1 files changed, 71 insertions, 0 deletions
diff --git a/xbmc/utils/Observer.cpp b/xbmc/utils/Observer.cpp
new file mode 100644
index 0000000..5c60a4b
--- /dev/null
+++ b/xbmc/utils/Observer.cpp
@@ -0,0 +1,71 @@
+/*
+ *  Copyright (C) 2005-2018 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+
+#include "Observer.h"
+
+#include <algorithm>
+#include <mutex>
+
+Observable &Observable::operator=(const Observable &observable)
+{
+  std::unique_lock<CCriticalSection> lock(m_obsCritSection);
+
+  m_bObservableChanged = static_cast<bool>(observable.m_bObservableChanged);
+  m_observers = observable.m_observers;
+
+  return *this;
+}
+
+bool Observable::IsObserving(const Observer &obs) const
+{
+  std::unique_lock<CCriticalSection> lock(m_obsCritSection);
+  return std::find(m_observers.begin(), m_observers.end(), &obs) != m_observers.end();
+}
+
+void Observable::RegisterObserver(Observer *obs)
+{
+  std::unique_lock<CCriticalSection> lock(m_obsCritSection);
+  if (!IsObserving(*obs))
+  {
+    m_observers.push_back(obs);
+  }
+}
+
+void Observable::UnregisterObserver(Observer *obs)
+{
+  std::unique_lock<CCriticalSection> lock(m_obsCritSection);
+  auto iter = std::remove(m_observers.begin(), m_observers.end(), obs);
+  if (iter != m_observers.end())
+    m_observers.erase(iter);
+}
+
+void Observable::NotifyObservers(const ObservableMessage message /* = ObservableMessageNone */)
+{
+  // Make sure the set/compare is atomic
+  // so we don't clobber the variable in a race condition
+  auto bNotify = m_bObservableChanged.exchange(false);
+
+  if (bNotify)
+    SendMessage(message);
+}
+
+void Observable::SetChanged(bool SetTo)
+{
+  m_bObservableChanged = SetTo;
+}
+
+void Observable::SendMessage(const ObservableMessage message)
+{
+  std::unique_lock<CCriticalSection> lock(m_obsCritSection);
+
+  for (auto& observer : m_observers)
+  {
+    observer->Notify(*this, message);
+  }
+}