Bug 1336909 - Restrict URLCLASSIFIER_PREFIX_MATCH to profiles that have working V4. r=francois

MozReview-Commit-ID: L3lKgiohalH

--HG--
extra : rebase_source : 1ac11242c4db4b129fdb316deee92dd514b65f49

toolkit/components/url-classifier/Classifier.cpp

@@ -452,6 +452,16 @@ Classifier::Check(const nsACString& aSpec,
     }
   }
 
+  // Only record telemetry when both v2 and v4 have data.
+  bool isV2Empty = true, isV4Empty = true;
+  for (auto&& cache : cacheArray) {
+    bool& ref = LookupCache::Cast<LookupCacheV2>(cache) ? isV2Empty : isV4Empty;
+    ref = ref ? cache->IsEmpty() : false;
+    if (!isV2Empty && !isV4Empty) {
+      break;
+    }
+  }
+
   PrefixMatch matchingStatistics = PrefixMatch::eNoMatch;
 
   // Now check each lookup fragment against the entries in the DB.
@@ -506,8 +516,10 @@ Classifier::Check(const nsACString& aSpec,
       }
     }
 
-    Telemetry::Accumulate(Telemetry::URLCLASSIFIER_PREFIX_MATCH,
-                          static_cast<uint8_t>(matchingStatistics));
+    if (!isV2Empty && !isV4Empty) {
+      Telemetry::Accumulate(Telemetry::URLCLASSIFIER_PREFIX_MATCH,
+                            static_cast<uint8_t>(matchingStatistics));
+    }
   }
 
   return NS_OK;

toolkit/components/url-classifier/LookupCache.cpp

@@ -470,6 +470,14 @@ LookupCacheV2::IsHashEntryConfirmed(const Completion& aEntry,
   }
 }
 
+bool
+LookupCacheV2::IsEmpty()
+{
+  bool isEmpty;
+  mPrefixSet->IsEmpty(&isEmpty);
+  return isEmpty;
+}
+
 nsresult
 LookupCacheV2::Build(AddPrefixArray& aAddPrefixes,
                      AddCompleteArray& aAddCompletes)

toolkit/components/url-classifier/LookupCache.h

@@ -148,6 +148,8 @@ public:
                                     uint32_t aFreshnessGuarantee,
                                     bool* aConfirmed) = 0;
 
+  virtual bool IsEmpty() = 0;
+
   virtual void ClearAll();
 
   template<typename T>
@@ -200,6 +202,8 @@ public:
                                     uint32_t aFreshnessGuarantee,
                                     bool* aConfirmed) override;
 
+  virtual bool IsEmpty() override;
+
   nsresult Build(AddPrefixArray& aAddPrefixes,
                  AddCompleteArray& aAddCompletes);
 

toolkit/components/url-classifier/LookupCacheV4.cpp

@@ -117,6 +117,14 @@ LookupCacheV4::IsHashEntryConfirmed(const Completion& aEntry,
   *aConfirmed = true;
 }
 
+bool
+LookupCacheV4::IsEmpty()
+{
+  bool isEmpty;
+  mVLPrefixSet->IsEmpty(&isEmpty);
+  return isEmpty;
+}
+
 nsresult
 LookupCacheV4::Build(PrefixStringMap& aPrefixMap)
 {

toolkit/components/url-classifier/LookupCacheV4.h

@@ -33,6 +33,8 @@ public:
                                     uint32_t aFreshnessGuarantee,
                                     bool* aConfirmed) override;
 
+  virtual bool IsEmpty() override;
+
   nsresult Build(PrefixStringMap& aPrefixMap);
 
   nsresult GetPrefixes(PrefixStringMap& aPrefixMap);