Benoit Marty
9 months ago
12 changed files with 246 additions and 131 deletions
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/* |
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* Copyright (c) 2023 New Vector Ltd |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package io.element.android.libraries.architecture |
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import androidx.compose.runtime.MutableState |
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import androidx.compose.runtime.Stable |
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import kotlin.contracts.ExperimentalContracts |
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import kotlin.contracts.InvocationKind |
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import kotlin.contracts.contract |
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/** |
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* Sealed type that allows to model an asynchronous operation triggered by the user. |
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*/ |
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@Stable |
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sealed interface AsyncAction<out T> { |
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/** |
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* Represents an uninitialized operation (i.e. yet to be run by the user). |
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*/ |
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data object Uninitialized : AsyncAction<Nothing> |
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/** |
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* Represents an operation that is currently waiting for user confirmation. |
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*/ |
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data object Confirming : AsyncAction<Nothing> |
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/** |
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* Represents an operation that is currently ongoing. |
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*/ |
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data object Loading : AsyncAction<Nothing> |
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/** |
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* Represents a failed operation. |
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* |
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* @property error the error that caused the operation to fail. |
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*/ |
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data class Failure( |
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val error: Throwable, |
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) : AsyncAction<Nothing> |
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/** |
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* Represents a successful operation. |
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* |
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* @param T the type of data returned by the operation. |
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* @property data the data returned by the operation. |
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*/ |
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data class Success<out T>( |
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val data: T, |
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) : AsyncAction<T> |
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/** |
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* Returns the data returned by the operation, or null otherwise. |
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*/ |
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fun dataOrNull(): T? = when (this) { |
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is Success -> data |
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else -> null |
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} |
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/** |
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* Returns the error that caused the operation to fail, or null otherwise. |
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*/ |
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fun errorOrNull(): Throwable? = when (this) { |
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is Failure -> error |
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else -> null |
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} |
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fun isUninitialized(): Boolean = this == Uninitialized |
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fun isConfirming(): Boolean = this is Confirming |
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fun isLoading(): Boolean = this is Loading |
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fun isFailure(): Boolean = this is Failure |
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fun isSuccess(): Boolean = this is Success |
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} |
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suspend inline fun <T> MutableState<AsyncAction<T>>.runCatchingUpdatingState( |
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errorTransform: (Throwable) -> Throwable = { it }, |
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block: () -> T, |
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): Result<T> = runUpdatingState( |
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state = this, |
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errorTransform = errorTransform, |
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resultBlock = { |
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runCatching { |
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block() |
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} |
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}, |
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) |
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suspend inline fun <T> (suspend () -> T).runCatchingUpdatingState( |
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state: MutableState<AsyncAction<T>>, |
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errorTransform: (Throwable) -> Throwable = { it }, |
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): Result<T> = runUpdatingState( |
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state = state, |
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errorTransform = errorTransform, |
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resultBlock = { |
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runCatching { |
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this() |
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} |
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}, |
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) |
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suspend inline fun <T> MutableState<AsyncAction<T>>.runUpdatingState( |
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errorTransform: (Throwable) -> Throwable = { it }, |
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resultBlock: () -> Result<T>, |
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): Result<T> = runUpdatingState( |
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state = this, |
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errorTransform = errorTransform, |
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resultBlock = resultBlock, |
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) |
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/** |
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* Calls the specified [Result]-returning function [resultBlock] |
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* encapsulating its progress and return value into an [AsyncAction] while |
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* posting its updates to the MutableState [state]. |
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* |
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* @param T the type of data returned by the operation. |
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* @param state the [MutableState] to post updates to. |
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* @param errorTransform a function to transform the error before posting it. |
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* @param resultBlock a suspending function that returns a [Result]. |
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* @return the [Result] returned by [resultBlock]. |
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*/ |
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@OptIn(ExperimentalContracts::class) |
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@Suppress("REDUNDANT_INLINE_SUSPEND_FUNCTION_TYPE") |
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suspend inline fun <T> runUpdatingState( |
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state: MutableState<AsyncAction<T>>, |
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errorTransform: (Throwable) -> Throwable = { it }, |
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resultBlock: suspend () -> Result<T>, |
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): Result<T> { |
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contract { |
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callsInPlace(resultBlock, InvocationKind.EXACTLY_ONCE) |
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} |
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state.value = AsyncAction.Loading |
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return resultBlock().fold( |
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onSuccess = { |
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state.value = AsyncAction.Success(it) |
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Result.success(it) |
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}, |
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onFailure = { |
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val error = errorTransform(it) |
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state.value = AsyncAction.Failure( |
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error = error, |
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) |
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Result.failure(error) |
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} |
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) |
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} |
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