helm-occur for org headers

gistfile1.el

;;; helm in org

(defclass keu-helm-source-multi-occur-org-headers (helm-source-multi-occur)
  ((search :initform '(keu-helm-occur-org-headers-search))
;   (search-strict :initform t)
   (matchplugin :initform nil)))

;; Mimic of helm-occur.  IT IS A MIMIC!
(defun keu-helm-occur-org-headers ()
  "helm-occur for org headers."
  (interactive)
  (helm-occur-init-source)
  ;; Terrible!
  (let1 helm-source-occur (helm-make-source "Occur org headers" 'keu-helm-source-multi-occur-org-headers)
    (let ((bufs (list (buffer-name (current-buffer)))))
      (helm-attrset 'moccur-buffers bufs helm-source-occur)
      (helm-set-local-variable 'helm-multi-occur-buffer-list bufs)
      (helm-set-local-variable
       'helm-multi-occur-buffer-tick
       (cl-loop for b in bufs
                collect (buffer-chars-modified-tick (get-buffer b)))))
    (helm :sources (list helm-source-occur)
          :buffer "*helm occur*"
          :history 'helm-grep-history
          :preselect (and (memq 'helm-source-occur helm-sources-using-default-as-input)
                          (format "%s:%d:\t" (buffer-name) (line-number-at-pos (point))))
          :truncate-lines t)))

(defun keu-helm-occur-org-headers-search (pattern)
  (helm-candidates-in-buffer-search-default-fn (concat "^\\*+ .*" pattern)))