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uobject.h (10859B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
******************************************************************************
*
*   Copyright (C) 2002-2012, International Business Machines
*   Corporation and others.  All Rights Reserved.
*
******************************************************************************
*   file name:  uobject.h
*   encoding:   UTF-8
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2002jun26
*   created by: Markus W. Scherer
*/

#ifndef __UOBJECT_H__
#define __UOBJECT_H__

#include "unicode/utypes.h"

#if U_SHOW_CPLUSPLUS_API

#include "unicode/platform.h"

/**
* \file
* \brief C++ API: Common ICU base class UObject.
*/

/**
* \def U_NO_THROW
*         Since ICU 64, use noexcept instead.
*
*         Previously, define this to define the throw() specification so
*                 certain functions do not throw any exceptions
*
*         UMemory operator new methods should have the throw() specification 
*         appended to them, so that the compiler adds the additional nullptr check 
*         before calling constructors. Without, if <code>operator new</code> returns nullptr the
*         constructor is still called, and if the constructor references member 
*         data, (which it typically does), the result is a segmentation violation.
*
* @stable ICU 4.2. Since ICU 64, Use noexcept instead. See ICU-20422.
*/
#ifndef U_NO_THROW
#define U_NO_THROW noexcept
#endif

/*===========================================================================*/
/* UClassID-based RTTI */
/*===========================================================================*/

/**
* UClassID is used to identify classes without using the compiler's RTTI.
* This was used before C++ compilers consistently supported RTTI.
* ICU 4.6 requires compiler RTTI to be turned on.
*
* Each class hierarchy which needs
* to implement polymorphic clone() or operator==() defines two methods,
* described in detail below.  UClassID values can be compared using
* operator==(). Nothing else should be done with them.
*
* \par
* In class hierarchies that implement "poor man's RTTI",
* each concrete subclass implements getDynamicClassID() in the same way:
*
* \code
*      class Derived {
*      public:
*          virtual UClassID getDynamicClassID() const
*            { return Derived::getStaticClassID(); }
*      }
* \endcode
*
* Each concrete class implements getStaticClassID() as well, which allows
* clients to test for a specific type.
*
* \code
*      class Derived {
*      public:
*          static UClassID U_EXPORT2 getStaticClassID();
*      private:
*          static char fgClassID;
*      }
*
*      // In Derived.cpp:
*      UClassID Derived::getStaticClassID()
*        { return (UClassID)&Derived::fgClassID; }
*      char Derived::fgClassID = 0; // Value is irrelevant
* \endcode
* @stable ICU 2.0
*/
typedef void* UClassID;

U_NAMESPACE_BEGIN

/**
* UMemory is the common ICU base class.
* All other ICU C++ classes are derived from UMemory (starting with ICU 2.4).
*
* This is primarily to make it possible and simple to override the
* C++ memory management by adding new/delete operators to this base class.
*
* To override ALL ICU memory management, including that from plain C code,
* replace the allocation functions declared in cmemory.h
*
* UMemory does not contain any virtual functions.
* Common "boilerplate" functions are defined in UObject.
*
* @stable ICU 2.4
*/
class U_COMMON_API UMemory {
public:

/* test versions for debugging shaper heap memory problems */
#ifdef SHAPER_MEMORY_DEBUG  
   static void * NewArray(int size, int count);
   static void * GrowArray(void * array, int newSize );
   static void   FreeArray(void * array );
#endif

#if U_OVERRIDE_CXX_ALLOCATION
   /**
    * Override for ICU4C C++ memory management.
    * simple, non-class types are allocated using the macros in common/cmemory.h
    * (uprv_malloc(), uprv_free(), uprv_realloc());
    * they or something else could be used here to implement C++ new/delete
    * for ICU4C C++ classes
    * @stable ICU 2.4
    */
   static void * U_EXPORT2 operator new(size_t size) noexcept;

   /**
    * Override for ICU4C C++ memory management.
    * See new().
    * @stable ICU 2.4
    */
   static void * U_EXPORT2 operator new[](size_t size) noexcept;

   /**
    * Override for ICU4C C++ memory management.
    * simple, non-class types are allocated using the macros in common/cmemory.h
    * (uprv_malloc(), uprv_free(), uprv_realloc());
    * they or something else could be used here to implement C++ new/delete
    * for ICU4C C++ classes
    * @stable ICU 2.4
    */
   static void U_EXPORT2 operator delete(void *p) noexcept;

   /**
    * Override for ICU4C C++ memory management.
    * See delete().
    * @stable ICU 2.4
    */
   static void U_EXPORT2 operator delete[](void *p) noexcept;

   /**
    * Override for ICU4C C++ memory management for STL.
    * See new().
    * @stable ICU 2.6
    */
   static inline void * U_EXPORT2 operator new(size_t, void *ptr) noexcept { return ptr; }

   /**
    * Override for ICU4C C++ memory management for STL.
    * See delete().
    * @stable ICU 2.6
    */
   static inline void U_EXPORT2 operator delete(void *, void *) noexcept {}

#if U_HAVE_DEBUG_LOCATION_NEW
   /**
     * This method overrides the MFC debug version of the operator new
     * 
     * @param size   The requested memory size
     * @param file   The file where the allocation was requested
     * @param line   The line where the allocation was requested 
     */ 
   static void * U_EXPORT2 operator new(size_t size, const char* file, int line) noexcept;
   /**
     * This method provides a matching delete for the MFC debug new
     * 
     * @param p      The pointer to the allocated memory
     * @param file   The file where the allocation was requested
     * @param line   The line where the allocation was requested 
     */ 
   static void U_EXPORT2 operator delete(void* p, const char* file, int line) noexcept;
#endif /* U_HAVE_DEBUG_LOCATION_NEW */
#endif /* U_OVERRIDE_CXX_ALLOCATION */

   /*
    * Assignment operator not declared. The compiler will provide one
    * which does nothing since this class does not contain any data members.
    * API/code coverage may show the assignment operator as present and
    * untested - ignore.
    * Subclasses need this assignment operator if they use compiler-provided
    * assignment operators of their own. An alternative to not declaring one
    * here would be to declare and empty-implement a protected or public one.
   UMemory &UMemory::operator=(const UMemory &);
    */
};

/**
* UObject is the common ICU "boilerplate" class.
* UObject inherits UMemory (starting with ICU 2.4),
* and all other public ICU C++ classes
* are derived from UObject (starting with ICU 2.2).
*
* UObject contains common virtual functions, in particular a virtual destructor.
*
* The clone() function is not available in UObject because it is not
* implemented by all ICU classes.
* Many ICU services provide a clone() function for their class trees,
* defined on the service's C++ base class
* (which itself is a subclass of UObject).
*
* @stable ICU 2.2
*/
class U_COMMON_API UObject : public UMemory {
public:
   /**
    * Destructor.
    *
    * @stable ICU 2.2
    */
   virtual ~UObject();

   /**
    * ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class.
    * The base class implementation returns a dummy value.
    *
    * Use compiler RTTI rather than ICU's "poor man's RTTI".
    * Since ICU 4.6, new ICU C++ class hierarchies do not implement "poor man's RTTI".
    *
    * @stable ICU 2.2
    */
   virtual UClassID getDynamicClassID() const;

protected:
   // the following functions are protected to prevent instantiation and
   // direct use of UObject itself

   // default constructor
   // inline UObject() {}

   // copy constructor
   // inline UObject(const UObject &other) {}

#if 0
   // TODO Sometime in the future. Implement operator==().
   // (This comment inserted in 2.2)
   // some or all of the following "boilerplate" functions may be made public
   // in a future ICU4C release when all subclasses implement them

   // assignment operator
   // (not virtual, see "Taligent's Guide to Designing Programs" pp.73..74)
   // commented out because the implementation is the same as a compiler's default
   // UObject &operator=(const UObject &other) { return *this; }

   // comparison operators
   virtual inline bool operator==(const UObject &other) const { return this==&other; }
   inline bool operator!=(const UObject &other) const { return !operator==(other); }

   // clone() commented out from the base class:
   // some compilers do not support co-variant return types
   // (i.e., subclasses would have to return UObject * as well, instead of SubClass *)
   // see also UObject class documentation.
   // virtual UObject *clone() const;
#endif

   /*
    * Assignment operator not declared. The compiler will provide one
    * which does nothing since this class does not contain any data members.
    * API/code coverage may show the assignment operator as present and
    * untested - ignore.
    * Subclasses need this assignment operator if they use compiler-provided
    * assignment operators of their own. An alternative to not declaring one
    * here would be to declare and empty-implement a protected or public one.
   UObject &UObject::operator=(const UObject &);
    */
};

#ifndef U_HIDE_INTERNAL_API
/**
* This is a simple macro to add ICU RTTI to an ICU object implementation.
* This does not go into the header. This should only be used in *.cpp files.
*
* @param myClass The name of the class that needs RTTI defined.
* @internal
*/
#define UOBJECT_DEFINE_RTTI_IMPLEMENTATION(myClass) \
   UClassID U_EXPORT2 myClass::getStaticClassID() { \
       static char classID = 0; \
       return (UClassID)&classID; \
   } \
   UClassID myClass::getDynamicClassID() const \
   { return myClass::getStaticClassID(); }


/**
* This macro adds ICU RTTI to an ICU abstract class implementation.
* This macro should be invoked in *.cpp files.  The corresponding
* header should declare getStaticClassID.
*
* @param myClass The name of the class that needs RTTI defined.
* @internal
*/
#define UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(myClass) \
   UClassID U_EXPORT2 myClass::getStaticClassID() { \
       static char classID = 0; \
       return (UClassID)&classID; \
   }

#endif  /* U_HIDE_INTERNAL_API */

U_NAMESPACE_END

#endif /* U_SHOW_CPLUSPLUS_API */

#endif