mirror of
https://github.com/apple/swift.git
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Guillaume Lessard
73 lines
2.4 KiB
Swift
73 lines
2.4 KiB
Swift
//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2026 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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/// A safe reference allowing in-place reads to a shared value.
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@available(SwiftStdlib 6.4, *)
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@frozen
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public struct Ref<Value: ~Copyable & ~Escapable>: Copyable, ~Escapable {
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@usableFromInline
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let builtin: Builtin.Borrow<Value>
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/// Initializes an instance of `Ref` with the given borrowed value. This
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/// creates a constant reference to that value preventing writes on the
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/// original value while this reference is still active.
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@available(SwiftStdlib 6.4, *)
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@_alwaysEmitIntoClient
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@_lifetime(borrow value)
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@_transparent
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public init(_ value: borrowing Value) {
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builtin = Builtin.makeBorrow(value)
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}
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/// Unsafely initializes an instance of `Ref` using the given
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/// 'unsafeAddress' as the reference based on the borrowed lifetime of the
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/// given 'owner' argument.
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///
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/// - Parameter unsafeAddress: The address to use to reference an instance of
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/// type `Value`.
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/// - Parameter owner: The owning instance that this `Ref` instance's
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/// lifetime is based on.
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@available(SwiftStdlib 6.4, *)
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@unsafe
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@_alwaysEmitIntoClient
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@_lifetime(borrow owner)
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@_transparent
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public init<Owner: ~Copyable & ~Escapable>(
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unsafeAddress pointer: UnsafePointer<Value>,
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borrowing owner: borrowing Owner
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) {
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builtin = unsafe Builtin.makeBorrow(pointer.pointee)
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}
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}
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@available(SwiftStdlib 6.4, *)
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extension Ref: @unchecked Sendable
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where Value: Sendable & ~Copyable & ~Escapable {}
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@available(SwiftStdlib 6.4, *)
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extension Ref: BitwiseCopyable {}
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@available(SwiftStdlib 6.4, *)
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extension Ref where Value: ~Copyable & ~Escapable {
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/// Dereferences the constant reference allowing for in-place reads to the
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/// underlying value.
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@available(SwiftStdlib 6.4, *)
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@_alwaysEmitIntoClient
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@_transparent
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public var value: Value {
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@_lifetime(copy self)
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borrow {
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Builtin.dereferenceBorrow(builtin)
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}
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}
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}
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