system_wrappers: rename interface -> include

webrtc/system_wrappers/interface/metrics.h

-//
-// Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
-//
-// Use of this source code is governed by a BSD-style license
-// that can be found in the LICENSE file in the root of the source
-// tree. An additional intellectual property rights grant can be found
-// in the file PATENTS.  All contributing project authors may
-// be found in the AUTHORS file in the root of the source tree.
-//
-
-#ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_METRICS_H_
-#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_METRICS_H_
-
-#include <string>
-
-#include "webrtc/common_types.h"
-
-// Macros for allowing WebRTC clients (e.g. Chrome) to gather and aggregate
-// statistics.
-//
-// Histogram for counters.
-// RTC_HISTOGRAM_COUNTS(name, sample, min, max, bucket_count);
-//
-// Histogram for enumerators.
-// The boundary should be above the max enumerator sample.
-// RTC_HISTOGRAM_ENUMERATION(name, sample, boundary);
-//
-//
-// The macros use the methods HistogramFactoryGetCounts,
-// HistogramFactoryGetEnumeration and HistogramAdd.
-//
-// Therefore, WebRTC clients must either:
-//
-// - provide implementations of
-//   Histogram* webrtc::metrics::HistogramFactoryGetCounts(
-//       const std::string& name, int sample, int min, int max,
-//       int bucket_count);
-//   Histogram* webrtc::metrics::HistogramFactoryGetEnumeration(
-//       const std::string& name, int sample, int boundary);
-//   void webrtc::metrics::HistogramAdd(
-//       Histogram* histogram_pointer, const std::string& name, int sample);
-//
-// - or link with the default implementations (i.e.
-//   system_wrappers/system_wrappers.gyp:metrics_default).
-//
-//
-// Example usage:
-//
-// RTC_HISTOGRAM_COUNTS("WebRTC.Video.NacksSent", nacks_sent, 1, 100000, 100);
-//
-// enum Types {
-//   kTypeX,
-//   kTypeY,
-//   kBoundary,
-// };
-//
-// RTC_HISTOGRAM_ENUMERATION("WebRTC.Types", kTypeX, kBoundary);
-
-
-// Macros for adding samples to a named histogram.
-//
-// NOTE: this is a temporary solution.
-// The aim is to mimic the behaviour in Chromium's src/base/metrics/histograms.h
-// However as atomics are not supported in webrtc, this is for now a modified
-// and temporary solution. Note that the histogram is constructed/found for
-// each call. Therefore, for now only use this implementation for metrics
-// that do not need to be updated frequently.
-// TODO(asapersson): Change implementation when atomics are supported.
-// Also consider changing string to const char* when switching to atomics.
-
-// Histogram for counters.
-#define RTC_HISTOGRAM_COUNTS_100(name, sample) RTC_HISTOGRAM_COUNTS( \
-    name, sample, 1, 100, 50)
-
-#define RTC_HISTOGRAM_COUNTS_200(name, sample) RTC_HISTOGRAM_COUNTS( \
-    name, sample, 1, 200, 50)
-
-#define RTC_HISTOGRAM_COUNTS_1000(name, sample) RTC_HISTOGRAM_COUNTS( \
-    name, sample, 1, 1000, 50)
-
-#define RTC_HISTOGRAM_COUNTS_10000(name, sample) RTC_HISTOGRAM_COUNTS( \
-    name, sample, 1, 10000, 50)
-
-#define RTC_HISTOGRAM_COUNTS_100000(name, sample) RTC_HISTOGRAM_COUNTS( \
-    name, sample, 1, 100000, 50)
-
-#define RTC_HISTOGRAM_COUNTS(name, sample, min, max, bucket_count) \
-    RTC_HISTOGRAM_COMMON_BLOCK(name, sample, \
-        webrtc::metrics::HistogramFactoryGetCounts( \
-            name, min, max, bucket_count))
-
-// Histogram for percentage.
-#define RTC_HISTOGRAM_PERCENTAGE(name, sample) \
-    RTC_HISTOGRAM_ENUMERATION(name, sample, 101)
-
-// Histogram for enumerators.
-// |boundary| should be above the max enumerator sample.
-#define RTC_HISTOGRAM_ENUMERATION(name, sample, boundary) \
-    RTC_HISTOGRAM_COMMON_BLOCK(name, sample, \
-        webrtc::metrics::HistogramFactoryGetEnumeration(name, boundary))
-
-#define RTC_HISTOGRAM_COMMON_BLOCK(constant_name, sample, \
-                                   factory_get_invocation) \
-  do { \
-    webrtc::metrics::Histogram* histogram_pointer = factory_get_invocation; \
-    webrtc::metrics::HistogramAdd(histogram_pointer, constant_name, sample); \
-  } while (0)
-
-
-namespace webrtc {
-namespace metrics {
-
-// Time that should have elapsed for stats that are gathered once per call.
-enum { kMinRunTimeInSeconds = 10 };
-
-class Histogram;
-
-// Functions for getting pointer to histogram (constructs or finds the named
-// histogram).
-
-// Get histogram for counters.
-Histogram* HistogramFactoryGetCounts(
-    const std::string& name, int min, int max, int bucket_count);
-
-// Get histogram for enumerators.
-// |boundary| should be above the max enumerator sample.
-Histogram* HistogramFactoryGetEnumeration(
-    const std::string& name, int boundary);
-
-// Function for adding a |sample| to a histogram.
-// |name| can be used to verify that it matches the histogram name.
-void HistogramAdd(
-    Histogram* histogram_pointer, const std::string& name, int sample);
-
-}  // namespace metrics
-}  // namespace webrtc
-
-#endif  // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_METRICS_H_
-