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Diffstat (limited to 'rasodmg/ref.hh')
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diff --git a/rasodmg/ref.hh b/rasodmg/ref.hh new file mode 100644 index 0000000..2b5678e --- /dev/null +++ b/rasodmg/ref.hh @@ -0,0 +1,323 @@ +/* +* This file is part of rasdaman community. +* +* Rasdaman community is free software: you can redistribute it and/or modify +* it under the terms of the GNU General Public License as published by +* the Free Software Foundation, either version 3 of the License, or +* (at your option) any later version. +* +* Rasdaman community is distributed in the hope that it will be useful, +* but WITHOUT ANY WARRANTY; without even the implied warranty of +* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +* GNU General Public License for more details. +* +* You should have received a copy of the GNU General Public License +* along with rasdaman community. If not, see <http://www.gnu.org/licenses/>. +* +* Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 Peter Baumann / +rasdaman GmbH. +* +* For more information please see <http://www.rasdaman.org> +* or contact Peter Baumann via <baumann@rasdaman.com>. +/ +/** + * INCLUDE: ref.hh + * + * MODULE: rasodmg + * CLASS: r_Ref, r_Ref_Any + * + * COMMENTS: + * None +*/ + +#ifndef _D_REF_ +#define _D_REF_ + +#include "raslib/error.hh" +#include "raslib/oid.hh" + +class r_Object; +class r_Point; +class r_Sinterval; +class r_Minterval; +class r_Oid; +class r_Scalar; +class r_Primitive; +class r_Structure; + +//@ManMemo: Module: {\bf rasodmg} + +/** + The class \Ref{r_Ref_Any} is defined to support a reference to any + type. Its primary purpose is to handle generic refernces and allow + conversions of \Ref{r_Ref}s in the type hierarchy. A \Ref{r_Ref_Any} + object can be used as an intermediary between any two types \Ref{r_Ref}<X> + and \Ref{r_Ref}<Y> where X and Y are different types. A \Ref{r_Ref}<T> can + always be converted to a \Ref{r_Ref_Any}; there is a function to perform + the conversion in the \Ref{r_Ref}<T> template. Each \Ref{r_Ref}<T> class + has a constructor and assignment operator that takes a reference to a + \Ref{r_Ref_Any}. +*/ + +class r_Ref_Any +{ + public: + /// default constructor + r_Ref_Any(); + + /// copy constructor + r_Ref_Any( const r_Ref_Any& ); + + /// constructor for creating a reference with an oid + r_Ref_Any( const r_OId& initOId ); + /** + Dereferencing the self object results in loading the object with {\tt initOId}. + */ + + /// constructor getting a pointer to a persistent capable object + r_Ref_Any( r_Object* ); + + /// constructor getting a general pointer + r_Ref_Any( void* ); + + /// destructor deletes referenced object from main memory and database + ~r_Ref_Any(); + + /// assignment operator for assigning a \Ref{r_Ref_Any} pointer + r_Ref_Any& operator=( const r_Ref_Any& ); + + /// assignment operator for assigning a pointer to a persistent capable object + r_Ref_Any& operator=( r_Object* ); + + /// delete from main memory + void destroy(); + + /// deletes referenced object from main memory and database + void delete_object(); + + //@Man: Cast operators: + //@{ + /// + + /// + operator const void*() const; + /// + operator void*(); + /// + operator r_Point*(); + /// + operator r_Sinterval*(); + /// + operator r_Minterval*(); + /// + operator r_OId*(); + /// + operator r_Scalar*(); + /// + operator r_Structure*(); + /// + operator r_Primitive*(); + + /// + //@} + + + /// operator for validity test + int operator!() const; + + /// method for reference validity test + int is_null() const; + /** + The method delivers true iff the oid and/or the memory pointer are valid. + */ + + //@Man: Comparison operators: + //@{ + /// + + /// + int operator==( const r_Ref_Any& ) const; + /// + int operator!=( const r_Ref_Any& ) const; + /// compares the memory pointer (does not load the object) + int operator==( const r_Object* ) const; + /// compares the memory pointer (does not load the object) + int operator!=( const r_Object* ) const; + + /// + //@} + + /// get oid + inline const r_OId& get_oid() const; + + //@Man: Methods for internal use only + //@{ + /// + /// constructor getting oid and memory pointer + r_Ref_Any( const r_OId&, r_Object* ); + /// + inline unsigned int is_oid_valid() const; + /// get memory pointer (without loading the object) + void* get_memory_ptr() const; + /// + //@} + + private: + /// main memory pointer + void* memptr; + + /// object identifier + r_OId oid; +}; + + + + +//@ManMemo: Module: {\bf rasodmg} + +/** + References of type \Ref{r_Ref} in many respects behave like + C++ pointers but provide an additional mechanism that guarantees + integrity in references to persistent objects. \Ref{r_Ref} + implements a so called {\bf smart pointer} which behaves like + a C++ pointer but can do additional things in time of dereferencing + the pointer. In case that no valid memory pointer is available, + which means that the object is not present, and an oid is existing, + the object belonging to the oid is read from the db and the new + memory pointer is given back. +*/ + +template<class T> +class r_Ref +{ + public: + /// default constructor + r_Ref(); + + /// constructor for r_Ref_Any objects + r_Ref( const r_Ref_Any& ); + + /// constructor for creating a reference with an oid + r_Ref( const r_OId& initOId ); + /** + Dereferencing the self object results in loading the object with {\tt initOId}. + */ + + /// copy constructor + r_Ref( const r_Ref<T>& ); + + /// destructor deletes referenced object from main memory and database + ~r_Ref(); + + /// cast to \Ref{r_Ref_Any} + operator r_Ref_Any() const; + + // cast to const \Ref{r_Ref_Any} + // operator const r_Ref_Any() const; + + /// assignment operator for assigning a \Ref{r_Ref_Any} + r_Ref<T>& operator=( const r_Ref_Any& ); + + /// assignment operator for assigning a C pointer + r_Ref<T>& operator=( T* ); + + // assignment operator for assigning a r_Ref pointer + // r_Ref<T>& operator=( r_Ref<T>& ); + + /// assignment operator for assigning a r_Ref pointer + r_Ref<T>& operator=( const r_Ref<T>& ); + + /// dereference operator (error kinds: r_Error_RefNull, r_Error_RefInvalid) + const T& operator*() const throw (r_Error); + + /// dereference operator (error kinds: r_Error_RefNull, r_Error_RefInvalid) + T& operator*() throw( r_Error ); + /** + If the memory pointer is zero and the oid is valid, the object is loaded from the server + and a reference to the object in memory is returned. + */ + + const T* operator->() const throw (r_Error); + + /// operator for dereferencing the reference (error kinds: r_Error_RefNull, r_Error_RefInvalid) + T* operator->() throw( r_Error ); + /** + If the memory pointer is zero and the oid is valid, the object is loaded from the server + and the new memory location is returned. + */ + + const T* ptr() const throw (r_Error); + + /// method for dereferencing the reference (error kinds: r_Error_RefNull, r_Error_RefInvalid) + T* ptr() throw( r_Error ); + /** + If the memory pointer is zero and the oid is valid, the object is loaded from the server + and the new memory location is returned. + */ + + /// operator for validity test + int operator!() const; + + /// method for reference validity test + int is_null() const; + /** + The method delivers true iff the oid and/or the memory pointer are valid. + */ + + //@Man: Comparison operators: + //@{ + /// + + /// + int operator==( const r_Ref<T>& refR ) const; + /// + int operator!=( const r_Ref<T>& refR ) const; + /// compares the memory pointer (does not load the object) + int operator==( const T* ) const; + /// compares the memory pointer (does not load the object) + int operator!=( const T* ) const; + + /// + //@} + + /// delete from main memory + void destroy(); + + /// deletes referenced object from main memory and database + void delete_object(); + + /// get oid + inline const r_OId& get_oid() const; + + //@Man: Methods for internal use only + //@{ + /// + /// constructor getting memory pointer + r_Ref( T* ); + + /// constructor getting oid and memory pointer + r_Ref( const r_OId&, T* ); + + /// get memory pointer (without loading the object) + T* get_memory_ptr() const; + + /// + inline unsigned int is_oid_valid() const; + + /// + //@} + + private: + /// loads an object from database + void load_object() const; + + /// main memory pointer + mutable T* memptr; + + /// object identifier + r_OId oid; +}; + +#include "rasodmg/ref.icc" + +#endif |