core/pkgs/build-support/emacs/buffer.nix
2024-06-30 09:12:46 +01:00

93 lines
4 KiB
Nix

# Functions to build elisp files to locally configure emcas buffers.
# See https://github.com/shlevy/nix-buffer
{
lib,
writeText,
inherit-local,
}:
rec {
withPackages =
pkgs':
let
pkgs = builtins.filter (x: x != null) pkgs';
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 &optional ibh)
(if (and nixpkgs--is-nixpkgs-buffer (eq (aref name 0) ?\s))
(let ((buf (funcall orig name ibh)))
(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 ibh)))
(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: "\"${p}/bin\"") pkgs)
}) exec-path))
(inherit-local-permanent eshell-path-env (concat "${lib.makeSearchPath "bin" pkgs}:" (if (boundp 'eshell-path-env) eshell-path-env (getenv "PATH"))))
(setq nixpkgs--is-nixpkgs-buffer t)
(inherit-local 'nixpkgs--is-nixpkgs-buffer)
${lib.concatStringsSep "\n" extras}
'';
# nix-buffer function for a project with a bunch of haskell packages
# in one directory
haskellMonoRepo =
{
project-root, # The monorepo root
haskellPackages, # The composed haskell packages set that contains all of the packages
}:
{ root }:
let
# The haskell paths.
haskell-paths = lib.filesystem.haskellPathsInDir project-root;
# Find the haskell package that the 'root' is in, if any.
haskell-path-parent =
let
filtered = builtins.filter (
name: lib.hasPrefix (toString (project-root + "/${name}")) (toString root)
) (builtins.attrNames haskell-paths);
in
if filtered == [ ] then null else builtins.head filtered;
# We're in the directory of a haskell package
is-haskell-package = haskell-path-parent != null;
haskell-package = haskellPackages.${haskell-path-parent};
# GHC environment with all needed deps for the haskell package
haskell-package-env = builtins.head haskell-package.env.nativeBuildInputs;
in
lib.optionalAttrs is-haskell-package (withPackages [ haskell-package-env ]);
}