1 files changed, 575 insertions, 0 deletions
diff --git a/packages/PrintSpooler/src/com/android/printspooler/FusedPrintersProvider.java b/packages/PrintSpooler/src/com/android/printspooler/FusedPrintersProvider.java
new file mode 100644
index 0000000..6bad5b3
--- /dev/null
+++ b/packages/PrintSpooler/src/com/android/printspooler/FusedPrintersProvider.java
@@ -0,0 +1,575 @@
+/*
+ * 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.content.Loader;
+import android.os.AsyncTask;
+import android.os.Build;
+import android.print.PrinterId;
+import android.print.PrinterInfo;
+import android.util.ArrayMap;
+import android.util.AtomicFile;
+import android.util.Log;
+import android.util.Slog;
+import android.util.Xml;
+
+import com.android.internal.util.FastXmlSerializer;
+import com.android.printspooler.PrintSpoolerService.PrinterDiscoverySession;
+
+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.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * This class is responsible for loading printers by doing discovery
+ * and merging the discovered printers with the previously used ones.
+ */
+public class FusedPrintersProvider extends Loader<List<PrinterInfo>> {
+    private static final String LOG_TAG = "FusedPrintersProvider";
+
+    private static final boolean DEBUG = true && Build.IS_DEBUGGABLE;
+
+    private static final double WEIGHT_DECAY_COEFFICIENT = 0.95f;
+
+    private static final int MAX_HISTORY_LENGTH = 50;
+
+    private static final int MAX_HISTORICAL_PRINTER_COUNT = 4;
+
+    private final Map<PrinterId, PrinterInfo> mPrinters =
+            new LinkedHashMap<PrinterId, PrinterInfo>();
+
+    private final PersistenceManager mPersistenceManager;
+
+    private PrinterDiscoverySession mDiscoverySession;
+
+    private List<PrinterInfo> mFavoritePrinters;
+
+    public FusedPrintersProvider(Context context) {
+        super(context);
+        mPersistenceManager = new PersistenceManager(context);
+    }
+
+    public void addHistoricalPrinter(PrinterInfo printer) {
+        mPersistenceManager.addPrinterAndWritePrinterHistory(printer);
+    }
+
+    public List<PrinterInfo> getPrinters() {
+        return new ArrayList<PrinterInfo>(mPrinters.values());
+    }
+
+    @Override
+    public void deliverResult(List<PrinterInfo> printers) {
+        if (isStarted()) {
+            super.deliverResult(printers);
+        }
+    }
+
+    @Override
+    protected void onStartLoading() {
+        if (DEBUG) {
+            Log.i(LOG_TAG, "onStartLoading()");
+        }
+        // The contract is that if we already have a valid,
+        // result the we have to deliver it immediately.
+        if (!mPrinters.isEmpty()) {
+            deliverResult(new ArrayList<PrinterInfo>(mPrinters.values()));
+        }
+        // If the data has changed since the last load
+        // or is not available, start a load.
+        if (takeContentChanged() || mPrinters.isEmpty()) {
+            onForceLoad();
+        }
+    }
+
+    @Override
+    protected void onStopLoading() {
+        if (DEBUG) {
+            Log.i(LOG_TAG, "onStopLoading()");
+        }
+        onCancelLoad();
+    }
+
+    @Override
+    protected void onForceLoad() {
+        if (DEBUG) {
+            Log.i(LOG_TAG, "onForceLoad()");
+        }
+        onCancelLoad();
+        loadInternal();
+    }
+
+    private void loadInternal() {
+        if (mDiscoverySession == null) {
+            mDiscoverySession = new MyPrinterDiscoverySession();
+            mPersistenceManager.readPrinterHistory();
+        }
+        if (mPersistenceManager.isReadHistoryCompleted()
+                && !mDiscoverySession.isStarted()) {
+            final int favoriteCount = Math.min(MAX_HISTORICAL_PRINTER_COUNT,
+                    mFavoritePrinters.size());
+            List<PrinterId> printerIds = new ArrayList<PrinterId>(favoriteCount);
+            for (int i = 0; i < favoriteCount; i++) {
+                printerIds.add(mFavoritePrinters.get(i).getId());
+            }
+            mDiscoverySession.startPrinterDisovery(printerIds);
+        }
+    }
+
+    @Override
+    protected boolean onCancelLoad() {
+        if (DEBUG) {
+            Log.i(LOG_TAG, "onCancelLoad()");
+        }
+        return cancelInternal();
+    }
+
+    private boolean cancelInternal() {
+        if (mDiscoverySession != null && mDiscoverySession.isStarted()) {
+            mDiscoverySession.stopPrinterDiscovery();
+            return true;
+        } else if (mPersistenceManager.isReadHistoryInProgress()) {
+            return mPersistenceManager.stopReadPrinterHistory();
+        }
+        return false;
+    }
+
+    @Override
+    protected void onReset() {
+        if (DEBUG) {
+            Log.i(LOG_TAG, "onReset()");
+        }
+        onStopLoading();
+        mPrinters.clear();
+        if (mDiscoverySession != null) {
+            mDiscoverySession.destroy();
+            mDiscoverySession = null;
+        }
+    }
+
+    @Override
+    protected void onAbandon() {
+        if (DEBUG) {
+            Log.i(LOG_TAG, "onAbandon()");
+        }
+        onStopLoading();
+    }
+
+    public void refreshPrinter(PrinterId printerId) {
+        if (isStarted() && mDiscoverySession != null && mDiscoverySession.isStarted()) {
+            mDiscoverySession.requestPrinterUpdated(printerId);
+        }
+    }
+
+    private final class MyPrinterDiscoverySession extends PrinterDiscoverySession {
+
+        @Override
+        public void onPrintersAdded(List<PrinterInfo> printers) {
+            if (DEBUG) {
+                Log.i(LOG_TAG, "MyPrinterDiscoverySession#onPrintersAdded()");
+            }
+            boolean printersAdded = false;
+            final int addedPrinterCount = printers.size();
+            for (int i = 0; i < addedPrinterCount; i++) {
+                PrinterInfo printer = printers.get(i);
+                if (!mPrinters.containsKey(printer.getId())) {
+                    mPrinters.put(printer.getId(), printer);
+                    printersAdded = true;
+                }
+            }
+            if (printersAdded) {
+                deliverResult(new ArrayList<PrinterInfo>(mPrinters.values()));
+            }
+        }
+
+        @Override
+        public void onPrintersRemoved(List<PrinterId> printerIds) {
+            if (DEBUG) {
+                Log.i(LOG_TAG, "MyPrinterDiscoverySession#onPrintersRemoved()");
+            }
+            boolean removedPrinters = false;
+            final int removedPrinterCount = printerIds.size();
+            for (int i = 0; i < removedPrinterCount; i++) {
+                PrinterId removedPrinterId = printerIds.get(i);
+                if (mPrinters.remove(removedPrinterId) != null) {
+                    removedPrinters = true;
+                }
+            }
+            if (removedPrinters) {
+                deliverResult(new ArrayList<PrinterInfo>(mPrinters.values()));
+            }
+        }
+
+        @Override
+        public void onPrintersUpdated(List<PrinterInfo> printers) {
+            if (DEBUG) {
+                Log.i(LOG_TAG, "MyPrinterDiscoverySession#onPrintersUpdated()");
+            }
+            boolean updatedPrinters = false;
+            final int updatedPrinterCount = printers.size();
+            for (int i = 0; i < updatedPrinterCount; i++) {
+                PrinterInfo updatedPrinter = printers.get(i);
+                if (mPrinters.containsKey(updatedPrinter.getId())) {
+                    mPrinters.put(updatedPrinter.getId(), updatedPrinter);
+                    updatedPrinters = true;
+                }
+            }
+            if (updatedPrinters) {
+                deliverResult(new ArrayList<PrinterInfo>(mPrinters.values()));
+            }
+        }
+    }
+
+    private final class PersistenceManager {
+        private static final String PERSIST_FILE_NAME = "printer_history.xml";
+
+        private static final String TAG_PRINTERS = "printers";
+
+        private static final String TAG_PRINTER = "printer";
+        private static final String TAG_PRINTER_ID = "printerId";
+
+        private static final String ATTR_LOCAL_ID = "localId";
+        private static final String ATTR_SERVICE_NAME = "serviceName";
+
+        private static final String ATTR_NAME = "name";
+        private static final String ATTR_DESCRIPTION = "description";
+        private static final String ATTR_STATUS = "status";
+
+        private final AtomicFile mStatePersistFile;
+
+        private List<PrinterInfo> mHistoricalPrinters;
+
+        private boolean mReadHistoryCompleted;
+        private boolean mReadHistoryInProgress;
+
+        private final AsyncTask<Void, Void, List<PrinterInfo>> mReadTask =
+                new AsyncTask<Void, Void, List<PrinterInfo>>() {
+            @Override
+            protected List<PrinterInfo> doInBackground(Void... args) {
+               return doReadPrinterHistory();
+            }
+
+            @Override
+            protected void onPostExecute(List<PrinterInfo> printers) {
+                if (DEBUG) {
+                    Log.i(LOG_TAG, "read history completed");
+                }
+
+                mHistoricalPrinters = printers;
+
+                // Compute the favorite printers.
+                mFavoritePrinters = computeFavoritePrinters(printers);
+
+                // We want the first few favorite printers on top of the list.
+                final int favoriteCount = Math.min(mFavoritePrinters.size(),
+                        MAX_HISTORICAL_PRINTER_COUNT);
+                for (int i = 0; i < favoriteCount; i++) {
+                    PrinterInfo favoritePrinter = mFavoritePrinters.get(i);
+                    mPrinters.put(favoritePrinter.getId(), favoritePrinter);
+                }
+
+                mReadHistoryInProgress = false;
+                mReadHistoryCompleted = true;
+
+                loadInternal();
+            }
+
+            private List<PrinterInfo> doReadPrinterHistory() {
+                FileInputStream in = null;
+                try {
+                    in = mStatePersistFile.openRead();
+                } catch (FileNotFoundException fnfe) {
+                    Log.i(LOG_TAG, "No existing printer history.");
+                    return new ArrayList<PrinterInfo>();
+                }
+                try {
+                    List<PrinterInfo> printers = new ArrayList<PrinterInfo>();
+                    XmlPullParser parser = Xml.newPullParser();
+                    parser.setInput(in, null);
+                    parseState(parser, printers);
+                    return printers;
+                } 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 {
+                    IoUtils.closeQuietly(in);
+                }
+
+                return Collections.emptyList();
+            }
+
+            private void parseState(XmlPullParser parser, List<PrinterInfo> outPrinters)
+                    throws IOException, XmlPullParserException {
+                parser.next();
+                skipEmptyTextTags(parser);
+                expect(parser, XmlPullParser.START_TAG, TAG_PRINTERS);
+                parser.next();
+
+                while (parsePrinter(parser, outPrinters)) {
+                    // Be nice and respond to cancellation
+                    if (isCancelled()) {
+                        return;
+                    }
+                    parser.next();
+                }
+
+                skipEmptyTextTags(parser);
+                expect(parser, XmlPullParser.END_TAG, TAG_PRINTERS);
+            }
+
+            private boolean parsePrinter(XmlPullParser parser, List<PrinterInfo> outPrinters)
+                    throws IOException, XmlPullParserException {
+                skipEmptyTextTags(parser);
+                if (!accept(parser, XmlPullParser.START_TAG, TAG_PRINTER)) {
+                    return false;
+                }
+
+                String name = parser.getAttributeValue(null, ATTR_NAME);
+                String description = parser.getAttributeValue(null, ATTR_DESCRIPTION);
+                final int status = Integer.parseInt(parser.getAttributeValue(null, ATTR_STATUS));
+
+                parser.next();
+
+                skipEmptyTextTags(parser);
+                expect(parser, XmlPullParser.START_TAG, TAG_PRINTER_ID);
+                String localId = parser.getAttributeValue(null, ATTR_LOCAL_ID);
+                ComponentName service = ComponentName.unflattenFromString(parser.getAttributeValue(
+                        null, ATTR_SERVICE_NAME));
+                PrinterId printerId =  new PrinterId(service, localId);
+                parser.next();
+                skipEmptyTextTags(parser);
+                expect(parser, XmlPullParser.END_TAG, TAG_PRINTER_ID);
+                parser.next();
+
+                PrinterInfo.Builder builder = new PrinterInfo.Builder(printerId, name, status);
+                builder.setDescription(description);
+                PrinterInfo printer = builder.create();
+
+                outPrinters.add(printer);
+
+                if (DEBUG) {
+                    Log.i(LOG_TAG, "[RESTORED] " + printer);
+                }
+
+                skipEmptyTextTags(parser);
+                expect(parser, XmlPullParser.END_TAG, TAG_PRINTER);
+
+                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;
+            }
+        };
+
+        private final AsyncTask<List<PrinterInfo>, Void, Void> mWriteTask =
+                new AsyncTask<List<PrinterInfo>, Void, Void>() {
+            @Override
+            protected Void doInBackground(List<PrinterInfo>... printers) {
+                doWritePrinterHistory(printers[0]);
+                return null;
+            }
+
+            private void doWritePrinterHistory(List<PrinterInfo> printers) {
+                FileOutputStream out = null;
+                try {
+                    out = mStatePersistFile.startWrite();
+
+                    XmlSerializer serializer = new FastXmlSerializer();
+                    serializer.setOutput(out, "utf-8");
+                    serializer.startDocument(null, true);
+                    serializer.startTag(null, TAG_PRINTERS);
+
+                    final int printerCount = printers.size();
+                    for (int i = 0; i < printerCount; i++) {
+                        PrinterInfo printer = printers.get(i);
+
+                        serializer.startTag(null, TAG_PRINTER);
+
+                        serializer.attribute(null, ATTR_NAME, printer.getName());
+                        serializer.attribute(null, ATTR_STATUS, String.valueOf(
+                                printer.getStatus()));
+                        String description = printer.getDescription();
+                        if (description != null) {
+                            serializer.attribute(null, ATTR_DESCRIPTION, description);
+                        }
+
+                        PrinterId printerId = printer.getId();
+                        serializer.startTag(null, TAG_PRINTER_ID);
+                        serializer.attribute(null, ATTR_LOCAL_ID, printerId.getLocalId());
+                        serializer.attribute(null, ATTR_SERVICE_NAME, printerId.getServiceName()
+                                .flattenToString());
+                        serializer.endTag(null, TAG_PRINTER_ID);
+
+                        serializer.endTag(null, TAG_PRINTER);
+
+                        if (DEBUG) {
+                            Log.i(LOG_TAG, "[PERSISTED] " + printer);
+                        }
+                    }
+
+                    serializer.endTag(null, TAG_PRINTERS);
+                    serializer.endDocument();
+                    mStatePersistFile.finishWrite(out);
+
+                    if (DEBUG) {
+                        Log.i(LOG_TAG, "[PERSIST END]");
+                    }
+                } catch (IOException ioe) {
+                    Slog.w(LOG_TAG, "Failed to write printer history, restoring backup.", ioe);
+                    mStatePersistFile.failWrite(out);
+                } finally {
+                    IoUtils.closeQuietly(out);
+                }
+            }
+        };
+
+        private PersistenceManager(Context context) {
+            mStatePersistFile = new AtomicFile(new File(context.getFilesDir(),
+                    PERSIST_FILE_NAME));
+        }
+
+        public boolean isReadHistoryInProgress() {
+            return mReadHistoryInProgress;
+        }
+
+        public boolean isReadHistoryCompleted() {
+            return mReadHistoryCompleted;
+        }
+
+        public boolean stopReadPrinterHistory() {
+            return mReadTask.cancel(true);
+        }
+
+        public void readPrinterHistory() {
+            if (DEBUG) {
+                Log.i(LOG_TAG, "read history started");
+            }
+            mReadHistoryInProgress = true;
+            mReadTask.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, (Void[]) null);
+        }
+
+        @SuppressWarnings("unchecked")
+        public void addPrinterAndWritePrinterHistory(PrinterInfo printer) {
+            if (mHistoricalPrinters.size() >= MAX_HISTORY_LENGTH) {
+                mHistoricalPrinters.remove(0);
+            }
+            mHistoricalPrinters.add(printer);
+            mWriteTask.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, mHistoricalPrinters);
+        }
+
+        private List<PrinterInfo> computeFavoritePrinters(List<PrinterInfo> printers) {
+            Map<PrinterId, PrinterRecord> recordMap =
+                    new ArrayMap<PrinterId, PrinterRecord>();
+
+            // Recompute the weights.
+            float currentWeight = 1.0f;
+            final int printerCount = printers.size();
+            for (int i = printerCount - 1; i >= 0; i--) {
+                PrinterInfo printer = printers.get(i);
+                // Aggregate weight for the same printer
+                PrinterRecord record = recordMap.get(printer.getId());
+                if (record == null) {
+                    record = new PrinterRecord(printer);
+                    recordMap.put(printer.getId(), record);
+                }
+                record.weight += currentWeight;
+                currentWeight *= WEIGHT_DECAY_COEFFICIENT;
+            }
+
+            // Soft the favorite printers.
+            List<PrinterRecord> favoriteRecords = new ArrayList<PrinterRecord>(
+                    recordMap.values());
+            Collections.sort(favoriteRecords);
+
+            // Write the favorites to the output.
+            final int favoriteCount = favoriteRecords.size();
+            List<PrinterInfo> favoritePrinters = new ArrayList<PrinterInfo>(favoriteCount);
+            for (int i = 0; i < favoriteCount; i++) {
+                PrinterInfo printer = favoriteRecords.get(i).printer;
+                favoritePrinters.add(printer);
+            }
+
+            return favoritePrinters;
+        }
+
+        private final class PrinterRecord implements Comparable<PrinterRecord> {
+            public final PrinterInfo printer;
+            public float weight;
+
+            public PrinterRecord(PrinterInfo printer) {
+                this.printer = printer;
+            }
+
+            @Override
+            public int compareTo(PrinterRecord another) {
+                return Float.floatToIntBits(another.weight) - Float.floatToIntBits(weight);
+            }
+        }
+    }
+}