Refactoring

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

@@ -123,6 +123,7 @@ public class MessageHelper {
     private boolean ensuredStructure = false;
     private MimeMessage imessage;
     private String hash = null;
+    private InternetHeaders reportHeaders = null;
 
     private static File cacheDir = null;
 
@@ -1170,33 +1171,10 @@ public class MessageHelper {
         if (refs != null)
             result.addAll(Arrays.asList(getReferences(refs)));
 
-        try {
+        // Merge references of reported message for threading
-            // Merge references of original message for threading
+        InternetHeaders iheaders = getReportHeaders();
-            if (imessage.isMimeType("multipart/report")) {
+        if (iheaders != null) {
-                ContentType ct = new ContentType(imessage.getContentType());
+            String arefs = iheaders.getHeader("References", null);
-                String reportType = ct.getParameter("report-type");
-                if ("delivery-status".equalsIgnoreCase(reportType) ||
-                        "disposition-notification".equalsIgnoreCase(reportType)) {
-                    String arefs = null;
-                    String amsgid = null;
-
-                    MessageParts parts = new MessageParts();
-                    getMessageParts(imessage, parts, null);
-                    for (AttachmentPart apart : parts.attachments)
-                        if ("text/rfc822-headers".equalsIgnoreCase(apart.attachment.type)) {
-                            InternetHeaders iheaders = new InternetHeaders(apart.part.getInputStream());
-                            arefs = iheaders.getHeader("References", null);
-                            amsgid = iheaders.getHeader("Message-Id", null);
-                            break;
-                        } else if ("message/rfc822".equalsIgnoreCase(apart.attachment.type)) {
-                            Properties props = MessageHelper.getSessionProperties();
-                            Session isession = Session.getInstance(props, null);
-                            MimeMessage amessage = new MimeMessage(isession, apart.part.getInputStream());
-                            arefs = amessage.getHeader("References", null);
-                            amsgid = amessage.getHeader("Message-Id", null);
-                            break;
-                        }
-
             if (arefs != null)
                 for (String ref : getReferences(arefs))
                     if (!result.contains(ref)) {
@@ -1204,6 +1182,7 @@ public class MessageHelper {
                         result.add(ref);
                     }
 
+            String amsgid = iheaders.getHeader("Message-Id", null);
             if (amsgid != null) {
                 String msgid = MimeUtility.unfold(amsgid);
                 if (!result.contains(msgid)) {
@@ -1212,10 +1191,6 @@ public class MessageHelper {
                 }
             }
         }
-            }
-        } catch (Throwable ex) {
-            Log.w(ex);
-        }
 
         return result.toArray(new String[0]);
     }
@@ -1247,8 +1222,23 @@ public class MessageHelper {
         if (header != null)
             header = MimeUtility.unfold(header);
 
-        if (header == null)
+        if (header == null) {
+            // Use reported message ID as synthetic in-reply-to
+            InternetHeaders iheaders = getReportHeaders();
+            if (iheaders != null) {
+                header = iheaders.getHeader("Message-Id", null);
+                if (header != null)
+                    Log.i("rfc822 id=" + header);
+            }
+        }
+
+        return header;
+    }
+
+    private InternetHeaders getReportHeaders() {
         try {
+            ensureStructure();
+
             if (imessage.isMimeType("multipart/report")) {
                 ContentType ct = new ContentType(imessage.getContentType());
                 String reportType = ct.getParameter("report-type");
@@ -1258,21 +1248,14 @@ public class MessageHelper {
                     getMessageParts(imessage, parts, null);
                     for (AttachmentPart apart : parts.attachments)
                         if ("text/rfc822-headers".equalsIgnoreCase(apart.attachment.type)) {
-                                InternetHeaders iheaders = new InternetHeaders(apart.part.getInputStream());
+                            reportHeaders = new InternetHeaders(apart.part.getInputStream());
-                                String amsgid = iheaders.getHeader("Message-Id", null);
+                            break;
-                                if (amsgid != null) {
-                                    Log.i("rfc822 id=" + amsgid);
-                                    return amsgid;
-                                }
                         } else if ("message/rfc822".equalsIgnoreCase(apart.attachment.type)) {
                             Properties props = MessageHelper.getSessionProperties();
                             Session isession = Session.getInstance(props, null);
                             MimeMessage amessage = new MimeMessage(isession, apart.part.getInputStream());
-                                String amsgid = amessage.getHeader("Message-Id", null);
+                            reportHeaders = amessage.getHeaders();
-                                if (amsgid != null) {
+                            break;
-                                    Log.i("rfc822 id=" + amsgid);
-                                    return amsgid;
-                                }
                         }
                 }
             }
@@ -1280,7 +1263,7 @@ public class MessageHelper {
             Log.w(ex);
         }
 
-        return header;
+        return reportHeaders;
     }
 
     String getThreadId(Context context, long account, long folder, long uid) throws MessagingException {

app/src/main/java/javax/mail/internet/MimeMessage.java

@@ -2008,6 +2008,10 @@ public class MimeMessage extends Message implements MimePart {
 	headers.removeHeader(name);
     }
 
+	public InternetHeaders getHeaders() {
+	return headers;
+	}
+
     /**
      * Return all the headers from this Message as an enumeration
      * of Header objects. <p>