ReqHandler.hh

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/*
 * Copyright (C) 2014 Open Source Robotics Foundation
 *
 * 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.
 *
*/

#ifndef IGN_TRANSPORT_REQHANDLER_HH_
#define IGN_TRANSPORT_REQHANDLER_HH_

#ifdef _MSC_VER
#pragma warning(push, 0)
#endif
#include <google/protobuf/message.h>
#ifdef _MSC_VER
#pragma warning(pop)
#endif

#include <condition_variable>
#include <functional>
#include <memory>
#include <string>

#include "ignition/transport/Helpers.hh"
#include "ignition/transport/TransportTypes.hh"
#include "ignition/transport/Uuid.hh"

namespace ignition
{
  namespace transport
  {
    class IGNITION_TRANSPORT_VISIBLE IReqHandler
    {
      public: explicit IReqHandler(const std::string &_nUuid)
        : rep(""),
          result(false),
          hUuid(Uuid().ToString()),
          nUuid(_nUuid),
          requested(false),
          repAvailable(false)
      {
      }

      public: virtual ~IReqHandler() = default;

      public: virtual void NotifyResult(const std::string &_rep,
                                        const bool _result) = 0;

      public: std::string NodeUuid() const
      {
        return this->nUuid;
      }

      public: std::string Response() const
      {
        return this->rep;
      }

      public: bool Result() const
      {
        return this->result;
      }

      public: bool Requested() const
      {
        return this->requested;
      }

      public: void Requested(const bool _value)
      {
        this->requested = _value;
      }

      public: virtual bool Serialize(std::string &_buffer) const = 0;

      public: std::string HandlerUuid() const
      {
        return this->hUuid;
      }

      public: template<typename Lock> bool WaitUntil(Lock &_lock,
                                                    const unsigned int _timeout)
      {
        auto now = std::chrono::system_clock::now();
        return this->condition.wait_until(_lock,
          now + std::chrono::milliseconds(_timeout),
          [this]
          {
            return this->repAvailable;
          });
      }

      public: virtual std::string ReqTypeName() const = 0;

      public: virtual std::string RepTypeName() const = 0;

      protected: std::condition_variable_any condition;

      protected: std::string rep;

      protected: bool result;

      protected: std::string hUuid;

      private: std::string nUuid;

      private: bool requested;

      public: bool repAvailable;
    };

    template <typename Req, typename Rep> class ReqHandler
      : public IReqHandler
    {
      // Documentation inherited.
      public: explicit ReqHandler(const std::string &_nUuid)
        : IReqHandler(_nUuid)
      {
      }

      public: std::shared_ptr<Rep> CreateMsg(const std::string &_data) const
      {
        // Instantiate a specific protobuf message
        std::shared_ptr<Rep> msgPtr(new Rep());

        // Create the message using some serialized data
        if (!msgPtr->ParseFromString(_data))
        {
          std::cerr << "ReqHandler::CreateMsg() error: ParseFromString failed"
                    << std::endl;
        }

        return msgPtr;
      }

      public: void SetCallback(const std::function <void(
        const Rep &_rep, const bool _result)> &_cb)
      {
        this->cb = _cb;
      }

      public: void SetMessage(const Req *_reqMsg)
      {
        if (!_reqMsg)
        {
          std::cerr << "ReqHandler::SetMessage() _reqMsg is null" << std::endl;
          return;
        }

        this->reqMsg.CopyFrom(*_reqMsg);
      }

      public: void SetResponse(const Rep * /*_repMsg*/)
      {
      }

      // Documentation inherited
      public: bool Serialize(std::string &_buffer) const
      {
        if (!this->reqMsg.SerializeToString(&_buffer))
        {
          std::cerr << "ReqHandler::Serialize(): Error serializing the request"
                    << std::endl;
          return false;
        }

        return true;
      }

      // Documentation inherited.
      public: void NotifyResult(const std::string &_rep, const bool _result)
      {
        // Execute the callback (if existing).
        if (this->cb)
        {
          // Instantiate the specific protobuf message associated to this topic.
          auto msg = this->CreateMsg(_rep);

          this->cb(*msg, _result);
        }
        else
        {
          this->rep = _rep;
          this->result = _result;
        }

        this->repAvailable = true;
        this->condition.notify_one();
      }

      // Documentation inherited.
      public: virtual std::string ReqTypeName() const
      {
        return Req().GetTypeName();
      }

      // Documentation inherited.
      public: virtual std::string RepTypeName() const
      {
        return Rep().GetTypeName();
      }

      private: Req reqMsg;

      private: std::function<void(const Rep &_rep, const bool _result)> cb;
    };

    template <> class ReqHandler<google::protobuf::Message,
                                 google::protobuf::Message>
      : public IReqHandler
    {
      // Documentation inherited.
      public: explicit ReqHandler(const std::string &_nUuid)
        : IReqHandler(_nUuid)
      {
      }

      public: void SetMessage(const google::protobuf::Message *_reqMsg)
      {
        if (!_reqMsg)
        {
          std::cerr << "ReqHandler::SetMessage() _reqMsg is null" << std::endl;
          return;
        }

        this->reqMsg = _reqMsg->New();
        this->reqMsg->CopyFrom(*_reqMsg);
      }

      public: void SetResponse(const google::protobuf::Message *_repMsg)
      {
        if (!_repMsg)
        {
          std::cerr << "ReqHandler::SetResponse() _repMsg is null" << std::endl;
          return;
        }

        this->repMsg = _repMsg->New();
        this->repMsg->CopyFrom(*_repMsg);
      }

      // Documentation inherited
      public: bool Serialize(std::string &_buffer) const
      {
        if (!this->reqMsg)
        {
          std::cerr << "ReqHandler::Serialize() reqMsg is null" << std::endl;
          return false;
        }

        if (!this->reqMsg->SerializeToString(&_buffer))
        {
          std::cerr << "ReqHandler::Serialize(): Error serializing the request"
                    << std::endl;
          return false;
        }

        return true;
      }

      // Documentation inherited.
      public: void NotifyResult(const std::string &_rep, const bool _result)
      {
        this->rep = _rep;
        this->result = _result;

        this->repAvailable = true;
        this->condition.notify_one();
      }

      // Documentation inherited.
      public: virtual std::string ReqTypeName() const
      {
        if (this->reqMsg)
          return this->reqMsg->GetTypeName();
        else
        {
          std::cerr << "ReqHandler::ReqTypeName() Warning: Using ReqTypeName() "
                    << "without type information" << std::endl;
          return "";
        }
      }

      public: virtual std::string RepTypeName() const
      {
        if (this->repMsg)
          return this->repMsg->GetTypeName();
        else
        {
          std::cerr << "ReqHandler::RepTypeName() Warning: Using RepTypeName() "
                    << "without type information" << std::endl;
          return "";
        }
      }

      private: google::protobuf::Message *reqMsg = nullptr;

      private: google::protobuf::Message *repMsg = nullptr;
    };
  }
}

#endif