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Re: What happens with overlays when their buffer is killed?
From: |
Marcin Borkowski |
Subject: |
Re: What happens with overlays when their buffer is killed? |
Date: |
Mon, 26 Mar 2018 18:44:04 +0200 |
User-agent: |
mu4e 1.1.0; emacs 27.0.50 |
On 2018-03-26, at 17:05, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Marcin Borkowski <mbork@mbork.pl>
>> Date: Mon, 26 Mar 2018 09:25:27 +0200
>>
>> assume that I create a few overlays in some buffer, and then I kill that
>> buffer. What happens with the overlays? If they were not assigned to
>> a variable, do they get garbage collected?
>
> They will be GC'ed on the next opportunity when Emacs decides to GC.
Thanks, that's great!
Here is my code displaying the size of the attachment in message-mode
and highlighting the "important" parts of the mml tag. (I will probably
write about it on my blog some day.)
--8<---------------cut here---------------start------------->8---
(require 'cl)
(defconst iec-prefixes ["" "Ki" "Mi" "Gi"])
(defun human-readable-size (size)
"Return SIZE as human-readable string, using IEC prefixes."
(let* ((order (1- (max 1 (ceiling (log (max size 1) 1024)))))
(prefix (elt iec-prefixes (min order (length iec-prefixes))))
(size-in-unit (/ size (expt 1024.0 order)))
(precision (max 3 (+ 2 (floor (log (max size-in-unit 1) 10)))))
(size-str (format (format "%%.%dg%%sB" precision) size-in-unit
prefix)))
size-str))
(defun mml-add-size-to-message-part (name &rest plist)
"Add filesize to the inserted part if applicable"
(if (and (eq name 'part)
(plist-member plist 'filename))
(plist-put plist 'size
(number-to-string
(file-attribute-size
(file-attributes
(plist-get plist filename))))))
(cons name plist))
(advice-add 'mml-insert-empty-tag
:filter-args
'mml-add-size-to-message-part)
(defun embolden-with-overlay (start end)
"Embolden the text between START and END, using an overlay."
(let ((tmp-overlay (make-overlay start end)))
(overlay-put tmp-overlay 'face 'bold)))
(defun make-mml-tag-before-point-more-legible (name &rest plist)
"Apply boldface to relevant parts of mml tag before point."
(save-excursion
(let ((opoint (point)))
(when (search-backward (format "<#%s" name) nil nil)
(goto-char (match-end 0))
(while (looking-at " [a-z]+=")
(goto-char (match-end 0))
(if (eq (char-after) ?\")
(embolden-with-overlay
(progn
(forward-char)
(point))
(progn (while (and (search-forward "\"" opoint t)
(save-excursion
(backward-char)
(cl-oddp (skip-chars-backward "\\\\")))))
(point)))
(embolden-with-overlay
(point)
(progn
(re-search-forward "[ >]" opoint t)
(backward-char)
(point)))))))))
(advice-add 'mml-insert-tag :after 'make-mml-tag-before-point-more-legible)
--8<---------------cut here---------------end--------------->8---
Comments welcome.
--
Marcin Borkowski
http://mbork.pl