feat: Add :defer-incrementally

Adds org-mode module for the sake of testing it.
2025-01-15 16:56:12 -07:00
parent f08870dbc9
commit 3ecff5e898
5 changed files with 137 additions and 2 deletions
--- a/users/crumb/programs/emacs/modules/syd-use-package.el
+++ b/users/crumb/programs/emacs/modules/syd-use-package.el
@@ -0,0 +1,105 @@
+;;; syd-use-package.el -*- lexical-binding: t; -*-
+
+(defvar syd-incremental-idle-timer 0.75
+  "How long (in idle seconds) in between incrementally loading packages.")
+
+(defvar syd-incremental-first-idle-timer (if (daemonp) 0 2.0)
+  "How long (in idle seconds) until incremental loading starts.
+
+Set this to nil to disable incremental loading at startup.
+Set this to 0 to load all incrementally deferred packages immediately at
+`after-init-hook'.")
+
+(defvar syd-incremental-packages '(t)
+  "A list of packages to load incrementally after startup. Any large packages
+here may cause noticeable pauses, so it's recommended you break them up into
+sub-packages. For example, `org' is comprised of many packages, and might be
+broken up into:
+
+  (syd-load-packages-incrementally
+   '(calendar find-func format-spec org-macs org-compat
+     org-faces org-entities org-list org-pcomplete org-src
+     org-footnote org-macro ob org org-clock org-agenda
+     org-capture))
+
+This is already done by the lang/org module, however.
+
+If you want to disable incremental loading altogether, either remove
+`syd-load-packages-incrementally-h' from `after-init-hook' or set
+`syd-incremental-first-idle-timer' to nil. Incremental loading does not occur
+in daemon sessions (they are loaded immediately at startup).")
+
+(defun syd-load-packages-incrementally (packages &optional now)
+  "Registers PACKAGES to be loaded incrementally.
+
+If NOW is non-nil, PACKAGES will be marked for incremental loading next time
+Emacs is idle for `syd-incremental-first-idle-timer' seconds (falls back to
+`syd-incremental-idle-timer'), then in `syd-incremental-idle-timer' intervals
+afterwards."
+  (let* ((gc-cons-threshold most-positive-fixnum)
+         (first-idle-timer (or syd-incremental-first-idle-timer
+                               syd-incremental-idle-timer)))
+    (if (not now)
+        (cl-callf append syd-incremental-packages packages)
+      (while packages
+        (let ((req (pop packages))
+              idle-time)
+          (unless (featurep req)
+            (condition-case-unless-debug e
+                (and
+                 (or (null (setq idle-time (current-idle-time)))
+                     (< (float-time idle-time) first-idle-timer)
+                     (not
+                      (while-no-input
+                        ;; If `default-directory' doesn't exist or is
+                        ;; unreadable, Emacs throws file errors.
+                        (let ((default-directory user-emacs-directory)
+                              (inhibit-message t)
+                              (file-name-handler-alist
+                               (list (rassq 'jka-compr-handler file-name-handler-alist))))
+                          (message "loading %s" req)
+                          (require req nil t)
+                          t))))
+                 (push req packages))
+              (error
+               (message "Error: failed to incrementally load %S because: %s" req e)
+               (setq packages nil)))
+            (unless (null packages)
+              (run-at-time (if idle-time
+                               syd-incremental-idle-timer
+                             first-idle-timer)
+                           nil #'syd-load-packages-incrementally
+                           packages t)
+              (setq packages nil))))))))
+
+(defun syd-load-packages-incrementally-h ()
+  "Begin incrementally loading packages in `syd-incremental-packages'.
+
+If this is a daemon session, load them all immediately instead."
+  (when (numberp syd-incremental-first-idle-timer)
+    (if (zerop syd-incremental-first-idle-timer)
+        (mapc #'require (cdr syd-incremental-packages))
+      (run-with-idle-timer syd-incremental-first-idle-timer
+                           nil #'syd-load-packages-incrementally
+                           (cdr syd-incremental-packages) t))))
+
+(unless noninteractive
+  (add-hook 'after-init-hook #'syd-load-packages-incrementally-h 100))
+
+(with-eval-after-load 'use-package-core
+  (push :defer-incrementally use-package-deferring-keywords)
+  (setq use-package-keywords (use-package-list-insert
+                              :defer-incrementally use-package-keywords :after))
+  (defalias 'use-package-normalize/:defer-incrementally
+    #'use-package-normalize-symlist)
+  (defun use-package-handler/:defer-incrementally
+      (name _keyword targets rest state)
+    (use-package-concat
+     `((syd-load-packages-incrementally
+        ',(if (equal targets '(t))
+              (list name)
+            (append targets (list name)))))
+     (use-package-process-keywords name rest state))))
+
+(provide 'syd-use-package)
+;;; syd-use-package.el ends here