syncmod

Documentation

Overview

Package syncmod contains a clone of package sync's map.go file with unused methods removed and some tweaks with LoadOrStore.

Index

• type Map
  • func (m *Map) Load(key interface{}) (value interface{}, ok bool)
  • func (m *Map) LoadOrStore(k interface{}) (actual interface{}, loaded bool)

Types

type Map

type Map struct {
	New func() interface{}
	// contains filtered or unexported fields
}

Map 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 Map 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 Map 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 Map may significantly reduce lock contention compared to a Go map paired with a separate Mutex or RWMutex.

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

func (*Map) Load

func (m *Map) Load(key interface{}) (value interface{}, 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 (*Map) LoadOrStore

func (m *Map) LoadOrStore(k interface{}) (actual interface{}, 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.