Update tabbar when nothing to save - emacs

Question

I'm using tab-bar to tabify my work in Emacs, and so far I found tabbar-ruler that basically adds an indicator to show when a file is modified.
It doesn't work by itself, apparently.
I added some pieces of code that let tabbar know the file is modified,
but it doesn't work when I revert my work.
I need some hook, if possible, to let emacs know that upon reaching a "don't have to save" state, it will udpate the tabbar.
This is the code so far:
(defadvice tabbar-buffer-tab-label (after fixup_tab_label_space_and_flag activate)
(setq ad-return-value
(if (and (buffer-modified-p (tabbar-tab-value tab))
(buffer-file-name (tabbar-tab-value tab)))
(concat " " (concat ad-return-value " "))
(concat " " (concat ad-return-value " ")))))
;; Called each time the modification state of the buffer changed.
(defun er/modification-state-change ()
(tabbar-set-template tabbar-current-tabset nil)
(tabbar-display-update))
(add-hook 'after-save-hook 'er/modification-state-change)
;; First-change-hook is called BEFORE the change is made.
(defun er/on-buffer-modification ()
(set-buffer-modified-p t)
(er/modification-state-change))
(add-hook 'first-change-hook 'er/on-buffer-modification)
;; Retrieve original state after revert is made.
(defun er/on-buffer-revert ()
(set-buffer-modified-p nil)
(er/modification-state-change))
(add-hook 'after-revert-hook 'er/on-buffer-revert)
The er/on-buffer-revert function is my attempt to at least reach a reverted buffer state.
Doesn't work either.
The first piece of code, btw, is just to add an additional space tabbar doesn't originaly have.
Any thoughts?

Answer 1

I know you asked this several years ago, but here's a working example that properly supports reverts. Note that it supports tabbar state correctly for the following situations:
buffer reverts
undo back to last saved state
changing the text to match what it was before the last save
(defun my-ignore-buffer-p ()
(not (buffer-file-name)))
(setq my-buffer-hashes (make-hash-table :test 'equal))
(defun my-set-buffer-hash ()
(puthash (current-buffer) (buffer-hash) my-buffer-hashes))
(defun my-get-buffer-hash ()
(gethash (current-buffer) my-buffer-hashes))
(defun my-buffer-hash-changed-p ()
(not (string= (buffer-hash) (my-get-buffer-hash))))
;; Hook save and change events to show modified buffers in tabbar
(defun on-saving-buffer ()
(tabbar-set-template tabbar-current-tabset nil)
(tabbar-display-update))
(defun on-modifying-buffer ()
(unless (my-ignore-buffer-p)
(my-set-buffer-hash)
(set-buffer-modified-p (buffer-modified-p))
(tabbar-set-template tabbar-current-tabset nil)
(tabbar-display-update)))
(defun after-modifying-buffer (begin end length)
(unless (my-ignore-buffer-p)
(set-buffer-modified-p (my-buffer-hash-changed-p))
(tabbar-set-template tabbar-current-tabset nil)
(tabbar-display-update)))
(add-hook 'after-save-hook 'on-saving-buffer)
(add-hook 'first-change-hook 'on-modifying-buffer)
(add-hook 'after-change-functions 'after-modifying-buffer)