SkRefCntBase Class Reference

#include <SkRefCnt.h>

Inheritance diagram for SkRefCntBase:

Public Member Functions
	SkRefCntBase ()
virtual	~SkRefCntBase ()
bool	unique () const
void	ref () const
void	unref () const

Private Member Functions
virtual void	internal_dispose () const

Friends
class	SkWeakRefCnt

Detailed Description

SkRefCntBase is the base class for objects that may be shared by multiple objects. When an existing owner wants to share a reference, it calls ref(). When an owner wants to release its reference, it calls unref(). When the shared object's reference count goes to zero as the result of an unref() call, its (virtual) destructor is called. It is an error for the destructor to be called explicitly (or via the object going out of scope on the stack or calling delete) if getRefCnt() > 1.

Definition at line 31 of file SkRefCnt.h.

Constructor & Destructor Documentation

SkRefCntBase()

SkRefCntBase::SkRefCntBase ( )

inline

Default construct, initializing the reference count to 1.

Definition at line 35 of file SkRefCnt.h.

: fRefCnt(1) {}

~SkRefCntBase()

virtual SkRefCntBase::~SkRefCntBase ( )

inlinevirtual

Destruct, asserting that the reference count is 1.

Definition at line 39 of file SkRefCnt.h.

                            {
    #ifdef SK_DEBUG
        SkASSERTF(this->getRefCnt() == 1, "fRefCnt was %d", this->getRefCnt());
        // illegal value, to catch us if we reuse after delete
        fRefCnt.store(0, std::memory_order_relaxed);
    #endif
    }

Member Function Documentation

internal_dispose()

virtual void SkRefCntBase::internal_dispose ( ) const

inlineprivatevirtual

Called when the ref count goes to 0.

Reimplemented in SkWeakRefCnt.

Definition at line 94 of file SkRefCnt.h.

                                          {
    #ifdef SK_DEBUG
        SkASSERT(0 == this->getRefCnt());
        fRefCnt.store(1, std::memory_order_relaxed);
    #endif
        delete this;
    }

ref()

void SkRefCntBase::ref ( ) const

inline

Increment the reference count. Must be balanced by a call to unref().

Definition at line 62 of file SkRefCnt.h.

                     {
        SkASSERT(this->getRefCnt() > 0);
        // No barrier required.
        (void)fRefCnt.fetch_add(+1, std::memory_order_relaxed);
    }

unique()

bool SkRefCntBase::unique ( ) const

inline

May return true if the caller is the only owner. Ensures that all previous owner's actions are complete.

Definition at line 50 of file SkRefCnt.h.

                        {
        if (1 == fRefCnt.load(std::memory_order_acquire)) {
            // The acquire barrier is only really needed if we return true.  It
            // prevents code conditioned on the result of unique() from running
            // until previous owners are all totally done calling unref().
            return true;
        }
        return false;
    }

unref()

void SkRefCntBase::unref ( ) const

inline

Decrement the reference count. If the reference count is 1 before the decrement, then delete the object. Note that if this is the case, then the object needs to have been allocated via new, and not on the stack.

Definition at line 72 of file SkRefCnt.h.

                       {
        SkASSERT(this->getRefCnt() > 0);
        // A release here acts in place of all releases we "should" have been doing in ref().
        if (1 == fRefCnt.fetch_add(-1, std::memory_order_acq_rel)) {
            // Like unique(), the acquire is only needed on success, to make sure
            // code in internal_dispose() doesn't happen before the decrement.
            this->internal_dispose();
        }
    }

Friends And Related Symbol Documentation

SkWeakRefCnt

friend class SkWeakRefCnt

friend

Definition at line 104 of file SkRefCnt.h.

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

• third_party/skia/include/core/SkRefCnt.h