(rmail-enable-multibyte): New variable

(rmail): Bind coding-system-for-read to raw-text.  Set the buffer
multibyte if necessary.
(rmail-convert-file): Call rmail-decode-babyl-format only when we
don't have to call rmail-convert-to-babyl-format.
(rmail-decode-babyl-format): If rmail-file-coding-system is nil,
detect it.
(rmail-get-new-mail): Bind rmail-enable-multibyte locally.
(rmail-convert-to-babyl-format): Check the value of
rmail-enable-multibyte instead of enable-multibyte-characters.

1 files changed, 48 insertions, 22 deletions

diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index 0371837b6a2..2eb712e9338 100644
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -429,6 +429,8 @@ is non-nil.")
 
 ;;;; *** Rmail Mode ***
 
+(defvar rmail-enable-multibyte nil)
+
 ;;;###autoload
 (defun rmail (&optional file-name-arg)
   "Read and edit incoming mail.
@@ -452,6 +454,14 @@ If `rmail-display-summary' is non-nil, make a summary for this RMAIL file."
                (setq rmail-enable-mime nil))))
   (let* ((file-name (expand-file-name (or file-name-arg rmail-file-name)))
          (existed (get-file-buffer file-name))
+         (rmail-enable-multibyte (default-value 'enable-multibyte-characters))
+         ;; Since the file may contain messages of different encodings
+         ;; at the tail (non-BYBYL part), we can't decode them at once
+         ;; on reading.  So, at first, we read the file without text
+         ;; code conversion, then decode the messages one by one by
+         ;; rmail-decode-babyl-format or
+         ;; rmail-convert-to-babyl-format.
+         (coding-system-for-read (and rmail-enable-multibyte 'raw-text))
          run-mail-hook msg-shown)
     ;; Like find-file, but in the case where a buffer existed
     ;; and the file was reverted, recompute the message-data.
@@ -478,6 +488,11 @@ If `rmail-display-summary' is non-nil, make a summary for this RMAIL file."
       (rmail-mode-2)
       ;; Convert all or part to Babyl file if possible.
       (rmail-convert-file)
+      ;; As we have read a file by raw-text, the buffer is set to
+      ;; unibyte.  We must make it multibyte if necessary.
+      (if (and rmail-enable-multibyte
+               (not enable-multibyte-characters))
+          (set-buffer-multibyte t))
       (goto-char (point-max))
       (if (null rmail-inbox-list)
           (progn
@@ -531,13 +546,6 @@ If `rmail-display-summary' is non-nil, make a summary for this RMAIL file."
            ;; Non-empty file in non-RMAIL format.  Add header and convert.
            (setq convert t)
            (rmail-insert-rmail-file-header)))
-    (if (and (not convert)
-             (not rmail-enable-mime)
-             rmail-file-coding-system)
-        ;; Decode coding system of BABYL part at the head only.  The
-        ;; remaining non BABYL parts are decoded in
-        ;; rmail-convert-to-babyl-format if necessary.
-        (rmail-decode-babyl-format))
     ;; If file was not a Babyl file or if there are
     ;; Unix format messages added at the end,
     ;; convert file as necessary.
@@ -556,7 +564,11 @@ If `rmail-display-summary' is non-nil, make a summary for this RMAIL file."
           (search-forward "\n\^_" nil t)
           (narrow-to-region (point) (point-max))
           (rmail-convert-to-babyl-format)
-          (message "Converting to Babyl format...done")))))
+          (message "Converting to Babyl format...done"))
+      (if (and (not rmail-enable-mime)
+               rmail-enable-multibyte)
+          ;; We still have to decode BABYL part.
+          (rmail-decode-babyl-format)))))
 
 ;;; I have checked that adding "-*- rmail -*-" to the BABYL OPTIONS line
 ;;; will not cause emacs 18.55 problems.
@@ -571,22 +583,34 @@ Note:   If you are seeing it in rmail,
 Note:    it means the file has no messages in it.\n\^_")))
 
 ;; Decode Babyl formated part at the head of current buffer by
-;; rmail-file-coding-system.
+;; rmail-file-coding-system, or if it is nil, do auto conversion.
 
 (defun rmail-decode-babyl-format ()
   (let ((modifiedp (buffer-modified-p))
         (buffer-read-only nil)
-        pos)
+        from to)
     (goto-char (point-min))
     (search-forward "\n\^_" nil t)      ; Skip BYBYL header.
-    (setq pos (point))
-    (message "Decoding messages...")
-    (while (search-forward "\n\^_" nil t)
-      (decode-coding-region pos (point) rmail-file-coding-system)
-      (setq pos (point)))
-    (message "Decoding messages...done")
-    (set-buffer-file-coding-system rmail-file-coding-system)
-    (set-buffer-modified-p modifiedp)))
+    (setq from (point))
+    (goto-char (point-max))
+    (search-backward "\n\^_" from 'mv)
+    (setq to (point))
+    (if (not (and rmail-file-coding-system
+                  (coding-system-p rmail-file-coding-system)))
+        (setq rmail-file-coding-system (detect-coding-region from to t)))
+    (if (not (eq rmail-file-coding-system 'undecided))
+        (let ((count 1))
+          (goto-char from)
+          (while (search-forward "\n\^_" nil t)
+            (decode-coding-region from (1- (point)) rmail-file-coding-system)
+            (goto-char (point))
+            (setq from (point))
+            (if (= (% count 10) 0)
+                (message "Decoding messages (%d)..." count))
+            (setq count (1+ count)))
+          (message "Decoding messages (%d)...done" count)
+          (set-buffer-file-coding-system rmail-file-coding-system)
+          (set-buffer-modified-p modifiedp)))))
 
 (if rmail-mode-map
     nil
@@ -1085,6 +1109,7 @@ It returns t if it got any new messages."
       (setq buffer-undo-list nil))
   (let ((all-files (if file-name (list file-name)
                      rmail-inbox-list))
+        (rmail-enable-multibyte (default-value 'enable-multibyte-characters))
         found)
     (unwind-protect
         (progn
@@ -1396,9 +1421,10 @@ Optional DEFAULT is password to start with."
                                 (skip-chars-forward " \t\n")
                                 (point)))
                (or rmail-enable-mime
-                   (not rmail-file-coding-system)
+                   (not rmail-enable-multibyte)
                    (decode-coding-region start (point)
-                                         rmail-file-coding-system))
+                                         (or rmail-file-coding-system
+                                             'undecided)))
                (narrow-to-region (point) (point-max)))
               ;;*** MMDF format
               ((let ((case-fold-search t))
@@ -1414,7 +1440,7 @@ Optional DEFAULT is password to start with."
                    (while (search-forward "\n\^_" nil t); single char "\^_"
                      (replace-match "\n^_")))); 2 chars: "^" and "_"
                (or rmail-enable-mime
-                   (not enable-multibyte-characters)
+                   (not rmail-enable-multibyte)
                    (decode-coding-region start (point) 'undecided))
                (narrow-to-region (point) (point-max))
                (setq count (1+ count)))
@@ -1490,7 +1516,7 @@ Optional DEFAULT is password to start with."
                      (replace-match "\n^_")))); 2 chars: "^" and "_"
                (insert ?\^_)
                (or rmail-enable-mime
-                   (not enable-multibyte-characters)
+                   (not rmail-enable-multibyte)
                    (decode-coding-region start (point) 'undecided))
                (narrow-to-region (point) (point-max)))
               ;;