Issue 6299 - Avoid main thread lock on URL loading

libadblockplus-android-webview/src/org/adblockplus/libadblockplus/android/webview/AdblockWebView.java

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 87 matching lines @@
   private boolean adblockEnabled = true;
   private boolean debugMode;
   private AdblockEngineProvider provider;
   private Integer loadError;
   private int allowDrawDelay = ALLOW_DRAW_DELAY;
   private WebChromeClient extWebChromeClient;
   private WebViewClient extWebViewClient;
   private WebViewClient intWebViewClient;
   private Map<String, String> url2Referrer = Collections.synchronizedMap(new HashMap<String, String>());
   private String url;
-  private String domain;
   private String injectJs;
   private CountDownLatch elemHideLatch;
   private String elemHideSelectorsString;
   private Object elemHideThreadLockObject = new Object();
   private ElemHideThread elemHideThread;
   private boolean loading;
   private volatile boolean elementsHidden = false;
   private final Handler handler = new Handler();
 
   // used to prevent user see flickering for elements to hide
@@ skipping 701 matching lines @@
       boolean isXmlHttpRequest, String[] referrerChainArray)
     {
       // if dispose() was invoke, but the page is still loading then just let it go
       if (provider.getCounter() == 0)
       {
         e("FilterEngine already disposed, allow loading");
 
         // allow loading by returning null
         return null;
       }
+      else
+      {
+        provider.waitForReady();
+      }
 
       if (isMainFrame)
       {
         // never blocking main frame requests, just subrequests
         w(url + " is main frame, allow loading");
 
         // allow loading by returning null
         return null;
       }
 
@@ skipping 130 matching lines @@
     {
       try
       {
         if (provider.getCounter() == 0)
         {
           w("FilterEngine already disposed");
           selectorsString = EMPTY_ELEMHIDE_ARRAY_STRING;
         }
         else
         {
+          provider.waitForReady();
           String[] referrers = new String[]
             {
               url
             };
 
           List<Subscription> subscriptions = provider
             .getEngine()
             .getFilterEngine()
             .getListedSubscriptions();
 
@@ skipping 11 matching lines @@
             }
           }
           finally
           {
             for (Subscription eachSubscription : subscriptions)
             {
               eachSubscription.dispose();
             }
           }
 
-          d("Requesting elemhide selectors from AdblockEngine for " + url + " in " + this);
-          List<String> selectors = provider
-            .getEngine()
-            .getElementHidingSelectors(url, domain, referrers);
+          String domain = provider.getEngine().getFilterEngine().getHostFromURL(url);
+          if (domain == null)

[anton, 2018/01/23 06:14:10]

Not sure if it can happen

+          {
+            e("Failed to extract domain from " + url);
+            selectorsString = EMPTY_ELEMHIDE_ARRAY_STRING;
+          }
+          else
+          {
+            d("Requesting elemhide selectors from AdblockEngine for " + url + " in " + this);
+            List<String> selectors = provider
+              .getEngine()
+              .getElementHidingSelectors(url, domain, referrers);
 
-          d("Finished requesting elemhide selectors, got " + selectors.size() + " in " + this);
-          selectorsString = Utils.stringListToJsonArray(selectors);
+            d("Finished requesting elemhide selectors, got " + selectors.size() + " in " + this);
+            selectorsString = Utils.stringListToJsonArray(selectors);
+          }
         }
       }
       finally
       {
         if (isCancelled.get())
         {
           w("This thread is cancelled, exiting silently " + this);
         }
         else
         {
@@ skipping 84 matching lines @@
     d("Start loading " + newUrl);
 
     loading = true;
     addDomListener = true;
     elementsHidden = false;
     loadError = null;
     url = newUrl;
 
     if (url != null)
     {
-      try
-      {
-        d("Waiting for adblock engine");
-        provider.waitForReady();
-
-        domain = provider.getEngine().getFilterEngine().getHostFromURL(url);
-        if (domain == null)
-        {
-          throw new RuntimeException("Failed to extract domain from " + url);
-        }
-
-        d("Extracted domain " + domain + " from " + url);
-      }
-      catch (Throwable t)
-      {
-        e("Failed to extract domain from " + url, t);
-      }
-
       elemHideLatch = new CountDownLatch(1);
       elemHideThread = new ElemHideThread(elemHideLatch);
       elemHideThread.setFinishedRunnable(elemHideThreadFinishedRunnable);
       elemHideThread.start();
     }
     else
     {
       elemHideLatch = null;
     }
   }
@@ skipping 287 matching lines @@
         w("Busy with elemhide selectors, delayed disposing scheduled");
         elemHideThread.setFinishedRunnable(disposeRunnable);
       }
       else
       {
         disposeRunnable.run();
       }
     }
   }
 }