xbmc/utils/Observer.cpp

   1 /*
   2  *  Copyright (C) 2005-2018 Team Kodi
   3  *  This file is part of Kodi - https://kodi.tv
   4  *
   5  *  SPDX-License-Identifier: GPL-2.0-or-later
   6  *  See LICENSES/README.md for more information.
   7  */
   8
   9
  10 #include "Observer.h"
  11
  12 #include <algorithm>
  13 #include <mutex>
  14
  15 Observable &Observable::operator=(const Observable &observable)
  16 {
  17   std::unique_lock<CCriticalSection> lock(m_obsCritSection);
  18
  19   m_bObservableChanged = static_cast<bool>(observable.m_bObservableChanged);
  20   m_observers = observable.m_observers;
  21
  22   return *this;
  23 }
  24
  25 bool Observable::IsObserving(const Observer &obs) const
  26 {
  27   std::unique_lock<CCriticalSection> lock(m_obsCritSection);
  28   return std::find(m_observers.begin(), m_observers.end(), &obs) != m_observers.end();
  29 }
  30
  31 void Observable::RegisterObserver(Observer *obs)
  32 {
  33   std::unique_lock<CCriticalSection> lock(m_obsCritSection);
  34   if (!IsObserving(*obs))
  35   {
  36     m_observers.push_back(obs);
  37   }
  38 }
  39
  40 void Observable::UnregisterObserver(Observer *obs)
  41 {
  42   std::unique_lock<CCriticalSection> lock(m_obsCritSection);
  43   auto iter = std::remove(m_observers.begin(), m_observers.end(), obs);
  44   if (iter != m_observers.end())
  45     m_observers.erase(iter);
  46 }
  47
  48 void Observable::NotifyObservers(const ObservableMessage message /* = ObservableMessageNone */)
  49 {
  50   // Make sure the set/compare is atomic
  51   // so we don't clobber the variable in a race condition
  52   auto bNotify = m_bObservableChanged.exchange(false);
  53
  54   if (bNotify)
  55     SendMessage(message);
  56 }
  57
  58 void Observable::SetChanged(bool SetTo)
  59 {
  60   m_bObservableChanged = SetTo;
  61 }
  62
  63 void Observable::SendMessage(const ObservableMessage message)
  64 {
  65   std::unique_lock<CCriticalSection> lock(m_obsCritSection);
  66
  67   for (auto& observer : m_observers)
  68   {
  69     observer->Notify(*this, message);
  70   }
  71 }