CommonMessaging.h

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* (c) Copyright 1998-2025 CERN for the benefit of the LHCb and ATLAS collaborations *
*                                                                                   *
* This software is distributed under the terms of the Apache version 2 licence,     *
* copied verbatim in the file "LICENSE".                                            *
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/*
 * CommonMessaging.h
 *
 *  Created on: Feb 20, 2009
 *      Author: Marco Clemencic
 */
 
#pragma once
#include <GaudiKernel/GaudiException.h>
#include <GaudiKernel/IMessageSvc.h>
#include <GaudiKernel/IService.h>
#include <GaudiKernel/ISvcLocator.h>
#include <GaudiKernel/MsgStream.h>
#include <GaudiKernel/SmartIF.h>
#include <boost/thread/tss.hpp>
 
#include <string>
#include <utility>

 
namespace implementation_detail {
 
  template <typename T>
  concept has_name = requires( T const& t ) { t.name(); };
 
  template <typename T>
  concept has_serviceLocator = requires( T const& t ) { t.serviceLocator(); };
 
  template <typename Base>
  struct add_name : Base {
    using Base::Base;
    virtual ~add_name()                     = default;
    virtual const std::string& name() const = 0;
  };
 
  template <typename Base>
  struct add_serviceLocator : Base {
    using Base::Base;
    virtual ~add_serviceLocator()                        = default;
    virtual SmartIF<ISvcLocator>& serviceLocator() const = 0;
  };
} // namespace implementation_detail
 
template <typename Base>
using add_name = std::conditional_t<implementation_detail::has_name<Base>, Base, implementation_detail::add_name<Base>>;
 
template <typename Base>
using add_serviceLocator = std::conditional_t<implementation_detail::has_serviceLocator<Base>, Base,
                                              implementation_detail::add_serviceLocator<Base>>;
 
template <typename Base>
class CommonMessaging;
 
class CommonMessagingBase {
public:
  virtual ~CommonMessagingBase() = default;
  virtual void create_msgStream() const = 0;

  const SmartIF<IMessageSvc>& msgSvc() const { return m_msgsvc; }

  MsgStream& msgStream() const {
    if ( !m_msgStream.get() ) create_msgStream();
    return *m_msgStream;
  }

  MsgStream& msgStream( const MSG::Level level ) const { return msgStream() << level; }

  MsgStream& always() const { return msgStream( MSG::ALWAYS ); }

  MsgStream& fatal() const { return msgStream( MSG::FATAL ); }

  MsgStream& err() const { return msgStream( MSG::ERROR ); }

  MsgStream& error() const { return msgStream( MSG::ERROR ); }

  MsgStream& warning() const { return msgStream( MSG::WARNING ); }

  MsgStream& info() const { return msgStream( MSG::INFO ); }

  MsgStream& debug() const { return msgStream( MSG::DEBUG ); }

  MsgStream& verbose() const { return msgStream( MSG::VERBOSE ); }

  MsgStream& msg() const { return msgStream( MSG::INFO ); }
 
private:
  template <typename Base>
  friend class CommonMessaging;
 
  mutable bool       m_commonMessagingReady = false;
  mutable MSG::Level m_level                = MSG::NIL;

  mutable boost::thread_specific_ptr<MsgStream> m_msgStream;

  mutable SmartIF<IMessageSvc> m_msgsvc;
};
 
template <typename BASE>
class GAUDI_API CommonMessaging : public add_serviceLocator<add_name<BASE>>, public CommonMessagingBase {
public:
  using base_class = CommonMessaging;

  using add_serviceLocator<add_name<BASE>>::add_serviceLocator;

  MSG::Level msgLevel() const {
    if ( m_commonMessagingReady ) return m_level;
    return setUpMessaging();
  }

  bool msgLevel( MSG::Level lvl ) const { return msgLevel() <= lvl; }
 
private:
  // out-of-line 'cold' functions -- put here so as to not blow up the inline 'hot' functions
  void create_msgStream() const override final { m_msgStream.reset( new MsgStream( msgSvc(), this->name() ) ); }

  void initMessaging() const {
    if ( !m_msgsvc ) {
      // Get default implementation of the message service.
      m_msgsvc = this->serviceLocator();
    }
    create_msgStream();
    m_level = MSG::Level( m_msgStream.get() ? m_msgStream->level() : MSG::NIL );
    // if we could not get a MessageSvc, we should try again the initial set up
    m_commonMessagingReady = m_msgsvc;
  }
 
protected:
  MSG::Level setUpMessaging() const {
    if ( !m_commonMessagingReady ) { initMessaging(); }
    return m_level;
  }

  MSG::Level resetMessaging() {
    m_commonMessagingReady = false;
    return setUpMessaging();
  }

  void updateMsgStreamOutputLevel( int level ) {
    setUpMessaging();
    if ( level != MSG::NIL && level != m_level ) {
      if ( msgSvc() ) msgSvc()->setOutputLevel( this->name(), level );
      if ( m_msgStream.get() ) m_msgStream->setLevel( level );
      if ( MSG::Level( level ) <= MSG::DEBUG )
        debug() << "Property update for OutputLevel : new value = " << level << endmsg;
      m_level = MSG::Level( level );
    }
  }
};