120 lines
4.0 KiB
Java
120 lines
4.0 KiB
Java
/*
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* Copyright 2016 Christian Basler
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package ch.dissem.apps.abit.service;
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import android.app.Service;
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import android.content.Intent;
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import android.os.Binder;
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import android.os.IBinder;
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import android.support.annotation.Nullable;
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import java.util.LinkedList;
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import java.util.Queue;
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import ch.dissem.apps.abit.notification.ProofOfWorkNotification;
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import ch.dissem.bitmessage.ports.MultiThreadedPOWEngine;
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import ch.dissem.bitmessage.ports.ProofOfWorkEngine;
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import static ch.dissem.apps.abit.notification.ProofOfWorkNotification.ONGOING_NOTIFICATION_ID;
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/**
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* The Proof of Work Service makes sure POW is done in a foreground process, so it shouldn't be
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* killed by the system before the nonce is found.
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*/
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public class ProofOfWorkService extends Service {
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// Object to use as a thread-safe lock
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private static final ProofOfWorkEngine engine = new MultiThreadedPOWEngine();
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private static final Queue<PowItem> queue = new LinkedList<>();
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private static boolean calculating;
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private ProofOfWorkNotification notification;
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@Override
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public void onCreate() {
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notification = new ProofOfWorkNotification(this);
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}
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@Nullable
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@Override
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public IBinder onBind(Intent intent) {
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return new PowBinder(this);
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}
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public static class PowBinder extends Binder {
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private final ProofOfWorkService service;
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private final ProofOfWorkNotification notification;
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private PowBinder(ProofOfWorkService service) {
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this.service = service;
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this.notification = service.notification;
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}
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void process(PowItem item) {
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synchronized (queue) {
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service.startService(new Intent(service, ProofOfWorkService.class));
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service.startForeground(ONGOING_NOTIFICATION_ID,
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notification.getNotification());
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if (!calculating) {
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calculating = true;
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service.calculateNonce(item);
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} else {
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queue.add(item);
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notification.update(queue.size()).show();
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}
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}
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}
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}
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static class PowItem {
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private final byte[] initialHash;
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private final byte[] targetValue;
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private final ProofOfWorkEngine.Callback callback;
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PowItem(byte[] initialHash, byte[] targetValue, ProofOfWorkEngine.Callback callback) {
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this.initialHash = initialHash;
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this.targetValue = targetValue;
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this.callback = callback;
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}
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}
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private void calculateNonce(final PowItem item) {
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engine.calculateNonce(item.initialHash, item.targetValue, new ProofOfWorkEngine.Callback() {
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@Override
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public void onNonceCalculated(byte[] initialHash, byte[] nonce) {
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try {
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item.callback.onNonceCalculated(initialHash, nonce);
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} finally {
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PowItem next;
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synchronized (queue) {
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next = queue.poll();
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if (next == null) {
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calculating = false;
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stopForeground(true);
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stopSelf();
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} else {
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notification.update(queue.size()).show();
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}
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}
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if (next != null) {
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calculateNonce(next);
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}
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}
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}
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});
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}
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}
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