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6caaa77efc
This adds a setter to the `CxxDictionary` subscript which makes it possible to mutate `std::map` and `std::unordered_map` from Swift. rdar://105399019
76 lines
2.5 KiB
Swift
76 lines
2.5 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) 2014 - 2023 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 C++ type that represents a dictionary.
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///
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/// C++ standard library types such as `std::map` and `std::unordered_map`
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/// conform to this protocol.
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public protocol CxxDictionary<Key, Value> {
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associatedtype Key
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associatedtype Value
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associatedtype Element: CxxPair<Key, Value>
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associatedtype RawIterator: UnsafeCxxInputIterator
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where RawIterator.Pointee == Element
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associatedtype RawMutableIterator: UnsafeCxxMutableInputIterator
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where RawMutableIterator.Pointee == Element
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associatedtype Size: BinaryInteger
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associatedtype InsertionResult
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/// Do not implement this function manually in Swift.
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func __findUnsafe(_ key: Key) -> RawIterator
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/// Do not implement this function manually in Swift.
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mutating func __findMutatingUnsafe(_ key: Key) -> RawMutableIterator
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/// Do not implement this function manually in Swift.
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@discardableResult
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mutating func __insertUnsafe(_ element: Element) -> InsertionResult
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/// Do not implement this function manually in Swift.
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@discardableResult
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mutating func erase(_ key: Key) -> Size
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/// Do not implement this function manually in Swift.
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func __endUnsafe() -> RawIterator
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/// Do not implement this function manually in Swift.
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mutating func __endMutatingUnsafe() -> RawMutableIterator
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}
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extension CxxDictionary {
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@inlinable
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public subscript(key: Key) -> Value? {
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get {
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let iter = __findUnsafe(key)
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guard iter != __endUnsafe() else {
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return nil
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}
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return iter.pointee.second
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}
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set(newValue) {
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guard let newValue = newValue else {
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self.erase(key)
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return
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}
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var iter = self.__findMutatingUnsafe(key)
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if iter != self.__endMutatingUnsafe() {
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// This key already exists in the dictionary.
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iter.pointee.second = newValue
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} else {
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// Create a std::pair<key_type, mapped_type>.
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let keyValuePair = Element(first: key, second: newValue)
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self.__insertUnsafe(keyValuePair)
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}
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}
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}
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}
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