From 9d5a8f0b3c3fe959d307d5b2f106943aa970c59b Mon Sep 17 00:00:00 2001
From: Alan Mackenzie <acm@muc.de>
Date: Sun, 8 Jan 2012 12:49:44 +0000
Subject: [PATCH] Optimise font locking in long enum definitions.

---
 lisp/ChangeLog             |  9 +++++++++
 lisp/progmodes/cc-fonts.el | 15 +++++++++++++++
 lisp/progmodes/cc-langs.el |  6 ++++++
 lisp/progmodes/cc-mode.el  |  2 +-
 4 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 9e490a1e367..ab8572b7f93 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,12 @@
+2012-01-08  Alan Mackenzie  <acm@muc.de>
+
+	Optimise font locking in long enum definitions.
+
+	* progmodes/cc-fonts.el (c-font-lock-declarations): Add an extra
+	arm to a cond form to handle enums.
+	* progmodes/cc-langs.el (c-enums-contain-decls): New lang variable.
+	* progmodes/cc-mode.el (c-font-lock-fontify-region): Correct a typo.
+
 2012-01-07  Paul Eggert  <eggert@cs.ucla.edu>
 
 	* files.el (move-file-to-trash): Preserve default file modes on error.
diff --git a/lisp/progmodes/cc-fonts.el b/lisp/progmodes/cc-fonts.el
index ee5fb1bd086..f52864df809 100644
--- a/lisp/progmodes/cc-fonts.el
+++ b/lisp/progmodes/cc-fonts.el
@@ -1428,6 +1428,21 @@ casts and declarations are fontified.  Used on level 2 and higher."
 	      (c-fontify-recorded-types-and-refs)
 	      nil)
 
+	     ((and (not c-enums-contain-decls)
+		   ;; An optimisation quickly to eliminate scans of long enum
+		   ;; declarations in the next cond arm.
+		   (let ((paren-state (c-parse-state)))
+		     (and
+		      (numberp (car paren-state))
+		      (save-excursion
+			(goto-char (car paren-state))
+			(c-backward-token-2)
+			(or (looking-at c-brace-list-key)
+			    (progn
+			      (c-backward-token-2)
+			      (looking-at c-brace-list-key)))))))
+	      t)
+
 	     (t
 	      ;; Are we at a declarator?  Try to go back to the declaration
 	      ;; to check this.  If we get there, check whether a "typedef"
diff --git a/lisp/progmodes/cc-langs.el b/lisp/progmodes/cc-langs.el
index b565cf98b3c..fafbfb70552 100644
--- a/lisp/progmodes/cc-langs.el
+++ b/lisp/progmodes/cc-langs.el
@@ -2938,6 +2938,12 @@ expression is considered to be a type."
 	(consp (c-lang-const c-<>-arglist-kwds))))
 (c-lang-defvar c-recognize-<>-arglists (c-lang-const c-recognize-<>-arglists))
 
+(c-lang-defconst c-enums-contain-decls
+  "Non-nil means that an enum structure can contain declarations."
+  t nil
+  java t)
+(c-lang-defvar c-enums-contain-decls (c-lang-const c-enums-contain-decls))
+
 (c-lang-defconst c-recognize-paren-inits
   "Non-nil means that parenthesis style initializers exist,
 i.e. constructs like
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index 600d4fc8b56..b74d878516d 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -1158,7 +1158,7 @@ Note that the style variables are always made local to the buffer."
   ;; Effectively advice around `font-lock-fontify-region' which extends the
   ;; region (BEG END), for example, to avoid context fontification chopping
   ;; off the start of the context.  Do not do anything if it's already been
-  ;; done (i.e. from and after-change fontification.  An example (C++) where
+  ;; done (i.e. from an after-change fontification.  An example (C++) where
   ;; this used to happen is this:
   ;;
   ;;     template <typename T>
-- 
2.11.4.GIT