From d3860d6ce9c0d55b416b294cff6be67f734d9b84 Mon Sep 17 00:00:00 2001
From: Gregory Heytings <gregory@heytings.org>
Date: Sun, 24 Oct 2021 15:08:31 +0000
Subject: [PATCH] Option to stop emacs server when it has no clients anymore.

* lisp/server.el (server-stop-when-no-clients): New function.
* doc/emacs/misc.texi (Emacs Server): Document the new function,
and mention that an Emacs server can be started with emacsclient.
---
 doc/emacs/misc.texi | 10 ++++++++++
 lisp/server.el      |  9 +++++++++
 2 files changed, 19 insertions(+)

diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi
index 810d212021..a68632831a 100644
--- a/doc/emacs/misc.texi
+++ b/doc/emacs/misc.texi
@@ -1697,6 +1697,11 @@ Emacs Server
 calls @code{server-start} after initialization and does not open an
 initial frame.  It then waits for edit requests from clients.
 
+@item
+Run the command @code{emacsclient} with the @samp{--alternate-editor=""}
+command-line option.  This starts an Emacs daemon only if no Emacs daemon
+is already running.
+
 @cindex systemd unit file
 @item
 If your operating system uses @command{systemd} to manage startup,
@@ -1763,6 +1768,11 @@ Emacs Server
   emacs --daemon=foo
 @end example
 
+@findex server-stop-when-no-clients
+  If you want to automatically stop the Emacs server when it has no
+clients anymore, put the expression @code{(server-stop-when-no-clients)}
+in your init file (@pxref{Init File}).
+
 @findex server-eval-at
   If you have defined a server by a unique server name, it is possible
 to connect to the server from another Emacs instance and evaluate Lisp
diff --git a/lisp/server.el b/lisp/server.el
index 6359a76199..fb1cb886e1 100644
--- a/lisp/server.el
+++ b/lisp/server.el
@@ -1746,6 +1746,15 @@ server-save-buffers-kill-terminal
 	     (server-delete-client proc)))
 	  (t (error "Invalid client frame")))))
 
+;;;###autoload
+(defun server-stop-when-no-clients ()
+  "Automatically stop server when it has no remaining clients.
+This function is meant to be put in init files."
+  (when (daemonp)
+    (run-with-timer 10 2 (lambda ()
+                          (unless (cdr (frame-list))
+                            (save-buffers-kill-emacs))))))
+
 (define-key ctl-x-map "#" 'server-edit)
 
 (defun server-unload-function ()
-- 
2.33.0