Validate addresses before sending

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

@@ -188,6 +188,8 @@ public class FragmentCompose extends FragmentBase {
     static final int REDUCED_IMAGE_SIZE = 1440; // pixels
     static final int REDUCED_IMAGE_QUALITY = 90; // percent
 
+    private static final int ADDRESS_ELLIPSIZE = 50;
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -2169,13 +2171,37 @@ public class FragmentCompose extends FragmentBase {
                 InternetAddress abcc[] = null;
 
                 if (!TextUtils.isEmpty(to))
+                    try {
                         ato = InternetAddress.parse(to);
+                        if (action == R.id.action_send)
+                            for (InternetAddress address : ato)
+                                address.validate();
+                    } catch (AddressException ex) {
+                        throw new AddressException(context.getString(R.string.title_address_parse_error,
+                                Helper.ellipsize(to, ADDRESS_ELLIPSIZE), ex.getMessage()));
+                    }
 
                 if (!TextUtils.isEmpty(cc))
+                    try {
                         acc = InternetAddress.parse(cc);
+                        if (action == R.id.action_send)
+                            for (InternetAddress address : acc)
+                                address.validate();
+                    } catch (AddressException ex) {
+                        throw new AddressException(context.getString(R.string.title_address_parse_error,
+                                Helper.ellipsize(cc, ADDRESS_ELLIPSIZE), ex.getMessage()));
+                    }
 
                 if (!TextUtils.isEmpty(bcc))
+                    try {
                         abcc = InternetAddress.parse(bcc);
+                        if (action == R.id.action_send)
+                            for (InternetAddress address : abcc)
+                                address.validate();
+                    } catch (AddressException ex) {
+                        throw new AddressException(context.getString(R.string.title_address_parse_error,
+                                Helper.ellipsize(bcc, ADDRESS_ELLIPSIZE), ex.getMessage()));
+                    }
 
                 if (TextUtils.isEmpty(extra))
                     extra = null;

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

@@ -1217,4 +1217,11 @@ public class Helper {
         else
             return DateUtils.getRelativeTimeSpanString(context, millis);
     }
+
+    static String ellipsize(String text, int maxLen) {
+        if (text == null || text.length() < maxLen) {
+            return text;
+        }
+        return text.substring(0, maxLen) + "...";
+    }
 }

app/src/main/res/values/strings.xml

@@ -276,6 +276,7 @@
     <string name="title_no_name">Name missing</string>
     <string name="title_no_email">Email address missing</string>
     <string name="title_email_invalid">Email address invalid</string>
+    <string name="title_address_parse_error">Address \'%1$s\' invalid: %2$s</string>
     <string name="title_no_account">Account missing</string>
     <string name="title_no_host">Host name missing</string>
     <string name="title_no_user">User name missing</string>