swift-async-algorithms/Sources/AsyncAlgorithms/AsyncRemoveDuplicatesSequence.swift at main · apple/swift-async-algorithms · GitHub

Name: swift-async-algorithms/Sources/AsyncAlgorithms/AsyncRemoveDuplicatesSequence.swift at main · apple/swift-async-algorithms · GitHub
Rating: 4.9 (2995 reviews)
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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift Async Algorithms open source project
//
// Copyright (c) 2022 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
//
//===----------------------------------------------------------------------===//

@available(AsyncAlgorithms 1.0,*)
extensionAsyncSequencewhere Element:Equatable{
 /// Creates an asynchronous sequence that omits repeated elements.
@available(AsyncAlgorithms 1.0,*)
publicfunc removeDuplicates()->AsyncRemoveDuplicatesSequence<Self>{
AsyncRemoveDuplicatesSequence(self){ lhs, rhs in
 lhs == rhs
}
}
}

@available(AsyncAlgorithms 1.0,*)
extensionAsyncSequence{
 /// Creates an asynchronous sequence that omits repeated elements by testing them with a predicate.
@available(AsyncAlgorithms 1.0,*)
publicfunc removeDuplicates(
 by predicate:@escaping@Sendable(Element, Element)async->Bool
)->AsyncRemoveDuplicatesSequence<Self>{
returnAsyncRemoveDuplicatesSequence(self, predicate: predicate)
}

 /// Creates an asynchronous sequence that omits repeated elements by testing them with an error-throwing predicate.
@available(AsyncAlgorithms 1.0,*)
publicfunc removeDuplicates(
 by predicate:@escaping@Sendable(Element, Element)asyncthrows->Bool
)->AsyncThrowingRemoveDuplicatesSequence<Self>{
returnAsyncThrowingRemoveDuplicatesSequence(self, predicate: predicate)
}
}

/// An asynchronous sequence that omits repeated elements by testing them with a predicate.
@available(AsyncAlgorithms 1.0,*)
publicstructAsyncRemoveDuplicatesSequence<Base:AsyncSequence>:AsyncSequence{
publictypealiasElement=Base.Element

 /// The iterator for an `AsyncRemoveDuplicatesSequence` instance.
publicstructIterator:AsyncIteratorProtocol{

@usableFromInline
variterator:Base.AsyncIterator

@usableFromInline
letpredicate:@Sendable(Element, Element)async->Bool

@usableFromInline
varlast:Element?

@usableFromInline
init(iterator:Base.AsyncIterator, predicate:@escaping@Sendable(Element, Element)async->Bool){
self.iterator = iterator
self.predicate = predicate
}

@inlinable
publicmutatingfunc next()asyncrethrows->Element?{
guardlet last = last else{
 last =tryawait iterator.next()
return last
}
whilelet element =tryawait iterator.next(){
ifawait !predicate(last, element){
self.last = element
return element
}
}
 return nil
}
}

@usableFromInline
letbase:Base

@usableFromInline
letpredicate:@Sendable(Element, Element)async->Bool

init(_ base:Base, predicate:@escaping@Sendable(Element, Element)async->Bool){
self.base = base
self.predicate = predicate
}

@inlinable
publicfunc makeAsyncIterator()->Iterator{
Iterator(iterator: base.makeAsyncIterator(), predicate: predicate)
}
}

/// An asynchronous sequence that omits repeated elements by testing them with an error-throwing predicate.
@available(AsyncAlgorithms 1.0,*)
publicstruct AsyncThrowingRemoveDuplicatesSequence<Base:AsyncSequence>:AsyncSequence{
publictypealiasElement=Base.Element

 /// The iterator for an `AsyncThrowingRemoveDuplicatesSequence` instance.
publicstruct Iterator:AsyncIteratorProtocol{

@usableFromInline
variterator:Base.AsyncIterator

@usableFromInline
letpredicate:@Sendable(Element, Element)asyncthrows->Bool

@usableFromInline
varlast:Element?

@usableFromInline
init(iterator:Base.AsyncIterator, predicate:@escaping@Sendable(Element, Element)asyncthrows->Bool){
self.iterator = iterator
self.predicate = predicate
}

@inlinable
publicmutatingfunc next()asyncthrows->Element?{
guardlet last = last else{
 last =tryawait iterator.next()
return last
}
whilelet element =tryawait iterator.next(){
 if tryawait !predicate(last, element){
self.last = element
return element
}
}
returnnil
}
}

 @usableFromInline
letbase:Base

@usableFromInline
letpredicate:@Sendable(Element, Element)asyncthrows->Bool

init(_ base: Base, predicate:@escaping@Sendable(Element, Element)async throws -> Bool){
self.base = base
self.predicate = predicate
}

@inlinable
 public func makeAsyncIterator()->Iterator{
Iterator(iterator: base.makeAsyncIterator(), predicate: predicate)
}
}

@available(AsyncAlgorithms 1.0,*)
extension AsyncRemoveDuplicatesSequence: Sendable where Base: Sendable,Base.Element: Sendable {}
@available(AsyncAlgorithms 1.0,*)
extensionAsyncThrowingRemoveDuplicatesSequence:Sendablewhere Base:Sendable, Base.Element:Sendable{}

@available(*, unavailable)
extensionAsyncRemoveDuplicatesSequence.Iterator:Sendable{}

@available(*, unavailable)
extensionAsyncThrowingRemoveDuplicatesSequence.Iterator:Sendable{}