commonMain.ua.railian.data.result.DataResult-base.kt Maven / Gradle / Ivy

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DataResult is a discriminated union that encapsulates a successful outcome with a value of type [T] or a failure with an error of type [E].

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@file:OptIn(ExperimentalContracts::class)

package ua.railian.data.result

import ua.railian.data.result.DataResult.Factory
import ua.railian.data.result.DataResult.Success
import kotlin.contracts.ExperimentalContracts
import kotlin.contracts.InvocationKind
import kotlin.contracts.contract

//region Factory
/**
 * Builds a new [DataResult] by populating a [Factory] using the given [builder].
 */
public inline fun  Factory.build(
    builder: Factory.() -> DataResult,
): DataResult = builder()
//endregion

//region Transformations
/**
 * Returns the encapsulated result of the given [transform] function
 * applied to the encapsulated value if this instance represents [success][isSuccess]
 * or the original encapsulated error if it is [failure][isFailure].
 *
 * Note, that this function rethrows any [Throwable] exception thrown by [transform] function.
 */
public inline fun  DataResult.map(
    transform: (value: T) -> R,
): DataResult = flatMap { success(transform(it)) }

/**
 * Returns the result of the given [transform] function
 * applied to the encapsulated value if this instance represents [success][isSuccess]
 * or the original result if it is [failure][isFailure].
 *
 * Note, that this function rethrows any [Throwable] exception thrown by [transform] function.
 */
public inline fun  DataResult.flatMap(
    transform: Factory.(value: T) -> DataResult,
): DataResult {
    contract { callsInPlace(transform, InvocationKind.AT_MOST_ONCE) }
    @Suppress("UNCHECKED_CAST")
    return when {
        isFailure() -> this as DataResult
        else -> DataResult.transform(value)
    }
}

/**
 * Returns the encapsulated result of the given [transform] function
 * applied to the encapsulated error if this instance represents [failure][isFailure]
 * or the original encapsulated value if it is [success][isSuccess].
 *
 * Note, that this function rethrows any [Throwable] exception thrown by [transform] function.
 */
public inline fun  DataResult.recover(
    transform: (error: E) -> R,
): Success = flatRecover { success(transform(it)) } as Success

/**
 * Returns the result of the given [transform] function
 * applied to the encapsulated error if this instance represents [failure][isFailure]
 * or the original result if it is [success][isSuccess].
 *
 * Note, that this function rethrows any [Throwable] exception thrown by [transform] function.
 */
public inline fun  DataResult.flatRecover(
    transform: Factory.(error: E) -> DataResult,
): DataResult {
    contract { callsInPlace(transform, InvocationKind.AT_MOST_ONCE) }
    @Suppress("UNCHECKED_CAST")
    return when {
        isSuccess() -> this as DataResult
        else -> DataResult.transform(error)
    }
}

/**
 * Returns the result of the given [transform] function applied to the original result.
 *
 * Note, that this function rethrows any [Throwable] exception thrown by [transform] function.
 */
public inline fun  DataResult.transform(
    transform: Factory.(result: DataResult) -> DataResult,
): DataResult {
    contract { callsInPlace(transform, InvocationKind.EXACTLY_ONCE) }
    return DataResult.transform(this)
}
//endregion