Mail from first header

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

@@ -2204,18 +2204,17 @@ public class MessageHelper {
     }
 
     Address[] getMailFrom(String[] headers) {
-        if (headers == null)
+        if (headers == null || headers.length == 0)
             return null;
 
         Address[] mailfrom = null;
-        for (String header : headers) {
+        String spf = getKeyValues(headers[0]).get("spf");
-            String spf = getKeyValues(header).get("spf");
         if (spf == null)
-                continue;
+            return null;
 
         int i = spf.indexOf(SMTP_MAILFORM + "=");
         if (i < 0)
-                continue;
+            return null;
 
         String v = spf.substring(i + SMTP_MAILFORM.length() + 1);
         int s = v.indexOf(' ');
@@ -2230,7 +2229,6 @@ public class MessageHelper {
         } catch (Throwable ex) {
             Log.w(ex);
         }
-        }
 
         return mailfrom;
     }