Implement `interrupt-process-functions'

* lisp/net/tramp.el (tramp-interrupt-process): Rename from
`tramp-advice-interrupt-process'.  Adapt according to changed API.
(top): Add it to `interrupt-process-functions'.

* src/process.c (Finternal_default_interrupt_process): New defun.
(Finterrupt_process): Change implementation, based on
Vinterrupt_process_functions.
(Vinterrupt_process_functions): New defvar.

* test/lisp/net/tramp-tests.el (tramp-test40-unload): Do not
test removal of advice.

1 files changed, 28 insertions, 25 deletions

diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 3469d45ff2a..2aa9a6b9859 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -4381,33 +4381,36 @@ Only works for Bourne-like shells."
 ;;; Signal handling.  This works for remote processes, which have set
 ;;; the process property `remote-pid'.
 
-(defun tramp-advice-interrupt-process (orig-fun &rest args)
+(defun tramp-interrupt-process (&optional process _current-group)
   "Interrupt remote process PROC."
-  (let* ((arg0 (car args))
-         (proc (cond
-                ((processp arg0) arg0)
-                ((bufferp arg0)  (get-buffer-process arg0))
-                ((stringp arg0)  (or (get-process arg0)
-                                     (get-buffer-process arg0)))
-                ((null arg0)     (get-buffer-process (current-buffer)))
-                (t               arg0)))
-         pid)
+  ;; CURRENT-GROUP is not implemented yet.
+  (let ((proc (cond
+               ((processp process) process)
+               ((bufferp process)  (get-buffer-process process))
+               ((stringp process)  (or (get-process process)
+                                       (get-buffer-process process)))
+               ((null process)     (get-buffer-process (current-buffer)))
+               (t                  process)))
+        pid)
     ;; If it's a Tramp process, send the INT signal remotely.
-    (if (and (processp proc)
-             (setq pid (process-get proc 'remote-pid)))
-        (progn
-          (tramp-message proc 5 "%s %s" proc pid)
-          (tramp-send-command
-           (tramp-get-connection-property proc "vector" nil)
-           (format "kill -2 %d" pid)))
-      ;; Otherwise, just run the original function.
-      (apply orig-fun args))))
-
-(advice-add 'interrupt-process :around 'tramp-advice-interrupt-process)
-(add-hook
- 'tramp-unload-hook
- (lambda ()
-   (advice-remove 'interrupt-process 'tramp-advice-interrupt-process)))
+    (when (and (processp proc)
+               (setq pid (process-get proc 'remote-pid)))
+      (tramp-message proc 5 "Interrupt process %s with pid %s" proc pid)
+      ;; This is for tramp-sh.el.  Other backends do not support this (yet).
+      (tramp-compat-funcall
+       'tramp-send-command
+       (tramp-get-connection-property proc "vector" nil)
+       (format "kill -2 %d" pid))
+      ;; Report success.
+      proc)))
+
+;; `interrupt-process-functions' exists since Emacs 26.1.
+(when (boundp 'interrupt-process-functions)
+  (add-hook 'interrupt-process-functions 'tramp-interrupt-process)
+  (add-hook
+   'tramp-unload-hook
+   (lambda ()
+     (remove-hook 'interrupt-process-functions 'tramp-interrupt-process))))
 
 ;;; Integration of eshell.el: