(display-message-or-buffer): New function.

(shell-command-on-region): Use `display-message-or-buffer'.

1 files changed, 68 insertions, 36 deletions

diff --git a/lisp/simple.el b/lisp/simple.el
index 4ef45839d6e..51107e20a29 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -1215,6 +1215,63 @@ specifies the value of ERROR-BUFFER."
             (shell-command-on-region (point) (point) command
                                      output-buffer nil error-buffer)))))))
 
+(defun display-message-or-buffer (message
+                                  &optional buffer-name not-this-window frame)
+  "Display MESSAGE in the echo area if possible, otherwise in a pop-up buffer.
+MESSAGE may be either a string or a buffer.
+
+A buffer is displayed using `display-buffer' if MESSAGE is too long for
+the maximum height of the echo area, as defined by `max-mini-window-height'.
+
+If MESSAGE is a string, then the optional argument BUFFER-NAME is the
+name of the buffer used to display it in the case where a pop-up buffer
+is used, defaulting to `*Message*'.  In the case where MESSAGE is a
+string and it is displayed in the echo area, it is not specified whether
+the contents are inserted into the buffer anyway.
+
+Optional arguments NOT-THIS-WINDOW and FRAME are as for `display-buffer',
+and only used if a buffer is displayed."
+  (cond ((and (stringp message) (not (string-match "\n" message)))
+         ;; Trivial case where we can use the echo area
+         (message "%s" message))
+        ((and (stringp message)
+              (= (string-match "\n" message) (1- (length message))))
+         ;; Trivial case where we can just remove single trailing newline
+         (message "%s" (substring message 0 (1- (length message)))))
+        (t
+         ;; General case
+         (with-current-buffer
+             (if (bufferp message)
+                 message
+               (get-buffer-create (or buffer-name "*Message*")))
+
+           (unless (bufferp message)
+             (erase-buffer)
+             (insert message))
+
+           (let ((lines
+                  (if (= (buffer-size) 0)
+                      0
+                    (count-lines (point-min) (point-max)))))
+             (cond ((or (<= lines 1)
+                        (<= lines
+                            (cond ((floatp max-mini-window-height)
+                                   (* (frame-height) max-mini-window-height))
+                                  ((integerp max-mini-window-height)
+                                   max-mini-window-height)
+                                  (t
+                                   1))))
+                    ;; Echo area
+                    (goto-char (point-max))
+                    (when (bolp)
+                      (backward-char 1))
+                    (message "%s" (buffer-substring (point-min) (point))))
+                   (t
+                    ;; Buffer
+                    (goto-char (point-min))
+                    (display-buffer message not-this-window frame))))))))
+
+
 ;; We have a sentinel to prevent insertion of a termination message
 ;; in the buffer itself.
 (defun shell-command-sentinel (process signal)
@@ -1345,42 +1402,17 @@ specifies the value of ERROR-BUFFER."
                                          nil shell-command-switch command)))
           (setq success (and exit-status (equal 0 exit-status)))
           ;; Report the amount of output.
-          (let ((lines (save-excursion
-                         (set-buffer buffer)
-                         (if (= (buffer-size) 0)
-                             0
-                           (count-lines (point-min) (point-max))))))
-            (cond ((= lines 0)
-                   (if (and error-file
-                            (< 0 (nth 7 (file-attributes error-file))))
-                       (message "(Shell command %sed with some error output)"
-                                (if (equal 0 exit-status)
-                                    "succeed"
-                                  "fail"))
-                     (message "(Shell command %sed with no output)"
-                              (if (equal 0 exit-status)
-                                  "succeed"
-                                "fail")))
-                   (kill-buffer buffer))
-                  ((or (= lines 1)
-                       (<= lines
-                           (cond ((floatp max-mini-window-height)
-                                  (* (frame-height) max-mini-window-height))
-                                 ((integerp max-mini-window-height)
-                                  max-mini-window-height)
-                                 (t
-                                  1))))
-                   (message "%s"
-                            (with-current-buffer buffer
-                              (goto-char (point-max))
-                              (when (bolp)
-                                (backward-char 1))
-                              (buffer-substring (point-min) (point)))))
-                  (t
-                   (save-excursion
-                     (set-buffer buffer)
-                     (goto-char (point-min)))
-                   (display-buffer buffer)))))))
+          (if (with-current-buffer buffer (> (point-max) (point-min)))
+              ;; There's some output, display it
+              (display-message-or-buffer buffer)
+            ;; No output; error?
+            (message (if (and error-file
+                              (< 0 (nth 7 (file-attributes error-file))))
+                         "(Shell command %sed with some error output)"
+                       "(Shell command %sed with no output)")
+                     (if (equal 0 exit-status) "succeed" "fail"))
+            (kill-buffer buffer)))))
+
     (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)