From 8712090b23f31ed9719a928e67612bb9e478e8a2 Mon Sep 17 00:00:00 2001
From: dakkar <dakkar@thenautilus.net>
Date: Sat, 10 Apr 2021 13:12:22 +0100
Subject: better: cope with inhibitor *disconnecting*

DBus can tell us when someone disconnects from the bus, so we react to
that
---
 xscreensaver-dbus | 50 ++++++++++++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/xscreensaver-dbus b/xscreensaver-dbus
index 002c0d9..b7e8a30 100755
--- a/xscreensaver-dbus
+++ b/xscreensaver-dbus
@@ -156,29 +156,26 @@ package Saver {
             ),
         );
 
+        $self->dbus_obj->connect_to_signal(
+            'NameOwnerChanged',
+            $self->curry::weak::name_owner_changed,
+        );
+
         return;
     }
 
     sub inhibit($self,$name,$reason,$message) {
-        my $sender_pid = try {
-            return $self->dbus_obj->GetConnectionUnixProcessID(
-                $message->get_sender,
-            );
-        } catch {
-            $log->warning('problems getting PID of inhibitor',{error=>$_});
-            return undef;
-        };
-
         my $cookie;
         do {
             $cookie = int(rand(2**31))
         } until !exists $self->_inhibits->{$cookie};
 
-        $self->_inhibits->{$cookie} = [ $name, $reason, $sender_pid ];
+        my $sender = $message->get_sender;
+        $self->_inhibits->{$cookie} = [ $name, $reason, $sender ];
 
         $log->debugf(
-            '<%s> stops screensaver for <%s> (cookie %d) - %d active',
-            $name, $reason, $cookie, scalar(keys $self->_inhibits->%*),
+            '<%s> (%s) stops screensaver for <%s> (cookie %d) - %d active',
+            $name, $sender, $reason, $cookie, scalar(keys $self->_inhibits->%*),
         );
         $self->reactor->toggle_timeout($self->_prod_id, 1);
 
@@ -188,11 +185,12 @@ package Saver {
     sub uninhibit($self,$cookie,$message) {
         my $inhibit = delete $self->_inhibits->{$cookie}
             or return;
-        my ($name, $reason, $sender_pid) = @$inhibit;
+        my ($name, $reason, $sender) = @$inhibit;
+        my $this_sender = $message->get_sender;
 
         $log->debugf(
-            '<%s> resumed screensaver for <%s> (cookie %d) - %d left',
-            $name, $reason, $cookie, scalar(keys $self->_inhibits->%*),
+            '<%s> (was %s, is %s) resumed screensaver for <%s> (cookie %d) - %d left',
+            $name, $sender, $this_sender, $reason, $cookie, scalar(keys $self->_inhibits->%*),
         );
 
         $self->reactor->toggle_timeout($self->_prod_id, 0)
@@ -201,24 +199,32 @@ package Saver {
         return;
     }
 
-    sub prod_screensaver($self) {
+    sub name_owner_changed($self,$bus_name,$old,$new) {
+        $log->tracef('<%s> changed from <%s> to <%s>',
+                     $bus_name, $old, $new);
+
         for my $cookie (sort keys $self->_inhibits->%*) {
-            my ($name, $reason, $sender_pid) = @{$self->_inhibits->{$cookie}};
-            next if kill 0, $sender_pid;
-            # uh oh, caller is dead
+            my ($name, $reason, $sender) = @{$self->_inhibits->{$cookie}};
+            # is this inhibit from that bus name?
+            next unless $sender && $sender eq $bus_name;
+            # did the bus owner just disconnect?
+            next unless $old && !$new;
+
+            # if so, remove the inhibit
             my $inhibit = delete $self->_inhibits->{$cookie};
 
             $log->debugf(
-                '<%s> is dead (it stopped screensaver for <%s>, cookie %d) - %d left',
-                $name, $reason, $cookie, scalar(keys $self->_inhibits->%*),
+                '<%s> (%s) disconnected from the bus (it stopped screensaver for <%s>, cookie %d) - %d left',
+                $name, $bus_name, $reason, $cookie, scalar(keys $self->_inhibits->%*),
             );
         }
 
         unless ($self->_inhibits->%*) {
             $self->reactor->toggle_timeout($self->_prod_id, 0);
-            return;
         }
+    }
 
+    sub prod_screensaver($self) {
         $log->debug('prodding xscreensaver');
         system(qw(xscreensaver-command -deactivate));
     }
-- 
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