Workaround double encoded subjects

app/src/main/java/eu/faircode/email/MessageHelper.java

@@ -54,6 +54,7 @@ import javax.mail.internet.InternetAddress;
 import javax.mail.internet.MimeBodyPart;
 import javax.mail.internet.MimeMessage;
 import javax.mail.internet.MimeMultipart;
+import javax.mail.internet.MimeUtility;
 import javax.mail.internet.ParseException;
 
 public class MessageHelper {
@@ -435,6 +436,19 @@ public class MessageHelper {
             return null;
     }
 
+    String getSubject() throws MessagingException, UnsupportedEncodingException {
+        String subject = imessage.getSubject();
+        if (subject != null && subject.indexOf("=?") >= 0) {
+            String prev;
+            do {
+                prev = subject;
+                subject = MimeUtility.decodeText(subject);
+            }
+            while (!subject.equals(prev));
+        }
+        return subject;
+    }
+
     Integer getSize() throws MessagingException {
         int size = imessage.getSize();
         return (size < 0 ? null : size);

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -2379,7 +2379,7 @@ public class ServiceSynchronize extends LifecycleService {
             message.cc = helper.getCc();
             message.bcc = helper.getBcc();
             message.reply = helper.getReply();
-            message.subject = imessage.getSubject();
+            message.subject = helper.getSubject();
             message.size = helper.getSize();
             message.content = false;
             message.received = imessage.getReceivedDate().getTime();