YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

//--------------------------------------------------------------------------------------------------

// Copyright (c) YugaByte, Inc.

//

// Licensed 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.

//

//

// This class defines a CQL statement. A CQL statement extends from a SQL statement to handle query

// ID and caching prepared statements in a list.

//--------------------------------------------------------------------------------------------------

#ifndef YB_YQL_CQL_CQLSERVER_CQL_STATEMENT_H_

#define YB_YQL_CQL_CQLSERVER_CQL_STATEMENT_H_

#include <list>

#include "yb/yql/cql/ql/statement.h"

#include "yb/yql/cql/ql/util/cql_message.h"

namespace yb {

namespace cqlserver {

class CQLStatement;

// A map of CQL query id to the prepared statement for caching the prepared statments. Shared_ptr

// is used so that a prepared statement can be aged out and removed from the cache without deleting

// it when it is being executed by another client in another thread.

using CQLStatementMap = std::unordered_map<ql::CQLMessage::QueryId, std::shared_ptr<CQLStatement>>;

// A LRU list of CQL statements and position in the list.

using CQLStatementList = std::list<std::shared_ptr<CQLStatement>>;

using CQLStatementListPos = CQLStatementList::iterator;

// A CQL statement that is prepared and cached.

class CQLStatement : public ql::Statement {

 public:

  CQLStatement(const std::string& keyspace, const std::string& query, CQLStatementListPos pos);

  ~CQLStatement();

  // Return the query id.

  ql::CQLMessage::QueryId query_id() const { return GetQueryId(keyspace_, text_); }

  // Get/set position of the statement in the LRU.

  CQLStatementListPos pos() const { return pos_; }

  void set_pos(CQLStatementListPos pos) const { pos_ = pos; }

  // Return the query id of a statement.

  static ql::CQLMessage::QueryId GetQueryId(const std::string& keyspace, const std::string& query);

 private:

  // Position of the statement in the LRU.

  mutable CQLStatementListPos pos_;

};

}  // namespace cqlserver

}  // namespace yb

#endif  // YB_YQL_CQL_CQLSERVER_CQL_STATEMENT_H_