Rewrite hl-line-mode

The fashion of dual global and minor modes, each managing a replica of
state, has long been outmoded by globalized minor modes (nee
easy-mmode-define-global-mode) around the turn of the century.

* lisp/calendar/todo-mode.el (todo-toggle-item-highlighting,
todo-hl-line-range, todo-modes-set-2): Adapt to new
hl-line-highlight-hook.
* lisp/hl-line.el (hl-line-overlay): Rename hl-line--overlay.
(global-hl-line-overlay, global-hl-line-overlays,
global-hl-line-sticky-flag, hl-line-overlay-buffer,
hl-line-range-function): Obsolesce.
(hl-line--overlay): Erstwhile hl-line-overlay.
(hl-line, hl-line-face): Consolidate.
(hl-line-sticky-flag): Say less (Gen Z Hospital).
(hl-line-overlay-priority): Make this a custom.
(hl-line-highlight-hook): Prefer hook over specialized
hl-line-range-function.
(hl-line-mode): Say less (Gen Z Hospital).
(hl-line-make-overlay): Remove
(hl-line-highlight, hl-line-unhighlight): Rewrite.
(hl-line-maybe-unhighlight): Remove.
(hl-line-turn-on): Necessary for globalized minor mode.
(global-hl-line-mode, global-hl-line-highlight,
global-hl-line-highlight-all, global-hl-line-unhighlight,
global-hl-line-maybe-unhighlight, global-hl-line-unhighlight-all):
Prefer globalized minor mode.
(hl-line-move, hl-line-unload-function): Remove.
* test/lisp/calendar/todo-mode-tests.el (todo-test-item-highlighting,
todo-test-done-items-separator06-bol,
todo-test-done-items-separator06-eol,
todo-test-done-items-separator07): Adapt to consolidated face.

1 files changed, 63 insertions, 234 deletions

diff --git a/lisp/hl-line.el b/lisp/hl-line.el
index 8e60ddf6b07..daa24c4fbf3 100644
--- a/lisp/hl-line.el
+++ b/lisp/hl-line.el
@@ -24,274 +24,103 @@
 
 ;;; Commentary:
 
-;; Provides a local minor mode (toggled by M-x hl-line-mode) and
-;; a global minor mode (toggled by M-x global-hl-line-mode) to
-;; highlight, on a suitable terminal, the line on which point is.  The
-;; global mode highlights the current line in the selected window only
-;; (except when the minibuffer window is selected).  This was
-;; implemented to satisfy a request for a feature of Lesser Editors.
-;; The local mode is sticky: it highlights the line about the buffer's
-;; point even if the buffer's window is not selected.  Caveat: the
-;; buffer's point might be different from the point of a non-selected
-;; window.  Set the variable `hl-line-sticky-flag' to nil to make the
-;; local mode behave like the global mode.
-
-;; You probably don't really want to use the global mode; if the
-;; cursor is difficult to spot, try changing its color, relying on
-;; `blink-cursor-mode' or both.  The hookery used might affect
-;; response noticeably on a slow machine.  The local mode may be
-;; useful in non-editing buffers such as Gnus or PCL-CVS though.
-
-;; An overlay is used.  In the non-sticky cases, this overlay is
-;; active only on the selected window.  A hook is added to
-;; `post-command-hook' to activate the overlay and move it to the line
-;; about point.
-
-;; You could make variable `global-hl-line-mode' buffer-local and set
-;; it to nil to avoid highlighting specific buffers, when the global
-;; mode is used.
-
-;; By default the whole line is highlighted.  The range of highlighting
-;; can be changed by defining an appropriate function as the
-;; buffer-local value of `hl-line-range-function'.
-
 ;;; Code:
 
-(defvar-local hl-line-overlay nil
-  "Overlay used by Hl-Line mode to highlight the current line.")
+(make-obsolete-variable 'hl-line-overlay nil "29.1")
+(make-obsolete-variable 'global-hl-line-overlay nil "29.1")
+(make-obsolete-variable 'global-hl-line-overlays nil "29.1")
+(make-obsolete-variable 'global-hl-line-sticky-flag nil "29.1")
+(make-obsolete-variable 'hl-line-overlay-buffer nil "29.1")
+(make-obsolete-variable 'hl-line-range-function nil "29.1")
 
-(defvar-local global-hl-line-overlay nil
-  "Overlay used by Global-Hl-Line mode to highlight the current line.")
+(defvar-local hl-line--overlay nil
+  "Keep state else scan entire buffer in `post-command-hook'.")
 
-(defvar global-hl-line-overlays nil
-  "Overlays used by Global-Hl-Line mode in various buffers.
-Global-Hl-Line keeps displaying one overlay in each buffer
-when `global-hl-line-sticky-flag' is non-nil.")
+;; 1. define-minor-mode creates buffer-local hl-line--overlay
+;; 2. overlay wiped by kill-all-local-variables
+;; 3. post-command-hook dupes overlay
+;; Solution: prevent step 2.
+(put 'hl-line--overlay 'permanent-local t)
 
 (defgroup hl-line nil
   "Highlight the current line."
   :version "21.1"
   :group 'convenience)
 
-(defface hl-line
-  '((t :inherit highlight :extend t))
-  "Default face for highlighting the current line in Hl-Line mode."
+(defface hl-line-face '((t :inherit highlight :extend t))
+  "Default face for highlighting the current line in hl-line-mode."
   :version "22.1"
   :group 'hl-line)
 
-(defcustom hl-line-face 'hl-line
-  "Face with which to highlight the current line in Hl-Line mode."
-  :type 'face
-  :group 'hl-line
-  :set (lambda (symbol value)
-	 (set symbol value)
-	 (dolist (buffer (buffer-list))
-	   (with-current-buffer buffer
-	     (when (overlayp hl-line-overlay)
-	       (overlay-put hl-line-overlay 'face hl-line-face))))
-	 (when (overlayp global-hl-line-overlay)
-	   (overlay-put global-hl-line-overlay 'face hl-line-face))))
-
 (defcustom hl-line-sticky-flag t
-  "Non-nil means the HL-Line mode highlight appears in all windows.
-Otherwise Hl-Line mode will highlight only in the selected
-window.  Setting this variable takes effect the next time you use
-the command `hl-line-mode' to turn Hl-Line mode on.
-
-This variable has no effect in Global Highlight Line mode.
-For that, use `global-hl-line-sticky-flag'."
+  "Non-nil to preserve highlighting overlay when focus leaves window."
   :type 'boolean
   :version "22.1"
+  :group 'hl-line
+  :set (lambda (symbol value)
+         (set-default symbol value)
+         (unless value
+           (let ((selected (window-buffer (selected-window))))
+             (dolist (buffer (buffer-list))
+               (unless (eq buffer selected)
+                 (with-current-buffer buffer
+                   (hl-line-unhighlight))))))))
+
+(defcustom hl-line-overlay-priority -50
+  "Priority used on the overlay used by hl-line."
+  :type 'integer
+  :version "22.1"
   :group 'hl-line)
 
-(defcustom global-hl-line-sticky-flag nil
-  "Non-nil means the Global HL-Line mode highlight appears in all windows.
-Otherwise Global Hl-Line mode will highlight only in the selected
-window.  Setting this variable takes effect the next time you use
-the command `global-hl-line-mode' to turn Global Hl-Line mode on."
-  :type 'boolean
-  :version "24.1"
+(defcustom hl-line-highlight-hook nil
+  "After hook for `hl-line-highlight'.
+Currently used in calendar/todo-mode."
+  :type 'hook
   :group 'hl-line)
 
-(defvar hl-line-range-function nil
-  "If non-nil, function to call to return highlight range.
-The function of no args should return a cons cell; its car value
-is the beginning position of highlight and its cdr value is the
-end position of highlight in the buffer.
-It should return nil if there's no region to be highlighted.
-
-This variable is expected to be made buffer-local by modes.")
-
-(defvar hl-line-overlay-buffer nil
-  "Most recently visited buffer in which Hl-Line mode is enabled.")
-
-(defvar hl-line-overlay-priority -50
-  "Priority used on the overlay used by hl-line.")
-
 ;;;###autoload
 (define-minor-mode hl-line-mode
-  "Toggle highlighting of the current line (Hl-Line mode).
-
-Hl-Line mode is a buffer-local minor mode.  If
-`hl-line-sticky-flag' is non-nil, Hl-Line mode highlights the
-line about the buffer's point in all windows.  Caveat: the
-buffer's point might be different from the point of a
-non-selected window.  Hl-Line mode uses the function
-`hl-line-highlight' on `post-command-hook' in this case.
-
-When `hl-line-sticky-flag' is nil, Hl-Line mode highlights the
-line about point in the selected window only."
+  "Toggle highlighting of the current line."
   :group 'hl-line
   (if hl-line-mode
       (progn
-        ;; In case `kill-all-local-variables' is called.
-        (add-hook 'change-major-mode-hook #'hl-line-unhighlight nil t)
         (hl-line-highlight)
-        (setq hl-line-overlay-buffer (current-buffer))
+        (add-hook 'change-major-mode-hook #'hl-line-unhighlight nil t)
 	(add-hook 'post-command-hook #'hl-line-highlight nil t))
     (remove-hook 'post-command-hook #'hl-line-highlight t)
-    (hl-line-unhighlight)
-    (remove-hook 'change-major-mode-hook #'hl-line-unhighlight t)))
-
-(defun hl-line-make-overlay ()
-  (let ((ol (make-overlay (point) (point))))
-    (overlay-put ol 'priority hl-line-overlay-priority) ;(bug#16192)
-    (overlay-put ol 'face hl-line-face)
-    ol))
-
-(defun hl-line-highlight ()
-  "Activate the Hl-Line overlay on the current line."
-  (if hl-line-mode	; Might be changed outside the mode function.
-      (progn
-        (unless (overlayp hl-line-overlay)
-          (setq hl-line-overlay (hl-line-make-overlay))) ; To be moved.
-        (overlay-put hl-line-overlay
-                     'window (unless hl-line-sticky-flag (selected-window)))
-	(hl-line-move hl-line-overlay)
-        (hl-line-maybe-unhighlight))
-    (hl-line-unhighlight)))
+    (remove-hook 'change-major-mode-hook #'hl-line-unhighlight t)
+    (let (hl-line-sticky-flag)
+      (hl-line-unhighlight))))
 
 (defun hl-line-unhighlight ()
-  "Deactivate the Hl-Line overlay on the current line."
-  (when (overlayp hl-line-overlay)
-    (delete-overlay hl-line-overlay)
-    (setq hl-line-overlay nil)))
+  (unless hl-line-sticky-flag
+    (when hl-line--overlay
+      (delete-overlay hl-line--overlay)
+      (setq hl-line--overlay nil))))
 
-(defun hl-line-maybe-unhighlight ()
-  "Maybe deactivate the Hl-Line overlay on the current line.
-Specifically, when `hl-line-sticky-flag' is nil deactivate all
-such overlays in all buffers except the current one."
-  (let ((hlob hl-line-overlay-buffer)
-        (curbuf (current-buffer)))
-    (when (and (buffer-live-p hlob)
-               (not hl-line-sticky-flag)
-               (not (eq curbuf hlob))
-               (not (minibufferp)))
-      (with-current-buffer hlob
-        (hl-line-unhighlight)))
-    (when (and (overlayp hl-line-overlay)
-               (eq (overlay-buffer hl-line-overlay) curbuf))
-      (setq hl-line-overlay-buffer curbuf))))
+(defun hl-line-highlight ()
+  (unless (minibufferp)
+    (unless hl-line--overlay
+      (setq hl-line--overlay
+            (let ((ol (make-overlay (point) (point))))
+              (prog1 ol
+                (overlay-put ol 'priority hl-line-overlay-priority)
+                (overlay-put ol 'face 'hl-line-face)))))
+    (move-overlay hl-line--overlay
+                  (line-beginning-position)
+                  (line-beginning-position 2))
+    (run-hooks 'hl-line-highlight-hook)))
+
+(defun hl-line-turn-on ()
+  (unless (minibufferp)
+    (let (inhibit-quit)
+      (hl-line-mode 1))))
 
 ;;;###autoload
-(define-minor-mode global-hl-line-mode
-  "Toggle line highlighting in all buffers (Global Hl-Line mode).
-
-If `global-hl-line-sticky-flag' is non-nil, Global Hl-Line mode
-highlights the line about the current buffer's point in all live
-windows.
-
-Global-Hl-Line mode uses the function `global-hl-line-highlight'
-on `post-command-hook'."
-  :global t
+(define-globalized-minor-mode global-hl-line-mode
+  hl-line-mode hl-line-turn-on
   :group 'hl-line
-  (if global-hl-line-mode
-      (progn
-        ;; In case `kill-all-local-variables' is called.
-        (add-hook 'change-major-mode-hook #'global-hl-line-unhighlight)
-        (global-hl-line-highlight-all)
-	(add-hook 'post-command-hook #'global-hl-line-highlight))
-    (global-hl-line-unhighlight-all)
-    (remove-hook 'post-command-hook #'global-hl-line-highlight)
-    (remove-hook 'change-major-mode-hook #'global-hl-line-unhighlight)))
-
-(defun global-hl-line-highlight ()
-  "Highlight the current line in the current window."
-  (when global-hl-line-mode	; Might be changed outside the mode function.
-    (unless (window-minibuffer-p)
-      (unless (overlayp global-hl-line-overlay)
-        (setq global-hl-line-overlay (hl-line-make-overlay))) ; To be moved.
-      (unless (member global-hl-line-overlay global-hl-line-overlays)
-	(push global-hl-line-overlay global-hl-line-overlays))
-      (overlay-put global-hl-line-overlay 'window
-		   (unless global-hl-line-sticky-flag
-		     (selected-window)))
-      (hl-line-move global-hl-line-overlay)
-      (global-hl-line-maybe-unhighlight))))
-
-(defun global-hl-line-highlight-all ()
-  "Highlight the current line in all live windows."
-  (walk-windows (lambda (w)
-                  (with-current-buffer (window-buffer w)
-                    (global-hl-line-highlight)))
-                nil t))
-
-(defun global-hl-line-unhighlight ()
-  "Deactivate the Global-Hl-Line overlay on the current line."
-  (when (overlayp global-hl-line-overlay)
-    (delete-overlay global-hl-line-overlay)
-    (setq global-hl-line-overlay nil)))
-
-(defun global-hl-line-maybe-unhighlight ()
-  "Maybe deactivate the Global-Hl-Line overlay on the current line.
-Specifically, when `global-hl-line-sticky-flag' is nil deactivate
-all such overlays in all buffers except the current one."
-  (mapc (lambda (ov)
-	  (let ((ovb (overlay-buffer ov)))
-            (when (and (not global-hl-line-sticky-flag)
-                       (bufferp ovb)
-                       (not (eq ovb (current-buffer)))
-                       (not (minibufferp)))
-	      (with-current-buffer ovb
-                (global-hl-line-unhighlight)))))
-        global-hl-line-overlays))
-
-(defun global-hl-line-unhighlight-all ()
-  "Deactivate all Global-Hl-Line overlays."
-  (mapc (lambda (ov)
-	  (let ((ovb (overlay-buffer ov)))
-	    (when (bufferp ovb)
-		(with-current-buffer ovb
-		  (global-hl-line-unhighlight)))))
-	global-hl-line-overlays)
-  (setq global-hl-line-overlays nil))
-
-(defun hl-line-move (overlay)
-  "Move the Hl-Line overlay.
-If `hl-line-range-function' is non-nil, move the OVERLAY to the position
-where the function returns.  If `hl-line-range-function' is nil, fill
-the line including the point by OVERLAY."
-  (let (tmp b e)
-    (if hl-line-range-function
-	(setq tmp (funcall hl-line-range-function)
-	      b   (car tmp)
-	      e   (cdr tmp))
-      (setq tmp t
-	    b (line-beginning-position)
-	    e (line-beginning-position 2)))
-    (if tmp
-	(move-overlay overlay b e)
-      (move-overlay overlay 1 1))))
-
-(defun hl-line-unload-function ()
-  "Unload the Hl-Line library."
-  (global-hl-line-mode -1)
-  (save-current-buffer
-    (dolist (buffer (buffer-list))
-      (set-buffer buffer)
-      (when hl-line-mode (hl-line-mode -1))))
-  ;; continue standard unloading
-  nil)
+  :version "29.1")
 
 (provide 'hl-line)