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early-init.el
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early-init.el
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;;; early-init.el -*- lexical-binding: t; -*-
;;; Commentary:
;;
;; early-init.el was introduced in Emacs 27.1 and is loaded before init.el;
;; before Emacs initializes package.el and its UI; and before site files are
;; loaded. This is the best time to tweak Emacs (though any UI work will have to
;; be deferred).
;;
;; This file is responsible for bootstrapping an interactive session, and is
;; where all our dirtiest (and config-agnostic) startup hacks should live. It's
;; also home to Doom's bootloader, which lets you choose what Emacs config to
;; load with one of two switches:
;; - '--init-directory DIR' (backported from Emacs 29)
;; - Or Doom's profile system with '--profile NAME' (you declare configs in
;; $EMACSDIR/profiles.el or implicitly as directories in $EMACSDIR/profiles/).
;;
;; You should *never* load this file in non-interactive sessions (e.g. batch
;; scripts). Load `core-start' or use 'doom run' instead!
;;
;;; Code:
;; Garbage collection is a big contributor to startup times. This fends it off,
;; then is reset later by enabling `gcmh-mode'. Not resetting it will cause
;; stuttering/freezes.
(setq gc-cons-threshold most-positive-fixnum)
;; Prioritize old byte-compiled source files over newer sources. It saves us a
;; little IO time to skip all the mtime checks on each lookup.
(setq load-prefer-newer nil)
(unless (or (daemonp)
init-file-debug)
(let ((old-file-name-handler-alist file-name-handler-alist))
;; `file-name-handler-alist' is consulted on each `require', `load' and
;; various path/io functions. You get a minor speed up by unsetting this.
;; Some warning, however: this could cause problems on builds of Emacs where
;; its site lisp files aren't byte-compiled and we're forced to load the
;; *.el.gz files (e.g. on Alpine).
(setq-default file-name-handler-alist nil)
;; ...but restore `file-name-handler-alist' later, because it is needed for
;; handling encrypted or compressed files, among other things.
(defun doom-reset-file-handler-alist-h ()
(setq file-name-handler-alist
;; Merge instead of overwrite because there may have bene changes to
;; `file-name-handler-alist' since startup we want to preserve.
(delete-dups (append file-name-handler-alist
old-file-name-handler-alist))))
(add-hook 'emacs-startup-hook #'doom-reset-file-handler-alist-h 101))
;; Premature redisplays can substantially affect startup times and produce
;; ugly flashes of unstyled Emacs.
(setq-default inhibit-redisplay t
inhibit-message t)
(add-hook 'window-setup-hook
(lambda ()
(setq-default inhibit-redisplay nil
inhibit-message nil)
(redisplay)))
;; Site files tend to use `load-file', which emits "Loading X..." messages in
;; the echo area, which in turn triggers a redisplay. Redisplays can have a
;; substantial effect on startup times and in this case happens so early that
;; Emacs may flash white while starting up.
(define-advice load-file (:override (file) silence)
(load file nil :nomessage))
;; Undo our `load-file' advice above, to limit the scope of any edge cases it
;; may introduce down the road.
(define-advice startup--load-user-init-file (:before (&rest _) init-doom)
(advice-remove #'load-file #'load-file@silence)))
;;
;;; Detect `user-emacs-directory'
;; Prevent recursive profile processing, in case you're loading a Doom profile.
(unless (boundp 'doom-version)
;; Not using `command-switch-alist' to process --profile and --init-directory
;; was intentional. `command-switch-alist' is processed too late at startup to
;; change `user-emacs-directory' in time.
;; DEPRECATED Backported from 29. Remove this when 27/28 support is removed.
(let ((initdir (or (cadr (member "--init-directory" command-line-args))
(getenv-internal "EMACSDIR"))))
(when initdir
;; Discard the switch to prevent "invalid option" errors later.
(add-to-list 'command-switch-alist (cons "--init-directory" (lambda (_) (pop argv))))
(setq user-emacs-directory initdir)))
(let ((profile (or (cadr (member "--profile" command-line-args))
(getenv-internal "DOOMPROFILE"))))
(when profile
;; Discard the switch to prevent "invalid option" errors later.
(add-to-list 'command-switch-alist (cons "--profile" (lambda (_) (pop argv))))
;; While processing the requested profile, Doom loosely expects
;; `user-emacs-directory' to be changed. If it doesn't, then you're using
;; profiles.el as a glorified, runtime dir-locals.el (which is fine, if
;; intended).
(catch 'found
(let ((profiles-file (expand-file-name "profiles.el" user-emacs-directory)))
(when (file-exists-p profiles-file)
(with-temp-buffer
(let ((coding-system-for-read 'utf-8-auto))
(insert-file-contents profiles-file))
(condition-case-unless-debug e
(let ((profile-data (cdr (assq (intern profile) (read (current-buffer))))))
(dolist (var profile-data (if profile-data (throw 'found t)))
(if (eq var 'env)
(dolist (env var) (setenv (car env) (cdr env)))
(set (car var) (cdr var)))))
(error (error "Failed to parse profiles.el: %s" (error-message-string e))))))
;; If the requested profile isn't in profiles.el, then see if
;; $EMACSDIR/profiles/$DOOMPROFILE exists. These are implicit
;; profiles, where `emacs --profile foo` will be equivalent to `emacs
;; --init-directory $EMACSDIR/profile/foo', if that directory exists.
(let ((profile-dir
(expand-file-name
profile (or (getenv-internal "DOOMPROFILESDIR")
(expand-file-name "profiles/" user-emacs-directory)))))
(when (file-directory-p profile-dir)
(setq user-emacs-directory profile-dir)
(throw 'found t)))
(user-error "No %S profile found" profile))))))
;;
;;; Bootstrap
;; Let er rip
(let (init-file)
;; Load the heart of Doom Emacs
(if (load (expand-file-name "core/core" user-emacs-directory) t t)
;; ...and prepare it for an interactive session.
(setq init-file (expand-file-name "core-start" doom-core-dir))
;; ...but if that fails, then this is likely not a Doom config.
(setq early-init-file (expand-file-name "early-init" user-emacs-directory))
(load early-init-file t t))
;; We hijack Emacs' initfile resolver to inject our own entry point. Why do
;; this? Because:
;;
;; - It spares Emacs the effort of looking for/loading useless initfiles, like
;; ~/.emacs and ~/_emacs. And skips ~/.emacs.d/init.el, which won't exist if
;; you're using Doom (fyi: doom hackers or chemacs users could then use
;; $EMACSDIR as their $DOOMDIR, if they wanted).
;; - Later, 'doom sync' will dynamically generate its bootstrap file, which
;; will be important for Doom's profile system later. Until then, we'll use
;; core/core-start.el.
;; - A "fallback" initfile can be trivially specified, in case the
;; bootstrapper is missing (if the user hasn't run 'doom sync' or is a
;; first-timer). This is an opportunity to display a "safe mode" environment
;; that's less intimidating and more helpful than the broken state errors
;; would've left Emacs in, otherwise.
;; - A generated config allows for a file IO optimized startup.
(define-advice startup--load-user-init-file (:filter-args (args) init-doom)
"Initialize Doom Emacs in an interactive session."
(list (lambda ()
(or init-file
(expand-file-name "init.el" user-emacs-directory)))
nil ; TODO Replace with safe mode initfile
(caddr args))))
;;; early-init.el ends here