[PATCH] Implement custom grab key combination definition

[Michal Novotny <minovotn redhat com>]

Hi all,
I'm working in virtualization and I'm using virt-manager and virt-viewer 
tools to see the domain's VNC window where the grab key is defined to be 
"Ctrl + Alt". Since this configuration is not that good in some cases 
(since "Ctrl+Alt" could be defined for anything else in the window 
manager) this patch allows you to set the grab key combination in the 
running GTK-VNC application. I did work on this one in my spare time 
since I think this is a useful feature to be implemented. At least I've 
learned how to use GTK in C language if you won't apply the patch.

Technically 2 new functions have been added to do the job, 
vnc_display_set_grab_keys() and vnc_display_get_grab_keys() with the old 
definition to "Ctrl+Alt" preserved by default.

Please note that the gvncviewer.c and gvncviewer.py codes have been 
changed to use both of the functions and the definition can be modifiers 
only, or now even modifiers in combination with some key, i.e. something 
like: "Ctrl+Alt+[F]" or "Ctrl+Alt+[F|f]". The brackets are important 
since they specify the character or set of 2 characters to be used with 
the modifiers combination to trigger the grab and they have to be at the 
end of the expression. When 2 characters, delimited by logical "or" (|) 
are there, it means that the expression is being matched by either of 
them therefore you can specify both uppercase and lowercase letters here 
to the expression or make possibility of 2 different keys with the 
expression like "Ctrl+Alt+[a|b]" to match both 'a' and 'b' keys with the 
Control and Alt modifiers pressed.

Tested and working fine as cloned from git://git.gnome.org/gtk-vnc and 
this patch is applicable to the current git tree from this git URL on 
Fedora-13 (Goddard) with virt-manager/virt-viewer and gvncviewer 
examples in the tree.

I hope it will be helpful and merged to the git tree. If any suggestions 
please write both to my e-mail with CC to the gtk-vnc list.

Thanks,
Michal

--
Michal Novotny<minovotn redhat com>, RHCE
Virtualization Team (xen userspace), Red Hat

commit 4f39be84f6adf55896ea3bb5cbdc81dee075bb8e
Author: Michal Novotny <minovotn redhat com>
Date:   Fri Jun 4 01:43:50 2010 +0200

    Implement custom grab key combination definition
    
    This is the patch to implement custom grab key combination definition
    support. The new functions {get|set}_grab_keys has been introduced in
    this patch. Definition can be done either for modifier keys (e.g.
    "Ctrl + Alt") or some key could be added to the modifiers, e.g.
    "Ctrl + Alt + [F]". Please note the brackets in the definition which
    is necessary to specify a character or an alternative character using
    "Ctrl + Alt + [F|f]" which allows you to define both uppercase and
    lowercase letters or two printable letters to grab the VNC window.
    
    Please note that only the printable letters can be put into those
    brackets and no function keys [F1 - F12] or any others yet.
    
    Signed-off-by: Michal Novotny <minovotn redhat com>

diff --git a/examples/gvncviewer.c b/examples/gvncviewer.c
index c3fbd74..058ea77 100644
--- a/examples/gvncviewer.c
+++ b/examples/gvncviewer.c
@@ -48,12 +48,13 @@ static void set_title(VncDisplay *vncdisplay, GtkWidget *window,
 {
 	const char *name;
 	char title[1024];
-	const char *subtitle;
+	char subtitle[512];
 
 	if (grabbed)
-		subtitle = "(Press Ctrl+Alt to release pointer) ";
+		snprintf(subtitle, 512, "(Press %s to release pointer) ",
+                     vnc_display_get_grab_keys(VNC_DISPLAY(vncdisplay)));
 	else
-		subtitle = "";
+		memset(subtitle, 0, 512);
 
 	name = vnc_display_get_name(VNC_DISPLAY(vncdisplay));
 	snprintf(title, sizeof(title), "%s%s - GVncViewer",
@@ -467,6 +468,8 @@ int main(int argc, char **argv)
 	vnc_display_set_keyboard_grab(VNC_DISPLAY(vnc), TRUE);
 	vnc_display_set_pointer_grab(VNC_DISPLAY(vnc), TRUE);
 
+        vnc_display_set_grab_keys(VNC_DISPLAY(vnc), "Ctrl+Alt+[F|f]");
+
 	if (!gtk_widget_is_composited(window)) {
 		vnc_display_set_scaling(VNC_DISPLAY(vnc), TRUE);
 		gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(scaling), TRUE);
diff --git a/examples/gvncviewer.py b/examples/gvncviewer.py
old mode 100644
new mode 100755
index 9a74268..0572309
--- a/examples/gvncviewer.py
+++ b/examples/gvncviewer.py
@@ -29,7 +29,7 @@ if len(sys.argv) != 2 and len(sys.argv) != 3:
 def set_title(vnc, window, grabbed):
     name = vnc.get_name()
     if grabbed:
-        subtitle = "(Press Ctrl+Alt to release pointer) "
+        subtitle = "(Press %s to release pointer) " % vnc.get_grab_keys()
     else:
         subtitle = ""
 
@@ -173,6 +173,8 @@ layout.add(vnc)
 vnc.realize()
 vnc.set_pointer_grab(True)
 vnc.set_keyboard_grab(True)
+# Example to define "Ctrl+Alt+F" or "Ctrl+Alt+f" as a grab key combo
+vnc.set_grab_keys("Ctrl+Alt+[F|f]")
 #v.set_pointer_local(True)
 
 if len(sys.argv) == 3:
diff --git a/src/libgtk-vnc_sym.version b/src/libgtk-vnc_sym.version
index b6f5347..41bcf21 100644
--- a/src/libgtk-vnc_sym.version
+++ b/src/libgtk-vnc_sym.version
@@ -68,6 +68,10 @@
     vnc_image_framebuffer_new;
     vnc_image_framebuffer_get_image;
 
+# grab key settings support
+    vnc_display_set_grab_keys;
+    vnc_display_get_grab_keys;
+
   local:
       *;
 };
diff --git a/src/vncdisplay.c b/src/vncdisplay.c
index a031125..960b43c 100644
--- a/src/vncdisplay.c
+++ b/src/vncdisplay.c
@@ -44,6 +44,8 @@
 #include <winsock2.h>
 #endif
 
+#define VNC_DEFAULT_GRAB_KEYS "Ctrl+Alt"
+
 static void winsock_startup (void);
 static void winsock_cleanup (void);
 
@@ -85,6 +87,13 @@ struct _VncDisplayPrivate
 
 	GSList *preferable_auths;
 	const guint8 const *keycode_map;
+
+        /* Variables for the grab key */
+        gchar *grab_key_combo;
+        guint grab_key;
+        guint grab_key_alt;
+        guint grab_key_modifiers;
+        guint _grab_key_mod;
 };
 
 G_DEFINE_TYPE(VncDisplay, vnc_display, GTK_TYPE_DRAWING_AREA)
@@ -95,6 +104,7 @@ enum
   PROP_0,
   PROP_POINTER_LOCAL,
   PROP_POINTER_GRAB,
+  PROP_GRAB_KEYS,
   PROP_KEYBOARD_GRAB,
   PROP_READ_ONLY,
   PROP_WIDTH,
@@ -162,6 +172,9 @@ vnc_display_get_property (GObject    *object,
 
   switch (prop_id)
     {
+      case PROP_GRAB_KEYS:
+        g_value_set_string(value, vnc->priv->grab_key_combo);
+        break;
       case PROP_POINTER_LOCAL:
         g_value_set_boolean (value, vnc->priv->local_pointer);
 	break;
@@ -220,6 +233,9 @@ vnc_display_set_property (GObject      *object,
       case PROP_POINTER_GRAB:
         vnc_display_set_pointer_grab (vnc, g_value_get_boolean (value));
         break;
+      case PROP_GRAB_KEYS:
+        vnc_display_set_grab_keys (vnc, g_value_get_string (value));
+        break;
       case PROP_KEYBOARD_GRAB:
         vnc_display_set_keyboard_grab (vnc, g_value_get_boolean (value));
         break;
@@ -673,6 +689,93 @@ static gboolean motion_event(GtkWidget *widget, GdkEventMotion *motion)
 	return TRUE;
 }
 
+#define KEY_MOD_CTRL	0x01
+#define KEY_MOD_ALT	0x02
+#define KEY_MOD_SHIFT	0x04
+#define KEY_MOD_SUPER	0x08
+#define KEY_MOD_HYPER	0x16
+
+static void update_grab_keys(VncDisplay *obj)
+{
+        VncDisplayPrivate *priv = obj->priv;
+        guint mod, len;
+
+        if ((len = strlen(priv->grab_key_combo)) < 3)
+            return;
+
+        mod = 0;
+        if (strstr(priv->grab_key_combo, "Ctrl") != NULL)
+            mod |= KEY_MOD_CTRL;
+        if (strstr(priv->grab_key_combo, "Alt") != NULL)
+            mod |= KEY_MOD_ALT;
+        if (strstr(priv->grab_key_combo, "Shift") != NULL)
+            mod |= KEY_MOD_SHIFT;
+        if (strstr(priv->grab_key_combo, "Super") != NULL)
+            mod |= KEY_MOD_SUPER;
+        if (strstr(priv->grab_key_combo, "Hyper") != NULL)
+            mod |= KEY_MOD_HYPER;
+
+        priv->grab_key_modifiers = mod;
+
+        if ((priv->grab_key_combo[ len - 3 ] == '[')
+           && (priv->grab_key_combo[ len - 1 ] == ']'))
+           priv->grab_key = priv->grab_key_combo[ len - 2 ];
+
+        if ((priv->grab_key_combo[ len - 5 ] == '[')
+           && (priv->grab_key_combo[ len - 3 ] == '|')
+           && (priv->grab_key_combo[ len - 1 ] == ']')) {
+           priv->grab_key = priv->grab_key_combo[ len - 4 ];
+           priv->grab_key_alt = priv->grab_key_combo[ len - 2 ];
+        }
+}
+
+static gboolean check_for_grab_key(GtkWidget *widget, int type, int keyval)
+{
+        VncDisplayPrivate *priv = VNC_DISPLAY(widget)->priv;
+        int val;
+
+        switch (keyval) {
+            case GDK_Control_L:
+            case GDK_Control_R:
+                 val = KEY_MOD_CTRL;
+                 break;
+            case GDK_Alt_L:
+            case GDK_Alt_R:
+                 val = KEY_MOD_ALT;
+                 break;
+            case GDK_Shift_L:
+            case GDK_Shift_R:
+                 val = KEY_MOD_SHIFT;
+                 break;
+            case GDK_Super_L:
+            case GDK_Super_R:
+                 val = KEY_MOD_SUPER;
+                 break;
+            case GDK_Hyper_L:
+            case GDK_Hyper_R:
+                 val = KEY_MOD_HYPER;
+                 break;
+            default:
+                 val = 0;
+                 break;
+        }
+
+        if (val) {
+            if (priv->_grab_key_mod & val)
+                priv->_grab_key_mod -= val;
+            else
+                priv->_grab_key_mod |= val;
+        }
+
+        if ((priv->_grab_key_mod == priv->grab_key_modifiers)
+           && (((keyval == priv->grab_key) || (keyval == priv->grab_key_alt))
+               || ((priv->grab_key == 0) && (priv->grab_key_alt == 0)))
+           && (type == GDK_KEY_PRESS))
+            return TRUE;
+
+        return FALSE;
+}
+
 static gboolean key_event(GtkWidget *widget, GdkEventKey *key)
 {
 	VncDisplayPrivate *priv = VNC_DISPLAY(widget)->priv;
@@ -752,9 +855,7 @@ static gboolean key_event(GtkWidget *widget, GdkEventKey *key)
 		}
 	}
 
-	if (key->type == GDK_KEY_PRESS &&
-	    ((keyval == GDK_Control_L && (key->state & GDK_MOD1_MASK)) ||
-	     (keyval == GDK_Alt_L && (key->state & GDK_CONTROL_MASK)))) {
+	if (check_for_grab_key(widget, key->type, key->keyval)) {
 		if (priv->in_pointer_grab)
 			do_pointer_ungrab(VNC_DISPLAY(widget), FALSE);
 		else if (!priv->grab_keyboard || !priv->absolute)
@@ -1817,6 +1918,8 @@ static void vnc_display_init(VncDisplay *display)
 	priv->shared_flag = FALSE;
 	priv->force_size = TRUE;
 
+	vnc_display_set_grab_keys(display, VNC_DEFAULT_GRAB_KEYS);
+
 	/*
 	 * Both these two provide TLS based auth, and can layer
 	 * all the other auth types on top. So these two must
@@ -1898,6 +2001,19 @@ void vnc_display_set_pointer_grab(VncDisplay *obj, gboolean enable)
 		do_pointer_ungrab(obj, FALSE);
 }
 
+void vnc_display_set_grab_keys(VncDisplay *obj, const gchar *key_combo)
+{
+        VncDisplayPrivate *priv = obj->priv;
+
+        priv->grab_key_combo = (gchar *)key_combo;
+        update_grab_keys(obj);
+}
+
+const gchar *vnc_display_get_grab_keys(VncDisplay *obj)
+{
+        return obj->priv->grab_key_combo;
+}
+
 void vnc_display_set_keyboard_grab(VncDisplay *obj, gboolean enable)
 {
 	VncDisplayPrivate *priv = obj->priv;
diff --git a/src/vncdisplay.h b/src/vncdisplay.h
index 1b5b297..1f00f5b 100644
--- a/src/vncdisplay.h
+++ b/src/vncdisplay.h
@@ -94,6 +94,8 @@ void            vnc_display_send_keys_ex(VncDisplay *obj, const guint *keyvals,
 					 int nkeyvals, VncDisplayKeyEvent kind);
 
 void		vnc_display_send_pointer(VncDisplay *obj, gint x, gint y, int button_mask);
+void		vnc_display_set_grab_keys(VncDisplay *obj, const gchar *key_combo);
+const gchar*	vnc_display_get_grab_keys(VncDisplay *obj);
 
 gboolean	vnc_display_set_credential(VncDisplay *obj, int type, const gchar *data);