From 7a20ebe5ca884954e34c5129f70c211fef266369 Mon Sep 17 00:00:00 2001
From: Alan Mackenzie <acm@muc.de>
Date: Thu, 23 Jun 2016 16:12:45 +0000
Subject: [PATCH] Make typing into incomplete C++ raw strings work, and make it
 work fast enough

* lisp/progmodes/cc-engine.el (c-beginning-of-macro, c-state-pp-to-literal):
Put `save-match-data' around calls to `looking-at' to enable the use of the
match data in higher level functions.

* lisp/progmodes/cc-fonts.el (c-font-lock-declarations)
(c-font-lock-cut-off-declarators): Use `limit' rather than `(point-max)' as a
limit to speed up handling of C++ raw strings.
---
 lisp/progmodes/cc-engine.el | 55 +++++++++++++++++++++++----------------------
 lisp/progmodes/cc-fonts.el  |  4 ++--
 2 files changed, 30 insertions(+), 29 deletions(-)

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 595d57756eb..5fa04034585 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -305,7 +305,7 @@ comment at the start of cc-engine.el for more info."
 	    (forward-line -1))
 	  (back-to-indentation)
 	  (if (and (<= (point) here)
-		   (looking-at c-opt-cpp-start)
+		   (save-match-data (looking-at c-opt-cpp-start))
 		   (c-macro-is-genuine-p))
 	      (progn
 		(setq c-macro-cache (cons (point) nil)
@@ -2304,32 +2304,33 @@ comment at the start of cc-engine.el for more info."
   ;; 7 (comment type) and 8 (start of comment/string) (and possibly 9) of
   ;; STATE are valid.
   (save-excursion
-    (let ((s (parse-partial-sexp from to))
-	  ty co-st)
-      (cond
-       ((or (nth 3 s) (nth 4 s))	; in a string or comment
-	(setq ty (cond
-		  ((nth 3 s) 'string)
-		  ((nth 7 s) 'c++)
-		  (t 'c)))
-	(parse-partial-sexp (point) (point-max)
-			    nil		   ; TARGETDEPTH
-			    nil		   ; STOPBEFORE
-			    s		   ; OLDSTATE
-			    'syntax-table) ; stop at end of literal
-	`(,s ,ty (,(nth 8 s) . ,(point))))
-
-       ((and (not not-in-delimiter)	; inside a comment starter
-	     (not (bobp))
-	     (progn (backward-char)
-		    (and (not (looking-at "\\s!"))
-			 (looking-at c-comment-start-regexp))))
-	(setq ty (if (looking-at c-block-comment-start-regexp) 'c 'c++)
-	      co-st (point))
-	(forward-comment 1)
-	`(,s ,ty (,co-st . ,(point))))
-
-       (t `(,s))))))
+    (save-match-data
+      (let ((s (parse-partial-sexp from to))
+	    ty co-st)
+	(cond
+	 ((or (nth 3 s) (nth 4 s))	; in a string or comment
+	  (setq ty (cond
+		    ((nth 3 s) 'string)
+		    ((nth 7 s) 'c++)
+		    (t 'c)))
+	  (parse-partial-sexp (point) (point-max)
+			      nil	   ; TARGETDEPTH
+			      nil	   ; STOPBEFORE
+			      s		   ; OLDSTATE
+			      'syntax-table) ; stop at end of literal
+	  `(,s ,ty (,(nth 8 s) . ,(point))))
+
+	 ((and (not not-in-delimiter)	; inside a comment starter
+	       (not (bobp))
+	       (progn (backward-char)
+		      (and (not (looking-at "\\s!"))
+			   (looking-at c-comment-start-regexp))))
+	  (setq ty (if (looking-at c-block-comment-start-regexp) 'c 'c++)
+		co-st (point))
+	  (forward-comment 1)
+	  `(,s ,ty (,co-st . ,(point))))
+
+	 (t `(,s)))))))
 
 (defun c-state-safe-place (here)
   ;; Return a buffer position before HERE which is "safe", i.e. outside any
diff --git a/lisp/progmodes/cc-fonts.el b/lisp/progmodes/cc-fonts.el
index 65ec5c3f044..3a8c9ec0ec4 100644
--- a/lisp/progmodes/cc-fonts.el
+++ b/lisp/progmodes/cc-fonts.el
@@ -1396,7 +1396,7 @@ casts and declarations are fontified.  Used on level 2 and higher."
 					     'c-decl-id-start)))))
 
 		(c-font-lock-declarators
-		 (point-max) decl-list (cadr decl-or-cast)))
+		 (min limit (point-max)) decl-list (cadr decl-or-cast)))
 
 	      ;; A declaration has been successfully identified, so do all the
 	      ;; fontification of types and refs that've been recorded.
@@ -1542,7 +1542,7 @@ casts and declarations are fontified.  Used on level 2 and higher."
 		(c-forward-syntactic-ws))
 	      ;; At a real declaration?
 	      (if (memq (c-forward-type t) '(t known found decltype))
-		  (c-font-lock-declarators (point-max) t is-typedef)))
+		  (c-font-lock-declarators limit t is-typedef)))
 	  nil)))))
 
 (defun c-font-lock-enclosing-decls (limit)
-- 
2.11.4.GIT