Use serial executor for permission operations.

/**

 * Calls from the system into the permission controller.

 *

 * All methods are called async beside the backup related method. For these we force to use the

 * async-task single thread executor so that multiple parallel backups don't override the delayed

 * the backup state racily.

 * All reading methods are called async, and all writing method are called on the AsyncTask single

 * thread executor so that multiple writes won't override each other concurrently.

 */

public final class PermissionControllerServiceImpl extends PermissionControllerService {

    private static final String LOG_TAG = PermissionControllerServiceImpl.class.getSimpleName();

    public void onRevokeRuntimePermissions(@NonNull Map<String, List<String>> request,

            boolean doDryRun, int reason, @NonNull String callerPackageName,

            @NonNull Consumer<Map<String, List<String>>> callback) {

        AsyncTask.THREAD_POOL_EXECUTOR.execute(() -> callback.accept(

                onRevokeRuntimePermissions(request, doDryRun, reason, callerPackageName)));

        AsyncTask.execute(() -> callback.accept(onRevokeRuntimePermissions(request, doDryRun,

                reason, callerPackageName)));

    }

    private @NonNull Map<String, List<String>> onRevokeRuntimePermissions(

    @Override

    public void onRevokeRuntimePermission(@NonNull String packageName,

            @NonNull String permissionName, @NonNull Runnable callback) {

        AsyncTask.THREAD_POOL_EXECUTOR.execute(() -> {

        AsyncTask.execute(() -> {

            onRevokeRuntimePermission(packageName, permissionName);

            callback.run();

        });

    public void onSetRuntimePermissionGrantStateByDeviceAdmin(@NonNull String callerPackageName,

            @NonNull String packageName, @NonNull String unexpandedPermission, int grantState,

            @NonNull Consumer<Boolean> callback) {

        AsyncTask.THREAD_POOL_EXECUTOR.execute(() -> callback.accept(

                onSetRuntimePermissionGrantStateByDeviceAdmin(callerPackageName, packageName,

                        unexpandedPermission, grantState)));

        AsyncTask.execute(() -> callback.accept(onSetRuntimePermissionGrantStateByDeviceAdmin(

                callerPackageName, packageName, unexpandedPermission, grantState)));

    }

    private boolean onSetRuntimePermissionGrantStateByDeviceAdmin(@NonNull String callerPackageName,

    @Override

    public void onGrantOrUpgradeDefaultRuntimePermissions(@NonNull Runnable callback) {

        AsyncTask.THREAD_POOL_EXECUTOR.execute(() -> {

        AsyncTask.execute(() -> {

            onGrantOrUpgradeDefaultRuntimePermissions();

            callback.run();

        });