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//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2021 Apple Inc. and the SwiftNIO project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//
import XCTest
@testable import NIO
import NIOConcurrencyHelpers
import Dispatch
final class SALEventLoopTests: XCTestCase, SALTest {
var group: MultiThreadedEventLoopGroup!
var kernelToUserBox: LockedBox<KernelToUser>!
var userToKernelBox: LockedBox<UserToKernel>!
var wakeups: LockedBox<()>!
override func setUp() {
self.setUpSAL()
}
override func tearDown() {
self.tearDownSAL()
}
func testSchedulingTaskOnSleepingLoopWakesUpOnce() throws {
let thisLoop = self.group.next()
try thisLoop.runSAL(syscallAssertions: {
try self.assertParkedRightNow()
try self.assertWakeup()
// We actually need to wait for the inner code to exit, as the optimisation we're testing here will remove a signal that the
// SAL is actually going to wait for in salWait().
try self.assertParkedRightNow()
}) { () -> EventLoopFuture<Void> in
// We're going to execute some tasks on the loop. This will force a single wakeup, as the first task will wedge the loop open.
// However, we're currently _on_ the loop so the first thing we have to do is give it up.
let promise = thisLoop.makePromise(of: Void.self)
DispatchQueue(label: "background").asyncAfter(deadline: .now() + .milliseconds(100)) {
let semaphore = DispatchSemaphore(value: 0)
thisLoop.execute {
// Wedge the loop open. This will also _wake_ the loop.
XCTAssertEqual(semaphore.wait(timeout: .now() + .milliseconds(500)), .success)
print("Unblocking wedged task")
}
// Now execute 10 tasks.
var i = 0
for _ in 0..<10 {
thisLoop.execute {
i &+= 1
}
}
// Now enqueue a "last" task.
let lastTask = thisLoop.submit { i &+= 1 }
// Now we can unblock the semaphore.
semaphore.signal()
lastTask.cascade(to: promise)
}
return promise.futureResult
}.salWait()
}
}
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