From 5ffc2443718f5514e4fe27d2aa4ac07022bc4917 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 24 Mar 2013 17:06:09 +0200
Subject: [PATCH] Allow event handling to be interrupted

---
 source/input/control.cpp | 11 ++++++-----
 source/input/device.h    | 23 ++++++++++++++++++++---
 source/input/hub.cpp     |  7 ++++---
 source/input/keyboard.h  |  2 +-
 4 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/source/input/control.cpp b/source/input/control.cpp
index f3f1919..18c2ffd 100644
--- a/source/input/control.cpp
+++ b/source/input/control.cpp
@@ -1,3 +1,4 @@
+#include <sigc++/bind_return.h>
 #include <msp/strings/lexicalcast.h>
 #include "control.h"
 #include "device.h"
@@ -54,8 +55,8 @@ void Control::capture(Device &d)
 {
 	notify_callbacks();
 	capture_dev = &d;
-	capture_dev->signal_button_press.connect(sigc::mem_fun(this, &Control::button_press));
-	capture_dev->signal_axis_motion.connect(sigc::mem_fun(this, &Control::axis_motion));
+	capture_dev->signal_button_press.connect(sigc::bind_return(sigc::mem_fun(this, &Control::button_press), false));
+	capture_dev->signal_axis_motion.connect(sigc::bind_return(sigc::mem_fun(this, &Control::axis_motion), false));
 }
 
 void Control::cancel_capture()
@@ -84,12 +85,12 @@ void Control::connect_signals()
 	case NONE:
 		break;
 	case BUTTON:
-		src.dev->signal_button_press.connect(sigc::mem_fun(this, &Control::button_press));
-		src.dev->signal_button_release.connect(sigc::mem_fun(this, &Control::button_release));
+		src.dev->signal_button_press.connect(sigc::bind_return(sigc::mem_fun(this, &Control::button_press), false));
+		src.dev->signal_button_release.connect(sigc::bind_return(sigc::mem_fun(this, &Control::button_release), false));
 		break;
 	case AXIS_POS:
 	case AXIS_NEG:
-		src.dev->signal_axis_motion.connect(sigc::mem_fun(this, &Control::axis_motion));
+		src.dev->signal_axis_motion.connect(sigc::bind_return(sigc::mem_fun(this, &Control::axis_motion), false));
 		break;
 	}
 }
diff --git a/source/input/device.h b/source/input/device.h
index 3338137..6a436ab 100644
--- a/source/input/device.h
+++ b/source/input/device.h
@@ -12,13 +12,30 @@ namespace Input {
 Base class for input devices.  Input devices have two types of controls:
 buttons and axes.  Buttons are either on or off.  Axes have a floating point
 value in the range [-1, 1].
+
+Event handlers return a boolean indicating whether the event is considered
+processed.  If a handler returns true, no further handlers are invoked.
 */
 class Device
 {
+protected:
+	struct EventAccumulator
+	{
+		typedef void result_type;
+
+		template<typename Iter>
+		result_type operator()(Iter begin, Iter end) const
+		{
+			for(Iter i=begin; i!=end; ++i)
+				if(*i)
+					return;
+		}
+	};
+
 public:
-	sigc::signal<void, unsigned> signal_button_press;
-	sigc::signal<void, unsigned> signal_button_release;
-	sigc::signal<void, unsigned, float, float> signal_axis_motion;
+	sigc::signal<bool, unsigned>::accumulated<EventAccumulator> signal_button_press;
+	sigc::signal<bool, unsigned>::accumulated<EventAccumulator> signal_button_release;
+	sigc::signal<bool, unsigned, float, float>::accumulated<EventAccumulator> signal_axis_motion;
 
 protected:
 	std::string name;
diff --git a/source/input/hub.cpp b/source/input/hub.cpp
index 4a2d553..13c88d6 100644
--- a/source/input/hub.cpp
+++ b/source/input/hub.cpp
@@ -1,5 +1,6 @@
 #include <stdexcept>
 #include <sigc++/bind.h>
+#include <sigc++/bind_return.h>
 #include <msp/core/hash.h>
 #include <msp/core/maputils.h>
 #include "hub.h"
@@ -21,9 +22,9 @@ void Hub::attach(Device &dev)
 		++tag;
 
 	devices[tag] = &dev;
-	dev.signal_button_press.connect(sigc::bind(sigc::mem_fun(this, &Hub::button_press), tag));
-	dev.signal_button_release.connect(sigc::bind(sigc::mem_fun(this, &Hub::button_release), tag));
-	dev.signal_axis_motion.connect(sigc::bind(sigc::mem_fun(this, &Hub::axis_motion), tag));
+	dev.signal_button_press.connect(sigc::bind_return(sigc::bind(sigc::mem_fun(this, &Hub::button_press), tag), false));
+	dev.signal_button_release.connect(sigc::bind_return(sigc::bind(sigc::mem_fun(this, &Hub::button_release), tag), false));
+	dev.signal_axis_motion.connect(sigc::bind_return(sigc::bind(sigc::mem_fun(this, &Hub::axis_motion), tag), false));
 }
 
 std::string Hub::get_button_name(unsigned btn) const
diff --git a/source/input/keyboard.h b/source/input/keyboard.h
index 822de31..babdf9a 100644
--- a/source/input/keyboard.h
+++ b/source/input/keyboard.h
@@ -15,7 +15,7 @@ are translated to platform-independent values.  See keys.h for a list.
 class Keyboard: public Device
 {
 public:
-	sigc::signal<void, StringCodec::unichar> signal_character;
+	sigc::signal<bool, StringCodec::unichar>::accumulated<EventAccumulator> signal_character;
 
 private:
 	Graphics::Window &window;
-- 
2.45.2