go.temporal.io/server/common/collection/oncemap.go
84 LOC · 24 covered · 60 uncovered · 4 ranges · 81 concepts · 3 introducers · 19 tests
File neighbourhood
The centred file is linked to every concept that introduces one of its ranges, every test that runs code from the file, and the gray connector concepts standing between those tests and the file's own introducer concepts. Undirected links join concepts to every file where they introduce source and concepts to the tests they introduce; arrows show specialization between the displayed concepts and bridge only concepts omitted from this view. Concept colors match the source ranges below; connector concepts have no source color and are shown in gray.
Focused file, its introducer and connector concepts, their introduced files, and tests that run code from the file
In the embedded map, ordinary wheel input scrolls the page; use the visible controls to zoom and drag to pan. Open the full-screen map for canvas navigation: wheel pans, Ctrl/Command plus wheel zooms, and arrow keys pan when this region is focused. On touch screens, open the full-screen map to pan or pinch. If JavaScript or WebGL is unavailable, use the related-file, concept, and source links on this page.
Graph controls are ready.
Interactive rendering requires JavaScript and WebGL. Use the related-file, concept, and source links on this page while the interactive map is unavailable.
package collection
import "sync"
// OnceMap is a concurrent map which lazily constructs its values. Map values are initialized on-the-fly, using a
// provided construction function only when a key is accessed for the first time.
type OnceMap[K comparable, T any] struct {
mu sync.RWMutex
inner map[K]T
construct func(K) T
}
// NewOnceMap creates a [OnceMap] from a given construct function.
// construct should be kept light as it is called while holding a lock on the entire map.
return &OnceMap[K, T]{
construct: construct,
inner: make(map[K]T, 0),
}
}
m.mu.RLock()
value, ok := m.inner[key]
m.mu.RUnlock()
if !ok {
m.mu.Lock()
defer m.mu.Unlock()
if value, ok = m.inner[key]; !ok {
value = m.construct(key)
m.inner[key] = value
}
}
}
// FallibleOnceMap is a concurrent map which lazily constructs its values. Map values are initialized on-the-fly, using
// a provided construction function only when a key is accessed for the first time.
// If the construct function returns an error, the value is not cached.
type FallibleOnceMap[K comparable, T any] struct {
mu sync.RWMutex
inner map[K]T
construct func(K) (T, error)
}
// NewFallibleOnceMap creates a [FallibleOnceMap] from a given construct function.
// construct should be kept light as it is called while holding a lock on the entire map.
func NewFallibleOnceMap[K comparable, T any](construct func(K) (T, error)) *FallibleOnceMap[K, T] {
frontend_http_client.go ×1
return &FallibleOnceMap[K, T]{
construct: construct,
inner: make(map[K]T, 0),
}
}
func (p *FallibleOnceMap[K, T]) Get(key K) (T, error) {
p.mu.RLock()
value, ok := p.inner[key]
p.mu.RUnlock()
if !ok {
p.mu.Lock()
defer p.mu.Unlock()
if value, ok = p.inner[key]; !ok {
var err error
value, err = p.construct(key)
if err != nil {
return value, err
}
p.inner[key] = value
}
}
return value, nil
}
func (p *FallibleOnceMap[K, T]) Pop(key K) (T, bool) {
p.mu.Lock()
defer p.mu.Unlock()
val, ok := p.inner[key]
if ok {
delete(p.inner, key)
}
return val, ok
}