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// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h
#ifndef __I_IREFERENCE_COUNTED_H_INCLUDED__
#define __I_IREFERENCE_COUNTED_H_INCLUDED__
#include "irrTypes.h"
namespace irr
{
//! Base class of most objects of the Irrlicht Engine.
/** This class provides reference counting through the methods grab() and drop().
It also is able to store a debug string for every instance of an object.
Most objects of the Irrlicht
Engine are derived from IReferenceCounted, and so they are reference counted.
When you create an object in the Irrlicht engine, calling a method
which starts with 'create', an object is created, and you get a pointer
to the new object. If you no longer need the object, you have
to call drop(). This will destroy the object, if grab() was not called
in another part of you program, because this part still needs the object.
Note, that you only need to call drop() to the object, if you created it,
and the method had a 'create' in it.
A simple example:
If you want to create a texture, you may want to call an imaginable method
IDriver::createTexture. You call
ITexture* texture = driver->createTexture(dimension2d<u32>(128, 128));
If you no longer need the texture, call texture->drop().
If you want to load a texture, you may want to call imaginable method
IDriver::loadTexture. You do this like
ITexture* texture = driver->loadTexture("example.jpg");
You will not have to drop the pointer to the loaded texture, because
the name of the method does not start with 'create'. The texture
is stored somewhere by the driver.
*/
class IReferenceCounted
{
public:
//! Constructor.
IReferenceCounted()
: DebugName(0), ReferenceCounter(1)
{
}
//! Destructor.
virtual ~IReferenceCounted()
{
}
//! Grabs the object. Increments the reference counter by one.
/** Someone who calls grab() to an object, should later also
call drop() to it. If an object never gets as much drop() as
grab() calls, it will never be destroyed. The
IReferenceCounted class provides a basic reference counting
mechanism with its methods grab() and drop(). Most objects of
the Irrlicht Engine are derived from IReferenceCounted, and so
they are reference counted.
When you create an object in the Irrlicht engine, calling a
method which starts with 'create', an object is created, and
you get a pointer to the new object. If you no longer need the
object, you have to call drop(). This will destroy the object,
if grab() was not called in another part of you program,
because this part still needs the object. Note, that you only
need to call drop() to the object, if you created it, and the
method had a 'create' in it.
A simple example:
If you want to create a texture, you may want to call an
imaginable method IDriver::createTexture. You call
ITexture* texture = driver->createTexture(dimension2d<u32>(128, 128));
If you no longer need the texture, call texture->drop().
If you want to load a texture, you may want to call imaginable
method IDriver::loadTexture. You do this like
ITexture* texture = driver->loadTexture("example.jpg");
You will not have to drop the pointer to the loaded texture,
because the name of the method does not start with 'create'.
The texture is stored somewhere by the driver. */
void grab() const { ++ReferenceCounter; }
//! Drops the object. Decrements the reference counter by one.
/** The IReferenceCounted class provides a basic reference
counting mechanism with its methods grab() and drop(). Most
objects of the Irrlicht Engine are derived from
IReferenceCounted, and so they are reference counted.
When you create an object in the Irrlicht engine, calling a
method which starts with 'create', an object is created, and
you get a pointer to the new object. If you no longer need the
object, you have to call drop(). This will destroy the object,
if grab() was not called in another part of you program,
because this part still needs the object. Note, that you only
need to call drop() to the object, if you created it, and the
method had a 'create' in it.
A simple example:
If you want to create a texture, you may want to call an
imaginable method IDriver::createTexture. You call
ITexture* texture = driver->createTexture(dimension2d<u32>(128, 128));
If you no longer need the texture, call texture->drop().
If you want to load a texture, you may want to call imaginable
method IDriver::loadTexture. You do this like
ITexture* texture = driver->loadTexture("example.jpg");
You will not have to drop the pointer to the loaded texture,
because the name of the method does not start with 'create'.
The texture is stored somewhere by the driver.
\return True, if the object was deleted. */
bool drop() const
{
// someone is doing bad reference counting.
_IRR_DEBUG_BREAK_IF(ReferenceCounter <= 0)
--ReferenceCounter;
if (!ReferenceCounter)
{
delete this;
return true;
}
return false;
}
//! Get the reference count.
/** \return Current value of the reference counter. */
s32 getReferenceCount() const
{
return ReferenceCounter;
}
//! Returns the debug name of the object.
/** The Debugname may only be set and changed by the object
itself. This method should only be used in Debug mode.
\return Returns a string, previously set by setDebugName(); */
const c8* getDebugName() const
{
return DebugName;
}
protected:
//! Sets the debug name of the object.
/** The Debugname may only be set and changed by the object
itself. This method should only be used in Debug mode.
\param newName: New debug name to set. */
void setDebugName(const c8* newName)
{
DebugName = newName;
}
private:
//! The debug name.
const c8* DebugName;
//! The reference counter. Mutable to do reference counting on const objects.
mutable s32 ReferenceCounter;
};
} // end namespace irr
#endif
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