xref: /external/v8/src/unbound-queue.h

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#ifndef V8_UNBOUND_QUEUE_
#define V8_UNBOUND_QUEUE_

#include "allocation.h"

namespace v8 {
namespace internal {


// Lock-free unbound queue for small records.  Intended for
// transferring small records between a Single producer and a Single
// consumer. Doesn't have restrictions on the number of queued
// elements, so producer never blocks.  Implemented after Herb
// Sutter's article:
// http://www.ddj.com/high-performance-computing/210604448
template<typename Record>
class UnboundQueue BASE_EMBEDDED {
 public:
  inline UnboundQueue();
  inline ~UnboundQueue();

  INLINE(void Dequeue(Record* rec));
  INLINE(void Enqueue(const Record& rec));
  INLINE(bool IsEmpty()) { return divider_ == last_; }
  INLINE(Record* Peek());

 private:
  INLINE(void DeleteFirst());

  struct Node;

  Node* first_;
  AtomicWord divider_;  // Node*
  AtomicWord last_;     // Node*

  DISALLOW_COPY_AND_ASSIGN(UnboundQueue);
};


} }  // namespace v8::internal

#endif  // V8_UNBOUND_QUEUE_