Add new event dispatching API.

svn-id: r42717

1 files changed, 136 insertions, 0 deletions

diff --git a/common/events.cpp b/common/events.cpp
new file mode 100644
index 0000000000..9cb5d8aba6
--- /dev/null
+++ b/common/events.cpp
@@ -0,0 +1,136 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#include "common/events.h"
+
+DECLARE_SINGLETON(Common::EventDispatcher);
+
+namespace Common {
+
+EventDispatcher::EventDispatcher() : _mapper(0) {
+}
+
+EventDispatcher::~EventDispatcher() {
+	for (Common::List<SourceEntry>::iterator i = _sources.begin(); i != _sources.end(); ++i) {
+		if (i->autoFree)
+			delete i->source;
+	}
+
+	for (Common::List<ObserverEntry>::iterator i = _observers.begin(); i != _observers.end(); ++i) {
+		if (i->autoFree)
+			delete i->observer;
+	}
+
+	delete _mapper;
+	_mapper = 0;
+}
+
+void EventDispatcher::dispatch() {
+	Common::Event event;
+
+	for (Common::List<SourceEntry>::iterator i = _sources.begin(); i != _sources.end(); ++i) {
+		while (i->source->pollEvent(event)) {
+			if (_mapper) {
+				if (_mapper->notifyEvent(event)) {
+					// We allow the event mapper to create multiple events, when
+					// eating an event.
+					while (_mapper->pollEvent(event))
+						dispatchEvent(event);
+
+					// Try getting another event from the current EventSource.
+					continue;
+				}
+			}
+
+			dispatchEvent(event);
+		}
+	}
+}
+
+void EventDispatcher::registerMapper(EventMapper *mapper) {
+	if (_mapper)
+		delete _mapper;
+	_mapper = mapper;
+}
+
+void EventDispatcher::registerSource(EventSource *source, bool autoFree) {
+	SourceEntry newEntry;
+
+	newEntry.source = source;
+	newEntry.autoFree = autoFree;
+
+	_sources.push_back(newEntry);
+}
+
+void EventDispatcher::unregisterSource(EventSource *source) {
+	for (Common::List<SourceEntry>::iterator i = _sources.begin(); i != _sources.end(); ++i) {
+		if (i->source == source) {
+			if (i->autoFree)
+				delete source;
+
+			_sources.erase(i);
+			return;
+		}
+	}	
+}
+
+void EventDispatcher::registerObserver(EventObserver *obs, uint priority, bool autoFree) {
+	ObserverEntry newEntry;
+
+	newEntry.observer = obs;
+	newEntry.priority = priority;
+	newEntry.autoFree = autoFree;
+
+	for (Common::List<ObserverEntry>::iterator i = _observers.begin(); i != _observers.end(); ++i) {
+		if (i->priority < priority) {
+			_observers.insert(i, newEntry);
+			return;
+		}
+	}
+
+	_observers.push_back(newEntry);
+}
+
+void EventDispatcher::unregisterObserver(EventObserver *obs) {
+	for (Common::List<ObserverEntry>::iterator i = _observers.begin(); i != _observers.end(); ++i) {
+		if (i->observer == obs) {
+			if (i->autoFree)
+				delete obs;
+
+			_observers.erase(i);
+			return;
+		}
+	}
+}
+
+void EventDispatcher::dispatchEvent(const Event &event) {
+	for (Common::List<ObserverEntry>::iterator i = _observers.begin(); i != _observers.end(); ++i) {
+		if (i->observer->notifyEvent(event))
+			break;
+	}
+}
+
+} // end of namespace Common
+