base/metrics/stats_counters.cc

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/metrics/stats_counters.h"
   6
   7 namespace base {
   8
   9 StatsCounter::StatsCounter(const std::string& name)
  10     : counter_id_(-1) {
  11   // We prepend the name with 'c:' to indicate that it is a counter.
  12   if (StatsTable::current()) {
  13     // TODO(mbelshe): name_ construction is racy and it may corrupt memory for
  14     // static.
  15     name_ = "c:";
  16     name_.append(name);
  17   }
  18 }
  19
  20 StatsCounter::~StatsCounter() {
  21 }
  22
  23 void StatsCounter::Set(int value) {
  24   int* loc = GetPtr();
  25   if (loc)
  26     *loc = value;
  27 }
  28
  29 void StatsCounter::Add(int value) {
  30   int* loc = GetPtr();
  31   if (loc)
  32     (*loc) += value;
  33 }
  34
  35 StatsCounter::StatsCounter()
  36     : counter_id_(-1) {
  37 }
  38
  39 int* StatsCounter::GetPtr() {
  40   StatsTable* table = StatsTable::current();
  41   if (!table)
  42     return NULL;
  43
  44   // If counter_id_ is -1, then we haven't looked it up yet.
  45   if (counter_id_ == -1) {
  46     counter_id_ = table->FindCounter(name_);
  47     if (table->GetSlot() == 0) {
  48       if (!table->RegisterThread(std::string())) {
  49         // There is no room for this thread.  This thread
  50         // cannot use counters.
  51         counter_id_ = 0;
  52         return NULL;
  53       }
  54     }
  55   }
  56
  57   // If counter_id_ is > 0, then we have a valid counter.
  58   if (counter_id_ > 0)
  59     return table->GetLocation(counter_id_, table->GetSlot());
  60
  61   // counter_id_ was zero, which means the table is full.
  62   return NULL;
  63 }
  64
  65
  66 StatsCounterTimer::StatsCounterTimer(const std::string& name) {
  67   // we prepend the name with 't:' to indicate that it is a timer.
  68   if (StatsTable::current()) {
  69     // TODO(mbelshe): name_ construction is racy and it may corrupt memory for
  70     // static.
  71     name_ = "t:";
  72     name_.append(name);
  73   }
  74 }
  75
  76 StatsCounterTimer::~StatsCounterTimer() {
  77 }
  78
  79 void StatsCounterTimer::Start() {
  80   if (!Enabled())
  81     return;
  82   start_time_ = TimeTicks::Now();
  83   stop_time_ = TimeTicks();
  84 }
  85
  86 // Stop the timer and record the results.
  87 void StatsCounterTimer::Stop() {
  88   if (!Enabled() || !Running())
  89     return;
  90   stop_time_ = TimeTicks::Now();
  91   Record();
  92 }
  93
  94 // Returns true if the timer is running.
  95 bool StatsCounterTimer::Running() {
  96   return Enabled() && !start_time_.is_null() && stop_time_.is_null();
  97 }
  98
  99 // Accept a TimeDelta to increment.
 100 void StatsCounterTimer::AddTime(TimeDelta time) {
 101   Add(static_cast<int>(time.InMilliseconds()));
 102 }
 103
 104 void StatsCounterTimer::Record() {
 105   AddTime(stop_time_ - start_time_);
 106 }
 107
 108
 109 StatsRate::StatsRate(const std::string& name)
 110     : StatsCounterTimer(name),
 111       counter_(name),
 112       largest_add_(std::string(" ").append(name).append("MAX")) {
 113 }
 114
 115 StatsRate::~StatsRate() {
 116 }
 117
 118 void StatsRate::Add(int value) {
 119   counter_.Increment();
 120   StatsCounterTimer::Add(value);
 121   if (value > largest_add_.value())
 122     largest_add_.Set(value);
 123 }
 124
 125 }  // namespace base