diff --git a/lisp/menu-bar.el b/lisp/menu-bar.el index ab64928fe76..d8c8c760f78 100644 --- a/lisp/menu-bar.el +++ b/lisp/menu-bar.el @@ -606,7 +606,8 @@ "Insert the clipboard contents, or the last stretch of killed text." (interactive "*") (let ((select-enable-clipboard t) - ;; Ensure that we defeat the DWIM login in `gui-selection-value'. + ;; Ensure that we defeat the DWIM logic in `gui-selection-value' + ;; (i.e., that gui--clipboard-selection-unchanged-p returns nil). (gui--last-selected-text-clipboard nil)) (yank))) diff --git a/lisp/select.el b/lisp/select.el index c352a482616..0b51f01cc58 100644 --- a/lisp/select.el +++ b/lisp/select.el @@ -25,9 +25,10 @@ ;; Based partially on earlier release by Lucid. ;; The functionality here is divided in two parts: -;; - Low-level: gui-get-selection, gui-set-selection, gui-selection-owner-p, -;; gui-selection-exists-p are the backend-dependent functions meant to access -;; various kinds of selections (CLIPBOARD, PRIMARY, SECONDARY). +;; - Low-level: gui-backend-get-selection, gui-backend-set-selection, +;; gui-backend-selection-owner-p, gui-backend-selection-exists-p are +;; the backend-dependent functions meant to access various kinds of +;; selections (CLIPBOARD, PRIMARY, SECONDARY). ;; - Higher-level: gui-select-text and gui-selection-value go together to ;; access the general notion of "GUI selection" for interoperation with other ;; applications. This can use either the clipboard or the primary selection, @@ -108,9 +109,10 @@ E.g. it doesn't exist under MS-Windows." :group 'killing :version "25.1") -;; 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 gui-selection-value. We track both +;; We keep track of the last selection here, so we can check the +;; current selection against it, and avoid passing back with +;; gui-selection-value the same text we previously killed or +;; yanked. We track both ;; separately in case another X application only sets one of them ;; we aren't fooled by the PRIMARY or CLIPBOARD selection staying the same. @@ -119,22 +121,68 @@ E.g. it doesn't exist under MS-Windows." (defvar gui--last-selected-text-primary nil "The value of the PRIMARY selection last seen.") +(defvar gui--last-selection-timestamp-clipboard nil + "The timestamp of the CLIPBOARD selection last seen.") +(defvar gui--last-selection-timestamp-primary nil + "The timestamp of the PRIMARY selection last seen.") + +(defun gui--set-last-clipboard-selection (text) + "Save last clipboard selection. +Save the selected text, passed as argument, and for window +systems that support it, save the selection timestamp too." + (setq gui--last-selected-text-clipboard text) + (when (eq window-system 'x) + (setq gui--last-selection-timestamp-clipboard + (gui-backend-get-selection 'CLIPBOARD 'TIMESTAMP)))) + +(defun gui--set-last-primary-selection (text) + "Save last primary selection. +Save the selected text, passed as argument, and for window +systems that support it, save the selection timestamp too." + (setq gui--last-selected-text-primary text) + (when (eq window-system 'x) + (setq gui--last-selection-timestamp-primary + (gui-backend-get-selection 'PRIMARY 'TIMESTAMP)))) + +(defun gui--clipboard-selection-unchanged-p (text) + "Check whether the clipboard selection has changed. +Compare the selection text, passed as argument, with the text +from the last saved selection. For window systems that support +it, compare the selection timestamp too." + (and + (equal text gui--last-selected-text-clipboard) + (or (not (eq window-system 'x)) + (eq gui--last-selection-timestamp-clipboard + (gui-backend-get-selection 'CLIPBOARD 'TIMESTAMP))))) + +(defun gui--primary-selection-unchanged-p (text) + "Check whether the primary selection has changed. +Compare the selection text, passed as argument, with the text +from the last saved selection. For window systems that support +it, compare the selection timestamp too." + (and + (equal text gui--last-selected-text-primary) + (or (not (eq window-system 'x)) + (eq gui--last-selection-timestamp-primary + (gui-backend-get-selection 'PRIMARY 'TIMESTAMP))))) + + (defun gui-select-text (text) "Select TEXT, a string, according to the window system. -if `select-enable-clipboard' is non-nil, copy TEXT to the system's clipboard. +If `select-enable-clipboard' is non-nil, copy TEXT to the system's clipboard. If `select-enable-primary' is non-nil, put TEXT in the primary selection. MS-Windows does not have a \"primary\" selection." (when select-enable-primary (gui-set-selection 'PRIMARY text) - (setq gui--last-selected-text-primary text)) + (gui--set-last-primary-selection text)) (when select-enable-clipboard ;; When cutting, the selection is cleared and PRIMARY ;; set to the empty string. Prevent that, PRIMARY ;; should not be reset by cut (Bug#16382). (setq saved-region-selection text) (gui-set-selection 'CLIPBOARD text) - (setq gui--last-selected-text-clipboard text))) + (gui--set-last-clipboard-selection text))) (define-obsolete-function-alias 'x-select-text 'gui-select-text "25.1") (defcustom x-select-request-type nil @@ -175,6 +223,7 @@ decoded. If `gui-get-selection' signals an error, return nil." ;; some other window systems. (memq window-system '(x haiku)) (eq type 'CLIPBOARD) + ;; Should we unify this with gui--clipboard-selection-unchanged-p? (gui-backend-selection-owner-p type)) (let ((request-type (if (memq window-system '(x pgtk haiku)) (or x-select-request-type @@ -197,19 +246,17 @@ decoded. If `gui-get-selection' signals an error, return nil." (let ((text (gui--selection-value-internal 'CLIPBOARD))) (when (string= text "") (setq text nil)) - ;; When `select-enable-clipboard' is non-nil, - ;; killing/copying text (with, say, `C-w') will push the - ;; text to the clipboard (and store it in - ;; `gui--last-selected-text-clipboard'). We check - ;; whether the text on the clipboard is identical to this - ;; text, and if so, we report that the clipboard is - ;; empty. See (bug#27442) for further discussion about - ;; this DWIM action, and possible ways to make this check - ;; less fragile, if so desired. - (prog1 - (unless (equal text gui--last-selected-text-clipboard) - text) - (setq gui--last-selected-text-clipboard text))))) + ;; Check the CLIPBOARD selection for 'newness', i.e., + ;; whether it is different from the last time we did a + ;; yank operation or whether it was set by Emacs itself + ;; with a kill operation, since in both cases the text + ;; will already be in the kill ring. See (bug#27442) and + ;; (bug#53894) for further discussion about this DWIM + ;; action, and possible ways to make this check less + ;; fragile, if so desired. + (unless (gui--clipboard-selection-unchanged-p text) + (gui--set-last-clipboard-selection text) + text)))) (primary-text (when select-enable-primary (let ((text (gui--selection-value-internal 'PRIMARY))) @@ -217,10 +264,9 @@ decoded. If `gui-get-selection' signals an error, return nil." ;; Check the PRIMARY selection for 'newness', is it different ;; from what we remembered them to be last time we did a ;; cut/paste operation. - (prog1 - (unless (equal text gui--last-selected-text-primary) - text) - (setq gui--last-selected-text-primary text)))))) + (unless (gui--primary-selection-unchanged-p text) + (gui--set-last-primary-selection text) + text))))) ;; As we have done one selection, clear this now. (setq next-selection-coding-system nil) @@ -235,11 +281,11 @@ decoded. If `gui-get-selection' signals an error, return nil." ;; 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 of them. - ;; 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. + ;; In this case, for systems that support selection timestamps, we + ;; could return the newer. For systems that don't, 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. (or clip-text primary-text) )) diff --git a/lisp/term/pc-win.el b/lisp/term/pc-win.el index 327d51f2759..514267a52d6 100644 --- a/lisp/term/pc-win.el +++ b/lisp/term/pc-win.el @@ -246,6 +246,14 @@ Consult the selection. Treat empty strings as if they were unset." ;; if it does not exist, or exists and compares ;; equal with the last text we've put into the ;; Windows clipboard. + ;; NOTE: that variable is actually the last text any program + ;; (not just Emacs) has put into the windows clipboard (up + ;; until the last time Emacs read or set the clipboard), so + ;; it's not suitable for checking actual selection + ;; ownership. This should not result in a bug for the current + ;; uses of gui-backend-selection-owner however, since they + ;; don't actually care about selection ownership, but about + ;; the selected text having changed. (cond ((not text) t) ((equal text gui--last-selected-text-clipboard) text)