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diff --git a/lisp/ediff-hook.el b/lisp/ediff-hook.el
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+;;; ediff-hook.el --- setup for Ediff's menus and autoloads
+;;; Copyright (C) 1995 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+;;;   These must be placed in menu-bar.el in Emacs
+;;
+;;      (define-key menu-bar-tools-menu [eregistry]
+;;      '("List Ediff Sessions" . ediff-show-registry))
+;;      (define-key menu-bar-tools-menu [epatch]
+;;      '("Apply Patch" . menu-bar-epatch-menu))
+;;      (define-key menu-bar-tools-menu [ediff-merge]
+;;      '("Merge" . menu-bar-ediff-merge-menu))
+;;      (define-key menu-bar-tools-menu [ediff]
+;;      '("Compare" . menu-bar-ediff-menu))
+
+
+(defun ediff-xemacs-init-menus ()
+  (if (featurep 'menubar)
+      (progn
+        (add-submenu
+         '("Tools") ediff-menu "OO-Browser...")
+        (add-submenu
+         '("Tools") ediff-merge-menu "OO-Browser...")
+        (add-submenu
+         '("Tools") epatch-menu "OO-Browser...")
+        (add-menu-button
+         '("Tools")
+         ["List Ediff Sessions" ediff-show-registry t] "OO-Browser...")
+        (add-menu-button
+         '("Tools")
+         ["---" nil nil] "OO-Browser...")
+        )))
+
+
+
+;; explicit string-match is needed: ediff-xemacs-p is not defined at build time
+(cond ((string-match "XEmacs" emacs-version)
+       (defvar ediff-menu
+         '("Compare"
+           ["Two Files ..."  ediff-files t]
+           ["Two Buffers ..." ediff-buffers t]
+           ["Three Files ..."  ediff-files3 t]
+           ["Three Buffers ..." ediff-buffers3 t]
+           "---"
+           ["Two Directories ..." ediff-directories t]
+           ["Three Directories ..." ediff-directories3 t]
+           "---"
+           ["File with Revision ..."  ediff-revision t]
+           ["Directory Revisions ..."  ediff-directory-revisions t]
+           "---"
+           ["Windows Word-by-word ..." ediff-windows-wordwise t]
+           ["Windows Line-by-line ..." ediff-windows-linewise t]
+           "---"
+           ["Regions Word-by-word ..." ediff-regions-wordwise t]
+           ["Regions Line-by-line ..." ediff-regions-linewise t]))
+       (defvar ediff-merge-menu
+         '("Merge"
+           ["Files ..."  ediff-merge-files t]
+           ["Files with Ancestor ..." ediff-merge-files-with-ancestor t]
+           ["Buffers ..."  ediff-merge-buffers t]
+           ["Buffers with Ancestor ..."
+            ediff-merge-buffers-with-ancestor t]
+           "---"
+           ["Directories ..."  ediff-merge-directories t]
+           ["Directories with Ancestor ..."
+            ediff-merge-directories-with-ancestor t]
+           "---"
+           ["Revisions ..."  ediff-merge-revisions t]
+           ["Revisions with Ancestor ..."
+            ediff-merge-revisions-with-ancestor t]
+           ["Directory Revisions ..." ediff-merge-directory-revisions t]
+           ["Directory Revisions with Ancestor ..."
+            ediff-merge-directory-revisions-with-ancestor t]))
+       (defvar epatch-menu
+         '("Apply Patch"
+           ["To a file ..."  ediff-patch-file t]
+           ["To a buffer ..." ediff-patch-buffer t]))
+
+       ;; put these menus before Object-Oriented-Browser in Tools menu
+       (add-hook 'before-init-hook 'ediff-xemacs-init-menus)
+       ;; this `if' is to be deleted before going into distribution
+       (if (not purify-flag)
+           (ediff-xemacs-init-menus))
+       )
+      
+      ;; Emacs--only if menu-bar is loaded
+      ((featurep 'menu-bar)
+       ;; initialize menu bar keymaps
+       (defvar menu-bar-epatch-menu (make-sparse-keymap))
+       (fset 'menu-bar-epatch-menu (symbol-value 'menu-bar-epatch-menu))
+       (defvar menu-bar-ediff-merge-menu (make-sparse-keymap))
+       (fset 'menu-bar-ediff-merge-menu 
+             (symbol-value 'menu-bar-ediff-merge-menu))
+       (defvar menu-bar-ediff-menu (make-sparse-keymap))
+       (fset 'menu-bar-ediff-menu (symbol-value 'menu-bar-ediff-menu))
+
+       ;; define ediff-menu
+       (define-key menu-bar-ediff-menu [ediff-dir-revision]
+         '("Directory Revisions ..." . ediff-directory-revisions))
+       (define-key menu-bar-ediff-menu [ediff-revision]
+         '("File with Revision ..." . ediff-revision))
+       (define-key menu-bar-ediff-menu [separator-ediff-directories] '("--"))
+       (define-key menu-bar-ediff-menu [ediff-directories3]
+         '("Three Directories ..." . ediff-directories3))
+       (define-key menu-bar-ediff-menu [ediff-directories]
+         '("Two Directories ..." . ediff-directories))
+       (define-key menu-bar-ediff-menu [separator-ediff-files] '("--"))
+       (define-key menu-bar-ediff-menu [ediff-buffers3]
+         '("Three Buffers ..." . ediff-buffers3))
+       (define-key menu-bar-ediff-menu [ediff-files3]
+         '("Three Files ..." . ediff-files3))
+       (define-key menu-bar-ediff-menu [ediff-buffers]
+         '("Two Buffers ..." . ediff-buffers))
+       (define-key menu-bar-ediff-menu [ediff-files]
+         '("Two Files ..." . ediff-files))
+       (define-key menu-bar-ediff-menu [separator-ediff-regions] '("--"))
+       (define-key menu-bar-ediff-menu [ediff-regions-linewise]
+         '("Regions Line-by-line ..." . ediff-regions-linewise))
+       (define-key menu-bar-ediff-menu [ediff-regions-wordwise]
+         '("Regions Word-by-word ..." . ediff-regions-wordwise))
+       (define-key menu-bar-ediff-menu [separator-ediff-windows] '("--"))
+       (define-key menu-bar-ediff-menu [ediff-windows-linewise]
+         '("Windows Line-by-line ..." . ediff-windows-linewise))
+       (define-key menu-bar-ediff-menu [ediff-windows-wordwise]
+         '("Windows Word-by-word ..." . ediff-windows-wordwise))
+
+       ;; define merge menu
+       (define-key
+         menu-bar-ediff-merge-menu [ediff-merge-dir-revisions-with-ancestor]
+         '("Directory Revisions with Ancestor ..."
+           . ediff-merge-directory-revisions-with-ancestor))
+       (define-key
+         menu-bar-ediff-merge-menu [ediff-merge-dir-revisions]
+         '("Directory Revisions ..." . ediff-merge-directory-revisions))
+       (define-key
+         menu-bar-ediff-merge-menu [ediff-merge-revisions-with-ancestor]
+         '("Revisions with Ancestor ..."
+           . ediff-merge-revisions-with-ancestor))
+       (define-key menu-bar-ediff-merge-menu [ediff-merge-revisions]
+         '("Revisions ..." . ediff-merge-revisions))
+       (define-key menu-bar-ediff-merge-menu [separator-ediff-merge] '("--"))
+       (define-key
+         menu-bar-ediff-merge-menu [ediff-merge-directories-with-ancestor]
+         '("Directories with Ancestor ..."
+           . ediff-merge-directories-with-ancestor))
+       (define-key menu-bar-ediff-merge-menu [ediff-merge-directories]
+         '("Directories ..." . ediff-merge-directories))
+       (define-key 
+         menu-bar-ediff-merge-menu [separator-ediff-merge-dirs] '("--"))
+       (define-key
+         menu-bar-ediff-merge-menu [ediff-merge-buffers-with-ancestor]
+         '("Buffers with Ancestor ..." . ediff-merge-buffers-with-ancestor))
+       (define-key menu-bar-ediff-merge-menu [ediff-merge-buffers]
+         '("Buffers ..." . ediff-merge-buffers))
+       (define-key menu-bar-ediff-merge-menu [ediff-merge-files-with-ancestor]
+         '("Files with Ancestor ..." . ediff-merge-files-with-ancestor))
+       (define-key menu-bar-ediff-merge-menu [ediff-merge-files]
+         '("Files ..." . ediff-merge-files))
+
+       ;; define epatch menu
+       (define-key menu-bar-epatch-menu [ediff-patch-buffer]
+         '("To a Buffer ..." . ediff-patch-buffer))
+       (define-key menu-bar-epatch-menu [ediff-patch-file]
+         '("To a File ..." . ediff-patch-file)))
+      
+      ) ; cond
+
+;; arrange foe autoloads
+(if purify-flag
+    () ; if dumping, autoloads are set up in loaddefs.el
+  ;; if the user decides to load this file, set up autoloads
+  ;; compare files and buffers
+  (autoload 'ediff "ediff" "Compare two files" t)
+  (autoload 'ediff-files "ediff" "Compare two files" t)
+  (autoload 'ediff-buffers "ediff" "Compare two bufers" t)
+  (autoload 'ediff3  "ediff"  "Compare three files" t)
+  (autoload 'ediff-files3 "ediff" "Compare three files" t)
+  (autoload 'ediff-buffers3 "ediff" "Compare three bufers" t)
+
+  (autoload 'ediff-revision "ediff" "Compare versions of a file" t)
+
+  ;; compare regions and windows
+  (autoload 'ediff-windows-wordwise 
+    "ediff" "Compare two windows word-by-word" t)
+  (autoload 'ediff-regions-wordwise 
+    "ediff" "Compare two regions word-by-word" t)
+  (autoload 'ediff-windows-linewise 
+    "ediff" "Compare two windows line-by-line" t)
+  (autoload 'ediff-regions-linewise 
+    "ediff" "Compare two regions line-by-line" t)
+
+  ;; patch
+  (autoload 'ediff-patch-file "ediff" "Patch a file" t)
+  (autoload 'epatch "ediff" "Patch a file" t)
+  (autoload 'ediff-patch-buffer "ediff" "Patch a buffer")
+  (autoload 'epatch-buffer "ediff" "Patch a buffer" t)
+
+  ;; merge
+  (autoload 'ediff-merge "ediff" "Merge two files" t)
+  (autoload 'ediff-merge-files "ediff" "Merge two files" t)
+  (autoload 'ediff-merge-files-with-ancestor
+    "ediff" "Merge two files using a third file as an ancestor" t)
+  (autoload 'ediff-merge-buffers "ediff" "Merge two buffers" t)
+  (autoload 'ediff-merge-buffers-with-ancestor
+    "ediff" "Merge two buffers using a third buffer as an ancestor" t)
+
+  (autoload 'ediff-merge-revisions "ediff" "Merge two versions of a file" t)
+  (autoload 'ediff-merge-revisions-with-ancestor
+    "ediff" "Merge two versions of a file" t)
+
+  ;; compare directories
+  (autoload 'edirs "ediff" "Compare files in two directories" t)
+  (autoload 'ediff-directories "ediff" "Compare files in two directories" t)
+  (autoload 'edirs3 "ediff" "Compare files in three directories" t)
+  (autoload 'ediff-directories3 "ediff" "Compare files in three directories" t)
+
+  (autoload 'edir-revisions 
+    "ediff" "Compare two versions of a file" t)
+  (autoload 'ediff-directory-revisions 
+    "ediff" "Compare two versions of a file" t)
+
+  ;; merge directories
+  (autoload 'edirs-merge "ediff" "Merge files in two directories" t)
+  (autoload 'ediff-merge-directories
+    "ediff" "Merge files in two directories" t)
+  (autoload 'edirs-merge-with-ancestor
+    "ediff"
+    "Merge files in two directories using files in a third dir as ancestors" t)
+  (autoload 'ediff-merge-directories-with-ancestor
+    "ediff"
+    "Merge files in two directories using files in a third dir as ancestors" t)
+
+  (autoload 'edir-merge-revisions 
+    "ediff" "Merge versions of files in a directory" t)
+  (autoload 'ediff-merge-directory-revisions 
+    "ediff" "Merge versions of files in a directory" t)
+  (autoload 'ediff-merge-directory-revisions-with-ancestor
+    "ediff"
+    "Merge versions of files in a directory using other versions as ancestors"
+    t)
+  (autoload 'edir-merge-revisions-with-ancestor
+    "ediff"
+    "Merge versions of files in a directory using other versions as ancestors"
+    t)
+  (autoload 'ediff-show-registry
+    "ediff-meta"
+    "Display the registry of active Ediff sessions"
+    t)
+  ) ; if purify-flag
+
+
+(provide 'ediff-hook)
+
+
+;;; ediff-hook.el ends here
diff --git a/lisp/ediff-mult.el b/lisp/ediff-mult.el
new file mode 100644
index 00000000000..e50e51e5617
--- /dev/null
+++ b/lisp/ediff-mult.el
@@ -0,0 +1,1415 @@
+;;; ediff-meta.el --- support for multi-file/multi-buffer processing in Ediff
+;;; Copyright (C) 1995 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+;;; Notes:
+;;
+;; Users are strongly encourage to add functionality to this file.
+;; In particular, epatch needs to be enhanced to work with multi-file
+;; patches. The present file contains all the infrastructure needed for that.
+;;
+;; Generally, to to implement a new multisession capability within Ediff,
+;; you need to tell it 
+;;
+;;      1. How to display the session group buffer.
+;;         This function must indicate which Ediff sessions are active (+) and
+;;         which are finished (-).
+;;         See ediff-redraw-directory-group-buffer for an example.
+;;         In all likelihood, ediff-redraw-directory-group-buffer can be used
+;;         directly or after a small modification.
+;;      2. What action to take when the user clicks button 2 or types v,e, or
+;;         RET.  See ediff-dir-action.
+;;      3. Provide a list of pairs or triples of file names (or buffers,
+;;         depending on the particular Ediff operation you want to invoke)
+;;         in the following format:
+;;              ((obj1 obj2 [optional obj3]) (...) ...)
+;;         Actually, the format of this list is pretty much up to the
+;;         developer. The only thing is that it must be a list of lists.
+;;         Also, keep in mind that the function ediff-prepare-meta-buffer
+;;         (which see) prepends nil in fron of each list (i.e., the above list
+;;         will become ((nil obj1 obj2 ...) (nil ...) ...).
+;;         Ediff expects that your function (in 2 above) will arrange to
+;;         replace this prepended nil (via setcar) with the actual ediff
+;;         control buffer associated with an appropriate Ediff session.
+;;         This is arranged through internal startup hooks that can be passed
+;;         to any of Ediff major entries (such as ediff-files, epatch, etc.).
+;;         See how this is done in ediff-dir-action.
+;;      4. Write a function that makes a call to ediff-prepare-meta-buffer
+;;         passing all this info. 
+;;         You may be able to use ediff-directories-internal as a template.
+;;      5. If you intend to add several related pieces of functionality,
+;;         you may want to keep the function in 4 as an internal version
+;;         and then write several top-level interactive functions that call it
+;;         with different parameters.
+;;         See how ediff-directories, ediff-merge-directories, and
+;;         ediff-merge-directories-with-ancestor all use
+;;         ediff-directories-internal. 
+;;
+;; In case of multifile patching, the easiest thing is to first apply the patch
+;; and then find out which files were patched (using the algorithm utilized by
+;; Unix patch and by parsing the patch file). The procedure ediff-patch-file
+;; works for single-file patches only. However, it can deal with remote and
+;; compressed files. Check out ediff-patch-file for details.
+;;
+;; Another useful addition here could be session groups selected by patterns
+;; (which are different in each directory). For instance, one may want to
+;; compare files of the form abc{something}.c to files old{something}.d
+;; which may be in the same or different directories. Or, one may want to
+;; compare all files of the form {something} to files of the form {something}~.
+;;
+;; Implementing this require writing an collating function, which would pair up
+;; appropriate files. It will also require a generalization of the functions
+;; that do the layout of the meta- and differences buffers and of
+;; ediff-dir-action.
+
+(require 'ediff-init)
+
+;; meta-buffer
+(ediff-defvar-local ediff-meta-buffer nil "")
+(ediff-defvar-local ediff-parent-meta-buffer nil "")
+;; the registry buffer
+(defvar ediff-registry-buffer nil)
+
+(defconst ediff-meta-buffer-message "This is an Ediff Session Group Panel: %s
+
+Useful commands:
+     button2, `v', RET over a session line:   start that Ediff session
+     `M' in any session invoked from here:    bring back this buffer
+     `R':\tdisplay the registry of active Ediff sessions
+     `h':\tmark session for hiding; with prefix arg--unmark
+     `x':\thide marked sessions; with prefix arg--unhide hidden sessions
+     `m':\tmark session for non-hiding operation; with prefix arg--unmark
+     SPC:\tnext session
+     DEL:\tprevious session
+     `E':\tbrowse Ediff on-line manual
+     `q':\tquit this session group
+")
+
+(ediff-defvar-local ediff-meta-buffer-map nil
+  "The keymap for the meta buffer.")
+(defvar ediff-dir-diffs-buffer-map (make-sparse-keymap)
+  "The keymap to be installed in the buffer showing differences between
+directories.")
+
+;; Variable specifying the action to take when the use invokes ediff in the
+;; meta buffer. This is usually ediff-registry-action or ediff-dir-action
+(ediff-defvar-local ediff-meta-action-function nil "")
+;; Tells ediff-update-meta-buffer how to redraw it
+(ediff-defvar-local ediff-meta-redraw-function nil "")
+;; Tells ediff-dir-action and similar procedures how to invoke Ediff for the
+;; sessions in a given session group
+(ediff-defvar-local ediff-session-action-function nil "")
+
+(ediff-defvar-local ediff-metajob-name nil "")
+
+;; buffer used to collect custom diffs from individual sessions in the group
+(ediff-defvar-local ediff-meta-diff-buffer nil "")
+
+;; history var to use for filtering groups
+(defvar ediff-filtering-regexp-history nil "")
+
+;; This has the form ((ctl-buf file1 file2) (stl-buf file1 file2) ...)
+;; If ctl-buf is nil, the file-pare wasn't processed yet. If it is
+;; killed-buffer object, the file pair has been processed. If it is a live
+;; buffer, this means ediff is still working on the pair
+(ediff-defvar-local ediff-meta-list nil "")
+
+
+;; the difference list between directories in a directory session group
+(ediff-defvar-local ediff-dir-difference-list nil "")
+(ediff-defvar-local ediff-dir-diffs-buffer nil "")
+
+;; The registry of Ediff sessions. A list of control buffers.
+(defvar ediff-session-registry nil)
+
+(defvar ediff-registry-setup-hook nil
+  "*Hooks run just after the registry control panel is set up.")
+(defvar ediff-session-group-setup-hook nil
+  "*Hooks run just after a meta-buffer controlling a session group, such as
+ediff-directories, is run.")
+(defvar ediff-show-registry-hook nil
+  "*Hooks run just after the registry buffer is shown.")
+(defvar ediff-show-session-group-hook nil
+  "*Hooks run just after a session group buffer is shown.")
+
+;;; API
+
+(defun ediff-get-group-buffer (meta-list)
+  (nth 0 (car meta-list)))
+(defun ediff-get-group-regexp (meta-list)
+  (nth 1 (car meta-list)))
+(defun ediff-get-group-objA (meta-list)
+  (nth 2 (car meta-list)))
+(defun ediff-get-group-objB (meta-list)
+  (nth 3 (car meta-list)))
+(defun ediff-get-group-objC (meta-list)
+  (nth 4 (car meta-list)))
+(defun ediff-get-session-buffer (elt)
+  (nth 0 elt))
+(defun ediff-get-session-status (elt)
+  (nth 1 elt))
+(defun ediff-get-session-objA (elt)
+  (nth 2 elt))
+(defun ediff-get-session-objB (elt)
+  (nth 3 elt))
+(defun ediff-get-session-objC (elt)
+  (nth 4 elt))
+(defun ediff-set-session-status (session-info new-status)
+  (setcar (cdr session-info) new-status))
+
+;; set up the keymap in the meta buffer
+(defun ediff-setup-meta-map()
+  (setq ediff-meta-buffer-map (make-sparse-keymap))
+  (suppress-keymap ediff-meta-buffer-map)
+  (define-key ediff-meta-buffer-map "q" 'ediff-quit-meta-buffer)
+  (define-key ediff-meta-buffer-map "R" 'ediff-show-registry)
+  (define-key ediff-meta-buffer-map "E" 'ediff-documentation)
+  (define-key ediff-meta-buffer-map "v" ediff-meta-action-function)
+  (define-key ediff-meta-buffer-map "\C-m" ediff-meta-action-function)
+  (define-key ediff-meta-buffer-map  " "  'ediff-next-meta-item)
+  (define-key ediff-meta-buffer-map  "\C-?"  'ediff-previous-meta-item)
+  (define-key ediff-meta-buffer-map  [delete]  'ediff-previous-meta-item)
+  (define-key ediff-meta-buffer-map  [backspace]  'ediff-previous-meta-item)
+  (if ediff-no-emacs-help-in-control-buffer
+      (define-key ediff-meta-buffer-map  "\C-h"  'ediff-previous-meta-item))
+  (if ediff-emacs-p
+      (define-key ediff-meta-buffer-map [mouse-2] ediff-meta-action-function)
+    (define-key ediff-meta-buffer-map [button2] ediff-meta-action-function))
+
+  (use-local-map ediff-meta-buffer-map))
+
+(defun ediff-meta-mode ()
+  "This mode controls all operations on Ediff session groups.
+It is entered through one of the following commands:
+        `ediff-directories'
+        `edirs'
+        `ediff-directories3'
+        `edirs3'
+        `ediff-merge-directories'
+        `edirs-merge'
+        `ediff-merge-directories-with-ancestor'
+        `edirs-merge-with-ancestor'
+        `ediff-directory-revisions'
+        `edir-revisions'
+        `ediff-merge-directory-revisions'
+        `edir-merge-revisions'
+        `ediff-merge-directory-revisions-with-ancestor'
+        `edir-merge-revisions-with-ancestor'
+
+Commands:
+\\{ediff-meta-buffer-map}"
+  (kill-all-local-variables)
+  (setq major-mode 'ediff-meta-mode)
+  (setq mode-name "MetaEdiff"))
+
+
+;; the keymap for the buffer showing directory differences
+(suppress-keymap ediff-dir-diffs-buffer-map)
+(define-key ediff-dir-diffs-buffer-map "q" 'ediff-bury-dir-diffs-buffer)
+(define-key ediff-dir-diffs-buffer-map " " 'next-line)
+(define-key ediff-dir-diffs-buffer-map "\C-?" 'previous-line)
+(define-key ediff-dir-diffs-buffer-map [delete] 'previous-line)
+(define-key ediff-dir-diffs-buffer-map [backspace] 'previous-line)
+
+(defun ediff-next-meta-item (count)
+  "Move to the next item in Ediff registry or session group buffer.
+Moves in circular fashion. With numeric prefix arg, skip this many items."
+  (interactive "p")
+  (or count (setq count 1))
+  (while (< 0 count)
+    (setq count (1- count))
+    (ediff-next-meta-item1)))
+
+;; Move to the next meta item
+(defun ediff-next-meta-item1 ()
+  (let (pos)
+    (setq pos (ediff-next-meta-overlay-start (point)))
+;;;     ;; skip deleted
+;;;    (while (memq (ediff-get-session-status
+;;;               (ediff-get-meta-info (current-buffer) pos 'noerror))
+;;;              '(?H ?I))
+;;;      (setq pos (ediff-next-meta-overlay-start pos)))
+    
+    (if pos (goto-char pos))
+    (if (eq ediff-metajob-name 'ediff-registry)
+        (if (search-forward "*Ediff" nil t)
+            (skip-chars-backward "a-zA-Z*"))
+      (if (> (skip-chars-forward "-+?H* \t0-9") 0)
+          (backward-char 1)))))
+
+
+(defun ediff-previous-meta-item (count)
+  "Move to the previous item in Ediff registry or session group buffer.
+Moves in circular fashion. With numeric prefix arg, skip this many items."
+  (interactive "p")
+  (or count (setq count 1))
+  (while (< 0 count)
+    (setq count (1- count))
+    (ediff-previous-meta-item1)))
+
+(defun ediff-previous-meta-item1 ()
+  (let (pos)
+    (setq pos (ediff-previous-meta-overlay-start (point)))
+;;;     ;; skip deleted
+;;;    (while (ediff-get-session-status
+;;;         (ediff-get-meta-info (current-buffer) pos 'noerror))
+;;;      (setq pos (ediff-previous-meta-overlay-start pos)))
+    
+    (if pos (goto-char pos))
+    (if (eq ediff-metajob-name 'ediff-registry)
+        (if (search-forward "*Ediff" nil t)
+            (skip-chars-backward "a-zA-Z*"))
+      (if (> (skip-chars-forward "-+?H* \t0-9") 0)
+          (backward-char 1)))))
+
+
+
+;; DIR1, DIR2, DIR3 are directories.
+;; REGEXP is a regexp used to filter
+;; files in the directories.
+;; If a file is a directory in dir1 but not dir2 (or vice versa), it is not
+;; included in the intersection. However, a regular file that is a dir in dir3
+;; is included, since dir3 files are supposed to be ancestors for merging.
+;; Returns a list of the form:
+;;      ((dir1 dir2 dir3) (f1 f2 f3) (f1 f2 f3) ...)
+;; dir3, f3 can be nil if intersecting only 2 directories.
+;; If COMPARISON-FUNC is given, use it. Otherwise, use string=
+;; DIFF-VAR is contains the name of the variable in which to return the
+;; difference list. The diff list is of the form:
+;;      ((dir1 dir2 dir3) (file . num) (file . num)...)
+;; where num encodes the set of dirs where the file is found:
+;; 2 - only dir1; 3 - only dir2; 5 - only dir3; 6 - dir1&2; 10 - dir1&3; etc.
+(defun ediff-intersect-directories (jobname diff-var regexp dir1 dir2
+                                            &optional dir3 comparison-func)
+  (require 'cl)
+  (setq comparison-func (or comparison-func 'string=))
+  (let (lis1 lis2 lis3 common auxdir1 auxdir2 auxdir3 difflist)
+
+    (setq auxdir1       (file-name-as-directory dir1)
+          lis1          (directory-files auxdir1 nil regexp)
+          auxdir2       (file-name-as-directory dir2)
+          lis2          (directory-files auxdir2 nil regexp))
+
+    (if (stringp dir3)
+        (setq auxdir3   (file-name-as-directory dir3)
+              lis3      (directory-files auxdir3 nil regexp)))
+
+    (setq lis1 (delete "."  lis1)
+          lis1 (delete ".." lis1))
+
+    (setq common (intersection lis1 lis2 :test comparison-func))
+    ;; get rid of files that are directories in dir1 but not dir2
+    (mapcar (function (lambda (elt)
+                        (if (Xor (file-directory-p (concat auxdir1 elt))
+                                 (file-directory-p (concat auxdir2 elt)))
+                            (setq common (delq elt common)))))
+            common)
+    ;; intersect with the third dir
+    (if lis3 (setq common (intersection common lis3 :test comparison-func)))
+    (if (ediff-comparison-metajob3 jobname)
+        (mapcar (function (lambda (elt)
+                            (if (Xor (file-directory-p (concat auxdir1 elt))
+                                     (file-directory-p (concat auxdir3 elt)))
+                                (setq common (delq elt common)))))
+                common))
+
+    ;; trying to avoid side effects of sorting
+    (setq common (sort (copy-list common) 'string-lessp))
+
+    ;; compute difference list
+    (setq difflist (set-difference
+                    (union (union lis1 lis2 :test comparison-func)
+                           lis3
+                           :test comparison-func)
+                    common
+                    :test comparison-func)
+          difflist (delete "."  difflist)
+          ;; copy-list needed because sort sorts it by side effects
+          difflist (sort (copy-list (delete ".." difflist)) 'string-lessp))
+
+    (setq difflist (mapcar (function (lambda (elt) (cons elt 1))) difflist))
+
+    ;; check for files belonging to lis1/2/3
+    (mapcar (function (lambda (elt) 
+                        (if (member (car elt) lis1)
+                            (setcdr elt (* (cdr elt) 2)))
+                        (if (member (car elt) lis2)
+                            (setcdr elt (* (cdr elt) 3)))
+                        (if (member (car elt) lis3)
+                            (setcdr elt (* (cdr elt) 5)))
+                        ))
+            difflist)
+    (setq difflist (cons (list regexp auxdir1 auxdir2 auxdir3) difflist))
+    
+    (set diff-var difflist)
+
+    ;; return result
+    (cons (list regexp auxdir1 auxdir2 auxdir3)
+          (mapcar (function (lambda (elt) 
+                              (list (concat auxdir1 elt)
+                                    (concat auxdir2 elt)
+                                    (if lis3
+                                        (concat auxdir3 elt)))))
+                  common))
+    ))
+
+;; find directory files that are under revision.
+;; display subdirectories, too, since we may visit them recursively.
+(defun ediff-get-directory-files-under-revision (jobname regexp dir1)
+  (require 'cl)
+  (let (lis1 elt common auxdir1)
+    (setq auxdir1 (file-name-as-directory dir1)
+          lis1    (directory-files auxdir1 nil regexp))
+
+    (while lis1
+      (setq elt  (car lis1)
+            lis1 (cdr lis1))
+      ;; take files under revision control
+      (cond ((file-directory-p (concat auxdir1 elt))
+             (setq common (cons elt common)))
+            ((file-exists-p (concat auxdir1 elt ",v"))
+             (setq common (cons elt common))))
+      ) ; while
+
+    (setq common (delete "."  common)
+          common (delete ".." common))
+
+    ;; trying to avoid side effects of sorting
+    (setq common (sort (copy-list common) 'string-lessp))
+
+    ;; return result
+    (cons (list regexp auxdir1 nil nil)
+          (mapcar (function (lambda (elt) 
+                              (list (concat auxdir1 elt)
+                                    nil nil)))
+                  common))
+    ))
+      
+
+;; If file groups selected by patterns will ever be implemented, this
+;; comparison function might become useful.
+;;;; uses external variables PAT1 PAT2 to compare str1/2
+;;;; patterns must be of the form ???*???? where ??? are strings of chars
+;;;; containing no *.
+;;(defun ediff-pattern= (str1 str2)
+;;  (let (pos11 pos12 pos21 pos22 len1 len2)
+;;    (setq pos11 0
+;;        len  (length epat1)
+;;        pos12 len)
+;;    (while (and (< pos11 len) (not (= (aref epat1 pos11) ?*)))
+;;      (setq pos11 (1+ pos11)))
+;;    (while (and (> pos12 0) (not (= (aref epat1 (1- pos12)) ?*)))
+;;      (setq pos12 (1- pos12)))
+;;
+;;    (setq pos21 0
+;;        len  (length epat2)
+;;        pos22 len)
+;;    (while (and (< pos21 len) (not (= (aref epat2 pos21) ?*)))
+;;      (setq pos21 (1+ pos21)))
+;;    (while (and (> pos22 0) (not (= (aref epat2 (1- pos22)) ?*)))
+;;      (setq pos22 (1- pos22)))
+;;
+;;    (if (and (> (length str1) pos12) (>= pos12 pos11) (> pos11 -1)
+;;           (> (length str2) pos22) (>= pos22 pos21) (> pos21 -1))
+;;      (string= (substring str1 pos11 pos12)
+;;               (substring str2 pos21 pos22)))
+;;    ))
+
+
+;; Prepare meta-buffer in accordance with the argument-function and
+;; redraw-function. Must return the created  meta-buffer.
+(defun ediff-prepare-meta-buffer (action-func meta-list
+                                  meta-buffer-name redraw-function
+                                  jobname &optional startup-hooks)
+  (let* ((meta-buffer-name 
+          (ediff-unique-buffer-name meta-buffer-name "*"))
+         (meta-buffer (get-buffer-create meta-buffer-name)))
+    (ediff-eval-in-buffer meta-buffer
+
+      ;; comes first
+      (ediff-meta-mode)
+
+      (setq ediff-meta-action-function action-func
+            ediff-meta-redraw-function redraw-function
+            ediff-metajob-name jobname
+            ediff-meta-buffer meta-buffer)
+
+      ;; comes after ediff-meta-action-function is set
+      (ediff-setup-meta-map)
+      
+      (if (eq ediff-metajob-name 'ediff-registry)
+          (progn
+            (setq ediff-registry-buffer meta-buffer
+                  ediff-meta-list meta-list)
+            ;; this func is used only from registry buffer, not from other
+            ;; meta-buffs.
+            (define-key
+              ediff-meta-buffer-map "M" 'ediff-show-meta-buff-from-registry))
+        ;; initialize the meta list -- don't do this for registry we prepend
+        ;; '(nil nil) nil to all elts of meta-list, except the first.  The
+        ;; first nil will later be replaced by the session buffer. The second
+        ;; is reserved for session status.
+        ;; (car ediff-meta-list) gets cons'ed with the session group buffer.
+        (setq ediff-meta-list
+              (cons (cons meta-buffer (car meta-list))
+                    (mapcar (function
+                             (lambda (elt)
+                               (cons nil (cons nil elt))))
+                            (cdr meta-list)))))
+        
+      (or (eq meta-buffer ediff-registry-buffer)
+          (setq ediff-session-registry
+                (cons meta-buffer ediff-session-registry)))
+        
+      ;; redraw-function uses ediff-meta-list
+      (funcall redraw-function ediff-meta-list)
+      
+      ;; set read-only/non-modified
+      (setq buffer-read-only t)
+      (set-buffer-modified-p nil)
+
+      (run-hooks 'startup-hooks)
+      ;; arrange for showing directory contents differences
+      ;; must be after run startup-hooks, since ediff-dir-difference-list is
+      ;; set inside these hooks
+      (if (eq action-func 'ediff-dir-action)
+          (progn
+            ;; put meta buffer in (car ediff-dir-difference-list)
+            (setq ediff-dir-difference-list
+                  (cons (cons meta-buffer (car ediff-dir-difference-list))
+                        (cdr ediff-dir-difference-list)))
+
+            (or (ediff-dir1-metajob jobname)
+                (ediff-draw-dir-diffs ediff-dir-difference-list))
+            (define-key ediff-meta-buffer-map "h" 'ediff-mark-for-hiding)
+            (define-key
+              ediff-meta-buffer-map "x" 'ediff-hide-marked-sessions)
+            (define-key ediff-meta-buffer-map "m" 'ediff-mark-for-operation)
+            (if (ediff-collect-diffs-metajob jobname)
+                (define-key
+                  ediff-meta-buffer-map "P" 'ediff-collect-custom-diffs))
+            (define-key ediff-meta-buffer-map "u" 'ediff-up-meta-hierarchy)
+            (define-key ediff-meta-buffer-map "D" 'ediff-show-dir-diffs)))
+
+      (if (eq ediff-metajob-name 'ediff-registry)
+          (run-hooks 'ediff-registry-setup-hook)
+        (run-hooks 'ediff-session-group-setup-hook))
+      ) ; eval in meta-buffer
+    meta-buffer))
+
+
+;; this is a setup function for ediff-directories
+;; must return meta-buffer
+(defun ediff-redraw-directory-group-buffer (meta-list)
+  ;; extract directories
+  (let ((meta-buf (ediff-get-group-buffer meta-list))
+        (empty t)
+        (sessionNum 0)
+        regexp elt session-buf f1 f2 f3 pt 
+        point tmp-list buffer-read-only)
+    (ediff-eval-in-buffer meta-buf
+      (setq point (point))
+      (erase-buffer)
+      (insert (format ediff-meta-buffer-message
+                      (ediff-abbrev-jobname ediff-metajob-name)))
+
+      (setq regexp (ediff-get-group-regexp meta-list))
+      
+      (if (ediff-collect-diffs-metajob)
+          (insert
+           "     `P':\tcollect custom diffs of all marked sessions\n"))
+      (insert
+       "     `u':\tshow parent session group
+     `D':\tdisplay differences among the contents of directories\n\n")
+
+      (if (and (stringp regexp) (> (length regexp) 0))
+          (insert (format "Filter-through regular expression: %s\n" regexp)))
+                          
+      (insert "\n
+        Size  Name
+    -----------------------------------------------------------------------
+
+")
+      
+      ;; discard info on directories and regexp
+      (setq meta-list (cdr meta-list)
+            tmp-list meta-list)
+      (while (and tmp-list empty)
+        (if (and (car tmp-list)
+                 (not (eq (ediff-get-session-status (car tmp-list)) ?I)))
+            (setq empty nil))
+        (setq tmp-list (cdr tmp-list)))
+
+      (if empty
+          (insert
+           "     ******   ******   This session group has no members\n"))
+      
+      ;; now organize file names like this:
+      ;; preferred format:
+      ;;     use-mark sizeA dateA  sizeB dateB  filename
+      ;; I don't have time to mess up with calculating last modtimes
+      ;; (XEmacs has no decode-time function), so
+      ;; the actual format is:
+      ;;     use-mark Size    filename
+      ;; make sure directories are displayed with a trailing slash.
+      ;; If one is a directory and another isn't, indicate this with a `?'
+      (while meta-list
+        (setq elt (car meta-list)
+              meta-list (cdr meta-list)
+              sessionNum (1+ sessionNum))
+        (if (eq (ediff-get-session-status elt) ?I)
+            ()
+          (setq session-buf (ediff-get-session-buffer elt)
+                f1 (ediff-get-session-objA elt)
+                f2 (ediff-get-session-objB elt)
+                f3 (ediff-get-session-objC elt))
+          (setq pt (point))
+          ;; insert markers
+          (insert (cond ((null session-buf) " ") ; virgin session
+                        ((ediff-buffer-live-p session-buf) "+") ;active session
+                        (t "-"))) ; finished session
+          (insert (cond ((ediff-get-session-status elt)) ; session has status,
+                                                       ;;; e.g., ?H, ?I
+                        (t " "))) ; normal session
+          (insert "  Session " (int-to-string sessionNum) ":\n")
+          (ediff-meta-insert-file-info f1)
+          (ediff-meta-insert-file-info f2)
+          (ediff-meta-insert-file-info f3)
+          (ediff-set-meta-overlay pt (point) elt)))
+      (set-buffer-modified-p nil)
+      (goto-char point)
+      meta-buf)))
+
+;; Check if this is a problematic session.
+;; Return nil if not. Otherwise, return symbol representing the problem
+;; At present, problematic sessions occur only in -with-ancestor comparisons
+;; when the ancestor is a directory rather than a file.
+(defun ediff-problematic-session-p (session)
+  (let ((f1 (ediff-get-session-objA session))
+        (f2 (ediff-get-session-objB session))
+        (f3 (ediff-get-session-objC session)))
+    (cond ((and (stringp f1) (not (file-directory-p f1))
+                (stringp f2) (not (file-directory-p f2))
+                (stringp f3) (file-directory-p f3)
+                (ediff-ancestor-metajob))
+           ;; more may be added later
+           'ancestor-is-dir)
+          (t nil))))
+
+(defun ediff-meta-insert-file-info (file)
+  (if (stringp file)
+      (insert
+       (format
+        "  %10d  %s\n"
+        (nth 7 (file-attributes file))
+        ;; dir names in meta lists have no trailing `/' so insert it
+        (cond ((file-directory-p file)
+               (file-name-as-directory (ediff-abbreviate-file-name file)))
+              (t (ediff-abbreviate-file-name file)))))
+    ))
+      
+
+
+(defun ediff-draw-dir-diffs (diff-list)
+  (if (null diff-list) (error "Lost difference info on these directories"))
+  (let* ((buf-name (ediff-unique-buffer-name
+                    "*Ediff File Group Differences" "*"))
+         (regexp (ediff-get-group-regexp diff-list))
+         (dir1 (ediff-abbreviate-file-name (ediff-get-group-objA diff-list)))
+         (dir2 (ediff-abbreviate-file-name (ediff-get-group-objB diff-list)))
+         (dir3 (ediff-get-group-objC diff-list))
+         (dir3 (if (stringp dir3) (ediff-abbreviate-file-name dir3)))
+         (meta-buf (ediff-get-group-buffer diff-list))
+         (underline (make-string 26 ?-))
+         file code 
+         buffer-read-only)
+    ;; skip the directory part
+    (setq diff-list (cdr diff-list))
+    (setq ediff-dir-diffs-buffer (get-buffer-create buf-name))
+    (ediff-eval-in-buffer ediff-dir-diffs-buffer
+      (use-local-map ediff-dir-diffs-buffer-map)
+      (erase-buffer)
+      (setq ediff-meta-buffer meta-buf)
+      (insert "\t\t*** Directory Differences ***\n")
+      (insert "
+Useful commands:
+     `q': hide this buffer
+     SPC: next line
+     DEL: previous line\n\n")
+
+      (if (and (stringp regexp) (> (length regexp) 0))
+          (insert (format "Filter-through regular expression: %s\n" regexp)))
+      (insert "\n")
+      (insert (format "\n%-27s%-26s"
+                      (ediff-truncate-string-left
+                       (ediff-abbreviate-file-name
+                        (file-name-as-directory dir1))
+                       25)
+                      (ediff-truncate-string-left
+                       (ediff-abbreviate-file-name
+                        (file-name-as-directory dir2))
+                       25)))
+      (if dir3
+          (insert (format " %-25s\n"
+                          (ediff-truncate-string-left
+                           (ediff-abbreviate-file-name
+                            (file-name-as-directory dir3))
+                           25)))
+        (insert "\n"))
+      (insert (format "%s%s" underline underline))
+      (if (stringp dir3)
+          (insert (format "%s\n\n" underline))
+        (insert "\n\n"))
+
+      (if (null diff-list)
+          (insert "\n\t***  No differences  ***\n"))
+
+      (while diff-list
+        (setq file (car (car diff-list))
+              code (cdr (car diff-list))
+              diff-list (cdr diff-list))
+        (if (= (mod code 2) 0) ; dir1
+            (insert (format "%-27s"
+                            (ediff-truncate-string-left
+                             (ediff-abbreviate-file-name
+                              (if (file-directory-p (concat dir1 file))
+                                  (file-name-as-directory file)
+                                file))
+                             24)))
+          (insert (format "%-27s" "---")))
+        (if (= (mod code 3) 0) ; dir2
+            (insert (format "%-26s"
+                            (ediff-truncate-string-left
+                             (ediff-abbreviate-file-name
+                              (if (file-directory-p (concat dir2 file))
+                                  (file-name-as-directory file)
+                                file))
+                             24)))
+          (insert (format "%-26s" "---")))
+        (if (stringp dir3)
+            (if (= (mod code 5) 0) ; dir3
+                (insert (format " %-25s" 
+                                (ediff-truncate-string-left
+                                 (ediff-abbreviate-file-name
+                                  (if (file-directory-p (concat dir3 file))
+                                      (file-name-as-directory file)
+                                    file))
+                                 24)))
+              (insert (format " %-25s" "---"))))
+        (insert "\n"))
+      (setq buffer-read-only t)
+      (set-buffer-modified-p nil)) ; eval in diff buffer
+  ))
+
+(defun ediff-bury-dir-diffs-buffer ()
+  "Bury the directory difference buffer. Display the meta buffer instead."
+  (interactive)
+  (let ((buf ediff-meta-buffer)
+        wind)
+    (bury-buffer)
+    (if (setq wind (ediff-get-visible-buffer-window buf))
+        (select-window wind)
+      (set-window-buffer (selected-window) buf))))
+
+;; executes in dir session group buffer
+;; show buffer differences
+(defun ediff-show-dir-diffs ()
+  "Display differences among the directories involved in session group."
+  (interactive)
+  (if (ediff-dir1-metajob)
+      (error "This command is inapplicable in the present context"))
+  (or (ediff-buffer-live-p ediff-dir-diffs-buffer)
+      (ediff-draw-dir-diffs ediff-dir-difference-list))
+  (let ((buf ediff-dir-diffs-buffer))
+    (other-window 1)
+    (set-window-buffer (selected-window) buf)
+    (goto-char (point-min))))
+
+(defun ediff-up-meta-hierarchy ()
+  "Go to the parent session group buffer."
+  (interactive)
+  (if (ediff-buffer-live-p ediff-parent-meta-buffer)
+      (ediff-show-meta-buffer ediff-parent-meta-buffer)
+    (error "This session group has no parent")))
+  
+
+;; argument is ignored
+(defun ediff-redraw-registry-buffer (&optional ignore)
+  (ediff-eval-in-buffer ediff-registry-buffer
+    (let ((point (point))
+          elt bufAname bufBname bufCname cur-diff total-diffs pt
+          job-name meta-list registry-list buffer-read-only)
+      (erase-buffer)
+      (insert "This is a registry of all active Ediff sessions.
+
+Useful commands:
+     button2, `v', RET over a session record:  switch to that session
+     `M' over a session record:  display the associated session group
+     `R' in any Ediff session:   display session registry
+     SPC:\tnext session
+     DEL:\tprevious session
+     `E':\tbrowse Ediff on-line manual
+     `q':\tbury registry
+
+
+\t\tActive Ediff Sessions:
+\t\t----------------------
+
+")
+      ;; purge registry list from dead buffers
+      (mapcar (function (lambda (elt)
+                          (if (not (ediff-buffer-live-p elt))
+                              (setq ediff-session-registry
+                                    (delq elt ediff-session-registry)))))
+              ediff-session-registry)
+
+      (if (null ediff-session-registry)
+          (insert "       ******* No active Ediff sessions *******\n"))
+
+      (setq registry-list ediff-session-registry)
+      (while registry-list
+        (setq elt (car registry-list)
+              registry-list (cdr registry-list))
+        
+        (if (ediff-buffer-live-p elt)
+            (if (ediff-eval-in-buffer elt
+                  (setq job-name ediff-metajob-name
+                        meta-list ediff-meta-list)
+                  (and ediff-metajob-name
+                       (not (eq ediff-metajob-name 'ediff-registry))))
+                (progn
+                  (setq pt (point))
+                  (insert (format "  *group*\t%s: %s\n"
+                                  (buffer-name elt)
+                                  (ediff-abbrev-jobname job-name)))
+                  (insert (format "\t\t   %s   %s   %s\n"
+                                  (ediff-abbreviate-file-name
+                                   (ediff-get-group-objA meta-list))
+                                  (ediff-abbreviate-file-name
+                                   (or (ediff-get-group-objB meta-list) ""))
+                                  (ediff-abbreviate-file-name
+                                   (or (ediff-get-group-objC meta-list) ""))))
+                  (ediff-set-meta-overlay pt (point) elt))
+              (progn
+                (ediff-eval-in-buffer elt
+                  (setq bufAname (if (ediff-buffer-live-p ediff-buffer-A)
+                                     (buffer-name ediff-buffer-A)
+                                   "!!!killed buffer!!!")
+                        bufBname (if (ediff-buffer-live-p ediff-buffer-B)
+                                     (buffer-name ediff-buffer-B)
+                                   "!!!killed buffer!!!")
+                        bufCname (cond ((not (ediff-3way-job))
+                                        "")
+                                       ((ediff-buffer-live-p ediff-buffer-C)
+                                        (buffer-name ediff-buffer-C))
+                                       (t "!!!killed buffer!!!")))
+                  (setq total-diffs (format "%-4d" ediff-number-of-differences)
+                        cur-diff
+                        (cond ((= ediff-current-difference -1) "   _")
+                              ((= ediff-current-difference
+                                  ediff-number-of-differences)
+                               "   $")
+                              (t (format
+                                  "%4d" (1+ ediff-current-difference))))
+                        job-name ediff-job-name))
+                ;; back in the meta buf
+                (setq pt (point))
+                (insert cur-diff "/" total-diffs "\t"
+                        (buffer-name elt)
+                        (format ": %s"  (ediff-abbrev-jobname job-name)))
+                (insert
+                 "\n\t\t   " bufAname "   " bufBname "   " bufCname "\n")
+                (ediff-set-meta-overlay pt (point) elt))))
+        ) ; while
+      (set-buffer-modified-p nil)
+      (goto-char point)
+      )))
+
+;; sets overlay around a meta record with 'ediff-meta-info property PROP
+(defun ediff-set-meta-overlay (b e prop)
+  (let (overl)
+    (setq overl (ediff-make-overlay b e))
+    (if ediff-emacs-p
+        (ediff-overlay-put overl 'mouse-face 'highlight)
+      (ediff-overlay-put overl 'highlight t))
+    (ediff-overlay-put overl 'ediff-meta-info prop)))
+
+(defun ediff-mark-for-hiding (unmark)
+  "Mark session for hiding. With prefix arg, unmark."
+  (interactive "P")
+  (let* ((pos (ediff-event-point last-command-event))
+         (meta-buf (ediff-event-buffer last-command-event))
+         ;; ediff-get-meta-info gives error if meta-buf or pos are invalid
+         (info (ediff-get-meta-info meta-buf pos))
+         (session-buf (ediff-get-session-buffer info)))
+
+    (if unmark
+        (ediff-set-session-status info nil)
+      (if (ediff-buffer-live-p session-buf)
+          (error "Can't hide active session, %s" (buffer-name session-buf)))
+      (ediff-set-session-status info ?H))
+    (ediff-update-meta-buffer meta-buf)
+    ))
+
+(defun ediff-mark-for-operation (unmark)
+  "Mark session for a group operation. With prefix arg, unmark."
+  (interactive "P")
+  (let* ((pos (ediff-event-point last-command-event))
+         (meta-buf (ediff-event-buffer last-command-event))
+         ;; ediff-get-meta-info gives error if meta-buf or pos are invalid
+         (info (ediff-get-meta-info meta-buf pos)))
+
+    (if unmark
+        (ediff-set-session-status info nil)
+      (ediff-set-session-status info ?*))
+    (ediff-update-meta-buffer meta-buf)
+    ))
+
+(defun ediff-hide-marked-sessions (unhide)
+  "Hide marked sessions. With prefix arg, unhide."
+  (interactive "P")
+  (let ((grp-buf (ediff-get-group-buffer ediff-meta-list))
+        (meta-list (cdr ediff-meta-list))
+        (from (if unhide ?I ?H))
+        (to (if unhide ?H ?I))
+        (numMarked 0)
+        elt)
+    (while meta-list
+      (setq elt (car meta-list)
+            meta-list (cdr meta-list))
+      (if (eq (ediff-get-session-status elt) from)
+          (progn
+            (setq numMarked (1+ numMarked))
+            (ediff-set-session-status elt to))))
+    (if (> numMarked 0)
+        (ediff-update-meta-buffer grp-buf)
+      (beep)
+      (if unhide
+          (message "Nothing to reveal...")
+        (message "Nothing to hide...")))
+    ))
+
+;; Apply OPERATION to marked sessions. Operation expects one argument of type
+;; meta-list member (not the first one), i.e., a regular session description.
+;; Returns number of marked sessions on which operation was performed
+(defun ediff-operate-on-marked-sessions (operation)
+  (let ((grp-buf (ediff-get-group-buffer ediff-meta-list))
+        (meta-list (cdr ediff-meta-list))
+        (marksym ?*)
+        (numMarked 0)
+        (sessionNum 0)
+        elt)
+    (while meta-list
+      (setq elt (car meta-list)
+            meta-list (cdr meta-list)
+            sessionNum (1+ sessionNum))
+      (if (eq (ediff-get-session-status elt) marksym)
+          (save-excursion
+            (setq numMarked (1+ numMarked))
+            (funcall operation elt sessionNum))))
+    (ediff-update-meta-buffer grp-buf) ; just in case
+    numMarked
+    ))
+
+(defun ediff-append-custom-diff (session sessionNum)
+  (or (ediff-collect-diffs-metajob)
+      (error "Sorry, I don't do this for everyone..."))
+  (let ((session-buf (ediff-get-session-buffer session))
+        (meta-diff-buff ediff-meta-diff-buffer)
+        (metajob ediff-metajob-name)
+        tmp-buf custom-diff-buf)
+    (if (ediff-buffer-live-p session-buf)
+        (ediff-eval-in-buffer session-buf
+          (if (eq ediff-control-buffer session-buf) ; individual session
+              (setq custom-diff-buf ediff-custom-diff-buffer))))
+
+    (or (ediff-buffer-live-p meta-diff-buff)
+        (error "Ediff: something wrong--no multiple diffs buffer"))
+
+    (cond ((ediff-buffer-live-p custom-diff-buf)
+           (save-excursion
+             (set-buffer meta-diff-buff)
+             (goto-char (point-max))
+             (insert-buffer custom-diff-buf)
+             (insert "\n")))
+          ((eq metajob 'ediff-directories)
+           ;; get diffs by calling shell command on ediff-custom-diff-program
+           (save-excursion
+             (set-buffer (setq tmp-buf (get-buffer-create ediff-tmp-buffer)))
+             (erase-buffer)
+             (shell-command
+              (format "%s %s %s %s"
+                      ediff-custom-diff-program ediff-custom-diff-options
+                      (ediff-get-session-objA session)
+                      (ediff-get-session-objB session))
+              t))
+           (save-excursion
+             (set-buffer meta-diff-buff)
+             (goto-char (point-max))
+             (insert-buffer tmp-buf)
+             (insert "\n")))
+          (t
+           (error
+            "Session %d is marked but inactive--can't make its diff"
+            sessionNum)))
+          ))
+
+(defun ediff-collect-custom-diffs ()
+  "Collect custom diffs of marked sessions in buffer `*Ediff Multifile Diffs*'.
+This operation is defined only for `ediff-directories' and
+`ediff-directory-revisions', since its intent is to produce
+multifile patches. For `ediff-directory-revisions', we insist that
+all marked sessions must be active."
+  (interactive)
+  (or (ediff-buffer-live-p ediff-meta-diff-buffer)
+      (setq ediff-meta-diff-buffer
+            (get-buffer-create
+             (ediff-unique-buffer-name "*Ediff Multifile Diffs" "*"))))
+  (ediff-eval-in-buffer ediff-meta-diff-buffer
+    (erase-buffer))
+  (if (> (ediff-operate-on-marked-sessions 'ediff-append-custom-diff) 0)
+      ;; did something
+      (display-buffer ediff-meta-diff-buffer 'not-this-window)
+    (beep)
+    (message "No marked sessions found")))
+
+              
+;; This function executes in meta buffer. It knows where event happened.
+(defun ediff-dir-action ()
+  "Execute appropriate action for the selected session."
+  (interactive)
+  (let* ((pos (ediff-event-point last-command-event))
+         (meta-buf (ediff-event-buffer last-command-event))
+         ;; ediff-get-meta-info gives error if meta-buf or pos are invalid
+         (info (ediff-get-meta-info meta-buf pos))
+         session-buf file1 file2 file3 regexp)
+
+    (setq session-buf (ediff-get-session-buffer info)
+          file1 (ediff-get-session-objA info)
+          file2 (ediff-get-session-objB info)
+          file3 (ediff-get-session-objC info))
+
+    ;; make sure we don't start on hidden sessions
+    ;; ?H means marked for hiding. ?I means invalid (hidden).
+    (if (memq (ediff-get-session-status info) '(?H ?I))
+        (progn
+          (beep)
+          (if (y-or-n-p "This session is marked as hidden, unmark? ")
+              (progn
+                (ediff-set-session-status info nil)
+                (ediff-update-meta-buffer meta-buf))
+            (error "Aborted"))))
+
+    (ediff-eval-in-buffer meta-buf
+      (goto-char pos) ; if the user clicked on session--move point there
+      ;; First handle sessions involving directories (which are themselves
+      ;; session groups)
+      ;; After that handle individual sessions
+      (cond ((and (file-directory-p file1) 
+                  (stringp file2) (file-directory-p file2)
+                  (if (stringp file3) (file-directory-p file1) t))
+             ;; do ediff/ediff-merge on subdirectories
+             (if (ediff-buffer-live-p session-buf)
+                 (ediff-show-meta-buffer session-buf)
+               (setq regexp (read-string "Filter through regular expression: " 
+                                         nil 'ediff-filtering-regexp-history))
+               (ediff-directories-internal
+                file1 file2 file3 regexp
+                ediff-session-action-function
+                ediff-metajob-name 
+                ;; make it update car info after startup
+                (` (list (lambda () 
+                           ;; child session group should know its parent
+                           (setq ediff-parent-meta-buffer
+                                 (quote (, ediff-meta-buffer)))
+                           ;; and parent will know its child
+                           (setcar (quote (, info)) ediff-meta-buffer)))))))
+
+            ;; Do ediff-revision on a subdirectory
+            ((and (ediff-dir1-metajob) (file-directory-p file1))
+             (if (ediff-buffer-live-p session-buf)
+                 (ediff-show-meta-buffer session-buf)
+               (setq regexp (read-string "Filter through regular expression: " 
+                                         nil 'ediff-filtering-regexp-history))
+               (ediff-directory-revisions-internal
+                file1 regexp
+                ediff-session-action-function ediff-metajob-name
+                ;; make it update car info after startup
+                (` (list (lambda () 
+                           ;; child session group should know its parent
+                           (setq ediff-parent-meta-buffer
+                                 (quote (, ediff-meta-buffer)))
+                           ;; and parent will know its child
+                           (setcar (quote (, info)) ediff-meta-buffer)))))))
+
+            ;; From here on---only individual session handlers
+
+            ;; handle an individual session with live control buffer
+            ((ediff-buffer-live-p session-buf)
+             (ediff-eval-in-buffer session-buf
+               (setq ediff-mouse-pixel-position (mouse-pixel-position))
+               (ediff-recenter 'no-rehighlight)))
+
+            ((ediff-problematic-session-p info)
+             (beep)
+             (if (y-or-n-p
+                  "This session's ancestor is a directory, merge without the ancestor? ")
+                 (ediff-merge-files
+                  file1 file2
+                  ;; arrange startup hooks 
+                  (` (list (lambda () 
+                             (setq ediff-meta-buffer (, (current-buffer)))
+                             ;; see below for the explanation of what this does
+                             (setcar
+                              (quote (, info)) ediff-control-buffer)))))
+               (error "Aborted")))
+            ((ediff-dir1-metajob)       ; needs 1 file arg
+             (funcall ediff-session-action-function
+                      file1
+                      ;; arrange startup hooks 
+                      (` (list (lambda () 
+                                 (setq ediff-meta-buffer (, (current-buffer)))
+                                 ;; see below for explanation of what this does
+                                 (setcar
+                                  (quote (, info)) ediff-control-buffer))))))
+            ((not (ediff-metajob3))      ; need 2 file args
+             (funcall ediff-session-action-function
+                      file1 file2
+                      ;; arrange startup hooks 
+                      (` (list (lambda () 
+                                 (setq ediff-meta-buffer (, (current-buffer)))
+                                 ;; this makes ediff-startup pass the value of
+                                 ;; ediff-control-buffer back to the meta
+                                 ;; level, to the record in the meta list
+                                 ;; containing the information about the
+                                 ;; session associated with that
+                                 ;; ediff-control-buffer
+                                 (setcar
+                                  (quote (, info)) ediff-control-buffer))))))
+            ((ediff-metajob3)      ; need 3 file args
+             (funcall ediff-session-action-function
+                      file1 file2 file3
+                      ;; arrange startup hooks 
+                      (` (list (lambda () 
+                                 (setq ediff-meta-buffer (, (current-buffer)))
+                                 (setcar
+                                  (quote (, info)) ediff-control-buffer))))))
+            ) ; cond
+      ) ; eval in meta-buf
+    ))
+
+(defun ediff-registry-action ()
+  "Switch to a selected session."
+  (interactive)
+  (let* ((pos (ediff-event-point last-command-event))
+         (buf (ediff-event-buffer last-command-event))
+         (ctl-buf (ediff-get-meta-info buf pos)))
+
+    (if (ediff-buffer-live-p ctl-buf)
+        ;; check if this is ediff-control-buffer or ediff-meta-buffer
+        (if (ediff-eval-in-buffer ctl-buf
+              (eq (key-binding "q") 'ediff-quit-meta-buffer))
+            ;; it's a meta-buffer -- last action should just display it
+            (ediff-show-meta-buffer ctl-buf)
+          ;; it's a session buffer -- invoke go back to session
+          (ediff-eval-in-buffer ctl-buf
+            (setq ediff-mouse-pixel-position (mouse-pixel-position))
+            (ediff-recenter 'no-rehighlight)))
+      (beep)
+      (message "You've selected a stale session --- try again")
+      (ediff-update-registry))
+    (ediff-eval-in-buffer buf
+      (goto-char pos))
+    ))
+
+
+(defun ediff-show-meta-buffer (&optional meta-buf)
+  "Show the session group buffer."
+  (interactive)
+  (let (wind frame silent)
+    (if meta-buf (setq silent t))
+
+    (setq meta-buf (or meta-buf ediff-meta-buffer))
+    (cond ((not (bufferp meta-buf))
+           (error "This Ediff session is not part of a session group"))
+          ((not (ediff-buffer-live-p meta-buf))
+           (error
+            "Can't find this session's group panel -- session itself is ok")))
+
+    (ediff-cleanup-meta-buffer meta-buf)
+    (ediff-eval-in-buffer meta-buf
+      (save-excursion
+        (cond ((setq wind (ediff-get-visible-buffer-window meta-buf))
+               (or silent
+                   (message
+                    "Already showing the group panel for this session"))
+               (set-window-buffer wind meta-buf)
+               (select-window wind))
+              ((window-live-p (setq wind ediff-window-C)) ;in merge--merge buf
+               (set-window-buffer ediff-window-C meta-buf)
+               (select-window wind))
+              ((window-live-p (setq wind ediff-window-A))
+               (set-window-buffer ediff-window-A meta-buf)
+               (select-window wind))
+              ((window-live-p (setq wind ediff-window-B))
+               (set-window-buffer ediff-window-B meta-buf)
+               (select-window wind))
+              ((and
+                (setq wind
+                      (ediff-get-visible-buffer-window ediff-registry-buffer))
+                (ediff-window-display-p))
+               (select-window wind)
+               (other-window 1)
+               (set-window-buffer (selected-window) meta-buf))
+              (t (ediff-skip-unsuitable-frames 'ok-unsplittable)
+                 (set-window-buffer (selected-window) meta-buf)))
+        ))
+    (if (ediff-window-display-p)
+        (progn
+          (setq frame
+                (window-frame (ediff-get-visible-buffer-window meta-buf)))
+          (raise-frame frame)
+          (ediff-reset-mouse frame)))
+    (run-hooks 'ediff-show-session-group-hook)
+    ))
+
+(defun ediff-show-meta-buff-from-registry ()
+  "Display the session group buffer for a selected session group."
+  (interactive)
+  (let* ((pos (ediff-event-point last-command-event))
+         (meta-buf (ediff-event-buffer last-command-event))
+         (info (ediff-get-meta-info meta-buf pos))
+         (meta-or-session-buf info))
+    (ediff-eval-in-buffer meta-or-session-buf
+      (ediff-show-meta-buffer))))
+
+;;;###autoload
+(defun ediff-show-registry ()
+  "Display Ediff's registry."
+  (interactive)
+  (ediff-update-registry)
+  (if (not (ediff-buffer-live-p ediff-registry-buffer))
+      (error "No active Ediff sessions or corrupted session registry"))
+  (let (wind frame)
+    ;; for some reason, point moves in ediff-registry-buffer, so we preserve it
+    ;; explicity
+    (ediff-eval-in-buffer ediff-registry-buffer
+      (save-excursion
+        (cond  ((setq wind
+                      (ediff-get-visible-buffer-window ediff-registry-buffer))
+                (message "Already showing the registry")
+                (set-window-buffer wind ediff-registry-buffer)
+                (select-window wind))
+               ((window-live-p ediff-window-C)
+                (set-window-buffer ediff-window-C ediff-registry-buffer)
+                (select-window ediff-window-C))
+               ((window-live-p ediff-window-A)
+                (set-window-buffer ediff-window-A ediff-registry-buffer)
+                (select-window ediff-window-A))
+               ((window-live-p ediff-window-B)
+                (set-window-buffer ediff-window-B ediff-registry-buffer)
+                (select-window ediff-window-B))
+               ((and (setq wind
+                           (ediff-get-visible-buffer-window ediff-meta-buffer))
+                     (ediff-window-display-p))
+                (select-window wind)
+                (other-window 1)
+                (set-window-buffer (selected-window) ediff-registry-buffer))
+               (t (ediff-skip-unsuitable-frames 'ok-unsplittable)
+                  (set-window-buffer (selected-window) ediff-registry-buffer)))
+        ))
+    (if (ediff-window-display-p)
+        (progn
+          (setq frame 
+                (window-frame
+                 (ediff-get-visible-buffer-window ediff-registry-buffer)))
+          (raise-frame frame)
+          (ediff-reset-mouse frame)))
+    (run-hooks 'ediff-show-registry-hook)
+    ))
+
+;;;###autoload
+(defalias 'eregistry 'ediff-show-registry)
+
+;; If meta-buf doesn't exist, it is created. In that case, id doesn't have a
+;; parent meta-buf
+;; Check if META-BUF exists before calling this function
+(defun ediff-update-meta-buffer (meta-buf)
+  (ediff-eval-in-buffer (current-buffer)
+    (if (ediff-buffer-live-p meta-buf)
+        (ediff-eval-in-buffer meta-buf
+          (funcall ediff-meta-redraw-function ediff-meta-list))
+      )))
+
+(defun ediff-update-registry ()
+  (ediff-eval-in-buffer (current-buffer)
+    (if (ediff-buffer-live-p ediff-registry-buffer)
+        (ediff-redraw-registry-buffer)
+      (ediff-prepare-meta-buffer 
+       'ediff-registry-action
+       ediff-session-registry
+       "*Ediff Registry"
+       'ediff-redraw-registry-buffer
+       'ediff-registry))
+    ))
+
+;; if meta-buf exists, it is redrawn along with parent. Otherwise, nothing
+;; happens
+(defun ediff-cleanup-meta-buffer (meta-buffer)
+  (if (ediff-buffer-live-p meta-buffer)
+      (ediff-eval-in-buffer meta-buffer
+        (ediff-update-meta-buffer meta-buffer)
+        (if (ediff-buffer-live-p ediff-parent-meta-buffer)
+            (ediff-update-meta-buffer ediff-parent-meta-buffer)))))
+
+;; t if no session in progress
+(defun ediff-safe-to-quit (meta-buffer)
+  (if (ediff-buffer-live-p meta-buffer)
+      (let ((lis ediff-meta-list)
+            (cont t)
+            buffer-read-only)
+        (ediff-update-meta-buffer meta-buffer)
+        (ediff-eval-in-buffer meta-buffer
+          (setq lis (cdr lis)) ; discard the description part of meta-list
+          (while (and cont lis)
+            (if (ediff-buffer-live-p
+                 (ediff-get-group-buffer lis)) ; in progress
+                (setq cont nil))
+            (setq lis (cdr lis)))
+          cont))))
+
+(defun ediff-quit-meta-buffer ()
+  "If no unprocessed sessions in the group, delete the meta buffer.
+If no session is in progress, ask to confirm before deleting meta buffer.
+Otherwise, bury the meta buffer.
+If this is a session registry buffer then just bury it."
+  (interactive)
+  (let* ((buf (current-buffer))
+         (dir-diffs-buffer ediff-dir-diffs-buffer)
+         (meta-diff-buffer ediff-meta-diff-buffer)
+         (parent-buf ediff-parent-meta-buffer)
+         (dont-show-registry (eq buf ediff-registry-buffer)))
+    (if dont-show-registry
+        (bury-buffer)
+      (ediff-cleanup-meta-buffer buf)
+      (cond ((and (ediff-safe-to-quit buf)
+                  (y-or-n-p "Quit this session group? "))
+             (ediff-dispose-of-meta-buffer buf))
+            ((ediff-safe-to-quit buf)
+             (bury-buffer))
+            (t
+             (bury-buffer)
+             (beep)
+             (message
+              "Group has active sessions, panel not deleted")))
+      (ediff-cleanup-meta-buffer parent-buf)
+      (ediff-kill-buffer-carefully dir-diffs-buffer)
+      (ediff-kill-buffer-carefully meta-diff-buffer)
+      (if (ediff-buffer-live-p parent-buf)
+          (progn
+            (setq dont-show-registry t)
+            (ediff-show-meta-buffer parent-buf)))
+      )
+    (or dont-show-registry
+        (ediff-show-registry))))
+
+(defun ediff-dispose-of-meta-buffer (buf)
+  (setq ediff-session-registry (delq buf ediff-session-registry))
+  (ediff-eval-in-buffer buf
+    (if (ediff-buffer-live-p ediff-dir-diffs-buffer)
+        (kill-buffer ediff-dir-diffs-buffer)))
+  (kill-buffer buf))
+    
+
+;; obtain information on a meta record where the user clicked or typed
+;; BUF is the buffer where this happened and POINT is the position
+;; If optional NOERROR arg is given, don't report error and return nil if no
+;; meta info is found on line.
+(defun ediff-get-meta-info (buf point &optional noerror)
+  (let (result olist tmp)
+    (if (and point (ediff-buffer-live-p buf))
+        (ediff-eval-in-buffer buf
+          (if ediff-xemacs-p
+              (setq result
+                    (if (setq tmp (extent-at point buf 'ediff-meta-info))
+                        (ediff-overlay-get tmp 'ediff-meta-info)))
+            (setq olist (overlays-at point))
+            (setq olist
+                  (mapcar (function (lambda (elt)
+                                      (overlay-get elt 'ediff-meta-info)))
+                          olist))
+            (while (and olist (null (car olist))
+                        (overlay-get (car olist) 'invisible))
+              (setq olist (cdr olist)))
+            (setq result (car olist)))))
+    (if result
+        result
+      (if noerror
+          nil
+        (ediff-update-registry)
+        (error "No session info in this line")))))
+
+;; return location of the next meta overlay after point
+(defun ediff-next-meta-overlay-start (point)
+  (let (overl)
+    (if ediff-xemacs-p
+        (progn
+          (setq overl (extent-at point (current-buffer) 'ediff-meta-info))
+          (if overl
+              (setq overl (next-extent overl))
+            (setq overl (next-extent (current-buffer))))
+          (if overl
+              (extent-start-position overl)
+            (point-max)))
+      (if (= point (point-max)) (setq point (point-min)))
+      (setq overl (car (overlays-at point)))
+      (if (and overl (overlay-get overl 'ediff-meta-info))
+          (overlay-end overl)
+        (next-overlay-change point)))))
+
+(defun ediff-previous-meta-overlay-start (point)
+  (let (overl)
+    (if ediff-xemacs-p
+        (progn
+          (setq overl (extent-at point (current-buffer) 'ediff-meta-info))
+          (if overl
+              (setq overl (previous-extent overl))
+            (setq overl (previous-extent (current-buffer))))
+          (if overl
+              (extent-start-position overl)
+            (point-max)))
+      ;;(if (bobp) (setq point (point-max)))
+      (setq overl (car (overlays-at point)))
+      (setq point (if (and overl (overlay-get overl 'ediff-meta-info))
+                      (previous-overlay-change (overlay-start overl))
+                    (previous-overlay-change point)))
+      (if (= point (point-min)) (point-max) point)
+      )))
+
+
+;;; Local Variables:
+;;; eval: (put 'ediff-defvar-local 'lisp-indent-hook 'defun)
+;;; eval: (put 'ediff-eval-in-buffer 'lisp-indent-hook 1)
+;;; End:
+
+(provide 'ediff-meta)
+(require 'ediff-util)
+
+;;; ediff-meta.el ends here