[Emacs-diffs] Changes to emacs/lisp/jit-lock.el,v

[Stefan Monnier]

CVSROOT:        /sources/emacs
Module name:    emacs
Changes by:     Stefan Monnier <monnier>        06/08/01 19:01:24

Index: jit-lock.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/jit-lock.el,v
retrieving revision 1.51
retrieving revision 1.52
diff -u -b -r1.51 -r1.52
--- jit-lock.el 20 Mar 2006 07:52:03 -0000      1.51
+++ jit-lock.el 1 Aug 2006 19:01:24 -0000       1.52
@@ -331,7 +331,7 @@
      ;; from the end of a buffer to its start, can do repeated
      ;; `parse-partial-sexp' starting from `point-min', which can
      ;; take a long time in a large buffer.
-     (let (next)
+     (let ((orig-start start) next)
        (save-match-data
         ;; Fontify chunks beginning at START.  The end of a
         ;; chunk is either `end', or the start of a region
@@ -374,6 +374,21 @@
             (quit (put-text-property start next 'fontified nil)
                   (funcall 'signal (car err) (cdr err))))
 
+           ;; The redisplay engine has already rendered the buffer up-to
+           ;; `orig-start' and won't notice if the above jit-lock-functions
+           ;; changed the appearance of any part of the buffer prior
+           ;; to that.  So if `start' is before `orig-start', we need to
+           ;; cause a new redisplay cycle after this one so that any changes
+           ;; are properly reflected on screen.
+           ;; To make such repeated redisplay happen less often, we can
+           ;; eagerly extend the refontified region with
+           ;; jit-lock-after-change-extend-region-functions.
+           (when (< start orig-start)
+             (run-with-timer
+              0 nil `(lambda ()
+                       (put-text-property ',start ',orig-start
+                                          'fontified t ',(current-buffer)))))
+
           ;; Find the start of the next chunk, if any.
           (setq start (text-property-any next end 'fontified nil))))))))
 
@@ -548,6 +563,19 @@
                '(fontified nil jit-lock-defer-multiline nil)))
              (setq jit-lock-context-unfontify-pos (point-max)))))))))
 
+(defvar jit-lock-start) (defvar jit-lock-end) ; Dynamically scoped variables.
+(defvar jit-lock-after-change-extend-region-functions nil
+  "Hook that can extend the text to refontify after a change.
+This is run after every buffer change.  The functions are called with
+the three arguments of `after-change-functions': START END OLD-LEN.
+The extended region to refontify is returned indirectly by modifying
+the variables `jit-lock-start' and `jit-lock-end'.
+
+Note that extending the region this way is not strictly necessary,
+except that the nature of the redisplay code tends to otherwise leave
+some of the rehighlighted text displayed with the old highlight until the
+next redisplay.  See comment in `jit-lock-fontify-now'.")
+
 (defun jit-lock-after-change (start end old-len)
   "Mark the rest of the buffer as not fontified after a change.
 Installed on `after-change-functions'.
@@ -557,35 +585,15 @@
 in case the syntax of those lines has changed.  Refontification
 will take place when text is fontified stealthily."
   (when (and jit-lock-mode (not memory-full))
-    (let ((region (font-lock-extend-region start end old-len)))
-      (save-excursion
+    (let ((jit-lock-start start)
+          (jit-lock-end end))
        (with-buffer-prepared-for-jit-lock
-        ;; It's important that the `fontified' property be set from the
-        ;; beginning of the line, else font-lock will properly change the
-        ;; text's face, but the display will have been done already and will
-        ;; be inconsistent with the buffer's content.
-        ;; 
-        ;; FIXME!!! (Alan Mackenzie, 2006-03-14): If start isn't at a BOL,
-        ;; expanding the region to BOL might mis-fontify, should the BOL not
-        ;; be at a "safe" position.
-        (setq start (if region
-                        (car region)
-                      (goto-char start)
-                      (line-beginning-position)))
-
-        ;; If we're in text that matches a multi-line font-lock pattern,
-        ;; make sure the whole text will be redisplayed.
-        ;; I'm not sure this is ever necessary and/or sufficient.  -stef
-        (when (get-text-property start 'font-lock-multiline)
-          (setq start (or (previous-single-property-change
-                           start 'font-lock-multiline)
-                          (point-min))))
-
-        (if region (setq end (cdr region)))
+          (run-hook-with-args 'jit-lock-after-change-extend-region-functions
+                              start end old-len)
         ;; Make sure we change at least one char (in case of deletions).
-        (setq end (min (max end (1+ start)) (point-max)))
+          (setq jit-lock-end (min (max jit-lock-end (1+ start)) (point-max)))
         ;; Request refontification.
-        (put-text-property start end 'fontified nil))
+          (put-text-property jit-lock-start jit-lock-end 'fontified nil))
        ;; Mark the change for deferred contextual refontification.
        (when jit-lock-context-unfontify-pos
          (setq jit-lock-context-unfontify-pos
@@ -594,7 +602,7 @@
                ;; usually it will be refontified by virtue of being
                ;; displayed, but if it's outside of any displayed area in the
                ;; buffer, only jit-lock-context-* will re-fontify it.
-               (min jit-lock-context-unfontify-pos start)))))))
+              (min jit-lock-context-unfontify-pos jit-lock-start))))))
 
 (provide 'jit-lock)