Task.h

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
#ifndef O2_FRAMEWORK_TASK_H_
#define O2_FRAMEWORK_TASK_H_
 
#include "Framework/AlgorithmSpec.h"
#include "Framework/CallbackService.h"
#include "Framework/EndOfStreamContext.h"
#include <memory>
 
namespace o2::framework
{
 
class Task
{
 public:
  virtual ~Task();
  virtual void init(InitContext& context) {}
  virtual void run(ProcessingContext& context) = 0;
 
  virtual void endOfStream(EndOfStreamContext& context) {}
 
  virtual void finaliseCCDB(ConcreteDataMatcher& matcher, void* obj)
  {
    LOGP(debug, "CCDB deserialization invoked");
  }
 
  virtual void stop() {}
};
 
template <typename T, typename... Args>
AlgorithmSpec adaptFromTask(Args&&... args)
{
  return AlgorithmSpec::InitCallback{[=](InitContext& ic) {
    auto task = std::make_shared<T>(args...);
    if constexpr (requires { &T::endOfStream; }) {
      auto& callbacks = ic.services().get<CallbackService>();
      callbacks.set<CallbackService::Id::EndOfStream>([task](EndOfStreamContext& eosContext) {
        task->endOfStream(eosContext);
      });
    }
    if constexpr (requires { &T::finaliseCCDB; }) {
      auto& callbacks = ic.services().get<CallbackService>();
      callbacks.set<CallbackService::Id::CCDBDeserialised>([task](ConcreteDataMatcher& matcher, void* obj) {
        task->finaliseCCDB(matcher, obj);
      });
    }
    if constexpr (requires { &T::stop; }) {
      auto& callbacks = ic.services().get<CallbackService>();
      callbacks.set<CallbackService::Id::Stop>([task]() {
        task->stop();
      });
    }
    task->init(ic);
    return [task](ProcessingContext& pc) {
      task->run(pc);
    };
  }};
}
 
template <typename T>
AlgorithmSpec adoptTask(std::shared_ptr<T> task)
{
  return AlgorithmSpec::InitCallback{[task](InitContext& ic) {
    if constexpr (requires { &T::endOfStream; }) {
      auto& callbacks = ic.services().get<CallbackService>();
      callbacks.set<CallbackService::Id::EndOfStream>([task](EndOfStreamContext& eosContext) {
        task->endOfStream(eosContext);
      });
    }
    if constexpr (requires { &T::finaliseCCDB; }) {
      auto& callbacks = ic.services().get<CallbackService>();
      callbacks.set<CallbackService::Id::CCDBDeserialised>([task](ConcreteDataMatcher& matcher, void* obj) {
        task->finaliseCCDB(matcher, obj);
      });
    }
    if constexpr (requires { &T::stop; }) {
      auto& callbacks = ic.services().get<CallbackService>();
      callbacks.set<CallbackService::Id::Stop>([task]() {
        task->stop();
      });
    }
    task->init(ic);
    return [&task](ProcessingContext& pc) {
      task->run(pc);
    };
  }};
}
} // namespace o2::framework
#endif // O2_FRAMEWORK_TASK_H_