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

[Alan Mackenzie]

Index: emacs/lisp/jit-lock.el
diff -u emacs/lisp/jit-lock.el:1.48 emacs/lisp/jit-lock.el:1.49
--- emacs/lisp/jit-lock.el:1.48 Mon Feb  6 14:33:34 2006
+++ emacs/lisp/jit-lock.el      Tue Mar 14 18:23:47 2006
@@ -557,36 +557,44 @@
 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))
-    (save-excursion
-      (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.
-       (goto-char start)
-       (setq start (line-beginning-position))
+    (let ((region (font-lock-extend-region start end old-len)))
+      (save-excursion
+       (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 (- 1 font-lock-lines-before))))
 
-       ;; 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 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))))
 
-       ;; Make sure we change at least one char (in case of deletions).
-       (setq end (min (max end (1+ start)) (point-max)))
-       ;; Request refontification.
-       (put-text-property start end 'fontified nil))
-      ;; Mark the change for deferred contextual refontification.
-      (when jit-lock-context-unfontify-pos
-       (setq jit-lock-context-unfontify-pos
-              ;; Here we use `start' because nothing guarantees that the
-              ;; text between start and end will be otherwise refontified:
-              ;; 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))))))
+        (if region (setq end (cdr region)))
+        ;; Make sure we change at least one char (in case of deletions).
+        (setq end (min (max end (1+ start)) (point-max)))
+        ;; Request refontification.
+        (put-text-property start end 'fontified nil))
+       ;; Mark the change for deferred contextual refontification.
+       (when jit-lock-context-unfontify-pos
+         (setq jit-lock-context-unfontify-pos
+               ;; Here we use `start' because nothing guarantees that the
+               ;; text between start and end will be otherwise refontified:
+               ;; 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)))))))
 
 (provide 'jit-lock)