melpautil.el

;; a packagelet for figuring out where melpa is.  will move point to commit in magit-log buffers.
(defun melpautil-where-is-melpa (package &optional force-refresh)
  (interactive (list (intern (let-alist (magithub-repo) .name))
                     current-prefix-arg))
  (let ((commit (melpautil-commit-for-package package force-refresh)))
    (unless commit
      (error "Commit not found"))
    (setq commit (magit-rev-parse "--short" commit))
    (when (derived-mode-p 'magit-log-mode)
      (goto-char 0)
      (while (not (string= commit (magit-section-value (magit-current-section))))
        (magit-section-forward-sibling)))
    (message "MELPA is at %s" (magit-get-shortname commit))))

(defconst melpautil-archive-url "http://melpa.org/archive.json")
(defvar melpautil-archive nil)
(defun melpautil--get-archive (refresh-now)
  (let ((now (current-time))
        (archive-url ))
    (cdr (if (or (null melpautil-archive)
                 refresh-now
                 ;; auto refresh every five minutes
                 (< 300 (time-to-seconds (time-subtract now (car melpautil-archive)))))
             (setq melpautil-archive
                   (cons now (with-current-buffer (url-retrieve-synchronously melpautil-archive-url)
                               (search-forward "\n\n")
                               (json-read))))
           melpautil-archive))))

(defun melpautil-commit-for-package (package &optional refresh-now)
  (let-alist (alist-get package (melpautil--get-archive refresh-now))
    .props.commit))