| /* |
| * Copyright (C) 2016 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.bips.discovery; |
| |
| import android.content.Context; |
| import android.net.nsd.NsdManager; |
| import android.net.nsd.NsdServiceInfo; |
| import android.os.Handler; |
| import android.util.Log; |
| |
| import java.util.LinkedList; |
| |
| /** |
| * Queues Nsd resolve requests to prevent multiple simultaneous requests to NsdManager |
| */ |
| public class NsdResolveQueue { |
| private static final String TAG = NsdResolveQueue.class.getSimpleName(); |
| private static final boolean DEBUG = false; |
| |
| private final NsdManager mNsdManager; |
| private final Handler mMainHandler; |
| |
| /** Current set of registered service info resolve attempts */ |
| private LinkedList<NsdResolveRequest> mResolveRequests = new LinkedList<>(); |
| |
| public NsdResolveQueue(Context context, NsdManager nsdManager) { |
| mNsdManager = nsdManager; |
| mMainHandler = new Handler(context.getMainLooper()); |
| } |
| |
| /** Return the {@link NsdManager} used by this queue */ |
| NsdManager getNsdManager() { |
| return mNsdManager; |
| } |
| |
| /** |
| * Resolve a serviceInfo or queue the request if there is a request currently in flight. |
| * |
| * @param serviceInfo The service info to resolve |
| * @param listener The listener to call back once the info is resolved. |
| */ |
| public NsdResolveRequest resolve(NsdServiceInfo serviceInfo, |
| NsdManager.ResolveListener listener) { |
| if (DEBUG) { |
| Log.d(TAG, "Adding resolve of " + serviceInfo.getServiceName() + " to queue size=" |
| + mResolveRequests.size()); |
| } |
| NsdResolveRequest request = new NsdResolveRequest(mNsdManager, serviceInfo, listener); |
| mResolveRequests.addLast(request); |
| if (mResolveRequests.size() == 1) { |
| resolveNextRequest(); |
| } |
| return request; |
| } |
| |
| /** |
| * Resolve the next request if there is one. |
| */ |
| private void resolveNextRequest() { |
| if (!mResolveRequests.isEmpty()) { |
| mResolveRequests.getFirst().start(); |
| } |
| } |
| |
| /** |
| * Holds a request to resolve a {@link NsdServiceInfo} |
| */ |
| class NsdResolveRequest implements NsdManager.ResolveListener { |
| private final NsdManager mNsdManager; |
| private final NsdServiceInfo mServiceInfo; |
| private final NsdManager.ResolveListener mListener; |
| private long mStartTime; |
| |
| private NsdResolveRequest(NsdManager nsdManager, |
| NsdServiceInfo serviceInfo, |
| NsdManager.ResolveListener listener) { |
| mNsdManager = nsdManager; |
| mServiceInfo = serviceInfo; |
| mListener = listener; |
| } |
| |
| private void start() { |
| mStartTime = System.currentTimeMillis(); |
| if (DEBUG) Log.d(TAG, "resolveService " + mServiceInfo.getServiceName()); |
| mNsdManager.resolveService(mServiceInfo, this); |
| } |
| |
| void cancel() { |
| // Note: resolve requests can only be cancelled if they have not yet begun |
| if (!mResolveRequests.isEmpty() && mResolveRequests.get(0) != this) { |
| mResolveRequests.remove(this); |
| } |
| } |
| |
| @Override |
| public void onResolveFailed(NsdServiceInfo serviceInfo, int errorCode) { |
| if (DEBUG) { |
| Log.d(TAG, "onResolveFailed " + serviceInfo.getServiceName() + " errorCode=" |
| + errorCode + " (" + (System.currentTimeMillis() - mStartTime) + " ms)"); |
| } |
| mMainHandler.post(() -> { |
| mListener.onResolveFailed(serviceInfo, errorCode); |
| mResolveRequests.pop(); |
| resolveNextRequest(); |
| }); |
| } |
| |
| @Override |
| public void onServiceResolved(NsdServiceInfo serviceInfo) { |
| if (DEBUG) { |
| Log.d(TAG, "onServiceResolved " + serviceInfo.getServiceName() |
| + " (" + (System.currentTimeMillis() - mStartTime) + " ms)"); |
| } |
| mMainHandler.post(() -> { |
| mListener.onServiceResolved(serviceInfo); |
| mResolveRequests.pop(); |
| resolveNextRequest(); |
| }); |
| } |
| } |
| } |