From 6ec3026e510d7e9440e8d0cbe206ef68a8e4251a Mon Sep 17 00:00:00 2001
From: Robert Helgesson <robert@rycee.net>
Date: Sun, 15 Jan 2017 10:46:20 +0100
Subject: [PATCH] xsession: improve initialization script

This adds a `graphical-session-pre` target for things that need to run
just before the main session starts. Also adds a loop during shutdown
that waits until all deactivating units are gone. Inspired by
<https://youtu.be/hq18daxTkLA>.
---
 modules/xsession.nix | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/modules/xsession.nix b/modules/xsession.nix
index 52393c7fb..3b36a5b53 100644
--- a/modules/xsession.nix
+++ b/modules/xsession.nix
@@ -53,6 +53,14 @@ in
       };
     };
 
+    # For stuff that needs to start just before a graphical session
+    # starts.
+    systemd.user.targets.graphical-session-pre = {
+      Unit = {
+        Description = "Pre-graphical session";
+      };
+    };
+
     # A basic graphical session target. Apparently this will come
     # standard in future Systemd versions.
     systemd.user.targets.graphical-session = {
@@ -73,13 +81,21 @@ in
         systemctl --user import-environment XAUTHORITY
         systemctl --user import-environment XDG_DATA_DIRS
         systemctl --user import-environment XDG_RUNTIME_DIR
-        systemctl --user start graphical-session.target
+
+        systemctl --user restart graphical-session-pre.target
+        systemctl --user restart graphical-session.target
 
         ${cfg.initExtra}
 
         ${cfg.windowManager}
 
         systemctl --user stop graphical-session.target
+        systemctl --user stop graphical-session-pre.target
+
+        # Wait until the units actually stop.
+        while [[ -n "$(systemctl --user --no-legend --state=deactivating list-units)" ]]; do
+          sleep 0.5
+        done
       '';
     };
   };