text: // Licensed to the Apache Software Foundation (ASF) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The ASF licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #include "resource_provider/validation.hpp"
  
  #include <stout/none.hpp>
  #include <stout/unreachable.hpp>
  
  using mesos::resource_provider::Call;
  
  namespace mesos {
  namespace internal {
  namespace resource_provider {
  namespace validation {
  namespace call {
  
  Option<Error> validate(const Call& call)
  {
    if (!call.IsInitialized()) {
      return Error("Not initialized: " + call.InitializationErrorString());
    }
  
    if (!call.has_type()) {
      return Error("Expecting 'type' to be present");
    }
  
    switch(call.type()) {
      case Call::UNKNOWN: {
        return None();
      }
  
      case Call::SUBSCRIBE: {
        if (!call.has_subscribe()) {
          return Error("Expecting 'subscribe' to be present");
        }
  
        return None();
      }
  
      case Call::UPDATE: {
        if (!call.has_resource_provider_id()) {
          return Error("Expecting 'resource_provider_id' to be present");
        }
  
        if (!call.has_update()) {
          return Error("Expecting 'update' to be present");
        }
  
        return None();
      }
    }
  
    UNREACHABLE();
  }
  
  } // namespace call {
  } // namespace validation {
  } // namespace resource_provider {
  } // namespace internal {
  } // namespace mesos {
  