juce_ReferenceCountedObject.h

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/*
  ==============================================================================
 
   This file is part of the juce_core module of the JUCE library.
   Copyright (c) 2015 - ROLI Ltd.
 
   Permission to use, copy, modify, and/or distribute this software for any purpose with
   or without fee is hereby granted, provided that the above copyright notice and this
   permission notice appear in all copies.
 
   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN
   NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
   DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
   IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
   ------------------------------------------------------------------------------
 
   NOTE! This permissive ISC license applies ONLY to files within the juce_core module!
   All other JUCE modules are covered by a dual GPL/commercial license, so if you are
   using any other modules, be sure to check that you also comply with their license.
 
   For more details, visit www.juce.com
 
  ==============================================================================
*/
 
#ifndef JUCE_REFERENCECOUNTEDOBJECT_H_INCLUDED
#define JUCE_REFERENCECOUNTEDOBJECT_H_INCLUDED
 
 
//==============================================================================
class JUCE_API  ReferenceCountedObject
{
public:
    //==============================================================================
    void incReferenceCount() noexcept
    {
        ++refCount;
    }
 
    void decReferenceCount() noexcept
    {
        jassert (getReferenceCount() > 0);
 
        if (--refCount == 0)
            delete this;
    }
 
    bool decReferenceCountWithoutDeleting() noexcept
    {
        jassert (getReferenceCount() > 0);
        return --refCount == 0;
    }
 
    int getReferenceCount() const noexcept       { return refCount.get(); }
 
 
protected:
    //==============================================================================
    ReferenceCountedObject() {}
 
    virtual ~ReferenceCountedObject()
    {
        // it's dangerous to delete an object that's still referenced by something else!
        jassert (getReferenceCount() == 0);
    }
 
    void resetReferenceCount() noexcept
    {
        refCount = 0;
    }
 
private:
    //==============================================================================
    Atomic <int> refCount;
 
    friend struct ContainerDeletePolicy<ReferenceCountedObject>;
    JUCE_DECLARE_NON_COPYABLE (ReferenceCountedObject)
};
 
 
//==============================================================================
class JUCE_API  SingleThreadedReferenceCountedObject
{
public:
    //==============================================================================
    void incReferenceCount() noexcept
    {
        ++refCount;
    }
 
    void decReferenceCount() noexcept
    {
        jassert (getReferenceCount() > 0);
 
        if (--refCount == 0)
            delete this;
    }
 
    bool decReferenceCountWithoutDeleting() noexcept
    {
        jassert (getReferenceCount() > 0);
        return --refCount == 0;
    }
 
    int getReferenceCount() const noexcept       { return refCount; }
 
 
protected:
    //==============================================================================
    SingleThreadedReferenceCountedObject() : refCount (0)  {}
 
    virtual ~SingleThreadedReferenceCountedObject()
    {
        // it's dangerous to delete an object that's still referenced by something else!
        jassert (getReferenceCount() == 0);
    }
 
private:
    //==============================================================================
    int refCount;
 
    friend struct ContainerDeletePolicy<ReferenceCountedObject>;
    JUCE_DECLARE_NON_COPYABLE (SingleThreadedReferenceCountedObject)
};
 
 
//==============================================================================
template <class ReferenceCountedObjectClass>
class ReferenceCountedObjectPtr
{
public:
    typedef ReferenceCountedObjectClass ReferencedType;
 
    //==============================================================================
    ReferenceCountedObjectPtr() noexcept
        : referencedObject (nullptr)
    {
    }
 
    ReferenceCountedObjectPtr (ReferencedType* refCountedObject) noexcept
        : referencedObject (refCountedObject)
    {
        incIfNotNull (refCountedObject);
    }
 
    ReferenceCountedObjectPtr (const ReferenceCountedObjectPtr& other) noexcept
        : referencedObject (other.referencedObject)
    {
        incIfNotNull (referencedObject);
    }
 
    template <class Convertible>
    ReferenceCountedObjectPtr (const ReferenceCountedObjectPtr<Convertible>& other) noexcept
        : referencedObject (static_cast <ReferencedType*> (other.get()))
    {
        incIfNotNull (referencedObject);
    }
 
    ReferenceCountedObjectPtr& operator= (const ReferenceCountedObjectPtr& other)
    {
        return operator= (other.referencedObject);
    }
 
    template <class Convertible>
    ReferenceCountedObjectPtr& operator= (const ReferenceCountedObjectPtr<Convertible>& other)
    {
        return operator= (static_cast<ReferencedType*> (other.get()));
    }
 
    ReferenceCountedObjectPtr& operator= (ReferencedType* const newObject)
    {
        if (referencedObject != newObject)
        {
            incIfNotNull (newObject);
            ReferencedType* const oldObject = referencedObject;
            referencedObject = newObject;
            decIfNotNull (oldObject);
        }
 
        return *this;
    }
 
   #if JUCE_COMPILER_SUPPORTS_MOVE_SEMANTICS
 
    ReferenceCountedObjectPtr (ReferenceCountedObjectPtr&& other) noexcept
        : referencedObject (other.referencedObject)
    {
        other.referencedObject = nullptr;
    }
 
    ReferenceCountedObjectPtr& operator= (ReferenceCountedObjectPtr&& other)
    {
        std::swap (referencedObject, other.referencedObject);
        return *this;
    }
   #endif
 
    ~ReferenceCountedObjectPtr()
    {
        decIfNotNull (referencedObject);
    }
 
    //==============================================================================
    operator ReferencedType*() const noexcept       { return referencedObject; }
 
    ReferencedType* get() const noexcept            { return referencedObject; }
 
    ReferencedType* getObject() const noexcept      { return referencedObject; }
 
    // the -> operator is called on the referenced object
    ReferencedType* operator->() const noexcept
    {
        jassert (referencedObject != nullptr); // null pointer method call!
        return referencedObject;
    }
 
private:
    //==============================================================================
    ReferencedType* referencedObject;
 
    static void incIfNotNull (ReferencedType* o) noexcept
    {
        if (o != nullptr)
            o->incReferenceCount();
    }
 
    static void decIfNotNull (ReferencedType* o) noexcept
    {
        if (o != nullptr && o->decReferenceCountWithoutDeleting())
            ContainerDeletePolicy<ReferencedType>::destroy (o);
    }
};
 
 
//==============================================================================
template <class ReferenceCountedObjectClass>
bool operator== (const ReferenceCountedObjectPtr<ReferenceCountedObjectClass>& object1, ReferenceCountedObjectClass* const object2) noexcept
{
    return object1.get() == object2;
}
 
template <class ReferenceCountedObjectClass>
bool operator== (const ReferenceCountedObjectPtr<ReferenceCountedObjectClass>& object1, const ReferenceCountedObjectPtr<ReferenceCountedObjectClass>& object2) noexcept
{
    return object1.get() == object2.get();
}
 
template <class ReferenceCountedObjectClass>
bool operator== (ReferenceCountedObjectClass* object1, const ReferenceCountedObjectPtr<ReferenceCountedObjectClass>& object2) noexcept
{
    return object1 == object2.get();
}
 
template <class ReferenceCountedObjectClass>
bool operator!= (const ReferenceCountedObjectPtr<ReferenceCountedObjectClass>& object1, const ReferenceCountedObjectClass* object2) noexcept
{
    return object1.get() != object2;
}
 
template <class ReferenceCountedObjectClass>
bool operator!= (const ReferenceCountedObjectPtr<ReferenceCountedObjectClass>& object1, const ReferenceCountedObjectPtr<ReferenceCountedObjectClass>& object2) noexcept
{
    return object1.get() != object2.get();
}
 
template <class ReferenceCountedObjectClass>
bool operator!= (ReferenceCountedObjectClass* object1, const ReferenceCountedObjectPtr<ReferenceCountedObjectClass>& object2) noexcept
{
    return object1 != object2.get();
}
 
 
#endif   // JUCE_REFERENCECOUNTEDOBJECT_H_INCLUDED