49 lines
1008 B
Go
49 lines
1008 B
Go
package singleton
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import (
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"reflect"
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"strings"
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"github.com/navidrome/navidrome/log"
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)
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var (
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instances = make(map[string]interface{})
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getOrCreateC = make(chan *entry, 1)
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)
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type entry struct {
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constructor func() interface{}
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object interface{}
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resultC chan interface{}
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}
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// Get returns an existing instance of object. If it is not yet created, calls `constructor`, stores the
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// result for future calls and return it
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func Get(object interface{}, constructor func() interface{}) interface{} {
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e := &entry{
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constructor: constructor,
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object: object,
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resultC: make(chan interface{}),
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}
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getOrCreateC <- e
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return <-e.resultC
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}
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func init() {
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go func() {
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for {
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e := <-getOrCreateC
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name := reflect.TypeOf(e.object).String()
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name = strings.TrimPrefix(name, "*")
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v, created := instances[name]
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if !created {
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v = e.constructor()
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log.Trace("Created new singleton", "object", name, "instance", v)
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instances[name] = v
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}
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e.resultC <- v
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}
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}()
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}
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