generic_sync

Documentation

Index

• type MapOf
  • func (m *MapOf[K, V]) Clear()
  • func (m *MapOf[K, V]) Delete(key K)
  • func (m *MapOf[K, V]) Load(key K) (value V, ok bool)
  • func (m *MapOf[K, V]) LoadOrStore(key K, value V) (actual V, loaded bool)
  • func (m *MapOf[K, V]) Range(f func(key K, value V) bool)
  • func (m *MapOf[K, V]) Store(key K, value V)
  • func (m *MapOf[K, V]) Values() []V

Types

type MapOf

type MapOf[K comparable, V any] struct {
	// contains filtered or unexported fields
}

MapOf is like a Go map[interface{}]interface{} but is safe for concurrent use by multiple goroutines without additional locking or coordination. Loads, stores, and deletes run in amortized constant time.

The MapOf type is specialized. Most code should use a plain Go map instead, with separate locking or coordination, for better type safety and to make it easier to maintain other invariants along with the map content.

The MapOf type is optimized for two common use cases: (1) when the entry for a given key is only ever written once but read many times, as in caches that only grow, or (2) when multiple goroutines read, write, and overwrite entries for disjoint sets of keys. In these two cases, use of a MapOf may significantly reduce lock contention compared to a Go map paired with a separate Mutex or RWMutex.

The zero MapOf is empty and ready for use. A MapOf must not be copied after first use.

func (*MapOf[K, V]) Clear

func (m *MapOf[K, V]) Clear()

func (*MapOf[K, V]) Delete

func (m *MapOf[K, V]) Delete(key K)

Delete deletes the value for a key.

func (*MapOf[K, V]) Load

func (m *MapOf[K, V]) Load(key K) (value V, ok bool)

Load returns the value stored in the map for a key, or nil if no value is present. The ok result indicates whether value was found in the map.

func (*MapOf[K, V]) LoadOrStore

func (m *MapOf[K, V]) LoadOrStore(key K, value V) (actual V, loaded bool)

LoadOrStore returns the existing value for the key if present. Otherwise, it stores and returns the given value. The loaded result is true if the value was loaded, false if stored.

func (*MapOf[K, V]) Range

func (m *MapOf[K, V]) Range(f func(key K, value V) bool)

Range calls f sequentially for each key and value present in the map. If f returns false, range stops the iteration.

Range does not necessarily correspond to any consistent snapshot of the MapOf's contents: no key will be visited more than once, but if the value for any key is stored or deleted concurrently, Range may reflect any mapping for that key from any point during the Range call.

Range may be O(N) with the number of elements in the map even if f returns false after a constant number of calls.

func (*MapOf[K, V]) Store

func (m *MapOf[K, V]) Store(key K, value V)

Store sets the value for a key.

func (*MapOf[K, V]) Values

func (m *MapOf[K, V]) Values() []V

Values returns a slice of the values in the map.