Provide Xorg/net wm process ID (#7445)

Adding support for _NET_WM_PID as defined in Extended Window Manager Hints
Move verbose messaging to setupXorgTopLevelWindow method as Xorg messages should only occur when running in Xorg env.
Irrlicht returns the XDisplay as a void* and XWindow as an unsigned long so reinterpret those as the appropriate type. Also fixed a spaces for tab formating issue

src/client/clientlauncher.cpp

@@ -96,15 +96,13 @@ bool ClientLauncher::run(GameParams &game_params, const Settings &cmd_args)
 		return true;
 	}
 
-	video::IVideoDriver *video_driver = RenderingEngine::get_video_driver();
-	if (video_driver == NULL) {
+	if (RenderingEngine::get_video_driver() == NULL) {
 		errorstream << "Could not initialize video driver." << std::endl;
 		return false;
 	}
 
-	RenderingEngine::setXorgClassHint(video_driver->getExposedVideoData(), PROJECT_NAME_C);
-	RenderingEngine::get_instance()->setWindowIcon();
-
+	RenderingEngine::get_instance()->setupTopLevelWindow(PROJECT_NAME_C);
+	
 	/*
 		This changes the minimum allowed number of vertices in a VBO.
 		Default is 500.

src/client/renderingengine.cpp

@@ -43,6 +43,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #ifdef XORG_USED
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
+#include <X11/Xatom.h>
 #endif
 
 #ifdef __ANDROID__
@@ -186,23 +187,119 @@ bool RenderingEngine::print_video_modes()
 	return videomode_list != NULL;
 }
 
-void RenderingEngine::setXorgClassHint(
-		const video::SExposedVideoData &video_data, const std::string &name)
+bool RenderingEngine::setupTopLevelWindow(const std::string &name)
+{
+	// FIXME: It would make more sense for there to be a switch of some
+	// sort here that would call the correct toplevel setup methods for
+	// the environment Minetest is running in but for now not deviating
+	// from the original pattern.
+	
+	/* Setting Xorg properties for the top level window */
+	setupTopLevelXorgWindow(name);
+	/* Done with Xorg properties */
+
+	/* Setting general properties for the top level window */
+	verbosestream << "Client: Configuring general top level"
+		<< " window properties"
+		<< std::endl;
+
+	bool result = setWindowIcon();
+
+	verbosestream << "Client: Finished configuring general top level"
+		<< " window properties"
+		<< std::endl;
+	/* Done with general properties */
+
+	// FIXME: setWindowIcon returns a bool result but it is unused.
+	// For now continue to return this result. 
+	return result;
+}
+
+void RenderingEngine::setupTopLevelXorgWindow(const std::string &name)
 {
 #ifdef XORG_USED
-	if (video_data.OpenGLLinux.X11Display == NULL)
+	const video::SExposedVideoData exposedData = driver->getExposedVideoData();
+
+	Display *x11_dpl = reinterpret_cast<Display *>(exposedData.OpenGLLinux.X11Display);
+	if (x11_dpl == NULL) {
+		warningstream << "Client: Could not find X11 Display in ExposedVideoData"
+			<< std::endl; 
 		return;
+	}
 
+	verbosestream << "Client: Configuring Xorg specific top level"
+		<< " window properties"
+		<< std::endl;
+
+
+	Window x11_win = reinterpret_cast<Window>(exposedData.OpenGLLinux.X11Window);
+
+	// Set application name and class hints. For now name and class are the same.
 	XClassHint *classhint = XAllocClassHint();
-	classhint->res_name = (char *)name.c_str();
-	classhint->res_class = (char *)name.c_str();
+	classhint->res_name = const_cast<char *>(name.c_str());
+	classhint->res_class = const_cast<char *>(name.c_str());
 
-	XSetClassHint((Display *)video_data.OpenGLLinux.X11Display,
-			video_data.OpenGLLinux.X11Window, classhint);
+	XSetClassHint(x11_dpl, x11_win, classhint);
 	XFree(classhint);
+
+	// FIXME: In the future WMNormalHints should be set ... e.g see the
+	// gtk/gdk code (gdk/x11/gdksurface-x11.c) for the setup_top_level
+	// method. But for now (as it would require some significant changes) 
+	// leave the code as is. 
+	
+	// The following is borrowed from the above gdk source for setting top
+	// level windows. The source indicates and the Xlib docs suggest that
+	// this will set the WM_CLIENT_MACHINE and WM_LOCAL_NAME. This will not 
+	// set the WM_CLIENT_MACHINE to a Fully Qualified Domain Name (FQDN) which is 
+	// required by the Extended Window Manager Hints (EWMH) spec when setting
+	// the _NET_WM_PID (see further down) but running Minetest in an env
+	// where the window manager is on another machine from Minetest (therefore
+	// making the PID useless) is not expected to be a problem. Further
+	// more, using gtk/gdk as the model it would seem that not using a FQDN is
+	// not an issue for modern Xorg window managers.
+	
+	verbosestream << "Client: Setting Xorg window manager Properties"
+		<< std::endl;
+
+	XSetWMProperties (x11_dpl, x11_win, NULL, NULL, NULL, 0, NULL, NULL, NULL);
+
+	// Set the _NET_WM_PID window property according to the EWMH spec. _NET_WM_PID 
+	// (in conjunction with WM_CLIENT_MACHINE) can be used by window managers to 
+	// force a shutdown of an application if it doesn't respond to the destroy 
+	// window message. 
+    
+	verbosestream << "Client: Setting Xorg _NET_WM_PID extened window manager property"
+		<< std::endl;
+
+	Atom NET_WM_PID = XInternAtom(x11_dpl, "_NET_WM_PID", false);
+
+	pid_t pid = getpid();
+	infostream << "Client: PID is '" << static_cast<long>(pid) << "'"
+		<< std::endl;
+
+	XChangeProperty(x11_dpl, x11_win, NET_WM_PID, 
+			XA_CARDINAL, 32, PropModeReplace, 
+			reinterpret_cast<unsigned char *>(&pid),1);
+
+	// Set the WM_CLIENT_LEADER window property here. Minetest has only one
+	// window and that window will always be the leader. 
+
+	verbosestream << "Client: Setting Xorg WM_CLIENT_LEADER property"
+		<< std::endl;
+
+	Atom WM_CLIENT_LEADER = XInternAtom(x11_dpl, "WM_CLIENT_LEADER", false);
+
+	XChangeProperty (x11_dpl, x11_win, WM_CLIENT_LEADER,
+		XA_WINDOW, 32, PropModeReplace,
+		reinterpret_cast<unsigned char *>(&x11_win), 1);
+
+	verbosestream << "Client: Finished configuring Xorg specific top level"
+		<< " window properties"
+		<< std::endl;
 #endif
 }
 
+
 bool RenderingEngine::setWindowIcon()
 {
 #if defined(XORG_USED)

src/client/renderingengine.h

@@ -51,8 +51,8 @@ public:
 	static float getDisplayDensity();
 	static v2u32 getDisplaySize();
 
-	static void setXorgClassHint(const video::SExposedVideoData &video_data,
-			const std::string &name);
+	bool setupTopLevelWindow(const std::string &name);
+	void setupTopLevelXorgWindow(const std::string &name);
 	bool setWindowIcon();
 	bool setXorgWindowIconFromPath(const std::string &icon_file);
 	static bool print_video_modes();