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ScopedPointer< ObjectType > Class Template Reference

This class holds a pointer which is automatically deleted when this object goes out of scope. More...

Public Member Functions

 ScopedPointer () noexcept
 Creates a ScopedPointer containing a null pointer.
 
 ScopedPointer (ObjectType *const objectToTakePossessionOf) noexcept
 Creates a ScopedPointer that owns the specified object.
 
 ScopedPointer (ScopedPointer &objectToTransferFrom) noexcept
 Creates a ScopedPointer that takes its pointer from another ScopedPointer.
 
 ~ScopedPointer ()
 Destructor.
 
ScopedPointeroperator= (ScopedPointer &objectToTransferFrom)
 Changes this ScopedPointer to point to a new object.
 
ScopedPointeroperator= (ObjectType *const newObjectToTakePossessionOf)
 Changes this ScopedPointer to point to a new object.
 
 operator ObjectType * () const noexcept
 Returns the object that this ScopedPointer refers to.
 
ObjectType * get () const noexcept
 Returns the object that this ScopedPointer refers to.
 
ObjectType & operator* () const noexcept
 Returns the object that this ScopedPointer refers to.
 
ObjectType * operator-> () const noexcept
 Lets you access methods and properties of the object that this ScopedPointer refers to.
 
ObjectType * release () noexcept
 Removes the current object from this ScopedPointer without deleting it.
 
void swapWith (ScopedPointer< ObjectType > &other) noexcept
 Swaps this object with that of another ScopedPointer.
 
ObjectType * createCopy () const
 If the pointer is non-null, this will attempt to return a new copy of the object that is pointed to.
 

Detailed Description

template<class ObjectType>
class ScopedPointer< ObjectType >

This class holds a pointer which is automatically deleted when this object goes out of scope.

Once a pointer has been passed to a ScopedPointer, it will make sure that the pointer gets deleted when the ScopedPointer is deleted. Using the ScopedPointer on the stack or as member variables is a good way to use RAII to avoid accidentally leaking dynamically created objects.

A ScopedPointer can be used in pretty much the same way that you'd use a normal pointer to an object. If you use the assignment operator to assign a different object to a ScopedPointer, the old one will be automatically deleted.

Important note: The class is designed to hold a pointer to an object, NOT to an array! It calls delete on its payload, not delete[], so do not give it an array to hold! For that kind of purpose, you should be using HeapBlock or Array instead.

A const ScopedPointer is guaranteed not to lose ownership of its object or change the object to which it points during its lifetime. This means that making a copy of a const ScopedPointer is impossible, as that would involve the new copy taking ownership from the old one.

If you need to get a pointer out of a ScopedPointer without it being deleted, you can use the release() method.

Something to note is the main difference between this class and the std::auto_ptr class, which is that ScopedPointer provides a cast-to-object operator, wheras std::auto_ptr requires that you always call get() to retrieve the pointer. The advantages of providing the cast is that you don't need to call get(), so can use the ScopedPointer in pretty much exactly the same way as a raw pointer. The disadvantage is that the compiler is free to use the cast in unexpected and sometimes dangerous ways - in particular, it becomes difficult to return a ScopedPointer as the result of a function. To avoid this causing errors, ScopedPointer contains an overloaded constructor that should cause a syntax error in these circumstances, but it does mean that instead of returning a ScopedPointer from a function, you'd need to return a raw pointer (or use a std::auto_ptr instead).

Constructor & Destructor Documentation

template<class ObjectType>
ScopedPointer< ObjectType >::ScopedPointer ( )
noexcept

Creates a ScopedPointer containing a null pointer.

template<class ObjectType>
ScopedPointer< ObjectType >::ScopedPointer ( ObjectType *const  objectToTakePossessionOf)
noexcept

Creates a ScopedPointer that owns the specified object.

template<class ObjectType>
ScopedPointer< ObjectType >::ScopedPointer ( ScopedPointer< ObjectType > &  objectToTransferFrom)
noexcept

Creates a ScopedPointer that takes its pointer from another ScopedPointer.

Because a pointer can only belong to one ScopedPointer, this transfers the pointer from the other object to this one, and the other object is reset to be a null pointer.

template<class ObjectType>
ScopedPointer< ObjectType >::~ScopedPointer ( )

Destructor.

This will delete the object that this ScopedPointer currently refers to.

Member Function Documentation

template<class ObjectType>
ScopedPointer& ScopedPointer< ObjectType >::operator= ( ScopedPointer< ObjectType > &  objectToTransferFrom)

Changes this ScopedPointer to point to a new object.

Because a pointer can only belong to one ScopedPointer, this transfers the pointer from the other object to this one, and the other object is reset to be a null pointer.

If this ScopedPointer already points to an object, that object will first be deleted.

template<class ObjectType>
ScopedPointer& ScopedPointer< ObjectType >::operator= ( ObjectType *const  newObjectToTakePossessionOf)

Changes this ScopedPointer to point to a new object.

If this ScopedPointer already points to an object, that object will first be deleted.

The pointer that you pass in may be a nullptr.

template<class ObjectType>
ScopedPointer< ObjectType >::operator ObjectType * ( ) const
noexcept

Returns the object that this ScopedPointer refers to.

template<class ObjectType>
ObjectType* ScopedPointer< ObjectType >::get ( ) const
noexcept

Returns the object that this ScopedPointer refers to.

template<class ObjectType>
ObjectType& ScopedPointer< ObjectType >::operator* ( ) const
noexcept

Returns the object that this ScopedPointer refers to.

template<class ObjectType>
ObjectType* ScopedPointer< ObjectType >::operator-> ( ) const
noexcept

Lets you access methods and properties of the object that this ScopedPointer refers to.

template<class ObjectType>
ObjectType* ScopedPointer< ObjectType >::release ( )
noexcept

Removes the current object from this ScopedPointer without deleting it.

This will return the current object, and set the ScopedPointer to a null pointer.

Referenced by OwnedArray< MidiBuffer >::set().

template<class ObjectType>
void ScopedPointer< ObjectType >::swapWith ( ScopedPointer< ObjectType > &  other)
noexcept

Swaps this object with that of another ScopedPointer.

The two objects simply exchange their pointers.

template<class ObjectType>
ObjectType* ScopedPointer< ObjectType >::createCopy ( ) const

If the pointer is non-null, this will attempt to return a new copy of the object that is pointed to.

If the pointer is null, this will safely return a nullptr.


The documentation for this class was generated from the following file: