From 683efb8de5ac3a2ba5ecc073d8c912ec6a61191d Mon Sep 17 00:00:00 2001 From: Spencer Baugh Date: Thu, 21 Sep 2023 21:35:50 -0400 Subject: [PATCH] Add 'server-eval-args-left' to server.el Passing arbitrary arguments to functions through "emacsclient --eval" sometimes requires complicated escaping to avoid them being parsed as Lisp (as seen in emacsclient-mail.desktop before this change). The new variable 'server-eval-args-left' allows access to the arguments before they are parsed as Lisp. By removing arguments from the variable before they're parsed, a snippet of Lisp can consume arguments, as in emacsclient-mail.desktop. org-protocol might be able to use this as well, which might allow it to drop its current advice on server-visit-files. * etc/emacsclient-mail.desktop: Use 'server-eval-args-left'. * lisp/server.el (server-eval-args-left): New variable. (server-process-filter, server-execute): Make '-eval' arguments available through 'server-eval-args-left'. * lisp/startup.el (argv): Mention 'server-eval-args-left' in docstring. * etc/NEWS: Announce 'server-eval-args-left'. * doc/emacs/misc.texi (emacsclient Options): Document 'server-eval-args-left'. (Bug#65902) --- doc/emacs/misc.texi | 9 +++++++++ etc/NEWS | 10 ++++++++++ etc/emacsclient-mail.desktop | 7 ++----- lisp/server.el | 27 ++++++++++++++++++++------- lisp/startup.el | 5 ++++- 5 files changed, 45 insertions(+), 13 deletions(-) diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi index d7168fa1ca0..9c7c5dcd5da 100644 --- a/doc/emacs/misc.texi +++ b/doc/emacs/misc.texi @@ -2078,6 +2078,15 @@ files. When this option is given, the arguments to @command{emacsclient} are interpreted as a list of expressions to evaluate, @emph{not} as a list of files to visit. +@vindex server-eval-args-left +If you have arbitrary data which you want to provide as input to one +of your expressions, you can pass the data as another argument to +@command{emacsclient} and use @var{server-eval-args-left} in the +expression to access the data. Be careful to have your expression +remove the data from @var{server-eval-args-left} regardless of whether +your code succeeds, such as by using @code{pop}, otherwise Emacs will +attempt to evaluate the data as a Lisp expression. + @item -f @var{server-file} @itemx --server-file=@var{server-file} Specify a server file (@pxref{TCP Emacs server}) for connecting to an diff --git a/etc/NEWS b/etc/NEWS index 8ae7b89e830..84a03495798 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -233,6 +233,16 @@ to enter the file you want to modify. It can be used to customize the look of the appointment notification displayed on the mode line when 'appt-display-mode-line' is non-nil. +** Emacs Server and Client + +--- +*** 'server-eval-args-left' can be used to pop subsequent eval args +When '--eval' is passed to emacsclient and Emacs is evaluating each +argument, this variable is set to those which have not yet been +evaluated. It can be used to 'pop' arguments to prevent them from +being evaluated, which is useful when those arguments contain +arbitrary data. + * Editing Changes in Emacs 30.1 diff --git a/etc/emacsclient-mail.desktop b/etc/emacsclient-mail.desktop index 0a2420ddead..4f7f00ebefd 100644 --- a/etc/emacsclient-mail.desktop +++ b/etc/emacsclient-mail.desktop @@ -1,10 +1,7 @@ [Desktop Entry] Categories=Network;Email; Comment=GNU Emacs is an extensible, customizable text editor - and more -# We want to pass the following commands to the shell wrapper: -# u=$(echo "$1" | sed 's/[\"]/\\&/g'); exec emacsclient --alternate-editor= --display="$DISPLAY" --eval "(message-mailto \"$u\")" -# Special chars '"', '$', and '\' must be escaped as '\\"', '\\$', and '\\\\'. -Exec=sh -c "u=\\$(echo \\"\\$1\\" | sed 's/[\\\\\\"]/\\\\\\\\&/g'); exec emacsclient --alternate-editor= --display=\\"\\$DISPLAY\\" --eval \\"(message-mailto \\\\\\"\\$u\\\\\\")\\"" sh %u +Exec=emacsclient --alternate-editor= --eval "(message-mailto (pop server-eval-args-left))" %u Icon=emacs Name=Emacs (Mail, Client) MimeType=x-scheme-handler/mailto; @@ -16,7 +13,7 @@ Actions=new-window;new-instance; [Desktop Action new-window] Name=New Window -Exec=sh -c "u=\\$(echo \\"\\$1\\" | sed 's/[\\\\\\"]/\\\\\\\\&/g'); exec emacsclient --alternate-editor= --create-frame --eval \\"(message-mailto \\\\\\"\\$u\\\\\\")\\"" sh %u +Exec=emacsclient --alternate-editor= --create-frame --eval "(message-mailto (pop server-eval-args-left))" %u [Desktop Action new-instance] Name=New Instance diff --git a/lisp/server.el b/lisp/server.el index ce68e9aebc9..a2671165bfc 100644 --- a/lisp/server.el +++ b/lisp/server.el @@ -1199,6 +1199,7 @@ The following commands are accepted by the client: parent-id ; Window ID for XEmbed dontkill ; t if client should not be killed. commands + evalexprs dir use-current-frame frame-parameters ;parameters for newly created frame @@ -1332,8 +1333,7 @@ The following commands are accepted by the client: (let ((expr (pop args-left))) (if coding-system (setq expr (decode-coding-string expr coding-system))) - (push (lambda () (server-eval-and-print expr proc)) - commands) + (push expr evalexprs) (setq filepos nil))) ;; -env NAME=VALUE: An environment variable. @@ -1358,7 +1358,7 @@ The following commands are accepted by the client: ;; arguments, use an existing frame. (and nowait (not (eq tty-name 'window-system)) - (or files commands) + (or files commands evalexprs) (setq use-current-frame t)) (setq frame @@ -1407,7 +1407,7 @@ The following commands are accepted by the client: (let ((default-directory (if (and dir (file-directory-p dir)) dir default-directory))) - (server-execute proc files nowait commands + (server-execute proc files nowait commands evalexprs dontkill frame tty-name))))) (when (or frame files) @@ -1417,22 +1417,35 @@ The following commands are accepted by the client: ;; condition-case (t (server-return-error proc err)))) -(defun server-execute (proc files nowait commands dontkill frame tty-name) +(defvar server-eval-args-left nil + "List of eval args not yet processed. + +Adding or removing strings from this variable while the Emacs +server is processing a series of eval requests will affect what +Emacs evaluates. + +See also `argv' for a similar variable which works for +invocations of \"emacs\".") + +(defun server-execute (proc files nowait commands evalexprs dontkill frame tty-name) ;; This is run from timers and process-filters, i.e. "asynchronously". ;; But w.r.t the user, this is not really asynchronous since the timer ;; is run after 0s and the process-filter is run in response to the ;; user running `emacsclient'. So it is OK to override the - ;; inhibit-quit flag, which is good since `commands' (as well as + ;; inhibit-quit flag, which is good since `evalexprs' (as well as ;; find-file-noselect via the major-mode) can run arbitrary code, ;; including code that needs to wait. (with-local-quit (condition-case err (let ((buffers (server-visit-files files proc nowait))) (mapc 'funcall (nreverse commands)) + (let ((server-eval-args-left (nreverse evalexprs))) + (while server-eval-args-left + (server-eval-and-print (pop server-eval-args-left) proc))) ;; If we were told only to open a new client, obey ;; `initial-buffer-choice' if it specifies a file ;; or a function. - (unless (or files commands) + (unless (or files commands evalexprs) (let ((buf (cond ((stringp initial-buffer-choice) (find-file-noselect initial-buffer-choice)) diff --git a/lisp/startup.el b/lisp/startup.el index 6329e3ea8d0..37843eab176 100644 --- a/lisp/startup.el +++ b/lisp/startup.el @@ -120,7 +120,10 @@ the remaining command-line args are in the variable `command-line-args-left'.") "List of command-line args not yet processed. This is a convenience alias, so that one can write (pop argv) inside of --eval command line arguments in order to access -following arguments.")) +following arguments. + +See also `server-eval-args-left' for a similar variable which +works for invocations of \"emacsclient --eval\".")) (internal-make-var-non-special 'argv) (defvar command-line-args-left nil -- 2.39.2