Make libraries works with xterm-mouse-mode.

Change calls from 'read-event' to 'read-key' in libraries expecting
mouse events.  Do this only when 'xterm-mouse-mode' is enabled.  That
way those libraries read decoded mouse events instead of the
underlying escape sequence.  Add a parameter to 'read-key' that avoids
running any of the unbound fallbacks in 'read-key-sequence' so the
libraries can read mouse button-down events.

For backward compatibility purposes, the above logic is contained in a
new internal-only function: 'read--potential-mouse-event'.

* doc/lispref/commands.texi (Reading One Event): Document new
parameter to 'read-key'.  Mention that non-character events on
terminals need 'read-key'.
* lisp/subr.el (read-key-full-map): Add new keymap used by 'read-key'.
(read-key): Add new parameter 'fallbacks-disabled' to prevent running
any of the unbound fallbacks normally run by 'read-key-sequence'.
(read--potential-mouse-event): Add new function that calls 'read-key'
or 'read-event' depending on if 'xterm-mouse-mode' is set.
* lisp/foldout.el (foldout-mouse-swallow-events):
* lisp/isearch.el (isearch-pre-command-hook):
* lisp/mouse-drag.el (mouse-drag-throw, mouse-drag-drag):
* lisp/mouse.el (mouse-drag-secondary):
* lisp/ruler-mode.el (ruler-mode-mouse-grab-any-column)
(ruler-mode-mouse-drag-any-column-iteration):
* lisp/strokes.el (strokes-read-stroke, strokes-read-complex-stroke):
* lisp/textmodes/artist.el (artist-mouse-draw-continously)
(artist-mouse-draw-poly, artist-mouse-draw-2points):
* lisp/vc/ediff-wind.el (ediff-get-window-by-clicking):
* lisp/wid-edit.el (widget-button--check-and-call-button)
(widget-button-click): Call 'read--potential-mouse-event' instead of
'read-event'.
* lisp/wid-edit.el (widget-key-sequence-read-event): Call 'read-key'
with 'fallbacks-disabled' set instead of 'read-event'.  Unlike above
changes, this is unconditionally applied so it works for function
keys too.  Apply 'local-function-key-map' instead of
'function-key-map' as that contains the full terminal translations.
* lisp/vc/ediff.el (ediff-windows): Use 'display-mouse-p' to check if
a mouse is available.
* src/lread.c (Fread_event): Recommend 'read-key' in docstring for
'read-event' for non-character events.

1 files changed, 8 insertions, 6 deletions

diff --git a/lisp/wid-edit.el b/lisp/wid-edit.el
index 8b10d71dcb3..7dda04eda21 100644
--- a/lisp/wid-edit.el
+++ b/lisp/wid-edit.el
@@ -1104,7 +1104,7 @@ If nothing was called, return non-nil."
 		  (unless (widget-apply button :mouse-down-action event)
 		    (let ((track-mouse t))
 		      (while (not (widget-button-release-event-p event))
-		        (setq event (read-event))
+                        (setq event (read--potential-mouse-event))
 		        (when (and mouse-1 (mouse-movement-p event))
 			  (push event unread-command-events)
 			  (setq event oevent)
@@ -1169,7 +1169,7 @@ If nothing was called, return non-nil."
 	    (when up
 	      ;; Don't execute up events twice.
 	      (while (not (widget-button-release-event-p event))
-		(setq event (read-event))))
+		(setq event (read--potential-mouse-event))))
 	    (when command
 	      (call-interactively command)))))
     (message "You clicked somewhere weird.")))
@@ -3486,14 +3486,16 @@ It reads a directory name from an editable text field."
   :help-echo "C-q: insert KEY, EVENT, or CODE; RET: enter value"
   :tag "Key sequence")
 
+;; FIXME: Consider combining this with help--read-key-sequence which
+;; can also read double and triple mouse events.
 (defun widget-key-sequence-read-event (ev)
   (interactive (list
 		(let ((inhibit-quit t) quit-flag)
-		  (read-event "Insert KEY, EVENT, or CODE: "))))
+		  (read-key "Insert KEY, EVENT, or CODE: " t))))
   (let ((ev2 (and (memq 'down (event-modifiers ev))
-		  (read-event)))
-	(tr (and (keymapp function-key-map)
-		 (lookup-key function-key-map (vector ev)))))
+		  (read-key nil t)))
+	(tr (and (keymapp local-function-key-map)
+		 (lookup-key local-function-key-map (vector ev)))))
     (when (and (integerp ev)
 	       (or (and (<= ?0 ev) (< ev (+ ?0 (min 10 read-quoted-char-radix))))
 		   (and (<= ?a (downcase ev))