(mouse-drag-header-line): Don't allow window resizing

by dragging a header-line at the top of the frame because that
looks odd.
(mouse-drag-mode-line-1): Use event-* and posn-* functions
instead of treating the event as a list.  Some cleanup.

1 files changed, 45 insertions, 27 deletions

diff --git a/lisp/mouse.el b/lisp/mouse.el
index 90b9a572aeb..f4f35d90673 100644
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -308,22 +308,22 @@ START-EVENT is the starting mouse-event of the drag action.
 MODE-LINE-P non-nil means a mode line is dragged."
   ;; Give temporary modes such as isearch a chance to turn off.
   (run-hooks 'mouse-leave-buffer-hook)
-  (let ((done nil)
-        (echo-keystrokes 0)
-        (start-event-frame (window-frame (car (car (cdr start-event)))))
-        (start-event-window (car (car (cdr start-event))))
-        (start-nwindows (count-windows t))
-        (old-selected-window (selected-window))
-        should-enlarge-minibuffer
-        event mouse minibuffer y top bot edges wconfig params growth)
-    (setq params (frame-parameters))
-    (setq minibuffer (cdr (assq 'minibuffer params)))
+  (let* ((done nil)
+         (echo-keystrokes 0)
+         (start (event-start start-event))
+         (start-event-window (posn-window start))
+         (start-event-frame (window-frame start-event-window))
+         (start-nwindows (count-windows t))
+         (old-selected-window (selected-window))
+         (minibuffer (frame-parameter nil 'minibuffer))
+         should-enlarge-minibuffer event mouse y top bot edges wconfig growth)
     (track-mouse
       (progn
         ;; enlarge-window only works on the selected window, so
         ;; we must select the window where the start event originated.
         ;; unwind-protect will restore the old selected window later.
         (select-window start-event-window)
+        
         ;; if this is the bottommost ordinary window, then to
         ;; move its modeline the minibuffer must be enlarged.
         (setq should-enlarge-minibuffer
@@ -332,11 +332,13 @@ MODE-LINE-P non-nil means a mode line is dragged."
                    (not (one-window-p t))
                    (= (nth 1 (window-edges minibuffer))
                       (nth 3 (window-edges)))))
+        
         ;; loop reading events and sampling the position of
         ;; the mouse.
         (while (not done)
           (setq event (read-event)
                 mouse (mouse-position))
+          
           ;; do nothing if
           ;;   - there is a switch-frame event.
           ;;   - the mouse isn't in the frame that we started in
@@ -350,18 +352,21 @@ MODE-LINE-P non-nil means a mode line is dragged."
           ;;     unknown event.
           (cond ((integerp event)
                  (setq done t))
+                
                 ((eq (car event) 'switch-frame)
                  nil)
-                ((not (memq (car event)
-                            '(mouse-movement scroll-bar-movement)))
-                 (if (consp event)
-                     (setq unread-command-events
-                           (cons event unread-command-events)))
+                
+                ((not (memq (car event) '(mouse-movement scroll-bar-movement)))
+                 (when (consp event)
+                   (push event unread-command-events))
                  (setq done t))
+                
                 ((not (eq (car mouse) start-event-frame))
                  nil)
+                
                 ((null (car (cdr mouse)))
                  nil)
+                
                 (t
                  (setq y (cdr (cdr mouse))
                        edges (window-edges)
@@ -382,10 +387,10 @@ MODE-LINE-P non-nil means a mode line is dragged."
                  (setq wconfig (current-window-configuration))
                  
                  ;; Check for an error case.
-                 (if (and (/= growth 0)
-                          (not minibuffer)
-                          (one-window-p t))
-                     (error "Attempt to resize sole window"))
+                 (when (and (/= growth 0)
+                            (not minibuffer)
+                            (one-window-p t))
+                   (error "Attempt to resize sole window"))
                  
                  ;; grow/shrink minibuffer?
                  (if should-enlarge-minibuffer
@@ -405,7 +410,7 @@ MODE-LINE-P non-nil means a mode line is dragged."
                        (enlarge-window (- growth))
                        (select-window start-event-window))
                    ;; no.  grow/shrink the selected window
-                   ;; (message "growth = %d" growth)
+                   ;(message "growth = %d" growth)
                    (enlarge-window growth))
                  
                  ;; if this window's growth caused another
@@ -418,11 +423,11 @@ MODE-LINE-P non-nil means a mode line is dragged."
                  ;; the minibuffer.  minibuffer size changes
                  ;; can cause all windows to shrink... no way
                  ;; around it.
-                 (if (or (/= start-nwindows (count-windows t))
-                         (and (not should-enlarge-minibuffer)
-                              mode-line-p
-                              (/= top (nth 1 (window-edges)))))
-                     (set-window-configuration wconfig)))))))))
+                 (when (or (/= start-nwindows (count-windows t))
+                           (and (not should-enlarge-minibuffer)
+                                mode-line-p
+                                (/= top (nth 1 (window-edges)))))
+                   (set-window-configuration wconfig)))))))))
 
 (defun mouse-drag-mode-line (start-event)
   "Change the height of a window by dragging on the mode line."
@@ -430,9 +435,22 @@ MODE-LINE-P non-nil means a mode line is dragged."
   (mouse-drag-mode-line-1 start-event t))
 
 (defun mouse-drag-header-line (start-event)
-  "Change the height of a window by dragging on the header line."
+  "Change the height of a window by dragging on the header line.
+Windows whose header-lines are at the top of the frame cannot be
+resized by dragging their header-line."
   (interactive "e")
-  (mouse-drag-mode-line-1 start-event nil))
+  ;; Changing the window's size by dragging its header-line when the
+  ;; header-line is at the top of the frame is somewhat strange,
+  ;; because the header-line doesn't move, so don't do it.
+  (let* ((start (event-start start-event))
+         (window (posn-window start))
+         (frame (window-frame window))
+         (first-window (frame-first-window frame)))
+    (when (or (eq window first-window)
+              (= (nth 1 (window-edges window))
+                 (nth 1 (window-edges first-window))))
+      (error "Cannot move header-line at the top of the frame"))
+    (mouse-drag-mode-line-1 start-event nil)))
 
 
 (defun mouse-drag-vertical-line (start-event)