From 250155d0dbc55eacf122a99271126d52b609c306 Mon Sep 17 00:00:00 2001
From: Alex Loiko <aleloi@webrtc.org>
Date: Mon, 26 Mar 2018 14:36:46 +0200
Subject: [PATCH] Fix histogram logging in InterpolatedGainCurve.

We had the following pattern:

if (case_A) metric = METRIC_A;
if (case_B) metric = METRIC_B;
RTC_HISTOGRAM_COUNTS_10000(metric, value);

That's wrong, because once the logging macro runs once, it will use
the same histogram no matter what the first argument is. The macro
expands into roughly

static Histogram* histogram_ptr = nullptr;
if (histogram_ptr == nullptr) {
  // Look up the histogram and put in histogram_ptr
}
// Add data through the histogram pointer.

We change the logging to use macros with string literals. We add a
macro for every of the 4 possible invocations. The macros will expand
to one static pointer each.

Bug: webrtc:8925
Change-Id: Ic7e4a6299eff31dd5988047edfcedce7d369e5ce
Reviewed-on: https://webrtc-review.googlesource.com/64724
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Reviewed-by: Alessio Bazzica <alessiob@webrtc.org>
Commit-Queue: Alex Loiko <aleloi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22606}
---
 .../agc2/interpolated_gain_curve.cc           | 36 +++++++++++++------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/modules/audio_processing/agc2/interpolated_gain_curve.cc b/modules/audio_processing/agc2/interpolated_gain_curve.cc
index aac533d83f..7f1f16cba4 100644
--- a/modules/audio_processing/agc2/interpolated_gain_curve.cc
+++ b/modules/audio_processing/agc2/interpolated_gain_curve.cc
@@ -20,19 +20,33 @@ namespace webrtc {
 namespace {
 void LogRegionStats(const InterpolatedGainCurve::Stats& stats) {
   using Region = InterpolatedGainCurve::GainCurveRegion;
+  const int duration_s =
+      stats.region_duration_frames / (1000 / kFrameDurationMs);
 
-  std::string histogram_name = "WebRTC.Audio.Agc2.FixedDigitalGainCurveRegion.";
-  if (stats.region == Region::kIdentity) {
-    histogram_name += "Identity";
-  } else if (stats.region == Region::kKnee) {
-    histogram_name += "Knee";
-  } else if (stats.region == Region::kLimiter) {
-    histogram_name += "Limiter";
-  } else {
-    histogram_name += "Saturation";
+  switch (stats.region) {
+    case Region::kIdentity: {
+      RTC_HISTOGRAM_COUNTS_10000(
+          "WebRTC.Audio.Agc2.FixedDigitalGainCurveRegion.Identity", duration_s);
+      break;
+    }
+    case Region::kKnee: {
+      RTC_HISTOGRAM_COUNTS_10000(
+          "WebRTC.Audio.Agc2.FixedDigitalGainCurveRegion.Knee", duration_s);
+      break;
+    }
+    case Region::kLimiter: {
+      RTC_HISTOGRAM_COUNTS_10000(
+          "WebRTC.Audio.Agc2.FixedDigitalGainCurveRegion.Limiter", duration_s);
+      break;
+    }
+    case Region::kSaturation: {
+      RTC_HISTOGRAM_COUNTS_10000(
+          "WebRTC.Audio.Agc2.FixedDigitalGainCurveRegion.Saturation",
+          duration_s);
+      break;
+    }
+    default: { RTC_NOTREACHED(); }
   }
-  RTC_HISTOGRAM_COUNTS_10000(histogram_name,
-                             stats.region_duration_frames / 100);
 }
 }  // namespace