Published Cell

In this lab, build a small lock-free publication primitive using atomic.Pointer.

Function signatures

type PublishedCell struct { ... }

func NewPublishedCell() *PublishedCell
func (c *PublishedCell) Store(value int)
func (c *PublishedCell) Load() (value int, ok bool)
func (c *PublishedCell) Swap(value int) (previous int, ok bool)

Contract

• Store publishes a new immutable snapshot.
• Load returns (0, false) when no value has been published yet.
• Swap returns the previous published value and true when one exists; returns (0, false) if empty.
• The API must be safe for concurrent readers and writers.
• Readers must never observe a partially initialized state.
• Avoid additional synchronization where atomics are sufficient.

Notes

• Use sync/atomic pointer APIs.
• Keep behavior deterministic for nil receiver calls.
• Do not panic on empty cells.

Complexity

• Store, Load, Swap: O(1).