Generalize ContiguousBytes to be noncopyable and nonescapable for spans #1565
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The ContiguousBytes protocol covers various types that can provide unsafe access to their stored bytes. Generalize the ContiguousBytes protocol by making it non-copyable and non-escapable, so that the Span family of types and InlineArray can conform to it. Fixes rdar://163716671.
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@swift-ci please test |
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| //===--- ContiguousBytes --------------------------------------------------===// | ||
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| #if compiler(>=6.2) |
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Foundation only compiles with the most recent released compiler + main, so I don't think this check is required.
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| //===--- Span Conformances -----------------------------------------===// | ||
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| @available(FoundationPreview 6.3, *) |
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This is a public conformance, right? We would need an API review.
| acceptContiguousBytes(bytes.span.bytes) | ||
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| let ms = bytes.mutableSpan | ||
| acceptContiguousBytes(ms.bytes) |
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| acceptContiguousBytes(ms.bytes) | |
| acceptContiguousBytes(ms.mutableBytes) |
| /// Indicates that the conforming type is a contiguous collection of raw bytes | ||
| /// whose underlying storage is directly accessible by withUnsafeBytes. | ||
| @available(macOS 10.10, iOS 8.0, watchOS 2.0, tvOS 9.0, *) | ||
| public protocol ContiguousBytes: ~Escapable, ~Copyable { |
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Just confirming, are there any ABI implications on this change?
| } | ||
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| @available(FoundationPreview 6.3, *) | ||
| @available(macOS 26.0, iOS 26.0, tvOS 26.0, watchOS 26.0, visionOS 26.0, *) |
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The double availability attribute seems a bit suspicious here - each declaration should only have a single availability. Is the problem here the macOS back deployment build of the package? If so, we'll need to create a new availability macro (something like FoundationInlineArray) that maps to macOS 26-aligned in the package manifest / CMake files
| private struct ContiguousBytesTests { | ||
| @available(macOS 26.0, iOS 26.0, tvOS 26.0, watchOS 26.0, visionOS 26.0, *) | ||
| @Test func span() throws { | ||
| if #available(FoundationPreview 6.3, *) { |
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Since the function is already annotated as only available on macOS 26+, I don't think we need this #available check here. In the end what we probably want is for this function to be annotated as @available(FoundationInlineArray 6.3, *)
| /// the same buffer pointer will be passed in every time. | ||
| /// - warning: The buffer argument to the body should not be stored or used | ||
| /// outside of the lifetime of the call to the closure. | ||
| func withUnsafeBytes<R>(_ body: (UnsafeRawBufferPointer) throws -> R) rethrows -> R |
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There's probably still work to be done on this protocol to update it (it doesn't allow for producing a span, it hasn't adopted typed throws, etc.) but this seems like a reasonable step in a good direction that we can do without fully fleshing out those changes at the moment if we want to update this incrementally
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The ContiguousBytes protocol covers various types that can provide unsafe access to their stored bytes. Generalize the ContiguousBytes protocol by making it non-copyable and non-escapable, so that the Span family of types and InlineArray can conform to it.
Fixes rdar://163716671.