Implement "show current thread only"

[balta2ar]

From org-mode I miss a command to collapse all threads but the current one. For example:
before:

a
  a1
    a11
b
  b1
    b11 <-- cursor is here, we press "collapse-all-but-this-thread"
    b22
      b222
      b223
c
  c1
    c11

after

a -- collapsed
b
  b1
    b11 <-- cursor is still here
    b22 -- collapsed
c -- collapsed

in org-mode it's implemented as follows (from my config):

(defun ded/org-show-current-heading-tidily ()
  "Show next entry, keeping other entries closed."
  (interactive)
  (if (save-excursion (end-of-line) (outline-invisible-p))
      (progn (org-show-entry) (show-children))
    (outline-back-to-heading)
    (unless (and (bolp) (org-on-heading-p))
      (org-up-heading-safe)
      (hide-subtree)
      (error "Boundary reached"))
    (org-overview)
    (org-reveal t)
    (org-show-entry)
    (recenter-top-bottom)
    (show-children)
    (recenter-top-bottom)))
(global-set-key (kbd "M-o") 'ded/org-show-current-heading-tidily)