Refactoring

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

@@ -62,15 +62,10 @@ public class DnsHelper {
 
         for (Address address : addresses) {
             String email = ((InternetAddress) address).getAddress();
-            if (email == null)
+            String domain = UriHelper.getEmailDomain(email);
+            if (domain == null)
                 continue;
 
-            int d = email.lastIndexOf("@");
-            if (d < 0)
-                continue;
-
-            String domain = email.substring(d + 1);
-
             boolean found = true;
             try {
                 SimpleResolver resolver = new SimpleResolver(getDnsServer(context));

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

@@ -219,7 +219,7 @@ public class EmailProvider implements Parcelable {
 
     @NonNull
     static EmailProvider fromEmail(Context context, String email, Discover discover) throws IOException {
-        int at = email.indexOf("@");
+        int at = email.indexOf('@');
         String domain = (at < 0 ? email : email.substring(at + 1));
         if (at < 0)
             email = "someone@" + domain;

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

@@ -4112,7 +4112,7 @@ public class FragmentCompose extends FragmentBase {
                                     }
                                     if (preferred != null) {
                                         String from = ((InternetAddress) preferred).getAddress();
-                                        data.draft.extra = from.substring(0, from.indexOf("@"));
+                                        data.draft.extra = UriHelper.getEmailUser(from);
                                     }
                                 }
                             }
@@ -5229,14 +5229,8 @@ public class FragmentCompose extends FragmentBase {
                                 String[] internals = identity.internal.split(",");
                                 for (Address recipient : recipients) {
                                     String email = ((InternetAddress) recipient).getAddress();
-                                    if (TextUtils.isEmpty(email))
-                                        continue;
-
-                                    int at = email.lastIndexOf('@');
-                                    if (at < 0)
-                                        continue;
-                                    String domain = email.substring(at + 1).trim();
-                                    if (TextUtils.isEmpty(domain))
+                                    String domain = UriHelper.getEmailDomain(email);
+                                    if (domain == null)
                                         continue;
 
                                     boolean found = false;

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

@@ -31,6 +31,17 @@ public class UriHelper {
         return host;
     }
 
+    static String getEmailUser(String address) {
+        if (address == null)
+            return null;
+
+        int at = address.indexOf('@');
+        if (at > 0)
+            return address.substring(0, at);
+
+        return null;
+    }
+
     static String getEmailDomain(String address) {
         if (address == null)
             return null;
@@ -39,6 +50,6 @@ public class UriHelper {
         if (at > 0)
             return address.substring(at + 1);
 
-        return address;
+        return null;
     }
 }