feat(literate): add async config tangling

modules/config/literate/autoload.el

@@ -9,6 +9,9 @@
   "The file path that `+literate-config-file' will be tangled to, then
 byte-compiled from.")
 
+(defvar +literate-tangle--async-proc nil)
+(defvar +literate-tangle--async-proc-start-time nil)
+
 (defvar org-mode-hook)
 (defvar org-inhibit-startup)
 
@@ -16,6 +19,73 @@ byte-compiled from.")
 
 ;;;###autoload
 (defun +literate-tangle-h ()
+  "Tangles `+literate-config-file' if it has changed.
+This is performed with an asyncronous Emacs process, except when
+`doom-interactive-p' is non-nil."
+  (if doom-interactive-p
+      (+literate-tangle--async)
+    (+literate-tangle--sync)))
+
+(defun +literate-tangle--async ()
+  "Tangles `+literate-config-file' using an async Emacs process."
+  (unless (getenv "__NOTANGLE")
+    (let ((default-directory doom-private-dir)
+          (target +literate-config-file)
+          (cache +literate-config-cache-file)
+          (dest (expand-file-name (concat doom-module-config-file ".el"))))
+      (when +literate-tangle--async-proc
+        (message "Killing outdated tangle process...")
+        (set-process-sentinel +literate-tangle--async-proc #'ignore)
+        (kill-process +literate-tangle--async-proc)
+        (sit-for 0.3)) ; ensure the message is seen for a bit
+      (setq +literate-tangle--async-proc-start-time (float-time)
+            +literate-tangle--async-proc
+            ;; See `+literate-tangle--sync' for an explanation of the (progn ...) below.
+            (start-process "tangle-config"
+                           (get-buffer-create " *tangle config*")
+                           "emacs" "--batch" "--eval"
+                           (format "(progn \
+(require 'ox) \
+(require 'ob-tangle) \
+(setq org-startup-indented nil \
+      org-startup-folded nil \
+      vc-handled-backends nil \
+      write-file-functions nil \
+      before-save-hook nil \
+      after-save-hook nil \
+      org-mode-hook nil \
+      org-inhibit-startup t \
+      org-confirm-babel-evaluate nil) \
+(org-babel-tangle-file %S %S) \
+(with-temp-file %S) \
+)" target dest cache)))
+      (set-process-sentinel +literate-tangle--async-proc #'+literate-tangle--async-sentinel)
+      (run-at-time nil nil (lambda () (message "Tangling config.org"))) ; ensure shown after a save message
+      "Tangling config.org...")))
+
+(defun +literate-tangle--async-sentinel (process signal)
+  (cond
+   ((and (eq 'exit (process-status process))
+         (= 0 (process-exit-status process)))
+    (message "Tangled config.org sucessfully (took %.1fs)"
+             (- (float-time) +literate-tangle--async-proc-start-time))
+    (setq +literate-tangle--async-proc nil))
+   ((memq (process-status process) (list 'exit 'signal))
+    (pop-to-buffer (get-buffer " *tangle config*"))
+    (message "Failed to tangle config.org (after %.1fs)"
+             (- (float-time) +literate-tangle--async-proc-start-time))
+    (setq +literate-tangle--async-proc nil))))
+
+(defun +literate-tangle-check-finished ()
+  "When a tangle is still in progress, ask the user if they want to wait for it."
+  (when (and (process-live-p +literate-tangle--async-proc)
+             (yes-or-no-p "Config is currently retangling, would you please wait a few seconds?"))
+    (switch-to-buffer " *tangle config*")
+    (signal 'quit nil)))
+
+(add-hook! 'kill-emacs-hook #'+literate-tangle-check-finished)
+
+(defun +literate-tangle--sync ()
   "Tangles `+literate-config-file' if it has changed."
   (and (not (getenv "__NOTANGLE"))
        (require 'ox nil t)