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1a1f79c0de
Introduce checking of ConcurrentValue conformances: - For structs, check that each stored property conforms to ConcurrentValue - For enums, check that each associated value conforms to ConcurrentValue - For classes, check that each stored property is immutable and conforms to ConcurrentValue Because all of the stored properties / associated values need to be visible for this check to work, limit ConcurrentValue conformances to be in the same source file as the type definition. This checking can be disabled by conforming to a new marker protocol, UnsafeConcurrentValue, that refines ConcurrentValue. UnsafeConcurrentValue otherwise his no specific meaning. This allows both "I know what I'm doing" for types that manage concurrent access themselves as well as enabling retroactive conformance, both of which are fundamentally unsafe but also quite necessary. The bulk of this change ended up being to the standard library, because all conformances of standard library types to the ConcurrentValue protocol needed to be sunk down into the standard library so they would benefit from the checking above. There were numerous little mistakes in the initial pass through the stsandard library types that have now been corrected.
64 lines
1.9 KiB
Swift
64 lines
1.9 KiB
Swift
//===--- UnicodeParser.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) 2014 - 2017 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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extension Unicode {
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/// The result of attempting to parse a `T` from some input.
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@frozen
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public enum ParseResult<T> {
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/// A `T` was parsed successfully
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case valid(T)
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/// The input was entirely consumed.
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case emptyInput
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/// An encoding error was detected.
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///
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/// `length` is the number of underlying code units consumed by this
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/// error, guaranteed to be greater than 0.
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case error(length: Int)
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@inlinable
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internal var _valid: T? {
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if case .valid(let result) = self { return result }
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return nil
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}
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@inlinable
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internal var _error: Int? {
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if case .error(let result) = self { return result }
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return nil
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}
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}
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}
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/// Types that separate streams of code units into encoded Unicode
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/// scalar values.
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public protocol _UnicodeParser {
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/// The encoding with which this parser is associated
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associatedtype Encoding: _UnicodeEncoding
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/// Constructs an instance that can be used to begin parsing `CodeUnit`s at
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/// any Unicode scalar boundary.
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init()
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/// Parses a single Unicode scalar value from `input`.
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mutating func parseScalar<I: IteratorProtocol>(
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from input: inout I
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) -> Unicode.ParseResult<Encoding.EncodedScalar>
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where I.Element == Encoding.CodeUnit
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}
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extension Unicode {
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public typealias Parser = _UnicodeParser
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}
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extension Unicode.ParseResult: ConcurrentValue where T: ConcurrentValue { }
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