* lisp/xt-mouse.el: Drop spurious/oddly shaped events.

(xterm-mouse--read-event-sequence-1000): Return nil if something looks fishy.
(xterm-mouse-event): Propagate it.
(xterm-mouse-translate-1): Handle it.

Fixes: debbugs:17378

2 files changed, 62 insertions, 49 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index f8502bd35bb..333bc7fcf90 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,11 @@
+2014-05-08  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * xt-mouse.el: Drop spurious/oddly shaped events (bug#17378).
+        (xterm-mouse--read-event-sequence-1000): Return nil if something
+        looks fishy.
+        (xterm-mouse-event): Propagate it.
+        (xterm-mouse-translate-1): Handle it.
+
 2014-05-07  Stephen Berman  <stephen.berman@gmx.net>
 
         * calendar/todo-mode.el (todo-insert-item--apply-args): When all
diff --git a/lisp/xt-mouse.el b/lisp/xt-mouse.el
index 87e65f7e117..5b34612c2e7 100644
--- a/lisp/xt-mouse.el
+++ b/lisp/xt-mouse.el
@@ -63,8 +63,8 @@ http://invisible-island.net/xterm/ctlseqs/ctlseqs.html)."
 
 (defun xterm-mouse-translate-1 (&optional extension)
   (save-excursion
-    (save-window-excursion
-      (deactivate-mark)
+    (save-window-excursion              ;FIXME: Why?
+      (deactivate-mark)                 ;FIXME: Why?
       (let* ((xterm-mouse-last nil)
              (down (xterm-mouse-event extension))
              (down-command (nth 0 down))
@@ -73,10 +73,10 @@ http://invisible-island.net/xterm/ctlseqs/ctlseqs.html)."
              (down-binding (key-binding (if (symbolp down-where)
                                             (vector down-where down-command)
                                           (vector down-command))))
-             (is-click (string-match "^mouse" (symbol-name (car down)))))
+             (is-down (string-match "down" (symbol-name (car down)))))
 
         ;; Retrieve the expected preface for the up-event.
-        (unless is-click
+        (unless is-down
           (unless (cond ((null extension)
                          (and (eq (read-event) ?\e)
                               (eq (read-event) ?\[)
@@ -88,14 +88,17 @@ http://invisible-island.net/xterm/ctlseqs/ctlseqs.html)."
             (error "Unexpected escape sequence from XTerm")))
 
         ;; Process the up-event.
-        (let* ((click (if is-click down (xterm-mouse-event extension)))
+        (let* ((click (if is-down (xterm-mouse-event extension) down))
                (click-data  (nth 1 click))
                (click-where (nth 1 click-data)))
-          (if (memq down-binding '(nil ignore))
-              (if (and (symbolp click-where)
-                       (consp click-where))
-                  (vector (list click-where click-data) click)
-                (vector click))
+          (cond
+           ((null down) nil)
+           ((memq down-binding '(nil ignore))
+            (if (and (symbolp click-where)
+                     (consp click-where))
+                (vector (list click-where click-data) click)
+              (vector click)))
+           (t
             (setq unread-command-events
                   (append (if (eq down-where click-where)
                               (list click)
@@ -114,7 +117,7 @@ http://invisible-island.net/xterm/ctlseqs/ctlseqs.html)."
             (if (and (symbolp down-where)
                      (consp down-where))
                 (vector (list down-where down-data) down)
-              (vector down))))))))
+              (vector down)))))))))
 
 ;; These two variables have been converted to terminal parameters.
 ;;
@@ -153,7 +156,8 @@ http://invisible-island.net/xterm/ctlseqs/ctlseqs.html)."
 ;; Normal terminal mouse click reporting: expect three bytes, of the
 ;; form <BUTTON+32> <X+32> <Y+32>.  Return a list (EVENT-TYPE X Y).
 (defun xterm-mouse--read-event-sequence-1000 ()
-  (list (let ((code (- (read-event) 32)))
+  (let* ((code (- (read-event) 32))
+         (type
           (intern
            ;; For buttons > 3, the release-event looks differently
            ;; (see xc/programs/xterm/button.c, function EditorButton),
@@ -163,19 +167,19 @@ http://invisible-island.net/xterm/ctlseqs/ctlseqs.html)."
                  ((memq code '(8 9 10))
                   (setq xterm-mouse-last (- code 8))
                   (format "M-down-mouse-%d" (- code 7)))
-                 ((= code 11)
-                  (format "M-mouse-%d" (+ 1 (or xterm-mouse-last 0))))
-                 ((= code 3)
-                  ;; For buttons > 5 xterm only reports a
-                  ;; button-release event.  Avoid error by mapping
-                  ;; them all to mouse-1.
-                  (format "mouse-%d" (+ 1 (or xterm-mouse-last 0))))
-                 (t
+                 ((and (= code 11) xterm-mouse-last)
+                  (format "M-mouse-%d" (1+ xterm-mouse-last)))
+                 ((and (= code 3) xterm-mouse-last)
+                  ;; For buttons > 5 xterm only reports a button-release event.
+                  ;; Drop them since they're not usable and can be spurious.
+                  (format "mouse-%d" (1+ xterm-mouse-last)))
+                 ((memq code '(0 1 2))
                   (setq xterm-mouse-last code)
                   (format "down-mouse-%d" (+ 1 code))))))
-        ;; x and y coordinates
-        (max 0 (- (read-event) 33))
-        (max 0 (- (read-event) 33))))
+         (x (- (read-event) 33))
+         (y (- (read-event) 33)))
+    (and type (wholenump x) (wholenump y)
+         (list type x y))))
 
 ;; XTerm's 1006-mode terminal mouse click reporting has the form
 ;; <BUTTON> ; <X> ; <Y> <M or m>, where the button and ordinates are
@@ -222,32 +226,33 @@ which is the \"1006\" extension implemented in Xterm >= 277."
                       ((eq extension 1006)
                        (xterm-mouse--read-event-sequence-1006))
                       (t
-                       (error "Unsupported XTerm mouse protocol"))))
-         (type (nth 0 click))
-         (x    (nth 1 click))
-         (y    (nth 2 click))
-         ;; Emulate timestamp information.  This is accurate enough
-         ;; for default value of mouse-1-click-follows-link (450msec).
-         (timestamp (xterm-mouse-truncate-wrap
-                     (* 1000
-                        (- (float-time)
-                           (or xt-mouse-epoch
-                               (setq xt-mouse-epoch (float-time)))))))
-         (w (window-at x y))
-         (ltrb (window-edges w))
-         (left (nth 0 ltrb))
-         (top (nth 1 ltrb)))
-    (set-terminal-parameter nil 'xterm-mouse-x x)
-    (set-terminal-parameter nil 'xterm-mouse-y y)
-    (setq
-     last-input-event
-     (list type
-           (let ((event (if w
-                            (posn-at-x-y (- x left) (- y top) w t)
-                          (append (list nil 'menu-bar)
-                                  (nthcdr 2 (posn-at-x-y x y))))))
-             (setcar (nthcdr 3 event) timestamp)
-             event)))))
+                       (error "Unsupported XTerm mouse protocol")))))
+    (when click
+      (let* ((type (nth 0 click))
+             (x    (nth 1 click))
+             (y    (nth 2 click))
+             ;; Emulate timestamp information.  This is accurate enough
+             ;; for default value of mouse-1-click-follows-link (450msec).
+             (timestamp (xterm-mouse-truncate-wrap
+                         (* 1000
+                            (- (float-time)
+                               (or xt-mouse-epoch
+                                   (setq xt-mouse-epoch (float-time)))))))
+             (w (window-at x y))
+             (ltrb (window-edges w))
+             (left (nth 0 ltrb))
+             (top (nth 1 ltrb)))
+        (set-terminal-parameter nil 'xterm-mouse-x x)
+        (set-terminal-parameter nil 'xterm-mouse-y y)
+        (setq
+         last-input-event
+         (list type
+               (let ((event (if w
+                                (posn-at-x-y (- x left) (- y top) w t)
+                              (append (list nil 'menu-bar)
+                                      (nthcdr 2 (posn-at-x-y x y))))))
+                 (setcar (nthcdr 3 event) timestamp)
+                 event)))))))
 
 ;;;###autoload
 (define-minor-mode xterm-mouse-mode