Bug 1164518 - Avoid unnecessary DB updates when caching Safe Browsing results. r=gcp

MozReview-Commit-ID: HYNaTdCRohL

--HG--
extra : rebase_source : 681b33066b21719296c9d33f8d71a72335513188

toolkit/components/url-classifier/Entries.h

@@ -181,6 +181,13 @@ struct AddComplete {
     }
     return addChunk - other.addChunk;
   }
+
+  bool operator!=(const AddComplete& aOther) const {
+    if (addChunk != aOther.addChunk) {
+      return true;
+    }
+    return complete != aOther.complete;
+  }
 };
 
 struct SubPrefix {

toolkit/components/url-classifier/LookupCache.h

@@ -67,6 +67,13 @@ typedef nsTArray<LookupResult> LookupResultArray;
 struct CacheResult {
   AddComplete entry;
   nsCString table;
+
+  bool operator==(const CacheResult& aOther) const {
+    if (entry != aOther.entry) {
+      return false;
+    }
+    return table == aOther.table;
+  }
 };
 typedef nsTArray<CacheResult> CacheResultArray;
 

toolkit/components/url-classifier/nsIUrlClassifierDBService.idl

@@ -107,6 +107,11 @@ interface nsIUrlClassifierDBService : nsISupports
   void setLastUpdateTime(in ACString tableName,
                          in unsigned long long lastUpdateTime);
 
+  /**
+   * Forget the results that were used in the last DB update.
+   */
+  void clearLastResults();
+
   ////////////////////////////////////////////////////////////////////////////
   // Incremental update methods.
   //

toolkit/components/url-classifier/nsUrlClassifierDBService.cpp

@@ -660,6 +660,11 @@ nsUrlClassifierDBServiceWorker::CacheCompletions(CacheResultArray *results)
   // Ownership is transferred in to us
   nsAutoPtr<CacheResultArray> resultsPtr(results);
 
+  if (mLastResults == *resultsPtr) {
+    LOG(("Skipping completions that have just been cached already."));
+    return NS_OK;
+  }
+
   nsAutoPtr<ProtocolParser> pParse(new ProtocolParser());
   nsTArray<TableUpdate*> updates;
 
@@ -702,6 +707,7 @@ nsUrlClassifierDBServiceWorker::CacheCompletions(CacheResultArray *results)
    }
 
   mClassifier->ApplyUpdates(&updates);
+  mLastResults = *resultsPtr;
   return NS_OK;
 }
 
@@ -758,6 +764,15 @@ nsUrlClassifierDBServiceWorker::SetLastUpdateTime(const nsACString &table,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsUrlClassifierDBServiceWorker::ClearLastResults()
+{
+  MOZ_ASSERT(!NS_IsMainThread(), "Must be on the background thread");
+  mLastResults.Clear();
+  return NS_OK;
+}
+
+
 // -------------------------------------------------------------------------
 // nsUrlClassifierLookupCallback
 //
@@ -1458,7 +1473,7 @@ nsUrlClassifierDBService::SetHashCompleter(const nsACString &tableName,
   } else {
     mCompleters.Remove(tableName);
   }
-
+  ClearLastResults();
   return NS_OK;
 }
 
@@ -1471,6 +1486,14 @@ nsUrlClassifierDBService::SetLastUpdateTime(const nsACString &tableName,
   return mWorkerProxy->SetLastUpdateTime(tableName, lastUpdateTime);
 }
 
+NS_IMETHODIMP
+nsUrlClassifierDBService::ClearLastResults()
+{
+  NS_ENSURE_TRUE(gDbBackgroundThread, NS_ERROR_NOT_INITIALIZED);
+
+  return mWorkerProxy->ClearLastResults();
+}
+
 NS_IMETHODIMP
 nsUrlClassifierDBService::BeginUpdate(nsIUrlClassifierUpdateObserver *observer,
                                       const nsACString &updateTables)

toolkit/components/url-classifier/nsUrlClassifierDBService.h

@@ -212,6 +212,9 @@ private:
   // the next update
   PrefixArray mMissCache;
 
+  // Stores the last results that triggered a table update.
+  CacheResultArray mLastResults;
+
   nsresult mUpdateStatus;
   nsTArray<nsCString> mUpdateTables;
 

toolkit/components/url-classifier/nsUrlClassifierProxies.cpp

@@ -232,6 +232,19 @@ UrlClassifierDBServiceWorkerProxy::SetLastUpdateTimeRunnable::Run()
   return NS_OK;
 }
 
+NS_IMETHODIMP
+UrlClassifierDBServiceWorkerProxy::ClearLastResults()
+{
+  nsCOMPtr<nsIRunnable> r = new ClearLastResultsRunnable(mTarget);
+  return DispatchToWorkerThread(r);
+}
+
+NS_IMETHODIMP
+UrlClassifierDBServiceWorkerProxy::ClearLastResultsRunnable::Run()
+{
+  return mTarget->ClearLastResults();
+}
+
 NS_IMPL_ISUPPORTS(UrlClassifierLookupCallbackProxy,
                   nsIUrlClassifierLookupCallback)
 

toolkit/components/url-classifier/nsUrlClassifierProxies.h

@@ -191,6 +191,18 @@ public:
     uint64_t mUpdateTime;
   };
 
+  class ClearLastResultsRunnable : public nsRunnable
+  {
+  public:
+    explicit ClearLastResultsRunnable(nsUrlClassifierDBServiceWorker* aTarget)
+      : mTarget(aTarget)
+    { }
+
+    NS_DECL_NSIRUNNABLE
+  private:
+    RefPtr<nsUrlClassifierDBServiceWorker> mTarget;
+  };
+
 public:
   nsresult DoLocalLookup(const nsACString& spec,
                          const nsACString& tables,