Fix interaction of line-dragging with mouse-1-click-follows-link.

* lisp/mouse.el (mouse-drag-line): Rewrite the track-mouse loop.
Implement the mouse-1-click-follows-link handling properly.

* lisp/info.el (Info-link-keymap): Use follow-link mechanism for
header-line links.

Fixes: debbugs:374

1 files changed, 59 insertions, 97 deletions

diff --git a/lisp/mouse.el b/lisp/mouse.el
index c130a27a8e4..a0d10a64945 100644
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -388,10 +388,11 @@ This command must be bound to a mouse click."
 
 ;; Note that `window-in-direction' replaces `mouse-drag-window-above'
 ;; and `mouse-drag-vertical-line-rightward-window' with Emacs 24.1.
+
 (defun mouse-drag-line (start-event line)
-  "Drag some line with the mouse.
+  "Drag a mode line, header line, or vertical line with the mouse.
 START-EVENT is the starting mouse-event of the drag action.  LINE
-must be one of the symbols header, mode, or vertical."
+must be one of the symbols `header', `mode', or `vertical'."
   ;; Give temporary modes such as isearch a chance to turn off.
   (run-hooks 'mouse-leave-buffer-hook)
   (let* ((echo-keystrokes 0)
@@ -400,122 +401,85 @@ must be one of the symbols header, mode, or vertical."
 	 (frame (window-frame window))
 	 (minibuffer-window (minibuffer-window frame))
          (on-link (and mouse-1-click-follows-link
-		       (or mouse-1-click-in-non-selected-windows
-			   (eq window (selected-window)))
 		       (mouse-on-link-p start)))
-	 (resize-minibuffer
-	  ;; Resize the minibuffer window if it's on the same frame as
-	  ;; and immediately below the position window and it's either
-	  ;; active or `resize-mini-windows' is nil.
-	  (and (eq line 'mode)
-	       (eq (window-frame minibuffer-window) frame)
-	       (= (nth 1 (window-edges minibuffer-window))
-		  (nth 3 (window-edges window)))
-	       (or (not resize-mini-windows)
-		   (eq minibuffer-window (active-minibuffer-window)))))
-	 (which-side
-	  (and (eq line 'vertical)
-	       (or (cdr (assq 'vertical-scroll-bars (frame-parameters frame)))
-		   'right)))
-	 done event mouse growth dragged)
+	 (side (and (eq line 'vertical)
+		    (or (cdr (assq 'vertical-scroll-bars
+				   (frame-parameters frame)))
+			'right)))
+	 (draggable t)
+	 event position growth dragged)
     (cond
      ((eq line 'header)
       ;; Check whether header-line can be dragged at all.
       (if (window-at-side-p window 'top)
-	  (setq done t)
+	  (setq draggable nil)
 	(setq window (window-in-direction 'above window t))))
      ((eq line 'mode)
       ;; Check whether mode-line can be dragged at all.
-      (when (and (window-at-side-p window 'bottom)
-		 (not resize-minibuffer))
-	(setq done t)))
+      (and (window-at-side-p window 'bottom)
+	   ;; Allow resizing the minibuffer window if it's on the same
+	   ;; frame as and immediately below the clicked window, and
+	   ;; it's active or `resize-mini-windows' is nil.
+	   (not (and (eq (window-frame minibuffer-window) frame)
+		     (= (nth 1 (window-edges minibuffer-window))
+			(nth 3 (window-edges window)))
+		     (or (not resize-mini-windows)
+			 (eq minibuffer-window
+			     (active-minibuffer-window)))))
+	   (setq draggable nil)))
      ((eq line 'vertical)
-      ;; Get the window to adjust for the vertical case.
-      (setq window
-	    (if (eq which-side 'right)
-		;; If the scroll bar is on the window's right or there's
-		;; no scroll bar at all, adjust the window where the
-		;; start-event occurred.
-		window
-	      ;; If the scroll bar is on the start-event window's left,
-	      ;; adjust the window on the left of it.
-	      (window-in-direction 'left window t)))))
+      ;; Get the window to adjust for the vertical case.  If the
+      ;; scroll bar is on the window's right or there's no scroll bar
+      ;; at all, adjust the window where the start-event occurred.  If
+      ;; the scroll bar is on the start-event window's left, adjust
+      ;; the window on the left of it.
+      (unless (eq side 'right)
+	(setq window (window-in-direction 'left window t)))))
 
     ;; Start tracking.
     (track-mouse
-      ;; Loop reading events and sampling the position of the mouse.
-      (while (not done)
-	(setq event (read-event))
-	(setq mouse (mouse-position))
-	;; Do nothing if
-	;;   - there is a switch-frame event.
-	;;   - the mouse isn't in the frame that we started in
-	;;   - the mouse isn't in any Emacs frame
-	;; Drag if
-	;;   - there is a mouse-movement event
-	;;   - there is a scroll-bar-movement event (??)
-	;;     (same as mouse movement for our purposes)
-	;; Quit if
-	;;   - there is a keyboard event or some other unknown event.
+      ;; Loop reading events and sampling the position of the mouse,
+      ;; until there is a non-mouse-movement event.  Also,
+      ;; scroll-bar-movement events are the same as mouse movement for
+      ;; our purposes.  (Why? -- cyd)
+      (while (progn
+	       (setq event (read-event))
+	       (memq (car-safe event) '(mouse-movement scroll-bar-movement)))
+	(setq position (mouse-position))
 	(cond
-	 ((not (consp event))
-	  (setq done t))
-	 ((memq (car event) '(switch-frame select-window))
-	  nil)
-	 ((not (memq (car event) '(mouse-movement scroll-bar-movement)))
-	  (when (consp event)
-	    ;; Do not unread a drag-mouse-1 event to avoid selecting
-	    ;; some other window.  For vertical line dragging do not
-	    ;; unread mouse-1 events either (but only if we dragged at
-	    ;; least once to allow mouse-1 clicks get through.
-	    (unless (and dragged
-			 (if (eq line 'vertical)
-			     (memq (car event) '(drag-mouse-1 mouse-1))
-			   (eq (car event) 'drag-mouse-1)))
-	      (push event unread-command-events)))
-	  (setq done t))
-	 ((or (not (eq (car mouse) frame)) (null (car (cdr mouse))))
+	 ((or (not (eq (car position) frame))
+	      (null (cadr position)))
 	  nil)
 	 ((eq line 'vertical)
-	  ;; Drag vertical divider (the calculations below are those
-	  ;; from Emacs 23).
-	  (setq growth
-		(- (- (cadr mouse)
-		      (if (eq which-side 'right) 0 2))
-		   (nth 2 (window-edges window))
-		   -1))
+	  ;; Drag vertical divider.
+	  (setq growth (- (cadr position)
+			  (if (eq side 'right) 0 2)
+			  (nth 2 (window-edges window))
+			  -1))
 	  (unless (zerop growth)
-	    ;; Remember that we dragged.
 	    (setq dragged t))
 	  (adjust-window-trailing-edge window growth t))
-	 (t
-	  ;; Drag horizontal divider (the calculations below are those
-	  ;; from Emacs 23).
+	 (draggable
+	  ;; Drag horizontal divider.
 	  (setq growth
 		(if (eq line 'mode)
-		    (- (cddr mouse) (nth 3 (window-edges window)) -1)
+		    (- (cddr position) (nth 3 (window-edges window)) -1)
 		  ;; The window's top includes the header line!
-		  (- (nth 3 (window-edges window)) (cddr mouse))))
-
+		  (- (nth 3 (window-edges window)) (cddr position))))
 	  (unless (zerop growth)
-	    ;; Remember that we dragged.
 	    (setq dragged t))
+	  (adjust-window-trailing-edge window (if (eq line 'mode)
+						  growth
+						(- growth)))))))
+    ;; Process the terminating event.
+    (when (and (mouse-event-p event) on-link (not dragged)
+	       (mouse--remap-link-click-p start-event event))
+      ;; If mouse-2 has never been done by the user, it doesn't have
+      ;; the necessary property to be interpreted correctly.
+      (put 'mouse-2 'event-kind 'mouse-click)
+      (setcar event 'mouse-2))
+    (push event unread-command-events)))
 
-	  (if (eq line 'mode)
-	      (adjust-window-trailing-edge window growth)
-	    (adjust-window-trailing-edge window (- growth))))))
-
-      ;; Presumably, if this was just a click, the last event should be
-      ;; `mouse-1', whereas if this did move the mouse, it should be a
-      ;; `drag-mouse-1'.  `dragged' nil tells us that we never dragged
-      ;; and `on-link' tells us that there is a link to follow.
-      (when (and on-link (not dragged)
-		 (eq 'mouse-1 (car-safe (car unread-command-events))))
-	;; If mouse-2 has never been done by the user, it doesn't
-	;; have the necessary property to be interpreted correctly.
-	(put 'mouse-2 'event-kind 'mouse-click)
-	(setcar unread-command-events
-		(cons 'mouse-2 (cdar unread-command-events)))))))
 
 (defun mouse-drag-mode-line (start-event)
   "Change the height of a window by dragging on the mode line."
@@ -791,10 +755,8 @@ DO-MOUSE-DRAG-REGION-POST-PROCESS should only be used by
 		   ;; Don't count the mode line.
 		   (1- (nth 3 bounds))))
 	 (on-link (and mouse-1-click-follows-link
-		       (or mouse-1-click-in-non-selected-windows
-			   (eq start-window original-window))
                        ;; Use start-point before the intangibility
-                       ;; treatment, in case we click on a link inside an
+                       ;; treatment, in case we click on a link inside
                        ;; intangible text.
                        (mouse-on-link-p start-posn)))
 	 (click-count (1- (event-click-count start-event)))