Repo created

core/outcome/build.gradle.kts

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+plugins {
+    id(ThunderbirdPlugins.Library.kmp)
+}
+
+android {
+    namespace = "net.thunderbird.core.outcome"
+}

core/outcome/src/commonMain/kotlin/net/thunderbird/core/outcome/Outcome.kt

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+package net.thunderbird.core.outcome
+
+sealed interface Outcome<out SUCCESS, out FAILURE> {
+    data class Success<out SUCCESS>(val data: SUCCESS) : Outcome<SUCCESS, Nothing>
+    data class Failure<out FAILURE>(
+        val error: FAILURE,
+        val cause: Any? = null,
+    ) : Outcome<Nothing, FAILURE>
+
+    val isSuccess: Boolean
+        get() = this is Success
+
+    val isFailure: Boolean
+        get() = this is Failure
+
+    companion object {
+        fun <SUCCESS> success(data: SUCCESS): Outcome<SUCCESS, Nothing> = Success(data)
+        fun <FAILURE> failure(error: FAILURE): Outcome<Nothing, FAILURE> = Failure(error)
+    }
+}
+
+/**
+ * Map the value and error of an [Outcome] to a new value.
+ *
+ * @param transformSuccess The function to transform the value of a [Success] to a new value.
+ * @param transformFailure The function to transform the value of a [Failure] to a new value.
+ */
+inline fun <IN_SUCCESS, IN_FAILURE, OUT_SUCCESS, OUT_FAILURE> Outcome<IN_SUCCESS, IN_FAILURE>.map(
+    transformSuccess: (IN_SUCCESS) -> OUT_SUCCESS,
+    transformFailure: (IN_FAILURE, Any?) -> OUT_FAILURE,
+): Outcome<OUT_SUCCESS, OUT_FAILURE> {
+    return when (this) {
+        is Outcome.Success -> Outcome.Success(transformSuccess(data))
+        is Outcome.Failure -> Outcome.Failure(transformFailure(error, cause))
+    }
+}
+
+/**
+ * Map the value of a [Outcome] to a new value.
+ *
+ * @param transformSuccess The function to transform the value of a [Success] to a new value.
+ */
+inline fun <IN_SUCCESS, OUT_SUCCESS, FAILURE> Outcome<IN_SUCCESS, FAILURE>.mapSuccess(
+    transformSuccess: (IN_SUCCESS) -> OUT_SUCCESS,
+): Outcome<OUT_SUCCESS, FAILURE> {
+    return when (this) {
+        is Outcome.Success -> Outcome.Success(transformSuccess(data))
+        is Outcome.Failure -> this
+    }
+}
+
+/**
+ * Flat map the value and error of an [Outcome] to a new [Outcome].
+ */
+inline fun <IN_SUCCESS, FAILURE, OUT_SUCCESS> Outcome<IN_SUCCESS, FAILURE>.flatMapSuccess(
+    transformSuccess: (IN_SUCCESS) -> Outcome<OUT_SUCCESS, FAILURE>,
+): Outcome<OUT_SUCCESS, FAILURE> {
+    return when (this) {
+        is Outcome.Success -> transformSuccess(data)
+        is Outcome.Failure -> this
+    }
+}
+
+/**
+ * Map the error of a [Outcome] to a new value.
+ *
+ * @param transformFailure The function to transform the value of a [Failure] to a new value.
+ */
+inline fun <SUCCESS, IN_FAILURE, OUT_FAILURE> Outcome<SUCCESS, IN_FAILURE>.mapFailure(
+    transformFailure: (IN_FAILURE, Any?) -> OUT_FAILURE,
+): Outcome<SUCCESS, OUT_FAILURE> {
+    return when (this) {
+        is Outcome.Success -> this
+        is Outcome.Failure -> Outcome.Failure(transformFailure(error, cause))
+    }
+}
+
+/**
+ * Handle the value of an [Outcome] and execute the given function.
+ *
+ * @param onSuccess The function to execute if the outcome is a [Success].
+ * @param onFailure The function to execute if the outcome is a [Failure].
+ */
+fun <SUCCESS, FAILURE> Outcome<SUCCESS, FAILURE>.handle(
+    onSuccess: (SUCCESS) -> Unit,
+    onFailure: (FAILURE) -> Unit,
+) {
+    when (this) {
+        is Outcome.Success -> onSuccess(data)
+        is Outcome.Failure -> onFailure(error)
+    }
+}
+
+/**
+ * Handle the value of an [Outcome] and execute the given function.
+ *
+ * @param onSuccess The function to execute if the outcome is a [Success].
+ * @param onFailure The function to execute if the outcome is a [Failure].
+ */
+suspend fun <SUCCESS, FAILURE> Outcome<SUCCESS, FAILURE>.handleAsync(
+    onSuccess: suspend (SUCCESS) -> Unit,
+    onFailure: suspend (FAILURE) -> Unit,
+) {
+    when (this) {
+        is Outcome.Success -> onSuccess(data)
+        is Outcome.Failure -> onFailure(error)
+    }
+}