1 /*
<lambda>null2 * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
3 */
4
5 package kotlinx.coroutines.rx2
6
7 import io.reactivex.*
8 import kotlinx.coroutines.*
9 import kotlin.coroutines.*
10
11 /**
12 * Creates cold [single][Single] that will run a given [block] in a coroutine and emits its result.
13 * Every time the returned observable is subscribed, it starts a new coroutine.
14 * Unsubscribing cancels running coroutine.
15 * Coroutine context can be specified with [context] argument.
16 * If the context does not have any dispatcher nor any other [ContinuationInterceptor], then [Dispatchers.Default] is used.
17 * Method throws [IllegalArgumentException] if provided [context] contains a [Job] instance.
18 */
19 public fun <T : Any> rxSingle(
20 context: CoroutineContext = EmptyCoroutineContext,
21 block: suspend CoroutineScope.() -> T
22 ): Single<T> {
23 require(context[Job] === null) { "Single context cannot contain job in it." +
24 "Its lifecycle should be managed via Disposable handle. Had $context" }
25 return rxSingleInternal(GlobalScope, context, block)
26 }
27
rxSingleInternalnull28 private fun <T : Any> rxSingleInternal(
29 scope: CoroutineScope, // support for legacy rxSingle in scope
30 context: CoroutineContext,
31 block: suspend CoroutineScope.() -> T
32 ): Single<T> = Single.create { subscriber ->
33 val newContext = scope.newCoroutineContext(context)
34 val coroutine = RxSingleCoroutine(newContext, subscriber)
35 subscriber.setCancellable(RxCancellable(coroutine))
36 coroutine.start(CoroutineStart.DEFAULT, coroutine, block)
37 }
38
39 private class RxSingleCoroutine<T: Any>(
40 parentContext: CoroutineContext,
41 private val subscriber: SingleEmitter<T>
42 ) : AbstractCoroutine<T>(parentContext, false, true) {
onCompletednull43 override fun onCompleted(value: T) {
44 try {
45 subscriber.onSuccess(value)
46 } catch (e: Throwable) {
47 handleUndeliverableException(e, context)
48 }
49 }
50
onCancellednull51 override fun onCancelled(cause: Throwable, handled: Boolean) {
52 try {
53 if (subscriber.tryOnError(cause)) {
54 return
55 }
56 } catch (e: Throwable) {
57 cause.addSuppressed(e)
58 }
59 handleUndeliverableException(cause, context)
60 }
61 }
62
63 /** @suppress */
64 @Deprecated(
65 message = "CoroutineScope.rxSingle is deprecated in favour of top-level rxSingle",
66 level = DeprecationLevel.HIDDEN,
67 replaceWith = ReplaceWith("rxSingle(context, block)")
68 ) // Since 1.3.0, will be error in 1.3.1 and hidden in 1.4.0
rxSinglenull69 public fun <T : Any> CoroutineScope.rxSingle(
70 context: CoroutineContext = EmptyCoroutineContext,
71 block: suspend CoroutineScope.() -> T
72 ): Single<T> = rxSingleInternal(this, context, block)
73