From 040b79ff7e4d5824a97ead0099d7ea84c2476c30 Mon Sep 17 00:00:00 2001
From: asapersson <asapersson@webrtc.org>
Date: Tue, 2 Feb 2016 07:13:01 -0800
Subject: [PATCH] Add helper macros for calling a histogram with different
 names.

To be used when a metric is used in different modes such as real-time vs screenshare (will be done in https://codereview.webrtc.org/1564923008/).

BUG=webrtc:5283

Review URL: https://codereview.webrtc.org/1567013004

Cr-Commit-Position: refs/heads/master@{#11461}
---
 webrtc/system_wrappers/include/metrics.h      | 52 +++++++++++++++++++
 .../source/metrics_unittest.cc                | 24 +++++++++
 2 files changed, 76 insertions(+)

diff --git a/webrtc/system_wrappers/include/metrics.h b/webrtc/system_wrappers/include/metrics.h
index 4cd74c5e84..ce193bdc39 100644
--- a/webrtc/system_wrappers/include/metrics.h
+++ b/webrtc/system_wrappers/include/metrics.h
@@ -153,6 +153,58 @@
     webrtc::metrics::HistogramAdd(histogram_pointer, name, sample); \
   } while (0)
 
+
+// Helper macros.
+// Macros for calling a histogram with varying name (e.g. when using a metric
+// in different modes such as real-time vs screenshare).
+#define RTC_HISTOGRAMS_COUNTS_100(index, name, sample) \
+  RTC_HISTOGRAMS_COMMON(index, name, sample, \
+      RTC_HISTOGRAM_COUNTS(name, sample, 1, 100, 50))
+
+#define RTC_HISTOGRAMS_COUNTS_200(index, name, sample) \
+  RTC_HISTOGRAMS_COMMON(index, name, sample, \
+      RTC_HISTOGRAM_COUNTS(name, sample, 1, 200, 50))
+
+#define RTC_HISTOGRAMS_COUNTS_1000(index, name, sample) \
+  RTC_HISTOGRAMS_COMMON(index, name, sample, \
+      RTC_HISTOGRAM_COUNTS(name, sample, 1, 1000, 50))
+
+#define RTC_HISTOGRAMS_COUNTS_10000(index, name, sample) \
+  RTC_HISTOGRAMS_COMMON(index, name, sample, \
+      RTC_HISTOGRAM_COUNTS(name, sample, 1, 10000, 50))
+
+#define RTC_HISTOGRAMS_COUNTS_100000(index, name, sample) \
+  RTC_HISTOGRAMS_COMMON(index, name, sample, \
+      RTC_HISTOGRAM_COUNTS(name, sample, 1, 100000, 50))
+
+#define RTC_HISTOGRAMS_ENUMERATION(index, name, sample, boundary) \
+  RTC_HISTOGRAMS_COMMON(index, name, sample, \
+      RTC_HISTOGRAM_ENUMERATION(name, sample, boundary))
+
+#define RTC_HISTOGRAMS_PERCENTAGE(index, name, sample) \
+  RTC_HISTOGRAMS_COMMON(index, name, sample, \
+      RTC_HISTOGRAM_PERCENTAGE(name, sample))
+
+#define RTC_HISTOGRAMS_COMMON(index, name, sample, macro_invocation) \
+  do { \
+    RTC_DCHECK(index >= 0); \
+    RTC_DCHECK(index <= 2); \
+    switch (index) { \
+      case 0: \
+        macro_invocation; \
+        break; \
+      case 1: \
+        macro_invocation; \
+        break; \
+      case 2: \
+        macro_invocation; \
+        break; \
+      default: \
+        RTC_NOTREACHED(); \
+    } \
+  } while (0)
+
+
 namespace webrtc {
 namespace metrics {
 
diff --git a/webrtc/system_wrappers/source/metrics_unittest.cc b/webrtc/system_wrappers/source/metrics_unittest.cc
index 8319b78ee0..7de6f5e6ee 100644
--- a/webrtc/system_wrappers/source/metrics_unittest.cc
+++ b/webrtc/system_wrappers/source/metrics_unittest.cc
@@ -21,6 +21,9 @@ const std::string kName = "Name";
 void AddSparseSample(const std::string& name, int sample) {
   RTC_HISTOGRAM_COUNTS_SPARSE_100(name, sample);
 }
+void AddSampleWithVaryingName(int index, const std::string& name, int sample) {
+  RTC_HISTOGRAMS_COUNTS_100(index, name, sample);
+}
 #if GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
 void AddSample(const std::string& name, int sample) {
   RTC_HISTOGRAM_COUNTS_100(name, sample);
@@ -72,6 +75,27 @@ TEST(MetricsTest, RtcHistogramCounts_AddMultipleSamples) {
   EXPECT_EQ(kNumSamples - 1, test::LastHistogramSample(kName));
 }
 
+TEST(MetricsTest, RtcHistogramsCounts_AddSample) {
+  test::ClearHistograms();
+  AddSampleWithVaryingName(0, "Name1", kSample);
+  AddSampleWithVaryingName(1, "Name2", kSample + 1);
+  AddSampleWithVaryingName(2, "Name3", kSample + 2);
+  EXPECT_EQ(1, test::NumHistogramSamples("Name1"));
+  EXPECT_EQ(1, test::NumHistogramSamples("Name2"));
+  EXPECT_EQ(1, test::NumHistogramSamples("Name3"));
+  EXPECT_EQ(kSample + 0, test::LastHistogramSample("Name1"));
+  EXPECT_EQ(kSample + 1, test::LastHistogramSample("Name2"));
+  EXPECT_EQ(kSample + 2, test::LastHistogramSample("Name3"));
+}
+
+#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
+TEST(MetricsTest, RtcHistogramsCounts_InvalidIndex) {
+  EXPECT_DEATH(RTC_HISTOGRAMS_COUNTS_1000(-1, kName, kSample), "");
+  EXPECT_DEATH(RTC_HISTOGRAMS_COUNTS_1000(3, kName, kSample), "");
+  EXPECT_DEATH(RTC_HISTOGRAMS_COUNTS_1000(3u, kName, kSample), "");
+}
+#endif
+
 TEST(MetricsTest, RtcHistogramSparse_NonConstantNameWorks) {
   test::ClearHistograms();
   AddSparseSample("Name1", kSample);