Safeguard against calling gdk_x11_window_get_xid with a NULL GdkWindow

[rcaridade145]

This pull request aims to fix #692

[zhuyaliang]

The source code format should be maintained

[rcaridade145]

Replace tabs with spaces.

[raveit65]

Thank you, this looks better, now a review can started.

[zhuyaliang]

@rcaridade145 I think we only need to add three lines of code, so that the modification of the existing code is the least

       if (ok1 && popup_widget != NULL)
         {
+          GdkWindow * window=gtk_widget_get_window (popup_widget);
+          if (window == NULL)
+              return FALSE;
           Window popup_xid = gdk_x11_window_get_xid (gtk_widget_get_window (popup_widget));

           gboolean ok2 = XTranslateCoordinates (display->xdisplay,

Of course, there is no problem with your code. I will respect your code style

[rcaridade145]

https://hackerchick.com/religious-war-48293-single-vs-multiple/ I prefer a single one.

[zhuyaliang]

@rcaridade145 OK, but the code format needs to be modified and some spaces need to be added

[tormodvolden]

The established code style in this file is to use early, multiple returns when possible, instead of else clauses and the extra indentation it entails. IMO consistent code style is more important than individual developer preference.

[rcaridade145]

Will change the code.

[tormodvolden]

The whitespace police will arrest you for window=gtk_widget_get_window. It can also be argued that all declarations such as Window popup_xid should be at the start of the block and not intermixed with statements.

[rcaridade145]

I've added spaces.

[raveit65]

@zhuyaliang When 2 or 3 reviewers (with you) did approved a normal PR, it is save to merge. Everybody from the team is allowed to do that....

[raveit65]

@rcaridade145 Another code-formatting issue of your small change with 4 lines of code. https://github.com/mate-desktop/marco/commit/a905a4d11aa25be55bbe3b22d9c7b23b46a50e0c

[tormodvolden]

To everybody's defense such trailing whitespace doesn't not show up in Github's web view, they seem to strip it off. Bad Github. But as a tip, it does show up (in red) with "git diff" before the commit and with "git show" before you push the commit anywhere.