Minor refactoring in shell-command

* lisp/simple.el (shell-command): Use call-process-shell-command,
start-process-shell-command, and file-attribute-size. (bug#30280).

1 files changed, 28 insertions, 30 deletions

diff --git a/lisp/simple.el b/lisp/simple.el
index a0a6898e17f..57e70a8d153 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3400,6 +3400,8 @@ a shell (with its need to quote arguments)."
     (setq command (concat command " &")))
   (shell-command command output-buffer error-buffer))
 
+(declare-function comint-output-filter "comint" (process string))
+
 (defun shell-command (command &optional output-buffer error-buffer)
   "Execute string COMMAND in inferior shell; display output, if any.
 With prefix argument, insert the COMMAND's output at point.
@@ -3477,12 +3479,11 @@ impose the use of a shell (with its need to quote arguments)."
                (not (or (bufferp output-buffer)  (stringp output-buffer))))
           ;; Output goes in current buffer.
           (let ((error-file
-                 (if error-buffer
-                     (make-temp-file
-                      (expand-file-name "scor"
-                                        (or small-temporary-file-directory
-                                            temporary-file-directory)))
-                   nil)))
+                 (and error-buffer
+                      (make-temp-file
+                       (expand-file-name "scor"
+                                         (or small-temporary-file-directory
+                                             temporary-file-directory))))))
             (barf-if-buffer-read-only)
             (push-mark nil t)
             ;; We do not use -f for csh; we will not support broken use of
@@ -3490,24 +3491,22 @@ impose the use of a shell (with its need to quote arguments)."
             ;; "if ($?prompt) exit" before things which are not useful
             ;; non-interactively.  Besides, if someone wants their other
             ;; aliases for shell commands then they can still have them.
-            (call-process shell-file-name nil
-                          (if error-file
-                              (list t error-file)
-                            t)
-                          nil shell-command-switch command)
+            (call-process-shell-command command nil (if error-file
+                                                        (list t error-file)
+                                                      t))
             (when (and error-file (file-exists-p error-file))
-              (if (< 0 (nth 7 (file-attributes error-file)))
-                  (with-current-buffer (get-buffer-create error-buffer)
-                    (let ((pos-from-end (- (point-max) (point))))
-                      (or (bobp)
-                          (insert "\f\n"))
-                      ;; Do no formatting while reading error file,
-                      ;; because that can run a shell command, and we
-                      ;; don't want that to cause an infinite recursion.
-                      (format-insert-file error-file nil)
-                      ;; Put point after the inserted errors.
-                      (goto-char (- (point-max) pos-from-end)))
-                    (display-buffer (current-buffer))))
+              (when (< 0 (file-attribute-size (file-attributes error-file)))
+                (with-current-buffer (get-buffer-create error-buffer)
+                  (let ((pos-from-end (- (point-max) (point))))
+                    (or (bobp)
+                        (insert "\f\n"))
+                    ;; Do no formatting while reading error file,
+                    ;; because that can run a shell command, and we
+                    ;; don't want that to cause an infinite recursion.
+                    (format-insert-file error-file nil)
+                    ;; Put point after the inserted errors.
+                    (goto-char (- (point-max) pos-from-end)))
+                  (display-buffer (current-buffer))))
               (delete-file error-file))
             ;; This is like exchange-point-and-mark, but doesn't
             ;; activate the mark.  It is cleaner to avoid activation,
@@ -3526,12 +3525,11 @@ impose the use of a shell (with its need to quote arguments)."
               (let* ((buffer (get-buffer-create
                               (or output-buffer "*Async Shell Command*")))
                      (bname (buffer-name buffer))
-                     (directory default-directory)
-                     proc)
+                     (proc (get-buffer-process buffer))
+                     (directory default-directory))
                 ;; Remove the ampersand.
                 (setq command (substring command 0 (match-beginning 0)))
                 ;; Ask the user what to do with already running process.
-                (setq proc (get-buffer-process buffer))
                 (when proc
                   (cond
                    ((eq async-shell-command-buffer 'confirm-kill-process)
@@ -3563,14 +3561,14 @@ impose the use of a shell (with its need to quote arguments)."
                 (with-current-buffer buffer
                   (shell-command--save-pos-or-erase)
                   (setq default-directory directory)
-                  (setq proc (start-process "Shell" buffer shell-file-name
-                                            shell-command-switch command))
+                  (setq proc
+                        (start-process-shell-command "Shell" buffer command))
                   (setq mode-line-process '(":%s"))
                   (require 'shell) (shell-mode)
-                  (set-process-sentinel proc 'shell-command-sentinel)
+                  (set-process-sentinel proc #'shell-command-sentinel)
                   ;; Use the comint filter for proper handling of
                   ;; carriage motion (see comint-inhibit-carriage-motion).
-                  (set-process-filter proc 'comint-output-filter)
+                  (set-process-filter proc #'comint-output-filter)
                   (if async-shell-command-display-buffer
                       ;; Display buffer immediately.
                       (display-buffer buffer '(nil (allow-no-window . t)))