base/metrics/user_metrics.cc

   1 // Copyright 2014 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/user_metrics.h"
   6
   7 #include <vector>
   8
   9 #include "base/lazy_instance.h"
  10 #include "base/threading/thread_checker.h"
  11
  12 namespace base {
  13 namespace {
  14
  15 // A helper class for tracking callbacks and ensuring thread-safety.
  16 class Callbacks {
  17  public:
  18   Callbacks() {}
  19
  20   // Records the |action|.
  21   void Record(const std::string& action) {
  22     DCHECK(thread_checker_.CalledOnValidThread());
  23     for (size_t i = 0; i < callbacks_.size(); ++i) {
  24       callbacks_[i].Run(action);
  25     }
  26   }
  27
  28   // Adds |callback| to the list of |callbacks_|.
  29   void AddCallback(const ActionCallback& callback) {
  30     DCHECK(thread_checker_.CalledOnValidThread());
  31     callbacks_.push_back(callback);
  32   }
  33
  34   // Removes the first instance of |callback| from the list of |callbacks_|, if
  35   // there is one.
  36   void RemoveCallback(const ActionCallback& callback) {
  37     DCHECK(thread_checker_.CalledOnValidThread());
  38     for (size_t i = 0; i < callbacks_.size(); ++i) {
  39       if (callbacks_[i].Equals(callback)) {
  40         callbacks_.erase(callbacks_.begin() + i);
  41         return;
  42       }
  43     }
  44   }
  45
  46  private:
  47   base::ThreadChecker thread_checker_;
  48   std::vector<ActionCallback> callbacks_;
  49
  50   DISALLOW_COPY_AND_ASSIGN(Callbacks);
  51 };
  52
  53 base::LazyInstance<Callbacks> g_callbacks = LAZY_INSTANCE_INITIALIZER;
  54
  55 }  // namespace
  56
  57 void RecordAction(const UserMetricsAction& action) {
  58   g_callbacks.Get().Record(action.str_);
  59 }
  60
  61 void RecordComputedAction(const std::string& action) {
  62   g_callbacks.Get().Record(action);
  63 }
  64
  65 void AddActionCallback(const ActionCallback& callback) {
  66   g_callbacks.Get().AddCallback(callback);
  67 }
  68
  69 void RemoveActionCallback(const ActionCallback& callback) {
  70   g_callbacks.Get().RemoveCallback(callback);
  71
  72 }
  73
  74 }  // namespace base