coroutines.kt

class AsyncFreenetInterfaceTest {

	@Test
	fun `returned deferred is completed by success`() = runBlocking {
		val result = FetchResult(ClientMetadata(), NullBucket())
		val freenetClient = object : FreenetClient {
			override fun fetch(freenetKey: FreenetURI) = result
		}
		val freenetInterface = AsyncFreenetInterface(freenetClient)
		val fetched = async { freenetInterface.fetchUri(FreenetURI("KSK@GPL.txt")) }

		withTimeout(1000) {
			assertThat(fetched.await(), equalTo(Fetched(FreenetURI("KSK@GPL.txt"), result)))
		}
	}

	@Test
	fun `permanent redircts are being followed`() = runBlocking {
		val result = FetchResult(ClientMetadata(), NullBucket())
		val freenetClient = object : FreenetClient {
			val redirected = AtomicBoolean(false)
			override fun fetch(freenetKey: FreenetURI) =
					if (redirected.compareAndSet(false, true))
						throw FetchException(FetchException.FetchExceptionMode.PERMANENT_REDIRECT, FreenetURI("KSK@GPLv3.txt"))
					else result
		}
		val freenetInterface = AsyncFreenetInterface(freenetClient)
		val fetched = async { freenetInterface.fetchUri(FreenetURI("KSK@GPL.txt")) }

		withTimeout(1000) {
			assertThat(fetched.await(), equalTo(Fetched(FreenetURI("KSK@GPLv3.txt"), result)))
		}
	}

	@Test
	fun `fetch errors are being re-thrown`() = runBlocking<Unit> {
		val freenetClient = object : FreenetClient {
			override fun fetch(freenetKey: FreenetURI) =
					throw FetchException(FetchException.FetchExceptionMode.ALL_DATA_NOT_FOUND)
		}
		val freenetInterface = AsyncFreenetInterface(freenetClient)
		println("a")
		val fetched = async { freenetInterface.fetchUri(FreenetURI("KSK@GPL.txt")) }
		println("b")

		withTimeout(1000) {
			assertFailsWith(FetchException::class) {
				println("d")
				println("e: ${fetched.await()}")
				println("c")
			}
		}
	}

}

class AsyncFreenetInterface(private val freenetClient: FreenetClient) {

	suspend fun fetchUri(freenetUri: FreenetURI): Fetched = coroutineScope {
		var currentUri = freenetUri
		var result: FetchResult? = null
		while (result == null) {
			try {
				result = withContext(Dispatchers.Default) { freenetClient.fetch(currentUri) }
			} catch (fetchException: FetchException) {
				if (fetchException.mode == FetchException.FetchExceptionMode.PERMANENT_REDIRECT) {
					currentUri = fetchException.newURI
					continue
				} else
					throw fetchException
			}
		}
		Fetched(currentUri, result)
	}

}