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[Windows] Thread.sleep(...) time interval precision loss #2576

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Merged
merged 1 commit into from
Dec 10, 2019
Merged

[Windows] Thread.sleep(...) time interval precision loss #2576

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4 changes: 2 additions & 2 deletions Foundation/Thread.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -119,7 +119,7 @@ open class Thread : NSObject {

// the timeout is in 100ns units
var liTimeout: LARGE_INTEGER =
LARGE_INTEGER(QuadPart: LONGLONG(date.timeIntervalSinceNow) * -10000000)
LARGE_INTEGER(QuadPart: LONGLONG(date.timeIntervalSinceNow * -10_000_000))
if !SetWaitableTimer(hTimer, &liTimeout, 0, nil, nil, false) {
return
}
Expand Down Expand Up @@ -156,7 +156,7 @@ open class Thread : NSObject {

// the timeout is in 100ns units
var liTimeout: LARGE_INTEGER =
LARGE_INTEGER(QuadPart: LONGLONG(interval) * -10000000)
LARGE_INTEGER(QuadPart: LONGLONG(interval * -10_000_000))
if !SetWaitableTimer(hTimer, &liTimeout, 0, nil, nil, false) {
return
}
Expand Down
44 changes: 44 additions & 0 deletions TestFoundation/TestThread.swift
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Expand Up @@ -27,6 +27,8 @@ class TestThread : XCTestCase {
("test_mainThread", test_mainThread),
("test_callStackSymbols", testExpectedToFailOnAndroid(test_callStackSymbols, "Android doesn't support backtraces at the moment.")),
("test_callStackReturnAddresses", testExpectedToFailOnAndroid(test_callStackReturnAddresses, "Android doesn't support backtraces at the moment.")),
("test_sleepForTimeInterval", test_sleepForTimeInterval),
("test_sleepUntilDate", test_sleepUntilDate),
]

#if NS_FOUNDATION_ALLOWS_TESTABLE_IMPORT
Expand Down Expand Up @@ -151,4 +153,46 @@ class TestThread : XCTestCase {
XCTAssertTrue(addresses.count > 0)
XCTAssertTrue(addresses.count <= 128)
}

func test_sleepForTimeInterval() {
let measureOversleep = { (timeInterval: TimeInterval) -> TimeInterval in
let start = Date()
Thread.sleep(forTimeInterval: timeInterval)

// Measures time Thread.sleep spends over specified timeInterval value
return -(start.timeIntervalSinceNow + timeInterval)
}

// Allow a little early wake-ups. Sleep timer on Windows
// is more precise than timer used in Date implementation.
let allowedOversleepRange = -0.00001..<0.1

let oversleep1 = measureOversleep(TimeInterval(0.9))
XCTAssertTrue(allowedOversleepRange.contains(oversleep1), "Oversleep \(oversleep1) is not in expected range \(allowedOversleepRange)")

let oversleep2 = measureOversleep(TimeInterval(1.2))
XCTAssertTrue(allowedOversleepRange.contains(oversleep2), "Oversleep \(oversleep2) is not in expected range \(allowedOversleepRange)")

let oversleep3 = measureOversleep(TimeInterval(1.0))
XCTAssertTrue(allowedOversleepRange.contains(oversleep3), "Oversleep \(oversleep3) is not in expected range \(allowedOversleepRange)")
}

func test_sleepUntilDate() {
let measureOversleep = { (date: Date) -> TimeInterval in
Thread.sleep(until: date)
return -date.timeIntervalSinceNow
}

let allowedOversleepRange = -0.00001..<0.1

let oversleep1 = measureOversleep(Date(timeIntervalSinceNow: 0.8))
XCTAssertTrue(allowedOversleepRange.contains(oversleep1), "Oversleep \(oversleep1) is not in expected range \(allowedOversleepRange)")

let oversleep2 = measureOversleep(Date(timeIntervalSinceNow: 1.1))
XCTAssertTrue(allowedOversleepRange.contains(oversleep2), "Oversleep \(oversleep2) is not in expected range \(allowedOversleepRange)")

let oversleep3 = measureOversleep(Date(timeIntervalSinceNow: 1.0))
XCTAssertTrue(allowedOversleepRange.contains(oversleep3), "Oversleep \(oversleep3) is not in expected range \(allowedOversleepRange)")
}

}