component.h

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//    Copyright 2022, farm-ng 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.
 
// Copyright (c) farm-ng, inc. All rights reserved.
 
#pragma once
 
#include "farm_ng/core/misc/uri.h"
#include "farm_ng/core/pipeline/context.h"
#include "farm_ng/core/pipeline/input.h"
 
#include <farm_ng/core/logging/logger.h>
#include <farm_ng/core/misc/void.h>
 
#include <typeinfo>
 
namespace farm_ng {
 
/// Transforms identifier to C++ source identifier
///
/// Used for uri on Component templated class
std::string demangleTypeid(std::type_info const &type);
 
/// Parent definition of a farm_ng::Component
class Component {
 public:
  /// Default constructor of a context, it gets its own `io_context`.
  template <class TDerived>
  explicit Component(
      Context const &ctx,
      std::string scheme,
      TDerived * /*unused*/,
      std::string const &path)
      : context_strand_(ctx),
        uri_(
            scheme,
            FARM_FORMAT("[{}]", demangleTypeid(typeid(TDerived))),
            path) {
    static_assert(
        std::is_base_of_v<Component, TDerived>,
        "must be derived from Component");
  }
 
  /// Virtual destructor for component derived classes
  virtual ~Component() = default;
 
  /// Returns the owned ``Context`` by the component.
  [[nodiscard]] Context getContext() const;
 
  /// Returns the owned ``ContextStrand`` by the component.
  [[nodiscard]] ContextStrand getContextStrand() const;
 
  /// Returns the unique uri of the component instance.
  [[nodiscard]] Uri const &uri() const;
 
 protected:
  /// Placeholder for a component reset callback
  virtual void onReset(Void const & /*unused*/) {}
 
 private:
  ContextStrand context_strand_;
  Uri uri_;
};
 
/// Templated ``Input`` constructor
template <class TArg>
Input<TArg>::Input(
    Component const *component,
    std::string const &name,
    std::function<void(TArg)> const &f,
    InputConfig const &config)
    : context_strand_(FARM_UNWRAP(component).getContextStrand()),
      uri_(FARM_UNWRAP(component).uri()),
      config_(config),
      function_(f),
      count_(0) {
  uri_.query = FARM_FORMAT("in={}", name);
}
 
}  // namespace farm_ng