From 19f7908595ac9c2f7510a966dbd52940b086efe5 Mon Sep 17 00:00:00 2001
From: Simon Marshall <simon@gnu.org>
Date: Thu, 1 Jun 1995 09:26:48 +0000
Subject: [PATCH] New version 3.06 from author.

---
 lisp/fast-lock.el | 630 ++++++++++++++++++++++++++--------------------
 1 file changed, 361 insertions(+), 269 deletions(-)

diff --git a/lisp/fast-lock.el b/lisp/fast-lock.el
index 285c95ae979..c6c268bbfb5 100644
--- a/lisp/fast-lock.el
+++ b/lisp/fast-lock.el
@@ -1,10 +1,10 @@
-;;; fast-lock.el --- Automagic text properties saving for fast font-lock-mode.
+;;; fast-lock.el --- Automagic text properties caching for fast Font Lock mode.
 
-;; Copyright (C) 1994 Free Software Foundation, Inc.
+;; Copyright (C) 1994, 1995 Free Software Foundation, Inc.
 
-;; Author: Simon Marshall <Simon.Marshall@mail.esrin.esa.it>
+;; Author: Simon Marshall <simon@gnu.ai.mit.edu>
 ;; Keywords: faces files
-;; Version: 3.05
+;; Version: 3.06
 
 ;;; This file is part of GNU Emacs.
 
@@ -27,23 +27,14 @@
 ;; Purpose:
 ;;
 ;; To make visiting a file in `font-lock-mode' faster by restoring its face
-;; text properties from automatically saved associated font lock cache files.
+;; text properties from automatically saved associated Font Lock cache files.
 ;;
-;; See also the face-lock package.
+;; See caveats and feedback below.
 ;; See also the lazy-lock package.  (But don't use the two at the same time!)
 
-;; Note that:
-;;
-;; - A cache will be saved when visiting a compressed file using crypt++, but
-;;   not be read.  This is a "feature"/"consequence"/"bug" of crypt++.
-
 ;; Installation:
 ;; 
-;; Put this file somewhere where Emacs can find it (i.e., in one of the paths
-;; in your `load-path'), `byte-compile-file' it, and put in your ~/.emacs:
-;;
-;; (autoload 'turn-on-fast-lock "fast-lock"
-;;   "Unconditionally turn on Fast Lock mode.")
+;; Put in your ~/.emacs:
 ;;
 ;; (add-hook 'font-lock-mode-hook 'turn-on-fast-lock)
 ;;
@@ -51,31 +42,23 @@
 ;; so-called "gaudier" fontification regexps on big files without frustration).
 ;;
 ;; When you visit a file (which has `font-lock-mode' enabled) that has a
-;; corresponding font lock cache file associated with it, the font lock cache
-;; will be loaded from that file instead of being generated by font-lock code.
+;; corresponding Font Lock cache file associated with it, the Font Lock cache
+;; will be loaded from that file instead of being generated by Font Lock code.
+
+;; Caveats:
 ;;
-;; Font lock caches will be saved:
-;;  - For all buffers with Fast Lock mode enabled when you exit from Emacs.
-;;  - For a buffer with Fast Lock mode enabled when you kill the buffer.
-;; To provide control over how such cache files are written automagically, see
-;; variable `fast-lock-cache-directories'.  To provide control over which such
-;; cache files are written, see variables `fast-lock-save-others' and
-;; `fast-lock-save-size'.  Only cache files which were generated using the same
-;; `font-lock-keywords' as you are using will be used.
+;; A cache will be saved when visiting a compressed file using crypt++, but not
+;; be read.  This is a "feature"/"consequence"/"bug" of crypt++.
 ;;
-;; As an illustration of the time saving, a 115k file of Emacs C code took 95
-;; seconds to fontify using Emacs 19.25 on a Sun SparcStation 2 LX (using
-;; `c-font-lock-keywords-2').  The font lock cache file takes around 2 seconds
-;; to load (with around 4 seconds to generate and save).  Bite it.  Believe it.
-;; (For Lucid Emacs 19.10, the figures on a similar machine, file, and regexps,
-;; are 70, around 4, and around 4, seconds, respectively; for Emacs 19.28 the
-;; fontification takes around 26 seconds.)
+;; Version control packages are likely to stamp all over file modification
+;; times.  Therefore the act of checking out may invalidate a cache.
 
 ;; Feedback:
 ;;
-;; Please send me bug reports, bug fixes, and extensions, so that I can
-;; merge them into the master source.
-;;     - Simon Marshall (Simon.Marshall@mail.esrin.esa.it)
+;; Feedback is welcome.
+;; To submit a bug report (or make comments) please use the mechanism provided:
+;;
+;; M-x fast-lock-submit-bug-report RET
 
 (require 'font-lock)
 
@@ -83,16 +66,37 @@
   ;; Shut Emacs' byte-compiler up (cf. stop me getting mail from users).
   (setq byte-compile-warnings '(free-vars callargs redefine)))
 
-;; User variables:
+(defun fast-lock-submit-bug-report ()
+  "Submit via mail a bug report on fast-lock.el."
+  (interactive)
+  (let ((reporter-prompt-for-summary-p t))
+    (reporter-submit-bug-report "simon@gnu.ai.mit.edu" "fast-lock 3.06"
+     '(fast-lock-cache-directories fast-lock-minimum-size
+       fast-lock-save-others fast-lock-save-events fast-lock-save-faces)
+     nil nil
+     (concat "Hi Si.,
+
+I want to report a bug.  I've read the `Bugs' section of `Info' on Emacs, so I
+know how to make a clear and unambiguous report.  To reproduce the bug:
+
+Start a fresh Emacs via `" invocation-name " -no-init-file -no-site-file'.
+In the `*scratch*' buffer, evaluate:"))))
+
+;;;###autoload
+(defvar fast-lock-mode nil)		; for modeline
+(defvar fast-lock-cache-timestamp nil)	; for saving/reading
+(defvar fast-lock-cache-filename nil)	; for deleting
+
+;; User Variables:
 
 (defvar fast-lock-cache-directories '("." "~/.emacs-flc")
-; - `internal', keep each file's font lock cache file in the same file.
-; - `external', keep each file's font lock cache file in the same directory.
-  "Directories in which font lock cache files are saved and read.
+; - `internal', keep each file's Font Lock cache file in the same file.
+; - `external', keep each file's Font Lock cache file in the same directory.
+  "Directories in which Font Lock cache files are saved and read.
 Each item should be either DIR or a cons pair of the form (REGEXP . DIR) where
 DIR is a directory name (relative or absolute) and REGEXP is a regexp.
 
-An attempt will be made to save or read font lock cache files using these items
+An attempt will be made to save or read Font Lock cache files using these items
 until one succeeds (i.e., until a readable or writable one is found).  If an
 item contains REGEXP, DIR is used only if the buffer file name matches REGEXP.
 For example:
@@ -101,174 +105,219 @@ For example:
        \"~/.emacs-flc\")
 
 would cause a file's current directory to be used if the file is under your
-home directory hierarchy, and the absolute directory otherwise.")
+home directory hierarchy, or otherwise the absolute directory `~/.emacs-flc'.")
 
-(defvar fast-lock-save-size (* 10 1024)
-  "If non-nil, the minimum size for buffer files.
-Only buffer files at least this size can have associated font lock cache files
-saved.  If nil, means size is irrelevant.")
+(defvar fast-lock-minimum-size (* 25 1024)
+  "If non-nil, the minimum size for buffers.
+Only buffers more than this can have associated Font Lock cache files saved.
+If nil, means size is irrelevant.")
 
-(defvar fast-lock-save-others t
-  "If non-nil, save font lock cache files irrespective of file owner.
-If nil, means only buffer files owned by you have a font lock cache saved.")
+(defvar fast-lock-save-events '(kill-buffer kill-emacs)
+  "A list of events under which caches will be saved.
+Valid events are `save-buffer', `kill-buffer' and `kill-emacs'.
+If concurrent editing sessions use the same associated cache file for a file's
+buffer, then you should add `save-buffer' to this list.")
 
-(defvar fast-lock-mode nil)		; for modeline
-(defvar fast-lock-cache-timestamp nil)	; for saving/reading
-(make-variable-buffer-local 'fast-lock-cache-timestamp)
+(defvar fast-lock-save-others t
+  "If non-nil, save Font Lock cache files irrespective of file owner.
+If nil, means only buffer files known to be owned by you can have associated
+Font Lock cache files saved.  Ownership may be unknown for networked files.")
+
+(defvar fast-lock-save-faces
+  ;; Since XEmacs uses extents for everything, we have to pick the right ones.
+  ;; In XEmacs 19.12 we can't identify which text properties are font-lock's.
+  (if (save-match-data (string-match "XEmacs" (emacs-version)))
+      '(font-lock-string-face font-lock-doc-string-face font-lock-type-face
+	font-lock-function-name-face font-lock-comment-face
+	font-lock-keyword-face)
+    ;; For Emacs 19.29 I don't think this is generally necessary.
+    ;(mapcar 'eval (mapcar 'car font-lock-face-attributes))
+    )
+  "A list of faces that will be saved in a Font Lock cache file.
+If nil, means information for all faces will be saved.")
 
-;; Functions:
+;; User Functions:
 
+;;;###autoload
 (defun fast-lock-mode (&optional arg)
   "Toggle Fast Lock mode.
 With arg, turn Fast Lock mode on if and only if arg is positive and the buffer
-is associated with a file.
+is associated with a file.  Enable it automatically in your `~/.emacs' by:
+
+ (add-hook 'font-lock-mode-hook 'turn-on-fast-lock)
 
 If Fast Lock mode is enabled, and the current buffer does not contain any text
-properties, any associated font lock cache is used (by `fast-lock-read-cache')
-if the same `font-lock-keywords' were used for the cache as you are using.
+properties, any associated Font Lock cache is used if its timestamp matches the
+buffer's file, and its `font-lock-keywords' match those that you are using.
+
+Font Lock caches may be saved:
+ - When you save the file's buffer.
+ - When you kill an unmodified file's buffer.
+ - When you exit Emacs, for all unmodified or saved buffers.
+Depending on the value of `fast-lock-save-events'.
+See also the commands `fast-lock-read-cache' and `fast-lock-save-cache'.
 
-Font lock caches will be saved:
- - For all buffers with Fast Lock mode enabled when you exit from Emacs.
- - For a buffer with Fast Lock mode enabled when you kill the buffer.
-Saving is done by `fast-lock-save-cache' and `fast-lock-save-caches'.
+Use \\[font-lock-fontify-buffer] to fontify the buffer if the cache is bad.
 
-Various methods of control are provided for the font lock cache.  In general,
+Various methods of control are provided for the Font Lock cache.  In general,
 see variable `fast-lock-cache-directories' and function `fast-lock-cache-name'.
-For saving, see variables `fast-lock-save-others' and `fast-lock-save-size'."
+For saving, see variables `fast-lock-minimum-size', `fast-lock-save-events',
+`fast-lock-save-others' and `fast-lock-save-faces'.
+
+Use \\[fast-lock-submit-bug-report] to send bug reports or feedback."
   (interactive "P")
   (set (make-local-variable 'fast-lock-mode)
        (and (buffer-file-name)
 	    (if arg (> (prefix-numeric-value arg) 0) (not fast-lock-mode))))
-  (if (and fast-lock-mode (not font-lock-fontified))
-      (fast-lock-read-cache)))
+  (if (and fast-lock-mode (not font-lock-mode))
+      ;; Turned on `fast-lock-mode' rather than using `font-lock-mode-hook'.
+      (progn
+	(add-hook 'font-lock-mode-hook 'turn-on-fast-lock)
+	(font-lock-mode 1))
+    ;; Let's get down to business.
+    (set (make-local-variable 'fast-lock-cache-timestamp) nil)
+    (set (make-local-variable 'fast-lock-cache-filename) nil)
+    (if (and fast-lock-mode (not font-lock-fontified))
+	(fast-lock-read-cache))))
 
 (defun fast-lock-read-cache ()
-  "Read the font lock cache for the current buffer.
-Returns t if the font lock cache file is read.
+  "Read the Font Lock cache for the current buffer.
 
-The following criteria must be met for a font lock cache file to be read:
+The following criteria must be met for a Font Lock cache file to be read:
  - Fast Lock mode must be turned on in the buffer.
+ - The buffer must not be modified.
  - The buffer's `font-lock-keywords' must match the cache's.
  - The buffer file's timestamp must match the cache's.
  - Criteria imposed by `fast-lock-cache-directories'.
 
-See also `fast-lock-save-cache' and `fast-lock-cache-name'."
+See `fast-lock-mode'."
   (interactive)
-  (let ((directories fast-lock-cache-directories) directory
-	(modified (buffer-modified-p))
+  (let ((directories fast-lock-cache-directories)
+	(modified (buffer-modified-p)) (inhibit-read-only t)
 	(fontified font-lock-fontified))
+    (setq fast-lock-cache-filename nil)
     (set (make-local-variable 'font-lock-fontified) nil)
     ;; Keep trying directories until fontification is turned off.
     (while (and directories (not font-lock-fontified))
-      (setq directory (fast-lock-cache-directory (car directories) nil)
-	    directories (cdr directories))
-      (if directory
-	  (condition-case nil
-	      (load (fast-lock-cache-name directory) t t t)
-	    (error nil) (quit nil))))
+      (let* ((directory (fast-lock-cache-directory (car directories) nil))
+	     (file (and directory (fast-lock-cache-name directory))))
+	(condition-case nil
+	    (and file (file-readable-p file) (load file t t t))
+	  (error nil) (quit nil))
+	(setq directories (cdr directories))))
     (set-buffer-modified-p modified)
     (or font-lock-fontified (setq font-lock-fontified fontified))))
 
 (defun fast-lock-save-cache (&optional buffer)
-  "Save the font lock cache of BUFFER or the current buffer.
-Returns t if the font lock cache file is saved.
+  "Save the Font Lock cache of BUFFER or the current buffer.
 
-The following criteria must be met for a font lock cache file to be saved:
+The following criteria must be met for a Font Lock cache file to be saved:
  - Fast Lock mode must be turned on in the buffer.
- - The buffer must be at least `fast-lock-save-size' bytes long.
+ - The event must be one of `fast-lock-save-events'.
+ - The buffer must be at least `fast-lock-minimum-size' bytes long.
  - The buffer file must be owned by you, or `fast-lock-save-others' must be t.
  - The buffer must contain at least one `face' text property.
- - The buffer file's timestamp must be different than its associated text
-   properties file's timestamp.
+ - The buffer must not be modified.
+ - The buffer file's timestamp must be the same as the file's on disk.
+ - The on disk file's timestamp must be different than the buffer's cache.
  - Criteria imposed by `fast-lock-cache-directories'.
 
-See also `fast-lock-save-caches', `fast-lock-read-cache' and `fast-lock-mode'."
+See `fast-lock-mode'."
   (interactive)
-  (let* ((bufile (buffer-file-name buffer))
-	 (buatts (and bufile (file-attributes bufile)))
-	 (bufile-timestamp (nth 5 buatts))
-	 (bufuid (nth 2 buatts)) (saved nil))
-    (save-excursion
-      (and buffer (set-buffer buffer))
+  (save-excursion
+    (and buffer (set-buffer buffer))
+    (let ((file-timestamp (visited-file-modtime)) (saved nil))
       (if (and fast-lock-mode
-	       ;; Only save if the timestamp of the file has changed.
-	       (not (equal fast-lock-cache-timestamp bufile-timestamp))
-	       ;; User's restrictions?
-	       (or fast-lock-save-others (eq (user-uid) bufuid))
-	       (<= (or fast-lock-save-size 0) (buffer-size))
-	       ;; Only save if there are properties to save.
+	       ;;
+	       ;; "Only save if the buffer matches the file, the file has
+	       ;; changed, and it was changed by the current emacs session."
+	       ;;
+	       ;; Only save if the buffer is not modified,
+	       ;; (i.e., so we don't save for something not on disk)
+	       (not (buffer-modified-p))
+	       ;; and the file's timestamp is the same as the buffer's,
+	       ;; (i.e., someone else hasn't written the file in the meantime)
+	       (verify-visited-file-modtime (current-buffer))
+	       ;; and the file's timestamp is different from the cache's.
+	       ;; (i.e., a save has occurred since the cache was read)
+	       (not (equal fast-lock-cache-timestamp file-timestamp))
+	       ;;
+	       ;; Only save if user's restrictions are satisfied.
+	       (or (not fast-lock-minimum-size)
+		   (<= fast-lock-minimum-size (buffer-size)))
+	       (or fast-lock-save-others
+		   (eq (user-uid) (nth 2 (file-attributes buffer-file-name))))
+	       ;;
+	       ;; Only save if there are `face' properties to save.
 	       (text-property-not-all (point-min) (point-max) 'face nil))
-	  (let ((directories fast-lock-cache-directories) directory)
-	    (while (and directories (not saved))
-	      (setq directory (fast-lock-cache-directory (car directories) t)
-		    directories (cdr directories))
-	      (if directory
-		  (setq saved (fast-lock-save-cache-data
-			       directory bufile-timestamp))))))
-      ;; Set the buffer's timestamp if saved.
-      (and saved (setq fast-lock-cache-timestamp bufile-timestamp)))
-    saved))
-
-(defun fast-lock-save-cache-data (directory timestamp)
-  ;; Save the file with the timestamp, if we can, in the given directory, as:
-  ;; (fast-lock-cache-data Version=2 TIMESTAMP font-lock-keywords PROPERTIES).
-  (let ((buname (buffer-name))
-	(tpfile (fast-lock-cache-name directory))
-	(saved nil))
-    (if (file-writable-p tpfile)
-	(let ((tpbuf (generate-new-buffer " *fast-lock*")))
-	  (message "Saving %s font lock cache..." buname)
-	  (unwind-protect
-	      (save-excursion
-		(print (list 'fast-lock-cache-data 2
-			     (list 'quote timestamp)
-			     (list 'quote font-lock-keywords)
-			     (list 'quote (fast-lock-get-face-properties)))
-		       tpbuf)
-		(set-buffer tpbuf)
-		(write-region (point-min) (point-max) tpfile nil 'quietly)
-		(setq saved t))
-	    (kill-buffer tpbuf))
-	  (message "Saving %s font lock cache... done." buname)))
-    saved))
-
-;; Miscellaneous functions:
-
+	  ;; Try each directory until we manage to save or the user quits.
+	  (let ((directories fast-lock-cache-directories))
+	    (while (and directories (memq saved '(nil error)))
+	      (let* ((dir (fast-lock-cache-directory (car directories) t))
+		     (file (and dir (fast-lock-cache-name dir))))
+		(if (and file (file-writable-p file))
+		    (setq saved (fast-lock-save-cache-1 file file-timestamp)))
+		(setq directories (cdr directories)))))))))
+
+;;;###autoload
 (defun turn-on-fast-lock ()
   "Unconditionally turn on Fast Lock mode."
   (fast-lock-mode 1))
+
+;;; API Functions:
+
+(defun fast-lock-after-fontify-buffer ()
+  ;; Delete the Font Lock cache file used to restore fontification, if any.
+  (if fast-lock-cache-filename
+      (if (file-writable-p fast-lock-cache-filename)
+	  (delete-file fast-lock-cache-filename)
+	(message "File %s font lock cache cannot be deleted" (buffer-name))))
+  ;; Flag so that a cache will be saved later even if the file is never saved.
+  (setq fast-lock-cache-timestamp nil))
+
+;; Miscellaneous Functions:
+
+(defun fast-lock-after-save-hook ()
+  ;; Do `fast-lock-save-cache' if `save-buffer' is on `fast-lock-save-events'.
+  (if (memq 'save-buffer fast-lock-save-events)
+      (fast-lock-save-cache)))
+
+(defun fast-lock-kill-buffer-hook ()
+  ;; Do `fast-lock-save-cache' if `kill-buffer' is on `fast-lock-save-events'.
+  (if (memq 'kill-buffer fast-lock-save-events)
+      (fast-lock-save-cache)))
 
-(defun fast-lock-save-caches ()
-  "Save the font lock caches of all buffers.
-Returns list of cache save success of buffers in `buffer-list'.
-See `fast-lock-save-cache' for details of save criteria."
-  (mapcar 'fast-lock-save-cache (buffer-list)))
+(defun fast-lock-kill-emacs-hook ()
+  ;; Do `fast-lock-save-cache's if `kill-emacs' is on `fast-lock-save-events'.
+  (if (memq 'kill-emacs fast-lock-save-events)
+      (mapcar 'fast-lock-save-cache (buffer-list))))
 
 (defun fast-lock-cache-directory (directory create)
   "Return usable directory based on DIRECTORY.
 Returns nil if the directory does not exist, or, if CREATE non-nil, cannot be
 created.  DIRECTORY may be a string or a cons pair of the form (REGEXP . DIR).
 See `fast-lock-cache-directories'."
-  (let ((dir (cond ((not buffer-file-name)
-		    nil)
-		   ((stringp directory)
-		    directory)
-		   (t
-		    (let ((bufile (expand-file-name
-				   (abbreviate-file-name
-				    (file-truename buffer-file-name))))
-			  (case-fold-search nil))
-		      (if (string-match (car directory) bufile)
-			  (cdr directory)))))))
+  (let ((dir
+	 (cond ((not buffer-file-name)
+		;; Should never be nil, but `crypt++' screws it up.
+		nil)
+	       ((stringp directory)
+		;; Just a directory.
+		directory)
+	       (t
+		;; A directory iff the file name matches the regexp.
+		(let ((bufile (expand-file-name buffer-file-truename))
+		      (case-fold-search nil))
+		  (if (save-match-data (string-match (car directory) bufile))
+		      (cdr directory)))))))
     (cond ((not dir)
 	   nil)
-	  ((not create)
-	   (and (file-accessible-directory-p dir) dir))
-	  (t
-	   (if (file-accessible-directory-p dir)
-	       dir
-	     (condition-case nil (make-directory dir t) (error nil))
-	     (and (file-accessible-directory-p dir) dir))))))
+	  ((file-accessible-directory-p dir)
+	   dir)
+	  (create
+	   (condition-case nil
+	       (progn (make-directory dir t) dir)
+	     (error nil))))))
 
 (defun fast-lock-cache-name (directory)
   "Return full cache path name using caching DIRECTORY.
@@ -280,8 +329,7 @@ characters, and appended with `.flc'.
 See `fast-lock-mode'."
   (if (string-equal directory ".")
       (concat buffer-file-name ".flc")
-    (let* ((bufile (expand-file-name
-		    (abbreviate-file-name (file-truename buffer-file-name))))
+    (let* ((bufile (expand-file-name buffer-file-truename))
 	   (chars-alist
 	    (if (eq system-type 'emx)
 		'((?/ . (?#)) (?# . (?# ?#)) (?: . (?\;)) (?\; . (?\; ?\;)))
@@ -293,149 +341,193 @@ See `fast-lock-mode'."
        (mapconcat 'char-to-string (apply 'append (mapcar mapchars bufile)) "")
        ".flc"))))
 
-;; Font lock cache processing functions:
+;; Font Lock Cache Processing Functions:
+
+(defun fast-lock-save-cache-1 (file timestamp)
+  ;; Save the FILE with the TIMESTAMP as:
+  ;; (fast-lock-cache-data Version=2 TIMESTAMP font-lock-keywords PROPERTIES).
+  ;; Returns non-nil if a save was attempted to a writable cache file.
+  (let ((tpbuf (generate-new-buffer " *fast-lock*"))
+	(buname (buffer-name)) (saved t))
+    (message "Saving %s font lock cache..." buname)
+    (condition-case nil
+	(save-excursion
+	  (print (list 'fast-lock-cache-data 2
+		       (list 'quote timestamp)
+		       (list 'quote font-lock-keywords)
+		       (list 'quote (fast-lock-get-face-properties)))
+		 tpbuf)
+	  (set-buffer tpbuf)
+	  (write-region (point-min) (point-max) file nil 'quietly)
+	  (setq fast-lock-cache-timestamp timestamp
+		fast-lock-cache-filename file))
+      (error (setq saved 'error)) (quit (setq saved 'quit)))
+    (kill-buffer tpbuf)
+    (message "Saving %s font lock cache... %s." buname
+	     (cond ((eq saved 'error) "failed")
+		   ((eq saved 'quit) "aborted")
+		   (t "done")))
+    ;; We return non-nil regardless of whether a failure occurred.
+    saved))
 
 (defun fast-lock-cache-data (version timestamp keywords properties
 			     &rest ignored)
-  ;; Use the font lock cache PROPERTIES if we're using cache VERSION format 2,
+  ;; Change from (HIGH LOW) for back compatibility.  Remove for version 3!
+  (if (consp (cdr-safe timestamp)) (setcdr timestamp (nth 1 timestamp)))
+  ;; Compile KEYWORDS and `font-lock-keywords' in case one is and one isn't.
+  (let ((current font-lock-keywords))
+    (setq keywords (font-lock-compile-keywords keywords)
+	  font-lock-keywords (font-lock-compile-keywords current)))
+  ;; Use the Font Lock cache PROPERTIES if we're using cache VERSION format 2,
   ;; the current buffer's file timestamp matches the TIMESTAMP, and the current
   ;; buffer's font-lock-keywords are the same as KEYWORDS.
-  (let ((buf-timestamp (nth 5 (file-attributes buffer-file-name)))
-	(buname (buffer-name)) (inhibit-read-only t) (loaded t))
+  (let ((buf-timestamp (visited-file-modtime))
+	(buname (buffer-name)) (loaded t))
     (if (or (/= version 2)
+	    (buffer-modified-p)
 	    (not (equal timestamp buf-timestamp))
 	    (not (equal keywords font-lock-keywords)))
 	(setq loaded nil)
       (message "Loading %s font lock cache..." buname)
       (condition-case nil
 	  (fast-lock-set-face-properties properties)
-	(error (setq loaded nil)) (quit (setq loaded nil)))
-      (message "Loading %s font lock cache... done." buname))
+	(error (setq loaded 'error)) (quit (setq loaded 'quit)))
+      (message "Loading %s font lock cache... %s." buname
+	       (cond ((eq loaded 'error) "failed")
+		     ((eq loaded 'quit) "aborted")
+		     (t "done"))))
     ;; If we used the text properties, stop fontification and keep timestamp.
-    (setq font-lock-fontified loaded
-	  fast-lock-cache-timestamp (and loaded timestamp))))
-
-(defun fast-lock-get-face-properties (&optional buffer)
-  "Return a list of all `face' text properties in BUFFER.
+    ;; Kludge warning: `file' comes from sole caller `fast-lock-read-cache'.
+    (setq font-lock-fontified (eq loaded t)
+	  fast-lock-cache-timestamp (and (eq loaded t) timestamp)
+	  fast-lock-cache-filename (and (eq loaded t) file))))
+
+;; Text Properties Processing Functions:
+
+;; This is faster, but fails if adjacent characters have different `face' text
+;; properties.  Maybe that's why I dropped it in the first place?
+;(defun fast-lock-get-face-properties ()
+;  "Return a list of all `face' text properties in the current buffer.
+;Each element of the list is of the form (VALUE START1 END1 START2 END2 ...)
+;where VALUE is a `face' property value and STARTx and ENDx are positions."
+;  (save-restriction
+;    (widen)
+;    (let ((start (text-property-not-all (point-min) (point-max) 'face nil))
+;	  (limit (point-max)) end properties value cell)
+;      (while start
+;	(setq end (next-single-property-change start 'face nil limit)
+;	      value (get-text-property start 'face))
+;	;; Make, or add to existing, list of regions with same `face'.
+;	(if (setq cell (assq value properties))
+;	    (setcdr cell (cons start (cons end (cdr cell))))
+;	  (setq properties (cons (list value start end) properties)))
+;	(setq start (next-single-property-change end 'face)))
+;      properties)))
+
+(defun fast-lock-get-face-properties ()
+  "Return a list of all `face' text properties in the current buffer.
 Each element of the list is of the form (VALUE START1 END1 START2 END2 ...)
-where VALUE is a `face' property value and STARTx and ENDx are positions."
-  (save-excursion
-    (and buffer (set-buffer buffer))
-    (save-restriction
-      (widen)
-      (let ((start (text-property-not-all (point-min) (point-max) 'face nil))
-	    (limit (point-max)) end properties value cell)
-	(while start
-	  (setq end (next-single-property-change start 'face nil limit)
-		value (get-text-property start 'face))
-	  ;; Make or add to existing list of regions with same `face' property.
-	  (if (setq cell (assq value properties))
-	      (setcdr cell (cons start (cons end (cdr cell))))
-	    (setq properties (cons (list value start end) properties)))
-	  (setq start (next-single-property-change end 'face)))
-	properties))))
-
-(defun fast-lock-set-face-properties (properties &optional buffer)
-  "Set all `face' text properties to PROPERTIES in BUFFER.
-Any existing `face' text properties are removed first.  Leaves BUFFER modified.
+where VALUE is a `face' property value and STARTx and ENDx are positions.
+Only those `face' VALUEs in `fast-lock-save-faces' are returned."
+  (save-restriction
+    (widen)
+    (let ((faces (or fast-lock-save-faces (face-list))) (limit (point-max))
+	  properties regions face start end)
+      (while faces
+	(setq face (car faces) faces (cdr faces) regions () end (point-min))
+	;; Make a list of start/end regions with `face' property face.
+	(while (setq start (text-property-any end limit 'face face))
+	  (setq end (or (text-property-not-all start limit 'face face) limit)
+		regions (cons start (cons end regions))))
+	;; Add `face' face's regions, if any, to properties.
+	(if regions (setq properties (cons (cons face regions) properties))))
+      properties)))
+
+(defun fast-lock-set-face-properties (properties)
+  "Set all `face' text properties to PROPERTIES in the current buffer.
+Any existing `face' text properties are removed first.  Leaves buffer modified.
 See `fast-lock-get-face-properties' for the format of PROPERTIES."
-  (save-excursion
-    (and buffer (set-buffer buffer))
-    (save-restriction
-      (widen)
-      (font-lock-unfontify-region (point-min) (point-max))
-      (while properties
-	(let ((plist (list 'face (car (car properties))))
-	      (regions (cdr (car properties))))
-	  ;; Set the `face' property for each start/end region.
-	  (while regions
-	    (set-text-properties (nth 0 regions) (nth 1 regions) plist buffer)
-	    (setq regions (nthcdr 2 regions)))
-	  (setq properties (cdr properties)))))))
+  (save-restriction
+    (widen)
+    (font-lock-unfontify-region (point-min) (point-max))
+    (while properties
+      (let ((plist (list 'face (car (car properties))))
+	    (regions (cdr (car properties))))
+	;; Set the `face' property for each start/end region.
+	(while regions
+	  (set-text-properties (nth 0 regions) (nth 1 regions) plist)
+	  (setq regions (nthcdr 2 regions)))
+	(setq properties (cdr properties))))))
 
-;; Functions for Lucid:
+;; Functions for XEmacs:
 
-(or (fboundp 'face-list)
-    (defalias 'face-list 'list-faces))
-
-(if (save-match-data (string-match "Lucid" (emacs-version)))
-    ;; This is about a bazillion times faster at generating the cache in Lucid.
-    (defun fast-lock-get-face-properties (&optional buffer)
-      "Return a list of all `face' text properties in BUFFER.
+(if (save-match-data (string-match "XEmacs" (emacs-version)))
+    ;; It would be better to use XEmacs 19.12's `map-extents' over extents with
+    ;; `font-lock' property, but `face' properties are on different extents.
+    (defun fast-lock-get-face-properties ()
+      "Return a list of all `face' text properties in the current buffer.
 Each element of the list is of the form (VALUE START1 END1 START2 END2 ...)
-where VALUE is a `face' property value and STARTx and ENDx are positions."
-      (save-excursion
-	(and buffer (set-buffer buffer))
-	(save-restriction
-	  (widen)
-	  (let ((properties ()))
-	    (map-extents
-	     (function (lambda (extent ignore)
-	      (let* ((face (extent-face extent))
-		     (start (extent-start-position extent))
-		     (end (extent-end-position extent))
-		     (facedata (assoc face properties)))
-		(if facedata
-		    ;; Prepend the new start and end points onto the list.
-		    (setcdr facedata (cons start (cons end (cdr facedata))))
-		  (setq properties (cons (list face start end) properties)))
+where VALUE is a `face' property value and STARTx and ENDx are positions.
+Only those `face' VALUEs in `fast-lock-save-faces' are returned."
+      (save-restriction
+	(widen)
+	(let ((properties ()) cell)
+	  (map-extents
+	   (function
+	    (lambda (extent ignore)
+	      (let ((value (extent-face extent)))
+		;; We're only interested if it's one of `fast-lock-save-faces'.
+		(if (and value (or (null fast-lock-save-faces)
+				   (memq value fast-lock-save-faces)))
+		    (let ((start (extent-start-position extent))
+			  (end (extent-end-position extent)))
+		      ;; Make or add to existing list of regions with the same
+		      ;; `face' property value.
+		      (if (setq cell (assq value properties))
+			  (setcdr cell (cons start (cons end (cdr cell))))
+			(setq properties (cons (list value start end)
+					       properties)))))
 		;; Return nil to keep `map-extents' going.
 		nil))))
-	    properties)))))
+	  properties))))
 
-(if (save-match-data (string-match "Lucid" (emacs-version)))
-    ;; This is faster at using the cache in Lucid.
-    (defun fast-lock-set-face-properties (properties &optional buffer)
-      "Set all `face' text properties to PROPERTIES in BUFFER.
-Any existing `face' text properties are removed first.  Leaves BUFFER modified.
+(if (save-match-data (string-match "XEmacs" (emacs-version)))
+    ;; Make extents just like XEmacs's font-lock.el does.
+    (defun fast-lock-set-face-properties (properties)
+      "Set all `face' text properties to PROPERTIES in the current buffer.
+Any existing `face' text properties are removed first.
 See `fast-lock-get-face-properties' for the format of PROPERTIES."
-      (save-excursion
-	(and buffer (set-buffer buffer))
-	(save-restriction
-	  (widen)
-	  (font-lock-unfontify-region (point-min) (point-max))
-	  (while properties
-	    (let ((property (car (car properties)))
-		  (regions (cdr (car properties))) extent)
-	      ;; Set the `face' property for each start/end region.
-	      (while regions
-		(setq extent (make-extent (nth 0 regions) (nth 1 regions))
-		      regions (nthcdr 2 regions))
-		(set-extent-face extent property)
-		(set-extent-property extent 'text-prop 'face))
-	      (setq properties (cdr properties))))))))
-
-(if (and (boundp 'emacs-minor-version) (< emacs-minor-version 12))
-    ;; Must be [LX]Emacs; fix the 19.11 (at least) `text-property-not-all' bug.
-    (defun text-property-not-all (start end prop value &optional buffer)
-      "Check text from START to END to see if PROP is ever not `eq' to VALUE.
-If so, return the position of the first character whose PROP is not
-`eq' to VALUE.  Otherwise, return nil."
-      (let ((maxend start))
-	(map-extents
-	 (function
-	  (lambda (e ignore)
-	    ;;### no, actually, this is harder.  We need to collect all props
-	    ;; for a given character, and then determine whether no extent
-	    ;; contributes the given value.  Doing this without consing lots
-	    ;; of lists is the tricky part.
-	    (if (not (eq value (extent-property e prop)))
-		(max start maxend)
-	      (setq maxend (extent-end-position e))
-	      nil)))
-	 nil start end buffer))))
+      (save-restriction
+	(widen)
+	(font-lock-unfontify-region (point-min) (point-max))
+	(while properties
+	  (let ((face (car (car properties)))
+		(regions (cdr (car properties))))
+	    ;; Set the `face' property, etc., for each start/end region.
+	    (while regions
+	      (font-lock-set-face (nth 0 regions) (nth 1 regions) face)
+	      (setq regions (nthcdr 2 regions)))
+	    (setq properties (cdr properties)))))))
+
+(or (fboundp 'font-lock-compile-keywords)
+    (defalias 'font-lock-compile-keywords 'identity))
 
 ;; Install ourselves:
 
+;; We don't install ourselves on `font-lock-mode-hook' as packages with similar
+;; functionality exist, and fast-lock.el should be dumpable.
+(add-hook 'after-save-hook 'fast-lock-after-save-hook)
+(add-hook 'kill-buffer-hook 'fast-lock-kill-buffer-hook)
+(add-hook 'kill-emacs-hook 'fast-lock-kill-emacs-hook)
+
+;; Maybe save on the modeline?
+;;(setcdr (assq 'font-lock-mode minor-mode-alist) '(" Fast"))
+
 (or (assq 'fast-lock-mode minor-mode-alist)
     (setq minor-mode-alist (cons '(fast-lock-mode " Fast") minor-mode-alist)))
 
-(add-hook 'kill-buffer-hook 'fast-lock-save-cache)
-(add-hook 'kill-emacs-hook 'fast-lock-save-caches)
-
 ;; Provide ourselves:
 
 (provide 'fast-lock)
 
 ;;; fast-lock.el ends here
-
-- 
2.39.2