michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko;
michael@0: 
michael@0: import org.mozilla.gecko.db.BrowserDB;
michael@0: import org.mozilla.gecko.util.ThreadUtils;
michael@0: 
michael@0: import android.database.Cursor;
michael@0: import android.net.Uri;
michael@0: import android.os.Handler;
michael@0: import android.util.Log;
michael@0: 
michael@0: import java.lang.ref.SoftReference;
michael@0: import java.util.HashSet;
michael@0: import java.util.LinkedList;
michael@0: import java.util.Queue;
michael@0: import java.util.Set;
michael@0: 
michael@0: class GlobalHistory {
michael@0:     private static final String LOGTAG = "GeckoGlobalHistory";
michael@0: 
michael@0:     private static GlobalHistory sInstance = new GlobalHistory();
michael@0: 
michael@0:     static GlobalHistory getInstance() {
michael@0:         return sInstance;
michael@0:     }
michael@0: 
michael@0:     // this is the delay between receiving a URI check request and processing it.
michael@0:     // this allows batching together multiple requests and processing them together,
michael@0:     // which is more efficient.
michael@0:     private static final long BATCHING_DELAY_MS = 100;
michael@0: 
michael@0:     private final Handler mHandler;                     // a background thread on which we can process requests
michael@0:     private final Queue<String> mPendingUris;           // URIs that need to be checked
michael@0:     private SoftReference<Set<String>> mVisitedCache;   // cache of the visited URI list
michael@0:     private final Runnable mNotifierRunnable;           // off-thread runnable used to check URIs
michael@0:     private boolean mProcessing; // = false             // whether or not the runnable is queued/working
michael@0: 
michael@0:     private GlobalHistory() {
michael@0:         mHandler = ThreadUtils.getBackgroundHandler();
michael@0:         mPendingUris = new LinkedList<String>();
michael@0:         mVisitedCache = new SoftReference<Set<String>>(null);
michael@0:         mNotifierRunnable = new Runnable() {
michael@0:             @Override
michael@0:             public void run() {
michael@0:                 Set<String> visitedSet = mVisitedCache.get();
michael@0:                 if (visitedSet == null) {
michael@0:                     // the cache was wiped away, repopulate it
michael@0:                     Log.w(LOGTAG, "Rebuilding visited link set...");
michael@0:                     visitedSet = new HashSet<String>();
michael@0:                     Cursor c = null;
michael@0:                     try {
michael@0:                         c = BrowserDB.getAllVisitedHistory(GeckoAppShell.getContext().getContentResolver());
michael@0:                         if (c == null) {
michael@0:                             return;
michael@0:                         }
michael@0: 
michael@0:                         if (c.moveToFirst()) {
michael@0:                             do {
michael@0:                                 visitedSet.add(c.getString(0));
michael@0:                             } while (c.moveToNext());
michael@0:                         }
michael@0:                         mVisitedCache = new SoftReference<Set<String>>(visitedSet);
michael@0:                     } finally {
michael@0:                         if (c != null)
michael@0:                             c.close();
michael@0:                     }
michael@0:                 }
michael@0: 
michael@0:                 // this runs on the same handler thread as the checkUriVisited code,
michael@0:                 // so no synchronization needed
michael@0:                 while (true) {
michael@0:                     String uri = mPendingUris.poll();
michael@0:                     if (uri == null) {
michael@0:                         break;
michael@0:                     }
michael@0:                     if (visitedSet.contains(uri)) {
michael@0:                         GeckoAppShell.notifyUriVisited(uri);
michael@0:                     }
michael@0:                 }
michael@0:                 mProcessing = false;
michael@0:             }
michael@0:         };
michael@0:     }
michael@0: 
michael@0:     public void addToGeckoOnly(String uri) {
michael@0:         Set<String> visitedSet = mVisitedCache.get();
michael@0:         if (visitedSet != null) {
michael@0:             visitedSet.add(uri);
michael@0:         }
michael@0:         GeckoAppShell.notifyUriVisited(uri);
michael@0:     }
michael@0: 
michael@0:     public void add(String uri) {
michael@0:         BrowserDB.updateVisitedHistory(GeckoAppShell.getContext().getContentResolver(), uri);
michael@0:         addToGeckoOnly(uri);
michael@0:     }
michael@0: 
michael@0:     public void update(String uri, String title) {
michael@0:         BrowserDB.updateHistoryTitle(GeckoAppShell.getContext().getContentResolver(), uri, title);
michael@0:     }
michael@0: 
michael@0:     public void checkUriVisited(final String uri) {
michael@0:         mHandler.post(new Runnable() {
michael@0:             @Override
michael@0:             public void run() {
michael@0:                 // this runs on the same handler thread as the processing loop,
michael@0:                 // so no synchronization needed
michael@0:                 mPendingUris.add(uri);
michael@0:                 if (mProcessing) {
michael@0:                     // there's already a runnable queued up or working away, so
michael@0:                     // no need to post another
michael@0:                     return;
michael@0:                 }
michael@0:                 mProcessing = true;
michael@0:                 mHandler.postDelayed(mNotifierRunnable, BATCHING_DELAY_MS);
michael@0:             }
michael@0:         });
michael@0:     }
michael@0: }