Add an event bus for delivering events

[libs/game.git] / source / game / eventobserver.h

diff --git a/source/game/eventobserver.h b/source/game/eventobserver.h
new file mode 100644 (file)
index 0000000..31735a6
--- /dev/null
+++ b/source/game/eventobserver.h
@@ -0,0 +1,43 @@
+#ifndef MSP_GAME_EVENTOBSERVER_H_
+#define MSP_GAME_EVENTOBSERVER_H_
+
+#include <msp/core/algorithm.h>
+#include <msp/core/noncopyable.h>
+#include "eventbus.h"
+
+namespace Msp::Game {
+
+class EventSourceBase;
+
+class EventObserver: public NonCopyable
+{
+private:
+       EventBus &bus;
+       std::vector<EventSourceBase *> observed_sources;
+
+public:
+       EventObserver(EventBus &);
+       ~EventObserver();
+
+       template<typename T>
+       void observe(std::function<void(const T &)> cb)
+       { bus.add_observer<T>(*this, std::move(cb)); }
+
+       template<typename T, typename S>
+       void observe(S &, std::function<void(const T &)> );
+
+       void remove_source(EventSourceBase &);
+};
+
+template<typename T, typename S>
+void EventObserver::observe(S &src, std::function<void(const T &)> cb)
+{
+       src.add_observer(*this, std::move(cb));
+       auto i = lower_bound(observed_sources, &src);
+       if(i==observed_sources.end() || *i!=&src)
+               observed_sources.insert(i, &src);
+}
+
+} // namespace Msp::Game
+
+#endif