folly::TLRefCount::LocalRefCount Class Reference

Public Member Functions
	LocalRefCount (TLRefCount &refCount)
	~LocalRefCount ()
void	collect ()
bool	operator++ ()
bool	operator-- ()

Private Member Functions
bool	update (Int delta)

Private Attributes
AtomicInt	count_ {0}
TLRefCount &	refCount_
std::mutex	collectMutex_
Int	collectCount_ {0}
std::shared_ptr< void >	collectGuard_

Detailed Description

Definition at line 136 of file TLRefCount.h.

Constructor & Destructor Documentation

folly::TLRefCount::LocalRefCount::LocalRefCount ( TLRefCount &  refCount )

inlineexplicit

Definition at line 138 of file TLRefCount.h.

References folly::TLRefCount::collectGuard_, and folly::TLRefCount::globalMutex_.

                                                 : refCount_(refCount) {
      std::lock_guard<std::mutex> lg(refCount.globalMutex_);

      collectGuard_ = refCount.collectGuard_;
    }

folly::TLRefCount::LocalRefCount::~LocalRefCount ( )

inline

Definition at line 144 of file TLRefCount.h.

References folly::collect().

                     {
      collect();
    }

Member Function Documentation

void folly::TLRefCount::LocalRefCount::collect ( )

inline

Definition at line 148 of file TLRefCount.h.

References folly::TLRefCount::collectGuard_.

                   {
      std::lock_guard<std::mutex> lg(collectMutex_);

      if (!collectGuard_) {
        return;
      }

      collectCount_ = count_.load();
      refCount_.globalCount_.fetch_add(collectCount_);
      collectGuard_.reset();
    }

bool folly::TLRefCount::LocalRefCount::operator++ ( )

inline

Definition at line 160 of file TLRefCount.h.

                      {
      return update(1);
    }

bool folly::TLRefCount::LocalRefCount::operator-- ( )

inline

Definition at line 164 of file TLRefCount.h.

                      {
      return update(-1);
    }

bool folly::TLRefCount::LocalRefCount::update ( Int  delta )

inlineprivate

Definition at line 169 of file TLRefCount.h.

References folly::asymmetricLightBarrier(), folly::TLRefCount::collectGuard_, count, folly::TLRefCount::LOCAL, and UNLIKELY.

                           {
      if (UNLIKELY(refCount_.state_.load() != State::LOCAL)) {
        return false;
      }

      // This is equivalent to atomic fetch_add. We know that this operation
      // is always performed from a single thread. asymmetricLightBarrier()
      // makes things faster than atomic fetch_add on platforms with native
      // support.
      auto count = count_.load(std::memory_order_relaxed) + delta;
      count_.store(count, std::memory_order_relaxed);

      asymmetricLightBarrier();

      if (UNLIKELY(refCount_.state_.load() != State::LOCAL)) {
        std::lock_guard<std::mutex> lg(collectMutex_);

        if (collectGuard_) {
          return true;
        }
        if (collectCount_ != count) {
          return false;
        }
      }

      return true;
    }

Member Data Documentation

Int folly::TLRefCount::LocalRefCount::collectCount_ {0}

private

Definition at line 201 of file TLRefCount.h.

std::shared_ptr<void> folly::TLRefCount::LocalRefCount::collectGuard_

private

Definition at line 202 of file TLRefCount.h.

std::mutex folly::TLRefCount::LocalRefCount::collectMutex_

private

Definition at line 200 of file TLRefCount.h.

AtomicInt folly::TLRefCount::LocalRefCount::count_ {0}

private

Definition at line 197 of file TLRefCount.h.

TLRefCount& folly::TLRefCount::LocalRefCount::refCount_

private

Definition at line 198 of file TLRefCount.h.

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

• proxygen/folly/folly/experimental/TLRefCount.h