Ensure that X selection convertors properly encode returned strings.

Though not itself a regression, this bug was exposed by the support
for MULTIPLE selections, which is new to Emacs 24 (see Bug#11315).

* lisp/select.el (xselect--encode-string): New function, split from
xselect-convert-to-string.
(xselect-convert-to-string): Use it.
(xselect-convert-to-filename, xselect-convert-to-os)
(xselect-convert-to-host, xselect-convert-to-user): Ensure that
returned strings are properly encoded.

2 files changed, 34 insertions, 22 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index eb293610a67..834f54bc96e 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,12 @@
+2012-04-24  Chong Yidong  <cyd@gnu.org>
+
+        * select.el (xselect--encode-string): New function, split from
+        xselect-convert-to-string.
+        (xselect-convert-to-string): Use it.
+        (xselect-convert-to-filename, xselect-convert-to-os)
+        (xselect-convert-to-host, xselect-convert-to-user): Ensure that
+        returned strings are properly encoded (Bug#11315).
+
 2012-04-22  Chong Yidong  <cyd@gnu.org>
 
         * simple.el (delete-active-region): Move to killing custom group.
diff --git a/lisp/select.el b/lisp/select.el
index 0260eba4682..3948fcc5456 100644
--- a/lisp/select.el
+++ b/lisp/select.el
@@ -213,30 +213,25 @@ two markers or an overlay.  Otherwise, it is nil."
 (defun xselect--int-to-cons (n)
   (cons (ash n -16) (logand n 65535)))
 
-(defun xselect-convert-to-string (_selection type value)
-  (let (str coding)
-    ;; Get the actual string from VALUE.
-    (cond ((stringp value)
-           (setq str value))
-          ((setq value (xselect--selection-bounds value))
-           (with-current-buffer (nth 2 value)
-             (setq str (buffer-substring (nth 0 value)
-                                         (nth 1 value))))))
-    (when str
-      ;; If TYPE is nil, this is a local request, thus return STR as
-      ;; is.  Otherwise, encode STR.
-      (if (not type)
-          str
-        (setq coding (or next-selection-coding-system selection-coding-system))
+(defun xselect--encode-string (type str &optional can-modify)
+  (when str
+    ;; If TYPE is nil, this is a local request; return STR as-is.
+    (if (null type)
+        str
+      ;; Otherwise, encode STR.
+      (let ((coding (or next-selection-coding-system
+                        selection-coding-system)))
         (if coding
             (setq coding (coding-system-base coding)))
         (let ((inhibit-read-only t))
           ;; Suppress producing escape sequences for compositions.
+          ;; But avoid modifying the string if it's a buffer name etc.
+          (unless can-modify (setq str (substring str 0)))
           (remove-text-properties 0 (length str) '(composition nil) str)
+          ;; TEXT is a polymorphic target.  Select the actual type
+          ;; from `UTF8_STRING', `COMPOUND_TEXT', `STRING', and
+          ;; `C_STRING'.
           (if (eq type 'TEXT)
-              ;; TEXT is a polymorphic target.  We must select the
-              ;; actual type from `UTF8_STRING', `COMPOUND_TEXT',
-              ;; `STRING', and `C_STRING'.
               (if (not (multibyte-string-p str))
                   (setq type 'C_STRING)
                 (let (non-latin-1 non-unicode eight-bit)
@@ -279,6 +274,14 @@ two markers or an overlay.  Otherwise, it is nil."
       (setq next-selection-coding-system nil)
       (cons type str))))
 
+(defun xselect-convert-to-string (_selection type value)
+  (let ((str (cond ((stringp value) value)
+                   ((setq value (xselect--selection-bounds value))
+                    (with-current-buffer (nth 2 value)
+                      (buffer-substring (nth 0 value)
+                                        (nth 1 value)))))))
+    (xselect--encode-string type str t)))
+
 (defun xselect-convert-to-length (_selection _type value)
   (let ((len (cond ((stringp value)
                     (length value))
@@ -311,7 +314,7 @@ two markers or an overlay.  Otherwise, it is nil."
 
 (defun xselect-convert-to-filename (_selection _type value)
   (when (setq value (xselect--selection-bounds value))
-    (buffer-file-name (nth 2 value))))
+    (xselect--encode-string 'TEXT (buffer-file-name (nth 2 value)))))
 
 (defun xselect-convert-to-charpos (_selection _type value)
   (when (setq value (xselect--selection-bounds value))
@@ -337,13 +340,13 @@ two markers or an overlay.  Otherwise, it is nil."
                             (xselect--int-to-cons (max beg end))))))))
 
 (defun xselect-convert-to-os (_selection _type _size)
-  (symbol-name system-type))
+  (xselect--encode-string 'TEXT (symbol-name system-type)))
 
 (defun xselect-convert-to-host (_selection _type _size)
-  (system-name))
+  (xselect--encode-string 'TEXT (system-name)))
 
 (defun xselect-convert-to-user (_selection _type _size)
-  (user-full-name))
+  (xselect--encode-string 'TEXT (user-full-name)))
 
 (defun xselect-convert-to-class (_selection _type _size)
   "Convert selection to class.