itkLoggerThreadWrapper.h

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/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  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
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  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 itkLoggerThreadWrapper_h
#define itkLoggerThreadWrapper_h
 
#include <string>
#include <queue>
#include <thread>
#include <atomic>
 
#include "itkObjectFactory.h"
#include <mutex>
#include "ITKCommonExport.h"
 
namespace itk
{
 
class LoggerThreadWrapperEnums
{
public:
  enum class Operation : uint8_t
  {
    SET_PRIORITY_LEVEL,
    SET_LEVEL_FOR_FLUSHING,
    ADD_LOG_OUTPUT,
    WRITE
  };
};
// Define how to print enumeration
extern ITKCommon_EXPORT std::ostream &
                        operator<<(std::ostream & out, const LoggerThreadWrapperEnums::Operation value);
 
 
template <typename SimpleLoggerType>
class ITK_TEMPLATE_EXPORT LoggerThreadWrapper : public SimpleLoggerType
{
public:
  using Self = LoggerThreadWrapper;
  using Superclass = SimpleLoggerType;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;
 
  itkOverrideGetNameOfClassMacro(LoggerThreadWrapper);
 
  itkNewMacro(Self);
 
  using OutputType = typename SimpleLoggerType::OutputType;
  using PriorityLevelEnum = typename SimpleLoggerType::PriorityLevelEnum;
  using DelayType = unsigned int;
 
  using OperationEnum = LoggerThreadWrapperEnums::Operation;
 
#if !defined(ITK_LEGACY_REMOVE)
  using LoggerThreadWrapperOperationType = OperationEnum;
 
  static constexpr OperationEnum SET_PRIORITY_LEVEL = OperationEnum::SET_PRIORITY_LEVEL;
  static constexpr OperationEnum SET_LEVEL_FOR_FLUSHING = OperationEnum::SET_LEVEL_FOR_FLUSHING;
  static constexpr OperationEnum ADD_LOG_OUTPUT = OperationEnum::ADD_LOG_OUTPUT;
  static constexpr OperationEnum WRITE = OperationEnum::WRITE;
#endif
 
  void
  SetPriorityLevel(PriorityLevelEnum level) override;
 
  PriorityLevelEnum
  GetPriorityLevel() const override;
 
  void
  SetLevelForFlushing(PriorityLevelEnum level) override;
 
  PriorityLevelEnum
  GetLevelForFlushing() const override;
 
  virtual void
  SetDelay(DelayType delay);
 
  virtual DelayType
  GetDelay() const;
 
  void
  AddLogOutput(OutputType * output) override;
 
  void
  Write(PriorityLevelEnum level, std::string const & content) override;
 
  void
  Flush() override;
 
protected:
  void
  PrivateFlush() override;
 
  LoggerThreadWrapper();
 
  ~LoggerThreadWrapper() override;
 
  void
  PrintSelf(std::ostream & os, Indent indent) const override;
 
  void
  ThreadFunction();
 
private:
  std::thread m_Thread{};
 
  std::atomic<bool> m_TerminationRequested{};
 
  std::queue<OperationEnum> m_OperationQ{};
 
  std::queue<std::string> m_MessageQ{};
 
  std::queue<PriorityLevelEnum> m_LevelQ{};
 
  std::queue<typename OutputType::Pointer> m_OutputQ{};
 
  mutable std::mutex m_Mutex{};
 
  DelayType m_Delay{};
 
}; // class LoggerThreadWrapper
 
} // namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkLoggerThreadWrapper.hxx"
#endif
 
#endif // itkLoggerThreadWrapper_h