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(undo-ask-before-discard): New var.

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(undo-outer-limit-truncate): Implement it.
(undo-extra-outer-limit): Doc update.
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Luc Teirlinck 2005-01-30 00:32:39 +00:00
parent 49b8b5dcb3
commit 28cb725d59
1 changed files with 63 additions and 20 deletions
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83
lisp/simple.el
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@ -1525,33 +1525,76 @@ is not *inside* the region START...END."
'(0 . 0)))
'(0 . 0)))
(defcustom undo-ask-before-discard t
"If non-nil ask about discarding undo info for the current command.
Normally, Emacs discards the undo info for the current command if
it exceeds `undo-outer-limit'. But if you set this option
non-nil, it asks in the echo area whether to discard the info.
If you answer no, there a slight risk that Emacs might crash, so
only do it if you really want to undo the command.
This option is mainly intended for debugging. You have to be
careful if you use it for other purposes. Garbage collection is
inhibited while the question is asked, meaning that Emacs might
leak memory. So you should make sure that you do not wait
excessively long before answering the question."
:type 'boolean
:group 'undo
:version "21.4")
(defvar undo-extra-outer-limit nil
"If non-nil, an extra level of size that's ok in an undo item.
We don't ask the user about truncating the undo list until the
current item gets bigger than this amount.")
current item gets bigger than this amount.
This variable only matters if `undo-ask-before-discard' is non-nil.")
(make-variable-buffer-local 'undo-extra-outer-limit)
;; When the first undo batch in an undo list is longer than undo-outer-limit,
;; this function gets called to ask the user what to do.
;; Garbage collection is inhibited around the call,
;; so it had better not do a lot of consing.
;; When the first undo batch in an undo list is longer than
;; undo-outer-limit, this function gets called to warn the user that
;; the undo info for the current command was discarded. Garbage
;; collection is inhibited around the call, so it had better not do a
;; lot of consing.
(setq undo-outer-limit-function 'undo-outer-limit-truncate)
(defun undo-outer-limit-truncate (size)
(when (or (null undo-extra-outer-limit)
(> size undo-extra-outer-limit))
;; Don't ask the question again unless it gets even bigger.
;; This applies, in particular, if the user quits from the question.
;; Such a quit quits out of GC, but something else will call GC
;; again momentarily. It will call this function again,
;; but we don't want to ask the question again.
(setq undo-extra-outer-limit (+ size 50000))
(if (let (use-dialog-box)
(yes-or-no-p (format "Buffer %s undo info is %d bytes long; discard it? "
(buffer-name) size)))
(progn (setq buffer-undo-list nil)
(setq undo-extra-outer-limit nil)
t)
nil)))
(if undo-ask-before-discard
(when (or (null undo-extra-outer-limit)
(> size undo-extra-outer-limit))
;; Don't ask the question again unless it gets even bigger.
;; This applies, in particular, if the user quits from the question.
;; Such a quit quits out of GC, but something else will call GC
;; again momentarily. It will call this function again,
;; but we don't want to ask the question again.
(setq undo-extra-outer-limit (+ size 50000))
(if (let (use-dialog-box track-mouse executing-kbd-macro )
(yes-or-no-p (format "Buffer %s undo info is %d bytes long; discard it? "
(buffer-name) size)))
(progn (setq buffer-undo-list nil)
(setq undo-extra-outer-limit nil)
t)
nil))
(display-warning '(undo discard-info)
(concat
(format "Buffer %s undo info was %d bytes long.\n"
(buffer-name) size)
"The undo info was discarded because it exceeded \
`undo-outer-limit'.
This is normal if you executed a command that made a huge change
to the buffer. In that case, to prevent similar problems in the
future, set `undo-outer-limit' to a value that is large enough to
cover the maximum size of normal changes you expect a single
command to make, but not so large that it might exceed the
maximum memory allotted to Emacs.
If you did not execute any such command, the situation is
probably due to a bug and you should report it.
You can disable the popping up of this buffer by adding the entry
\(undo discard-info) to the user option `warning-suppress-types'.\n")
:warning)
(setq buffer-undo-list nil)
t))
(defvar shell-command-history nil
"History list for some commands that read shell commands.")