nitpicker: New signal handling, bg color config

This patch overhauls the signal handling of nitpicker to clear the way
towards dynamic reconfiguration. Furthermore, it moves the
implementation of the global-keys handling and input utilities to
separate files.

os/src/server/nitpicker/README

@@ -65,3 +65,10 @@ the "launchpad -> testnit" program is running. As soon as testnit gets started
 by launchpad, testnit will receive the events. If the order was reversed,
 launchpad would always receive the events.
 
+Background color
+----------------
+
+The background color can be defined via the '<background>' config node:
+
+! <background color="#112233" />
+

os/src/server/nitpicker/genode/global_keys.cc

@@ -0,0 +1,90 @@
+/*
+ * \brief  Global keys handling
+ * \author Norman Feske
+ * \date   2013-09-07
+ */
+
+/*
+ * Copyright (C) 2013 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+/* Genode includes */
+#include <os/config.h>
+
+/* local includes */
+#include "global_keys.h"
+
+
+Global_keys::Policy *Global_keys::_lookup_policy(char const *key_name)
+{
+	for (unsigned i = 0; i < NUM_POLICIES; i++)
+		if (Genode::strcmp(key_name, Input::key_name((Input::Keycode)i)) == 0)
+			return &_policies[i];
+
+	return 0;
+}
+
+
+void Global_keys::apply_config(Session_list &session_list)
+{
+	for (unsigned i = 0; i < NUM_POLICIES; i++)
+		_policies[i].undefine();
+
+	using Genode::Xml_node;
+	try {
+		Xml_node node = Genode::config()->xml_node().sub_node("global-keys").sub_node("key");
+
+		for (; ; node = node.next("key")) {
+
+			if (!node.has_attribute("name")) {
+				PWRN("attribute 'name' missing in <key> config node");
+				continue;
+			}
+
+			char name[32]; name[0] = 0;
+			node.attribute("name").value(name, sizeof(name));
+
+			Policy * policy = _lookup_policy(name);
+			if (!policy) {
+				PWRN("invalid key name \"%s\"", name);
+				continue;
+			}
+
+			/* if two policies match, give precedence to policy defined first */
+			if (policy->defined())
+				continue;
+
+			if (node.has_attribute("operation")) {
+				Xml_node::Attribute operation = node.attribute("operation");
+
+				if (operation.has_value("kill")) {
+					policy->operation_kill();
+					continue;
+				} else if (operation.has_value("xray")) {
+					policy->operation_xray();
+					continue;
+				} else {
+					char buf[32]; buf[0] = 0;
+					operation.value(buf, sizeof(buf));
+					PWRN("unknown operation \"%s\" for key %s", buf, name);
+				}
+				continue;
+			}
+
+			if (!node.has_attribute("label")) {
+				PWRN("missing 'label' attribute for key %s", name);
+				continue;
+			}
+
+			/* assign policy to matching client session */
+			for (Session *s = session_list.first(); s; s = s->next())
+				if (node.attribute("label").has_value(s->label()))
+					policy->client(s);
+		}
+
+	} catch (Xml_node::Nonexistent_sub_node) { }
+}
+

os/src/server/nitpicker/genode/main.cc

@@ -31,15 +31,24 @@
 #include <nitpicker_gfx/pixel_rgb565.h>
 #include <nitpicker_gfx/string.h>
 #include <os/session_policy.h>
+#include <os/signal_rpc_dispatcher.h>
 
 /* local includes */
+#include "input.h"
 #include "big_mouse.h"
 #include "background.h"
-#include "user_state.h"
 #include "clip_guard.h"
 #include "mouse_cursor.h"
 #include "chunky_menubar.h"
 
+namespace Input       { using namespace Genode;  }
+namespace Input       { class Session_component; }
+namespace Framebuffer { using namespace Genode;  }
+namespace Framebuffer { class Session_component; }
+namespace Nitpicker   { using namespace Genode;  }
+namespace Nitpicker   { class Session_component; }
+namespace Nitpicker   { template <typename> class Root; }
+
 
 /***************
  ** Utilities **
@@ -53,16 +62,16 @@
  */
 static Color session_color(char const *session_args)
 {
+	using namespace Genode;
+
 	/* use white by default */
 	Color color = WHITE;
 
 	try {
-		Genode::Session_policy policy(session_args);
+		Session_policy policy(session_args);
 
 		/* read color attribute */
-		char color_buf[8];
+		policy.attribute("color").value(&color);
-		policy.attribute("color").value(color_buf, sizeof(color_buf));
-		Genode::ascii_to(color_buf, &color);
 	} catch (...) { }
 
 	return color;
@@ -207,9 +216,7 @@ class Chunky_dataspace_texture : public Buffer, public Chunky_texture<PT>
  ** Input sub session **
  ***********************/
 
-namespace Input {
+class Input::Session_component : public Genode::Rpc_object<Session>
-
-	class Session_component : public Genode::Rpc_object<Session>
 {
 	public:
 
@@ -220,7 +227,7 @@ namespace Input {
 		/*
 		 * Exported event buffer dataspace
 		 */
-			Genode::Attached_ram_dataspace _ev_ram_ds;
+		Attached_ram_dataspace _ev_ram_ds;
 
 		/*
 		 * Local event buffer that is copied
@@ -232,14 +239,14 @@ namespace Input {
 
 	public:
 
-			static Genode::size_t ev_ds_size() {
+		static size_t ev_ds_size() {
-				return Genode::align_addr(MAX_EVENTS*sizeof(Event), 12); }
+			return align_addr(MAX_EVENTS*sizeof(Event), 12); }
 
 		/**
 		 * Constructor
 		 */
 		Session_component():
-				_ev_ram_ds(Genode::env()->ram_session(), ev_ds_size()),
+			_ev_ram_ds(env()->ram_session(), ev_ds_size()),
 			_num_ev(0) { }
 
 		/**
@@ -259,7 +266,7 @@ namespace Input {
 		 ** Input session interface **
 		 *****************************/
 
-			Genode::Dataspace_capability dataspace() { return _ev_ram_ds.cap(); }
+		Dataspace_capability dataspace() { return _ev_ram_ds.cap(); }
 
 		bool is_pending() const { return _num_ev > 0; }
 
@@ -276,16 +283,13 @@ namespace Input {
 			return ev_cnt;
 		}
 };
-}
 
 
 /*****************************
  ** Framebuffer sub session **
  *****************************/
 
-namespace Framebuffer {
+class Framebuffer::Session_component : public Genode::Rpc_object<Session>
-
-	class Session_component : public Genode::Rpc_object<Session>
 {
 	private:
 
@@ -309,7 +313,7 @@ namespace Framebuffer {
 			_buffer(buffer), _view_stack(view_stack), _session(session),
 			_flush_merger(flush_merger), _framebuffer(framebuffer) { }
 
-			Genode::Dataspace_capability dataspace() { return _buffer.ds_cap(); }
+		Dataspace_capability dataspace() { return _buffer.ds_cap(); }
 
 		void release() { }
 
@@ -319,7 +323,7 @@ namespace Framebuffer {
 			            _buffer.format());
 		}
 
-			void mode_sigh(Genode::Signal_context_capability) { }
+		void mode_sigh(Signal_context_capability) { }
 
 		void refresh(int x, int y, int w, int h)
 		{
@@ -335,7 +339,6 @@ namespace Framebuffer {
 			_flush_merger.defer = true;
 		}
 };
-}
 
 
 class View_component : public Genode::List<View_component>::Element,
@@ -343,9 +346,11 @@ class View_component : public Genode::List<View_component>::Element,
 {
 	private:
 
+		typedef Genode::Rpc_entrypoint Rpc_entrypoint;
+
 		View_stack     &_view_stack;
 		::View          _view;
-		Genode::Rpc_entrypoint &_ep;
+		Rpc_entrypoint &_ep;
 
 	public:
 
@@ -353,7 +358,7 @@ class View_component : public Genode::List<View_component>::Element,
 		 * Constructor
 		 */
 		View_component(::Session &session, View_stack &view_stack,
-		               Genode::Rpc_entrypoint &ep):
+		               Rpc_entrypoint &ep):
 			_view_stack(view_stack),
 			_view(session,
 			      session.stay_top() ? ::View::STAY_TOP : ::View::NOT_STAY_TOP,
@@ -380,7 +385,9 @@ class View_component : public Genode::List<View_component>::Element,
 
 		int stack(Nitpicker::View_capability neighbor_cap, bool behind, bool redraw)
 		{
-			Genode::Object_pool<View_component>::Guard nvc(_ep.lookup_and_lock(neighbor_cap));
+			using namespace Genode;
+
+			Object_pool<View_component>::Guard nvc(_ep.lookup_and_lock(neighbor_cap));
 
 			::View *neighbor_view = nvc ? &nvc->view() : 0;
 
@@ -400,9 +407,8 @@ class View_component : public Genode::List<View_component>::Element,
  ** Implementation of Nitpicker service **
  *****************************************/
 
-namespace Nitpicker {
+class Nitpicker::Session_component : public Genode::Rpc_object<Session>,
-
+                                     public ::Session
-	class Session_component : public Genode::Rpc_object<Session>, public ::Session
 {
 	private:
 
@@ -416,11 +422,11 @@ namespace Nitpicker {
 		 * Entrypoint that is used for the views, input session,
 		 * and framebuffer session.
 		 */
-			Genode::Rpc_entrypoint &_ep;
+		Rpc_entrypoint &_ep;
 
 		View_stack &_view_stack;
 
-			Genode::List<View_component> _view_list;
+		List<View_component> _view_list;
 
 		/* capabilities for sub sessions */
 		Framebuffer::Session_capability _framebuffer_session_cap;
@@ -437,7 +443,7 @@ namespace Nitpicker {
 		                  ::Buffer               &buffer,
 		                  Texture          const &texture,
 		                  View_stack             &view_stack,
-			                  Genode::Rpc_entrypoint &ep,
+		                  Rpc_entrypoint         &ep,
 		                  Flush_merger           &flush_merger,
 		                  Framebuffer::Session   &framebuffer,
 		                  int                     v_offset,
@@ -503,7 +509,7 @@ namespace Nitpicker {
 			 * FIXME: Do not allocate View meta data from Heap!
 			 *        Use a heap partition!
 			 */
-				View_component *view = new (Genode::env()->heap())
+			View_component *view = new (env()->heap())
 			                       View_component(*this, _view_stack, _ep);
 
 			_view_list.insert(view);
@@ -518,13 +524,13 @@ namespace Nitpicker {
 			_view_stack.remove_view(vc->view());
 			_ep.dissolve(vc);
 			_view_list.remove(vc);
-				destroy(Genode::env()->heap(), vc);
+			destroy(env()->heap(), vc);
 		}
 
 		int background(View_capability view_cap)
 		{
 			if (_provides_default_bg) {
-					Genode::Object_pool<View_component>::Guard vc(_ep.lookup_and_lock(view_cap));
+				Object_pool<View_component>::Guard vc(_ep.lookup_and_lock(view_cap));
 				vc->view().background(true);
 				_view_stack.default_background(vc->view());
 				return 0;
@@ -534,7 +540,7 @@ namespace Nitpicker {
 			if (::Session::background()) ::Session::background()->background(false);
 
 			/* assign session background */
-				Genode::Object_pool<View_component>::Guard vc(_ep.lookup_and_lock(view_cap));
+			Object_pool<View_component>::Guard vc(_ep.lookup_and_lock(view_cap));
 			::Session::background(&vc->view());
 
 			/* switch background view to background mode */
@@ -546,7 +552,7 @@ namespace Nitpicker {
 
 
 template <typename PT>
-	class Root : public Genode::Root_component<Session_component>
+class Nitpicker::Root : public Genode::Root_component<Session_component>
 {
 	private:
 
@@ -563,36 +569,36 @@ namespace Nitpicker {
 		Session_component *_create_session(const char *args)
 		{
 			PINF("create session with args: %s\n", args);
-				Genode::size_t ram_quota = Genode::Arg_string::find_arg(args, "ram_quota").ulong_value(0);
+			size_t ram_quota = Arg_string::find_arg(args, "ram_quota").ulong_value(0);
 
 			int v_offset = _default_v_offset;
 
 			/* determine buffer size of the session */
-				Area size(Genode::Arg_string::find_arg(args, "fb_width" ).long_value(_scr_size.w()),
+			Area size(Arg_string::find_arg(args, "fb_width" ).long_value(_scr_size.w()),
-				          Genode::Arg_string::find_arg(args, "fb_height").long_value(_scr_size.h() - v_offset));
+			          Arg_string::find_arg(args, "fb_height").long_value(_scr_size.h() - v_offset));
 
 			char label_buf[::Session::LABEL_LEN];
-				Genode::Arg_string::find_arg(args, "label").string(label_buf, sizeof(label_buf), "<unlabeled>");
+			Arg_string::find_arg(args, "label").string(label_buf, sizeof(label_buf), "<unlabeled>");
 
-				bool use_alpha = Genode::Arg_string::find_arg(args, "alpha").bool_value(false);
+			bool use_alpha = Arg_string::find_arg(args, "alpha").bool_value(false);
-				bool stay_top  = Genode::Arg_string::find_arg(args, "stay_top").bool_value(false);
+			bool stay_top  = Arg_string::find_arg(args, "stay_top").bool_value(false);
 
-				Genode::size_t texture_num_bytes = Chunky_dataspace_texture<PT>::calc_num_bytes(size, use_alpha);
+			size_t texture_num_bytes = Chunky_dataspace_texture<PT>::calc_num_bytes(size, use_alpha);
 
-				Genode::size_t required_quota = texture_num_bytes
+			size_t required_quota = texture_num_bytes
 			                      + Input::Session_component::ev_ds_size();
 
 			if (ram_quota < required_quota) {
 				PWRN("Insufficient dontated ram_quota (%zd bytes), require %zd bytes",
 				     ram_quota, required_quota);
-					throw Genode::Root::Quota_exceeded();
+				throw Root::Quota_exceeded();
 			}
 
 			/* allocate texture */
 			Chunky_dataspace_texture<PT> *cdt;
 			cdt = new (md_alloc()) Chunky_dataspace_texture<PT>(size, use_alpha);
 
-				bool provides_default_bg = (Genode::strcmp(label_buf, "backdrop") == 0);
+			bool provides_default_bg = (strcmp(label_buf, "backdrop") == 0);
 
 			Session_component *session = new (md_alloc())
 				Session_component(label_buf, *cdt, *cdt, _view_stack, *ep(),
@@ -628,251 +634,43 @@ namespace Nitpicker {
 		 * Constructor
 		 */
 		Root(Session_list &session_list, Global_keys &global_keys,
-			     Genode::Rpc_entrypoint &session_ep, Area scr_size,
+		     Rpc_entrypoint &session_ep, Area scr_size,
-			     View_stack &view_stack, Genode::Allocator &md_alloc,
+		     View_stack &view_stack, Allocator &md_alloc,
 		     Flush_merger &flush_merger,
 		     Framebuffer::Session &framebuffer, int default_v_offset)
 		:
-				Genode::Root_component<Session_component>(&session_ep, &md_alloc),
+			Root_component<Session_component>(&session_ep, &md_alloc),
 			_session_list(session_list), _global_keys(global_keys),
 			_scr_size(scr_size), _view_stack(view_stack), _flush_merger(flush_merger),
 			_framebuffer(framebuffer), _default_v_offset(default_v_offset) { }
 };
-}
 
 
-/*******************
+void wait_and_dispatch_one_signal(Genode::Signal_receiver &sig_rec)
- ** Input handler **
- *******************/
-
-struct Input_handler
 {
-	GENODE_RPC(Rpc_do_input_handling, void, do_input_handling);
+	using namespace Genode;
-	GENODE_RPC_INTERFACE(Rpc_do_input_handling);
-};
-
-
-class Input_handler_component : public Genode::Rpc_object<Input_handler,
-                                                          Input_handler_component>
-{
-	private:
-
-		User_state              &_user_state;
-		View                    &_mouse_cursor;
-		Area               const _mouse_size;
-		Flush_merger            &_flush_merger;
-		Input::Session          &_input;
-		Input::Event            *_ev_buf;
-		Framebuffer::Session    &_framebuffer;
-		Genode::Signal_receiver &_sig_rec;
-
-	public:
-
-		/**
-		 * Constructor
-		 */
-		Input_handler_component(User_state &user_state, View &mouse_cursor,
-		                        Area mouse_size, Flush_merger &flush_merger,
-		                        Input::Session &input,
-		                        Framebuffer::Session &framebuffer,
-		                        Genode::Signal_receiver &sig_rec)
-		:
-			_user_state(user_state), _mouse_cursor(mouse_cursor),
-			_mouse_size(mouse_size), _flush_merger(flush_merger),
-			_input(input),
-			_ev_buf(Genode::env()->rm_session()->attach(_input.dataspace())),
-			_framebuffer(framebuffer), _sig_rec(sig_rec)
-		{ }
-
-		/**
-		 * Determine number of events that can be merged into one
-		 *
-		 * \param ev   pointer to first event array element to check
-		 * \param max  size of the event array
-		 * \return     number of events subjected to merge
-		 */
-		unsigned _num_consecutive_events(Input::Event const *ev, unsigned max)
-		{
-			if (max < 1) return 0;
-			if (ev->type() != Input::Event::MOTION) return 1;
-
-			bool first_is_absolute = ev->is_absolute_motion();
-
-			/* iterate until we get a different event type, start at second */
-			unsigned cnt = 1;
-			for (ev++ ; cnt < max; cnt++, ev++) {
-				if (ev->type() != Input::Event::MOTION) break;
-				if (first_is_absolute != ev->is_absolute_motion()) break;
-			}
-			return cnt;
-		}
-
-		/**
-		 * Merge consecutive motion events
-		 *
-		 * \param ev  event array to merge
-		 * \param n   number of events to merge
-		 * \return    merged motion event
-		 */
-		static Input::Event _merge_motion_events(Input::Event const *ev, unsigned n)
-		{
-			Input::Event res;
-			for (unsigned i = 0; i < n; i++, ev++)
-				res = Input::Event(Input::Event::MOTION, 0, ev->ax(), ev->ay(),
-				                   res.rx() + ev->rx(), res.ry() + ev->ry());
-			return res;
-		}
-
-		void _import_input_events(unsigned num_ev)
-		{
-			/*
-			 * Take events from input event buffer, merge consecutive motion
-			 * events, and pass result to the user state.
-			 */
-			for (unsigned src_ev_cnt = 0; src_ev_cnt < num_ev; src_ev_cnt++) {
-
-				Input::Event *e = &_ev_buf[src_ev_cnt];
-				Input::Event curr = *e;
-
-				if (e->type() == Input::Event::MOTION) {
-					unsigned n = _num_consecutive_events(e, num_ev - src_ev_cnt);
-					curr = _merge_motion_events(e, n);
-
-					/* skip merged events */
-					src_ev_cnt += n - 1;
-				}
 
 	/*
-				 * If subsequential relative motion events are merged to
+	 * We call the signal dispatcher outside of the scope of 'Signal'
-				 * a zero-motion event, drop it. Otherwise, it would be
+	 * object because we block the RPC interface in the input handler
-				 * misinterpreted as absolute event pointing to (0, 0).
+	 * when the kill mode gets actived. While kill mode is active, we
+	 * do not serve incoming RPC requests but we need to stay responsive
+	 * to user input. Hence, we wait for signals in the input dispatcher
+	 * in this case. An already existing 'Signal' object would lock the
+	 * signal receiver and thereby prevent this nested way of signal
+	 * handling.
 	 */
-				if (e->is_relative_motion() && curr.rx() == 0 && curr.ry() == 0)
+	Signal_dispatcher_base *dispatcher = 0;
-					continue;
+	unsigned num = 0;
 
-				/* pass event to user state */
-				_user_state.handle_event(curr);
-			}
-		}
-
-		/**
-		 * This function is called periodically from the timer loop
-		 */
-		void do_input_handling()
 	{
-			do {
+		Signal sig = sig_rec.wait_for_signal();
-				Point old_mouse_pos = _user_state.mouse_pos();
+		dispatcher = dynamic_cast<Signal_dispatcher_base *>(sig.context());
-
+		num        = sig.num();
-				/* handle batch of pending events */
-				if (_input.is_pending())
-					_import_input_events(_input.flush());
-
-				Point new_mouse_pos = _user_state.mouse_pos();
-
-				/* update mouse cursor */
-				if (old_mouse_pos != new_mouse_pos)
-					_user_state.viewport(_mouse_cursor,
-					                     Rect(new_mouse_pos, _mouse_size),
-					                     Point(), true);
-
-				/* flush dirty pixels to physical frame buffer */
-				if (_flush_merger.defer == false) {
-					Rect r = _flush_merger.to_be_flushed();
-					if (r.valid())
-						_framebuffer.refresh(r.x1(), r.y1(), r.w(), r.h());
-					_flush_merger.reset();
-				}
-				_flush_merger.defer = false;
-
-				/*
-				 * In kill mode, we never leave the dispatch function to block
-				 * RPC calls from Nitpicker clients. We block for signals here
-				 * to make the spinning for the end of the kill mode less
-				 * painful for all non-blocked processes.
-				 */
-				if (_user_state.kill())
-					_sig_rec.wait_for_signal();
-
-			} while (_user_state.kill());
-		}
-};
-
-
-typedef Pixel_rgb565 PT;  /* physical pixel type */
-
-
-/*****************************
- ** Handling of global keys **
- *****************************/
-
-Global_keys::Policy *Global_keys::_lookup_policy(char const *key_name)
-{
-	for (unsigned i = 0; i < NUM_POLICIES; i++)
-		if (Genode::strcmp(key_name, Input::key_name((Input::Keycode)i)) == 0)
-			return &_policies[i];
-
-	return 0;
 	}
 
-
+	if (dispatcher)
-void Global_keys::apply_config(Session_list &session_list)
+		dispatcher->dispatch(num);
-{
-	for (unsigned i = 0; i < NUM_POLICIES; i++)
-		_policies[i].undefine();
-
-	using Genode::Xml_node;
-	try {
-		Xml_node node = Genode::config()->xml_node().sub_node("global-keys").sub_node("key");
-
-		for (; ; node = node.next("key")) {
-
-			if (!node.has_attribute("name")) {
-				PWRN("attribute 'name' missing in <key> config node");
-				continue;
-			}
-
-			char name[32]; name[0] = 0;
-			node.attribute("name").value(name, sizeof(name));
-
-			Policy * policy = _lookup_policy(name);
-			if (!policy) {
-				PWRN("invalid key name \"%s\"", name);
-				continue;
-			}
-
-			/* if two policies match, give precedence to policy defined first */
-			if (policy->defined())
-				continue;
-
-			if (node.has_attribute("operation")) {
-				Xml_node::Attribute operation = node.attribute("operation");
-
-				if (operation.has_value("kill")) {
-					policy->operation_kill();
-					continue;
-				} else if (operation.has_value("xray")) {
-					policy->operation_xray();
-					continue;
-				} else {
-					char buf[32]; buf[0] = 0;
-					operation.value(buf, sizeof(buf));
-					PWRN("unknown operation \"%s\" for key %s", buf, name);
-				}
-				continue;
-			}
-
-			if (!node.has_attribute("label")) {
-				PWRN("missing 'label' attribute for key %s", name);
-				continue;
-			}
-
-			/* assign policy to matching client session */
-			for (Session *s = session_list.first(); s; s = s->next())
-				if (node.attribute("label").has_value(s->label()))
-					policy->client(s);
-		}
-
-	} catch (Xml_node::Nonexistent_sub_node) { }
 }
 
 
@@ -880,6 +678,9 @@ void Global_keys::apply_config(Session_list &session_list)
  ** Main program **
  ******************/
 
+typedef Pixel_rgb565 PT;  /* physical pixel type */
+
+
 int main(int argc, char **argv)
 {
 	using namespace Genode;
@@ -891,6 +692,9 @@ int main(int argc, char **argv)
 	static Input::Connection       input;
 	static Cap_connection          cap;
 
+	static Input::Event * const ev_buf =
+		env()->rm_session()->attach(input.dataspace());
+
 	/*
 	 * Initialize server entry point
 	 */
@@ -922,13 +726,6 @@ int main(int argc, char **argv)
 
 	static Session_list session_list;
 
-	/*
-	 * Apply initial global-key policy to turn X-ray and kill keys into
-	 * effect. The policy will be updated each time the config changes,
-	 * or when a session appears or disappears.
-	 */
-	global_keys.apply_config(session_list);
-
 	static User_state user_state(global_keys, screen, menubar);
 
 	/*
@@ -958,35 +755,98 @@ int main(int argc, char **argv)
 	                                   screen, framebuffer,
 	                                   MENUBAR_HEIGHT);
 
-	env()->parent()->announce(ep.manage(&np_root));
+	static Signal_receiver sig_rec;
 
 	/*
-	 * Schedule periodic timer signals every 10 milliseconds
+	 * Configuration-update dispatcher, executed in the context of the RPC
+	 * entrypoint.
+	 *
+	 * In addition to installing the signal dispatcher, we trigger first signal
+	 * manually to turn the initial configuration into effect.
+	 */
+	static auto config_func = [&](unsigned)
+	{
+		config()->reload();
+		global_keys.apply_config(session_list);
+		try {
+			config()->xml_node().sub_node("background")
+			                    .attribute("color").value(&background.color);
+		} catch (...) { }
+		user_state.update_all_views();
+	};
+
+	auto config_dispatcher = signal_rpc_dispatcher(config_func);
+
+	Signal_context_capability config_sigh = config_dispatcher.manage(sig_rec, ep);
+
+	config()->sigh(config_sigh);
+
+	Signal_transmitter(config_sigh).submit();
+
+	/*
+	 * Input dispatcher, executed in the contect of the RPC entrypoint
+	 */
+	static auto input_func = [&](unsigned num)
+	{
+		/*
+		 * If kill mode is already active, we got recursively called from
+		 * within this 'input_func' (via 'wait_and_dispatch_one_signal').
+		 * In this case, return immediately. New input events will be
+		 * processed in the local 'do' loop.
+		 */
+		if (user_state.kill())
+			return;
+
+		do {
+			Point const old_mouse_pos = user_state.mouse_pos();
+
+			/* handle batch of pending events */
+			if (input.is_pending())
+				import_input_events(ev_buf, input.flush(), user_state);
+
+			Point const new_mouse_pos = user_state.mouse_pos();
+
+			/* update mouse cursor */
+			if (old_mouse_pos != new_mouse_pos)
+				user_state.viewport(mouse_cursor,
+				                    Rect(new_mouse_pos, mouse_size),
+				                    Point(), true);
+
+			/* flush dirty pixels to physical frame buffer */
+			if (screen.defer == false) {
+				Rect const r = screen.to_be_flushed();
+				if (r.valid())
+					framebuffer.refresh(r.x1(), r.y1(), r.w(), r.h());
+				screen.reset();
+			}
+			screen.defer = false;
+
+			/*
+			 * In kill mode, we do not leave the dispatch function in order to
+			 * block RPC calls from Nitpicker clients. We block for signals
+			 * here to stay responsive to user input and configuration changes.
+			 * Nested calls of 'input_func' are prevented by the condition
+			 * check for 'user_state.kill()' at the beginning of the handler.
+			 */
+			if (user_state.kill())
+				wait_and_dispatch_one_signal(sig_rec);
+
+		} while (user_state.kill());
+	};
+
+	auto input_dispatcher = signal_rpc_dispatcher(input_func);
+
+	/*
+	 * Dispatch input on periodic timer signals every 10 milliseconds
 	 */
 	static Timer::Connection timer;
-	static Signal_receiver   sig_rec;
+	timer.sigh(input_dispatcher.manage(sig_rec, ep));
-	Signal_context           timer_sig_ctx;
-
-	timer.sigh(sig_rec.manage(&timer_sig_ctx));
 	timer.trigger_periodic(10*1000);
 
-	/*
+	env()->parent()->announce(ep.manage(&np_root));
-	 * Initialize input handling
-	 *
-	 * We serialize the input handling with the client interfaces via
-	 * Nitpicker's entry point. For this, we implement the input handling
-	 * as a 'Rpc_object' and perform RPC calls to this local object in a
-	 * periodic fashion.
-	 */
-	static Input_handler_component
-		input_handler(user_state, mouse_cursor, mouse_size,
-		              screen, input, framebuffer, sig_rec);
 
-	Capability<Input_handler> input_handler_cap = ep.manage(&input_handler);
+	for (;;)
+		wait_and_dispatch_one_signal(sig_rec);
 
-	for (;;) {
-		sig_rec.wait_for_signal();
-		input_handler_cap.call<Input_handler::Rpc_do_input_handling>();
-	}
 	return 0;
 }

os/src/server/nitpicker/genode/target.mk

@@ -3,9 +3,13 @@ LIBS     = base blit config
 SRC_CC   = main.cc \
            view_stack.cc \
            view.cc \
-           user_state.cc
+           user_state.cc \
+           global_keys.cc
 SRC_BIN  = default.tff
 
+# enable C++11 support
+CC_CXX_OPT += -std=gnu++11
+
 INC_DIR  = $(PRG_DIR)/../include \
            $(PRG_DIR)/../data
 

os/src/server/nitpicker/include/background.h

@@ -19,6 +19,8 @@
 
 struct Background : private Texture, Session, View
 {
+	Color color;
+
 	/*
 	 * The background uses no texture. Therefore
 	 * we can pass a null pointer as texture argument
@@ -28,7 +30,8 @@ struct Background : private Texture, Session, View
 	:
 		Texture(Area(0, 0)), Session("", *this, 0, BLACK),
 		View(*this, View::NOT_STAY_TOP, View::NOT_TRANSPARENT,
-		     View::BACKGROUND, Rect(Point(0, 0), size))
+		     View::BACKGROUND, Rect(Point(0, 0), size)),
+		color(25, 37, 50)
 	{ }
 
 
@@ -49,7 +52,7 @@ struct Background : private Texture, Session, View
 	void draw(Canvas &canvas, Mode const &mode) const
 	{
 		Clip_guard clip_guard(canvas, *this);
-		canvas.draw_box(*this, Color(25, 37, 50));
+		canvas.draw_box(*this, color);
 	}
 };
 

os/src/server/nitpicker/include/input.h

@@ -0,0 +1,98 @@
+/*
+ * \brief  Input handling utilities
+ * \author Norman Feske
+ * \date   2013-09-07
+ */
+
+/*
+ * Copyright (C) 2013 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#ifndef _INPUT_H_
+#define _INPUT_H_
+
+/* Genode includes */
+#include <input/event.h>
+
+/* local includes */
+#include "user_state.h"
+
+
+/**
+ * Determine number of events that can be merged into one
+ *
+ * \param ev   pointer to first event array element to check
+ * \param max  size of the event array
+ * \return     number of events subjected to merge
+ */
+static unsigned num_consecutive_events(Input::Event const *ev, unsigned max)
+{
+	if (max < 1) return 0;
+	if (ev->type() != Input::Event::MOTION) return 1;
+
+	bool first_is_absolute = ev->is_absolute_motion();
+
+	/* iterate until we get a different event type, start at second */
+	unsigned cnt = 1;
+	for (ev++ ; cnt < max; cnt++, ev++) {
+		if (ev->type() != Input::Event::MOTION) break;
+		if (first_is_absolute != ev->is_absolute_motion()) break;
+	}
+	return cnt;
+}
+
+
+/**
+ * Merge consecutive motion events
+ *
+ * \param ev  event array to merge
+ * \param n   number of events to merge
+ * \return    merged motion event
+ */
+static Input::Event merge_motion_events(Input::Event const *ev, unsigned n)
+{
+	Input::Event res;
+	for (unsigned i = 0; i < n; i++, ev++)
+		res = Input::Event(Input::Event::MOTION, 0, ev->ax(), ev->ay(),
+		                   res.rx() + ev->rx(), res.ry() + ev->ry());
+	return res;
+}
+
+
+static void import_input_events(Input::Event *ev_buf, unsigned num_ev,
+                                User_state &user_state)
+{
+	/*
+	 * Take events from input event buffer, merge consecutive motion
+	 * events, and pass result to the user state.
+	 */
+	for (unsigned src_ev_cnt = 0; src_ev_cnt < num_ev; src_ev_cnt++) {
+
+		Input::Event *e = &ev_buf[src_ev_cnt];
+		Input::Event curr = *e;
+
+		if (e->type() == Input::Event::MOTION) {
+			unsigned n = num_consecutive_events(e, num_ev - src_ev_cnt);
+			curr = merge_motion_events(e, n);
+
+			/* skip merged events */
+			src_ev_cnt += n - 1;
+		}
+
+		/*
+		 * If subsequential relative motion events are merged to
+		 * a zero-motion event, drop it. Otherwise, it would be
+		 * misinterpreted as absolute event pointing to (0, 0).
+		 */
+		if (e->is_relative_motion() && curr.rx() == 0 && curr.ry() == 0)
+			continue;
+
+		/* pass event to user state */
+		user_state.handle_event(curr);
+	}
+}
+
+#endif /* _INPUT_H_ */

os/src/server/nitpicker/include/session.h

@@ -17,6 +17,9 @@
 /* Genode includes */
 #include <util/list.h>
 #include <util/string.h>
+#include <nitpicker_gfx/color.h>
+#include <nitpicker_gfx/geometry.h>
+#include <nitpicker_gfx/canvas.h>
 
 class Texture;
 class View;