BACKENDS: Unify EventManager setup

2 files changed, 30 insertions, 2 deletions

diff --git a/common/system.cpp b/common/system.cpp
index 298f1d7d0d..2a0dfd8dfd 100644
--- a/common/system.cpp
+++ b/common/system.cpp
@@ -26,8 +26,9 @@
 #define FORBIDDEN_SYMBOL_EXCEPTION_fflush
 
 #include "common/system.h"
-#include "common/str.h"
+#include "common/events.h"
 #include "common/fs.h"
+#include "common/str.h"
 #include "common/textconsole.h"
 
 #include "backends/audiocd/default/default-audiocd.h"
@@ -36,19 +37,29 @@ OSystem *g_system = 0;
 
 OSystem::OSystem() {
 	_audiocdManager = 0;
+	_eventManager = 0;
 }
 
 OSystem::~OSystem() {
 	delete _audiocdManager;
+	_audiocdManager = 0;
+
+	delete _eventManager;
+	_eventManager = 0;
 }
 
 void OSystem::initBackend() {
+	// Init AudioCD manager
 #ifndef DISABLE_DEFAULT_AUDIOCD_MANAGER
 	if (!_audiocdManager)
 		_audiocdManager = new DefaultAudioCDManager();
 #endif
 	if (!_audiocdManager)
 		error("Backend failed to instantiate AudioCD manager");
+
+	// Verify Event manager has been set
+	if (!_eventManager)
+		error("Backend failed to instantiate Event manager");
 }
 
 bool OSystem::setGraphicsMode(const char *name) {
diff --git a/common/system.h b/common/system.h
index 85771cf982..87e74d928c 100644
--- a/common/system.h
+++ b/common/system.h
@@ -113,6 +113,21 @@ protected:
 	 */
 	AudioCDManager *_audiocdManager;
 
+	/**
+	 * For backend authors only, this pointer may be set by OSystem
+	 * subclasses to an EventManager instance. This is only useful
+	 * if your backend does not want to use the DefaultEventManager.
+	 *
+	 * This instance is returned by OSystem::getEventManager(),
+	 * and it is deleted by the OSystem destructor.
+	 *
+	 * A backend may set this pointer in its initBackend() method,
+	 * its constructor or somewhere in between; but it must
+	 * set it no later than in its initBackend() implementation, because
+	 * OSystem::initBackend() will by default create a DefaultEventManager
+	 * instance if _eventManager has not yet been set.
+	 */
+	Common::EventManager *_eventManager;
 public:
 
 	/**
@@ -848,7 +863,9 @@ public:
 	 * Return the event manager singleton. For more information, refer
 	 * to the EventManager documentation.
 	 */
-	virtual Common::EventManager *getEventManager() = 0;
+	inline Common::EventManager *getEventManager() {
+		return _eventManager;
+	}
 
 	/**
 	 * Register hardware keys with keymapper