perf(emacs): add emacs-lsp-booster

Author: gekoke

flake.lock

@@ -38,6 +38,9 @@
     spicetify-nix.inputs.nixpkgs.follows = "nixpkgs";
 
     nixos-wsl.url = "github:nix-community/NixOS-WSL/main";
+
+    emacs-lsp-booster.url = "github:slotThe/emacs-lsp-booster-flake";
+    emacs-lsp-booster.inputs.nixpkgs.follows = "nixpkgs";
   };
 
   outputs =

flake.nix

@@ -2,6 +2,7 @@
   config,
   lib,
   pkgs,
+  inputs,
   ...
 }:
 with lib;
@@ -70,6 +71,8 @@ in
         ripgrep
         # magit-delta
         delta
+        # LSP
+        inputs.emacs-lsp-booster.packages.${pkgs.system}.default
         # lsp-nix
         nil
         nixfmt-rfc-style

modules/nixos/programs/emacs/default.nix

@@ -791,6 +791,38 @@
                                                #'cape-file
                                                #'cape-dabbrev
                                                #'cape-keyword)))
+
+  (defun lsp-booster--advice-json-parse (old-fn &rest args)
+    "Try to parse bytecode instead of json."
+    (or
+     (when (equal (following-char) ?#)
+       (let ((bytecode (read (current-buffer))))
+         (when (byte-code-function-p bytecode)
+           (funcall bytecode))))
+     (apply old-fn args)))
+  (advice-add (if (progn (require 'json)
+                         (fboundp 'json-parse-buffer))
+                  'json-parse-buffer
+                'json-read)
+              :around
+              #'lsp-booster--advice-json-parse)
+
+  (defun lsp-booster--advice-final-command (old-fn cmd &optional test?)
+    "Prepend emacs-lsp-booster command to lsp CMD."
+    (let ((orig-result (funcall old-fn cmd test?)))
+      (if (and (not test?)                             ;; for check lsp-server-present?
+               (not (file-remote-p default-directory)) ;; see lsp-resolve-final-command, it would add extra shell wrapper
+               lsp-use-plists
+               (not (functionp 'json-rpc-connection))  ;; native json-rpc
+               (executable-find "emacs-lsp-booster"))
+          (progn
+            (when-let ((command-from-exec-path (executable-find (car orig-result))))  ;; resolve command from exec-path (in case not found in $PATH)
+              (setcar orig-result command-from-exec-path))
+            (message "Using emacs-lsp-booster for %s!" orig-result)
+            (cons "emacs-lsp-booster" orig-result))
+        orig-result)))
+
+  (advice-add 'lsp-resolve-final-command :around #'lsp-booster--advice-final-command)
   :hook
   (lsp-mode . lsp-enable-which-key-integration)
   (lsp-mode . yas-minor-mode)