Re: Slow fontification in C mode buffers

[Alan Mackenzie <acm@muc.de>]

Hello, Kentaro.

On Fri, Dec 23, 2011 at 10:56:15AM +0900, Kentaro NAKAZAWA wrote:
> Hello. (sorry for my poor english ;)

> Other pattern attached.
> The file is very heavy at edit and undo.


> Geoff Gole <geoffgole@gmail.com> writes:

> > If another data point will help, I've also noticed *very* slow c-mode
> > fontification in a script generated header,
> > /usr/include/GL/gl_mangle.h. In case you don't have this header, a
> > copy is attached.

> > The file is basically several thousand #defines.


> // -*- mode: c++ -*-

> namespace NameSpace1 {
>   namespace NameSpace2 {

>     enum {
>       kFooBarBazType_Attribute0000	= 0x0000,	// Comment0000
>       kFooBarBazType_Attribute0001	= 0x0001,	// Comment0001
>       kFooBarBazType_Attribute0002	= 0x0002,	// Comment0002
>       kFooBarBazType_Attribute0003	= 0x0003,	// Comment0003
>
> [....]
>
>       kFooBarBazType_Attribute0220	= 0x00dc,	// Comment0220
>       kFooBarBazType_Attribute0221	= 0x00dd,	// Comment0221
>       kFooBarBazType_Attribute0222	= 0x00de,	// Comment0222
>     };

>   } // namespace Namespace2
> } // namespace Namespace1

Would you try this patch and let me know how it goes, please.


*** orig/cc-fonts.el	2012-01-06 12:27:14.000000000 +0000
--- cc-fonts.el	2012-01-06 21:48:54.000000000 +0000
***************
*** 1394,1399 ****
--- 1394,1414 ----
  	      (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"
*** orig/cc-langs.el	2012-01-06 12:27:14.000000000 +0000
--- cc-langs.el	2012-01-06 12:54:00.000000000 +0000
***************
*** 2930,2935 ****
--- 2930,2941 ----
  		    ; generics is not yet coded in CC Mode.
  (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



> -- 
> Kentaro Nakazawa

-- 
Alan Mackenzie (Nuremberg, Germany).