@Override
    public ResultPage<DocumentUserPermissions> fetchDocumentUserPermissions(
            final FetchDocumentUserPermissionsRequest request) {
        Objects.requireNonNull(request, "Null request");
        final DocRef docRef = request.getDocRef();
        Objects.requireNonNull(docRef, "Null doc ref");
        if (ExplorerConstants.isFolderOrSystem(docRef)) {
            return fetchDeepFolderUserPermissions(request);
        } else {
            return fetchDeepDocumentUserPermissions(request);
        }
    }
Get permissions for users on documents or folders plus any permissions that they inherit from their group
membership.

@param request The Fetch request.
@return A result page of user permissions.
stroom-security/stroom-security-impl-db/src/main/java/stroom/security/impl/db/DocumentPermissionDaoImpl.java