Bug 1096785 - Add Telemetry::Accumulate() for keyed histograms. r=froydnj

toolkit/components/telemetry/Telemetry.cpp

@@ -622,6 +622,7 @@ public:
                  uint32_t histogramType, uint32_t min, uint32_t max,
                  uint32_t bucketCount);
   nsresult GetHistogram(const nsCString& name, Histogram** histogram);
+  Histogram* GetHistogram(const nsCString& name);
   uint32_t GetHistogramType() const { return mHistogramType; }
   nsresult GetJSKeys(JSContext* cx, JS::CallArgs& args);
   nsresult GetJSSnapshot(JSContext* cx, JS::Handle<JSObject*> obj);
@@ -699,6 +700,16 @@ KeyedHistogram::GetHistogram(const nsCString& key, Histogram** histogram)
   return NS_OK;
 }
 
+Histogram*
+KeyedHistogram::GetHistogram(const nsCString& key)
+{
+  Histogram* h = nullptr;
+  if (NS_FAILED(GetHistogram(key, &h))) {
+    return nullptr;
+  }
+  return h;
+}
+
 /* static */
 PLDHashOperator
 KeyedHistogram::ClearHistogramEnumerator(KeyedHistogramEntry* entry, void*)
@@ -820,6 +831,8 @@ public:
   };
   typedef nsBaseHashtableET<nsCStringHashKey, StmtStats> SlowSQLEntryType;
 
+  static KeyedHistogram* GetKeyedHistogramById(const nsACString &id);
+
 private:
   TelemetryImpl();
   ~TelemetryImpl();
@@ -2932,6 +2945,19 @@ TelemetryImpl::GetKeyedHistogramById(const nsACString &name, JSContext *cx,
   return WrapAndReturnKeyedHistogram(keyed, cx, ret);
 }
 
+/* static */
+KeyedHistogram*
+TelemetryImpl::GetKeyedHistogramById(const nsACString &name)
+{
+  if (!sTelemetry) {
+    return nullptr;
+  }
+
+  KeyedHistogram* keyed = nullptr;
+  sTelemetry->mKeyedHistograms.Get(name, &keyed);
+  return keyed;
+}
+
 NS_IMETHODIMP
 TelemetryImpl::GetCanRecord(bool *ret) {
   *ret = mCanRecord;
@@ -3373,6 +3399,23 @@ Accumulate(ID aHistogram, uint32_t aSample)
     h->Add(aSample);
 }
 
+void
+Accumulate(ID aID, const nsCString& aKey, uint32_t aSample)
+{
+  if (!TelemetryImpl::CanRecord()) {
+    return;
+  }
+
+  const TelemetryHistogram& th = gHistograms[aID];
+  KeyedHistogram* keyed = TelemetryImpl::GetKeyedHistogramById(nsDependentCString(th.id()));
+  MOZ_ASSERT(keyed);
+
+  Histogram* histogram = keyed->GetHistogram(aKey);
+  if (histogram) {
+    histogram->Add(aSample);
+  }
+}
+
 void
 Accumulate(const char* name, uint32_t sample)
 {

toolkit/components/telemetry/Telemetry.h

@@ -42,6 +42,15 @@ void Init();
  */
 void Accumulate(ID id, uint32_t sample);
 
+/**
+ * Adds sample to a keyed histogram defined in TelemetryHistograms.h
+ *
+ * @param id - keyed histogram id
+ * @param key - the string key
+ * @param sample - (optional) value to record, defaults to 1.
+ */
+void Accumulate(ID id, const nsCString& key, uint32_t sample = 1);
+
 /**
  * Adds a sample to a histogram defined in TelemetryHistograms.h.
  * This function is here to support telemetry measurements from Java,