wehub-resource-sync
134 lines
4.4 KiB
Swift
134 lines
4.4 KiB
Swift
//===----------------------------------------------------------------------===//
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// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//===----------------------------------------------------------------------===//
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import ContainerizationOS
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import Foundation
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import NIO
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/// `ReadStream` is a utility type for streaming data from a `URL`
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/// or `Data` blob.
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public class ReadStream {
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public static let bufferSize = Int(1.mib())
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private var _stream: InputStream
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private let buffSize: Int
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private let data: Data?
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private let url: URL?
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public init() {
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_stream = InputStream(data: .init())
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buffSize = Self.bufferSize
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self.data = Data()
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self.url = nil
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}
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public init(url: URL, bufferSize: Int = bufferSize) throws {
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guard FileManager.default.fileExists(atPath: url.path) else {
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throw Error.noSuchFileOrDirectory(url)
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}
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guard let stream = InputStream(url: url) else {
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throw Error.failedToCreateStream
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}
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self._stream = stream
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self.buffSize = bufferSize
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self.url = url
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self.data = nil
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}
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public init(data: Data, bufferSize: Int = bufferSize) {
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self._stream = InputStream(data: data)
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self.buffSize = bufferSize
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self.url = nil
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self.data = data
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}
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/// Resets the read stream. This either reassigns
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/// the data buffer or url to a new InputStream internally.
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public func reset() throws {
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self._stream.close()
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if let url = self.url {
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guard let s = InputStream(url: url) else {
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throw Error.failedToCreateStream
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}
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self._stream = s
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return
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}
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let data = self.data ?? Data()
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self._stream = InputStream(data: data)
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}
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/// Get access to an `AsyncStream` of `ByteBuffer`'s from the input source.
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public var stream: AsyncStream<ByteBuffer> {
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AsyncStream { cont in
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self._stream.open()
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defer { self._stream.close() }
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let readBuffer = UnsafeMutablePointer<UInt8>.allocate(capacity: buffSize)
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while true {
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let byteRead = self._stream.read(readBuffer, maxLength: buffSize)
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if byteRead <= 0 {
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readBuffer.deallocate()
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cont.finish()
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break
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} else {
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let data = Data(bytes: readBuffer, count: byteRead)
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let buffer = ByteBuffer(bytes: data)
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cont.yield(buffer)
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}
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}
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}
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}
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/// Get access to an `AsyncStream` of `Data` objects from the input source.
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public var dataStream: AsyncStream<Data> {
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AsyncStream { cont in
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self._stream.open()
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defer { self._stream.close() }
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let readBuffer = UnsafeMutablePointer<UInt8>.allocate(capacity: self.buffSize)
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while true {
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let byteRead = self._stream.read(readBuffer, maxLength: self.buffSize)
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if byteRead <= 0 {
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readBuffer.deallocate()
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cont.finish()
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break
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} else {
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let data = Data(bytes: readBuffer, count: byteRead)
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cont.yield(data)
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}
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}
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}
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}
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}
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extension ReadStream {
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/// Errors that can be encountered while using a `ReadStream`.
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public enum Error: Swift.Error, CustomStringConvertible {
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case failedToCreateStream
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case noSuchFileOrDirectory(_ p: URL)
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public var description: String {
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switch self {
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case .failedToCreateStream:
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return "failed to create stream"
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case .noSuchFileOrDirectory(let p):
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return "no such file or directory: \(p.path)"
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}
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}
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}
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}
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