Revert mml-generate-mime-1 (bug#27141)

* lisp/gnus/mml.el (mml-generate-mime-1): Reverted to emacs-25 version
with slight modernizations (bug#27141).

diff --git a/lisp/gnus/mml.el b/lisp/gnus/mml.el
index 3a31349d378c2e41a76614a7f578eb96ca341b60..ce28607a04a349dc03050a916fb2be0157227ac2 100644 (file)
--- a/lisp/gnus/mml.el
+++ b/lisp/gnus/mml.el
@@ -606,38 +606,28 @@ be \"related\" or \"alternate\"."
                                   (intern (downcase charset))))))
          (if (and (not raw)
                   (member (car (split-string type "/")) '("text" "message")))
-             ;; We have a text-like MIME part, so we need to do
-             ;; charset encoding.
              (progn
                (with-temp-buffer
-                 (set-buffer-multibyte nil)
-                 ;; First insert the data into the buffer.
-                 (if  (and filename
-                           (not (equal (cdr (assq 'nofile cont)) "yes")))
-                     (mm-insert-file-contents filename)
-                   (insert
-                    (with-temp-buffer
-                      (cond
-                       ((cdr (assq 'buffer cont))
-                        (insert-buffer-substring (cdr (assq 'buffer cont))))
-                       ((eq 'mml (car cont))
-                        (insert (cdr (assq 'contents cont))))
-                       (t
-                        (insert (cdr (assq 'contents cont)))
-                        ;; Remove quotes from quoted tags.
-                        (goto-char (point-min))
-                        (while (re-search-forward
-                                "<#!+/?\\(part\\|multipart\\|external\\|mml\\|secure\\)"
-                                nil t)
-                          (delete-region (+ (match-beginning 0) 2)
-                                         (+ (match-beginning 0) 3)))))
-                      (setq charset
-                            (mm-coding-system-to-mime-charset
-                             (detect-coding-region
-                              (point-min) (point-max) t)))
-                      (encode-coding-region (point-min) (point-max)
-                                            charset)
-                      (buffer-string))))
+                 (cond
+                  ((cdr (assq 'buffer cont))
+                   (insert-buffer-substring (cdr (assq 'buffer cont))))
+                  ((and filename
+                        (not (equal (cdr (assq 'nofile cont)) "yes")))
+                   (let ((coding-system-for-read coding))
+                     (mm-insert-file-contents filename)))
+                  ((eq 'mml (car cont))
+                   (insert (cdr (assq 'contents cont))))
+                  (t
+                   (save-restriction
+                     (narrow-to-region (point) (point))
+                     (insert (cdr (assq 'contents cont)))
+                     ;; Remove quotes from quoted tags.
+                     (goto-char (point-min))
+                     (while (re-search-forward
+                             "<#!+/?\\(part\\|multipart\\|external\\|mml\\|secure\\)"
+                             nil t)
+                       (delete-region (+ (match-beginning 0) 2)
+                                      (+ (match-beginning 0) 3))))))
                  (cond
                   ((eq (car cont) 'mml)
                    (let ((mml-boundary (mml-compute-boundary cont))
@@ -665,7 +655,7 @@ be \"related\" or \"alternate\"."
                    ;; actually are hard newlines in the text.
                    (let (use-hard-newlines)
                      (when (and mml-enable-flowed
-                                 (string= type "text/plain")
+                                (string= type "text/plain")
                                 (not (string= (cdr (assq 'sign cont)) "pgp"))
                                 (or (null (assq 'format cont))
                                     (string= (cdr (assq 'format cont))
@@ -678,14 +668,13 @@ be \"related\" or \"alternate\"."
                        ;; insert a "; format=flowed" string unless the
                        ;; user has already specified it.
                        (setq flowed (null (assq 'format cont)))))
-                   (unless charset
-                     (setq charset
-                           ;; Prefer `utf-8' for text/calendar parts.
-                           (if (string= type "text/calendar")
-                               'utf-8
-                             (mm-coding-system-to-mime-charset
-                              (detect-coding-region
-                               (point-min) (point-max) t)))))
+                   ;; Prefer `utf-8' for text/calendar parts.
+                   (if (or charset
+                           (not (string= type "text/calendar")))
+                       (setq charset (mm-encode-body charset))
+                     (let ((mm-coding-system-priorities
+                            (cons 'utf-8 mm-coding-system-priorities)))
+                       (setq charset (mm-encode-body))))
                    (setq encoding (mm-body-encoding
                                    charset (cdr (assq 'encoding cont))))))
                  (setq coded (buffer-string)))
@@ -696,26 +685,33 @@ be \"related\" or \"alternate\"."
              (set-buffer-multibyte nil)
              (cond
               ((cdr (assq 'buffer cont))
-               (insert (string-as-unibyte
-                        (with-current-buffer (cdr (assq 'buffer cont))
-                          (buffer-string)))))
+               ;; multibyte string that inserted to a unibyte buffer
+               ;; will be converted to the unibyte version safely.
+               (insert (with-current-buffer (cdr (assq 'buffer cont))
+                         (buffer-string))))
               ((and filename
                     (not (equal (cdr (assq 'nofile cont)) "yes")))
                (let ((coding-system-for-read mm-binary-coding-system))
-                 (mm-insert-file-contents filename nil nil nil nil t)))
+                 (mm-insert-file-contents filename nil nil nil nil t))
+               (unless charset
+                 (setq charset (mm-coding-system-to-mime-charset
+                                (mm-find-buffer-file-coding-system
+                                 filename)))))
               (t
                (let ((contents (cdr (assq 'contents cont))))
-                 (if (multibyte-string-p contents)
+                 (if (if (featurep 'xemacs)
+                         (string-match "[^\000-\377]" contents)
+                       (multibyte-string-p contents))
                      (progn
-                       (mm-enable-multibyte)
+                       (set-buffer-multibyte t)
                        (insert contents)
                        (unless raw
                          (setq charset (mm-encode-body charset))))
                    (insert contents)))))
              (if (setq encoding (cdr (assq 'encoding cont)))
                  (setq encoding (intern (downcase encoding))))
-             (setq encoding (mm-encode-buffer type encoding)
-                   coded (string-as-multibyte (buffer-string))))
+             (setq encoding (mm-encode-buffer type encoding))
+             (setq coded (decode-coding-string (buffer-string) 'us-ascii)))
            (mml-insert-mime-headers cont type charset encoding nil)
            (insert "\n" coded))))
        ((eq (car cont) 'external)