1/*
2 * Copyright (C) 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 */
16
17package com.android.printservice.recommendation.plugin.hp;
18
19import android.net.nsd.NsdManager;
20import android.net.nsd.NsdServiceInfo;
21import android.util.Pair;
22import com.android.printservice.recommendation.util.NsdResolveQueue;
23
24import java.util.LinkedList;
25
26final class ServiceResolveQueue {
27
28    private final NsdManager mNsdManager;
29    private final LinkedList<Pair<NsdServiceInfo, ResolveCallback>> mQueue = new LinkedList<>();
30    private final Object mLock = new Object();
31
32    private static Object sLock = new Object();
33    private static ServiceResolveQueue sInstance = null;
34    private final NsdResolveQueue mNsdResolveQueue;
35    private Pair<NsdServiceInfo, ResolveCallback> mCurrentRequest = null;
36
37    public static void createInstance(NsdManager nsdManager) {
38        if (sInstance == null) sInstance = new ServiceResolveQueue(nsdManager);
39    }
40
41    public static ServiceResolveQueue getInstance(NsdManager nsdManager) {
42        synchronized (sLock) {
43            createInstance(nsdManager);
44            return sInstance;
45        }
46    }
47
48    public static void destroyInstance() {
49        sInstance = null;
50    }
51
52    public interface ResolveCallback {
53        void serviceResolved(NsdServiceInfo nsdServiceInfo);
54    }
55
56    public ServiceResolveQueue(NsdManager nsdManager) {
57        mNsdManager = nsdManager;
58        mNsdResolveQueue = NsdResolveQueue.getInstance();
59    }
60
61    public void queueRequest(NsdServiceInfo serviceInfo, ResolveCallback callback) {
62        synchronized (mLock) {
63            Pair<NsdServiceInfo, ResolveCallback> newRequest = Pair.create(serviceInfo, callback);
64            if (mQueue.contains(newRequest)) return;
65            mQueue.add(newRequest);
66            makeNextRequest();
67        }
68    }
69
70    public void removeRequest(NsdServiceInfo serviceInfo, ResolveCallback callback) {
71        synchronized (mLock) {
72            Pair<NsdServiceInfo, ResolveCallback> newRequest = Pair.create(serviceInfo, callback);
73            mQueue.remove(newRequest);
74            if ((mCurrentRequest != null) && newRequest.equals(mCurrentRequest)) mCurrentRequest = null;
75        }
76    }
77
78    private void makeNextRequest() {
79        synchronized (mLock) {
80            if (mCurrentRequest != null) return;
81            if (mQueue.isEmpty()) return;
82            mCurrentRequest = mQueue.removeFirst();
83            mNsdResolveQueue.resolve(mNsdManager, mCurrentRequest.first,
84                    new NsdManager.ResolveListener() {
85                @Override
86                public void onResolveFailed(NsdServiceInfo nsdServiceInfo, int i) {
87                    synchronized (mLock) {
88                        if (mCurrentRequest != null) mQueue.add(mCurrentRequest);
89                        makeNextRequest();
90                    }
91                }
92
93                @Override
94                public void onServiceResolved(NsdServiceInfo nsdServiceInfo) {
95                    synchronized (mLock) {
96                        if (mCurrentRequest != null) {
97                            mCurrentRequest.second.serviceResolved(nsdServiceInfo);
98                            mCurrentRequest = null;
99                        }
100                        makeNextRequest();
101                    }
102                }
103            });
104
105        }
106    }
107
108
109}
110