about summary refs log tree commit diff
path: root/tools/emacs-pkgs/nix-util/nix-util.el
blob: 533e7e6f34c9f6742c940e7b9d3fca9d465919c4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
;;; nix-util.el --- Utilities for dealing with Nix code. -*- lexical-binding: t; -*-
;;
;; Copyright (C) 2019 Google Inc.
;;
;; Author: Vincent Ambo <tazjin@google.com>
;; Version: 1.0
;; Package-Requires: (json map)
;;
;;; Commentary:
;;
;; This package adds some functionality that I find useful when
;; working in Nix buffers.

(require 'json)
(require 'map)

(defun nix/prefetch-github (owner repo) ; TODO(tazjin): support different branches
  "Fetch the master branch of a GitHub repository and insert the
  call to `fetchFromGitHub' at point."

  (interactive "sOwner: \nsRepository: ")

  (let* (;; Keep these vars around for output insertion
         (point (point))
         (buffer (current-buffer))
         (name (concat "github-fetcher/" owner "/" repo))
         (outbuf (format "*%s*" name))
         (errbuf (get-buffer-create "*github-fetcher/errors*"))
         (cleanup (lambda ()
                    (kill-buffer outbuf)
                    (kill-buffer errbuf)
                    (with-current-buffer buffer
                      (read-only-mode -1))))
         (prefetch-handler
          (lambda (_process event)
            (unwind-protect
                (pcase event
                  ("finished\n"
                   (let* ((json-string (with-current-buffer outbuf
                                         (buffer-string)))
                          (result (json-parse-string json-string)))
                     (with-current-buffer buffer
                       (goto-char point)
                       (map-let (("rev" rev) ("sha256" sha256)) result
                         (read-only-mode -1)
                         (insert (format "fetchFromGitHub {
  owner = \"%s\";
  repo = \"%s\";
  rev = \"%s\";
  sha256 = \"%s\";
};" owner repo rev sha256))
                         (indent-region point (point))))))
                  (_ (with-current-buffer errbuf
                       (error "Failed to prefetch %s/%s: %s"
                              owner repo (buffer-string)))))
              (funcall cleanup)))))

    ;; Fetching happens asynchronously, but we'd like to make sure the
    ;; point stays in place while that happens.
    (read-only-mode)
    (make-process :name name
                  :buffer outbuf
                  :command `("nix-prefetch-github" ,owner ,repo)
                  :stderr errbuf
                  :sentinel prefetch-handler)))

(provide 'nix-util)