bug#43252: 27.1; DBus properties lack type hints or overrides

[Hugh Daschbach <hugh@ccss.com>]

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Michael Albinus writes:

> Hugh Daschbach <hugh@ccss.com> writes:
>
> Hi Hugh,
>
> I've pushed a fix to master, which shall solve the 
> problem. Playing with
> introspection, I found the problem that it stalls if there are 
> no
> introspection data. Not applicable. So I've turned to the 
> alternative
> approach, allowing type symbols in `dbus-set-property' and
> `dbus-register-property'. You could call now
>
> (dbus-register-property :session "org.gnu.Emacs" "/node1"
>  "org.bluez.GattService1" "Device" :readwrite
>  :object-path "/path/node1")
>
> Similar in `dbus-set-property'. Documentation is adapted, 
> dbus-tests.el
> extended accordingly.

Thanks, Michael.  I think I still have issues.

The attached script generates two boolean properties, then issues 
a
GetManagedObjects method call.  The two properties are not 
returned,
though they are in the registered objects table.

The script also drops an elisp ‘dbus-get-all-managed-objects’ 
request in
the *scratch* buffer.  If I execute that, I get a similar failure 
to
#43251.  That may not be surprising.

I’m working an a more comprehensive test that registers the 
variety of
types I need to support.  I’ll post that when I have something 
worth
looking at.  I’d like to present that in a form compatible with
dbus-test.el rather than throw more one off scripts at you.  So 
give me
a bit.

I think the mechanism you implemented works well for simple types. 
Is
there a mechanism to specify the signature for an empty compound 
type?
I need arrays and dictionaries of various types.

For something like a byte array, I expect I’ll need to interleave 
the
:byte type between each value in the array.  Correct?

Thanks,
Hugh


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;;; register-property-test.el --- Test program for complex :dict-entry.  -*- lexical-binding: t; -*-

;; Copyright (C) 2020  Hugh Daschbach

;; Author: Hugh Daschbach <hugh@ccss.com>
;; Keywords: tools

;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; This program demonstrates an error in handling D-Bus properties
;; interface.
;;

;;; Code:

(require 'dbus)
(dbus-register-service :system "org.gnu.Emacs")

(defun main ()
  (interactive)
  (setq dbus-debug t)
  (setq debug-on-error t)

  ;; Boolean

  (dbus-register-property :system "org.gnu.Emacs"
                          "/org/gnu/Emacs/hci0/dev_45_6d_61_63_73_01/service0002/characteristic0003"
                          "org.bluez.GattCharacteristic1"
                          "Discoverable-untyped" :read nil t)

  (dbus-register-property :system "org.gnu.Emacs"
                          "/org/gnu/Emacs/hci0/dev_45_6d_61_63_73_01/service0002/characteristic0003"
                          "org.bluez.GattCharacteristic1"
                          "Discoverable-typed" :read :boolean nil t)
  
  (sit-for 1)
  (start-process "gmo" "*GMO*"
                  "dbus-send"
                  "--system"
                  "--print-reply"
                  "--type=method_call"
                  "--system"
                  "--dest=org.gnu.Emacs"
                  "/"
                  "org.freedesktop.DBus.ObjectManager.GetManagedObjects")
  (switch-to-buffer "*scratch*")
  (insert "(pp (dbus-get-all-managed-objects :system \"org.gnu.Emacs\" \"/\"))\n")
  (sit-for 1)
  (split-window-right)
  (switch-to-buffer "*GMO*")
  (goto-char (point-min)))

(provide 'register-property-test)

;;; register-property-test.el ends here