kotlin.AutoCloseable.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2017 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
@file:Suppress("INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
@file:JvmName("AutoCloseableKt")
@file:kotlin.jvm.JvmPackageName("kotlin.jdk7")
package kotlin
import kotlin.contracts.*
/**
* Executes the given [block] function on this resource and then closes it down correctly whether an exception
* is thrown or not.
*
* In case if the resource is being closed due to an exception occurred in [block], and the closing also fails with an exception,
* the latter is added to the [suppressed][java.lang.Throwable.addSuppressed] exceptions of the former.
*
* @param block a function to process this [AutoCloseable] resource.
* @return the result of [block] function invoked on this resource.
*/
@SinceKotlin("1.2")
@kotlin.internal.InlineOnly
public inline fun T.use(block: (T) -> R): R {
contract {
callsInPlace(block, InvocationKind.EXACTLY_ONCE)
}
var exception: Throwable? = null
try {
return block(this)
} catch (e: Throwable) {
exception = e
throw e
} finally {
this.closeFinally(exception)
}
}
/**
* Closes this [AutoCloseable], suppressing possible exception or error thrown by [AutoCloseable.close] function when
* it's being closed due to some other [cause] exception occurred.
*
* The suppressed exception is added to the list of suppressed exceptions of [cause] exception.
*/
@SinceKotlin("1.2")
@PublishedApi
internal fun AutoCloseable?.closeFinally(cause: Throwable?) = when {
this == null -> {}
cause == null -> close()
else ->
try {
close()
} catch (closeException: Throwable) {
cause.addSuppressed(closeException)
}
}