;;; x-win.el --- parse switches controlling interface with X window system
-;; Copyright (C) 1993, 1994, 2001 Free Software Foundation, Inc.
+;; Copyright (C) 1993, 1994, 2001, 2002 Free Software Foundation, Inc.
;; Author: FSF
;; Keywords: terminals
;;; We keep track of the last text selected here, so we can check the
;;; current selection against it, and avoid passing back our own text
-;;; from x-cut-buffer-or-selection-value.
-(defvar x-last-selected-text nil)
+;;; from x-cut-buffer-or-selection-value. We track all three
+;;; seperately in case another X application only sets one of them
+;;; (say the the cut buffer) we aren't fooled by the PRIMARY or
+;;; CLIPBOARD selection staying the same.
+(defvar x-last-selected-text-clipboard nil
+ "The value of the CLIPBOARD X selection last time we selected or
+pasted text.")
+(defvar x-last-selected-text-primary nil
+ "The value of the PRIMARY X selection last time we selected or
+pasted text.")
+(defvar x-last-selected-text-cut nil
+ "The vaue of the X cut buffer last time we selected or
+pasted text.")
;;; It is said that overlarge strings are slow to put into the cut buffer.
;;; Note this value is overridden below.
(defun x-select-text (text &optional push)
;; Don't send the cut buffer too much text.
;; It becomes slow, and if really big it causes errors.
- (if (< (length text) x-cut-buffer-max)
+ (cond ((>= (length text) x-cut-buffer-max)
+ (x-set-cut-buffer "" push)
+ (setq x-last-selected-text-cut ""))
+ (t
(x-set-cut-buffer text push)
- (x-set-cut-buffer "" push))
+ (setq x-last-selected-text-cut text)))
(x-set-selection 'PRIMARY text)
- (if x-select-enable-clipboard
- (x-set-selection 'CLIPBOARD text))
- (setq x-last-selected-text text))
+ (setq x-last-selected-text-primary text)
+ (when x-select-enable-clipboard
+ (x-set-selection 'CLIPBOARD text)
+ (setq x-last-selected-text-clipboard text))
+ )
;;; Return the value of the current X selection.
-;;; Consult the selection, then the cut buffer. Treat empty strings
+;;; Consult the selection, and the cut buffer. Treat empty strings
;;; as if they were unset.
;;; If this function is called twice and finds the same text,
;;; it returns nil the second time. This is so that a single
;;; selection won't be added to the kill ring over and over.
(defun x-cut-buffer-or-selection-value ()
- (let (text)
+ (let (clip-text primary-text cut-text)
(when x-select-enable-clipboard
- (if (null text)
+ ;; Don't die if x-get-selection signals an error.
+ (if (null clip-text)
(condition-case c
- (setq text (x-get-selection 'CLIPBOARD 'COMPOUND_TEXT))
+ (setq clip-text (x-get-selection 'CLIPBOARD 'COMPOUND_TEXT))
(error nil)))
- (if (null text)
+ (if (null clip-text)
(condition-case c
- (setq text (x-get-selection 'CLIPBOARD 'STRING))
+ (setq clip-text (x-get-selection 'CLIPBOARD 'STRING))
(error nil)))
- (if (string= text "") (setq text nil)))
+ (if (string= clip-text "") (setq clip-text nil))
+
+ ;; Check the CLIPBOARD selection for 'newness', is it different
+ ;; from what we remebered them to be last time we did a
+ ;; cut/paste operation.
+ (setq clip-text
+ (cond;; check clipboard
+ ((or (not clip-text) (string= clip-text ""))
+ (setq x-last-selected-text-clipboard nil))
+ ((eq clip-text x-last-selected-text-clipboard) nil)
+ ((string= clip-text x-last-selected-text-clipboard)
+ ;; Record the newer string,
+ ;; so subsequent calls can use the `eq' test.
+ (setq x-last-selected-text-clipboard clip-text)
+ nil)
+ (t
+ (setq x-last-selected-text-clipboard clip-text))))
+ )
;; Don't die if x-get-selection signals an error.
- (if (null text)
+ (if (null primary-text)
(condition-case c
- (setq text (x-get-selection 'PRIMARY 'COMPOUND_TEXT))
+ (setq primary-text (x-get-selection 'PRIMARY 'COMPOUND_TEXT))
(error nil)))
- (if (null text)
+ (if (null primary-text)
(condition-case c
- (setq text (x-get-selection 'PRIMARY 'STRING))
+ (setq primary-text (x-get-selection 'PRIMARY 'STRING))
(error nil)))
- (if (string= text "") (setq text nil))
-
- (or text (setq text (x-get-cut-buffer 0)))
- (if (string= text "") (setq text nil))
-
- (cond
- ((not text) nil)
- ((eq text x-last-selected-text) nil)
- ((string= text x-last-selected-text)
- ;; Record the newer string, so subsequent calls can use the `eq' test.
- (setq x-last-selected-text text)
+ ;; Check the PRIMARY selection for 'newness', is it different
+ ;; from what we remebered them to be last time we did a
+ ;; cut/paste operation.
+ (setq primary-text
+ (cond;; check primary selection
+ ((or (not primary-text) (string= primary-text ""))
+ (setq x-last-selected-text-primary nil))
+ ((eq primary-text x-last-selected-text-primary) nil)
+ ((string= primary-text x-last-selected-text-primary)
+ ;; Record the newer string,
+ ;; so subsequent calls can use the `eq' test.
+ (setq x-last-selected-text-primary primary-text)
+ nil)
+ (t
+ (setq x-last-selected-text-primary primary-text))))
+
+ (setq cut-text (x-get-cut-buffer 0))
+
+ ;; Check the x cut buffer for 'newness', is it different
+ ;; from what we remebered them to be last time we did a
+ ;; cut/paste operation.
+ (setq cut-text
+ (cond;; check primary selection
+ ((or (not cut-text) (string= cut-text ""))
+ (setq x-last-selected-text-cut nil))
+ ((eq cut-text x-last-selected-text-cut) nil)
+ ((string= cut-text x-last-selected-text-cut)
+ ;; Record the newer string,
+ ;; so subsequent calls can use the `eq' test.
+ (setq x-last-selected-text-cut cut-text)
nil)
(t
- (setq x-last-selected-text text)))))
+ (setq x-last-selected-text-cut cut-text))))
+
+ ;; At this point we have recorded the current values for the
+ ;; selection from clipboard (if we are supposed to) primary,
+ ;; and cut buffer. So return the first one that has changed
+ ;; (which is the first non-null one).
+ ;;
+ ;; NOTE: There will be cases where more than one of these has
+ ;; changed and the new values differ. This indicates that
+ ;; something like the following has happened since the last time
+ ;; we looked at the selections: Application X set all the
+ ;; selections, then Application Y set only one or two of them (say
+ ;; just the cut-buffer). In this case since we don't have
+ ;; timestamps there is no way to know what the 'correct' value to
+ ;; return is. The nice thing to do would be to tell the user we
+ ;; saw multiple possible selections and ask the user which was the
+ ;; one they wanted.
+ ;; This code is still a big improvement because now the user can
+ ;; futz with the current selection and get emacs to pay attention
+ ;; to the cut buffer again (previously as soon as clipboard or
+ ;; primary had been set the cut buffer would essentially never be
+ ;; checked again).
+ (or clip-text primary-text cut-text)
+ ))
\f
;;; Do the actual X Windows setup here; the above code just defines