go/src/internal/singleflight/singleflight.go

type call …

type Group …

type Result …

// Do executes and returns the results of the given function, making
// sure that only one execution is in-flight for a given key at a
// time. If a duplicate comes in, the duplicate caller waits for the
// original to complete and receives the same results.
// The return value shared indicates whether v was given to multiple callers.
func (g *Group) Do(key string, fn func() (any, error)) (v any, err error, shared bool) { … }

// DoChan is like Do but returns a channel that will receive the
// results when they are ready.
func (g *Group) DoChan(key string, fn func() (any, error)) <-chan Result { … }

// doCall handles the single call for a key.
func (g *Group) doCall(c *call, key string, fn func() (any, error)) { … }

// ForgetUnshared tells the singleflight to forget about a key if it is not
// shared with any other goroutines. Future calls to Do for a forgotten key
// will call the function rather than waiting for an earlier call to complete.
// Returns whether the key was forgotten or unknown--that is, whether no
// other goroutines are waiting for the result.
func (g *Group) ForgetUnshared(key string) bool { … }