include/GaudiKernel/IAlgContextSvc.h

0001 /***********************************************************************************\
0002 * (c) Copyright 1998-2019 CERN for the benefit of the LHCb and ATLAS collaborations *
0003 *                                                                                   *
0004 * This software is distributed under the terms of the Apache version 2 licence,     *
0005 * copied verbatim in the file "LICENSE".                                            *
0006 *                                                                                   *
0007 * In applying this licence, CERN does not waive the privileges and immunities       *
0008 * granted to it by virtue of its status as an Intergovernmental Organization        *
0009 * or submit itself to any jurisdiction.                                             *
0010 \***********************************************************************************/
0011 #ifndef GAUDIKERNEL_IALGCONTEXTSVC_H
0012 #define GAUDIKERNEL_IALGCONTEXTSVC_H
0013 // ============================================================================
0014 // Include files:
0015 // ============================================================================
0016 // STD & STL
0017 // ============================================================================
0018 #include <vector>
0019 // ============================================================================
0020 // GaudiKernel
0021 // ============================================================================
0022 #include "GaudiKernel/EventContext.h"
0023 #include "GaudiKernel/IAlgorithm.h"
0024 #include "GaudiKernel/IInterface.h"
0025 #include "GaudiKernel/SmartIF.h"
0026 // ============================================================================
0027 /** @class IAlgContextSvc
0028  *  An abstract interface for Algorithm Context Service
0029  *  @author ATLAS Collaboration
0030  *  @author Vanya BELYAEV ibelyaev@physics.syr.edu
0031  *  @date 2007-03-07 (modified)
0032  */
0033 class GAUDI_API IAlgContextSvc : virtual public IInterface {
0034 public:
0035   /// InterfaceID
0036   DeclareInterfaceID( IAlgContextSvc, 4, 0 );
0037   /// the actual type of algorithm' stack
0038   typedef std::vector<IAlgorithm*> Algorithms;
0039
0040 public:
0041   /// set     the currently executing algorithm  ("push_back")
0042   virtual StatusCode setCurrentAlg( IAlgorithm* a, const EventContext& context ) = 0;
0043   /// remove the algorithm                       ("pop_back")
0044   virtual StatusCode unSetCurrentAlg( IAlgorithm* a, const EventContext& context ) = 0;
0045   /// accessor to current algorithm:
0046   virtual IAlgorithm* currentAlg() const = 0;
0047   /// get the stack of executed algorithms
0048   virtual const Algorithms& algorithms() const = 0;
0049 };
0050 // ============================================================================
0051 namespace Gaudi {
0052   namespace Utils {
0053     /** @class AlgContext
0054      *  Helper "sentry" class to automatize the safe register/unregister
0055      *  the algorithm's context
0056      *
0057      *  Typical explicit usage:
0058      *
0059      *  @code
0060      *
0061      *   StatusCode MyAlg::execute()
0062      *    {
0063      *       IAlgContextSvc* acs = ... ;
0064      *       // define the context
0065      *       Gaudi::Utils::AlgContext sentry ( this , acs ) ;
0066      *
0067      *       ...
0068      *
0069      *       return StatusCode::SUCCESS ;
0070      *    }
0071      *
0072      *  @endcode
0073      *
0074      *  Note: for the regular job the context is properly
0075      *  defined with the help of corresponding auditor
0076      *  AlgContextAuditor. This helper class is needed only
0077      *  if one needs to ensure that the algorithm must register
0078      *  its context independently on job/auditor configuration
0079      *
0080      *  @see AlgContextAuditor
0081      *  @author Vanya BELYAEV ibelyaev@phys.syr.edu
0082      *  @date   2007-03-07
0083      */
0084     class GAUDI_API AlgContext final {
0085     public:
0086       /** constructor from the service and the algorithm
0087        *  Internally invokes IAlgContextSvc::setCurrentAlg
0088        *  @see IAlgorithm
0089        *  @see IAlgContextSvc
0090        *  @param alg pointer to the current algorithm
0091        *  @param svc pointer to algorithm context service
0092        *  @param context current event context
0093        */
0094       AlgContext( IAlgorithm* alg, IAlgContextSvc* svc, const EventContext& context );
0095
0096       /** constructor from the service and the algorithm (single thread case)
0097        *  Internally invokes IAlgContextSvc::setCurrentAlg
0098        *  @see IAlgorithm
0099        *  @see IAlgContextSvc
0100        *  @param alg pointer to the current algorithm
0101        *  @param svc pointer to algorithm context service
0102        */
0103       AlgContext( IAlgorithm* alg, IAlgContextSvc* svc );
0104
0105       /// Prevent use of temporary EventContext as current context.
0106       /// @see [gaudi/Gaudi#73](https://gitlab.cern.ch/gaudi/Gaudi/issues/73)
0107       AlgContext( IAlgorithm* alg, IAlgContextSvc* svc, EventContext&& context ) = delete;
0108
0109       /** destructor
0110        *  Internally invokes IAlgContextSvc::unSetCurrentAlg
0111        *  @see IAlgorithm
0112        *  @see IAlgContextSvc
0113        */
0114       ~AlgContext();
0115
0116     private:
0117       // copy constructor is disabled
0118       AlgContext( const AlgContext& right ) = delete;
0119       // assignement operator is disabled
0120       AlgContext& operator=( const AlgContext& right ) = delete;
0121
0122     private:
0123       SmartIF<IAlgContextSvc> m_svc;
0124       SmartIF<IAlgorithm>     m_alg;
0125       const EventContext&     m_context;
0126     };
0127   } // namespace Utils
0128 } // end of namespace Gaudi
0129
0130 #endif