wxWidgets/interface/wx/any.h
Vadim Zeitlin 3f66f6a5b3 Remove all lines containing cvs/svn "$Id$" keyword.
This keyword is not expanded by Git which means it's not replaced with the
correct revision value in the releases made using git-based scripts and it's
confusing to have lines with unexpanded "$Id$" in the released files. As
expanding them with Git is not that simple (it could be done with git archive
and export-subst attribute) and there are not many benefits in having them in
the first place, just remove all these lines.

If nothing else, this will make an eventual transition to Git simpler.

Closes #14487.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74602 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
2013-07-26 16:02:46 +00:00

449 lines
14 KiB
Objective-C

/////////////////////////////////////////////////////////////////////////////
// Name: any.h
// Purpose: interface of wxAny
// Author: wxWidgets team
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
/**
@class wxAny
The wxAny class represents a container for any type. Its value
can be changed at run time, possibly to a different type of value.
wxAny is a backwards-incompatible (but convertible) successor class for
wxVariant, essentially doing the same thing in a more modern, template-
based manner and with transparent support for any user data type.
Some pseudo-code'ish example of use with arbitrary user data:
@code
void SomeFunction()
{
MyClass myObject;
wxAny any = myObject;
// Do something
// ...
// Let's do a sanity check to make sure that any still holds
// data of correct type.
if ( any.CheckType<MyClass>() )
{
// Thank goodness, still a correct type.
MyClass myObject2 = any.As<MyClass>();
}
else
{
// Something has gone horribly wrong!
wxFAIL();
}
}
@endcode
When compared to wxVariant, there are various internal implementation
differences as well. For instance, wxAny only allocates separate data
object in heap for large objects (i.e. ones with size more than
WX_ANY_VALUE_BUFFER_SIZE, which at the time of writing is 16 bytes).
@note When performing conversions between strings and floating point
numbers, the representation of numbers in C locale is always used.
I.e. @code wxAny("1.23").GetAs<double>() @endcode will always work,
even if the current locale uses comma as decimal separator.
@library{wxbase}
@category{data}
@see wxAnyValueType, wxVariant, @ref overview_cpp_rtti_disabled
*/
class wxAny
{
public:
/**
Default constructor. It seeds the object with a null value.
*/
wxAny();
/**
Constructs wxAny from data.
*/
template<typename T>
wxAny(const T& value);
/**
Constructs wxAny from another wxAny.
*/
wxAny(const wxAny& any);
/**
Constructs wxAny, converting value from wxVariant.
@remarks Because of this conversion, it is not usually possible to
have wxAny that actually holds a wxVariant. If wxVariant
cannot be converted to a specific data type, wxAny will then
hold and manage reference to wxVariantData* similar to how
wxVariant does.
*/
wxAny(const wxVariant& variant);
/**
Destructor.
*/
~wxAny();
/**
This template function converts wxAny into given type. In most cases
no type conversion is performed, so if the type is incorrect an
assertion failure will occur.
@remarks For conveniency, conversion is done when T is wxString. This
is useful when a string literal (which are treated as
const char* and const wchar_t*) has been assigned to wxAny.
This template function may not work properly with Visual C++
6. For full compiler compatibility, please use
wxANY_AS(any, T) macro instead.
*/
template<typename T>
T As() const;
/**
Use this template function for checking if this wxAny holds
a specific C++ data type.
@remarks This template function may not work properly with Visual C++
6. For full compiler compatibility, please use
wxANY_CHECK_TYPE(any, T) macro instead.
@see wxAnyValueType::CheckType()
*/
template<typename T>
bool CheckType() const;
/**
Template function that retrieves and converts the value of this
wxAny to the type that T* value is.
@return Returns @true if conversion was successful.
*/
template<typename T>
bool GetAs(T* value) const;
/**
Specialization of GetAs() that allows conversion of wxAny into
wxVariant.
@return Returns @true if conversion was successful. Conversion usually
only fails if variant used custom wxVariantData that did not
implement the wxAny to wxVariant conversion functions.
*/
bool GetAs(wxVariant* value) const;
/**
Returns the value type as wxAnyValueType instance.
@remarks You cannot reliably test whether two wxAnys are of
same value type by simply comparing return values
of wxAny::GetType(). Instead, use wxAny::HasSameType().
@see HasSameType()
*/
const wxAnyValueType* GetType() const;
/**
Returns @true if this and another wxAny have the same
value type.
*/
bool HasSameType(const wxAny& other) const;
/**
Tests if wxAny is null (that is, whether there is no data).
*/
bool IsNull() const;
/**
Makes wxAny null (that is, clears it).
*/
void MakeNull();
//@{
/**
@name Assignment operators
*/
template<typename T>
wxAny& operator=(const T &value);
wxAny& operator=(const wxAny &any);
wxAny& operator=(const wxVariant &variant);
//@}
//@{
/**
@name Equality operators
@remarks Generic template-based comparison operators have not been
provided for various code consistency reasons, so for custom
data types you have do something like this:
@code
if ( any.CheckType<MyClass*>() &&
any.As<MyClass*>() == myObjectPtr )
{
// Do something if any stores myObjectPtr
}
@endcode
*/
bool operator==(signed char value) const;
bool operator==(signed short value) const;
bool operator==(signed int value) const;
bool operator==(signed long value) const;
bool operator==(wxLongLong_t value) const;
bool operator==(unsigned char value) const;
bool operator==(unsigned short value) const;
bool operator==(unsigned int value) const;
bool operator==(unsigned long value) const;
bool operator==(wxULongLong_t value) const;
bool operator==(float value) const;
bool operator==(double value) const;
bool operator==(bool value) const;
bool operator==(const char* value) const;
bool operator==(const wchar_t* value) const;
bool operator==(const wxString& value) const;
//@}
//@{
/**
@name Inequality operators
*/
bool operator!=(signed char value) const;
bool operator!=(signed short value) const;
bool operator!=(signed int value) const;
bool operator!=(signed long value) const;
bool operator!=(wxLongLong_t value) const;
bool operator!=(unsigned char value) const;
bool operator!=(unsigned short value) const;
bool operator!=(unsigned int value) const;
bool operator!=(unsigned long value) const;
bool operator!=(wxULongLong_t value) const;
bool operator!=(float value) const;
bool operator!=(double value) const;
bool operator!=(bool value) const;
bool operator!=(const char* value) const;
bool operator!=(const wchar_t* value) const;
bool operator!=(const wxString& value) const;
//@}
};
/**
This is value getter macro that is more compatible with older
compilers, such as Visual C++ 6.0.
*/
#define wxANY_AS(any, T)
/**
This is type checking macro that is more compatible with older
compilers, such as Visual C++ 6.0.
*/
#define wxANY_CHECK_TYPE(any, T)
/**
Size of the wxAny value buffer.
*/
enum
{
WX_ANY_VALUE_BUFFER_SIZE = 16
};
/**
Type for buffer within wxAny for holding data.
*/
union wxAnyValueBuffer
{
void* m_ptr;
wxByte m_buffer[WX_ANY_VALUE_BUFFER_SIZE];
};
/**
@class wxAnyValueType
wxAnyValueType is base class for value type functionality for C++ data
types used with wxAny. Usually the default template will create a
satisfactory wxAnyValueType implementation for a data type, but
sometimes you may need to add some customization. To do this you will need
to add specialized template of wxAnyValueTypeImpl<>. Often your only
need may be to add dynamic type conversion which would be done like
this:
@code
template<>
class wxAnyValueTypeImpl<MyClass> :
public wxAnyValueTypeImplBase<MyClass>
{
WX_DECLARE_ANY_VALUE_TYPE(wxAnyValueTypeImpl<MyClass>)
public:
wxAnyValueTypeImpl() :
wxAnyValueTypeImplBase<MyClass>() { }
virtual ~wxAnyValueTypeImpl() { }
virtual bool ConvertValue(const wxAnyValueBuffer& src,
wxAnyValueType* dstType,
wxAnyValueBuffer& dst) const
{
// GetValue() is a static member function implemented
// in wxAnyValueTypeImplBase<>.
MyClass value = GetValue(src);
// TODO: Convert value from src buffer to destination
// type and buffer. If cannot be done, return
// false. This is a simple sample.
if ( dstType->CheckType<wxString>() )
{
wxString s = value.ToString();
wxAnyValueTypeImpl<wxString>::SetValue(s, dst);
}
else
{
return false;
}
}
};
//
// Following must be placed somewhere in your source code
WX_IMPLEMENT_ANY_VALUE_TYPE(wxAnyValueTypeImpl<MyClass>)
@endcode
wxAnyValueTypeImplBase<> template, from which we inherit in the above
example, contains the bulk of the default wxAnyValueTypeImpl<> template
implementation, and as such allows you to easily add some minor
customization.
If you need a have complete control over the type interpretation, you
will need to derive a class directly from wxAnyValueType, like this:
@code
template <>
class wxAnyValueTypeImpl<MyClass> : public wxAnyValueType
{
WX_DECLARE_ANY_VALUE_TYPE(wxAnyValueTypeImpl<MyClass>)
public:
virtual void DeleteValue(wxAnyValueBuffer& buf) const
{
// TODO: Free the data in buffer
// It is important to clear the buffer like this
// at the end of DeleteValue().
buf.m_ptr = NULL;
}
virtual void CopyBuffer(const wxAnyValueBuffer& src,
wxAnyValueBuffer& dst) const
{
// TODO: Copy value from one buffer to another.
// dst is already uninitialized and does not
// need to be freed.
}
virtual bool ConvertValue(const wxAnyValueBuffer& src,
wxAnyValueType* dstType,
wxAnyValueBuffer& dst) const
{
// TODO: Convert value from src buffer to destination
// type and buffer.
}
//
// Following static functions must be implemented
//
static void SetValue(const T& value,
wxAnyValueBuffer& buf)
{
// TODO: Store value into buf.
}
static const T& GetValue(const wxAnyValueBuffer& buf)
{
// TODO: Return reference to value stored in buffer.
}
};
//
// Following must be placed somewhere in your source code
WX_IMPLEMENT_ANY_VALUE_TYPE(wxAnyValueTypeImpl<MyClass>)
@endcode
@library{wxbase}
@category{data}
@see wxAny
*/
class wxAnyValueType
{
public:
/**
Default constructor.
*/
wxAnyValueType();
/**
Destructor.
*/
virtual ~wxAnyValueType();
/**
Use this template function for checking if wxAnyValueType represents
a specific C++ data type.
@remarks This template function does not work on some older compilers
(such as Visual C++ 6.0). For full compiler compatibility
please use wxANY_VALUE_TYPE_CHECK_TYPE(valueTypePtr, T) macro
instead.
@see wxAny::CheckType()
*/
template <typename T>
bool CheckType() const;
/**
Convert value into buffer of different type. Return false if
not possible.
*/
virtual bool ConvertValue(const wxAnyValueBuffer& src,
wxAnyValueType* dstType,
wxAnyValueBuffer& dst) const = 0;
/**
Implement this for buffer-to-buffer copy.
@param src
This is the source data buffer.
@param dst
This is the destination data buffer that is in either
uninitialized or freed state.
*/
virtual void CopyBuffer(const wxAnyValueBuffer& src,
wxAnyValueBuffer& dst) const = 0;
/**
This function is called every time the data in wxAny
buffer needs to be freed.
*/
virtual void DeleteValue(wxAnyValueBuffer& buf) const = 0;
/**
This function is used for internal type matching.
*/
virtual bool IsSameType(const wxAnyValueType* otherType) const = 0;
};
/**
This is type checking macro that is more compatible with older
compilers, such as Visual C++ 6.0.
*/
#define wxANY_VALUE_TYPE_CHECK_TYPE(valueTypePtr, T)