1/*
2 * Copyright 2016, The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package com.android.managedprovisioning.common;
17
18import android.content.Context;
19import android.content.SharedPreferences;
20import android.support.annotation.VisibleForTesting;
21
22public class ManagedProvisioningSharedPreferences {
23    public static final long DEFAULT_PROVISIONING_ID = 0L;
24
25    @VisibleForTesting
26    static final String KEY_PROVISIONING_ID = "provisioning_id";
27
28    @VisibleForTesting
29    static final String SHARED_PREFERENCE = "managed_profile_shared_preferences";
30
31    /**
32     * It's a process-wise in-memory write lock. No other processes will write the same file.
33     */
34    private static final Object sWriteLock = new Object();
35
36    private final SharedPreferences mSharedPreferences;
37
38    public ManagedProvisioningSharedPreferences(Context context) {
39        mSharedPreferences = context.getSharedPreferences(SHARED_PREFERENCE, Context.MODE_PRIVATE);
40    }
41
42    @VisibleForTesting
43    public long getProvisioningId() {
44        return mSharedPreferences.getLong(KEY_PROVISIONING_ID, DEFAULT_PROVISIONING_ID);
45    }
46
47    /**
48     * Can assume the id is unique across all provisioning sessions
49     * @return a new provisioning id by incrementing the current id
50     */
51    public long incrementAndGetProvisioningId() {
52        synchronized (sWriteLock) {
53            long provisioningId = getProvisioningId();
54            provisioningId++;
55            // commit synchronously
56            mSharedPreferences.edit().putLong(KEY_PROVISIONING_ID, provisioningId).commit();
57            return provisioningId;
58        }
59    }
60}
61