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 75
