send-email: add an auto option for transfer encoding

diff --git a/git-send-email.perl b/git-send-email.perl
index 8ec70e58ed5c4caace7701549038b63f9a3e9aad..1736a09d21ec4718526f579b49d9d1209a9c19aa 100755 (executable)
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -1739,9 +1739,8 @@ sub process_file {
        }
        if (defined $target_xfer_encoding) {
                $xfer_encoding = '8bit' if not defined $xfer_encoding;
-               $message = apply_transfer_encoding(
+               ($message, $xfer_encoding) = apply_transfer_encoding(
                        $message, $xfer_encoding, $target_xfer_encoding);
-               $xfer_encoding = $target_xfer_encoding;
        }
        if (defined $xfer_encoding) {
                push @xh, "Content-Transfer-Encoding: $xfer_encoding";
@@ -1852,13 +1851,16 @@ sub apply_transfer_encoding {
        $message = MIME::Base64::decode($message)
                if ($from eq 'base64');
 
+       $to = ($message =~ /.{999,}/) ? 'quoted-printable' : '8bit'
+               if $to eq 'auto';
+
        die __("cannot send message as 7bit")
                if ($to eq '7bit' and $message =~ /[^[:ascii:]]/);
-       return $message
+       return ($message, $to)
                if ($to eq '7bit' or $to eq '8bit');
-       return MIME::QuotedPrint::encode($message, "\n", 0)
+       return (MIME::QuotedPrint::encode($message, "\n", 0), $to)
                if ($to eq 'quoted-printable');
-       return MIME::Base64::encode($message, "\n")
+       return (MIME::Base64::encode($message, "\n"), $to)
                if ($to eq 'base64');
        die __("invalid transfer encoding");
 }