nixpkgs/pkgs/build-support/emacs/buffer.nix

52 lines
2.6 KiB
Nix

# Functions to build elisp files to locally configure emcas buffers.
# See https://github.com/shlevy/nix-buffer
{ lib, writeText, inherit-local }:
{
withPackages = pkgs: let
extras = map (x: x.emacsBufferSetup pkgs) (builtins.filter (builtins.hasAttr "emacsBufferSetup") pkgs);
in writeText "dir-locals.el" ''
(require 'inherit-local "${inherit-local}/share/emacs/site-lisp/elpa/inherit-local-${inherit-local.version}/inherit-local.elc")
; Only set up nixpkgs buffer handling when we have some buffers active
(defvar nixpkgs--buffer-count 0)
(when (eq nixpkgs--buffer-count 0)
(make-variable-buffer-local 'nixpkgs--is-nixpkgs-buffer)
; When generating a new temporary buffer (one whose name starts with a space), do inherit-local inheritance and make it a nixpkgs buffer
(defun nixpkgs--around-generate (orig name)
(if (and nixpkgs--is-nixpkgs-buffer (eq (aref name 0) ?\s))
(let ((buf (funcall orig name)))
(progn
(inherit-local-inherit-child buf)
(with-current-buffer buf
(setq nixpkgs--buffer-count (1+ nixpkgs--buffer-count))
(add-hook 'kill-buffer-hook 'nixpkgs--decrement-buffer-count nil t)))
buf)
(funcall orig name)))
(advice-add 'generate-new-buffer :around #'nixpkgs--around-generate)
; When we have no more nixpkgs buffers, tear down the buffer handling
(defun nixpkgs--decrement-buffer-count ()
(setq nixpkgs--buffer-count (1- nixpkgs--buffer-count))
(when (eq nixpkgs--buffer-count 0)
(advice-remove 'generate-new-buffer #'nixpkgs--around-generate)
(fmakunbound 'nixpkgs--around-generate)
(fmakunbound 'nixpkgs--decrement-buffer-count))))
(setq nixpkgs--buffer-count (1+ nixpkgs--buffer-count))
(add-hook 'kill-buffer-hook 'nixpkgs--decrement-buffer-count nil t)
; Add packages to PATH and exec-path
(make-local-variable 'process-environment)
(put 'process-environment 'permanent-local t)
(inherit-local 'process-environment)
; setenv modifies in place, so copy the environment first
(setq process-environment (copy-tree process-environment))
(setenv "PATH" (concat "${lib.makeSearchPath "bin" pkgs}:" (getenv "PATH")))
(inherit-local-permanent exec-path (append '(${builtins.concatStringsSep " " (map (p: "\"${p}/bin\"") pkgs)}) exec-path))
(setq nixpkgs--is-nixpkgs-buffer t)
(inherit-local 'nixpkgs--is-nixpkgs-buffer)
${lib.concatStringsSep "\n" extras}
'';
}