[elpa] externals/ement 79e8cc51f1 5/5: Fix: (ement-notify) Ensure D-Bus is available

[ELPA Syncer]

branch: externals/ement
commit 79e8cc51f104b35246e73c434a024f5635ddca5f
Author: Adam Porter <adam@alphapapa.net>
Commit: Adam Porter <adam@alphapapa.net>

    Fix: (ement-notify) Ensure D-Bus is available
    
    Adds (ement-notify-dbus-p).
    
    Fixes #83.  Thanks to Tassilo Horn (@tsdh) for reporting and providing
    the predicate code.
    
    Reported-by: Tassilo Horn <tsdh@gnu.org>
    Suggested-by: Tassilo Horn <tsdh@gnu.org>
    Co-authored-by: Tassilo Horn <tsdh@gnu.org>
---
 README.org      |  1 +
 ement-notify.el | 15 +++++++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/README.org b/README.org
index 62ea2ab0af..dae3b70e17 100644
--- a/README.org
+++ b/README.org
@@ -264,6 +264,7 @@ Note that, while ~matrix-client~ remains usable, and 
probably will for some time
 
 *Fixed*
 + Function ~ement-room-sync~ correctly updates room-list buffers.  (Thanks to 
[[https://github.com/vizs][Visuwesh]].)
++ Only send D-Bus notifications when supported.  (Fixes 
[[https://github.com/alphapapa/ement.el/issues/83][#83]].  Thanks to 
[[https://github.com/tsdh][Tassilo Horn]].)
 
 ** 0.1.1
 
diff --git a/ement-notify.el b/ement-notify.el
index 6107531cdf..2b0016021d 100644
--- a/ement-notify.el
+++ b/ement-notify.el
@@ -48,6 +48,13 @@
     (make-composed-keymap (list map button-buffer-map) 'view-mode-map))
   "Map for Ement notification buffers.")
 
+(defvar ement-notify-dbus-p
+  (and (featurep 'dbusbind)
+       (require 'dbus nil :no-error)
+       (dbus-ignore-errors (dbus-get-unique-name :session))
+       (dbus-ping :session "org.freedesktop.Notifications"))
+  "Whether D-Bus notifications are usable.")
+
 ;;;; Customization
 
 (defgroup ement-notify nil
@@ -160,13 +167,13 @@ margins in Emacs.  But it's useful, anyway."
 
 (defun ement-notify (event room session)
   "Send notifications for EVENT in ROOM on SESSION.
-Calls functions in `ement-notify-functions' if all of
-`ement-notify-ignore-predicates' return nil.  Does not do
-anything if session hasn't finished initial sync."
+Sends if all of `ement-notify-ignore-predicates' return nil.
+Does not do anything if session hasn't finished initial sync."
   (when (and (ement-session-has-synced-p session)
              (cl-loop for pred in ement-notify-ignore-predicates
                       never (funcall pred event room session)))
-    (when (run-hook-with-args-until-success 
'ement-notify-notification-predicates event room session)
+    (when (and ement-notify-dbus-p
+               (run-hook-with-args-until-success 
'ement-notify-notification-predicates event room session))
       (ement-notify--notifications-notify event room session))
     (when (run-hook-with-args-until-success 'ement-notify-log-predicates event 
room session)
       (ement-notify--log-to-buffer event room session))