Move referrer mapping to a dedicated class

src/org/adblockplus/android/AdblockPlus.java

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 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 75 matching lines @@
   private Subscription[] subscriptions;
   /**
    * Indicates whether filtering is enabled or not.
    */
   private boolean filteringEnabled = false;
 
   private ABPEngine abpEngine;
 
   private static AdblockPlus instance;
 
-  private static class ReferrerMappingCache extends LinkedHashMap<String, String>
-  {
-    private static final long serialVersionUID = 1L;
-    private static final int MAX_SIZE = 5000;
-
-    public ReferrerMappingCache()
-    {
-      super(MAX_SIZE + 1, 0.75f, true);
-    }
-
-    @Override
-    protected boolean removeEldestEntry(final Map.Entry<String, String> eldest)
-    {
-      return size() > MAX_SIZE;
-    }
-  };
-
-  private final ReferrerMappingCache referrerMapping = new ReferrerMappingCache();
+  private final ReferrerMapping referrerMapping = new ReferrerMapping();
 
   /**
    * Returns pointer to itself (singleton pattern).
    */
   public static AdblockPlus getApplication()
   {
     return instance;
   }
 
   public int getBuildNumber()
@@ skipping 228 matching lines @@
    *          Request referrer header
    * @param accept
    *          Request accept header
    * @return true if matched filter was found
    * @throws Exception
    */
   public boolean matches(final String url, final String query, final String referrer, final String accept)
   {
     final String fullUrl = !"".equals(query) ? url + "?" + query : url;
     if (referrer != null)
-      referrerMapping.put(fullUrl, referrer);
+      referrerMapping.add(fullUrl, referrer);
 
     if (!filteringEnabled)
       return false;
 
     String contentType = null;
 
     if (accept != null)
     {
       if (accept.contains("text/css"))
         contentType = "STYLESHEET";
@@ skipping 12 matching lines @@
       else if (RE_IMAGE.matcher(url).find())
         contentType = "IMAGE";
       else if (RE_FONT.matcher(url).find())
         contentType = "FONT";
       else if (RE_HTML.matcher(url).find())
         contentType = "SUBDOCUMENT";
     }
     if (contentType == null)
       contentType = "OTHER";
 
-    final List<String> referrerChain = buildReferrerChain(referrer);
+    final List<String> referrerChain = referrerMapping.buildReferrerChain(referrer);
     Log.d("Referrer chain", fullUrl + ": " + referrerChain.toString());
     final String[] referrerChainArray = referrerChain.toArray(new String[referrerChain.size()]);
     return abpEngine.matches(fullUrl, contentType, referrerChainArray);
   }
 
-  private List<String> buildReferrerChain(String url)
-  {
-    final List<String> referrerChain = new ArrayList<String>();
-    // We need to limit the chain length to ensure we don't block indefinitely if there's
-    // a referrer loop.
-    final int maxChainLength = 10;
-    for (int i = 0; i < maxChainLength && url != null; i++)
-    {
-      referrerChain.add(0, url);
-      url = referrerMapping.get(url);
-    }
-    return referrerChain;
-  }
-
   /**
    * Checks if filtering is enabled.
    */
   public boolean isFilteringEnabled()
   {
     return filteringEnabled;
   }
 
   /**
    * Enables or disables filtering.
@@ skipping 111 matching lines @@
       Log.e(TAG, e.getMessage(), e);
     }
 
     // Set crash handler
     Thread.setDefaultUncaughtExceptionHandler(new CrashHandler(this));
 
     // Initiate update check
     scheduleUpdater(0);
   }
 }