Mihaela Mihaljevic
36b2a73637
The rules-swift concurrency rule's acceptance check requires every `@unchecked Sendable` and `nonisolated(unsafe)` to carry an adjacent comment explaining why the race is acceptable; an unjustified one is a violation. An audit found six escape hatches whose comment explained the type but not the race: - The four XPath `FunctionTable` statics (`CoreFunctions`, `StringFunctions`, `NodeFunctions`, `Evaluator.library`): each is an immutable, build-once lookup table never mutated after initialization, so concurrent reads race on nothing; `FunctionTable` is un-`Sendable` only because it stores closures. - `Validation.Validator`: immutable after `init` (every stored validation list is a `let`); the erased `AnyValidation` closures are simply not provably `Sendable`. - The test `ResultBox`: written once by the worker thread before its semaphore signals and read only after the wait, so the write happens-before the read. Comments only; no behaviour change. `LoaderBox` and `ElementStorage` were already justified. swiftformat/swiftlint --strict and the full suite stay green.
34 lines
1.7 KiB
Swift
34 lines
1.7 KiB
Swift
extension PureXML.XPath {
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/// The core XPath functions tied to the four-type model and predicates:
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/// `last`, `position`, `count`, `not`, `true`, `false`, `boolean`, `number`,
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/// and `string`. The broader library (string, node, and number functions)
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/// extends this table.
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enum CoreFunctions {
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// nonisolated(unsafe): an immutable, build-once table never mutated after
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// initialization, so concurrent reads are safe; `FunctionTable` is only
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// un-`Sendable` because it stores closures.
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nonisolated(unsafe) static let table = FunctionTable([
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"last": { _, context in .number(Double(context.size)) },
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"position": { _, context in .number(Double(context.position)) },
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"count": { arguments, _ in
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guard let nodes = arguments.first?.nodes else {
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throw PureXML.XPath.QueryError.invalidArguments("count() requires a node-set")
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}
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return .number(Double(nodes.count))
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},
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"not": { arguments, _ in .boolean(!(arguments.first?.boolean ?? false)) },
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"true": { _, _ in .boolean(true) },
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"false": { _, _ in .boolean(false) },
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"boolean": { arguments, _ in .boolean(arguments.first?.boolean ?? false) },
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"number": { arguments, context in
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if let first = arguments.first { return .number(first.number) }
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return .number(PureXML.XPath.Value.parseNumber(context.node.stringValue))
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},
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"string": { arguments, context in
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if let first = arguments.first { return .string(first.string) }
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return .string(context.node.stringValue)
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},
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])
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}
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}
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