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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import Swift
/// A clock that measures time that always increments but stops incrementing
/// while the system is asleep.
///
/// `SuspendingClock` can be considered as a system awake time clock. The frame
/// of reference of the `Instant` may be bound machine boot or some other
/// locally defined reference point. This means that the instants are
/// only comparable on the same machine in the same booted session.
///
/// This clock is suitable for high resolution measurements of execution.
@available(SwiftStdlib 5.7, *)
public struct SuspendingClock: Sendable {
public struct Instant: Codable, Sendable {
internal var _value: Swift.Duration
internal init(_value: Swift.Duration) {
self._value = _value
}
}
public init() { }
}
@available(SwiftStdlib 5.7, *)
extension Clock where Self == SuspendingClock {
/// A clock that measures time that always increments but stops incrementing
/// while the system is asleep.
///
/// try await Task.sleep(until: .now + .seconds(3), clock: .suspending)
///
@available(SwiftStdlib 5.7, *)
public static var suspending: SuspendingClock { return SuspendingClock() }
}
@available(SwiftStdlib 5.7, *)
extension SuspendingClock: Clock {
/// The current instant accounting for machine suspension.
@available(SwiftStdlib 5.7, *)
public var now: SuspendingClock.Instant {
SuspendingClock.now
}
/// The current instant accounting for machine suspension.
@available(SwiftStdlib 5.7, *)
public static var now: SuspendingClock.Instant {
var seconds = Int64(0)
var nanoseconds = Int64(0)
_getTime(
seconds: &seconds,
nanoseconds: &nanoseconds,
clock: _ClockID.suspending.rawValue)
return Instant(
_value: Duration(_seconds: seconds, nanoseconds: nanoseconds)
)
}
/// The minimum non-zero resolution between any two calls to `now`.
@available(SwiftStdlib 5.7, *)
public var minimumResolution: Swift.Duration {
var seconds = Int64(0)
var nanoseconds = Int64(0)
_getClockRes(
seconds: &seconds,
nanoseconds: &nanoseconds,
clock: _ClockID.suspending.rawValue)
return Duration(_seconds: seconds, nanoseconds: nanoseconds)
}
#if !SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
/// Suspend task execution until a given deadline within a tolerance.
/// If no tolerance is specified then the system may adjust the deadline
/// to coalesce CPU wake-ups to more efficiently process the wake-ups in
/// a more power efficient manner.
///
/// If the task is canceled before the time ends, this function throws
/// `CancellationError`.
///
/// This function doesn't block the underlying thread.
@available(SwiftStdlib 5.7, *)
public func sleep(
until deadline: Instant, tolerance: Swift.Duration? = nil
) async throws {
let (seconds, attoseconds) = deadline._value.components
let nanoseconds = attoseconds / 1_000_000_000
try await Task._sleep(until:seconds, nanoseconds,
tolerance: tolerance,
clock: .suspending)
}
#else
@available(SwiftStdlib 5.7, *)
@available(*, unavailable, message: "Unavailable in task-to-thread concurrency model")
public func sleep(
until deadline: Instant, tolerance: Swift.Duration? = nil
) async throws {
fatalError("Unavailable in task-to-thread concurrency model")
}
#endif
}
@available(SwiftStdlib 5.7, *)
extension SuspendingClock.Instant: InstantProtocol {
@available(SwiftStdlib 5.7, *)
public static var now: SuspendingClock.Instant { SuspendingClock().now }
@available(SwiftStdlib 5.7, *)
public func advanced(by duration: Swift.Duration) -> SuspendingClock.Instant {
SuspendingClock.Instant(_value: _value + duration)
}
@available(SwiftStdlib 5.7, *)
public func duration(to other: SuspendingClock.Instant) -> Swift.Duration {
other._value - _value
}
@available(SwiftStdlib 5.7, *)
public func hash(into hasher: inout Hasher) {
hasher.combine(_value)
}
@available(SwiftStdlib 5.7, *)
public static func == (
_ lhs: SuspendingClock.Instant, _ rhs: SuspendingClock.Instant
) -> Bool {
return lhs._value == rhs._value
}
@available(SwiftStdlib 5.7, *)
public static func < (
_ lhs: SuspendingClock.Instant, _ rhs: SuspendingClock.Instant
) -> Bool {
return lhs._value < rhs._value
}
@available(SwiftStdlib 5.7, *)
public static func + (
_ lhs: SuspendingClock.Instant, _ rhs: Swift.Duration
) -> SuspendingClock.Instant {
lhs.advanced(by: rhs)
}
@available(SwiftStdlib 5.7, *)
public static func += (
_ lhs: inout SuspendingClock.Instant, _ rhs: Swift.Duration
) {
lhs = lhs.advanced(by: rhs)
}
@available(SwiftStdlib 5.7, *)
public static func - (
_ lhs: SuspendingClock.Instant, _ rhs: Swift.Duration
) -> SuspendingClock.Instant {
lhs.advanced(by: .zero - rhs)
}
@available(SwiftStdlib 5.7, *)
public static func -= (
_ lhs: inout SuspendingClock.Instant, _ rhs: Swift.Duration
) {
lhs = lhs.advanced(by: .zero - rhs)
}
@available(SwiftStdlib 5.7, *)
public static func - (
_ lhs: SuspendingClock.Instant, _ rhs: SuspendingClock.Instant
) -> Swift.Duration {
rhs.duration(to: lhs)
}
}
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