From 4079a2a4644be890845daaa5df867fcdc5bed2ab Mon Sep 17 00:00:00 2001
From: Pierre Neidhardt <mail@ambrevar.xyz>
Date: Tue, 15 Dec 2020 11:32:38 +0100
Subject: [PATCH] Helm: Allow C-c C-x to open multiple files.

---
 .emacs.d/lisp/init-helm.el  |  2 +
 .emacs.d/lisp/patch-helm.el | 91 +++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 .emacs.d/lisp/patch-helm.el

diff --git a/.emacs.d/lisp/init-helm.el b/.emacs.d/lisp/init-helm.el
index a396a65a..013f0755 100644
--- a/.emacs.d/lisp/init-helm.el
+++ b/.emacs.d/lisp/init-helm.el
@@ -367,6 +367,8 @@ Useful for Guix."
 (defmethod helm-setup-user-source ((source helm-moccur-class))
   (setf (slot-value source 'action-transformer) 'helm-occur-action-transformer))
 
+(require 'patch-helm)
+
 (when (require 'helm-switch-to-repl nil :noerror)
   (helm-switch-to-repl-setup))
 
diff --git a/.emacs.d/lisp/patch-helm.el b/.emacs.d/lisp/patch-helm.el
new file mode 100644
index 00000000..5516857b
--- /dev/null
+++ b/.emacs.d/lisp/patch-helm.el
@@ -0,0 +1,91 @@
+(defun ambrevar/helm-run-or-raise (exe &optional files)
+  "Run asynchronously EXE or jump to the application window.
+If EXE is already running just jump to his window if
+`helm-raise-command' is non-nil.
+When FILE argument is provided run EXE with FILE."
+  (let* ((real-com (car (split-string exe)))
+         (proc     (if files
+                       (concat real-com " " (mapconcat #'identity files " "))
+                     real-com))
+         process-connection-type)
+    (if (get-process proc)
+        (if helm-raise-command
+            (shell-command  (format helm-raise-command real-com))
+          (error "Error: %s is already running" real-com))
+      (when (member real-com helm-external-commands-list)
+        (message "Starting %s..." real-com)
+        (if files
+            (start-process-shell-command
+             proc nil (format "%s %s"
+                              real-com
+                              (mapconcat
+                               (lambda (file)
+                                 (shell-quote-argument
+                                  (if (eq system-type 'windows-nt)
+                                      (helm-w32-prepare-filename file)
+                                    (expand-file-name file))))
+                               files " ")))
+          (start-process-shell-command proc nil real-com))
+        (set-process-sentinel
+         (get-process proc)
+         (lambda (process event)
+             (when (and (string= event "finished\n")
+                        helm-raise-command
+                        (not (helm-get-pid-from-process-name real-com)))
+               (shell-command  (format helm-raise-command "emacs")))
+             (message "%s process...Finished." process))))
+      (setq helm-external-commands-list
+            (cons real-com
+                  (delete real-com helm-external-commands-list))))))
+
+;; This change was rejected upstream.
+(defun ambrevar/helm-open-file-externally (_file)
+  "Open FILE with an external program.
+Try to guess which program to use with
+`helm-get-default-program-for-file'.
+If not found or a prefix arg is given query the user which tool
+to use."
+  (let* ((fname      (expand-file-name (car (helm-marked-candidates))))
+         (collection (helm-external-commands-list-1 'sort))
+         (def-prog   (helm-get-default-program-for-file fname))
+         (program    (if (or helm-current-prefix-arg (not def-prog))
+                         ;; Prefix arg or no default program.
+                         (prog1
+                             (helm-comp-read
+                              "Program: " collection
+                              :must-match t
+                              :name "Open file Externally"
+                              :del-input nil
+                              :history helm-external-command-history)
+                           ;; Always prompt to set this program as default.
+                           (setq def-prog nil))
+                         ;; No prefix arg or default program exists.
+                         def-prog)))
+    (unless (or def-prog ; Association exists, no need to record it.
+                ;; Don't try to record non--filenames associations (e.g urls).
+                (not (file-exists-p fname)))
+      (when
+          (y-or-n-p
+           (format
+            "Do you want to make `%s' the default program for this kind of files? "
+            program))
+        (helm-aif (assoc (file-name-extension fname)
+                         helm-external-programs-associations)
+            (setq helm-external-programs-associations
+                  (delete it helm-external-programs-associations)))
+        (push (cons (file-name-extension fname)
+                    (helm-read-string
+                     "Program (Add args maybe and confirm): " program))
+              helm-external-programs-associations)
+        (customize-save-variable 'helm-external-programs-associations
+                                 helm-external-programs-associations)))
+    (ambrevar/helm-run-or-raise program (helm-marked-candidates))
+    (setq helm-external-command-history
+          (cons program
+                (delete program
+                        (cl-loop for i in helm-external-command-history
+                              when (executable-find i) collect i))))))
+
+(advice-add 'helm-open-file-externally :override 'ambrevar/helm-open-file-externally)
+
+(provide 'patch-helm)