Add in-memory storage for listeners used by RecoverableKeyStoreLoader

/*

 * Copyright (C) 2017 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.locksettings.recoverablekeystore;

import android.annotation.Nullable;

import android.app.PendingIntent;

import com.android.internal.annotations.VisibleForTesting;

import java.util.Map;

import java.util.HashMap;

/**

 * In memory storage for listeners to be notified when new recovery snapshot is available.

 * Note: implementation is not thread safe and it is used to mock final {@link PendingIntent}

 * class.

 *

 * @hide

 */

public class ListenersStorage {

    private Map<Integer, PendingIntent> mAgentIntents = new HashMap<>();

    private static final ListenersStorage mInstance = new ListenersStorage();

    public static ListenersStorage getInstance() {

        return mInstance;

    }

    /**

     * Sets new listener for the recovery agent, identified by {@code uid}

     *

     * @param recoveryAgentUid uid

     * @param intent PendingIntent which will be triggered than new snapshot is available.

     */

    public void setSnapshotListener(int recoveryAgentUid, @Nullable PendingIntent intent) {

        mAgentIntents.put(recoveryAgentUid, intent);

    }

    /**

     * Notifies recovery agent, that new snapshot is available.

     * Does nothing if a listener was not registered.

     *

     * @param recoveryAgentUid uid.

     */

    public void recoverySnapshotAvailable(int recoveryAgentUid) {

        PendingIntent intent = mAgentIntents.get(recoveryAgentUid);

        if (intent != null) {

            try {

                intent.send();

            } catch (PendingIntent.CanceledException e) {

                // Ignore - sending intent is not allowed.

            }

        }

    }

}