SharedResourcePointer< SharedObjectType > Class Template Reference
juce_core » memory

A smart-pointer that automatically creates and manages the lifetime of a shared static instance of a class. More...

## Public Member Functions

| SharedResourcePointer ()
| Creates an instance of the shared object. More...
| SharedResourcePointer (const SharedResourcePointer &)
| ~SharedResourcePointer ()
| Destructor. More...
| operator SharedObjectType * () const noexcept
| Returns the shared object. More...
SharedObjectType & | get () const noexcept
| Returns the shared object. More...
SharedObjectType & | getObject () const noexcept
| Returns the object that this pointer references. More...
SharedObjectType * | operator-> () const noexcept
| Returns the shared object. More...
int | getReferenceCount () const noexcept
| Returns the number of SharedResourcePointers that are currently holding the shared object. More...

## Detailed Description

### template<typename SharedObjectType>
class SharedResourcePointer< SharedObjectType >

A smart-pointer that automatically creates and manages the lifetime of a shared static instance of a class.

The SharedObjectType template type indicates the class to use for the shared object - the only requirements on this class are that it must have a public default constructor and destructor.

The SharedResourcePointer offers a pattern that differs from using a singleton or static instance of an object, because it uses reference-counting to make sure that the underlying shared object is automatically created/destroyed according to the number of SharedResourcePointer objects that exist. When the last one is deleted, the underlying object is also immediately destroyed. This allows you to use scoping to manage the lifetime of a shared resource.

Note: The construction/deletion of the shared object must not involve any code that makes recursive calls to a SharedResourcePointer, or you'll cause a deadlock.

Example:

// An example of a class that contains the shared data you want to use.
struct MySharedData
{
// There's no need to ever create an instance of this class directly yourself,
// but it does need a public constructor that does the initialisation.
MySharedData()
{
sharedStuff = generateHeavyweightStuff();
}
Array<SomeKindOfData> sharedStuff;
};
struct DataUserClass
{
DataUserClass()
{
// Multiple instances of the DataUserClass will all have the same
// shared common instance of MySharedData referenced by their sharedData
// member variables.
useSharedStuff (sharedData->sharedStuff);
}
// By keeping this pointer as a member variable, the shared resource
// is guaranteed to be available for as long as the DataUserClass object.
SharedResourcePointer<MySharedData> sharedData;
};

## Constructor & Destructor Documentation

## SharedResourcePointer() [1/2]

template<typename SharedObjectType>

SharedResourcePointer< SharedObjectType >::SharedResourcePointer | ( |  | ) |

Creates an instance of the shared object.

If other SharedResourcePointer objects for this type already exist, then this one will simply point to the same shared object that they are already using. Otherwise, if this is the first SharedResourcePointer to be created, then a shared object will be created automatically.

## SharedResourcePointer() [2/2]

template<typename SharedObjectType>

SharedResourcePointer< SharedObjectType >::SharedResourcePointer | ( | const SharedResourcePointer< SharedObjectType > & |  | ) |

## ~SharedResourcePointer()

template<typename SharedObjectType>

SharedResourcePointer< SharedObjectType >::~SharedResourcePointer | ( |  | ) |

Destructor.

If no other SharedResourcePointer objects exist, this will also delete the shared object to which it refers.

## Member Function Documentation

## operator SharedObjectType *()

template<typename SharedObjectType>

SharedResourcePointer< SharedObjectType >::operator SharedObjectType * | ( |  | ) | const

noexcept

Returns the shared object.

## get()

template<typename SharedObjectType>

SharedObjectType& SharedResourcePointer< SharedObjectType >::get | ( |  | ) | const

noexcept

Returns the shared object.

## getObject()

template<typename SharedObjectType>

SharedObjectType& SharedResourcePointer< SharedObjectType >::getObject | ( |  | ) | const

noexcept

Returns the object that this pointer references.

The pointer returned may be a nullptr, of course.

## operator->()

template<typename SharedObjectType>

SharedObjectType* SharedResourcePointer< SharedObjectType >::operator-> | ( |  | ) | const

noexcept

Returns the shared object.

## getReferenceCount()

template<typename SharedObjectType>

int SharedResourcePointer< SharedObjectType >::getReferenceCount | ( |  | ) | const

noexcept

Returns the number of SharedResourcePointers that are currently holding the shared object.

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

- juce_SharedResourcePointer.h

Array
Holds a resizable array of primitive or copy-by-value objects.
Definition: juce_Array.h:56
SharedResourcePointer
A smart-pointer that automatically creates and manages the lifetime of a shared static instance of a ...
Definition: juce_SharedResourcePointer.h:82