text: /** @file
  
    Implementation of nexthop consistent hash selections strategies.
  
    @section license License
  
    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.
   */
  
  #pragma once
  
  #include <map>
  #include <vector>
  #include "tscore/HashSip.h"
  #include "NextHopSelectionStrategy.h"
  
  enum NHHashKeyType {
    NH_URL_HASH_KEY = 0,
    NH_HOSTNAME_HASH_KEY,
    NH_PATH_HASH_KEY, // default, consistent hash uses the request url path
    NH_PATH_QUERY_HASH_KEY,
    NH_PATH_FRAGMENT_HASH_KEY,
    NH_CACHE_HASH_KEY
  };
  
  class NextHopConsistentHash : public NextHopSelectionStrategy
  {
    std::vector<std::shared_ptr<ATSConsistentHash>> rings;
  
    uint64_t getHashKey(uint64_t sm_id, const HttpRequestData &hrdata, ATSHash64 *h);
  
  public:
    NHHashKeyType hash_key = NH_PATH_HASH_KEY;
  
    NextHopConsistentHash() = delete;
    NextHopConsistentHash(const std::string_view name, const NHPolicyType &policy) : NextHopSelectionStrategy(name, policy) {}
    ~NextHopConsistentHash();
    bool Init(ts::Yaml::Map &n);
    void findNextHop(TSHttpTxn txnp, void *ih = nullptr, time_t now = 0) override;
    std::shared_ptr<HostRecord> chashLookup(const std::shared_ptr<ATSConsistentHash> &ring, uint32_t cur_ring, ParentResult &result,
                                            HttpRequestData &request_info, bool *wrapped, uint64_t sm_id);
  };
  