include/opencascade/StdObjMgt_SharedObject.hxx

0001 // Copyright (c) 2015 OPEN CASCADE SAS
0002 //
0003 // This file is part of Open CASCADE Technology software library.
0004 //
0005 // This library is free software; you can redistribute it and/or modify it under
0006 // the terms of the GNU Lesser General Public License version 2.1 as published
0007 // by the Free Software Foundation, with special exception defined in the file
0008 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
0009 // distribution for complete text of the license and disclaimer of any warranty.
0010 //
0011 // Alternatively, this file may be used under the terms of Open CASCADE
0012 // commercial license or contractual agreement.
0013
0014
0015 #ifndef _StdObjMgt_SharedObject_HeaderFile
0016 #define _StdObjMgt_SharedObject_HeaderFile
0017
0018 #include <Standard_NoSuchObject.hxx>
0019 #include <StdObjMgt_Persistent.hxx>
0020
0021 class StdObjMgt_SharedObject
0022 {
0023 public:
0024   template <class Transient>
0025   class AbstractPersistentBase : public Standard_Transient
0026   {
0027   public:
0028     virtual Handle(Transient) Import() const = 0;
0029   };
0030
0031   template <class TransientT, class Base = StdObjMgt_Persistent>
0032   class SharedBase : public Base
0033   {
0034   public:
0035     //! Changes transient object
0036     inline void Transient(const Handle(TransientT)& theTransient)
0037       { myTransient = theTransient; }
0038
0039     //! Import transient object from the persistent data.
0040     inline const Handle(TransientT)& Import()  { return myTransient; }
0041
0042   protected:
0043     Handle(TransientT) myTransient;
0044   };
0045
0046   template <class Base,
0047             class Transient,
0048             class Persistent = AbstractPersistentBase<Transient> >
0049   class DelayedBase : public Base
0050   {
0051   public:
0052     typedef Transient  TransientBase;
0053     typedef Persistent PersistentBase;
0054
0055     //! Import transient object from the persistent data.
0056     virtual Handle(Transient) Import()
0057       { return myTransient; }
0058
0059   public:
0060     Handle(Transient) myTransient;
0061   };
0062
0063   template <class Base,
0064             class PersistentData,
0065             class Transient = typename Base::TransientBase>
0066   class IgnoreData : public Base
0067   {
0068   public:
0069     //! Read persistent data from a file.
0070     virtual void Read (StdObjMgt_ReadData& theReadData)
0071       { PersistentData().Read (theReadData); }
0072     //! Write persistent data to a file.
0073     virtual void Write (StdObjMgt_WriteData& theWriteData) const
0074       { PersistentData().Write (theWriteData); }
0075     //! Gets persistent child objects
0076     virtual void PChildren(StdObjMgt_Persistent::SequenceOfPersistent& theChildren) const
0077       { PersistentData().PChildren(theChildren); }
0078     //! Returns persistent type name
0079     virtual Standard_CString PName() const
0080       { return PersistentData().PName(); }
0081
0082     //! Import transient object from the persistent data.
0083     virtual Handle(Transient) Import()
0084       { return NULL; }
0085   };
0086
0087 private:
0088   template <class Base>
0089   class delayedSubBase : public Base
0090   {
0091   public:
0092     //! Import transient object from the persistent data.
0093     virtual Handle(typename Base::TransientBase) Import()
0094     {
0095       if (Base::myTransient.IsNull() && !myPersistent.IsNull())
0096       {
0097         Base::myTransient = myPersistent->Import();
0098         myPersistent.Nullify();
0099       }
0100
0101       return Base::myTransient;
0102     }
0103
0104   public:
0105     Handle(typename Base::PersistentBase) myPersistent;
0106   };
0107
0108 public:
0109   template <class Base, class Persistent = typename Base::PersistentBase>
0110   class Delayed : public delayedSubBase<Base>
0111   {
0112   private:
0113     template <class T1, class T2>
0114     struct DownCast {
0115       static Handle(T1) make(const Handle(T2)& theT2)
0116         { return Handle(T1)::DownCast(theT2); }
0117     };
0118
0119     template <class T>
0120     struct DownCast<T, T> {
0121       static Handle(T) make(const Handle(T)& theT)
0122         { return theT; }
0123     };
0124
0125   public:
0126     //! Read persistent data from a file.
0127     virtual void Read (StdObjMgt_ReadData& theReadData)
0128     {
0129       Handle(Persistent) aPersistent = new Persistent;
0130       aPersistent->Read (theReadData);
0131       this->myPersistent = aPersistent;
0132     }
0133     //! Write persistent data to a file.
0134     virtual void Write(StdObjMgt_WriteData& theWriteData) const
0135     {
0136       Handle(Persistent) aPersistent =
0137         DownCast<Persistent, typename Base::PersistentBase>::make(this->myPersistent);
0138       Standard_NoSuchObject_Raise_if(aPersistent.IsNull(),
0139         "StdObjMgt_SharedObject::Delayed::Write - persistent object wasn't set for writing!");
0140       aPersistent->Write(theWriteData);
0141     }
0142     //! Gets persistent child objects
0143     virtual void PChildren(StdObjMgt_Persistent::SequenceOfPersistent& theChildren) const
0144     {
0145       Handle(Persistent) aPersistent =
0146         DownCast<Persistent, typename Base::PersistentBase>::make(this->myPersistent);
0147       Standard_NoSuchObject_Raise_if(aPersistent.IsNull(),
0148         "StdObjMgt_SharedObject::Delayed::PChildren - persistent object wasn't set for writing!");
0149       aPersistent->PChildren(theChildren);
0150     }
0151     //! Returns persistent type name
0152     virtual Standard_CString PName() const
0153     {
0154       Handle(Persistent) aPersistent =
0155         DownCast<Persistent, typename Base::PersistentBase>::make(this->myPersistent);
0156       Standard_NoSuchObject_Raise_if(aPersistent.IsNull(),
0157         "StdObjMgt_SharedObject::Delayed::PName - persistent object wasn't set for writing!");
0158       return aPersistent->PName();
0159     }
0160   };
0161 };
0162
0163 #endif