settings/search/Index.java

/*
 * Copyright (C) 2014 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.settings.search;

import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.database.Cursor;
import android.database.DatabaseUtils;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.os.AsyncTask;
import android.provider.SearchIndexableData;
import android.provider.SearchIndexableResource;
import android.provider.SearchIndexablesContract;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.util.Xml;
import com.android.settings.R;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.lang.reflect.Field;
import java.text.Normalizer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.regex.Pattern;

import static android.provider.SearchIndexablesContract.COLUMN_INDEX_NON_INDEXABLE_KEYS_KEY_VALUE;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_RANK;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_TITLE;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_SUMMARY_ON;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_SUMMARY_OFF;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_ENTRIES;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_KEYWORDS;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_SCREEN_TITLE;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_CLASS_NAME;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_ICON_RESID;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_INTENT_ACTION;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_INTENT_TARGET_PACKAGE;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_INTENT_TARGET_CLASS;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_RAW_KEY;

import static android.provider.SearchIndexablesContract.COLUMN_INDEX_XML_RES_RANK;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_XML_RES_RESID;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_XML_RES_CLASS_NAME;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_XML_RES_ICON_RESID;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_XML_RES_INTENT_ACTION;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_XML_RES_INTENT_TARGET_PACKAGE;
import static android.provider.SearchIndexablesContract.COLUMN_INDEX_XML_RES_INTENT_TARGET_CLASS;

import static com.android.settings.search.IndexDatabaseHelper.Tables;
import static com.android.settings.search.IndexDatabaseHelper.IndexColumns;

public class Index {

    private static final String LOG_TAG = "Index";

    // Those indices should match the indices of SELECT_COLUMNS !
    public static final int COLUMN_INDEX_RANK = 0;
    public static final int COLUMN_INDEX_TITLE = 1;
    public static final int COLUMN_INDEX_SUMMARY_ON = 2;
    public static final int COLUMN_INDEX_SUMMARY_OFF = 3;
    public static final int COLUMN_INDEX_ENTRIES = 4;
    public static final int COLUMN_INDEX_KEYWORDS = 5;
    public static final int COLUMN_INDEX_CLASS_NAME = 6;
    public static final int COLUMN_INDEX_SCREEN_TITLE = 7;
    public static final int COLUMN_INDEX_ICON = 8;
    public static final int COLUMN_INDEX_INTENT_ACTION = 9;
    public static final int COLUMN_INDEX_INTENT_ACTION_TARGET_PACKAGE = 10;
    public static final int COLUMN_INDEX_INTENT_ACTION_TARGET_CLASS = 11;
    public static final int COLUMN_INDEX_ENABLED = 12;
    public static final int COLUMN_INDEX_KEY = 13;

    public static final String ENTRIES_SEPARATOR = "|";

    // If you change the order of columns here, you SHOULD change the COLUMN_INDEX_XXX values
    private static final String[] SELECT_COLUMNS = new String[] {
            IndexColumns.DATA_RANK,               // 0
            IndexColumns.DATA_TITLE,              // 1
            IndexColumns.DATA_SUMMARY_ON,         // 2
            IndexColumns.DATA_SUMMARY_OFF,        // 3
            IndexColumns.DATA_ENTRIES,            // 4
            IndexColumns.DATA_KEYWORDS,           // 5
            IndexColumns.CLASS_NAME,              // 6
            IndexColumns.SCREEN_TITLE,            // 7
            IndexColumns.ICON,                    // 8
            IndexColumns.INTENT_ACTION,           // 9
            IndexColumns.INTENT_TARGET_PACKAGE,   // 10
            IndexColumns.INTENT_TARGET_CLASS,     // 11
            IndexColumns.ENABLED,                 // 12
            IndexColumns.DATA_KEY_REF             // 13
    };

    private static final String[] MATCH_COLUMNS = {
            IndexColumns.DATA_TITLE,
            IndexColumns.DATA_TITLE_NORMALIZED,
            IndexColumns.DATA_SUMMARY_ON,
            IndexColumns.DATA_SUMMARY_ON_NORMALIZED,
            IndexColumns.DATA_SUMMARY_OFF,
            IndexColumns.DATA_SUMMARY_OFF_NORMALIZED,
            IndexColumns.DATA_ENTRIES,
            IndexColumns.DATA_KEYWORDS
    };

    // Max number of saved search queries (who will be used for proposing suggestions)
    private static long MAX_SAVED_SEARCH_QUERY = 64;
    // Max number of proposed suggestions
    private static final int MAX_PROPOSED_SUGGESTIONS = 5;

    private static final String EMPTY = "";
    private static final String NON_BREAKING_HYPHEN = "\u2011";
    private static final String HYPHEN = "-";

    private static final String FIELD_NAME_SEARCH_INDEX_DATA_PROVIDER =
            "SEARCH_INDEX_DATA_PROVIDER";

    private static final String NODE_NAME_PREFERENCE_SCREEN = "PreferenceScreen";
    private static final String NODE_NAME_CHECK_BOX_PREFERENCE = "CheckBoxPreference";
    private static final String NODE_NAME_LIST_PREFERENCE = "ListPreference";

    private static final List<String> EMPTY_LIST = Collections.<String>emptyList();

    private static Index sInstance;

    private static final Pattern REMOVE_DIACRITICALS_PATTERN
            = Pattern.compile("\\p{InCombiningDiacriticalMarks}+");

    private final AtomicBoolean mIsAvailable = new AtomicBoolean(false);
    private final UpdateData mDataToProcess = new UpdateData();
    private Context mContext;

    /**
     * A private class to describe the update data for the Index database
     */
    private class UpdateData {
        public List<SearchIndexableData> dataToUpdate;
        public List<SearchIndexableData> dataToDelete;
        public Map<String, List<String>> nonIndexableKeys;

        public boolean forceUpdate = false;

        public UpdateData() {
            dataToUpdate = new ArrayList<SearchIndexableData>();
            dataToDelete = new ArrayList<SearchIndexableData>();
            nonIndexableKeys = new HashMap<String, List<String>>();
        }

        public void clear() {
            dataToUpdate.clear();
            dataToDelete.clear();
            nonIndexableKeys.clear();
            forceUpdate = false;
        }
    }

    /**
     * A basic singleton
     */
    public static Index getInstance(Context context) {
        if (sInstance == null) {
            sInstance = new Index(context);
        } else {
            sInstance.setContext(context);
        }
        return sInstance;
    }

    public Index(Context context) {
        mContext = context;
    }

    public void setContext(Context context) {
        mContext = context;
    }

    public boolean isAvailable() {
        return mIsAvailable.get();
    }

    public Cursor search(String query) {
        final String sql = buildSearchSQL(query);
        Log.d(LOG_TAG, "Search query: " + sql);
        return getReadableDatabase().rawQuery(sql, null);
    }

    public Cursor getSuggestions(String query) {
        final String sql = buildSuggestionsSQL(query);
        Log.d(LOG_TAG, "Suggestions query: " + sql);
        return getReadableDatabase().rawQuery(sql, null);
    }

    private String buildSuggestionsSQL(String query) {
        StringBuilder sb = new StringBuilder();

        sb.append("SELECT ");
        sb.append(IndexDatabaseHelper.SavedQueriesColums.QUERY);
        sb.append(" FROM ");
        sb.append(Tables.TABLE_SAVED_QUERIES);

        if (TextUtils.isEmpty(query)) {
            sb.append(" ORDER BY rowId DESC");
        } else {
            sb.append(" WHERE ");
            sb.append(IndexDatabaseHelper.SavedQueriesColums.QUERY);
            sb.append(" LIKE ");
            sb.append("'");
            sb.append(query);
            sb.append("%");
            sb.append("'");
        }

        sb.append(" LIMIT ");
        sb.append(MAX_PROPOSED_SUGGESTIONS);

        return sb.toString();
    }

    public long addSavedQuery(String query){
        final SaveSearchQueryTask task = new SaveSearchQueryTask();
        task.execute(query);
        try {
            return task.get();
        } catch (InterruptedException e) {
            Log.e(LOG_TAG, "Cannot insert saved query: " + query, e);
            return -1 ;
        } catch (ExecutionException e) {
            Log.e(LOG_TAG, "Cannot insert saved query: " + query, e);
            return -1;
        }
    }

    public boolean update() {
        final Intent intent = new Intent(SearchIndexablesContract.PROVIDER_INTERFACE);
        List<ResolveInfo> list =
                mContext.getPackageManager().queryIntentContentProviders(intent, 0);

        final int size = list.size();
        for (int n = 0; n < size; n++) {
            final ResolveInfo info = list.get(n);
            if (!isWellKnownProvider(info)) {
                continue;
            }
            final String authority = info.providerInfo.authority;
            final String packageName = info.providerInfo.packageName;

            addIndexablesFromRemoteProvider(packageName, authority);
            addNonIndexablesKeysFromRemoteProvider(packageName, authority);
        }

        return updateInternal();
    }

    private boolean addIndexablesFromRemoteProvider(String packageName, String authority) {
        try {
            final Context packageContext = mContext.createPackageContext(packageName, 0);

            final Uri uriForResources = buildUriForXmlResources(authority);
            addIndexablesForXmlResourceUri(packageContext, packageName, uriForResources,
                    SearchIndexablesContract.INDEXABLES_XML_RES_COLUMNS);

            final Uri uriForRawData = buildUriForRawData(authority);
            addIndexablesForRawDataUri(packageContext, packageName, uriForRawData,
                    SearchIndexablesContract.INDEXABLES_RAW_COLUMNS);
            return true;
        } catch (PackageManager.NameNotFoundException e) {
            Log.w(LOG_TAG, "Could not create context for " + packageName + ": "
                    + Log.getStackTraceString(e));
            return false;
        }
    }

    private void addNonIndexablesKeysFromRemoteProvider(String packageName,
                                                        String authority) {
        final List<String> keys =
                getNonIndexablesKeysFromRemoteProvider(packageName, authority);
        addNonIndexableKeys(packageName, keys);
    }

    private List<String> getNonIndexablesKeysFromRemoteProvider(String packageName,
                                                                String authority) {
        try {
            final Context packageContext = mContext.createPackageContext(packageName, 0);

            final Uri uriForNonIndexableKeys = buildUriForNonIndexableKeys(authority);
            return getNonIndexablesKeys(packageContext, uriForNonIndexableKeys,
                    SearchIndexablesContract.NON_INDEXABLES_KEYS_COLUMNS);
        } catch (PackageManager.NameNotFoundException e) {
            Log.w(LOG_TAG, "Could not create context for " + packageName + ": "
                    + Log.getStackTraceString(e));
            return EMPTY_LIST;
        }
    }

    private List<String> getNonIndexablesKeys(Context packageContext, Uri uri,
                                              String[] projection) {

        final ContentResolver resolver = packageContext.getContentResolver();
        final Cursor cursor = resolver.query(uri, projection, null, null, null);

        if (cursor == null) {
            Log.w(LOG_TAG, "Cannot add index data for Uri: " + uri.toString());
            return EMPTY_LIST;
        }

        List<String> result = new ArrayList<String>();
        try {
            final int count = cursor.getCount();
            if (count > 0) {
                while (cursor.moveToNext()) {
                    final String key = cursor.getString(COLUMN_INDEX_NON_INDEXABLE_KEYS_KEY_VALUE);
                    result.add(key);
                }
            }
            return result;
        } finally {
            cursor.close();
        }
    }

    public void addIndexableData(SearchIndexableData data) {
        synchronized (mDataToProcess) {
            mDataToProcess.dataToUpdate.add(data);
        }
    }

    public void addIndexableData(SearchIndexableResource[] array) {
        synchronized (mDataToProcess) {
            final int count = array.length;
            for (int n = 0; n < count; n++) {
                mDataToProcess.dataToUpdate.add(array[n]);
            }
        }
    }

    public void deleteIndexableData(SearchIndexableData data) {
        synchronized (mDataToProcess) {
            mDataToProcess.dataToDelete.add(data);
        }
    }

    public void addNonIndexableKeys(String authority, List<String> keys) {
        synchronized (mDataToProcess) {
            mDataToProcess.nonIndexableKeys.put(authority, keys);
        }
    }

    /**
     * Only allow a "well known" SearchIndexablesProvider. The provider should:
     *
     * - have read/write {@link android.Manifest.permission#READ_SEARCH_INDEXABLES}
     * - be from a privileged package
     */
    private boolean isWellKnownProvider(ResolveInfo info) {
        final String authority = info.providerInfo.authority;
        final String packageName = info.providerInfo.applicationInfo.packageName;

        if (TextUtils.isEmpty(authority) || TextUtils.isEmpty(packageName)) {
            return false;
        }

        final String readPermission = info.providerInfo.readPermission;
        final String writePermission = info.providerInfo.writePermission;

        if (TextUtils.isEmpty(readPermission) || TextUtils.isEmpty(writePermission)) {
            return false;
        }

        if (!android.Manifest.permission.READ_SEARCH_INDEXABLES.equals(readPermission) ||
            !android.Manifest.permission.READ_SEARCH_INDEXABLES.equals(writePermission)) {
            return false;
        }

        return isPrivilegedPackage(packageName);
    }

    private boolean isPrivilegedPackage(String packageName) {
        final PackageManager pm = mContext.getPackageManager();
        try {
            PackageInfo packInfo = pm.getPackageInfo(packageName, 0);
            return ((packInfo.applicationInfo.flags & ApplicationInfo.FLAG_PRIVILEGED) != 0);
        } catch (PackageManager.NameNotFoundException e) {
            return false;
        }
    }

    public boolean updateFromRemoteProvider(String packageName, String authority) {
        if (!addIndexablesFromRemoteProvider(packageName, authority)) {
            return false;
        }
        return updateInternal();
    }

    /**
     * Update the Index for a specific class name resources
     *
     * @param className the class name (typically a fragment name).
     * @param rebuild true means that you want to delete the data from the Index first.
     * @param includeInSearchResults true means that you want the bit "enabled" set so that the
     *                               data will be seen included into the search results
     * @return true of the Index update has been successful.
     */
    public boolean updateFromClassNameResource(String className, boolean rebuild,
            boolean includeInSearchResults) {
        if (className == null) {
            throw new IllegalArgumentException("class name cannot be null!");
        }
        final SearchIndexableResource res = SearchIndexableResources.getResourceByName(className);
        if (res == null ) {
            Log.e(LOG_TAG, "Cannot find SearchIndexableResources for class name: " + className);
            return false;
        }
        res.context = mContext;
        res.enabled = includeInSearchResults;
        if (rebuild) {
            deleteIndexableData(res);
        }
        addIndexableData(res);
        mDataToProcess.forceUpdate = true;
        boolean result = updateInternal();
        res.enabled = false;
        return result;
    }

    public boolean updateFromSearchIndexableData(SearchIndexableData data) {
        addIndexableData(data);
        mDataToProcess.forceUpdate = true;
        return updateInternal();
    }

    private SQLiteDatabase getReadableDatabase() {
        return IndexDatabaseHelper.getInstance(mContext).getReadableDatabase();
    }

    private SQLiteDatabase getWritableDatabase() {
        return IndexDatabaseHelper.getInstance(mContext).getWritableDatabase();
    }

    private static Uri buildUriForXmlResources(String authority) {
        return Uri.parse("content://" + authority + "/" +
                SearchIndexablesContract.INDEXABLES_XML_RES_PATH);
    }

    private static Uri buildUriForRawData(String authority) {
        return Uri.parse("content://" + authority + "/" +
                SearchIndexablesContract.INDEXABLES_RAW_PATH);
    }

    private static Uri buildUriForNonIndexableKeys(String authority) {
        return Uri.parse("content://" + authority + "/" +
                SearchIndexablesContract.NON_INDEXABLES_KEYS_PATH);
    }

    private boolean updateInternal() {
        synchronized (mDataToProcess) {
            final UpdateIndexTask task = new UpdateIndexTask();
            task.execute(mDataToProcess);
            try {
                final boolean result = task.get();
                mDataToProcess.clear();
                return result;
            } catch (InterruptedException e) {
                Log.e(LOG_TAG, "Cannot update index", e);
                return false;
            } catch (ExecutionException e) {
                Log.e(LOG_TAG, "Cannot update index", e);
                return false;
            }
        }
    }

    private void addIndexablesForXmlResourceUri(Context packageContext, String packageName,
            Uri uri, String[] projection) {

        final ContentResolver resolver = packageContext.getContentResolver();
        final Cursor cursor = resolver.query(uri, projection, null, null, null);

        if (cursor == null) {
            Log.w(LOG_TAG, "Cannot add index data for Uri: " + uri.toString());
            return;
        }

        try {
            final int count = cursor.getCount();
            if (count > 0) {
                while (cursor.moveToNext()) {
                    final int rank = cursor.getInt(COLUMN_INDEX_XML_RES_RANK);
                    final int xmlResId = cursor.getInt(COLUMN_INDEX_XML_RES_RESID);

                    final String className = cursor.getString(COLUMN_INDEX_XML_RES_CLASS_NAME);
                    final int iconResId = cursor.getInt(COLUMN_INDEX_XML_RES_ICON_RESID);

                    final String action = cursor.getString(COLUMN_INDEX_XML_RES_INTENT_ACTION);
                    final String targetPackage = cursor.getString(
                            COLUMN_INDEX_XML_RES_INTENT_TARGET_PACKAGE);
                    final String targetClass = cursor.getString(
                            COLUMN_INDEX_XML_RES_INTENT_TARGET_CLASS);

                    SearchIndexableResource sir = new SearchIndexableResource(packageContext);
                    sir.rank = rank;
                    sir.xmlResId = xmlResId;
                    sir.className = className;
                    sir.packageName = packageName;
                    sir.iconResId = iconResId;
                    sir.intentAction = action;
                    sir.intentTargetPackage = targetPackage;
                    sir.intentTargetClass = targetClass;

                    addIndexableData(sir);
                }
            }
        } finally {
            cursor.close();
        }
    }

    private void addIndexablesForRawDataUri(Context packageContext, String packageName,
            Uri uri, String[] projection) {

        final ContentResolver resolver = packageContext.getContentResolver();
        final Cursor cursor = resolver.query(uri, projection, null, null, null);

        if (cursor == null) {
            Log.w(LOG_TAG, "Cannot add index data for Uri: " + uri.toString());
            return;
        }

        try {
            final int count = cursor.getCount();
            if (count > 0) {
                while (cursor.moveToNext()) {
                    final int rank = cursor.getInt(COLUMN_INDEX_RAW_RANK);
                    final String title = cursor.getString(COLUMN_INDEX_RAW_TITLE);
                    final String summaryOn = cursor.getString(COLUMN_INDEX_RAW_SUMMARY_ON);
                    final String summaryOff = cursor.getString(COLUMN_INDEX_RAW_SUMMARY_OFF);
                    final String entries = cursor.getString(COLUMN_INDEX_RAW_ENTRIES);
                    final String keywords = cursor.getString(COLUMN_INDEX_RAW_KEYWORDS);

                    final String screenTitle = cursor.getString(COLUMN_INDEX_RAW_SCREEN_TITLE);

                    final String className = cursor.getString(COLUMN_INDEX_RAW_CLASS_NAME);
                    final int iconResId = cursor.getInt(COLUMN_INDEX_RAW_ICON_RESID);

                    final String action = cursor.getString(COLUMN_INDEX_RAW_INTENT_ACTION);
                    final String targetPackage = cursor.getString(
                            COLUMN_INDEX_RAW_INTENT_TARGET_PACKAGE);
                    final String targetClass = cursor.getString(
                            COLUMN_INDEX_RAW_INTENT_TARGET_CLASS);

                    final String key = cursor.getString(COLUMN_INDEX_RAW_KEY);

                    SearchIndexableRaw data = new SearchIndexableRaw(packageContext);
                    data.rank = rank;
                    data.title = title;
                    data.summaryOn = summaryOn;
                    data.summaryOff = summaryOff;
                    data.entries = entries;
                    data.keywords = keywords;
                    data.screenTitle = screenTitle;
                    data.className = className;
                    data.packageName = packageName;
                    data.iconResId = iconResId;
                    data.intentAction = action;
                    data.intentTargetPackage = targetPackage;
                    data.intentTargetClass = targetClass;
                    data.key = key;

                    addIndexableData(data);
                }
            }
        } finally {
            cursor.close();
        }
    }

    private String buildSearchSQL(String query) {
        StringBuilder sb = new StringBuilder();
        sb.append(buildSearchSQLForColumn(query, MATCH_COLUMNS));
        sb.append(" ORDER BY ");
        sb.append(IndexColumns.DATA_RANK);
        return sb.toString();
    }

    private String buildSearchSQLForColumn(String query, String[] columnNames) {
        StringBuilder sb = new StringBuilder();
        sb.append("SELECT ");
        for (int n = 0; n < SELECT_COLUMNS.length; n++) {
            sb.append(SELECT_COLUMNS[n]);
            if (n < SELECT_COLUMNS.length - 1) {
                sb.append(", ");
            }
        }
        sb.append(" FROM ");
        sb.append(Tables.TABLE_PREFS_INDEX);
        sb.append(" WHERE ");
        sb.append(buildSearchWhereStringForColumns(query, columnNames));

        return sb.toString();
    }

    private String buildSearchWhereStringForColumns(String query, String[] columnNames) {
        final StringBuilder sb = new StringBuilder(Tables.TABLE_PREFS_INDEX);
        sb.append(" MATCH ");
        DatabaseUtils.appendEscapedSQLString(sb,
                buildSearchMatchStringForColumns(query, columnNames));
        sb.append(" AND ");
        sb.append(IndexColumns.LOCALE);
        sb.append(" = ");
        DatabaseUtils.appendEscapedSQLString(sb, Locale.getDefault().toString());
        sb.append(" AND ");
        sb.append(IndexColumns.ENABLED);
        sb.append(" = 1");
        return sb.toString();
    }

    private String buildSearchMatchStringForColumns(String query, String[] columnNames) {
        final String value = query + "*";
        StringBuilder sb = new StringBuilder();
        final int count = columnNames.length;
        for (int n = 0; n < count; n++) {
            sb.append(columnNames[n]);
            sb.append(":");
            sb.append(value);
            if (n < count - 1) {
                sb.append(" OR ");
            }
        }
        return sb.toString();
    }

    private void indexOneSearchIndexableData(SQLiteDatabase database, String localeStr,
            SearchIndexableData data, Map<String, List<String>> nonIndexableKeys) {
        if (data instanceof SearchIndexableResource) {
            indexOneResource(database, localeStr, (SearchIndexableResource) data, nonIndexableKeys);
        } else if (data instanceof SearchIndexableRaw) {
            indexOneRaw(database, localeStr, (SearchIndexableRaw) data);
        }
    }

    private void indexOneRaw(SQLiteDatabase database, String localeStr,
                             SearchIndexableRaw raw) {
        // Should be the same locale as the one we are processing
        if (!raw.locale.toString().equalsIgnoreCase(localeStr)) {
            return;
        }

        updateOneRowWithFilteredData(database, localeStr,
                raw.title,
                raw.summaryOn,
                raw.summaryOff,
                raw.entries,
                raw.className,
                raw.screenTitle,
                raw.iconResId,
                raw.rank,
                raw.keywords,
                raw.intentAction,
                raw.intentTargetPackage,
                raw.intentTargetClass,
                raw.enabled,
                raw.key);
    }

    private void indexOneResource(SQLiteDatabase database, String localeStr,
            SearchIndexableResource sir, Map<String, List<String>> nonIndexableKeysFromResource) {

        if (sir == null) {
            Log.e(LOG_TAG, "Cannot index a null resource!");
            return;
        }

        // Will be non null only for a Local provider
        final Indexable.SearchIndexProvider provider =
                TextUtils.isEmpty(sir.className) ? null : getSearchIndexProvider(sir.className);

        List<String> nonIndexableKeys = new ArrayList<String>();

        if (sir.xmlResId > SearchIndexableResources.NO_DATA_RES_ID) {
            List<String> resNonIndxableKeys = nonIndexableKeysFromResource.get(sir.packageName);
            if (resNonIndxableKeys != null && resNonIndxableKeys.size() > 0) {
                nonIndexableKeys.addAll(resNonIndxableKeys);
            }
            indexFromResource(sir.context, database, localeStr,
                    sir.xmlResId, sir.className, sir.iconResId, sir.rank,
                    sir.intentAction, sir.intentTargetPackage, sir.intentTargetClass,
                    nonIndexableKeys);
        } else if (!TextUtils.isEmpty(sir.className)) {
            if (provider != null) {
                List<String> providerNonIndexableKeys = provider.getNonIndexableKeys(sir.context);
                if (providerNonIndexableKeys != null && providerNonIndexableKeys.size() > 0) {
                    nonIndexableKeys.addAll(providerNonIndexableKeys);
                }
            }
            indexFromLocalProvider(mContext, database, localeStr, provider, sir.className,
                    sir.iconResId, sir.rank, sir.enabled, nonIndexableKeys);
        }
    }

    private Indexable.SearchIndexProvider getSearchIndexProvider(String className) {
        try {
            final Class<?> clazz = Class.forName(className);
            if (Indexable.class.isAssignableFrom(clazz)) {
                final Field f = clazz.getField(FIELD_NAME_SEARCH_INDEX_DATA_PROVIDER);
                return (Indexable.SearchIndexProvider) f.get(null);
            }
        } catch (ClassNotFoundException e) {
            Log.e(LOG_TAG, "Cannot find class: " + className, e);
        } catch (NoSuchFieldException e) {
            Log.e(LOG_TAG, "Cannot find field '" + FIELD_NAME_SEARCH_INDEX_DATA_PROVIDER + "'", e);
        } catch (IllegalAccessException e) {
            Log.e(LOG_TAG,
                    "Illegal access to field '" + FIELD_NAME_SEARCH_INDEX_DATA_PROVIDER + "'", e);
        }
        return null;
    }

    private void indexFromResource(Context context, SQLiteDatabase database, String localeStr,
           int xmlResId, String fragmentName, int iconResId, int rank,
           String intentAction, String intentTargetPackage, String intentTargetClass,
           List<String> nonIndexableKeys) {

        XmlResourceParser parser = null;
        try {
            parser = context.getResources().getXml(xmlResId);

            int type;
            while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
                    && type != XmlPullParser.START_TAG) {
                // Parse next until start tag is found
            }

            String nodeName = parser.getName();
            if (!NODE_NAME_PREFERENCE_SCREEN.equals(nodeName)) {
                throw new RuntimeException(
                        "XML document must start with <PreferenceScreen> tag; found"
                                + nodeName + " at " + parser.getPositionDescription());
            }

            final int outerDepth = parser.getDepth();
            final AttributeSet attrs = Xml.asAttributeSet(parser);

            final String screenTitle = getDataTitle(context, attrs);

            String key = getDataKey(context, attrs);

            String title;
            String summary;
            String keywords;

            // Insert rows for the main PreferenceScreen node. Rewrite the data for removing
            // hyphens.
            if (!nonIndexableKeys.contains(key)) {
                title = getDataTitle(context, attrs);
                summary = getDataSummary(context, attrs);
                keywords = getDataKeywords(context, attrs);

                updateOneRowWithFilteredData(database, localeStr, title, summary, null, null,
                        fragmentName, screenTitle, iconResId, rank,
                        keywords, intentAction, intentTargetPackage, intentTargetClass, true, key);
            }

            while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
                    && (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {
                if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT) {
                    continue;
                }

                nodeName = parser.getName();

                key = getDataKey(context, attrs);
                if (nonIndexableKeys.contains(key)) {
                    continue;
                }

                title = getDataTitle(context, attrs);
                keywords = getDataKeywords(context, attrs);

                if (!nodeName.equals(NODE_NAME_CHECK_BOX_PREFERENCE)) {
                    summary = getDataSummary(context, attrs);

                    String entries = null;

                    if (nodeName.endsWith(NODE_NAME_LIST_PREFERENCE)) {
                        entries = getDataEntries(context, attrs);
                    }

                    // Insert rows for the child nodes of PreferenceScreen
                    updateOneRowWithFilteredData(database, localeStr, title, summary, null, entries,
                            fragmentName, screenTitle, iconResId, rank,
                            keywords, intentAction, intentTargetPackage, intentTargetClass,
                            true, key);
                } else {
                    String summaryOn = getDataSummaryOn(context, attrs);
                    String summaryOff = getDataSummaryOff(context, attrs);

                    if (TextUtils.isEmpty(summaryOn) && TextUtils.isEmpty(summaryOff)) {
                        summaryOn = getDataSummary(context, attrs);
                    }

                    updateOneRowWithFilteredData(database, localeStr, title, summaryOn, summaryOff,
                            null, fragmentName, screenTitle, iconResId, rank,
                            keywords, intentAction, intentTargetPackage, intentTargetClass,
                            true, key);
                }
            }

        } catch (XmlPullParserException e) {
            throw new RuntimeException("Error parsing PreferenceScreen", e);
        } catch (IOException e) {
            throw new RuntimeException("Error parsing PreferenceScreen", e);
        } finally {
            if (parser != null) parser.close();
        }
    }

    private void indexFromLocalProvider(Context context, SQLiteDatabase database, String localeStr,
            Indexable.SearchIndexProvider provider, String className, int iconResId, int rank,
            boolean enabled, List<String> nonIndexableKeys) {

        if (provider == null) {
            Log.w(LOG_TAG, "Cannot find provider: " + className);
            return;
        }

        final List<SearchIndexableRaw> rawList = provider.getRawDataToIndex(context, enabled);

        if (rawList != null) {
            final int rawSize = rawList.size();
            for (int i = 0; i < rawSize; i++) {
                SearchIndexableRaw raw = rawList.get(i);

                // Should be the same locale as the one we are processing
                if (!raw.locale.toString().equalsIgnoreCase(localeStr)) {
                    continue;
                }

                if (nonIndexableKeys.contains(raw.key)) {
                    continue;
                }

                updateOneRowWithFilteredData(database, localeStr,
                        raw.title,
                        raw.summaryOn,
                        raw.summaryOff,
                        raw.entries,
                        className,
                        raw.screenTitle,
                        iconResId,
                        rank,
                        raw.keywords,
                        raw.intentAction,
                        raw.intentTargetPackage,
                        raw.intentTargetClass,
                        raw.enabled,
                        raw.key);
            }
        }

        final List<SearchIndexableResource> resList =
                provider.getXmlResourcesToIndex(context, enabled);
        if (resList != null) {
            final int resSize = resList.size();
            for (int i = 0; i < resSize; i++) {
                SearchIndexableResource item = resList.get(i);

                // Should be the same locale as the one we are processing
                if (!item.locale.toString().equalsIgnoreCase(localeStr)) {
                    continue;
                }

                final int itemIconResId = (item.iconResId == 0) ? iconResId : item.iconResId;
                final int itemRank = (item.rank == 0) ? rank : item.rank;
                String itemClassName = (TextUtils.isEmpty(item.className))
                        ? className : item.className;

                indexFromResource(context, database, localeStr,
                        item.xmlResId, itemClassName, itemIconResId, itemRank,
                        item.intentAction, item.intentTargetPackage,
                        item.intentTargetClass, nonIndexableKeys);
            }
        }
    }

    private void updateOneRowWithFilteredData(SQLiteDatabase database, String locale,
            String title, String summaryOn, String summaryOff, String entries,
            String className,
            String screenTitle, int iconResId, int rank, String keywords,
            String intentAction, String intentTargetPackage, String intentTargetClass,
            boolean enabled, String key) {

        final String updatedTitle = normalizeHyphen(title);
        final String updatedSummaryOn = normalizeHyphen(summaryOn);
        final String updatedSummaryOff = normalizeHyphen(summaryOff);

        final String normalizedTitle = normalizeString(updatedTitle);
        final String normalizedSummaryOn = normalizeString(updatedSummaryOn);
        final String normalizedSummaryOff = normalizeString(updatedSummaryOff);

        updateOneRow(database, locale,
                updatedTitle, normalizedTitle, updatedSummaryOn, normalizedSummaryOn,
                updatedSummaryOff, normalizedSummaryOff, entries,
                className, screenTitle, iconResId,
                rank, keywords, intentAction, intentTargetPackage, intentTargetClass, enabled, key);
    }

    private static String normalizeHyphen(String input) {
        return (input != null) ? input.replaceAll(NON_BREAKING_HYPHEN, HYPHEN) : EMPTY;
    }

    private static String normalizeString(String input) {
        final String nohyphen = (input != null) ? input.replaceAll(HYPHEN, EMPTY) : EMPTY;
        final String normalized = Normalizer.normalize(nohyphen, Normalizer.Form.NFD);

        return REMOVE_DIACRITICALS_PATTERN.matcher(normalized).replaceAll("").toLowerCase();
    }

    private void updateOneRow(SQLiteDatabase database, String locale,
            String updatedTitle, String normalizedTitle,
            String updatedSummaryOn, String normalizedSummaryOn,
            String updatedSummaryOff, String normalizedSummaryOff, String entries,
            String className, String screenTitle, int iconResId, int rank, String keywords,
            String intentAction, String intentTargetPackage, String intentTargetClass,
            boolean enabled, String key) {

        if (TextUtils.isEmpty(updatedTitle)) {
            return;
        }

        ContentValues values = new ContentValues();
        values.put(IndexColumns.DOCID, updatedTitle.hashCode());
        values.put(IndexColumns.LOCALE, locale);
        values.put(IndexColumns.DATA_RANK, rank);
        values.put(IndexColumns.DATA_TITLE, updatedTitle);
        values.put(IndexColumns.DATA_TITLE_NORMALIZED, normalizedTitle);
        values.put(IndexColumns.DATA_SUMMARY_ON, updatedSummaryOn);
        values.put(IndexColumns.DATA_SUMMARY_ON_NORMALIZED, normalizedSummaryOn);
        values.put(IndexColumns.DATA_SUMMARY_OFF, updatedSummaryOff);
        values.put(IndexColumns.DATA_SUMMARY_OFF_NORMALIZED, normalizedSummaryOff);
        values.put(IndexColumns.DATA_ENTRIES, entries);
        values.put(IndexColumns.DATA_KEYWORDS, keywords);
        values.put(IndexColumns.CLASS_NAME, className);
        values.put(IndexColumns.SCREEN_TITLE, screenTitle);
        values.put(IndexColumns.INTENT_ACTION, intentAction);
        values.put(IndexColumns.INTENT_TARGET_PACKAGE, intentTargetPackage);
        values.put(IndexColumns.INTENT_TARGET_CLASS, intentTargetClass);
        values.put(IndexColumns.ICON, iconResId);
        values.put(IndexColumns.ENABLED, enabled);
        values.put(IndexColumns.DATA_KEY_REF, key);

        database.replaceOrThrow(Tables.TABLE_PREFS_INDEX, null, values);
    }

    private String getDataKey(Context context, AttributeSet attrs) {
        return getData(context, attrs,
                com.android.internal.R.styleable.Preference,
                com.android.internal.R.styleable.Preference_key);
    }

    private String getDataTitle(Context context, AttributeSet attrs) {
        return getData(context, attrs,
                com.android.internal.R.styleable.Preference,
                com.android.internal.R.styleable.Preference_title);
    }

    private String getDataSummary(Context context, AttributeSet attrs) {
        return getData(context, attrs,
                com.android.internal.R.styleable.Preference,
                com.android.internal.R.styleable.Preference_summary);
    }

    private String getDataSummaryOn(Context context, AttributeSet attrs) {
        return getData(context, attrs,
                com.android.internal.R.styleable.CheckBoxPreference,
                com.android.internal.R.styleable.CheckBoxPreference_summaryOn);
    }

    private String getDataSummaryOff(Context context, AttributeSet attrs) {
        return getData(context, attrs,
                com.android.internal.R.styleable.CheckBoxPreference,
                com.android.internal.R.styleable.CheckBoxPreference_summaryOff);
    }

    private String getDataEntries(Context context, AttributeSet attrs) {
        return getDataEntries(context, attrs,
                com.android.internal.R.styleable.ListPreference,
                com.android.internal.R.styleable.ListPreference_entries);
    }

    private String getDataKeywords(Context context, AttributeSet attrs) {
        return getData(context, attrs, R.styleable.Preference, R.styleable.Preference_keywords);
    }

    private String getData(Context context, AttributeSet set, int[] attrs, int resId) {
        final TypedArray sa = context.obtainStyledAttributes(set, attrs);
        final TypedValue tv = sa.peekValue(resId);

        CharSequence data = null;
        if (tv != null && tv.type == TypedValue.TYPE_STRING) {
            if (tv.resourceId != 0) {
                data = context.getText(tv.resourceId);
            } else {
                data = tv.string;
            }
        }
        return (data != null) ? data.toString() : null;
    }

    private String getDataEntries(Context context, AttributeSet set, int[] attrs, int resId) {
        final TypedArray sa = context.obtainStyledAttributes(set, attrs);
        final TypedValue tv = sa.peekValue(resId);

        String[] data = null;
        if (tv != null && tv.type == TypedValue.TYPE_REFERENCE) {
            if (tv.resourceId != 0) {
                data = context.getResources().getStringArray(tv.resourceId);
            }
        }
        final int count = (data == null ) ? 0 : data.length;
        if (count == 0) {
            return null;
        }
        final StringBuilder result = new StringBuilder();
        for (int n = 0; n < count; n++) {
            result.append(data[n]);
            result.append(ENTRIES_SEPARATOR);
        }
        return result.toString();
    }

    private int getResId(Context context, AttributeSet set, int[] attrs, int resId) {
        final TypedArray sa = context.obtainStyledAttributes(set, attrs);
        final TypedValue tv = sa.peekValue(resId);

        if (tv != null && tv.type == TypedValue.TYPE_STRING) {
            return tv.resourceId;
        } else {
            return 0;
        }
   }

    /**
     * A private class for updating the Index database
     */
    private class UpdateIndexTask extends AsyncTask<UpdateData, Integer, Boolean> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            mIsAvailable.set(false);
        }

        @Override
        protected void onPostExecute(Boolean aBoolean) {
            super.onPostExecute(aBoolean);
            mIsAvailable.set(true);
        }

        @Override
        protected Boolean doInBackground(UpdateData... params) {
            boolean result = false;

            final List<SearchIndexableData> dataToUpdate = params[0].dataToUpdate;
            final List<SearchIndexableData> dataToDelete = params[0].dataToDelete;
            final Map<String, List<String>> nonIndexableKeys = params[0].nonIndexableKeys;

            final boolean forceUpdate = params[0].forceUpdate;

            final SQLiteDatabase database = getWritableDatabase();
            final String localeStr = Locale.getDefault().toString();

            try {
                database.beginTransaction();
                if (dataToDelete.size() > 0) {
                    processDataToDelete(database, localeStr, dataToDelete);
                }
                if (dataToUpdate.size() > 0) {
                    processDataToUpdate(database, localeStr, dataToUpdate, nonIndexableKeys,
                            forceUpdate);
                }
                database.setTransactionSuccessful();
                result = true;
            } finally {
                database.endTransaction();
            }
            return result;
        }

        private boolean processDataToUpdate(SQLiteDatabase database, String localeStr,
                List<SearchIndexableData> dataToUpdate, Map<String, List<String>> nonIndexableKeys,
                boolean forceUpdate) {

            if (!forceUpdate && isLocaleAlreadyIndexed(database, localeStr)) {
                Log.d(LOG_TAG, "Locale '" + localeStr + "' is already indexed");
                return true;
            }

            boolean result = false;
            final long current = System.currentTimeMillis();

            final int count = dataToUpdate.size();
            for (int n = 0; n < count; n++) {
                final SearchIndexableData data = dataToUpdate.get(n);
                indexOneSearchIndexableData(database, localeStr, data, nonIndexableKeys);
            }

            final long now = System.currentTimeMillis();
            Log.d(LOG_TAG, "Indexing locale '" + localeStr + "' took " +
                    (now - current) + " millis");
            return result;
        }

        private boolean processDataToDelete(SQLiteDatabase database, String localeStr,
                List<SearchIndexableData> dataToDelete) {

            boolean result = false;
            final long current = System.currentTimeMillis();

            final int count = dataToDelete.size();
            for (int n = 0; n < count; n++) {
                final SearchIndexableData data = dataToDelete.get(n);
                if (data == null) {
                    continue;
                }
                if (!TextUtils.isEmpty(data.className)) {
                    delete(database, IndexColumns.CLASS_NAME, data.className);
                } else  {
                    if (data instanceof SearchIndexableRaw) {
                        final SearchIndexableRaw raw = (SearchIndexableRaw) data;
                        if (!TextUtils.isEmpty(raw.title)) {
                            delete(database, IndexColumns.DATA_TITLE, raw.title);
                        }
                    }
                }
            }

            final long now = System.currentTimeMillis();
            Log.d(LOG_TAG, "Deleting data for locale '" + localeStr + "' took " +
                    (now - current) + " millis");
            return result;
        }

        private int delete(SQLiteDatabase database, String columName, String value) {
            final String whereClause = columName + "=?";
            final String[] whereArgs = new String[] { value };

            return database.delete(Tables.TABLE_PREFS_INDEX, whereClause, whereArgs);
        }

        private boolean isLocaleAlreadyIndexed(SQLiteDatabase database, String locale) {
            Cursor cursor = null;
            boolean result = false;
            final StringBuilder sb = new StringBuilder(IndexColumns.LOCALE);
            sb.append(" = ");
            DatabaseUtils.appendEscapedSQLString(sb, locale);
            try {
                // We care only for 1 row
                cursor = database.query(Tables.TABLE_PREFS_INDEX, null,
                        sb.toString(), null, null, null, null, "1");
                final int count = cursor.getCount();
                result = (count >= 1);
            } finally {
                if (cursor != null) {
                    cursor.close();
                }
            }
            return result;
        }
    }

    /**
     * A basic AsynTask for saving a Search query into the database
     */
    private class SaveSearchQueryTask extends AsyncTask<String, Void, Long> {

        @Override
        protected Long doInBackground(String... params) {
            final long now = new Date().getTime();

            final ContentValues values = new ContentValues();
            values.put(IndexDatabaseHelper.SavedQueriesColums.QUERY, params[0]);
            values.put(IndexDatabaseHelper.SavedQueriesColums.TIME_STAMP, now);

            final SQLiteDatabase database = getWritableDatabase();

            long lastInsertedRowId = -1;
            try {
                // First, delete all saved queries that are the same
                database.delete(Tables.TABLE_SAVED_QUERIES,
                        IndexDatabaseHelper.SavedQueriesColums.QUERY + " = ?",
                        new String[] { params[0] });

                // Second, insert the saved query
                lastInsertedRowId =
                        database.insertOrThrow(Tables.TABLE_SAVED_QUERIES, null, values);

                // Last, remove "old" saved queries
                final long delta = lastInsertedRowId - MAX_SAVED_SEARCH_QUERY;
                if (delta > 0) {
                    int count = database.delete(Tables.TABLE_SAVED_QUERIES, "rowId <= ?",
                            new String[] { Long.toString(delta) });
                    Log.d(LOG_TAG, "Deleted '" + count + "' saved Search query(ies)");
                }
            } catch (Exception e) {
                Log.d(LOG_TAG, "Cannot update saved Search queries", e);
            }

            return lastInsertedRowId;
        }
    }
}