The Tor Browser: mobile/android/base/db/BrowserProvider.java@fc2d59ddac77 (annotated)

mobile/android/base/db/BrowserProvider.java@fc2d59ddac77 (annotated)

mobile/android/base/db/BrowserProvider.java

Wed, 31 Dec 2014 07:22:50 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 07:22:50 +0100
branch: TOR_BUG_3246
changeset 4: fc2d59ddac77
permissions: -rw-r--r--

Correct previous dual key logic pending first delivery installment.

 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 package org.mozilla.gecko.db;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import org.mozilla.gecko.db.BrowserContract.Bookmarks;
 import org.mozilla.gecko.db.BrowserContract.Combined;
 import org.mozilla.gecko.db.BrowserContract.CommonColumns;
 import org.mozilla.gecko.db.BrowserContract.FaviconColumns;
 import org.mozilla.gecko.db.BrowserContract.Favicons;
 import org.mozilla.gecko.db.BrowserContract.History;
 import org.mozilla.gecko.db.BrowserContract.Schema;
 import org.mozilla.gecko.db.BrowserContract.SyncColumns;
 import org.mozilla.gecko.db.BrowserContract.Thumbnails;
 import org.mozilla.gecko.sync.Utils;
 import android.app.SearchManager;
 import android.content.ContentProviderOperation;
 import android.content.ContentProviderResult;
 import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.OperationApplicationException;
 import android.content.UriMatcher;
 import android.database.Cursor;
 import android.database.DatabaseUtils;
 import android.database.MatrixCursor;
 import android.database.SQLException;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.net.Uri;
 import android.text.TextUtils;
 import android.util.Log;
 public class BrowserProvider extends SharedBrowserDatabaseProvider {
     private static final String LOGTAG = "GeckoBrowserProvider";
     // How many records to reposition in a single query.
     // This should be less than the SQLite maximum number of query variables
     // (currently 999) divided by the number of variables used per positioning
     // query (currently 3).
     static final int MAX_POSITION_UPDATES_PER_QUERY = 100;
     // Minimum number of records to keep when expiring history.
     static final int DEFAULT_EXPIRY_RETAIN_COUNT = 2000;
     static final int AGGRESSIVE_EXPIRY_RETAIN_COUNT = 500;
     // Minimum duration to keep when expiring.
     static final long DEFAULT_EXPIRY_PRESERVE_WINDOW = 1000L * 60L * 60L * 24L * 28L;     // Four weeks.
     // Minimum number of thumbnails to keep around.
     static final int DEFAULT_EXPIRY_THUMBNAIL_COUNT = 15;
     static final String TABLE_BOOKMARKS = Bookmarks.TABLE_NAME;
     static final String TABLE_HISTORY = History.TABLE_NAME;
     static final String TABLE_FAVICONS = Favicons.TABLE_NAME;
     static final String TABLE_THUMBNAILS = Thumbnails.TABLE_NAME;
     static final String VIEW_COMBINED = Combined.VIEW_NAME;
     static final String VIEW_BOOKMARKS_WITH_FAVICONS = Bookmarks.VIEW_WITH_FAVICONS;
     static final String VIEW_HISTORY_WITH_FAVICONS = History.VIEW_WITH_FAVICONS;
     static final String VIEW_COMBINED_WITH_FAVICONS = Combined.VIEW_WITH_FAVICONS;
     static final String VIEW_FLAGS = "flags";
     // Bookmark matches
     static final int BOOKMARKS = 100;
     static final int BOOKMARKS_ID = 101;
     static final int BOOKMARKS_FOLDER_ID = 102;
     static final int BOOKMARKS_PARENT = 103;
     static final int BOOKMARKS_POSITIONS = 104;
     // History matches
     static final int HISTORY = 200;
     static final int HISTORY_ID = 201;
     static final int HISTORY_OLD = 202;
     // Favicon matches
     static final int FAVICONS = 300;
     static final int FAVICON_ID = 301;
     // Schema matches
     static final int SCHEMA = 400;
     // Combined bookmarks and history matches
     static final int COMBINED = 500;
     // Control matches
     static final int CONTROL = 600;
     // Search Suggest matches
     static final int SEARCH_SUGGEST = 700;
     // Thumbnail matches
     static final int THUMBNAILS = 800;
     static final int THUMBNAIL_ID = 801;
     static final int FLAGS = 900;
     static final String DEFAULT_BOOKMARKS_SORT_ORDER = Bookmarks.TYPE
             + " ASC, " + Bookmarks.POSITION + " ASC, " + Bookmarks._ID
             + " ASC";
     static final String DEFAULT_HISTORY_SORT_ORDER = History.DATE_LAST_VISITED + " DESC";
     static final UriMatcher URI_MATCHER = new UriMatcher(UriMatcher.NO_MATCH);
     static final Map<String, String> BOOKMARKS_PROJECTION_MAP;
     static final Map<String, String> HISTORY_PROJECTION_MAP;
     static final Map<String, String> COMBINED_PROJECTION_MAP;
     static final Map<String, String> SCHEMA_PROJECTION_MAP;
     static final Map<String, String> SEARCH_SUGGEST_PROJECTION_MAP;
     static final Map<String, String> FAVICONS_PROJECTION_MAP;
     static final Map<String, String> THUMBNAILS_PROJECTION_MAP;
     static {
         // We will reuse this.
         HashMap<String, String> map;
         // Bookmarks
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "bookmarks", BOOKMARKS);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "bookmarks/#", BOOKMARKS_ID);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "bookmarks/parents", BOOKMARKS_PARENT);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "bookmarks/positions", BOOKMARKS_POSITIONS);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "bookmarks/folder/#", BOOKMARKS_FOLDER_ID);
         map = new HashMap<String, String>();
         map.put(Bookmarks._ID, Bookmarks._ID);
         map.put(Bookmarks.TITLE, Bookmarks.TITLE);
         map.put(Bookmarks.URL, Bookmarks.URL);
         map.put(Bookmarks.FAVICON, Bookmarks.FAVICON);
         map.put(Bookmarks.FAVICON_ID, Bookmarks.FAVICON_ID);
         map.put(Bookmarks.FAVICON_URL, Bookmarks.FAVICON_URL);
         map.put(Bookmarks.TYPE, Bookmarks.TYPE);
         map.put(Bookmarks.PARENT, Bookmarks.PARENT);
         map.put(Bookmarks.POSITION, Bookmarks.POSITION);
         map.put(Bookmarks.TAGS, Bookmarks.TAGS);
         map.put(Bookmarks.DESCRIPTION, Bookmarks.DESCRIPTION);
         map.put(Bookmarks.KEYWORD, Bookmarks.KEYWORD);
         map.put(Bookmarks.DATE_CREATED, Bookmarks.DATE_CREATED);
         map.put(Bookmarks.DATE_MODIFIED, Bookmarks.DATE_MODIFIED);
         map.put(Bookmarks.GUID, Bookmarks.GUID);
         map.put(Bookmarks.IS_DELETED, Bookmarks.IS_DELETED);
         BOOKMARKS_PROJECTION_MAP = Collections.unmodifiableMap(map);
         // History
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "history", HISTORY);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "history/#", HISTORY_ID);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "history/old", HISTORY_OLD);
         map = new HashMap<String, String>();
         map.put(History._ID, History._ID);
         map.put(History.TITLE, History.TITLE);
         map.put(History.URL, History.URL);
         map.put(History.FAVICON, History.FAVICON);
         map.put(History.FAVICON_ID, History.FAVICON_ID);
         map.put(History.FAVICON_URL, History.FAVICON_URL);
         map.put(History.VISITS, History.VISITS);
         map.put(History.DATE_LAST_VISITED, History.DATE_LAST_VISITED);
         map.put(History.DATE_CREATED, History.DATE_CREATED);
         map.put(History.DATE_MODIFIED, History.DATE_MODIFIED);
         map.put(History.GUID, History.GUID);
         map.put(History.IS_DELETED, History.IS_DELETED);
         HISTORY_PROJECTION_MAP = Collections.unmodifiableMap(map);
         // Favicons
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "favicons", FAVICONS);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "favicons/#", FAVICON_ID);
         map = new HashMap<String, String>();
         map.put(Favicons._ID, Favicons._ID);
         map.put(Favicons.URL, Favicons.URL);
         map.put(Favicons.DATA, Favicons.DATA);
         map.put(Favicons.DATE_CREATED, Favicons.DATE_CREATED);
         map.put(Favicons.DATE_MODIFIED, Favicons.DATE_MODIFIED);
         FAVICONS_PROJECTION_MAP = Collections.unmodifiableMap(map);
         // Thumbnails
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "thumbnails", THUMBNAILS);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "thumbnails/#", THUMBNAIL_ID);
         map = new HashMap<String, String>();
         map.put(Thumbnails._ID, Thumbnails._ID);
         map.put(Thumbnails.URL, Thumbnails.URL);
         map.put(Thumbnails.DATA, Thumbnails.DATA);
         THUMBNAILS_PROJECTION_MAP = Collections.unmodifiableMap(map);
         // Combined bookmarks and history
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "combined", COMBINED);
         map = new HashMap<String, String>();
         map.put(Combined._ID, Combined._ID);
         map.put(Combined.BOOKMARK_ID, Combined.BOOKMARK_ID);
         map.put(Combined.HISTORY_ID, Combined.HISTORY_ID);
         map.put(Combined.DISPLAY, "MAX(" + Combined.DISPLAY + ") AS " + Combined.DISPLAY);
         map.put(Combined.URL, Combined.URL);
         map.put(Combined.TITLE, Combined.TITLE);
         map.put(Combined.VISITS, Combined.VISITS);
         map.put(Combined.DATE_LAST_VISITED, Combined.DATE_LAST_VISITED);
         map.put(Combined.FAVICON, Combined.FAVICON);
         map.put(Combined.FAVICON_ID, Combined.FAVICON_ID);
         map.put(Combined.FAVICON_URL, Combined.FAVICON_URL);
         COMBINED_PROJECTION_MAP = Collections.unmodifiableMap(map);
         // Schema
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "schema", SCHEMA);
         map = new HashMap<String, String>();
         map.put(Schema.VERSION, Schema.VERSION);
         SCHEMA_PROJECTION_MAP = Collections.unmodifiableMap(map);
         // Control
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "control", CONTROL);
         // Search Suggest
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", SEARCH_SUGGEST);
         URI_MATCHER.addURI(BrowserContract.AUTHORITY, "flags", FLAGS);
         map = new HashMap<String, String>();
         map.put(SearchManager.SUGGEST_COLUMN_TEXT_1,
                 Combined.TITLE + " AS " + SearchManager.SUGGEST_COLUMN_TEXT_1);
         map.put(SearchManager.SUGGEST_COLUMN_TEXT_2_URL,
                 Combined.URL + " AS " + SearchManager.SUGGEST_COLUMN_TEXT_2_URL);
         map.put(SearchManager.SUGGEST_COLUMN_INTENT_DATA,
                 Combined.URL + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA);
         SEARCH_SUGGEST_PROJECTION_MAP = Collections.unmodifiableMap(map);
     }
     static final String qualifyColumn(String table, String column) {
         return table + "." + column;
     }
     private static boolean hasFaviconsInProjection(String[] projection) {
         if (projection == null) return true;
         for (int i = 0; i < projection.length; ++i) {
             if (projection[i].equals(FaviconColumns.FAVICON) ||
                 projection[i].equals(FaviconColumns.FAVICON_URL))
                 return true;
         }
         return false;
     }
     // Calculate these once, at initialization. isLoggable is too expensive to
     // have in-line in each log call.
     private static boolean logDebug   = Log.isLoggable(LOGTAG, Log.DEBUG);
     private static boolean logVerbose = Log.isLoggable(LOGTAG, Log.VERBOSE);
     protected static void trace(String message) {
         if (logVerbose) {
             Log.v(LOGTAG, message);
         }
     }
     protected static void debug(String message) {
         if (logDebug) {
             Log.d(LOGTAG, message);
         }
     }
     /**
      * Remove enough history items to bring the database count below <code>retain</code>,
      * removing no items with a modified time after <code>keepAfter</code>.
      *
      * Provide <code>keepAfter</code> less than or equal to zero to skip that check.
      *
      * Items will be removed according to an approximate frecency calculation.
      */
     private void expireHistory(final SQLiteDatabase db, final int retain, final long keepAfter) {
         Log.d(LOGTAG, "Expiring history.");
         final long rows = DatabaseUtils.queryNumEntries(db, TABLE_HISTORY);
         if (retain >= rows) {
             debug("Not expiring history: only have " + rows + " rows.");
             return;
         }
         final String sortOrder = BrowserContract.getFrecencySortOrder(false, true);
         final long toRemove = rows - retain;
         debug("Expiring at most " + toRemove + " rows earlier than " + keepAfter + ".");
         final String sql;
         if (keepAfter > 0) {
             sql = "DELETE FROM " + TABLE_HISTORY + " " +
                   "WHERE MAX(" + History.DATE_LAST_VISITED + ", " + History.DATE_MODIFIED +") < " + keepAfter + " " +
                   " AND " + History._ID + " IN ( SELECT " +
                     History._ID + " FROM " + TABLE_HISTORY + " " +
                     "ORDER BY " + sortOrder + " LIMIT " + toRemove +
                   ")";
         } else {
             sql = "DELETE FROM " + TABLE_HISTORY + " WHERE " + History._ID + " " +
                   "IN ( SELECT " + History._ID + " FROM " + TABLE_HISTORY + " " +
                   "ORDER BY " + sortOrder + " LIMIT " + toRemove + ")";
         }
         trace("Deleting using query: " + sql);
         beginWrite(db);
         db.execSQL(sql);
     }
     /**
      * Remove any thumbnails that for sites that aren't likely to be ever shown.
      * Items will be removed according to a frecency calculation and only if they are not pinned
      *
      * Call this method within a transaction.
      */
     private void expireThumbnails(final SQLiteDatabase db) {
         Log.d(LOGTAG, "Expiring thumbnails.");
         final String sortOrder = BrowserContract.getFrecencySortOrder(true, false);
         final String sql = "DELETE FROM " + TABLE_THUMBNAILS +
                            " WHERE " + Thumbnails.URL + " NOT IN ( " +
                              " SELECT " + Combined.URL +
                              " FROM " + Combined.VIEW_NAME +
                              " ORDER BY " + sortOrder +
                              " LIMIT " + DEFAULT_EXPIRY_THUMBNAIL_COUNT +
                            ") AND " + Thumbnails.URL + " NOT IN ( " +
                              " SELECT " + Bookmarks.URL +
                              " FROM " + TABLE_BOOKMARKS +
                              " WHERE " + Bookmarks.PARENT + " = " + Bookmarks.FIXED_PINNED_LIST_ID +
                            ")";
         trace("Clear thumbs using query: " + sql);
         db.execSQL(sql);
     }
     private boolean shouldIncrementVisits(Uri uri) {
         String incrementVisits = uri.getQueryParameter(BrowserContract.PARAM_INCREMENT_VISITS);
         return Boolean.parseBoolean(incrementVisits);
     }
     @Override
     public String getType(Uri uri) {
         final int match = URI_MATCHER.match(uri);
         trace("Getting URI type: " + uri);
         switch (match) {
             case BOOKMARKS:
                 trace("URI is BOOKMARKS: " + uri);
                 return Bookmarks.CONTENT_TYPE;
             case BOOKMARKS_ID:
                 trace("URI is BOOKMARKS_ID: " + uri);
                 return Bookmarks.CONTENT_ITEM_TYPE;
             case HISTORY:
                 trace("URI is HISTORY: " + uri);
                 return History.CONTENT_TYPE;
             case HISTORY_ID:
                 trace("URI is HISTORY_ID: " + uri);
                 return History.CONTENT_ITEM_TYPE;
             case SEARCH_SUGGEST:
                 trace("URI is SEARCH_SUGGEST: " + uri);
                 return SearchManager.SUGGEST_MIME_TYPE;
             case FLAGS:
                 trace("URI is FLAGS.");
                 return Bookmarks.CONTENT_ITEM_TYPE;
         }
         debug("URI has unrecognized type: " + uri);
         return null;
     }
     @SuppressWarnings("fallthrough")
     @Override
     public int deleteInTransaction(Uri uri, String selection, String[] selectionArgs) {
         trace("Calling delete in transaction on URI: " + uri);
         final SQLiteDatabase db = getWritableDatabase(uri);
         final int match = URI_MATCHER.match(uri);
         int deleted = 0;
         switch (match) {
             case BOOKMARKS_ID:
                 trace("Delete on BOOKMARKS_ID: " + uri);
                 selection = DBUtils.concatenateWhere(selection, TABLE_BOOKMARKS + "._id = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case BOOKMARKS: {
                 trace("Deleting bookmarks: " + uri);
                 deleted = deleteBookmarks(uri, selection, selectionArgs);
                 deleteUnusedImages(uri);
                 break;
             }
             case HISTORY_ID:
                 trace("Delete on HISTORY_ID: " + uri);
                 selection = DBUtils.concatenateWhere(selection, TABLE_HISTORY + "._id = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case HISTORY: {
                 trace("Deleting history: " + uri);
                 beginWrite(db);
                 deleted = deleteHistory(uri, selection, selectionArgs);
                 deleteUnusedImages(uri);
                 break;
             }
             case HISTORY_OLD: {
                 String priority = uri.getQueryParameter(BrowserContract.PARAM_EXPIRE_PRIORITY);
                 long keepAfter = System.currentTimeMillis() - DEFAULT_EXPIRY_PRESERVE_WINDOW;
                 int retainCount = DEFAULT_EXPIRY_RETAIN_COUNT;
                 if (BrowserContract.ExpirePriority.AGGRESSIVE.toString().equals(priority)) {
                     keepAfter = 0;
                     retainCount = AGGRESSIVE_EXPIRY_RETAIN_COUNT;
                 }
                 expireHistory(db, retainCount, keepAfter);
                 expireThumbnails(db);
                 deleteUnusedImages(uri);
                 break;
             }
             case FAVICON_ID:
                 debug("Delete on FAVICON_ID: " + uri);
                 selection = DBUtils.concatenateWhere(selection, TABLE_FAVICONS + "._id = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case FAVICONS: {
                 trace("Deleting favicons: " + uri);
                 beginWrite(db);
                 deleted = deleteFavicons(uri, selection, selectionArgs);
                 break;
             }
             case THUMBNAIL_ID:
                 debug("Delete on THUMBNAIL_ID: " + uri);
                 selection = DBUtils.concatenateWhere(selection, TABLE_THUMBNAILS + "._id = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case THUMBNAILS: {
                 trace("Deleting thumbnails: " + uri);
                 beginWrite(db);
                 deleted = deleteThumbnails(uri, selection, selectionArgs);
                 break;
             }
             default:
                 throw new UnsupportedOperationException("Unknown delete URI " + uri);
         }
         debug("Deleted " + deleted + " rows for URI: " + uri);
         return deleted;
     }
     @Override
     public Uri insertInTransaction(Uri uri, ContentValues values) {
         trace("Calling insert in transaction on URI: " + uri);
         int match = URI_MATCHER.match(uri);
         long id = -1;
         switch (match) {
             case BOOKMARKS: {
                 trace("Insert on BOOKMARKS: " + uri);
                 id = insertBookmark(uri, values);
                 break;
             }
             case HISTORY: {
                 trace("Insert on HISTORY: " + uri);
                 id = insertHistory(uri, values);
                 break;
             }
             case FAVICONS: {
                 trace("Insert on FAVICONS: " + uri);
                 id = insertFavicon(uri, values);
                 break;
             }
             case THUMBNAILS: {
                 trace("Insert on THUMBNAILS: " + uri);
                 id = insertThumbnail(uri, values);
                 break;
             }
             default:
                 throw new UnsupportedOperationException("Unknown insert URI " + uri);
         }
         debug("Inserted ID in database: " + id);
         if (id >= 0)
             return ContentUris.withAppendedId(uri, id);
         return null;
     }
     @SuppressWarnings("fallthrough")
     @Override
     public int updateInTransaction(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         trace("Calling update in transaction on URI: " + uri);
         int match = URI_MATCHER.match(uri);
         int updated = 0;
         final SQLiteDatabase db = getWritableDatabase(uri);
         switch (match) {
             // We provide a dedicated (hacky) API for callers to bulk-update the positions of
             // folder children by passing an array of GUID strings as `selectionArgs`.
             // Each child will have its position column set to its index in the provided array.
             //
             // This avoids callers having to issue a large number of UPDATE queries through
             // the usual channels. See Bug 728783.
             //
             // Note that this is decidedly not a general-purpose API; use at your own risk.
             // `values` and `selection` are ignored.
             case BOOKMARKS_POSITIONS: {
                 debug("Update on BOOKMARKS_POSITIONS: " + uri);
                 // This already starts and finishes its own transaction.
                 updated = updateBookmarkPositions(uri, selectionArgs);
                 break;
             }
             case BOOKMARKS_PARENT: {
                 debug("Update on BOOKMARKS_PARENT: " + uri);
                 beginWrite(db);
                 updated = updateBookmarkParents(db, values, selection, selectionArgs);
                 break;
             }
             case BOOKMARKS_ID:
                 debug("Update on BOOKMARKS_ID: " + uri);
                 selection = DBUtils.concatenateWhere(selection, TABLE_BOOKMARKS + "._id = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case BOOKMARKS: {
                 debug("Updating bookmark: " + uri);
                 if (shouldUpdateOrInsert(uri)) {
                     updated = updateOrInsertBookmark(uri, values, selection, selectionArgs);
                 } else {
                     updated = updateBookmarks(uri, values, selection, selectionArgs);
                 }
                 break;
             }
             case HISTORY_ID:
                 debug("Update on HISTORY_ID: " + uri);
                 selection = DBUtils.concatenateWhere(selection, TABLE_HISTORY + "._id = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case HISTORY: {
                 debug("Updating history: " + uri);
                 if (shouldUpdateOrInsert(uri)) {
                     updated = updateOrInsertHistory(uri, values, selection, selectionArgs);
                 } else {
                     updated = updateHistory(uri, values, selection, selectionArgs);
                 }
                 break;
             }
             case FAVICONS: {
                 debug("Update on FAVICONS: " + uri);
                 String url = values.getAsString(Favicons.URL);
                 String faviconSelection = null;
                 String[] faviconSelectionArgs = null;
                 if (!TextUtils.isEmpty(url)) {
                     faviconSelection = Favicons.URL + " = ?";
                     faviconSelectionArgs = new String[] { url };
                 }
                 if (shouldUpdateOrInsert(uri)) {
                     updated = updateOrInsertFavicon(uri, values, faviconSelection, faviconSelectionArgs);
                 } else {
                     updated = updateExistingFavicon(uri, values, faviconSelection, faviconSelectionArgs);
                 }
                 break;
             }
             case THUMBNAILS: {
                 debug("Update on THUMBNAILS: " + uri);
                 String url = values.getAsString(Thumbnails.URL);
                 // if no URL is provided, update all of the entries
                 if (TextUtils.isEmpty(values.getAsString(Thumbnails.URL))) {
                     updated = updateExistingThumbnail(uri, values, null, null);
                 } else if (shouldUpdateOrInsert(uri)) {
                     updated = updateOrInsertThumbnail(uri, values, Thumbnails.URL + " = ?",
                                                       new String[] { url });
                 } else {
                     updated = updateExistingThumbnail(uri, values, Thumbnails.URL + " = ?",
                                                       new String[] { url });
                 }
                 break;
             }
             default:
                 throw new UnsupportedOperationException("Unknown update URI " + uri);
         }
         debug("Updated " + updated + " rows for URI: " + uri);
         return updated;
     }
     @Override
     public Cursor query(Uri uri, String[] projection, String selection,
             String[] selectionArgs, String sortOrder) {
         SQLiteDatabase db = getReadableDatabase(uri);
         final int match = URI_MATCHER.match(uri);
         // The first selectionArgs value is the URI for which to query.
         if (match == FLAGS) {
             // We don't need the QB below for this.
             //
             // There are three possible kinds of bookmarks:
             // * Regular bookmarks
             // * Bookmarks whose parent is FIXED_READING_LIST_ID (reading list items)
             // * Bookmarks whose parent is FIXED_PINNED_LIST_ID (pinned items).
             //
             // Although SQLite doesn't have an aggregate operator for bitwise-OR, we're
             // using disjoint flags, so we can simply use SUM and DISTINCT to get the
             // flags we need.
             // We turn parents into flags according to the three kinds, above.
             //
             // When this query is extended to support queries across multiple tables, simply
             // extend it to look like
             //
             // SELECT COALESCE((SELECT ...), 0) | COALESCE(...) | ...
             final boolean includeDeleted = shouldShowDeleted(uri);
             final String query = "SELECT COALESCE(SUM(flag), 0) AS flags " +
                 "FROM ( SELECT DISTINCT CASE" +
                 " WHEN " + Bookmarks.PARENT + " = " + Bookmarks.FIXED_READING_LIST_ID +
                 " THEN " + Bookmarks.FLAG_READING +
                 " WHEN " + Bookmarks.PARENT + " = " + Bookmarks.FIXED_PINNED_LIST_ID +
                 " THEN " + Bookmarks.FLAG_PINNED +
                 " ELSE " + Bookmarks.FLAG_BOOKMARK +
                 " END flag " +
                 "FROM " + TABLE_BOOKMARKS + " WHERE " +
                 Bookmarks.URL + " = ? " +
                 (includeDeleted ? "" : ("AND " + Bookmarks.IS_DELETED + " = 0")) +
                 ")";
             return db.rawQuery(query, selectionArgs);
         }
         SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
         String limit = uri.getQueryParameter(BrowserContract.PARAM_LIMIT);
         String groupBy = null;
         switch (match) {
             case BOOKMARKS_FOLDER_ID:
             case BOOKMARKS_ID:
             case BOOKMARKS: {
                 debug("Query is on bookmarks: " + uri);
                 if (match == BOOKMARKS_ID) {
                     selection = DBUtils.concatenateWhere(selection, Bookmarks._ID + " = ?");
                     selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                             new String[] { Long.toString(ContentUris.parseId(uri)) });
                 } else if (match == BOOKMARKS_FOLDER_ID) {
                     selection = DBUtils.concatenateWhere(selection, Bookmarks.PARENT + " = ?");
                     selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                             new String[] { Long.toString(ContentUris.parseId(uri)) });
                 }
                 if (!shouldShowDeleted(uri))
                     selection = DBUtils.concatenateWhere(Bookmarks.IS_DELETED + " = 0", selection);
                 if (TextUtils.isEmpty(sortOrder)) {
                     sortOrder = DEFAULT_BOOKMARKS_SORT_ORDER;
                 } else {
                     debug("Using sort order " + sortOrder + ".");
                 }
                 qb.setProjectionMap(BOOKMARKS_PROJECTION_MAP);
                 if (hasFaviconsInProjection(projection))
                     qb.setTables(VIEW_BOOKMARKS_WITH_FAVICONS);
                 else
                     qb.setTables(TABLE_BOOKMARKS);
                 break;
             }
             case HISTORY_ID:
                 selection = DBUtils.concatenateWhere(selection, History._ID + " = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case HISTORY: {
                 debug("Query is on history: " + uri);
                 if (!shouldShowDeleted(uri))
                     selection = DBUtils.concatenateWhere(History.IS_DELETED + " = 0", selection);
                 if (TextUtils.isEmpty(sortOrder))
                     sortOrder = DEFAULT_HISTORY_SORT_ORDER;
                 qb.setProjectionMap(HISTORY_PROJECTION_MAP);
                 if (hasFaviconsInProjection(projection))
                     qb.setTables(VIEW_HISTORY_WITH_FAVICONS);
                 else
                     qb.setTables(TABLE_HISTORY);
                 break;
             }
             case FAVICON_ID:
                 selection = DBUtils.concatenateWhere(selection, Favicons._ID + " = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case FAVICONS: {
                 debug("Query is on favicons: " + uri);
                 qb.setProjectionMap(FAVICONS_PROJECTION_MAP);
                 qb.setTables(TABLE_FAVICONS);
                 break;
             }
             case THUMBNAIL_ID:
                 selection = DBUtils.concatenateWhere(selection, Thumbnails._ID + " = ?");
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { Long.toString(ContentUris.parseId(uri)) });
                 // fall through
             case THUMBNAILS: {
                 debug("Query is on thumbnails: " + uri);
                 qb.setProjectionMap(THUMBNAILS_PROJECTION_MAP);
                 qb.setTables(TABLE_THUMBNAILS);
                 break;
             }
             case SCHEMA: {
                 debug("Query is on schema.");
                 MatrixCursor schemaCursor = new MatrixCursor(new String[] { Schema.VERSION });
                 schemaCursor.newRow().add(BrowserDatabaseHelper.DATABASE_VERSION);
                 return schemaCursor;
             }
             case COMBINED: {
                 debug("Query is on combined: " + uri);
                 if (TextUtils.isEmpty(sortOrder))
                     sortOrder = DEFAULT_HISTORY_SORT_ORDER;
                 // This will avoid duplicate entries in the awesomebar
                 // results when a history entry has multiple bookmarks.
                 groupBy = Combined.URL;
                 qb.setProjectionMap(COMBINED_PROJECTION_MAP);
                 if (hasFaviconsInProjection(projection))
                     qb.setTables(VIEW_COMBINED_WITH_FAVICONS);
                 else
                     qb.setTables(Combined.VIEW_NAME);
                 break;
             }
             case SEARCH_SUGGEST: {
                 debug("Query is on search suggest: " + uri);
                 selection = DBUtils.concatenateWhere(selection, "(" + Combined.URL + " LIKE ? OR " +
                                                                       Combined.TITLE + " LIKE ?)");
                 String keyword = uri.getLastPathSegment();
                 if (keyword == null)
                     keyword = "";
                 selectionArgs = DBUtils.appendSelectionArgs(selectionArgs,
                         new String[] { "%" + keyword + "%",
                                        "%" + keyword + "%" });
                 if (TextUtils.isEmpty(sortOrder))
                     sortOrder = DEFAULT_HISTORY_SORT_ORDER;
                 qb.setProjectionMap(SEARCH_SUGGEST_PROJECTION_MAP);
                 qb.setTables(VIEW_COMBINED_WITH_FAVICONS);
                 break;
             }
             default:
                 throw new UnsupportedOperationException("Unknown query URI " + uri);
         }
         trace("Running built query.");
         Cursor cursor = qb.query(db, projection, selection, selectionArgs, groupBy,
                 null, sortOrder, limit);
         cursor.setNotificationUri(getContext().getContentResolver(),
                 BrowserContract.AUTHORITY_URI);
         return cursor;
     }
     /**
      * Update the positions of bookmarks in batches.
      *
      * Begins and ends its own transactions.
      *
      * @see #updateBookmarkPositionsInTransaction(SQLiteDatabase, String[], int, int)
      */
     int updateBookmarkPositions(Uri uri, String[] guids) {
         if (guids == null) {
             return 0;
         }
         int guidsCount = guids.length;
         if (guidsCount == 0) {
             return 0;
         }
         int offset = 0;
         int updated = 0;
         final SQLiteDatabase db = getWritableDatabase(uri);
         db.beginTransaction();
         while (offset < guidsCount) {
             try {
                 updated += updateBookmarkPositionsInTransaction(db, guids, offset,
                                                                 MAX_POSITION_UPDATES_PER_QUERY);
             } catch (SQLException e) {
                 Log.e(LOGTAG, "Got SQLite exception updating bookmark positions at offset " + offset, e);
                 // Need to restart the transaction.
                 // The only way a caller knows that anything failed is that the
                 // returned update count will be smaller than the requested
                 // number of records.
                 db.setTransactionSuccessful();
                 db.endTransaction();
                 db.beginTransaction();
             }
             offset += MAX_POSITION_UPDATES_PER_QUERY;
         }
         db.setTransactionSuccessful();
         db.endTransaction();
         return updated;
     }
     /**
      * Construct and execute an update expression that will modify the positions
      * of records in-place.
      */
     private static int updateBookmarkPositionsInTransaction(final SQLiteDatabase db, final String[] guids,
                                                             final int offset, final int max) {
         int guidsCount = guids.length;
         int processCount = Math.min(max, guidsCount - offset);
         // Each must appear twice: once in a CASE, and once in the IN clause.
         String[] args = new String[processCount * 2];
         System.arraycopy(guids, offset, args, 0, processCount);
         System.arraycopy(guids, offset, args, processCount, processCount);
         StringBuilder b = new StringBuilder("UPDATE " + TABLE_BOOKMARKS +
                                             " SET " + Bookmarks.POSITION +
                                             " = CASE guid");
         // Build the CASE statement body for GUID/index pairs from offset up to
         // the computed limit.
         final int end = offset + processCount;
         int i = offset;
         for (; i < end; ++i) {
             if (guids[i] == null) {
                 // We don't want to issue the query if not every GUID is specified.
                 debug("updateBookmarkPositions called with null GUID at index " + i);
                 return 0;
             }
             b.append(" WHEN ? THEN " + i);
         }
         // TODO: use computeSQLInClause
         b.append(" END WHERE " + Bookmarks.GUID + " IN (");
         i = 1;
         while (i++ < processCount) {
             b.append("?, ");
         }
         b.append("?)");
         db.execSQL(b.toString(), args);
         // We can't easily get a modified count without calling something like changes().
         return processCount;
     }
     /**
      * Construct an update expression that will modify the parents of any records
      * that match.
      */
     private int updateBookmarkParents(SQLiteDatabase db, ContentValues values, String selection, String[] selectionArgs) {
         trace("Updating bookmark parents of " + selection + " (" + selectionArgs[0] + ")");
         String where = Bookmarks._ID + " IN (" +
                        " SELECT DISTINCT " + Bookmarks.PARENT +
                        " FROM " + TABLE_BOOKMARKS +
                        " WHERE " + selection + " )";
         return db.update(TABLE_BOOKMARKS, values, where, selectionArgs);
     }
     long insertBookmark(Uri uri, ContentValues values) {
         // Generate values if not specified. Don't overwrite
         // if specified by caller.
         long now = System.currentTimeMillis();
         if (!values.containsKey(Bookmarks.DATE_CREATED)) {
             values.put(Bookmarks.DATE_CREATED, now);
         }
         if (!values.containsKey(Bookmarks.DATE_MODIFIED)) {
             values.put(Bookmarks.DATE_MODIFIED, now);
         }
         if (!values.containsKey(Bookmarks.GUID)) {
             values.put(Bookmarks.GUID, Utils.generateGuid());
         }
         if (!values.containsKey(Bookmarks.POSITION)) {
             debug("Inserting bookmark with no position for URI");
             values.put(Bookmarks.POSITION,
                        Long.toString(BrowserContract.Bookmarks.DEFAULT_POSITION));
         }
         String url = values.getAsString(Bookmarks.URL);
         debug("Inserting bookmark in database with URL: " + url);
         final SQLiteDatabase db = getWritableDatabase(uri);
         beginWrite(db);
         return db.insertOrThrow(TABLE_BOOKMARKS, Bookmarks.TITLE, values);
     }
     int updateOrInsertBookmark(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         int updated = updateBookmarks(uri, values, selection, selectionArgs);
         if (updated > 0) {
             return updated;
         }
         // Transaction already begun by updateBookmarks.
         if (0 <= insertBookmark(uri, values)) {
             // We 'updated' one row.
             return 1;
         }
         // If something went wrong, then we updated zero rows.
         return 0;
     }
     int updateBookmarks(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         trace("Updating bookmarks on URI: " + uri);
         final String[] bookmarksProjection = new String[] {
                 Bookmarks._ID, // 0
         };
         if (!values.containsKey(Bookmarks.DATE_MODIFIED)) {
             values.put(Bookmarks.DATE_MODIFIED, System.currentTimeMillis());
         }
         trace("Querying bookmarks to update on URI: " + uri);
         final SQLiteDatabase db = getWritableDatabase(uri);
         // Compute matching IDs.
         final Cursor cursor = db.query(TABLE_BOOKMARKS, bookmarksProjection,
                                        selection, selectionArgs, null, null, null);
         // Now that we're done reading, open a transaction.
         final String inClause;
         try {
             inClause = computeSQLInClauseFromLongs(cursor, Bookmarks._ID);
         } finally {
             cursor.close();
         }
         beginWrite(db);
         return db.update(TABLE_BOOKMARKS, values, inClause, null);
     }
     long insertHistory(Uri uri, ContentValues values) {
         final long now = System.currentTimeMillis();
         values.put(History.DATE_CREATED, now);
         values.put(History.DATE_MODIFIED, now);
         // Generate GUID for new history entry. Don't override specified GUIDs.
         if (!values.containsKey(History.GUID)) {
           values.put(History.GUID, Utils.generateGuid());
         }
         String url = values.getAsString(History.URL);
         debug("Inserting history in database with URL: " + url);
         final SQLiteDatabase db = getWritableDatabase(uri);
         beginWrite(db);
         return db.insertOrThrow(TABLE_HISTORY, History.VISITS, values);
     }
     int updateOrInsertHistory(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         final int updated = updateHistory(uri, values, selection, selectionArgs);
         if (updated > 0) {
             return updated;
         }
         // Insert a new entry if necessary
         if (!values.containsKey(History.VISITS)) {
             values.put(History.VISITS, 1);
         }
         if (!values.containsKey(History.TITLE)) {
             values.put(History.TITLE, values.getAsString(History.URL));
         }
         if (0 <= insertHistory(uri, values)) {
             return 1;
         }
         return 0;
     }
     int updateHistory(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         trace("Updating history on URI: " + uri);
         int updated = 0;
         final String[] historyProjection = new String[] {
             History._ID,   // 0
             History.URL,   // 1
             History.VISITS // 2
         };
         final SQLiteDatabase db = getWritableDatabase(uri);
         final Cursor cursor = db.query(TABLE_HISTORY, historyProjection, selection,
                                        selectionArgs, null, null, null);
         try {
             if (!values.containsKey(Bookmarks.DATE_MODIFIED)) {
                 values.put(Bookmarks.DATE_MODIFIED,  System.currentTimeMillis());
             }
             while (cursor.moveToNext()) {
                 long id = cursor.getLong(0);
                 trace("Updating history entry with ID: " + id);
                 if (shouldIncrementVisits(uri)) {
                     long existing = cursor.getLong(2);
                     Long additional = values.getAsLong(History.VISITS);
                     // Increment visit count by a specified amount, or default to increment by 1
                     values.put(History.VISITS, existing + ((additional != null) ? additional.longValue() : 1));
                 }
                 updated += db.update(TABLE_HISTORY, values, "_id = ?",
                                      new String[] { Long.toString(id) });
             }
         } finally {
             cursor.close();
         }
         return updated;
     }
     private void updateFaviconIdsForUrl(SQLiteDatabase db, String pageUrl, Long faviconId) {
         ContentValues updateValues = new ContentValues(1);
         updateValues.put(FaviconColumns.FAVICON_ID, faviconId);
         db.update(TABLE_HISTORY,
                   updateValues,
                   History.URL + " = ?",
                   new String[] { pageUrl });
         db.update(TABLE_BOOKMARKS,
                   updateValues,
                   Bookmarks.URL + " = ?",
                   new String[] { pageUrl });
     }
     long insertFavicon(Uri uri, ContentValues values) {
         return insertFavicon(getWritableDatabase(uri), values);
     }
     long insertFavicon(SQLiteDatabase db, ContentValues values) {
         // This method is a dupicate of BrowserDatabaseHelper.insertFavicon.
         // If changes are needed, please update both
         String faviconUrl = values.getAsString(Favicons.URL);
         String pageUrl = null;
         trace("Inserting favicon for URL: " + faviconUrl);
         DBUtils.stripEmptyByteArray(values, Favicons.DATA);
         // Extract the page URL from the ContentValues
         if (values.containsKey(Favicons.PAGE_URL)) {
             pageUrl = values.getAsString(Favicons.PAGE_URL);
             values.remove(Favicons.PAGE_URL);
         }
         // If no URL is provided, insert using the default one.
         if (TextUtils.isEmpty(faviconUrl) && !TextUtils.isEmpty(pageUrl)) {
             values.put(Favicons.URL, org.mozilla.gecko.favicons.Favicons.guessDefaultFaviconURL(pageUrl));
         }
         final long now = System.currentTimeMillis();
         values.put(Favicons.DATE_CREATED, now);
         values.put(Favicons.DATE_MODIFIED, now);
         beginWrite(db);
         final long faviconId = db.insertOrThrow(TABLE_FAVICONS, null, values);
         if (pageUrl != null) {
             updateFaviconIdsForUrl(db, pageUrl, faviconId);
         }
         return faviconId;
     }
     int updateOrInsertFavicon(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         return updateFavicon(uri, values, selection, selectionArgs,
                 true /* insert if needed */);
     }
     int updateExistingFavicon(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         return updateFavicon(uri, values, selection, selectionArgs,
                 false /* only update, no insert */);
     }
     int updateFavicon(Uri uri, ContentValues values, String selection,
             String[] selectionArgs, boolean insertIfNeeded) {
         String faviconUrl = values.getAsString(Favicons.URL);
         String pageUrl = null;
         int updated = 0;
         Long faviconId = null;
         long now = System.currentTimeMillis();
         trace("Updating favicon for URL: " + faviconUrl);
         DBUtils.stripEmptyByteArray(values, Favicons.DATA);
         // Extract the page URL from the ContentValues
         if (values.containsKey(Favicons.PAGE_URL)) {
             pageUrl = values.getAsString(Favicons.PAGE_URL);
             values.remove(Favicons.PAGE_URL);
         }
         values.put(Favicons.DATE_MODIFIED, now);
         final SQLiteDatabase db = getWritableDatabase(uri);
         // If there's no favicon URL given and we're inserting if needed, skip
         // the update and only do an insert (otherwise all rows would be
         // updated).
         if (!(insertIfNeeded && (faviconUrl == null))) {
             updated = db.update(TABLE_FAVICONS, values, selection, selectionArgs);
         }
         if (updated > 0) {
             if ((faviconUrl != null) && (pageUrl != null)) {
                 final Cursor cursor = db.query(TABLE_FAVICONS,
                                                new String[] { Favicons._ID },
                                                Favicons.URL + " = ?",
                                                new String[] { faviconUrl },
                                                null, null, null);
                 try {
                     if (cursor.moveToFirst()) {
                         faviconId = cursor.getLong(cursor.getColumnIndexOrThrow(Favicons._ID));
                     }
                 } finally {
                     cursor.close();
                 }
             }
             if (pageUrl != null) {
                 beginWrite(db);
             }
         } else if (insertIfNeeded) {
             values.put(Favicons.DATE_CREATED, now);
             trace("No update, inserting favicon for URL: " + faviconUrl);
             beginWrite(db);
             faviconId = db.insert(TABLE_FAVICONS, null, values);
             updated = 1;
         }
         if (pageUrl != null) {
             updateFaviconIdsForUrl(db, pageUrl, faviconId);
         }
         return updated;
     }
     private long insertThumbnail(Uri uri, ContentValues values) {
         final String url = values.getAsString(Thumbnails.URL);
         trace("Inserting thumbnail for URL: " + url);
         DBUtils.stripEmptyByteArray(values, Thumbnails.DATA);
         final SQLiteDatabase db = getWritableDatabase(uri);
         beginWrite(db);
         return db.insertOrThrow(TABLE_THUMBNAILS, null, values);
     }
     private int updateOrInsertThumbnail(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         return updateThumbnail(uri, values, selection, selectionArgs,
                 true /* insert if needed */);
     }
     private int updateExistingThumbnail(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         return updateThumbnail(uri, values, selection, selectionArgs,
                 false /* only update, no insert */);
     }
     private int updateThumbnail(Uri uri, ContentValues values, String selection,
             String[] selectionArgs, boolean insertIfNeeded) {
         final String url = values.getAsString(Thumbnails.URL);
         DBUtils.stripEmptyByteArray(values, Thumbnails.DATA);
         trace("Updating thumbnail for URL: " + url);
         final SQLiteDatabase db = getWritableDatabase(uri);
         beginWrite(db);
         int updated = db.update(TABLE_THUMBNAILS, values, selection, selectionArgs);
         if (updated == 0 && insertIfNeeded) {
             trace("No update, inserting thumbnail for URL: " + url);
             db.insert(TABLE_THUMBNAILS, null, values);
             updated = 1;
         }
         return updated;
     }
     /**
      * This method does not create a new transaction. Its first operation is
      * guaranteed to be a write, which in the case of a new enclosing
      * transaction will guarantee that a read does not need to be upgraded to
      * a write.
      */
     int deleteHistory(Uri uri, String selection, String[] selectionArgs) {
         debug("Deleting history entry for URI: " + uri);
         final SQLiteDatabase db = getWritableDatabase(uri);
         if (isCallerSync(uri)) {
             return db.delete(TABLE_HISTORY, selection, selectionArgs);
         }
         debug("Marking history entry as deleted for URI: " + uri);
         ContentValues values = new ContentValues();
         values.put(History.IS_DELETED, 1);
         // Wipe sensitive data.
         values.putNull(History.TITLE);
         values.put(History.URL, "");          // Column is NOT NULL.
         values.put(History.DATE_CREATED, 0);
         values.put(History.DATE_LAST_VISITED, 0);
         values.put(History.VISITS, 0);
         values.put(History.DATE_MODIFIED, System.currentTimeMillis());
         // Doing this UPDATE (or the DELETE above) first ensures that the
         // first operation within a new enclosing transaction is a write.
         // The cleanup call below will do a SELECT first, and thus would
         // require the transaction to be upgraded from a reader to a writer.
         // In some cases that upgrade can fail (SQLITE_BUSY), so we avoid
         // it if we can.
         final int updated = db.update(TABLE_HISTORY, values, selection, selectionArgs);
         try {
             cleanUpSomeDeletedRecords(uri, TABLE_HISTORY);
         } catch (Exception e) {
             // We don't care.
             Log.e(LOGTAG, "Unable to clean up deleted history records: ", e);
         }
         return updated;
     }
     int deleteBookmarks(Uri uri, String selection, String[] selectionArgs) {
         debug("Deleting bookmarks for URI: " + uri);
         final SQLiteDatabase db = getWritableDatabase(uri);
         if (isCallerSync(uri)) {
             beginWrite(db);
             return db.delete(TABLE_BOOKMARKS, selection, selectionArgs);
         }
         debug("Marking bookmarks as deleted for URI: " + uri);
         ContentValues values = new ContentValues();
         values.put(Bookmarks.IS_DELETED, 1);
         // Doing this UPDATE (or the DELETE above) first ensures that the
         // first operation within this transaction is a write.
         // The cleanup call below will do a SELECT first, and thus would
         // require the transaction to be upgraded from a reader to a writer.
         final int updated = updateBookmarks(uri, values, selection, selectionArgs);
         try {
             cleanUpSomeDeletedRecords(uri, TABLE_BOOKMARKS);
         } catch (Exception e) {
             // We don't care.
             Log.e(LOGTAG, "Unable to clean up deleted bookmark records: ", e);
         }
         return updated;
     }
     int deleteFavicons(Uri uri, String selection, String[] selectionArgs) {
         debug("Deleting favicons for URI: " + uri);
         final SQLiteDatabase db = getWritableDatabase(uri);
         return db.delete(TABLE_FAVICONS, selection, selectionArgs);
     }
     int deleteThumbnails(Uri uri, String selection, String[] selectionArgs) {
         debug("Deleting thumbnails for URI: " + uri);
         final SQLiteDatabase db = getWritableDatabase(uri);
         return db.delete(TABLE_THUMBNAILS, selection, selectionArgs);
     }
     int deleteUnusedImages(Uri uri) {
         debug("Deleting all unused favicons and thumbnails for URI: " + uri);
         String faviconSelection = Favicons._ID + " NOT IN "
                 + "(SELECT " + History.FAVICON_ID
                 + " FROM " + TABLE_HISTORY
                 + " WHERE " + History.IS_DELETED + " = 0"
                 + " AND " + History.FAVICON_ID + " IS NOT NULL"
                 + " UNION ALL SELECT " + Bookmarks.FAVICON_ID
                 + " FROM " + TABLE_BOOKMARKS
                 + " WHERE " + Bookmarks.IS_DELETED + " = 0"
                 + " AND " + Bookmarks.FAVICON_ID + " IS NOT NULL)";
         String thumbnailSelection = Thumbnails.URL + " NOT IN "
                 + "(SELECT " + History.URL
                 + " FROM " + TABLE_HISTORY
                 + " WHERE " + History.IS_DELETED + " = 0"
                 + " AND " + History.URL + " IS NOT NULL"
                 + " UNION ALL SELECT " + Bookmarks.URL
                 + " FROM " + TABLE_BOOKMARKS
                 + " WHERE " + Bookmarks.IS_DELETED + " = 0"
                 + " AND " + Bookmarks.URL + " IS NOT NULL)";
         return deleteFavicons(uri, faviconSelection, null) +
                deleteThumbnails(uri, thumbnailSelection, null);
     }
     @Override
     public ContentProviderResult[] applyBatch (ArrayList<ContentProviderOperation> operations)
         throws OperationApplicationException {
         final int numOperations = operations.size();
         final ContentProviderResult[] results = new ContentProviderResult[numOperations];
         if (numOperations < 1) {
             debug("applyBatch: no operations; returning immediately.");
             // The original Android implementation returns a zero-length
             // array in this case. We do the same.
             return results;
         }
         boolean failures = false;
         // We only have 1 database for all Uris that we can get.
         SQLiteDatabase db = getWritableDatabase(operations.get(0).getUri());
         // Note that the apply() call may cause us to generate
         // additional transactions for the individual operations.
         // But Android's wrapper for SQLite supports nested transactions,
         // so this will do the right thing.
         //
         // Note further that in some circumstances this can result in
         // exceptions: if this transaction is first involved in reading,
         // and then (naturally) tries to perform writes, SQLITE_BUSY can
         // be raised. See Bug 947939 and friends.
         beginBatch(db);
         for (int i = 0; i < numOperations; i++) {
             try {
                 final ContentProviderOperation operation = operations.get(i);
                 results[i] = operation.apply(this, results, i);
             } catch (SQLException e) {
                 Log.w(LOGTAG, "SQLite Exception during applyBatch.", e);
                 // The Android API makes it implementation-defined whether
                 // the failure of a single operation makes all others abort
                 // or not. For our use cases, best-effort operation makes
                 // more sense. Rolling back and forcing the caller to retry
                 // after it figures out what went wrong isn't very convenient
                 // anyway.
                 // Signal failed operation back, so the caller knows what
                 // went through and what didn't.
                 results[i] = new ContentProviderResult(0);
                 failures = true;
                 // http://www.sqlite.org/lang_conflict.html
                 // Note that we need a new transaction, subsequent operations
                 // on this one will fail (we're in ABORT by default, which
                 // isn't IGNORE). We still need to set it as successful to let
                 // everything before the failed op go through.
                 // We can't set conflict resolution on API level < 8, and even
                 // above 8 it requires splitting the call per operation
                 // (insert/update/delete).
                 db.setTransactionSuccessful();
                 db.endTransaction();
                 db.beginTransaction();
             } catch (OperationApplicationException e) {
                 // Repeat of above.
                 results[i] = new ContentProviderResult(0);
                 failures = true;
                 db.setTransactionSuccessful();
                 db.endTransaction();
                 db.beginTransaction();
             }
         }
         trace("Flushing DB applyBatch...");
         markBatchSuccessful(db);
         endBatch(db);
         if (failures) {
             throw new OperationApplicationException();
         }
         return results;
     }
 }

The Tor Browser / annotate

mobile/android/base/db/BrowserProvider.java@fc2d59ddac77 (annotated)

mobile/android/base/db/BrowserProvider.java