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Commit c8de8c70 authored by Willie Koomson's avatar Willie Koomson
Browse files

Rate limit calls to setWidgetPreview/removeWidgetPreview 

Rate limit calls to widget preview APIs that trigger the
onProvidersChanged callback. The rate limit does not apply if the caller
is currently in the foreground.

Bug: 308041327
Test: AppWidgetTest#testGeneratedPreviewRateLimiting
Change-Id: I6baaf5a1a94ad63584135b4f297eda9dd2e9cddc
parent a820b6f8

core/api/current.txt

+1 −1
Original line number Diff line number Diff line
@@ -9610,7 +9610,7 @@ package android.appwidget { 
    method public void partiallyUpdateAppWidget(int, android.widget.RemoteViews);

    method @FlaggedApi("android.appwidget.flags.generated_previews") public void removeWidgetPreview(@NonNull android.content.ComponentName, int);

    method public boolean requestPinAppWidget(@NonNull android.content.ComponentName, @Nullable android.os.Bundle, @Nullable android.app.PendingIntent);

    method @FlaggedApi("android.appwidget.flags.generated_previews") public void setWidgetPreview(@NonNull android.content.ComponentName, int, @NonNull android.widget.RemoteViews);

    method @FlaggedApi("android.appwidget.flags.generated_previews") public boolean setWidgetPreview(@NonNull android.content.ComponentName, int, @NonNull android.widget.RemoteViews);

    method public void updateAppWidget(int[], android.widget.RemoteViews);

    method public void updateAppWidget(int, android.widget.RemoteViews);

    method public void updateAppWidget(android.content.ComponentName, android.widget.RemoteViews);

core/java/android/appwidget/AppWidgetManager.java

+4 −2
Original line number Diff line number Diff line
@@ -1417,13 +1417,15 @@ public class AppWidgetManager { 
     * @see AppWidgetProviderInfo#WIDGET_CATEGORY_HOME_SCREEN

     * @see AppWidgetProviderInfo#WIDGET_CATEGORY_KEYGUARD

     * @see AppWidgetProviderInfo#WIDGET_CATEGORY_SEARCHBOX

     *

     * @return true if the call was successful, false if it was rate-limited.

     */

    @FlaggedApi(Flags.FLAG_GENERATED_PREVIEWS)

    public void setWidgetPreview(@NonNull ComponentName provider,

    public boolean setWidgetPreview(@NonNull ComponentName provider,

            @AppWidgetProviderInfo.CategoryFlags int widgetCategories,

            @NonNull RemoteViews preview) {

        try {

            mService.setWidgetPreview(provider, widgetCategories, preview);

            return mService.setWidgetPreview(provider, widgetCategories, preview);

        } catch (RemoteException e) {

            throw e.rethrowFromSystemServer();

        }

core/java/com/android/internal/appwidget/IAppWidgetService.aidl

+1 −2
Original line number Diff line number Diff line
@@ -80,11 +80,10 @@ interface IAppWidgetService { 
            in Bundle extras, in IntentSender resultIntent);

    boolean isRequestPinAppWidgetSupported();

    oneway void noteAppWidgetTapped(in String callingPackage, in int appWidgetId);

    void setWidgetPreview(in ComponentName providerComponent, in int widgetCategories,

    boolean setWidgetPreview(in ComponentName providerComponent, in int widgetCategories,

            in RemoteViews preview);

    @nullable RemoteViews getWidgetPreview(in String callingPackage,

            in ComponentName providerComponent, in int profileId, in int widgetCategory);

    void removeWidgetPreview(in ComponentName providerComponent, in int widgetCategories);



}

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

+13 −0
Original line number Diff line number Diff line
@@ -560,6 +560,19 @@ public final class SystemUiDeviceConfigFlags { 
     */

    public static final String CURSOR_HOVER_STATES_ENABLED = "cursor_hover_states_enabled";





    /*

     * (long) The reset interval for generated preview API calls.

     */

    public static final String GENERATED_PREVIEW_API_RESET_INTERVAL_MS =

            "generated_preview_api_reset_interval_ms";



    /*

     * (int) The max number of generated preview API calls per reset interval.

     */

    public static final String GENERATED_PREVIEW_API_MAX_CALLS_PER_INTERVAL =

            "generated_preview_api_max_calls_per_interval";



    private SystemUiDeviceConfigFlags() {

    }

}

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

+144 −5
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ import android.os.Binder; 
import android.os.Bundle;

import android.os.Environment;

import android.os.Handler;

import android.os.HandlerExecutor;

import android.os.IBinder;

import android.os.Looper;

import android.os.Message;
@@ -98,6 +99,7 @@ import android.provider.DeviceConfig; 
import android.service.appwidget.AppWidgetServiceDumpProto;

import android.service.appwidget.WidgetProto;

import android.text.TextUtils;

import android.util.ArrayMap;

import android.util.ArraySet;

import android.util.AtomicFile;

import android.util.AttributeSet;
@@ -148,6 +150,7 @@ import java.io.IOException; 
import java.io.OutputStream;

import java.io.PrintWriter;

import java.nio.charset.StandardCharsets;

import java.time.Duration;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;
@@ -159,6 +162,7 @@ import java.util.Map; 
import java.util.Objects;

import java.util.Set;

import java.util.concurrent.atomic.AtomicLong;

import java.util.function.LongSupplier;



class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBackupProvider,

        OnCrossProfileWidgetProvidersChangeListener {
@@ -187,6 +191,13 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
    // used to verify which request has successfully been received by the host.

    private static final AtomicLong UPDATE_COUNTER = new AtomicLong();



    // Default reset interval for generated preview API rate limiting.

    private static final long DEFAULT_GENERATED_PREVIEW_RESET_INTERVAL_MS =

            Duration.ofHours(1).toMillis();

    // Default max API calls per reset interval for generated preview API rate limiting.

    private static final int DEFAULT_GENERATED_PREVIEW_MAX_CALLS_PER_INTERVAL = 2;





    private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {

        @Override

        public void onReceive(Context context, Intent intent) {
@@ -266,6 +277,8 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
    // Mark widget lifecycle broadcasts as 'interactive'

    private Bundle mInteractiveBroadcast;



    private ApiCounter mGeneratedPreviewsApiCounter;



    AppWidgetServiceImpl(Context context) {

        mContext = context;

    }
@@ -294,6 +307,17 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
        mIsCombinedBroadcastEnabled = DeviceConfig.getBoolean(NAMESPACE_SYSTEMUI,

            SystemUiDeviceConfigFlags.COMBINED_BROADCAST_ENABLED, true);



        final long generatedPreviewResetInterval = DeviceConfig.getLong(NAMESPACE_SYSTEMUI,

                SystemUiDeviceConfigFlags.GENERATED_PREVIEW_API_RESET_INTERVAL_MS,

                DEFAULT_GENERATED_PREVIEW_RESET_INTERVAL_MS);

        final int generatedPreviewMaxCallsPerInterval = DeviceConfig.getInt(NAMESPACE_SYSTEMUI,

                SystemUiDeviceConfigFlags.GENERATED_PREVIEW_API_RESET_INTERVAL_MS,

                DEFAULT_GENERATED_PREVIEW_MAX_CALLS_PER_INTERVAL);

        mGeneratedPreviewsApiCounter = new ApiCounter(generatedPreviewResetInterval,

                generatedPreviewMaxCallsPerInterval);

        DeviceConfig.addOnPropertiesChangedListener(NAMESPACE_SYSTEMUI,

                new HandlerExecutor(mCallbackHandler), this::handleSystemUiDeviceConfigChange);



        BroadcastOptions opts = BroadcastOptions.makeBasic();

        opts.setBackgroundActivityStartsAllowed(false);

        opts.setInteractive(true);
@@ -2469,6 +2493,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
    private void deleteProviderLocked(Provider provider) {

        deleteWidgetsLocked(provider, UserHandle.USER_ALL);

        mProviders.remove(provider);

        mGeneratedPreviewsApiCounter.remove(provider.id);



        // no need to send the DISABLE broadcast, since the receiver is gone anyway

        cancelBroadcastsLocked(provider);
@@ -3993,7 +4018,7 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
    }



    @Override

    public void setWidgetPreview(@NonNull ComponentName providerComponent,

    public boolean setWidgetPreview(@NonNull ComponentName providerComponent,

            @AppWidgetProviderInfo.CategoryFlags int widgetCategories,

            @NonNull RemoteViews preview) {

        final int userId = UserHandle.getCallingUserId();
@@ -4015,8 +4040,12 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
                throw new IllegalArgumentException(

                        providerComponent + " is not a valid AppWidget provider");

            }

            if (mGeneratedPreviewsApiCounter.tryApiCall(providerId)) {

                provider.setGeneratedPreviewLocked(widgetCategories, preview);

                scheduleNotifyGroupHostsForProvidersChangedLocked(userId);

                return true;

            }

            return false;

        }

    }
@@ -4057,6 +4086,26 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
        }

    }



    private void handleSystemUiDeviceConfigChange(DeviceConfig.Properties properties) {

        Set<String> changed = properties.getKeyset();

        synchronized (mLock) {

            if (changed.contains(

                    SystemUiDeviceConfigFlags.GENERATED_PREVIEW_API_RESET_INTERVAL_MS)) {

                long resetIntervalMs = properties.getLong(

                        SystemUiDeviceConfigFlags.GENERATED_PREVIEW_API_RESET_INTERVAL_MS,

                        /* defaultValue= */ mGeneratedPreviewsApiCounter.getResetIntervalMs());

                mGeneratedPreviewsApiCounter.setResetIntervalMs(resetIntervalMs);

            }

            if (changed.contains(

                    SystemUiDeviceConfigFlags.GENERATED_PREVIEW_API_MAX_CALLS_PER_INTERVAL)) {

                int maxCallsPerInterval = properties.getInt(

                        SystemUiDeviceConfigFlags.GENERATED_PREVIEW_API_MAX_CALLS_PER_INTERVAL,

                        /* defaultValue= */ mGeneratedPreviewsApiCounter.getMaxCallsPerInterval());

                mGeneratedPreviewsApiCounter.setMaxCallsPerInterval(maxCallsPerInterval);

            }

        }

    }



    private final class CallbackHandler extends Handler {

        public static final int MSG_NOTIFY_UPDATE_APP_WIDGET = 1;

        public static final int MSG_NOTIFY_PROVIDER_CHANGED = 2;
@@ -4530,11 +4579,11 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
        }

    }



    private static final class ProviderId {

    static final class ProviderId {

        final int uid;

        final ComponentName componentName;



        private ProviderId(int uid, ComponentName componentName) {

        ProviderId(int uid, ComponentName componentName) {

            this.uid = uid;

            this.componentName = componentName;

        }
@@ -4777,6 +4826,96 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku 
        }

    }



    /**

     * This class keeps track of API calls and implements rate limiting. One instance of this class

     * tracks calls from all providers for one API, or a group of APIs that should share the same

     * rate limit.

     */

    static final class ApiCounter {



        private static final class ApiCallRecord {

            // Number of times the API has been called for this provider.

            public int apiCallCount = 0;

            // The last time (from SystemClock.elapsedRealtime) the api call count was reset.

            public long lastResetTimeMs = 0;



            void reset(long nowMs) {

                apiCallCount = 0;

                lastResetTimeMs = nowMs;

            }

        }



        private final Map<ProviderId, ApiCallRecord> mCallCount = new ArrayMap<>();

        // The interval at which the call count is reset.

        private long mResetIntervalMs;

        // The max number of API calls per interval.

        private int mMaxCallsPerInterval;

        // Returns the current time (monotonic). By default this is SystemClock.elapsedRealtime.

        private LongSupplier mMonotonicClock;



        ApiCounter(long resetIntervalMs, int maxCallsPerInterval) {

            this(resetIntervalMs, maxCallsPerInterval, SystemClock::elapsedRealtime);

        }



        ApiCounter(long resetIntervalMs, int maxCallsPerInterval,

                LongSupplier monotonicClock) {

            mResetIntervalMs = resetIntervalMs;

            mMaxCallsPerInterval = maxCallsPerInterval;

            mMonotonicClock = monotonicClock;

        }



        public void setResetIntervalMs(long resetIntervalMs) {

            mResetIntervalMs = resetIntervalMs;

        }



        public long getResetIntervalMs() {

            return mResetIntervalMs;

        }



        public void setMaxCallsPerInterval(int maxCallsPerInterval) {

            mMaxCallsPerInterval = maxCallsPerInterval;

        }



        public int getMaxCallsPerInterval() {

            return mMaxCallsPerInterval;

        }



        /**

         * Returns true if the API call for the provider should be allowed, false if it should be

         * rate-limited.

         */

        public boolean tryApiCall(@NonNull ProviderId provider) {

            final ApiCallRecord record = getOrCreateRecord(provider);

            final long now = mMonotonicClock.getAsLong();

            final long timeSinceLastResetMs = now - record.lastResetTimeMs;

            // If the last reset was beyond the reset interval, reset now.

            if (timeSinceLastResetMs > mResetIntervalMs) {

                record.reset(now);

            }

            if (record.apiCallCount < mMaxCallsPerInterval) {

                record.apiCallCount++;

                return true;

            }

            return false;

        }



        /**

         * Remove the provider's call record from this counter, when the provider is no longer

         * tracked.

         */

        public void remove(@NonNull ProviderId id) {

            mCallCount.remove(id);

        }



        @NonNull

        private ApiCallRecord getOrCreateRecord(@NonNull ProviderId provider) {

            if (!mCallCount.containsKey(provider)) {

                mCallCount.put(provider, new ApiCallRecord());

            }

            return mCallCount.get(provider);

        }

    }



    private class LoadedWidgetState {

        final Widget widget;

        final int hostTag;