58 lines
1.2 KiB
Kotlin
58 lines
1.2 KiB
Kotlin
package exh.util
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import kotlinx.coroutines.sync.Mutex
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import kotlinx.coroutines.sync.withLock
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/**
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* Field that can be initialized later. Users can suspend while waiting for the field to initialize.
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*
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* @author nulldev
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*/
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class DeferredField<T> {
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@Volatile
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var content: T? = null
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@Volatile
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var initialized = false
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private set
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private val mutex = Mutex(true)
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/**
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* Initialize the field
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*/
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fun initialize(content: T) {
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// Fast-path new listeners
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this.content = content
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initialized = true
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// Notify current listeners
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mutex.unlock()
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}
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fun set(content: T) {
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mutex.tryLock()
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this.content = content
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initialized = true
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// Notify current listeners
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mutex.unlock()
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}
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/**
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* Will only suspend if !initialized.
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*/
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suspend fun get(): T {
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// Check if field is initialized and return immediately if it is
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@Suppress("UNCHECKED_CAST")
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if (initialized) return content as T
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// Wait for field to initialize
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mutex.withLock {}
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// Field is initialized, return value
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@Suppress("UNCHECKED_CAST")
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return content as T
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}
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}
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