR_WIDGET_CATEGORY = "widget_category";
+    private static final String ATTR_WIDGET_FEATURES = "widget_features";
+    private static final String ATTR_DESCRIPTION_RES = "description_res";
+    private static final String ATTR_OS_FINGERPRINT = "os_fingerprint";
+
+    /**
+     * @hide
+     */
+    public static void writeAppWidgetProviderInfoLocked(@NonNull final TypedXmlSerializer out,
+            @NonNull final AppWidgetProviderInfo info) throws IOException {
+        Objects.requireNonNull(out);
+        Objects.requireNonNull(info);
+        out.attributeInt(null, ATTR_MIN_WIDTH, info.minWidth);
+        out.attributeInt(null, ATTR_MIN_HEIGHT, info.minHeight);
+        out.attributeInt(null, ATTR_MIN_RESIZE_WIDTH, info.minResizeWidth);
+        out.attributeInt(null, ATTR_MIN_RESIZE_HEIGHT, info.minResizeHeight);
+        out.attributeInt(null, ATTR_MAX_RESIZE_WIDTH, info.maxResizeWidth);
+        out.attributeInt(null, ATTR_MAX_RESIZE_HEIGHT, info.maxResizeHeight);
+        out.attributeInt(null, ATTR_TARGET_CELL_WIDTH, info.targetCellWidth);
+        out.attributeInt(null, ATTR_TARGET_CELL_HEIGHT, info.targetCellHeight);
+        out.attributeInt(null, ATTR_UPDATE_PERIOD_MILLIS, info.updatePeriodMillis);
+        out.attributeInt(null, ATTR_INITIAL_LAYOUT, info.initialLayout);
+        out.attributeInt(null, ATTR_INITIAL_KEYGUARD_LAYOUT, info.initialKeyguardLayout);
+        if (info.configure != null) {
+            out.attribute(null, ATTR_CONFIGURE, info.configure.flattenToShortString());
+        }
+        out.attribute(null, ATTR_LABEL, info.label);
+        out.attributeInt(null, ATTR_ICON, info.icon);
+        out.attributeInt(null, ATTR_PREVIEW_IMAGE, info.previewImage);
+        out.attributeInt(null, ATTR_PREVIEW_LAYOUT, info.previewLayout);
+        out.attributeInt(null, ATTR_AUTO_ADVANCED_VIEW_ID, info.autoAdvanceViewId);
+        out.attributeInt(null, ATTR_RESIZE_MODE, info.resizeMode);
+        out.attributeInt(null, ATTR_WIDGET_CATEGORY, info.widgetCategory);
+        out.attributeInt(null, ATTR_WIDGET_FEATURES, info.widgetFeatures);
+        out.attributeInt(null, ATTR_DESCRIPTION_RES, info.descriptionRes);
+        out.attribute(null, ATTR_OS_FINGERPRINT, Build.FINGERPRINT);
+    }
+
+    /**
+     * @hide
+     */
+    @Nullable
+    public static AppWidgetProviderInfo readAppWidgetProviderInfoLocked(
+            @NonNull final TypedXmlPullParser parser) {
+        Objects.requireNonNull(parser);
+        final String fingerprint = parser.getAttributeValue(null, ATTR_OS_FINGERPRINT);
+        if (!Build.FINGERPRINT.equals(fingerprint)) {
+            return null;
+        }
+        final AppWidgetProviderInfo info = new AppWidgetProviderInfo();
+        info.minWidth = parser.getAttributeInt(null, ATTR_MIN_WIDTH, 0);
+        info.minHeight = parser.getAttributeInt(null, ATTR_MIN_HEIGHT, 0);
+        info.minResizeWidth = parser.getAttributeInt(null, ATTR_MIN_RESIZE_WIDTH, 0);
+        info.minResizeWidth = parser.getAttributeInt(null, ATTR_MIN_RESIZE_HEIGHT, 0);
+        info.maxResizeWidth = parser.getAttributeInt(null, ATTR_MAX_RESIZE_WIDTH, 0);
+        info.maxResizeHeight = parser.getAttributeInt(null, ATTR_MAX_RESIZE_HEIGHT, 0);
+        info.targetCellWidth = parser.getAttributeInt(null, ATTR_TARGET_CELL_WIDTH, 0);
+        info.targetCellHeight = parser.getAttributeInt(null, ATTR_TARGET_CELL_HEIGHT, 0);
+        info.updatePeriodMillis = parser.getAttributeInt(null, ATTR_UPDATE_PERIOD_MILLIS, 0);
+        info.initialLayout = parser.getAttributeInt(null, ATTR_INITIAL_LAYOUT, 0);
+        info.initialKeyguardLayout = parser.getAttributeInt(
+                null, ATTR_INITIAL_KEYGUARD_LAYOUT, 0);
+        final String configure = parser.getAttributeValue(null, ATTR_CONFIGURE);
+        if (!TextUtils.isEmpty(configure)) {
+            info.configure = ComponentName.unflattenFromString(configure);
+        }
+        info.label = parser.getAttributeValue(null, ATTR_LABEL);
+        info.icon = parser.getAttributeInt(null, ATTR_ICON, 0);
+        info.previewImage = parser.getAttributeInt(null, ATTR_PREVIEW_IMAGE, 0);
+        info.previewLayout = parser.getAttributeInt(null, ATTR_PREVIEW_LAYOUT, 0);
+        info.autoAdvanceViewId = parser.getAttributeInt(null, ATTR_AUTO_ADVANCED_VIEW_ID, 0);
+        info.resizeMode = parser.getAttributeInt(null, ATTR_RESIZE_MODE, 0);
+        info.widgetCategory = parser.getAttributeInt(null, ATTR_WIDGET_CATEGORY, 0);
+        info.widgetFeatures = parser.getAttributeInt(null, ATTR_WIDGET_FEATURES, 0);
+        info.descriptionRes = parser.getAttributeInt(null, ATTR_DESCRIPTION_RES, 0);
+        return info;
+    }
+}

services/tests/servicestests/src/com/android/server/appwidget/AppWidgetServiceImplTest.java

@@ -28,6 +28,9 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.app.AppOpsManagerInternal;
 import android.app.admin.DevicePolicyManagerInternal;
 import android.appwidget.AppWidgetManager;
 import android.appwidget.AppWidgetManagerInternal;
@@ -39,11 +42,16 @@ import android.content.ContextWrapper;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.pm.LauncherApps;
+import android.content.pm.PackageManagerInternal;
 import android.content.pm.ShortcutServiceInternal;
 import android.os.Handler;
 import android.os.UserHandle;
 import android.test.InstrumentationTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
+import android.util.AtomicFile;
+import android.util.TypedXmlPullParser;
+import android.util.TypedXmlSerializer;
+import android.util.Xml;
 import android.widget.RemoteViews;
 
 import com.android.frameworks.servicestests.R;
@@ -51,9 +59,16 @@ import com.android.internal.appwidget.IAppWidgetHost;
 import com.android.server.LocalServices;
 
 import org.mockito.ArgumentCaptor;
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
 
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Objects;
 import java.util.Random;
 import java.util.concurrent.CountDownLatch;
 
@@ -77,6 +92,8 @@ public class AppWidgetServiceImplTest extends InstrumentationTestCase {
     private AppWidgetManager mManager;
 
     private ShortcutServiceInternal mMockShortcutService;
+    private PackageManagerInternal mMockPackageManager;
+    private AppOpsManagerInternal mMockAppOpsManagerInternal;
     private IAppWidgetHost mMockHost;
 
     @Override
@@ -85,6 +102,8 @@ public class AppWidgetServiceImplTest extends InstrumentationTestCase {
         LocalServices.removeServiceForTest(DevicePolicyManagerInternal.class);
         LocalServices.removeServiceForTest(ShortcutServiceInternal.class);
         LocalServices.removeServiceForTest(AppWidgetManagerInternal.class);
+        LocalServices.removeServiceForTest(PackageManagerInternal.class);
+        LocalServices.removeServiceForTest(AppOpsManagerInternal.class);
 
         mTestContext = new TestContext();
         mPkgName = mTestContext.getOpPackageName();
@@ -92,9 +111,16 @@ public class AppWidgetServiceImplTest extends InstrumentationTestCase {
         mManager = new AppWidgetManager(mTestContext, mService);
 
         mMockShortcutService = mock(ShortcutServiceInternal.class);
+        mMockPackageManager = mock(PackageManagerInternal.class);
+        mMockAppOpsManagerInternal = mock(AppOpsManagerInternal.class);
         mMockHost = mock(IAppWidgetHost.class);
         LocalServices.addService(ShortcutServiceInternal.class, mMockShortcutService);
+        LocalServices.addService(PackageManagerInternal.class, mMockPackageManager);
+        LocalServices.addService(AppOpsManagerInternal.class, mMockAppOpsManagerInternal);
+        when(mMockPackageManager.filterAppAccess(anyString(), anyInt(), anyInt()))
+                .thenReturn(false);
         mService.onStart();
+        mService.systemServicesReady();
     }
 
     public void testLoadDescription() {
@@ -323,6 +349,34 @@ public class AppWidgetServiceImplTest extends InstrumentationTestCase {
         assertThat(info.previewLayout).isEqualTo(R.layout.widget_preview);
     }
 
+    public void testWidgetProviderInfoPersistence() throws IOException {
+        final AppWidgetProviderInfo original = new AppWidgetProviderInfo();
+        original.minWidth = 40;
+        original.minHeight = 40;
+        original.maxResizeWidth = 250;
+        original.maxResizeHeight = 120;
+        original.targetCellWidth = 1;
+        original.targetCellHeight = 1;
+        original.updatePeriodMillis = 86400000;
+        original.previewLayout = R.layout.widget_preview;
+        original.label = "test";
+
+        final File file = new File(mTestContext.getDataDir(), "appwidget_provider_info.xml");
+        saveWidgetProviderInfoLocked(file, original);
+        final AppWidgetProviderInfo target = loadAppWidgetProviderInfoLocked(file);
+
+        assertThat(target.minWidth).isEqualTo(original.minWidth);
+        assertThat(target.minHeight).isEqualTo(original.minHeight);
+        assertThat(target.minResizeWidth).isEqualTo(original.minResizeWidth);
+        assertThat(target.minResizeHeight).isEqualTo(original.minResizeHeight);
+        assertThat(target.maxResizeWidth).isEqualTo(original.maxResizeWidth);
+        assertThat(target.maxResizeHeight).isEqualTo(original.maxResizeHeight);
+        assertThat(target.targetCellWidth).isEqualTo(original.targetCellWidth);
+        assertThat(target.targetCellHeight).isEqualTo(original.targetCellHeight);
+        assertThat(target.updatePeriodMillis).isEqualTo(original.updatePeriodMillis);
+        assertThat(target.previewLayout).isEqualTo(original.previewLayout);
+    }
+
     private int setupHostAndWidget() {
         List<PendingHostUpdate> updates = mService.startListening(
                 mMockHost, mPkgName, HOST_ID, new int[0]).getList();
@@ -353,6 +407,44 @@ public class AppWidgetServiceImplTest extends InstrumentationTestCase {
         return mTestContext.getResources().getInteger(resId);
     }
 
+    private static void saveWidgetProviderInfoLocked(@NonNull final File dst,
+            @Nullable final AppWidgetProviderInfo info)
+            throws IOException {
+        Objects.requireNonNull(dst);
+        if (info == null) {
+            return;
+        }
+        final AtomicFile file = new AtomicFile(dst);
+        final FileOutputStream stream = file.startWrite();
+        final TypedXmlSerializer out = Xml.resolveSerializer(stream);
+        out.startDocument(null, true);
+        out.startTag(null, "p");
+        AppWidgetXmlUtil.writeAppWidgetProviderInfoLocked(out, info);
+        out.endTag(null, "p");
+        out.endDocument();
+        file.finishWrite(stream);
+    }
+
+    public static AppWidgetProviderInfo loadAppWidgetProviderInfoLocked(@NonNull final File dst) {
+        Objects.requireNonNull(dst);
+        final AtomicFile file = new AtomicFile(dst);
+        try (FileInputStream stream = file.openRead()) {
+            final TypedXmlPullParser parser = Xml.resolvePullParser(stream);
+            int type;
+            while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
+                    && type != XmlPullParser.START_TAG) {
+                // drain whitespace, comments, etc.
+            }
+            final String nodeName = parser.getName();
+            if (!"p".equals(nodeName)) {
+                return null;
+            }
+            return AppWidgetXmlUtil.readAppWidgetProviderInfoLocked(parser);
+        } catch (IOException | XmlPullParserException e) {
+            return null;
+        }
+    }
+
     private class TestContext extends ContextWrapper {
 
         public TestContext() {