[PATCH 2/2] shell: grab the parent popup when a sub popup window is deleted or hidden

[Giulio Camuffo]

If the client opens a popup menu and submenu, when it closes or hides the
submenu the pointer grab should return to the parent menu.
---
 src/shell.c | 42 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/src/shell.c b/src/shell.c
index 345ca8e..008fcef 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -182,6 +182,7 @@ struct shell_surface {
 		int32_t initial_up;
 		struct wl_seat *seat;
 		uint32_t serial;
+		struct shell_surface *prev;
 	} popup;
 
 	struct {
@@ -1899,6 +1900,7 @@ shell_map_popup(struct shell_surface *shsurf)
 	struct wl_seat *seat = shsurf->popup.seat;
 	struct weston_surface *es = shsurf->surface;
 	struct weston_surface *parent = shsurf->parent;
+	struct shell_surface *popup_parent;
 
 	/* Remove the old transform. We don't want to add it twice
 	 * otherwise Weston will go into an infinite loop when going
@@ -1932,9 +1934,25 @@ shell_map_popup(struct shell_surface *shsurf)
 	weston_surface_set_position(es, shsurf->popup.x, shsurf->popup.y);
 	weston_surface_update_transform(es);
 
+	if (seat->pointer->grab->interface == &popup_grab_interface)
+		popup_parent = container_of(seat->pointer->grab,
+				      struct shell_surface, popup.grab);
+	else
+		popup_parent = NULL;
+
 	/* We don't require the grab to still be active, but if another
 	 * grab has started in the meantime, we end the popup now. */
-	if (seat->pointer->grab_serial == shsurf->popup.serial) {
+
+	/* Need to make sure here that a sub-popup doesn't trigger the
+	 * send_popup_done case.  And we need to set the popup.prev
+	 * pointer.  We can look at seat->pointer->grab.interface to
+	 * see if it's &popup_grab_interface and if it is use
+	 * container_of on seat->pointer->grab to get back to the
+	 * shsurf. */
+
+	if (seat->pointer->grab_serial == shsurf->popup.serial ||
+		(popup_parent && popup_parent->resource.client == shsurf->resource.client)) {
+		shsurf->popup.prev = popup_parent;
 		wl_pointer_start_grab(seat->pointer, &shsurf->popup.grab);
 	} else {
 		wl_shell_surface_send_popup_done(&shsurf->resource);
@@ -1973,10 +1991,22 @@ static const struct wl_shell_surface_interface shell_surface_implementation = {
 };
 
 static void
+grab_parent_popup(struct shell_surface *shsurf)
+{
+	wl_pointer_end_grab(shsurf->popup.grab.pointer);
+	struct shell_surface *parent = shsurf->popup.prev;
+	if (shsurf->popup.prev != NULL) {
+		wl_pointer_start_grab(parent->popup.seat->pointer, &parent->popup.grab);
+	}
+}
+
+static void
 destroy_shell_surface(struct shell_surface *shsurf)
 {
-	if (shsurf->popup.grab.pointer)
-		wl_pointer_end_grab(shsurf->popup.grab.pointer);
+	/* If this surface has a parent popup, grab it. */
+	if (shsurf->popup.grab.pointer) {
+		grab_parent_popup(shsurf);
+	}
 
 	if (shsurf->fullscreen.type == WL_SHELL_SURFACE_FULLSCREEN_METHOD_DRIVER &&
 	    shell_surface_is_top_fullscreen(shsurf)) {
@@ -3098,6 +3128,12 @@ shell_surface_configure(struct weston_surface *es, int32_t sx, int32_t sy)
 	struct shell_surface *shsurf = get_shell_surface(es);
 	struct desktop_shell *shell = shsurf->shell;
 
+	/* If this surface has just been unmapped and we have a parent popup,
+	 * grab it. */
+	if (es->pending.remove_contents && shsurf->popup.grab.pointer) {
+		grab_parent_popup(shsurf);
+	}
+
 	if (!es->buffer_ref.buffer)
 		return;
 
-- 
1.8.1.3