buff-menu: Add command to unmark all buffers

Bind 'U' in buff-menu, bs and electric-buff-menu to commands
to unmark all buffers (Bug#24880).
* lisp/emacs-lisp/tabulated-list.el (tabulated-list-header-overlay-p):
New predicate; return non-nil if tabulated-list has a fake header.
* lisp/buff-menu.el (Buffer-menu-unmark-all-buffers):
New command; remove all flags that use a particular mark from all the lines.
Bind it to 'M-DEL'.
(Buffer-menu-unmark-all):
New command; remove all flags from all the lines.  Bind it to 'U'.
(Buffer-menu-marker-char, Buffer-menu-del-char): New variables.
(Buffer-menu-delete, Buffer-menu-mark): Use them.
(Buffer-menu-mode-map): Update menus.
(Buffer-menu-mode): Update mode doc.
* lisp/bs.el (bs-unmark-all, bs-unmark-previous): New commands.
(bs-mode-map): Bind them to 'U' and '<backspace>' respectively.
(bs-mode): Update mode doc.
* lisp/ebuff-menu.el (electric-buffer-menu-mode-map):
Bind Buffer-menu-unmark-all to 'U' and Buffer-menu-unmark-all-buffers
to 'M-DEL'.
(bs--down, bs-down, bs--up, bs-up, bs-unmark-current, bs-mark-current):
Use point instead of cursor in doc string.
(electric-buffer-list): Update mode doc.
* doc/emacs/buffers.texi (Several Buffers): Mention Buffer-menu-unmark-all
and Buffer-menu-unmark-all-buffers.
; * etc/NEWS: Add an entry per each new feature.

doc/emacs/buffers.texi

@@ -411,6 +411,18 @@ Remove all flags from the current line, and move down
 @kindex DEL @r{(Buffer Menu)}
 Move to the previous line and remove all flags on that line
 (@code{Buffer-menu-backup-unmark}).
+
+@item M-@key{DEL}
+@findex Buffer-menu-unmark-all-buffers
+@kindex M-DEL @r{(Buffer Menu)}
+Remove a particular flag from all lines
+(@code{Buffer-menu-unmark-all-buffers}).
+
+@item U
+@findex Buffer-menu-unmark-all
+@kindex U @r{(Buffer Menu)}
+Remove all flags from all the lines
+(@code{Buffer-menu-unmark-all}).
 @end table
 
 @noindent

etc/NEWS

@@ -283,6 +283,24 @@ the file's actual content before prompting the user.
 
 * Changes in Specialized Modes and Packages in Emacs 26.1
 
+** Electric-Buffer-menu
+
++++
+*** Key 'U' is bound to 'Buffer-menu-unmark-all' and key 'M-DEL' is
+bound to 'Buffer-menu-unmark-all-buffers'.
+
+** bs
+
+---
+*** Two new commands 'bs-unmark-all', bound to 'U', and
+'bs-unmark-previous', bound to <backspace>.
+
+** Buffer-menu
+
++++
+*** Two new commands 'Buffer-menu-unmark-all', bound to 'U' and
+'Buffer-menu-unmark-all-buffers', bound to 'M-DEL'.
+
 ** Ibuffer
 
 ---

lisp/bs.el

@@ -491,6 +491,8 @@ Used internally, only.")
     (define-key map "t"       'bs-visit-tags-table)
     (define-key map "m"       'bs-mark-current)
     (define-key map "u"       'bs-unmark-current)
+    (define-key map "U"       'bs-unmark-all)
+    (define-key map "\177"    'bs-unmark-previous)
     (define-key map ">"       'scroll-right)
     (define-key map "<"       'scroll-left)
     (define-key map "?"       'bs-help)
@@ -635,6 +637,8 @@ For faster navigation each digit key is a digit argument.
 \\[bs-clear-modified] -- clear modified-flag on that buffer.
 \\[bs-mark-current] -- mark current line's buffer to be displayed.
 \\[bs-unmark-current] -- unmark current line's buffer to be displayed.
+\\[bs-unmark-all] -- unmark all buffer lines.
+\\[bs-unmark-previous] -- unmark previous line's buffer to be displayed.
 \\[bs-show-sorted] -- display buffer list sorted by next sort aspect.
 \\[bs-set-configuration-and-refresh] -- ask user for a configuration and \
 apply selected configuration.
@@ -867,7 +871,7 @@ the status of buffer on current line."
 (defun bs-mark-current (count)
   "Mark buffers.
 COUNT is the number of buffers to mark.
-Move cursor vertically down COUNT lines."
+Move point vertically down COUNT lines."
   (interactive "p")
   (bs--mark-unmark count
 		   (lambda (buf)
@@ -876,12 +880,39 @@ Move cursor vertically down COUNT lines."
 (defun bs-unmark-current (count)
   "Unmark buffers.
 COUNT is the number of buffers to unmark.
-Move cursor vertically down COUNT lines."
+Move point vertically down COUNT lines."
   (interactive "p")
   (bs--mark-unmark count
 		   (lambda (buf)
 		     (setq bs--marked-buffers (delq buf bs--marked-buffers)))))
 
+(defun bs-unmark-previous (count)
+  "Unmark previous COUNT buffers.
+Move point vertically up COUNT lines.
+When called interactively a numeric prefix argument sets COUNT."
+  (interactive "p")
+  (forward-line (- count))
+  (save-excursion (bs-unmark-current count)))
+
+(defun bs-unmark-all ()
+  "Unmark all buffers."
+  (interactive)
+  (let ((marked (string-to-char bs-string-marked))
+        (current (string-to-char bs-string-current))
+        (marked-cur (string-to-char bs-string-current-marked))
+        (unmarked (string-to-char bs-string-show-normally))
+        (inhibit-read-only t))
+    (save-excursion
+      (goto-char (point-min))
+      (forward-line 2)
+      (while (not (eobp))
+        (if (eq (char-after) marked)
+            (subst-char-in-region (point) (1+ (point)) marked unmarked)
+          (when (eq (char-after) marked-cur)
+            (subst-char-in-region (point) (1+ (point)) marked-cur current)))
+        (forward-line 1))
+      (setq bs--marked-buffers nil))))
+
 (defun bs--show-config-message (what)
   "Show message indicating the new showing status WHAT.
 WHAT is a value of nil, `never', or `always'."
@@ -973,14 +1004,14 @@ Uses function `read-only-mode'."
     (apply fun args)))
 
 (defun bs-up (arg)
-  "Move cursor vertically up ARG lines in Buffer Selection Menu."
+  "Move point vertically up ARG lines in Buffer Selection Menu."
   (interactive "p")
   (if (and arg (numberp arg) (< arg 0))
       (bs--nth-wrapper (- arg) 'bs--down)
     (bs--nth-wrapper arg 'bs--up)))
 
 (defun bs--up ()
-  "Move cursor vertically up one line.
+  "Move point vertically up one line.
 If on top of buffer list go to last line."
   (if (> (count-lines 1 (point)) bs-header-lines-length)
       (forward-line -1)
@@ -989,14 +1020,14 @@ If on top of buffer list go to last line."
     (recenter -1)))
 
 (defun bs-down (arg)
-  "Move cursor vertically down ARG lines in Buffer Selection Menu."
+  "Move point vertically down ARG lines in Buffer Selection Menu."
   (interactive "p")
   (if (and arg (numberp arg) (< arg 0))
       (bs--nth-wrapper (- arg) 'bs--up)
     (bs--nth-wrapper arg 'bs--down)))
 
 (defun bs--down ()
-  "Move cursor vertically down one line.
+  "Move point vertically down one line.
 If at end of buffer list go to first line."
   (if (eq (line-end-position) (point-max))
       (progn

lisp/buff-menu.el

@@ -37,6 +37,12 @@
   :group 'tools
   :group 'convenience)
 
+(defvar Buffer-menu-marker-char ?>
+  "The mark character for marked buffers.")
+
+(defvar Buffer-menu-del-char ?D
+  "Character used to flag buffers for deletion.")
+
 (defcustom Buffer-menu-use-header-line t
   "If non-nil, use the header line to display Buffer Menu column titles."
   :type 'boolean
@@ -121,6 +127,8 @@ commands.")
     (define-key map "\177" 'Buffer-menu-backup-unmark)
     (define-key map "~" 'Buffer-menu-not-modified)
     (define-key map "u" 'Buffer-menu-unmark)
+    (define-key map "\M-\177" 'Buffer-menu-unmark-all-buffers)
+    (define-key map "U" 'Buffer-menu-unmark-all)
     (define-key map "m" 'Buffer-menu-mark)
     (define-key map "t" 'Buffer-menu-visit-tags-table)
     (define-key map "%" 'Buffer-menu-toggle-read-only)
@@ -197,6 +205,12 @@ commands.")
     (bindings--define-key menu-map [umk]
       '(menu-item "Unmark" Buffer-menu-unmark
 		 :help "Cancel all requested operations on buffer on this line and move down"))
+    (bindings--define-key menu-map [umkab]
+      '(menu-item "Remove marks..." Buffer-menu-unmark-all-buffers
+                  :help "Cancel a requested operation on all buffers"))
+    (bindings--define-key menu-map [umka]
+      '(menu-item "Unmark all" Buffer-menu-unmark-all
+                  :help "Cancel all requested operations on buffers"))
     (bindings--define-key menu-map [mk]
       '(menu-item "Mark" Buffer-menu-mark
 		 :help "Mark buffer on this line for being displayed by v command"))
@@ -239,6 +253,8 @@ In Buffer Menu mode, the following commands are defined:
 \\[Buffer-menu-execute]    Delete or save marked buffers.
 \\[Buffer-menu-unmark]    Remove all marks from current line.
      With prefix argument, also move up one line.
+\\[Buffer-menu-unmark-all-buffers]    Remove a particular mark from all lines.
+\\[Buffer-menu-unmark-all]    Remove all marks from all lines.
 \\[Buffer-menu-backup-unmark]  Back up a line and remove marks.
 \\[Buffer-menu-toggle-read-only]    Toggle read-only status of buffer on this line.
 \\[revert-buffer]    Update the list of buffers.
@@ -346,7 +362,7 @@ is nil or omitted, and signal an error otherwise."
   "Mark the Buffer menu entry at point for later display.
 It will be displayed by the \\<Buffer-menu-mode-map>\\[Buffer-menu-select] command."
   (interactive)
-  (tabulated-list-set-col 0 ">" t)
+  (tabulated-list-set-col 0 (char-to-string Buffer-menu-marker-char) t)
   (forward-line))
 
 (defun Buffer-menu-unmark (&optional backup)
@@ -356,6 +372,28 @@ Optional prefix arg means move up."
   (Buffer-menu--unmark)
   (forward-line (if backup -1 1)))
 
+(defun Buffer-menu-unmark-all-buffers (mark)
+  "Cancel a requested operation on all buffers.
+MARK is the character to flag the operation on the buffers.
+When called interactively prompt for MARK;  RET remove all marks."
+  (interactive "cRemove marks (RET means all):")
+  (save-excursion
+    (goto-char (point-min))
+    (when (tabulated-list-header-overlay-p)
+      (forward-line))
+    (while (not (eobp))
+      (let ((xmarks (list (aref (tabulated-list-get-entry) 0)
+                          (aref (tabulated-list-get-entry) 2))))
+        (when (or (char-equal mark ?\r)
+                  (member (char-to-string mark) xmarks))
+          (Buffer-menu--unmark)))
+      (forward-line))))
+
+(defun Buffer-menu-unmark-all ()
+  "Cancel all requested operations on buffers."
+  (interactive)
+  (Buffer-menu-unmark-all-buffers ?\r))
+
 (defun Buffer-menu-backup-unmark ()
   "Move up and cancel all requested operations on buffer on line above."
   (interactive)
@@ -382,12 +420,12 @@ buffers to delete; a negative ARG means to delete backwards."
       (setq arg 1))
   (while (> arg 0)
     (when (Buffer-menu-buffer)
-      (tabulated-list-set-col 0 "D" t))
+      (tabulated-list-set-col 0 (char-to-string Buffer-menu-del-char) t))
     (forward-line 1)
     (setq arg (1- arg)))
   (while (< arg 0)
     (when (Buffer-menu-buffer)
-      (tabulated-list-set-col 0 "D" t))
+      (tabulated-list-set-col 0 (char-to-string Buffer-menu-del-char) t))
     (forward-line -1)
     (setq arg (1+ arg))))
 

lisp/ebuff-menu.el

@@ -55,6 +55,8 @@
     (define-key map "\177" 'Buffer-menu-backup-unmark)
     (define-key map "~" 'Buffer-menu-not-modified)
     (define-key map "u" 'Buffer-menu-unmark)
+    (define-key map "\M-\177" 'Buffer-menu-unmark-all-buffers)
+    (define-key map "U" 'Buffer-menu-unmark-all)
     (let ((i ?0))
       (while (<= i ?9)
 	(define-key map (char-to-string i) 'digit-argument)
@@ -114,6 +116,7 @@ Run hooks in `electric-buffer-menu-mode-hook' on entry.
 \\[Buffer-menu-save] -- mark that buffer to be saved.
 \\[Buffer-menu-delete] or \\[Buffer-menu-delete-backwards] -- mark that buffer to be deleted.
 \\[Buffer-menu-unmark] -- remove all kinds of marks from current line.
+\\[Buffer-menu-unmark-all] -- remove all kinds of marks from all lines.
 \\[Electric-buffer-menu-mode-view-buffer] -- view buffer, returning when done.
 \\[Buffer-menu-backup-unmark] -- back up a line and remove marks."
   (interactive "P")

lisp/emacs-lisp/tabulated-list.el

@@ -259,6 +259,12 @@ Do nothing if `tabulated-list--header-string' is nil."
                     (make-overlay (point-min) (point))))
       (overlay-put tabulated-list--header-overlay 'face 'underline))))
 
+(defsubst tabulated-list-header-overlay-p (&optional pos)
+  "Return non-nil if there is a fake header.
+Optional arg POS is a buffer position where to look for a fake header;
+defaults to `point-min'."
+  (overlays-at (or pos (point-min))))
+
 (defun tabulated-list-revert (&rest ignored)
   "The `revert-buffer-function' for `tabulated-list-mode'.
 It runs `tabulated-list-revert-hook', then calls `tabulated-list-print'."