org.jetbrains.kotlin.gradle.utils.Delegates.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
package org.jetbrains.kotlin.gradle.utils
import kotlin.reflect.KProperty
open class ProviderDelegate(
private val defaultValueProvider: () -> T
) {
operator fun getValue(thisRef: Any?, property: KProperty<*>): T {
return defaultValueProvider()
}
}
class PropertyDelegate(
private val defaultValueProvider: () -> T
) {
private var backing: T? = null
operator fun getValue(thisRef: Any?, property: KProperty<*>): T {
return backing ?: defaultValueProvider()
}
operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
backing = value
}
}
fun provider(
defaultValueProvider: () -> T
): ProviderDelegate = ProviderDelegate(defaultValueProvider)
fun property(
defaultValueProvider: () -> T
): PropertyDelegate = PropertyDelegate(defaultValueProvider)
/**
* Similar to [SynchronizedLazyImpl] but doesn't implement [Serializable] in the way
* that value gets initialised upon serialisation.
* It is intended that [initializer] gets serialised.
* Reason: Sometimes Gradle Configuration Cache can't serialise some entities that
* are produced by [initializer] but is okay serialising [initializer]
*/
internal class TransientLazy(
private val initializer: () -> T
) : Lazy {
@Volatile
@Transient
private var _value: T? = null
override fun isInitialized(): Boolean = _value != null
override val value get(): T {
val v1 = _value
if (v1 != null) return v1
return synchronized(this) {
val v2 = _value
if (v2 == null) {
initializer().also { _value = it }
} else {
v2
}
}
}
}