packages/PrintSpooler/src/com/android/printspooler/PrintSpooler.java

/*
 * Copyright (C) 2013 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.printspooler;

import android.content.ComponentName;
import android.content.Context;
import android.os.AsyncTask;
import android.os.ParcelFileDescriptor;
import android.os.RemoteException;
import android.print.IPrintClient;
import android.print.IPrintSpoolerClient;
import android.print.IPrinterDiscoveryObserver;
import android.print.PrintAttributes;
import android.print.PrintJobInfo;
import android.print.PrintManager;
import android.print.PrintDocumentInfo;
import android.print.PrinterId;
import android.util.AtomicFile;
import android.util.Log;
import android.util.Slog;
import android.util.Xml;

import com.android.internal.util.FastXmlSerializer;

import libcore.io.IoUtils;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlSerializer;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class PrintSpooler {

    private static final String LOG_TAG = PrintSpooler.class.getSimpleName();

    private static final boolean DEBUG_PRINT_JOB_LIFECYCLE = false;

    private static final boolean DEBUG_PERSISTENCE = false;

    private static final boolean PERSISTNECE_MANAGER_ENABLED = false;

    private static final String PRINT_FILE_EXTENSION = "pdf";

    private static int sPrintJobIdCounter;

    private static final Object sLock = new Object();

    private static PrintSpooler sInstance;

    private final Object mLock = new Object();

    private final List<PrintJobInfo> mPrintJobs = new ArrayList<PrintJobInfo>();

    private final PersistenceManager mPersistanceManager;

    private final Context mContext;

    public IPrintSpoolerClient mClient;

    public static PrintSpooler getInstance(Context context) {
        synchronized (sLock) {
            if (sInstance == null) {
                sInstance = new PrintSpooler(context);
            }
            return sInstance;
        }
    }

    private PrintSpooler(Context context) {
        mContext = context;
        mPersistanceManager = new PersistenceManager();
        mPersistanceManager.readStateLocked();
    }

    public void setCleint(IPrintSpoolerClient client) {
        synchronized (mLock) {
            mClient = client;
        }
    }

    public void startPrinterDiscovery(IPrinterDiscoveryObserver observer) {
        IPrintSpoolerClient client = null;
        synchronized (mLock) {
            client = mClient;
        }
        if (client != null) {
            try {
                client.onStartPrinterDiscovery(observer);
            } catch (RemoteException re) {
                Log.e(LOG_TAG, "Error notifying start printer discovery.", re);
            }
        }
    }

    public void stopPrinterDiscovery() {
        IPrintSpoolerClient client = null;
        synchronized (mLock) {
            client = mClient;
        }
        if (client != null) {
            try {
                client.onStopPrinterDiscovery();
            } catch (RemoteException re) {
                Log.e(LOG_TAG, "Error notifying stop printer discovery.", re);
            }
        }
    }

    public List<PrintJobInfo> getPrintJobs(ComponentName componentName, int state, int appId) {
        synchronized (mLock) {
            List<PrintJobInfo> foundPrintJobs = null;
            final int printJobCount = mPrintJobs.size();
            for (int i = 0; i < printJobCount; i++) {
                PrintJobInfo printJob = mPrintJobs.get(i);
                PrinterId printerId = printJob.getPrinterId();
                final boolean sameComponent = (componentName == null
                        || (printerId != null
                        && componentName.equals(printerId.getService())));
                final boolean sameAppId = appId == PrintManager.APP_ID_ANY
                        || printJob.getAppId() == appId;
                final boolean sameState = state == PrintJobInfo.STATE_ANY
                        || state == printJob.getState();
                if (sameComponent && sameAppId && sameState) {
                    if (foundPrintJobs == null) {
                        foundPrintJobs = new ArrayList<PrintJobInfo>();
                    }
                    foundPrintJobs.add(printJob);
                }
            }
            return foundPrintJobs;
        }
    }

    public PrintJobInfo getPrintJob(int printJobId, int appId) {
        synchronized (mLock) {
            final int printJobCount = mPrintJobs.size();
            for (int i = 0; i < printJobCount; i++) {
                PrintJobInfo printJob = mPrintJobs.get(i);
                if (printJob.getId() == printJobId
                        && (appId == PrintManager.APP_ID_ANY || appId == printJob.getAppId())) {
                    return printJob;
                }
             }
            return null;
        }
    }

    public boolean cancelPrintJob(int printJobId, int appId) {
        synchronized (mLock) {
            PrintJobInfo printJob = getPrintJob(printJobId, appId);
            if (printJob != null) {
                switch (printJob.getState()) {
                    case PrintJobInfo.STATE_CREATED:
                    case PrintJobInfo.STATE_QUEUED: {
                        setPrintJobState(printJobId, PrintJobInfo.STATE_CANCELED);
                    } return true;
                }
            }
            return false;
        }
    }

    public PrintJobInfo createPrintJob(CharSequence label, IPrintClient client,
            PrintAttributes attributes, int appId) {
        synchronized (mLock) {
            final int printJobId = generatePrintJobIdLocked();
            PrintJobInfo printJob = new PrintJobInfo();
            printJob.setId(printJobId);
            printJob.setAppId(appId);
            printJob.setLabel(label);
            printJob.setAttributes(attributes);

            addPrintJobLocked(printJob);
            setPrintJobState(printJobId, PrintJobInfo.STATE_CREATED);

            return printJob;
        }
    }

    public void notifyClientForActivteJobs() {
        IPrintSpoolerClient client = null;
        Map<ComponentName, List<PrintJobInfo>> activeJobsPerServiceMap =
                new HashMap<ComponentName, List<PrintJobInfo>>();

        synchronized(mLock) {
            if (mClient == null) {
                throw new IllegalStateException("Client cannot be null.");
            }
            client = mClient;

            final int printJobCount = mPrintJobs.size();
            for (int i = 0; i < printJobCount; i++) {
                PrintJobInfo printJob = mPrintJobs.get(i);
                switch (printJob.getState()) {
                    case PrintJobInfo.STATE_CREATED: {
                        /* skip - not ready to be handled by a service */
                    } break;

                    case PrintJobInfo.STATE_QUEUED:
                    case PrintJobInfo.STATE_STARTED: {
                        ComponentName service = printJob.getPrinterId().getService();
                        List<PrintJobInfo> jobsPerService = activeJobsPerServiceMap.get(service);
                        if (jobsPerService == null) {
                            jobsPerService = new ArrayList<PrintJobInfo>();
                            activeJobsPerServiceMap.put(service, jobsPerService);
                        }
                        jobsPerService.add(printJob);
                    } break;

                    default: {
                        ComponentName service = printJob.getPrinterId().getService();
                        if (!activeJobsPerServiceMap.containsKey(service)) {
                            activeJobsPerServiceMap.put(service, null);
                        }
                    }
                }
            }
        }

        boolean allPrintJobsHandled = true;

        for (Map.Entry<ComponentName, List<PrintJobInfo>> entry
                : activeJobsPerServiceMap.entrySet()) {
            ComponentName service = entry.getKey();
            List<PrintJobInfo> printJobs = entry.getValue();

            if (printJobs != null) {
                allPrintJobsHandled = false;
                final int printJobCount = printJobs.size();
                for (int i = 0; i < printJobCount; i++) {
                    PrintJobInfo printJob = printJobs.get(i);
                    if (printJob.getState() == PrintJobInfo.STATE_QUEUED) {
                        callOnPrintJobQueuedQuietly(client, printJob);
                    }
                }
            } else {
                callOnAllPrintJobsForServiceHandledQuietly(client, service);
            }
        }

        if (allPrintJobsHandled) {
            callOnAllPrintJobsHandledQuietly(client);
        }
    }

    private int generatePrintJobIdLocked() {
        int printJobId = sPrintJobIdCounter++;
        while (isDuplicatePrintJobId(printJobId)) {
            printJobId = sPrintJobIdCounter++;
        }
        return printJobId;
    }

    private boolean isDuplicatePrintJobId(int printJobId) {
        final int printJobCount = mPrintJobs.size();
        for (int j = 0; j < printJobCount; j++) {
            PrintJobInfo printJob = mPrintJobs.get(j);
            if (printJob.getId() == printJobId) {
                return true;
            }
        }
        return false;
    }

    @SuppressWarnings("resource")
    public boolean writePrintJobData(ParcelFileDescriptor fd, int printJobId) {
        synchronized (mLock) {
            FileInputStream in = null;
            FileOutputStream out = null;
            try {
                PrintJobInfo printJob = getPrintJob(printJobId, PrintManager.APP_ID_ANY);
                if (printJob != null) {
                    File file = generateFileForPrintJob(printJobId);
                    in = new FileInputStream(file);
                    out = new FileOutputStream(fd.getFileDescriptor());
                    final byte[] buffer = new byte[8192];
                    while (true) {
                        final int readByteCount = in.read(buffer);
                        if (readByteCount < 0) {
                            return true;
                        }
                        out.write(buffer, 0, readByteCount);
                    }
                }
            } catch (FileNotFoundException fnfe) {
                Log.e(LOG_TAG, "Error writing print job data!", fnfe);
            } catch (IOException ioe) {
                Log.e(LOG_TAG, "Error writing print job data!", ioe);
            } finally {
                IoUtils.closeQuietly(in);
                IoUtils.closeQuietly(out);
                IoUtils.closeQuietly(fd);
            }
        }
        return false;
    }

    public File generateFileForPrintJob(int printJobId) {
        return new File(mContext.getFilesDir(), "print_job_"
                + printJobId + "." + PRINT_FILE_EXTENSION);
    }

    private void addPrintJobLocked(PrintJobInfo printJob) {
        mPrintJobs.add(printJob);
        if (DEBUG_PRINT_JOB_LIFECYCLE) {
            Slog.i(LOG_TAG, "[ADD] " + printJob);
        }
    }

    private void removePrintJobLocked(PrintJobInfo printJob) {
        if (mPrintJobs.remove(printJob)) {
            generateFileForPrintJob(printJob.getId()).delete();
            if (DEBUG_PRINT_JOB_LIFECYCLE) {
                Slog.i(LOG_TAG, "[REMOVE] " + printJob);
            }
        }
    }

    public boolean setPrintJobState(int printJobId, int state) {
        boolean success = false;

        boolean allPrintJobsHandled = false;
        boolean allPrintJobsForServiceHandled = false;

        IPrintSpoolerClient client = null;
        PrintJobInfo queuedPrintJob = null;
        PrintJobInfo removedPrintJob = null;

        synchronized (mLock) {
            if (mClient == null) {
                throw new IllegalStateException("Client cannot be null.");
            }
            client = mClient;

            PrintJobInfo printJob = getPrintJob(printJobId, PrintManager.APP_ID_ANY);
            if (printJob != null && printJob.getState() < state) {
                success = true;
                printJob.setState(state);
                // TODO: Update notifications.
                switch (state) {
                    case PrintJobInfo.STATE_COMPLETED:
                    case PrintJobInfo.STATE_CANCELED: {
                        removedPrintJob = printJob;
                        removePrintJobLocked(printJob);

                        // No printer means creation of a print job was cancelled,
                        // therefore the state of the spooler did not change and no
                        // notifications are needed. We also do not need to persist
                        // the state.
                        PrinterId printerId = printJob.getPrinterId();
                        if (printerId == null) {
                            return true;
                        }

                        allPrintJobsHandled = !hasActivePrintJobsLocked();
                        allPrintJobsForServiceHandled = !hasActivePrintJobsForServiceLocked(
                                printerId.getService());
                    } break;

                    case PrintJobInfo.STATE_QUEUED: {
                        queuedPrintJob = new PrintJobInfo(printJob);
                    } break;
                }
                if (DEBUG_PRINT_JOB_LIFECYCLE) {
                    Slog.i(LOG_TAG, "[STATUS CHANGED] " + printJob);
                }
                mPersistanceManager.writeStateLocked();
            }
        }

        if (queuedPrintJob != null) {
            callOnPrintJobQueuedQuietly(client, queuedPrintJob);
        }

        if (allPrintJobsForServiceHandled) {
            callOnAllPrintJobsForServiceHandledQuietly(client,
                        removedPrintJob.getPrinterId().getService());
        }

        if (allPrintJobsHandled) {
            callOnAllPrintJobsHandledQuietly(client);
        }

        return success;
    }

    private void callOnPrintJobQueuedQuietly(IPrintSpoolerClient client,
            PrintJobInfo printJob) {
        try {
            client.onPrintJobQueued(printJob);
        } catch (RemoteException re) {
            Slog.e(LOG_TAG, "Error notify for a queued print job.", re);
        }
    }

    private void callOnAllPrintJobsForServiceHandledQuietly(IPrintSpoolerClient client,
            ComponentName service) {
        try {
            client.onAllPrintJobsForServiceHandled(service);
        } catch (RemoteException re) {
            Slog.e(LOG_TAG, "Error notify for all print jobs per service handled.", re);
        }
    }

    private void callOnAllPrintJobsHandledQuietly(IPrintSpoolerClient client) {
        try {
            client.onAllPrintJobsHandled();
        } catch (RemoteException re) {
            Slog.e(LOG_TAG, "Error notify for all print job handled.", re);
        }
    }

    private boolean hasActivePrintJobsLocked() {
        final int printJobCount = mPrintJobs.size();
        for (int i = 0; i < printJobCount; i++) {
            PrintJobInfo printJob = mPrintJobs.get(i);
            switch (printJob.getState()) {
                case PrintJobInfo.STATE_QUEUED:
                case PrintJobInfo.STATE_STARTED: {
                    return true;
                }
            }
        }
        return false;
    }

    private boolean hasActivePrintJobsForServiceLocked(ComponentName service) {
        final int printJobCount = mPrintJobs.size();
        for (int i = 0; i < printJobCount; i++) {
            PrintJobInfo printJob = mPrintJobs.get(i);
            switch (printJob.getState()) {
                case PrintJobInfo.STATE_QUEUED:
                case PrintJobInfo.STATE_STARTED: {
                    if (printJob.getPrinterId().getService().equals(service)) {
                        return true;
                    }
                } break;
            }
        }
        return false;
    }

    public boolean setPrintJobTag(int printJobId, String tag) {
        synchronized (mLock) {
            PrintJobInfo printJob = getPrintJob(printJobId, PrintManager.APP_ID_ANY);
            if (printJob != null) {
                printJob.setTag(tag);
                mPersistanceManager.writeStateLocked();
                return true;
            }
        }
        return false;
    }

    public final boolean setPrintJobPrintDocumentInfo(int printJobId, PrintDocumentInfo info) {
        synchronized (mLock) {
            PrintJobInfo printJob = getPrintJob(printJobId, PrintManager.APP_ID_ANY);
            if (printJob != null) {
                printJob.setDocumentInfo(info);
                mPersistanceManager.writeStateLocked();
                return true;
            }
        }
        return false;
    }

    public void setPrintJobAttributes(int printJobId, PrintAttributes attributes) {
        synchronized (mLock) {
            PrintJobInfo printJob = getPrintJob(printJobId, PrintManager.APP_ID_ANY);
            if (printJob != null) {
                printJob.setAttributes(attributes);
                mPersistanceManager.writeStateLocked();
            }
        }
    }

    public void setPrintJobPrinterId(int printJobId, PrinterId printerId) {
        synchronized (mLock) {
            PrintJobInfo printJob = getPrintJob(printJobId, PrintManager.APP_ID_ANY);
            if (printJob != null) {
                printJob.setPrinterId(printerId);
                mPersistanceManager.writeStateLocked();
            }
        }
    }

    private final class PersistenceManager {
        private static final String PERSIST_FILE_NAME = "print_spooler_state.xml";

        private static final String TAG_SPOOLER = "spooler";
        private static final String TAG_JOB = "job";
        private static final String TAG_ID = "id";
        private static final String TAG_TAG = "tag";
        private static final String TAG_APP_ID = "app-id";
        private static final String TAG_STATE = "state";
        private static final String TAG_ATTRIBUTES = "attributes";
        private static final String TAG_LABEL = "label";
        private static final String TAG_PRINTER = "printer";

        private static final String ATTRIBUTE_MEDIA_SIZE = "mediaSize";
        private static final String ATTRIBUTE_RESOLUTION = "resolution";
        private static final String ATTRIBUTE_MARGINS = "margins";
        private static final String ATTRIBUTE_INPUT_TRAY = "inputTray";
        private static final String ATTRIBUTE_OUTPUT_TRAY = "outputTray";
        private static final String ATTRIBUTE_DUPLEX_MODE = "duplexMode";
        private static final String ATTRIBUTE_COLOR_MODE = "colorMode";
        private static final String ATTRIBUTE_FITTING_MODE = "fittingMode";
        private static final String ATTRIBUTE_ORIENTATION = "orientation";

        private final AtomicFile mStatePersistFile;

        private boolean mWriteStateScheduled;

        private PersistenceManager() {
            mStatePersistFile = new AtomicFile(new File(mContext.getFilesDir(),
                    PERSIST_FILE_NAME));
        }

        public void writeStateLocked() {
            // TODO: Implement persistence of PrintableInfo
            if (!PERSISTNECE_MANAGER_ENABLED) {
                return;
            }
            if (mWriteStateScheduled) {
                return;
            }
            mWriteStateScheduled = true;
            new AsyncTask<Void, Void, Void>() {
                @Override
                protected Void doInBackground(Void... params) {
                    synchronized (mLock) {
                        mWriteStateScheduled = false;
                        doWriteStateLocked();
                    }
                    return null;
                }
            }.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, (Void[]) null);
        }

        private void doWriteStateLocked() {
            FileOutputStream out = null;
            try {
                out = mStatePersistFile.startWrite();

                XmlSerializer serializer = new FastXmlSerializer();
                serializer.setOutput(out, "utf-8");
                serializer.startDocument(null, true);
                serializer.startTag(null, TAG_SPOOLER);

                List<PrintJobInfo> printJobs = mPrintJobs;

                final int printJobCount = printJobs.size();
                for (int j = 0; j < printJobCount; j++) {
                    PrintJobInfo printJob = printJobs.get(j);

                    final int state = printJob.getState();
                    if (state < PrintJobInfo.STATE_QUEUED
                            || state > PrintJobInfo.STATE_FAILED) {
                        continue;
                    }

                    serializer.startTag(null, TAG_JOB);

                    serializer.startTag(null, TAG_ID);
                    serializer.text(String.valueOf(printJob.getId()));
                    serializer.endTag(null, TAG_ID);

                    serializer.startTag(null, TAG_TAG);
                    serializer.text(printJob.getTag());
                    serializer.endTag(null, TAG_TAG);

                    serializer.startTag(null, TAG_APP_ID);
                    serializer.text(String.valueOf(printJob.getAppId()));
                    serializer.endTag(null, TAG_APP_ID);

                    serializer.startTag(null, TAG_LABEL);
                    serializer.text(printJob.getLabel().toString());
                    serializer.endTag(null, TAG_LABEL);

                    serializer.startTag(null, TAG_STATE);
                    serializer.text(String.valueOf(printJob.getState()));
                    serializer.endTag(null, TAG_STATE);

                    serializer.startTag(null, TAG_PRINTER);
                    serializer.text(printJob.getPrinterId().flattenToString());
                    serializer.endTag(null, TAG_PRINTER);

                    PrintAttributes attributes = printJob.getAttributes();
                    if (attributes != null) {
                        serializer.startTag(null, TAG_ATTRIBUTES);

                            //TODO: Implement persistence of the attributes below.

//                            MediaSize mediaSize = attributes.getMediaSize();
//                            if (mediaSize != null) {
//                                serializer.attribute(null, ATTRIBUTE_MEDIA_SIZE,
//                                        mediaSize.flattenToString());
//                            }
//
//                            Resolution resolution = attributes.getResolution();
//                            if (resolution != null) {
//                                serializer.attribute(null, ATTRIBUTE_RESOLUTION,
//                                        resolution.flattenToString());
//                            }
//
//                            Margins margins = attributes.getMargins();
//                            if (margins != null) {
//                                serializer.attribute(null, ATTRIBUTE_MARGINS,
//                                        margins.flattenToString());
//                            }
//
//                            Tray inputTray = attributes.getInputTray();
//                            if (inputTray != null) {
//                                serializer.attribute(null, ATTRIBUTE_INPUT_TRAY,
//                                        inputTray.flattenToString());
//                            }
//
//                            Tray outputTray = attributes.getOutputTray();
//                            if (outputTray != null) {
//                                serializer.attribute(null, ATTRIBUTE_OUTPUT_TRAY,
//                                        outputTray.flattenToString());
//                            }

                        final int duplexMode = attributes.getDuplexMode();
                        if (duplexMode > 0) {
                            serializer.attribute(null, ATTRIBUTE_DUPLEX_MODE,
                                    String.valueOf(duplexMode));
                        }

                        final int colorMode = attributes.getColorMode();
                        if (colorMode > 0) {
                            serializer.attribute(null, ATTRIBUTE_COLOR_MODE,
                                    String.valueOf(colorMode));
                        }

                        final int fittingMode = attributes.getFittingMode();
                        if (fittingMode > 0) {
                            serializer.attribute(null, ATTRIBUTE_FITTING_MODE,
                                    String.valueOf(fittingMode));
                        }

                        final int orientation = attributes.getOrientation();
                        if (orientation > 0) {
                            serializer.attribute(null, ATTRIBUTE_ORIENTATION,
                                    String.valueOf(orientation));
                        }

                        serializer.endTag(null, TAG_ATTRIBUTES);
                    }

                    serializer.endTag(null, TAG_JOB);

                    if (DEBUG_PERSISTENCE) {
                        Log.i(LOG_TAG, "[PERSISTED] " + printJob);
                    }
                }

                serializer.endTag(null, TAG_SPOOLER);
                serializer.endDocument();
                mStatePersistFile.finishWrite(out);
            } catch (IOException e) {
                Slog.w(LOG_TAG, "Failed to write state, restoring backup.", e);
                mStatePersistFile.failWrite(out);
            } finally {
                if (out != null) {
                    try {
                        out.close();
                    } catch (IOException ioe) {
                        /* ignore */
                    }
                }
            }
        }

        public void readStateLocked() {
            if (!PERSISTNECE_MANAGER_ENABLED) {
                return;
            }
            FileInputStream in = null;
            try {
                in = mStatePersistFile.openRead();
            } catch (FileNotFoundException e) {
                Log.i(LOG_TAG, "No existing print spooler state.");
                return;
            }
            try {
                XmlPullParser parser = Xml.newPullParser();
                parser.setInput(in, null);
                parseState(parser);
            } catch (IllegalStateException ise) {
                Slog.w(LOG_TAG, "Failed parsing " + ise);
            } catch (NullPointerException npe) {
                Slog.w(LOG_TAG, "Failed parsing " + npe);
            } catch (NumberFormatException nfe) {
                Slog.w(LOG_TAG, "Failed parsing " + nfe);
            } catch (XmlPullParserException xppe) {
                Slog.w(LOG_TAG, "Failed parsing " + xppe);
            } catch (IOException ioe) {
                Slog.w(LOG_TAG, "Failed parsing " + ioe);
            } catch (IndexOutOfBoundsException iobe) {
                Slog.w(LOG_TAG, "Failed parsing " + iobe);
            } finally {
                try {
                    in.close();
                } catch (IOException ioe) {
                    /* ignore */
                }
            }
        }

        private void parseState(XmlPullParser parser)
                throws IOException, XmlPullParserException {
            parser.next();
            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.START_TAG, TAG_SPOOLER);
            parser.next();

            while (parsePrintJob(parser)) {
                parser.next();
            }

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_SPOOLER);
        }

        private boolean parsePrintJob(XmlPullParser parser)
                throws IOException, XmlPullParserException {
            skipEmptyTextTags(parser);
            if (!accept(parser, XmlPullParser.START_TAG, TAG_JOB)) {
                return false;
            }
            parser.next();

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.START_TAG, TAG_ID);
            parser.next();
            final int printJobId = Integer.parseInt(parser.getText());
            parser.next();
            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_ID);
            parser.next();

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.START_TAG, TAG_TAG);
            parser.next();
            String tag = parser.getText();
            parser.next();
            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_TAG);
            parser.next();

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.START_TAG, TAG_APP_ID);
            parser.next();
            final int appId = Integer.parseInt(parser.getText());
            parser.next();
            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_APP_ID);
            parser.next();

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.START_TAG, TAG_LABEL);
            parser.next();
            String label = parser.getText();
            parser.next();
            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_LABEL);
            parser.next();

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.START_TAG, TAG_STATE);
            parser.next();
            final int state = Integer.parseInt(parser.getText());
            parser.next();
            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_STATE);
            parser.next();

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.START_TAG, TAG_PRINTER);
            parser.next();
            PrinterId printerId = PrinterId.unflattenFromString(parser.getText());
            parser.next();
            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_PRINTER);
            parser.next();

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.START_TAG, TAG_ATTRIBUTES);

            final int attributeCount = parser.getAttributeCount();
            PrintAttributes attributes = null;
            if (attributeCount > 0) {
                PrintAttributes.Builder builder = new PrintAttributes.Builder();

                // TODO: Implement reading of the attributes below.

//                String mediaSize = parser.getAttributeValue(null, ATTRIBUTE_MEDIA_SIZE);
//                if (mediaSize != null) {
//                    builder.setMediaSize(MediaSize.unflattenFromString(mediaSize));
//                }
//
//                String resolution = parser.getAttributeValue(null, ATTRIBUTE_RESOLUTION);
//                if (resolution != null) {
//                    builder.setMediaSize(Resolution.unflattenFromString(resolution));
//                }
//
//                String margins = parser.getAttributeValue(null, ATTRIBUTE_MARGINS);
//                if (margins != null) {
//                    builder.setMediaSize(Margins.unflattenFromString(margins));
//                }
//
//                String inputTray = parser.getAttributeValue(null, ATTRIBUTE_INPUT_TRAY);
//                if (inputTray != null) {
//                    builder.setMediaSize(Tray.unflattenFromString(inputTray));
//                }
//
//                String outputTray = parser.getAttributeValue(null, ATTRIBUTE_OUTPUT_TRAY);
//                if (outputTray != null) {
//                    builder.setMediaSize(Tray.unflattenFromString(outputTray));
//                }
//
//                String duplexMode = parser.getAttributeValue(null, ATTRIBUTE_DUPLEX_MODE);
//                if (duplexMode != null) {
//                    builder.setDuplexMode(Integer.parseInt(duplexMode));
//                }

                String colorMode = parser.getAttributeValue(null, ATTRIBUTE_COLOR_MODE);
                if (colorMode != null) {
                    builder.setColorMode(Integer.parseInt(colorMode));
                }

                String fittingMode = parser.getAttributeValue(null, ATTRIBUTE_COLOR_MODE);
                if (fittingMode != null) {
                    builder.setFittingMode(Integer.parseInt(fittingMode));
                }
            }
            parser.next();
            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_ATTRIBUTES);
            parser.next();

            PrintJobInfo printJob = new PrintJobInfo();
            printJob.setId(printJobId);
            printJob.setTag(tag);
            printJob.setAppId(appId);
            printJob.setLabel(label);
            printJob.setState(state);
            printJob.setAttributes(attributes);
            printJob.setPrinterId(printerId);

            mPrintJobs.add(printJob);

            if (DEBUG_PERSISTENCE) {
                Log.i(LOG_TAG, "[RESTORED] " + printJob);
            }

            skipEmptyTextTags(parser);
            expect(parser, XmlPullParser.END_TAG, TAG_JOB);

            return true;
        }

        private void expect(XmlPullParser parser, int type, String tag)
                throws IOException, XmlPullParserException {
            if (!accept(parser, type, tag)) {
                throw new XmlPullParserException("Exepected event: " + type
                        + " and tag: " + tag + " but got event: " + parser.getEventType()
                        + " and tag:" + parser.getName());
            }
        }

        private void skipEmptyTextTags(XmlPullParser parser)
                throws IOException, XmlPullParserException {
            while (accept(parser, XmlPullParser.TEXT, null)
                    && "\n".equals(parser.getText())) {
                parser.next();
            }
        }

        private boolean accept(XmlPullParser parser, int type, String tag)
                throws IOException, XmlPullParserException {
            if (parser.getEventType() != type) {
                return false;
            }
            if (tag != null) {
                if (!tag.equals(parser.getName())) {
                    return false;
                }
            } else if (parser.getName() != null) {
                return false;
            }
            return true;
        }
    }
}