Implemented a small kernel debugger add-on that triggers a redraw of the

entire screen when exiting the kernel debugger. It sets up a thread that sends
a message to the (currently hardcoded) desktop message looper. The desktop then
does mark the whole screen dirty which causes a full redraw.
Since interrupts need to be enabled I went with an asynchronous thread and
releasing a request sem in the add-ons' exit hook.
Added the add-on to the image as it shouldn't hurt to have it for now.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24025 a95241bf-73f2-0310-859d-f6bbb57e9c96

build/jam/HaikuImage

@@ -145,7 +145,8 @@ AddFilesToHaikuImage beos system add-ons kernel busses scsi
 AddFilesToHaikuImage beos system add-ons kernel busses usb
 	: <usb>uhci <usb>ehci ;
 AddFilesToHaikuImage beos system add-ons kernel console : vga_text ;
-AddFilesToHaikuImage beos system add-ons kernel debugger : <kdebug>hangman ;
+AddFilesToHaikuImage beos system add-ons kernel debugger
+	: <kdebug>hangman <kdebug>invalidate_on_exit ;
 AddFilesToHaikuImage beos system add-ons kernel file_systems
 	: $(BEOS_ADD_ONS_FILE_SYSTEMS) ;
 AddFilesToHaikuImage beos system add-ons kernel generic

src/add-ons/kernel/debugger/invalidate_on_exit/Jamfile

@@ -0,0 +1,7 @@
+SubDir HAIKU_TOP src add-ons kernel debugger invalidate_on_exit ;
+
+UsePrivateHeaders kernel ;
+
+KernelAddon <kdebug>invalidate_on_exit :
+	invalidate_on_exit.cpp
+	;

src/add-ons/kernel/debugger/invalidate_on_exit/invalidate_on_exit.cpp

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2008, Michael Lotz, mmlr@mlotz.ch
+ * Distributed under the terms of the MIT License.
+ */
+#include <debug.h>
+#include <signal.h>
+
+
+static sem_id sRequestSem = -1;
+
+
+static int32
+invalidate_loop(void *data)
+{
+	while (true) {
+		if (acquire_sem(sRequestSem) != B_OK)
+			break;
+
+		uint32 message[3];
+		message[0] = sizeof(message);	// size
+		message[1] = 'KDLE';			// message code
+		message[2] = 0;					// flags
+
+		// where "d:0:baron' stands for desktop x of user y which both
+		// currently are hardcoded and where '_PTL' is the port link code
+		write_port(find_port("d:0:baron"), '_PTL', &message, sizeof(message));
+	}
+
+	return 0;
+}
+
+
+static void
+exit_debugger()
+{
+	release_sem_etc(sRequestSem, 1, B_DO_NOT_RESCHEDULE);
+}
+
+
+static status_t
+std_ops(int32 op, ...)
+{
+	if (op == B_MODULE_INIT) {
+		sRequestSem = create_sem(0, "invalidate_loop_request");
+		if (sRequestSem < B_OK)
+			return sRequestSem;
+
+		thread_id thread = spawn_kernel_thread(&invalidate_loop,
+			"invalidate_loop", B_NORMAL_PRIORITY, NULL);
+		if (thread < B_OK)
+			return thread;
+
+		send_signal_etc(thread, SIGCONT, B_DO_NOT_RESCHEDULE);
+		return B_OK;
+	} else if (op == B_MODULE_UNINIT) {
+		// deleting the sem will also cause the thread to exit
+		delete_sem(sRequestSem);
+		sRequestSem = -1;
+		return B_OK;
+	}
+
+	return B_BAD_VALUE;
+}
+
+
+static struct debugger_module_info sModuleInfo = {
+	{
+		"debugger/invalidate_on_exit/v1",
+		B_KEEP_LOADED,
+		&std_ops
+	},
+
+	NULL,
+	exit_debugger
+};
+
+module_info *modules[] = { 
+	(module_info *)&sModuleInfo,
+	NULL
+};

src/servers/app/Desktop.cpp

@@ -633,6 +633,17 @@ Desktop::_DispatchMessage(int32 code, BPrivate::LinkReceiver &link)
 			break;
 		}
 
+		// ToDo: Remove this again. It is a message sent by the
+		// invalidate_on_exit kernel debugger add-on to trigger a redraw
+		// after exiting a kernel debugger session.
+		case 'KDLE':
+		{
+			BRegion dirty;
+			dirty.Include(fVirtualScreen.Frame());
+			MarkDirty(dirty);
+			break;
+		}
+
 		default:
 			printf("Desktop %d:%s received unexpected code %ld\n", 0, "baron", code);