]> code.delx.au - gnu-emacs/blobdiff - lisp/ediff-util.el
(sgml-tag-alist): Doc fix.
[gnu-emacs] / lisp / ediff-util.el
index 8d0f7395149cf32d1b0e7957aaa53d58c1cc771e..99d013616246b25de2c72f7861bef805cf6eb901 100644 (file)
@@ -1,8 +1,8 @@
 ;;; ediff-util.el --- the core commands and utilities of ediff
 
-;; Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 01 Free Software Foundation, Inc.
+;; Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 01, 02 Free Software Foundation, Inc.
 
-;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+;; Author: Michael Kifer <kifer@cs.stonybrook.edu>
 
 ;; This file is part of GNU Emacs.
 
@@ -40,6 +40,8 @@
 (defvar mark-active)
 (defvar ediff-emacs-p)
 
+(defvar ediff-after-quit-hook-internal nil)
+
 (eval-when-compile
   (let ((load-path (cons (expand-file-name ".") load-path)))
     (or (featurep 'ediff-init)
@@ -231,7 +233,7 @@ to invocation.")
   (define-key ediff-mode-map "wb"  'ediff-save-buffer)
   (define-key ediff-mode-map "wd"  'ediff-save-buffer)
   (define-key ediff-mode-map "="   'ediff-inferior-compare-regions)
-  (if (fboundp 'ediff-show-patch-diagnostics)
+  (if (and (fboundp 'ediff-show-patch-diagnostics) (ediff-patch-job))
       (define-key ediff-mode-map "P"  'ediff-show-patch-diagnostics))
   (if ediff-3way-job
       (progn
@@ -294,8 +296,11 @@ to invocation.")
       (make-local-variable 'ediff-window-setup-function)
       (make-local-variable 'ediff-keep-variants)
 
-      (make-local-hook 'ediff-after-quit-hook-internal)
-      
+      (ediff-cond-compile-for-xemacs-or-emacs
+       (make-local-hook 'ediff-after-quit-hook-internal) ; xemacs form
+       nil ; emacs form
+       )
+
       ;; unwrap set up parameters passed as argument
       (while setup-parameters
        (set (car (car setup-parameters)) (cdr (car setup-parameters)))
@@ -317,9 +322,13 @@ to invocation.")
       (if (string-match "buffer" (symbol-name ediff-job-name))
          (setq ediff-keep-variants t))
 
-      (make-local-hook 'pre-command-hook)
+      (ediff-cond-compile-for-xemacs-or-emacs
+       (make-local-hook 'pre-command-hook) ; xemacs form
+       nil                                 ; emacs form
+       )
+
       (if (ediff-window-display-p)
-         (add-hook 'pre-command-hook 'ediff-spy-after-mouse nil t))
+         (add-hook 'pre-command-hook 'ediff-spy-after-mouse nil 'local))
       (setq ediff-mouse-pixel-position (mouse-pixel-position))
       
       ;; adjust for merge jobs
@@ -349,6 +358,7 @@ to invocation.")
              (set-buffer buffer-C)
              (insert-buffer buf)
              (funcall (ediff-with-current-buffer buf major-mode))
+             (widen) ; merge buffer is always widened
              (add-hook 'local-write-file-hooks 'ediff-set-merge-mode nil t)
              )))
       (setq buffer-read-only nil    
@@ -449,6 +459,10 @@ to invocation.")
       (if ediff-3way-job
          (ediff-with-current-buffer ediff-buffer-C
            (ediff-nuke-selective-display)
+           ;; the merge bufer should never be narrowed
+           ;; (it can happen if it is on rmail-mode or similar)
+           (if (ediff-with-current-buffer control-buffer ediff-merge-job)
+               (widen))
            (run-hooks 'ediff-prepare-buffer-hook)
            ;; add control-buffer to the list of sessions
            (or (memq control-buffer ediff-this-buffer-ediff-sessions)
@@ -456,7 +470,8 @@ to invocation.")
                      (cons control-buffer
                            ediff-this-buffer-ediff-sessions))) 
            (if ediff-make-buffers-readonly-at-startup
-               (setq buffer-read-only t))
+               (setq buffer-read-only t)
+             (setq buffer-read-only nil))
            ))
 
       (if (ediff-buffer-live-p ediff-ancestor-buffer)
@@ -470,7 +485,7 @@ to invocation.")
                            ediff-this-buffer-ediff-sessions)))
            ))
       
-      ;; must come after setting up  ediff-narrow-bounds AND after
+      ;; the following must be after setting up  ediff-narrow-bounds AND after
       ;; nuking selective display
       (funcall ediff-setup-diff-regions-function file-A file-B file-C)
       (setq ediff-number-of-differences (length ediff-difference-vector-A))
@@ -573,6 +588,7 @@ to invocation.")
     (if (stringp ediff-merge-store-file)
        (progn
          ;; save before leaving ctl buffer
+         (ediff-verify-file-merge-buffer ediff-merge-store-file)
          (setq merge-buffer-file ediff-merge-store-file) 
          (ediff-with-current-buffer ediff-buffer-C
            (set-visited-file-name merge-buffer-file))))
@@ -894,36 +910,40 @@ Does nothing if file-A and file-B are in different frames."
 On a dumb terminal, switches between ASCII highlighting and no highlighting." 
   (interactive)
   (ediff-barf-if-not-control-buffer)
-  (if (not (ediff-has-face-support-p))
-      (if (eq ediff-highlighting-style 'ascii)
-         (progn
-           (message "ASCII highlighting flags removed")
-           (ediff-unselect-and-select-difference ediff-current-difference
-                                                 'unselect-only)
-           (setq ediff-highlighting-style 'off))
-       (ediff-unselect-and-select-difference ediff-current-difference
-                                             'select-only))
-    (ediff-unselect-and-select-difference ediff-current-difference
-                                         'unselect-only)
-    ;; cycle through highlighting
-    (cond ((and ediff-use-faces ediff-highlight-all-diffs)
-          (message "Unhighlighting unselected difference regions")
-          (setq ediff-highlight-all-diffs nil))
-         (ediff-use-faces
-          (message "Highlighting with ASCII flags")
-          (setq ediff-use-faces nil))
-         (t
-          (message "Re-highlighting all difference regions")
-          (setq ediff-use-faces t
-                ediff-highlight-all-diffs t)))
-                
-    (if (and ediff-use-faces ediff-highlight-all-diffs)
-       (ediff-paint-background-regions)
-      (ediff-paint-background-regions 'unhighlight))
-    
-    (ediff-unselect-and-select-difference
-     ediff-current-difference 'select-only))
-  )
+
+  (ediff-unselect-and-select-difference
+   ediff-current-difference 'unselect-only)
+  ;; cycle through highlighting
+  (cond ((and ediff-use-faces
+             (ediff-has-face-support-p)
+             ediff-highlight-all-diffs)
+        (message "Unhighlighting unselected difference regions")
+        (setq ediff-highlight-all-diffs  nil
+              ediff-highlighting-style  'face))
+       ((or (and ediff-use-faces  (ediff-has-face-support-p)
+                 (eq ediff-highlighting-style 'face))       ; has face support
+            (and (not (ediff-has-face-support-p))           ; no face support
+                 (eq ediff-highlighting-style 'off)))
+        (message "Highlighting with ASCII flags")
+        (setq ediff-highlighting-style  'ascii
+              ediff-highlight-all-diffs  nil
+              ediff-use-faces            nil))
+       ((eq ediff-highlighting-style 'ascii)
+        (message "ASCII highlighting flags removed")
+        (setq ediff-highlighting-style  'off
+              ediff-highlight-all-diffs  nil))
+       ((ediff-has-face-support-p)   ; catch-all for cases with face support
+        (message "Re-highlighting all difference regions")
+        (setq ediff-use-faces            t
+              ediff-highlighting-style  'face
+              ediff-highlight-all-diffs  t)))
+  
+  (if (and ediff-use-faces ediff-highlight-all-diffs)
+      (ediff-paint-background-regions)
+    (ediff-paint-background-regions 'unhighlight))
+  
+  (ediff-unselect-and-select-difference
+   ediff-current-difference 'select-only))
 
   
 (defun ediff-toggle-autorefine ()
@@ -1324,9 +1344,13 @@ To change the default, set the variable `ediff-use-toolbar-p', which see."
   ;; will not re-appear after our cleanup here.  Is there a way
   ;; to do "push" and "pop" toolbars ?  --marcpa  
   (if (ediff-use-toolbar-p)
-      (progn
-       (set-specifier bottom-toolbar (list (selected-frame) nil))
-       (set-specifier bottom-toolbar-visible-p (list (selected-frame) nil)))))
+      (ediff-cond-compile-for-xemacs-or-emacs
+       (progn ; xemacs
+        (set-specifier bottom-toolbar (list (selected-frame) nil))
+        (set-specifier bottom-toolbar-visible-p (list (selected-frame) nil)))
+       nil  ; emacs
+       )
+    ))
 
 ;; If wants to use toolbar, make it.
 ;; If not, zero the toolbar for XEmacs.
@@ -1336,15 +1360,24 @@ To change the default, set the variable `ediff-use-toolbar-p', which see."
       (progn
        (setq frame (or frame (selected-frame)))
        (cond ((ediff-use-toolbar-p) ; this checks for XEmacs
-              (set-specifier
-               bottom-toolbar
-               (list frame (if (ediff-3way-comparison-job)
-                               ediff-toolbar-3way ediff-toolbar)))
-              (set-specifier bottom-toolbar-visible-p (list frame t)) 
-              (set-specifier bottom-toolbar-height
-                             (list frame ediff-toolbar-height)))
+              (ediff-cond-compile-for-xemacs-or-emacs
+               (progn ; xemacs
+                 (set-specifier
+                  bottom-toolbar
+                  (list frame (if (ediff-3way-comparison-job)
+                                  ediff-toolbar-3way ediff-toolbar)))
+                 (set-specifier bottom-toolbar-visible-p (list frame t)) 
+                 (set-specifier bottom-toolbar-height
+                                (list frame ediff-toolbar-height)))
+               nil ; emacs
+               )
+              )
              ((ediff-has-toolbar-support-p)
-              (set-specifier bottom-toolbar-height (list frame 0)))
+              (ediff-cond-compile-for-xemacs-or-emacs
+               (set-specifier bottom-toolbar-height (list frame 0)) ; xemacs
+               nil                                                  ; emacs
+               )
+              )
              ))
     ))
               
@@ -1905,8 +1938,8 @@ determine the source and the target buffers instead of the command keys."
 
   (let* ((key1 (aref keys 0))
         (key2 (aref keys 1))
-        (char1 (if (and ediff-xemacs-p (eventp key1)) (event-key key1) key1))
-        (char2 (if (and ediff-xemacs-p (eventp key1)) (event-key key2) key2))
+        (char1 (ediff-event-key key1))
+        (char2 (ediff-event-key key2))
         ediff-verbose-p)
     (ediff-copy-diff ediff-current-difference
                     (ediff-char-to-buftype char1)
@@ -2378,7 +2411,7 @@ temporarily reverses the meaning of this variable."
 
   (ediff-delete-temp-files)
                                  
-  ;; Restore visibility range.  This affects only ediff-*-regions/windows.
+  ;; Restore the visibility range.  This affects only ediff-*-regions/windows.
   ;; Since for other job names ediff-visible-region sets
   ;; ediff-visible-bounds to ediff-wide-bounds, the settings below are
   ;; ignored for such jobs.
@@ -2460,11 +2493,12 @@ temporarily reverses the meaning of this variable."
 
   (run-hooks 'ediff-cleanup-hook)
 
-  ;; now kill buffers A/B/C, if requested
-  (let ((ediff-keep-variants ediff-keep-variants))
-    (if reverse-default-keep-variants
-       (setq ediff-keep-variants (not ediff-keep-variants)))
-    (or ediff-keep-variants (ediff-janitor 'ask)))
+  (ediff-janitor
+   'ask
+   ;; reverse-default-keep-variants is t if the user quits with a prefix arg
+   (if reverse-default-keep-variants
+       (not ediff-keep-variants)
+     ediff-keep-variants))
 
   ;; one hook here is ediff-cleanup-mess, which kills the control buffer and
   ;; other auxiliary buffers. we made it into a hook to let the users do their
@@ -2546,9 +2580,7 @@ temporarily reverses the meaning of this variable."
     (ediff-kill-buffer-carefully ctl-buf)
       
     (if (frame-live-p main-frame)
-       (progn
-         (select-frame main-frame)
-         (delete-other-windows)))
+       (select-frame main-frame))
     
     ;; display only if not visible
     (condition-case nil
@@ -2558,7 +2590,8 @@ temporarily reverses the meaning of this variable."
     (condition-case nil
        (or (ediff-get-visible-buffer-window buff-A)
            (progn
-             (if (ediff-get-visible-buffer-window buff-B)
+             (if (and (ediff-get-visible-buffer-window buff-B)
+                      (ediff-buffer-live-p buff-A))
                  (funcall ediff-split-window-function))
              (switch-to-buffer buff-A)))
       (error))
@@ -2566,8 +2599,9 @@ temporarily reverses the meaning of this variable."
        (condition-case nil
            (or (ediff-get-visible-buffer-window buff-C)
                (progn
-                 (if (or (ediff-get-visible-buffer-window buff-A)
-                         (ediff-get-visible-buffer-window buff-B))
+                 (if (and (or (ediff-get-visible-buffer-window buff-A)
+                              (ediff-get-visible-buffer-window buff-B))
+                          (ediff-buffer-live-p buff-C))
                      (funcall ediff-split-window-function))
                  (switch-to-buffer buff-C)
                  (balance-windows)))
@@ -2575,36 +2609,53 @@ temporarily reverses the meaning of this variable."
     (message "")
     ))
 
-(defun ediff-janitor (&optional ask)
+(defun ediff-janitor (ask keep-variants)
   "Kill buffers A, B, and, possibly, C, if these buffers aren't modified.
-In merge jobs, buffer C is never deleted.
-However, the side effect of cleaning up may be that you cannot compare the same
-buffer in two separate Ediff sessions: quitting one of them will delete this
-buffer in another session as well."
-  (or (not (ediff-buffer-live-p ediff-buffer-A))
-      (buffer-modified-p ediff-buffer-A)
-      (and ask
-          (not (y-or-n-p (format "Kill buffer A [%s]? "
-                                 (buffer-name ediff-buffer-A)))))
-      (ediff-kill-buffer-carefully ediff-buffer-A))
-  (or (not (ediff-buffer-live-p ediff-buffer-B))
-      (buffer-modified-p ediff-buffer-B)
-      (and ask
-          (not (y-or-n-p (format "Kill buffer B [%s]? "
-                                 (buffer-name ediff-buffer-B)))))
-      (ediff-kill-buffer-carefully ediff-buffer-B))
+In merge jobs, buffer C is not deleted here, but rather according to
+ediff-quit-merge-hook.
+A side effect of cleaning up may be that you should be careful when comparing
+the same buffer in two separate Ediff sessions: quitting one of them might
+delete this buffer in another session as well."
+  (ediff-dispose-of-variant-according-to-user
+   ediff-buffer-A 'A ask keep-variants)
+  (ediff-dispose-of-variant-according-to-user
+   ediff-buffer-B 'B ask keep-variants)
   (if ediff-merge-job  ; don't del buf C if merging--del ancestor buf instead
-      (or (not (ediff-buffer-live-p ediff-ancestor-buffer))
-         (buffer-modified-p ediff-ancestor-buffer)
-         (and ask
-              (not (y-or-n-p (format "Kill the ancestor buffer [%s]? "
-                                     (buffer-name ediff-ancestor-buffer)))))
-         (ediff-kill-buffer-carefully ediff-ancestor-buffer))
-    (or (not (ediff-buffer-live-p ediff-buffer-C))
-       (buffer-modified-p ediff-buffer-C)
-       (and ask (not (y-or-n-p (format "Kill buffer C [%s]? "
-                                       (buffer-name ediff-buffer-C)))))
-       (ediff-kill-buffer-carefully ediff-buffer-C))))
+      (ediff-dispose-of-variant-according-to-user
+       ediff-ancestor-buffer 'Ancestor ask keep-variants)
+    (ediff-dispose-of-variant-according-to-user
+     ediff-buffer-C 'C ask keep-variants)
+    ))
+
+;; Kill the variant buffer, according to user directives (ask, kill
+;; unconditionaly, keep)
+;; BUFF is the buffer, BUFF-TYPE is either 'A, or 'B, 'C, 'Ancestor
+(defun ediff-dispose-of-variant-according-to-user (buff bufftype ask keep-variants)
+  ;; if this is indirect buffer, kill it and substitute with direct buf
+  (if (and (ediff-buffer-live-p buff)
+          (ediff-with-current-buffer buff ediff-temp-indirect-buffer))
+      (let ((wind (ediff-get-visible-buffer-window buff))
+           (base (buffer-base-buffer buff))
+           (modified-p (buffer-modified-p buff)))
+       (if (and (window-live-p wind) (ediff-buffer-live-p base))
+           (set-window-buffer wind base))
+       ;; Kill indirect buffer even if it is modified, because the base buffer
+       ;; is still there. Note that if the base buffer is dead then so will be
+       ;; the indirect buffer
+       (ediff-with-current-buffer buff 
+         (set-buffer-modified-p nil))
+       (ediff-kill-buffer-carefully buff)
+       (ediff-with-current-buffer base
+         (set-buffer-modified-p modified-p)))
+    ;; otherwise, ask or use the value of keep-variants
+    (or (not (ediff-buffer-live-p buff))
+       keep-variants
+       (buffer-modified-p buff)
+       (and ask
+            (not (y-or-n-p (format "Kill buffer %S [%s]? "
+                                   bufftype (buffer-name buff)))))
+       (ediff-kill-buffer-carefully buff))
+    ))
 
 (defun ediff-maybe-save-and-delete-merge (&optional save-and-continue)
   "Default hook to run on quitting a merge job.
@@ -2623,7 +2674,7 @@ only if this merge job is part of a group, i.e., was invoked from within
        (ediff-autostore-merges ; fake ediff-autostore-merges, if necessary
         (if save-and-continue t ediff-autostore-merges)))
     (if ediff-autostore-merges
-       (cond ((stringp ediff-merge-store-file)
+       (cond ((stringp merge-store-file)
               ;; store, ask to delete
               (ediff-write-merge-buffer-and-maybe-kill
                ediff-buffer-C merge-store-file 'show-file save-and-continue))
@@ -2645,20 +2696,36 @@ only if this merge job is part of a group, i.e., was invoked from within
 (defun ediff-write-merge-buffer-and-maybe-kill (buf file
                                               &optional
                                               show-file save-and-continue)
-  (ediff-with-current-buffer buf
-    (if (or (not (file-exists-p file))
-           (y-or-n-p (format "File %s exists, overwrite? " file)))
-       (progn
-         (write-region (point-min) (point-max) file)
-         (if show-file
-             (progn
-               (message "Merge buffer saved in: %s" file)
-               (set-buffer-modified-p nil)
-               (sit-for 3)))
-         (if (and
-              (not save-and-continue)
-              (y-or-n-p "Merge buffer saved.  Now kill the buffer? "))
-             (ediff-kill-buffer-carefully buf))))))
+  (if (not (eq (find-buffer-visiting file) buf))
+      (let ((warn-message
+            (format "Another buffer is visiting file %s. Too dangerous to save the merge buffer"
+                    file)))
+       (beep)
+       (message warn-message)
+       (with-output-to-temp-buffer ediff-msg-buffer
+         (princ "\n\n")
+         (princ warn-message)
+         (princ "\n\n")
+         )
+       (sit-for 2))
+    (ediff-with-current-buffer buf
+      (if (or (not (file-exists-p file))
+             (y-or-n-p (format "File %s exists, overwrite? " file)))
+         (progn
+           ;;(write-region (point-min) (point-max) file)
+           (ediff-with-current-buffer buf
+             (set-visited-file-name file)
+             (save-buffer))
+           (if show-file
+               (progn
+                 (message "Merge buffer saved in: %s" file)
+                 (set-buffer-modified-p nil)
+                 (sit-for 3)))
+           (if (and
+                (not save-and-continue)
+                (y-or-n-p "Merge buffer saved.  Now kill the buffer? "))
+               (ediff-kill-buffer-carefully buf)))))
+    ))
 
 ;; The default way of suspending Ediff.
 ;; Buries Ediff buffers, kills all windows.
@@ -2846,23 +2913,22 @@ Hit \\[ediff-recenter] to reset the windows afterward."
           (ediff-buffer-live-p ediff-buffer-B)
           (ediff-valid-difference-p n))
       (progn
-       (if (and (ediff-has-face-support-p) ediff-use-faces)
-           (progn
-             (ediff-highlight-diff n)
-             (setq ediff-highlighting-style 'face))
-         (setq ediff-highlighting-style 'ascii)
-         (ediff-place-flags-in-buffer
-          'A ediff-buffer-A ediff-control-buffer n)
-         (ediff-place-flags-in-buffer
-          'B ediff-buffer-B ediff-control-buffer n)
-         (if ediff-3way-job
-             (ediff-place-flags-in-buffer
-              'C ediff-buffer-C ediff-control-buffer n))
-         (if (ediff-buffer-live-p ediff-ancestor-buffer)
-             (ediff-place-flags-in-buffer
-              'Ancestor ediff-ancestor-buffer
-              ediff-control-buffer n))
-         ) 
+       (cond
+           ((and (ediff-has-face-support-p) ediff-use-faces)
+              (ediff-highlight-diff n))
+           ((eq ediff-highlighting-style 'ascii)
+            (ediff-place-flags-in-buffer
+             'A ediff-buffer-A ediff-control-buffer n)
+            (ediff-place-flags-in-buffer
+             'B ediff-buffer-B ediff-control-buffer n)
+            (if ediff-3way-job
+                (ediff-place-flags-in-buffer
+                 'C ediff-buffer-C ediff-control-buffer n))
+            (if (ediff-buffer-live-p ediff-ancestor-buffer)
+                (ediff-place-flags-in-buffer
+                 'Ancestor ediff-ancestor-buffer
+                 ediff-control-buffer n))
+            )) 
                                       
        (ediff-install-fine-diff-if-necessary n)
        (run-hooks 'ediff-select-hook))))
@@ -2891,7 +2957,6 @@ Hit \\[ediff-recenter] to reset the windows afterward."
                    ediff-ancestor-buffer
                    (ediff-get-diff-overlay n 'Ancestor)))
               ))
-       (setq ediff-highlighting-style nil)
        
        ;; unhighlight fine diffs
        (ediff-set-fine-diff-properties ediff-current-difference 'default)
@@ -2920,8 +2985,97 @@ Hit \\[ediff-recenter] to reset the windows afterward."
          (setq ediff-current-difference n)
          ) ; end protected section
       
-      (ediff-with-current-buffer control-buf (ediff-refresh-mode-lines))
-      )))
+      (ediff-with-current-buffer control-buf (ediff-refresh-mode-lines)))
+    ))
+
+
+
+(defun ediff-highlight-diff-in-one-buffer (n buf-type)
+  (if (ediff-buffer-live-p (ediff-get-buffer buf-type))
+      (let* ((buff (ediff-get-buffer buf-type))
+            (last (ediff-with-current-buffer buff (point-max)))
+            (begin (ediff-get-diff-posn buf-type 'beg n))
+            (end (ediff-get-diff-posn buf-type 'end n))
+            (xtra (if (equal begin end) 1 0))
+            (end-hilit (min last (+ end xtra)))
+            (current-diff-overlay
+             (symbol-value
+              (ediff-get-symbol-from-alist
+               buf-type ediff-current-diff-overlay-alist))))
+
+       (if ediff-xemacs-p
+           (ediff-move-overlay current-diff-overlay begin end-hilit)
+         (ediff-move-overlay current-diff-overlay begin end-hilit buff))
+       (ediff-overlay-put current-diff-overlay 'priority
+                          (ediff-highest-priority begin end-hilit buff))
+       (ediff-overlay-put current-diff-overlay 'ediff-diff-num n)
+
+       ;; unhighlight the background overlay for diff n so it won't
+       ;; interfere with the current diff overlay
+       (ediff-set-overlay-face (ediff-get-diff-overlay n buf-type) nil)
+       )))
+
+
+(defun ediff-unhighlight-diff-in-one-buffer (buf-type)
+  (if (ediff-buffer-live-p (ediff-get-buffer buf-type))
+      (let ((current-diff-overlay
+            (symbol-value
+             (ediff-get-symbol-from-alist
+              buf-type ediff-current-diff-overlay-alist)))
+           (overlay
+            (ediff-get-diff-overlay ediff-current-difference buf-type))
+           )
+
+       (ediff-move-overlay current-diff-overlay 1 1)
+
+       ;; rehighlight the overlay in the background of the
+       ;; current difference region
+       (ediff-set-overlay-face
+        overlay
+        (if (and (ediff-has-face-support-p)
+                 ediff-use-faces ediff-highlight-all-diffs)
+            (ediff-background-face buf-type ediff-current-difference)))
+       )))
+
+(defun ediff-unhighlight-diffs-totally-in-one-buffer (buf-type)
+  (ediff-unselect-and-select-difference -1)
+  (if (and (ediff-has-face-support-p) ediff-use-faces)
+      (let* ((inhibit-quit t)
+            (current-diff-overlay-var
+             (ediff-get-symbol-from-alist
+              buf-type ediff-current-diff-overlay-alist))
+            (current-diff-overlay (symbol-value current-diff-overlay-var)))
+       (ediff-paint-background-regions 'unhighlight)
+       (if (ediff-overlayp current-diff-overlay)
+           (ediff-delete-overlay current-diff-overlay))
+       (set current-diff-overlay-var nil)
+       )))
+
+
+(defsubst ediff-highlight-diff (n)
+  "Put face on diff N.  Invoked for X displays only."
+  (ediff-highlight-diff-in-one-buffer n 'A)
+  (ediff-highlight-diff-in-one-buffer n 'B)
+  (ediff-highlight-diff-in-one-buffer n 'C)
+  (ediff-highlight-diff-in-one-buffer n 'Ancestor)
+  )
+
+
+(defsubst ediff-unhighlight-diff ()
+  "Remove overlays from buffers A, B, and C."
+  (ediff-unhighlight-diff-in-one-buffer 'A)
+  (ediff-unhighlight-diff-in-one-buffer 'B)
+  (ediff-unhighlight-diff-in-one-buffer 'C)
+  (ediff-unhighlight-diff-in-one-buffer 'Ancestor)
+  )
+
+;; delete highlighting overlays, restore faces to their original form
+(defsubst ediff-unhighlight-diffs-totally ()
+  (ediff-unhighlight-diffs-totally-in-one-buffer 'A)
+  (ediff-unhighlight-diffs-totally-in-one-buffer 'B)
+  (ediff-unhighlight-diffs-totally-in-one-buffer 'C)
+  (ediff-unhighlight-diffs-totally-in-one-buffer 'Ancestor)
+  )
 
 
 ;; This is adapted from a similar function in `emerge.el'.
@@ -2930,7 +3084,7 @@ Hit \\[ediff-recenter] to reset the windows afterward."
 ;; If DEFAULT-FILE is set, it should be used as the default value.
 ;; If DEFAULT-DIR is non-nil, use it as the default directory.
 ;; Otherwise, use the value of Emacs' variable `default-directory.'
-(defun ediff-read-file-name (prompt default-dir default-file)
+(defun ediff-read-file-name (prompt default-dir default-file &optional no-dirs)
   ;; hack default-dir if it is not set
   (setq default-dir
        (file-name-as-directory
@@ -2961,13 +3115,15 @@ Hit \\[ediff-recenter] to reset the windows afterward."
              )
             default-dir
             ))
-    ;; If user enters a directory name, expand the default file in that
+    ;; If user entered a directory name, expand the default file in that
     ;; directory.  This allows the user to enter a directory name for the
     ;; B-file and diff against the default-file in that directory instead
     ;; of a DIRED listing!
     (if (and (file-directory-p f) default-file)
        (setq f (expand-file-name
                 (file-name-nondirectory default-file) f)))
+    (if (and no-dirs (file-directory-p f))
+       (error "File %s is a directory" f))
     f)) 
   
 ;; If PREFIX is given, then it is used as a prefix for the temp file
@@ -3029,7 +3185,13 @@ Hit \\[ediff-recenter] to reset the windows afterward."
                (progn
                 (if (or (file-exists-p file) (not keep-proposed-name))
                     (setq file (make-temp-name proposed-name)))
-                (write-region "" nil file nil 'silent nil 'excl)
+                ;; the with-temp-buffer thing is a workaround for an XEmacs
+                ;; bug: write-region complains that we are trying to visit a
+                ;; file in an indirect buffer, failing to notice that the
+                ;; VISIT flag is unset and that we are actually writing from a
+                ;; string and not from any buffer.
+                (with-temp-buffer
+                  (write-region "" nil file nil 'silent nil 'excl))
                  nil)
             (file-already-exists t))
       ;; the file was somehow created by someone else between
@@ -3062,7 +3224,8 @@ Hit \\[ediff-recenter] to reset the windows afterward."
       (if (buffer-modified-p)
          ;; If buffer is not obsolete and is modified, offer to save
          (if (yes-or-no-p 
-              (format "Buffer out of sync with visited file.  Save file %s? "
+              (format "Buffer %s has been modified. Save it in file %s? "
+                      (buffer-name)
                       buffer-file-name))
              (condition-case nil
                  (save-buffer)
@@ -3074,7 +3237,9 @@ Hit \\[ediff-recenter] to reset the windows afterward."
        nil)
     ;; If buffer is obsolete, offer to revert
     (if (yes-or-no-p
-        (format "Buffer is out of sync with visited file.  REVERT file %s? "
+        (format "File %s was modified since visited by buffer %s.  REVERT file %s? "
+                buffer-file-name
+                (buffer-name)
                 buffer-file-name))
        (progn
          (if file-magic
@@ -3082,6 +3247,29 @@ Hit \\[ediff-recenter] to reset the windows afterward."
          (revert-buffer t t))
       (error "Buffer out of sync for file %s" buffer-file-name))))
 
+;; if there is another buffer visiting the file of the merge buffer, offer to
+;; save and delete the buffer; else bark
+(defun ediff-verify-file-merge-buffer (file)
+  (let ((buff (if (stringp file) (find-buffer-visiting file)))
+       warn-message)
+    (or (null buff)
+       (progn
+         (setq warn-message
+               (format "Buffer %s is visiting %s. Save and kill the buffer? "
+                       (buffer-name buff) file))
+         (with-output-to-temp-buffer ediff-msg-buffer
+           (princ "\n\n")
+           (princ warn-message)
+           (princ "\n\n"))
+         (if (y-or-n-p
+              (message warn-message))
+             (with-current-buffer buff
+               (save-buffer)
+               (kill-buffer (current-buffer)))
+           (error "Too dangerous to merge versions of a file visited by another buffer"))))
+    ))
+
+
 
 (defun ediff-filename-magic-p (file)
   (or (ediff-file-compressed-p file)
@@ -3116,6 +3304,78 @@ Without an argument, it saves customized diff argument, if available
            )
     (save-buffer)))
 
+
+;; idea suggested by Hannu Koivisto <azure@iki.fi>
+(defun ediff-clone-buffer-for-region-comparison (buff region-name)
+  (let ((cloned-buff (ediff-make-cloned-buffer buff region-name))
+       (wind (ediff-get-visible-buffer-window buff))
+       (pop-up-windows t)
+       other-wind
+       msg-buf)
+    (ediff-with-current-buffer cloned-buff
+      (setq ediff-temp-indirect-buffer t))
+    (if (window-live-p wind)
+       (set-window-buffer wind cloned-buff))
+    (pop-to-buffer cloned-buff)
+    (with-temp-buffer
+      (erase-buffer)
+      (insert
+       (format "\n   *******  Mark a region in buffer %s  *******\n"
+              (buffer-name cloned-buff)))
+      (insert
+       (format "\n\t      When done, type %s       Use %s to abort\n    "
+              (ediff-format-bindings-of 'exit-recursive-edit)
+              (ediff-format-bindings-of 'abort-recursive-edit)))
+      (goto-char (point-min))
+      (setq msg-buf (current-buffer))
+      (other-window 1)
+      (set-window-buffer (selected-window) msg-buf)
+      (shrink-window-if-larger-than-buffer)
+      (if (window-live-p wind)
+         (select-window wind))
+      (condition-case nil
+         (recursive-edit)
+       (quit
+        (ediff-kill-buffer-carefully cloned-buff)))
+      )
+    cloned-buff))
+
+
+(defun ediff-clone-buffer-for-window-comparison (buff wind region-name)
+  (let ((cloned-buff (ediff-make-cloned-buffer buff region-name)))
+    (ediff-with-current-buffer cloned-buff
+      (setq ediff-temp-indirect-buffer t))
+    (set-window-buffer wind cloned-buff)
+    cloned-buff))
+
+(defun ediff-clone-buffer-for-current-diff-comparison (buff buf-type reg-name)
+  (let ((cloned-buff (ediff-make-cloned-buffer buff reg-name))
+       (reg-start (ediff-get-diff-posn buf-type 'beg))
+       (reg-end (ediff-get-diff-posn buf-type 'end)))
+    (ediff-with-current-buffer cloned-buff
+      ;; set region to be the current diff region
+      (goto-char reg-start)
+      (set-mark reg-end)
+      (setq ediff-temp-indirect-buffer t))
+    cloned-buff))
+  
+
+
+(defun ediff-make-cloned-buffer (buff region-name)
+  (ediff-make-indirect-buffer
+   buff (concat
+        (if (stringp buff) buff (buffer-name buff))
+        region-name (symbol-name (gensym)))))
+
+
+(defun ediff-make-indirect-buffer (base-buf indirect-buf-name)
+  (ediff-cond-compile-for-xemacs-or-emacs
+   (make-indirect-buffer base-buf indirect-buf-name) ; xemacs
+   (make-indirect-buffer base-buf indirect-buf-name 'clone) ; emacs
+   ))
+
+
+;; This function operates only from an ediff control buffer
 (defun ediff-compute-custom-diffs-maybe ()
   (let ((buf-A-file-name (buffer-file-name ediff-buffer-A))
        (buf-B-file-name (buffer-file-name ediff-buffer-B))
@@ -3131,6 +3391,9 @@ Without an argument, it saves customized diff argument, if available
        (setq ediff-custom-diff-buffer
              (get-buffer-create
               (ediff-unique-buffer-name "*ediff-custom-diff" "*"))))
+    (ediff-with-current-buffer ediff-custom-diff-buffer
+      (setq buffer-read-only nil)
+      (erase-buffer))
     (ediff-exec-process
      ediff-custom-diff-program ediff-custom-diff-buffer 'synchronize
      ediff-custom-diff-options file-A file-B)
@@ -3183,10 +3446,18 @@ Ediff Control Panel to restore highlighting."
        (zmacs-regions t)
        (ctl-buf (current-buffer))
        quit-now
+       use-current-diff-p
        begA begB endA endB bufA bufB)
 
+    (if (ediff-valid-difference-p ediff-current-difference)
+       (progn
+         (ediff-set-fine-diff-properties ediff-current-difference 'default)
+         (ediff-unhighlight-diff)))
+    (ediff-paint-background-regions 'unhighlight)
+
     (cond ((ediff-merge-job)
           (setq bufB ediff-buffer-C)
+          ;; ask which buffer to compare to the merge buffer
           (while (cond ((eq answer ?A)
                         (setq bufA ediff-buffer-A
                               possibilities '(?B))
@@ -3201,10 +3472,12 @@ Ediff Control Panel to restore highlighting."
                           (sit-for 2)
                           t))
             (let ((cursor-in-echo-area t))
-              (message "Which buffer to compare to the merge buffer (A/B)? ")
+              (message
+               "Which buffer to compare to the merge buffer (A or B)? ")
               (setq answer (capitalize (read-char-exclusive))))))
 
          ((ediff-3way-comparison-job)
+          ;; ask which two buffers to compare
           (while (cond ((memq answer possibilities)
                         (setq possibilities (delq answer possibilities))
                         (setq bufA
@@ -3221,7 +3494,7 @@ Ediff Control Panel to restore highlighting."
                           t))
             (let ((cursor-in-echo-area t))
               (message "Enter the 1st buffer you want to compare (%s): "
-                       (mapconcat 'char-to-string possibilities "/"))
+                       (mapconcat 'char-to-string possibilities " or "))
               (setq answer (capitalize (read-char-exclusive)))))
           (setq answer "") ; silence error msg
           (while (cond ((memq answer possibilities)
@@ -3247,9 +3520,15 @@ Ediff Control Panel to restore highlighting."
                 bufB ediff-buffer-B
                 possibilities nil)))
 
+    (if (and (ediff-valid-difference-p ediff-current-difference)
+            (y-or-n-p "Compare currently highlighted difference regions? "))
+       (setq use-current-diff-p t))
+
+    (setq bufA (if use-current-diff-p
+                  (ediff-clone-buffer-for-current-diff-comparison
+                   bufA 'A "-Region.A-")
+                (ediff-clone-buffer-for-region-comparison bufA "-Region.A-")))
     (ediff-with-current-buffer bufA
-      (or (mark t)
-         (error "You forgot to specify a region in buffer %s" (buffer-name)))
       (setq begA (region-beginning)
            endA (region-end))
       (goto-char begA)
@@ -3259,9 +3538,12 @@ Ediff Control Panel to restore highlighting."
       (end-of-line)
       (or (eobp) (forward-char)) ; include the newline char
       (setq endA (point)))
+
+    (setq bufB (if use-current-diff-p
+                  (ediff-clone-buffer-for-current-diff-comparison
+                   bufB 'B "-Region.B-")
+                (ediff-clone-buffer-for-region-comparison bufB "-Region.B-")))
     (ediff-with-current-buffer bufB
-      (or (mark t)
-         (error "You forgot to specify a region in buffer %s" (buffer-name)))
       (setq begB (region-beginning)
            endB (region-end))
       (goto-char begB)
@@ -3272,57 +3554,15 @@ Ediff Control Panel to restore highlighting."
       (or (eobp) (forward-char)) ; include the newline char
       (setq endB (point)))
 
-    (ediff-unselect-and-select-difference
-     ediff-current-difference 'unselect-only)
-    (ediff-paint-background-regions 'unhighlight)
-
-    (ediff-with-current-buffer bufA
-      (goto-char begA)
-      (set-mark endA)
-      (narrow-to-region begA endA)
-      ;; (ediff-activate-mark)
-      )
-    ;; (sit-for 0)
-    (ediff-with-current-buffer bufB
-      (goto-char begB)
-      (set-mark endB)
-      (narrow-to-region begB endB)
-      ;; (ediff-activate-mark)
-      )
-    ;; (sit-for 0)
-    
-    ;; At this point, possibilities contains either the window char A/B/C
-    ;; that was not selected, or it is nil.  We delete the window that is not
-    ;; selected.
-    (if possibilities
-       (ediff-with-current-buffer ctl-buf
-         (let* ((wind-to-delete (eval
-                                 (ediff-get-symbol-from-alist
-                                  (car possibilities)
-                                   ediff-window-alist)))
-                (frame (window-frame wind-to-delete)))
-           (delete-window wind-to-delete)
-           (select-frame frame)
-           (balance-windows))))
-    (or (y-or-n-p 
-        "Please check regions selected for comparison.  Continue? ")
-       (setq quit-now t))
-    
-    (ediff-with-current-buffer bufA
-      (widen))
-    (ediff-with-current-buffer bufB
-      (widen))
-    (if quit-now
-       (ediff-with-current-buffer ctl-buf
-         (ediff-recenter)
-         (sit-for 0)
-         (error "All right.  Make up your mind and come back...")))
 
     (ediff-regions-internal
      bufA begA endA bufB begB endB
-     nil                       ; setup-hook
-     'ediff-regions-linewise   ; job name
-     nil                       ; no word mode
+     nil                       ; setup-hook
+     (if use-current-diff-p    ; job name
+        'ediff-regions-wordwise
+       'ediff-regions-linewise)
+     (if use-current-diff-p    ; word mode, if diffing current diff
+        t nil)
      ;; setup param to pass to ediff-setup
      (list (cons 'ediff-split-window-function ediff-split-window-function)))
     ))
@@ -3385,6 +3625,40 @@ Ediff Control Panel to restore highlighting."
       (ediff-overlay-put curr-overl 'after-string flag))
     ))
 
+
+;;; Some diff region tests
+
+;; t if diff region is empty.
+;; In case of buffer C, t also if it is not a 3way
+;; comparison job (merging jobs return t as well).
+(defun ediff-empty-diff-region-p (n buf-type)
+  (if (eq buf-type 'C)
+      (or (not ediff-3way-comparison-job)
+         (= (ediff-get-diff-posn 'C 'beg n)
+            (ediff-get-diff-posn 'C 'end n)))
+    (= (ediff-get-diff-posn buf-type 'beg n)
+       (ediff-get-diff-posn buf-type 'end n))))
+
+;; Test if diff region is white space only.
+;; If 2-way job and buf-type = C, then returns t.
+(defun ediff-whitespace-diff-region-p (n buf-type)
+  (or (and (eq buf-type 'C) (not ediff-3way-job))
+      (ediff-empty-diff-region-p n buf-type)
+      (let ((beg (ediff-get-diff-posn buf-type 'beg n))
+           (end (ediff-get-diff-posn buf-type 'end n)))
+       (ediff-with-current-buffer (ediff-get-buffer buf-type)
+         (save-excursion
+           (goto-char beg)
+           (skip-chars-forward ediff-whitespace)
+           (>= (point) end))))))
+
+
+(defsubst ediff-get-region-contents (n buf-type ctrl-buf &optional start end)
+  (ediff-with-current-buffer
+      (ediff-with-current-buffer ctrl-buf (ediff-get-buffer buf-type))
+    (buffer-substring
+     (or start (ediff-get-diff-posn buf-type 'beg n ctrl-buf))
+     (or end (ediff-get-diff-posn buf-type 'end n ctrl-buf)))))
   
 ;; Returns positions of difference sectors in the BUF-TYPE buffer.
 ;; BUF-TYPE should be a symbol -- `A', `B', or `C'. 
@@ -3465,10 +3739,11 @@ Ediff Control Panel to restore highlighting."
          (or (number-or-marker-p end)
              (setq end (eval end)))
          (setq overl 
-               (if ediff-xemacs-p
-                   (make-extent beg end buff)
-                 ;; advance front and rear of the overlay
-                 (make-overlay beg end buff nil 'rear-advance)))
+               (ediff-cond-compile-for-xemacs-or-emacs
+                (make-extent beg end buff)                     ; xemacs
+                ;; advance front and rear of the overlay
+                (make-overlay beg end buff nil 'rear-advance)  ; emacs
+                ))
          
          ;; never detach
          (ediff-overlay-put
@@ -3481,6 +3756,22 @@ Ediff Control Panel to restore highlighting."
                (ediff-overlay-put overl 'end-open nil)))
          (ediff-overlay-put overl 'ediff-diff-num 0)
          overl))))
+
+
+(defun ediff-make-current-diff-overlay (type)
+  (if (ediff-has-face-support-p)
+      (let ((overlay (ediff-get-symbol-from-alist
+                     type ediff-current-diff-overlay-alist))
+           (buffer (ediff-get-buffer type))
+           (face (face-name
+                  (symbol-value
+                   (ediff-get-symbol-from-alist
+                    type ediff-current-diff-face-alist)))))
+       (set overlay
+            (ediff-make-bullet-proof-overlay (point-max) (point-max) buffer))
+       (ediff-set-overlay-face (symbol-value overlay) face)
+       (ediff-overlay-put (symbol-value overlay) 'ediff ediff-control-buffer))
+    ))
          
   
 ;; Like other-buffer, but prefers visible buffers and ignores temporary or
@@ -3693,7 +3984,7 @@ Mail anyway? (y or n) ")
              (set-buffer ctl-buf))
          (setq buffer-name (buffer-name))
          (require 'reporter)
-         (reporter-submit-bug-report "kifer@cs.sunysb.edu"
+         (reporter-submit-bug-report "kifer@cs.stonybrook.edu"
                                      (ediff-version)
                                      varlist
                                      nil 
@@ -3727,13 +4018,15 @@ Mail anyway? (y or n) ")
 
        
 (defun ediff-deactivate-mark ()
-  (if ediff-xemacs-p
-         (zmacs-deactivate-region)
-       (deactivate-mark)))
+  (ediff-cond-compile-for-xemacs-or-emacs
+   (zmacs-deactivate-region) ; xemacs
+   (deactivate-mark) ; emacs
+   ))
 (defun ediff-activate-mark ()
-  (if ediff-emacs-p
-      (setq mark-active t)
-    (zmacs-activate-region)))
+  (ediff-cond-compile-for-xemacs-or-emacs
+   (zmacs-activate-region) ; xemacs
+   (setq mark-active t) ; emacs
+   ))
 
 (cond ((fboundp 'nuke-selective-display)
        ;; XEmacs 19.12 has nuke-selective-display
@@ -3845,7 +4138,12 @@ Mail anyway? (y or n) ")
   "Toggle profiling Ediff commands."
   (interactive)
   (ediff-barf-if-not-control-buffer)
-  (make-local-hook 'post-command-hook)
+
+  (ediff-cond-compile-for-xemacs-or-emacs
+   (make-local-hook 'post-command-hook) ; xemacs form
+   nil                                  ; emacs form
+   )
+
   (let ((pre-hook 'pre-command-hook)
        (post-hook 'post-command-hook))
     (if (not (equal ediff-command-begin-time '(0 0 0)))
@@ -3853,8 +4151,8 @@ Mail anyway? (y or n) ")
               (remove-hook post-hook 'ediff-calc-command-time)
               (setq ediff-command-begin-time '(0 0 0))
               (message "Ediff profiling disabled"))
-      (add-hook pre-hook 'ediff-save-time t t)
-      (add-hook post-hook 'ediff-calc-command-time nil t)
+      (add-hook pre-hook 'ediff-save-time t 'local)
+      (add-hook post-hook 'ediff-calc-command-time nil 'local)
       (message "Ediff profiling enabled"))))
     
 (defun ediff-print-diff-vector (diff-vector-var)
@@ -3905,6 +4203,16 @@ Mail anyway? (y or n) ")
     (setq lis (cdr lis)))
   lis)
 
+;; Make a readable representation of the invocation sequence for FUNC-DEF.
+;; It would either be a key or M-x something.
+(defun ediff-format-bindings-of (func-def)
+  (let ((desc (car (where-is-internal func-def
+                                     overriding-local-map
+                                     nil nil))))
+    (if desc
+       (key-description desc)
+      (format "M-x %s" func-def))))
+
 ;; this uses comparison-func to decide who is a member, and this determines how
 ;; intersection looks like
 (defun ediff-intersection (lis1 lis2 comparison-func)
@@ -3940,7 +4248,7 @@ Mail anyway? (y or n) ")
     (cdr result)))
 
 (if (fboundp 'copy-sequence)
-    (defalias 'ediff-copy-list 'copy-sequence)
+    (fset 'ediff-copy-list (symbol-function 'copy-sequence))
   (defun ediff-copy-list (list)
     (if (consp list)
       ;;;(let ((res nil))