Function: text-clone--maintain

text-clone--maintain is a byte-compiled function defined in subr.el.gz.

Signature

(text-clone--maintain OL1 AFTER BEG END &optional LEN)

Documentation

Propagate the changes made under the overlay OL1 to the other clones.

This is used on the modification-hooks property of text clones.

Source Code

;; Defined in /usr/src/emacs/lisp/subr.el.gz
(defun text-clone--maintain (ol1 after beg end &optional _len)
  "Propagate the changes made under the overlay OL1 to the other clones.
This is used on the `modification-hooks' property of text clones."
  (when (and after (not undo-in-progress)
             (not text-clone--maintaining)
             (overlay-start ol1))
    (let ((margin (if (overlay-get ol1 'text-clone-spreadp) 1 0)))
      (setq beg (max beg (+ (overlay-start ol1) margin)))
      (setq end (min end (- (overlay-end ol1) margin)))
      (when (<= beg end)
	(save-excursion
	  (when (overlay-get ol1 'text-clone-syntax)
	    ;; Check content of the clone's text.
	    (let ((cbeg (+ (overlay-start ol1) margin))
		  (cend (- (overlay-end ol1) margin)))
	      (goto-char cbeg)
	      (save-match-data
		(if (not (re-search-forward
			  (overlay-get ol1 'text-clone-syntax) cend t))
		    ;; Mark the overlay for deletion.
		    (setq end cbeg)
		  (when (< (match-end 0) cend)
		    ;; Shrink the clone at its end.
		    (setq end (min end (match-end 0)))
		    (move-overlay ol1 (overlay-start ol1)
				  (+ (match-end 0) margin)))
		  (when (> (match-beginning 0) cbeg)
		    ;; Shrink the clone at its beginning.
		    (setq beg (max (match-beginning 0) beg))
		    (move-overlay ol1 (- (match-beginning 0) margin)
				  (overlay-end ol1)))))))
	  ;; Now go ahead and update the clones.
	  (let ((head (- beg (overlay-start ol1)))
		(tail (- (overlay-end ol1) end))
		(str (buffer-substring beg end))
		(nothing-left t)
		(text-clone--maintaining t))
	    (dolist (ol2 (overlay-get ol1 'text-clones))
	      (let ((oe (overlay-end ol2)))
		(unless (or (eq ol1 ol2) (null oe))
		  (setq nothing-left nil)
		  (let ((mod-beg (+ (overlay-start ol2) head)))
		    ;;(overlay-put ol2 'modification-hooks nil)
		    (goto-char (- (overlay-end ol2) tail))
		    (unless (> mod-beg (point))
		      (save-excursion (insert str))
		      (delete-region mod-beg (point)))
		    ;;(overlay-put ol2 'modification-hooks '(text-clone--maintain))
		    ))))
	    (if nothing-left (delete-overlay ol1))))))))