From: Tino Calancha <tino.calancha@gmail.com>
To: Drew Adams <drew.adams@oracle.com>
Cc: 25243@debbugs.gnu.org, Tino Calancha <tino.calancha@gmail.com>
Subject: bug#25243: 26.0.50; ffap-guesser very slow w/ region active in large diff files
Date: Sat, 24 Dec 2016 11:53:27 +0900 [thread overview]
Message-ID: <87k2aqdom0.fsf@gmail.com> (raw)
In-Reply-To: <e264852a-17db-450c-947e-4499a69b8c92@default> (Drew Adams's message of "Fri, 23 Dec 2016 07:41:02 -0800 (PST)")
Drew Adams <drew.adams@oracle.com> writes:
> below
>
>> > 2. Instead of testing whether the max-length var is nil, I'd suggest
>> > testing it with `natnump', to take care of the unexpected case where
>> > it might get assigned a non-number.
>> Yes, `natnump' is a better choice.
>
>> + (if (or (not (natnump ffap-max-region-length))
>> + (< region-len ffap-max-region-length)) ; Bug#25243.
>> + (setf ffap-string-at-point-region (list beg end)
>> + ffap-string-at-point
>> + (buffer-substring-no-properties beg end))
>> + (setf ffap-string-at-point-region (list 1 1)
>> + ffap-string-at-point ""))))
>
> I'd suggest the other way around. What you have lets someone or
> some code assign a non-number and get the same slow behavior we
> want to avoid. I'd say (and (natnump ...) (< region-len ...)).
>
> IOW, if it's not a natnump and the size is not smaller than that
> number then don't use the region.
It sounds reasonable. Thank you.
If i don't see further comments in a few days i will push
the following patch to the master branch:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
From 7e8268b975c8385015769755e8ba1e9854d64da1 Mon Sep 17 00:00:00 2001
From: Tino Calancha <tino.calancha@gmail.com>
Date: Sat, 24 Dec 2016 11:31:53 +0900
Subject: [PATCH] ffap-string-at-point: Limit max length of active region
Do not spend time checking large strings which are
likely not valid candidates (Bug#25243).
* lisp/ffap.el (ffap-max-region-length): New variable.
(ffap-string-at-point): Use it.
* test/lisp/ffap-tests.el: New test suite.
(ffap-tests-25243): Add test for this bug.
---
lisp/ffap.el | 25 ++++++++++++++++-------
test/lisp/ffap-tests.el | 54 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+), 7 deletions(-)
create mode 100644 test/lisp/ffap-tests.el
diff --git a/lisp/ffap.el b/lisp/ffap.el
index 3d7cebadcf..99bb65faaf 100644
--- a/lisp/ffap.el
+++ b/lisp/ffap.el
@@ -203,6 +203,11 @@ ffap-foo-at-bar-prefix
)
:group 'ffap)
+(defvar ffap-max-region-length 1024
+ "Maximum active region length.
+When the region is active and larger than this value,
+`ffap-string-at-point' returns an empty string.")
+
\f
;;; Peanut Gallery (More User Variables):
;;
@@ -1101,8 +1106,10 @@ ffap-string-at-point
string syntax parameters in `ffap-string-at-point-mode-alist'.
If MODE is not found, we use `file' instead of MODE.
If the region is active, return a string from the region.
-Sets the variable `ffap-string-at-point' and the variable
-`ffap-string-at-point-region'."
+Set the variable `ffap-string-at-point' and the variable
+`ffap-string-at-point-region'.
+When the region is active and larger than `ffap-max-region-length',
+return an empty string, and set `ffap-string-at-point-region' to '(1 1)."
(let* ((args
(cdr
(or (assq (or mode major-mode) ffap-string-at-point-mode-alist)
@@ -1119,11 +1126,15 @@ ffap-string-at-point
(save-excursion
(skip-chars-forward (car args))
(skip-chars-backward (nth 2 args) pt)
- (point)))))
- (setq ffap-string-at-point
- (buffer-substring-no-properties
- (setcar ffap-string-at-point-region beg)
- (setcar (cdr ffap-string-at-point-region) end)))))
+ (point))))
+ (region-len (- (max beg end) (min beg end))))
+ (if (and (natnump ffap-max-region-length)
+ (< region-len ffap-max-region-length)) ; Bug#25243.
+ (setf ffap-string-at-point-region (list beg end)
+ ffap-string-at-point
+ (buffer-substring-no-properties beg end))
+ (setf ffap-string-at-point-region (list 1 1)
+ ffap-string-at-point ""))))
(defun ffap-string-around ()
;; Sometimes useful to decide how to treat a string.
diff --git a/test/lisp/ffap-tests.el b/test/lisp/ffap-tests.el
new file mode 100644
index 0000000000..61fa891fe7
--- /dev/null
+++ b/test/lisp/ffap-tests.el
@@ -0,0 +1,54 @@
+;;; ffap-tests.el --- Test suite for ffap.el -*- lexical-binding: t -*-
+
+;; Copyright (C) 2016 Free Software Foundation, Inc.
+
+;; Author: Tino Calancha <tino.calancha@gmail.com>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'ert)
+(require 'ffap)
+
+(ert-deftest ffap-tests-25243 ()
+ "Test for http://debbugs.gnu.org/25243 ."
+ (let ((file (make-temp-file "test-Bug#25243")))
+ (unwind-protect
+ (with-temp-file file
+ (let ((str "diff --git b/lisp/ffap.el a/lisp/ffap.el
+index 3d7cebadcf..ad4b70d737 100644
+--- b/lisp/ffap.el
++++ a/lisp/ffap.el
+@@ -203,6 +203,9 @@ ffap-foo-at-bar-prefix
+"))
+ (transient-mark-mode 1)
+ (when (natnump ffap-max-region-length)
+ (insert
+ (concat
+ str
+ (make-string ffap-max-region-length #xa)
+ (format "%s ENDS HERE" file)))
+ (mark-whole-buffer)
+ (should (equal "" (ffap-string-at-point)))
+ (should (equal '(1 1) ffap-string-at-point-region)))))
+ (and (file-exists-p file) (delete-file file)))))
+
+(provide 'ffap-tests)
+
+;;; ffap-tests.el ends here
--
2.11.0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
In GNU Emacs 26.0.50.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.5)
of 2016-12-23
Repository revision: eff901b8a39f42ddedf4c1db833b9071cae5962f
next prev parent reply other threads:[~2016-12-24 2:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-21 15:35 bug#25243: 26.0.50; ffap-guesser very slow w/ region active in large diff files Tino Calancha
2016-12-21 16:22 ` Drew Adams
2016-12-22 4:31 ` Tino Calancha
2016-12-22 17:22 ` Drew Adams
2016-12-23 7:12 ` Tino Calancha
2016-12-23 15:41 ` Drew Adams
2016-12-24 2:53 ` Tino Calancha [this message]
2016-12-30 6:41 ` Tino Calancha
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