Use channel I/O directly for file->string and string->file.

Here a string is an octet sequence, always in US-ASCII or UTF-8, so
we don't need the rigmarole of text I/O.

diff --git a/src/imail/imail-imap.scm b/src/imail/imail-imap.scm
index 9010ab4874ccf51cba52e0dffe68f4ce7a7478ec..975c55f8723233834d6d19c67030f7fad64195ed 100644 (file)
--- a/src/imail/imail-imap.scm
+++ b/src/imail/imail-imap.scm
@@ -2128,12 +2128,21 @@ USA.
       (newline port))))
 
 (define (string->file string pathname #!optional temporary-directory)
-  (call-with-temporary-output-file pathname temporary-directory
-    (lambda (port)
-      (port/set-coding port 'ISO-8859-1)
-      (write-string string port))))
+  (call-with-temporary-file-pathname temporary-directory
+    (lambda (temporary-pathname)
+      (let ((channel
+            (file-open-output-channel (->namestring temporary-pathname))))
+       (channel-write-block channel string 0 (string-length string))
+       (channel-close channel)
+       (rename-file temporary-pathname pathname)))))
 
 (define (call-with-temporary-output-file pathname temporary-directory receiver)
+  (call-with-temporary-file-pathname temporary-directory
+    (lambda (temporary-pathname)
+      (begin0 (call-with-output-file temporary-pathname receiver)
+       (rename-file temporary-pathname pathname)))))
+
+(define (call-with-temporary-file-pathname temporary-directory receiver)
   (if (or (not temporary-directory)
          (default-object? temporary-directory))
       (call-with-output-file temporary-directory receiver)
@@ -2144,17 +2153,18 @@ USA.
           (if done?
               (error "Re-entry prohibited into temporary file creation.")))
         (lambda ()
-          (let ((result (call-with-output-file temporary-pathname receiver)))
-            (rename-file temporary-pathname pathname)
-            result))
+          (receiver temporary-pathname))
         (lambda ()
           (set! done? #t)
           (deallocate-temporary-file temporary-pathname))))))
 
 (define (file->string pathname)
-  (call-with-output-string
-    (lambda (port)
-      (file->port pathname port))))
+  (let* ((channel (file-open-input-channel (->namestring pathname)))
+        (length (channel-file-length channel))
+        (buffer (string-allocate length)))
+    (channel-read-block channel buffer 0 length)
+    (channel-close channel)
+    buffer))
 
 (define (file->port pathname output-port)
   (call-with-input-file pathname