Repository: apple/swift-nio
File: Sources/NIOCore/ByteBuffer-hex.swift (Swift)

Code before:
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2023 Apple Inc. and the SwiftNIO project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//

extension ByteBuffer {

    /// Create a fresh `ByteBuffer` containing the `bytes` decoded from  the string representation of `hexEncodedBytes`.
    ///
    /// This will allocate a new `ByteBuffer` with enough space to fit the hex decoded `bytes` and potentially some extra space
    /// using the default allocator.
    ///
    /// - info: If you have access to a `Channel`, `ChannelHandlerContext`, or `ByteBufferAllocator` we
    ///         recommend using `channel.allocator.buffer(integer:)`. Or if you want to write multiple items into the
    ///         buffer use `channel.allocator.buffer(capacity: ...)` to allocate a `ByteBuffer` of the right
    ///         size followed by a `writeHexEncodedBytes` instead of using this method. This allows SwiftNIO to do
    ///         accounting and optimisations of resources acquired for operations on a given `Channel` in the future.
    init(hexEncodedBytes string: String) {
        var buffer = ByteBuffer()
        buffer.writeHexEncodedBytes(string)
        self = buffer
    }

    /// Describes a ByteBuffer hexDump format.
    /// Can be either xxd output compatible, or hexdump compatible.
    public struct HexDumpFormat: Hashable, Sendable {

        enum Value: Hashable {
            case plain(maxBytes: Int? = nil)
            case detailed(maxBytes: Int? = nil)
        }

        let value: Value
        init(_ value: Value) { self.value = value }

        /// A plain hex dump format compatible with `xxd` CLI utility.
        public static let plain = Self(.plain(maxBytes: nil))

        /// A hex dump format compatible with `hexdump` command line utility.
        public static let detailed = Self(.detailed(maxBytes: nil))

        /// A detailed hex dump format compatible with `xxd`, clipped to `maxBytes` bytes dumped.
        /// This format will dump first `maxBytes / 2` bytes, and the last `maxBytes / 2` bytes, replacing the rest with " ... ".

Review comment (refactor):
You right pointed out that we need to move this to `ByteBufferAllocator`, and then have this method call that one.

Code after:
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2023 Apple Inc. and the SwiftNIO project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//

extension ByteBuffer {

    /// Create a fresh `ByteBuffer` containing the `bytes` decoded from the string representation of `plainHexEncodedBytes`.
    ///
    /// This will allocate a new `ByteBuffer` with enough space to fit the hex decoded `bytes` and potentially some extra space
    /// using the default allocator.
    ///
    /// - info: If you have access to a `Channel`, `ChannelHandlerContext`, or `ByteBufferAllocator` we
    ///         recommend using `channel.allocator.buffer(integer:)`. Or if you want to write multiple items into the
    ///         buffer use `channel.allocator.buffer(capacity: ...)` to allocate a `ByteBuffer` of the right
    ///         size followed by a `writeHexEncodedBytes` instead of using this method. This allows SwiftNIO to do
    ///         accounting and optimisations of resources acquired for operations on a given `Channel` in the future.
    public init(plainHexEncodedBytes string: String) throws {
        self = try ByteBufferAllocator().buffer(plainHexEncodedBytes: string)
    }

    /// Describes a ByteBuffer hexDump format.
    /// Can be either xxd output compatible, or hexdump compatible.
    public struct HexDumpFormat: Hashable, Sendable {

        enum Value: Hashable {
            case plain(maxBytes: Int? = nil)
            case detailed(maxBytes: Int? = nil)
            case compact(maxBytes: Int? = nil)
        }

        let value: Value
        init(_ value: Value) { self.value = value }

        /// A plain hex dump format compatible with `xxd` CLI utility.
        public static let plain = Self(.plain(maxBytes: nil))

        /// A hex dump format compatible with `hexdump` command line utility.
        public static let detailed = Self(.detailed(maxBytes: nil))

        /// A hex dump analog to `plain` format  but without whitespaces.
        public static let compact = Self(.compact(maxBytes: nil))