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iCharlesHuiCharlesHu
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Introduce Swift Subprocess
1 parent 0e23938 commit 93fb0b9

13 files changed

+2637
-1
lines changed

‎Package.swift

+5-1
Original file line numberDiff line numberDiff line change
@@ -33,7 +33,10 @@ let package = Package(
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exact: "0.0.5"),
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.package(
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url: "https://github.com/apple/swift-syntax.git",
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from: "509.0.2")
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from: "509.0.2"),
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.package(
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url: "https://github.com/apple/swift-system",
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from: "1.0.0")
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],
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targets: [
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// Foundation (umbrella)
@@ -63,6 +66,7 @@ let package = Package(
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"_CShims",
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"FoundationMacros",
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.product(name: "_RopeModule", package: "swift-collections"),
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.product(name: "SystemPackage", package: "swift-system"),
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],
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cSettings: [
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.define("_GNU_SOURCE", .when(platforms: [.linux]))

‎Sources/FoundationEssentials/AsyncLineSequence.swift

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@@ -0,0 +1,168 @@
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//===----------------------------------------------------------------------===//
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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) 2019 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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@available(macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0, *)
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public struct AsyncLineSequence<Base: AsyncSequence>: AsyncSequence where Base.Element == UInt8 {
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public typealias Element = String
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var base: Base
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public struct AsyncIterator: AsyncIteratorProtocol {
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public typealias Element = String
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var byteSource: Base.AsyncIterator
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var buffer: Array<UInt8> = []
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var leftover: UInt8? = nil
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internal init(underlyingIterator: Base.AsyncIterator) {
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byteSource = underlyingIterator
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}
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// We'd like to reserve flexibility to improve the implementation of
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// next() in the future, so aren't marking it @inlinable. Manually
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// specializing for the common source types helps us get back some of
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// the performance we're leaving on the table.
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@_specialize(where Base == Subprocess.AsyncBytes)
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public mutating func next() async rethrows -> String? {
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/*
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0D 0A: CR-LF
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0A | 0B | 0C | 0D: LF, VT, FF, CR
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E2 80 A8: U+2028 (LINE SEPARATOR)
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E2 80 A9: U+2029 (PARAGRAPH SEPARATOR)
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*/
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let _CR: UInt8 = 0x0D
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let _LF: UInt8 = 0x0A
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let _NEL_PREFIX: UInt8 = 0xC2
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let _NEL_SUFFIX: UInt8 = 0x85
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let _SEPARATOR_PREFIX: UInt8 = 0xE2
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let _SEPARATOR_CONTINUATION: UInt8 = 0x80
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let _SEPARATOR_SUFFIX_LINE: UInt8 = 0xA8
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let _SEPARATOR_SUFFIX_PARAGRAPH: UInt8 = 0xA9
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func yield() -> String? {
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defer {
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buffer.removeAll(keepingCapacity: true)
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}
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if buffer.isEmpty {
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return nil
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}
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return String(decoding: buffer, as: UTF8.self)
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}
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func nextByte() async throws -> UInt8? {
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defer { leftover = nil }
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if let leftover = leftover {
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return leftover
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}
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return try await byteSource.next()
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}
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while let first = try await nextByte() {
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switch first {
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case _CR:
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let result = yield()
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// Swallow up any subsequent LF
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guard let next = try await byteSource.next() else {
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return result //if we ran out of bytes, the last byte was a CR
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}
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if next != _LF {
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leftover = next
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}
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if let result = result {
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return result
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}
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continue
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case _LF..<_CR:
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guard let result = yield() else {
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continue
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}
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return result
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case _NEL_PREFIX: // this may be used to compose other UTF8 characters
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guard let next = try await byteSource.next() else {
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// technically invalid UTF8 but it should be repaired to "\u{FFFD}"
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buffer.append(first)
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return yield()
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}
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if next != _NEL_SUFFIX {
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buffer.append(first)
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buffer.append(next)
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} else {
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guard let result = yield() else {
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continue
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}
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return result
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}
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case _SEPARATOR_PREFIX:
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// Try to read: 80 [A8 | A9].
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// If we can't, then we put the byte in the buffer for error correction
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guard let next = try await byteSource.next() else {
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buffer.append(first)
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return yield()
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}
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guard next == _SEPARATOR_CONTINUATION else {
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buffer.append(first)
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buffer.append(next)
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continue
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}
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guard let fin = try await byteSource.next() else {
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buffer.append(first)
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buffer.append(next)
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return yield()
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}
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guard fin == _SEPARATOR_SUFFIX_LINE || fin == _SEPARATOR_SUFFIX_PARAGRAPH else {
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buffer.append(first)
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buffer.append(next)
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buffer.append(fin)
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continue
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}
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if let result = yield() {
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return result
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}
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continue
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default:
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buffer.append(first)
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}
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}
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// Don't emit an empty newline when there is no more content (e.g. end of file)
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if !buffer.isEmpty {
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return yield()
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}
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return nil
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}
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}
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public func makeAsyncIterator() -> AsyncIterator {
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return AsyncIterator(underlyingIterator: base.makeAsyncIterator())
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}
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internal init(underlyingSequence: Base) {
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base = underlyingSequence
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}
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}
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@available(macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0, *)
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extension AsyncLineSequence : Sendable where Base : Sendable {}
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@available(macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0, *)
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extension AsyncLineSequence.AsyncIterator : Sendable where Base.AsyncIterator : Sendable {}
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@available(macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0, *)
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public extension AsyncSequence where Self.Element == UInt8 {
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/**
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A non-blocking sequence of newline-separated `Strings` created by decoding the elements of `self` as UTF8.
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*/
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@available(macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0, *)
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var lines: AsyncLineSequence<Self> {
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AsyncLineSequence(underlyingSequence: self)
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}
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}

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