LivenessBroker Class Reference

#include <liveness-broker.h>

Public Member Functions
template<typename T >
bool	IsHeapObjectAlive (const T *object) const
template<typename T >
bool	IsHeapObjectAlive (const WeakMember< T > &weak_member) const
template<typename T >
bool	IsHeapObjectAlive (const UntracedMember< T > &untraced_member) const

Friends
class	internal::LivenessBrokerFactory

Detailed Description

The broker is passed to weak callbacks to allow (temporarily) querying the liveness state of an object. References to non-live objects must be cleared when IsHeapObjectAlive() returns false.

class GCedWithCustomWeakCallback final
  : public GarbageCollected<GCedWithCustomWeakCallback> {
 public:
  UntracedMember<Bar> bar;
 
  void CustomWeakCallbackMethod(const LivenessBroker& broker) {
    if (!broker.IsHeapObjectAlive(bar))
      bar = nullptr;
  }
 
  void Trace(cppgc::Visitor* visitor) const {
    visitor->RegisterWeakCallbackMethod<
        GCedWithCustomWeakCallback,
        &GCedWithCustomWeakCallback::CustomWeakCallbackMethod>(this);
  }
};

Definition at line 43 of file liveness-broker.h.

Member Function Documentation

IsHeapObjectAlive() [1/3]

bool IsHeapObjectAlive ( const T *  object ) const

inline

Definition at line 46 of file liveness-broker.h.

References BasicMember< T, WeaknessTag, WriteBarrierPolicy, CheckingPolicy >::cppgc::TraceTrait.

IsHeapObjectAlive() [2/3]

bool IsHeapObjectAlive ( const UntracedMember< T > &  untraced_member ) const

inline

Definition at line 59 of file liveness-broker.h.

References cppgc::kSentinelPointer.

IsHeapObjectAlive() [3/3]

bool IsHeapObjectAlive ( const WeakMember< T > &  weak_member ) const

inline

Definition at line 53 of file liveness-broker.h.

References cppgc::kSentinelPointer.

Friends And Related Function Documentation

internal::LivenessBrokerFactory

friend class internal::LivenessBrokerFactory

friend

Definition at line 69 of file liveness-broker.h.

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

• include/cppgc/liveness-broker.h