From fda54ec183bfa61ffc8c7383d73c201177025d90 Mon Sep 17 00:00:00 2001
From: ueno <ueno>
Date: Wed, 20 Dec 2006 06:28:39 +0000
Subject: [PATCH] (epa-last-coding-system-specified): New variable.
 (epa-decrypt-region): Try to decode with the
 epa-coding-system-used text property.
 (epa--select-safe-coding-system): New function.
 (epa-verify-region): Try to decode with the
 epa-coding-system-used text property. (epa-sign-region):
 Query user to select coding-system to encode; set the
 epa-coding-system-used text property on the result.
 (epa-encrypt-region): Ditto.

---
 ChangeLog |    9 ++++++
 epa.el    |  100 +++++++++++++++++++++++++++++++++++++++++++------------------
 2 files changed, 80 insertions(+), 29 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 75fc4f1..aa4e5b3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,15 @@
 	(epa-sign-file): Save the output to *.p7s or *.p7m file if
 	epa-protocol is CMS.
 	(epa-encrypt-file): Ditto.
+	(epa-last-coding-system-specified): New variable.
+	(epa-decrypt-region): Try to decode with the
+	epa-coding-system-used text property.
+	(epa--select-safe-coding-system): New function.
+	(epa-verify-region): Try to decode with the epa-coding-system-used
+	text property.
+	(epa-sign-region): Query user to select coding-system to encode;
+	set the epa-coding-system-used text property on the result.
+	(epa-encrypt-region): Ditto.
 
 2006-12-19  Daiki Ueno  <ueno@unixuser.org>
 
diff --git a/epa.el b/epa.el
index a88f59b..f67ad6a 100644
--- a/epa.el
+++ b/epa.el
@@ -172,6 +172,7 @@ the separate window."
 (defvar epa-key nil)
 (defvar epa-list-keys-arguments nil)
 (defvar epa-info-buffer nil)
+(defvar epa-last-coding-system-specified nil)
 
 (defvar epa-keys-mode-map
   (let ((keymap (make-sparse-keymap)))
@@ -716,7 +717,10 @@ Don't use this command in Lisp programs!"
       (message "Decrypting...done")
       (delete-region start end)
       (goto-char start)
-      (insert (epa--decode-coding-string plain coding-system-for-read))
+      (insert (epa--decode-coding-string plain
+					 (or coding-system-for-read
+					     (get-text-property
+					      start 'epa-coding-system-used))))
       (if (epg-context-result-for context 'verify)
 	  (epa-display-info (epg-verify-result-to-string
 			     (epg-context-result-for context 'verify)))))))
@@ -749,6 +753,11 @@ Don't use this command in Lisp programs!"
 	  (let ((coding-system-for-read coding-system))
 	    (epa-decrypt-region start end)))))))
 
+(if (fboundp 'select-safe-coding-system)
+    (defalias 'epa--select-safe-coding-system 'select-safe-coding-system)
+  (defun epa--select-safe-coding-system (from to)
+    buffer-file-coding-system))
+
 ;;;###autoload
 (defun epa-verify-region (start end)
   "Verify the current region between START and END.
@@ -761,7 +770,9 @@ Don't use this command in Lisp programs!"
     (epg-verify-string context
 		       (epa--encode-coding-string
 			(buffer-substring start end)
-			coding-system-for-write))
+			(or coding-system-for-write
+			    (get-text-property start
+					       'epa-coding-system-used))))
     (if (epg-context-result-for context 'verify)
 	(epa-display-info (epg-verify-result-to-string
 			   (epg-context-result-for context 'verify))))))
@@ -797,31 +808,36 @@ Don't use this command in Lisp programs!"
 
 Don't use this command in Lisp programs!"
   (interactive
-   (list (region-beginning) (region-end)
-	 (epa-select-keys (epg-make-context epa-protocol)
-			  "Select keys for signing.
+   (progn
+     (setq epa-last-coding-system-specified
+	   (or coding-system-for-write
+	       (epa--select-safe-coding-system (region-beginning)
+					       (region-end))))
+     (list (region-beginning) (region-end)
+	   (epa-select-keys (epg-make-context epa-protocol)
+			    "Select keys for signing.
 If no one is selected, default secret key is used.  "
-			  nil t)
-	 (catch 'done
-	   (while t
-	     (message "Signature type (n,c,d,?) ")
-	     (let ((c (read-char)))
-	       (cond ((eq c ?c)
-		      (throw 'done 'clear))
-		     ((eq c ?d)
-		      (throw 'done 'detached))
-		     ((eq c ??)
-		      (with-output-to-temp-buffer "*Help*"
-			(save-excursion
-			  (set-buffer standard-output)
-			  (insert "\
+			    nil t)
+	   (catch 'done
+	     (while t
+	       (message "Signature type (n,c,d,?) ")
+	       (let ((c (read-char)))
+		 (cond ((eq c ?c)
+			(throw 'done 'clear))
+		       ((eq c ?d)
+			(throw 'done 'detached))
+		       ((eq c ??)
+			(with-output-to-temp-buffer "*Help*"
+			  (save-excursion
+			    (set-buffer standard-output)
+			    (insert "\
 n - Create a normal signature
 c - Create a cleartext signature
 d - Create a detached signature
 ? - Show this help
 "))))
-		     (t
-		      (throw 'done nil))))))))
+		       (t
+			(throw 'done nil)))))))))
   (save-excursion
     (let ((context (epg-make-context epa-protocol))
 	  signature)
@@ -838,11 +854,23 @@ d - Create a detached signature
       (setq signature (epg-sign-string context
 				       (epa--encode-coding-string
 					(buffer-substring start end)
-					coding-system-for-write)
+					epa-last-coding-system-specified)
 				       mode))
       (message "Signing...done")
       (delete-region start end)
-      (insert (epa--decode-coding-string signature coding-system-for-read)))))
+      (add-text-properties (point)
+			   (progn
+			     (insert (epa--decode-coding-string
+				      signature
+				      (or coding-system-for-read
+					  epa-last-coding-system-specified)))
+			     (point))
+			   (list 'epa-coding-system-used
+				 epa-last-coding-system-specified
+				 'front-sticky nil
+				 'rear-nonsticky t
+				 'start-open t
+				 'end-open t)))))
 
 ;;;###autoload
 (defun epa-encrypt-region (start end recipients)
@@ -850,10 +878,15 @@ d - Create a detached signature
 
 Don't use this command in Lisp programs!"
   (interactive
-   (list (region-beginning) (region-end)
-	 (epa-select-keys (epg-make-context epa-protocol)
-			  "Select recipients for encryption.
-If no one is selected, symmetric encryption will be performed.  ")))
+   (progn
+     (setq epa-last-coding-system-specified
+	   (or coding-system-for-write
+	       (epa--select-safe-coding-system (region-beginning)
+					       (region-end))))
+     (list (region-beginning) (region-end)
+	   (epa-select-keys (epg-make-context epa-protocol)
+			    "Select recipients for encryption.
+If no one is selected, symmetric encryption will be performed.  "))))
   (save-excursion
     (let ((context (epg-make-context epa-protocol))
 	  cipher)
@@ -869,11 +902,20 @@ If no one is selected, symmetric encryption will be performed.  ")))
       (setq cipher (epg-encrypt-string context
 				       (epa--encode-coding-string
 					(buffer-substring start end)
-					coding-system-for-write)
+					epa-last-coding-system-specified)
 				       recipients))
       (message "Encrypting...done")
       (delete-region start end)
-      (insert cipher))))
+      (add-text-properties (point)
+			   (progn
+			     (insert cipher)
+			     (point))
+			   (list 'epa-coding-system-used
+				 epa-last-coding-system-specified
+				 'front-sticky nil
+				 'rear-nonsticky t
+				 'start-open t
+				 'end-open t)))))
 
 ;;;###autoload
 (defun epa-delete-keys (keys &optional allow-secret)
-- 
1.7.10.4