[PATCH] emacs: Avoid regexp overflow when tidying citations.

[David Edmondson <dme@dme.org>]

Declare `notmuch-wash-tidy-citations-max', which is the largest region
that `notmuch-wash-tidy-citations' will attempt to improve.
---
 emacs/notmuch-wash.el |   61 ++++++++++++++++++++++++++++---------------------
 1 files changed, 35 insertions(+), 26 deletions(-)

diff --git a/emacs/notmuch-wash.el b/emacs/notmuch-wash.el
index cfcfb21..a7ea5e9 100644
--- a/emacs/notmuch-wash.el
+++ b/emacs/notmuch-wash.el
@@ -187,6 +187,11 @@ is what to put on the button."
 
 ;;
 
+(defcustom notmuch-wash-tidy-citations-max (* 10 1024)
+  "Maximum size of region to tidy."
+  :group 'notmuch
+  :type 'int)
+
 (defun notmuch-wash-tidy-citations (depth)
   "Improve the display of cited regions of a message.
 
@@ -199,32 +204,36 @@ Perform four transformations on the message body:
 - Remove citation trailers standing alone after a block of cited
   text."
 
-  ;; Remove lines of repeated citation leaders with no other content.
-  (goto-char (point-min))
-  (while (re-search-forward "\\(^>[> ]*\n\\)\\{2,\\}" nil t)
-    (replace-match "\\1"))
-
-  ;; Remove citation leaders standing alone before a block of cited
-  ;; text.
-  (goto-char (point-min))
-  (while (re-search-forward "\\(\n\\|^[^>].*\\)\n\\(^>[> ]*\n\\)" nil t)
-    (replace-match "\\1\n"))
-
-  ;; Remove citation trailers standing alone after a block of cited
-  ;; text.
-  (goto-char (point-min))
-  (while (re-search-forward "\\(^>[> ]*\n\\)\\(^$\\|^[^>].*\\)" nil t)
-    (replace-match "\\2"))
-
-  ;; Insert a blank line before a citation if there isn't one.
-  (goto-char (point-min))
-  (while (re-search-forward "\\(^[^>]+\\)\n>" nil t)
-    (replace-match "\\1\n\n>"))
-
-  ;; Insert a blank line after a citation if there isn't one.
-  (goto-char (point-min))
-  (while (re-search-forward "\\(^>.+\\)\n\\([^>]\\)" nil t)
-    (replace-match "\\1\n\n\\2")))
+  ;; If the message is long, don't bother.
+  (unless (> (- (point-max) (point-min))
+	     notmuch-wash-tidy-citations-max)
+
+    ;; Remove lines of repeated citation leaders with no other content.
+    (goto-char (point-min))
+    (while (re-search-forward "\\(^>[> ]*\n\\)\\{2,\\}" nil t)
+      (replace-match "\\1"))
+
+    ;; Remove citation leaders standing alone before a block of cited
+    ;; text.
+    (goto-char (point-min))
+    (while (re-search-forward "\\(\n\\|^[^>].*\\)\n\\(^>[> ]*\n\\)" nil t)
+      (replace-match "\\1\n"))
+
+    ;; Remove citation trailers standing alone after a block of cited
+    ;; text.
+    (goto-char (point-min))
+    (while (re-search-forward "\\(^>[> ]*\n\\)\\(^$\\|^[^>].*\\)" nil t)
+      (replace-match "\\2"))
+
+    ;; Insert a blank line before a citation if there isn't one.
+    (goto-char (point-min))
+    (while (re-search-forward "\\(^[^>]+\\)\n>" nil t)
+      (replace-match "\\1\n\n>"))
+
+    ;; Insert a blank line after a citation if there isn't one.
+    (goto-char (point-min))
+    (while (re-search-forward "\\(^>.+\\)\n\\([^>]\\)" nil t)
+      (replace-match "\\1\n\n\\2"))))
 
 ;;
 
-- 
1.7.2.3