Used vendored base64 encoding implementation rather than Foundation.Data

Author: karwa

Sources/AsyncHTTPClient/Base64.swift

@@ -0,0 +1,174 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the AsyncHTTPClient open source project
+//
+// Copyright (c) 2021 Apple Inc. and the AsyncHTTPClient project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of AsyncHTTPClient project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+// This is a simplified vendored version from:
+// https://github.com/fabianfett/swift-base64-kit
+
+// swiftformat:disable all
+
+extension String {
+
+  /// Base64 encode a collection of UInt8 to a string, without the use of Foundation.
+  @inlinable
+  init<Buffer: Collection>(base64Encoding bytes: Buffer)
+    where Buffer.Element == UInt8
+  {
+    self = Base64.encode(bytes: bytes)
+  }
+}
+
+@usableFromInline
+internal struct Base64 {
+
+  @inlinable
+  static func encode<Buffer: Collection>(bytes: Buffer)
+    -> String where Buffer.Element == UInt8
+  {
+    guard !bytes.isEmpty else {
+        return ""
+    }
+    // In Base64, 3 bytes become 4 output characters, and we pad to the
+    // nearest multiple of four.
+    let base64StringLength = ((bytes.count + 2) / 3) * 4
+    let alphabet = Base64.encodeBase64
+
+    return String(customUnsafeUninitializedCapacity: base64StringLength) { backingStorage in
+      var input = bytes.makeIterator()
+      var offset = 0
+      while let firstByte = input.next() {
+        let secondByte = input.next()
+        let thirdByte = input.next()
+
+        backingStorage[offset] = Base64.encode(alphabet: alphabet, firstByte: firstByte)
+        backingStorage[offset + 1] = Base64.encode(alphabet: alphabet, firstByte: firstByte, secondByte: secondByte)
+        backingStorage[offset + 2] = Base64.encode(alphabet: alphabet, secondByte: secondByte, thirdByte: thirdByte)
+        backingStorage[offset + 3] = Base64.encode(alphabet: alphabet, thirdByte: thirdByte)
+        offset += 4
+      }
+      return offset
+    }
+  }
+
+  // MARK: Internal
+
+  // The base64 unicode table.
+  @usableFromInline
+  static let encodeBase64: [UInt8] = [
+    UInt8(ascii: "A"), UInt8(ascii: "B"), UInt8(ascii: "C"), UInt8(ascii: "D"),
+    UInt8(ascii: "E"), UInt8(ascii: "F"), UInt8(ascii: "G"), UInt8(ascii: "H"),
+    UInt8(ascii: "I"), UInt8(ascii: "J"), UInt8(ascii: "K"), UInt8(ascii: "L"),
+    UInt8(ascii: "M"), UInt8(ascii: "N"), UInt8(ascii: "O"), UInt8(ascii: "P"),
+    UInt8(ascii: "Q"), UInt8(ascii: "R"), UInt8(ascii: "S"), UInt8(ascii: "T"),
+    UInt8(ascii: "U"), UInt8(ascii: "V"), UInt8(ascii: "W"), UInt8(ascii: "X"),
+    UInt8(ascii: "Y"), UInt8(ascii: "Z"), UInt8(ascii: "a"), UInt8(ascii: "b"),
+    UInt8(ascii: "c"), UInt8(ascii: "d"), UInt8(ascii: "e"), UInt8(ascii: "f"),
+    UInt8(ascii: "g"), UInt8(ascii: "h"), UInt8(ascii: "i"), UInt8(ascii: "j"),
+    UInt8(ascii: "k"), UInt8(ascii: "l"), UInt8(ascii: "m"), UInt8(ascii: "n"),
+    UInt8(ascii: "o"), UInt8(ascii: "p"), UInt8(ascii: "q"), UInt8(ascii: "r"),
+    UInt8(ascii: "s"), UInt8(ascii: "t"), UInt8(ascii: "u"), UInt8(ascii: "v"),
+    UInt8(ascii: "w"), UInt8(ascii: "x"), UInt8(ascii: "y"), UInt8(ascii: "z"),
+    UInt8(ascii: "0"), UInt8(ascii: "1"), UInt8(ascii: "2"), UInt8(ascii: "3"),
+    UInt8(ascii: "4"), UInt8(ascii: "5"), UInt8(ascii: "6"), UInt8(ascii: "7"),
+    UInt8(ascii: "8"), UInt8(ascii: "9"), UInt8(ascii: "+"), UInt8(ascii: "/"),
+  ]
+
+  static let encodePaddingCharacter: UInt8 = UInt8(ascii: "=")
+
+  @usableFromInline
+  static func encode(alphabet: [UInt8], firstByte: UInt8) -> UInt8 {
+    let index = firstByte >> 2
+    return alphabet[Int(index)]
+  }
+
+  @usableFromInline
+  static func encode(alphabet: [UInt8], firstByte: UInt8, secondByte: UInt8?) -> UInt8 {
+    var index = (firstByte & 0b00000011) << 4
+    if let secondByte = secondByte {
+      index += (secondByte & 0b11110000) >> 4
+    }
+    return alphabet[Int(index)]
+  }
+
+  @usableFromInline
+  static func encode(alphabet: [UInt8], secondByte: UInt8?, thirdByte: UInt8?) -> UInt8 {
+    guard let secondByte = secondByte else {
+      // No second byte means we are just emitting padding.
+      return Base64.encodePaddingCharacter
+    }
+    var index = (secondByte & 0b00001111) << 2
+    if let thirdByte = thirdByte {
+      index += (thirdByte & 0b11000000) >> 6
+    }
+    return alphabet[Int(index)]
+  }
+
+  @usableFromInline
+  static func encode(alphabet: [UInt8], thirdByte: UInt8?) -> UInt8 {
+    guard let thirdByte = thirdByte else {
+      // No third byte means just padding.
+      return Base64.encodePaddingCharacter
+    }
+    let index = thirdByte & 0b00111111
+    return alphabet[Int(index)]
+  }
+}
+
+extension String {
+  /// This is a backport of a proposed String initializer that will allow writing directly into an uninitialized String's backing memory.
+  ///
+  /// As this API does not exist prior to 5.3 on Linux, or on older Apple platforms, we fake it out with a pointer and accept the extra copy.
+  @inlinable
+  init(backportUnsafeUninitializedCapacity capacity: Int,
+       initializingUTF8With initializer: (_ buffer: UnsafeMutableBufferPointer<UInt8>) throws -> Int) rethrows {
+    // The buffer will store zero terminated C string
+    let buffer = UnsafeMutableBufferPointer<UInt8>.allocate(capacity: capacity + 1)
+    defer {
+        buffer.deallocate()
+    }
+
+    let initializedCount = try initializer(buffer)
+    precondition(initializedCount <= capacity, "Overran buffer in initializer!")
+    // add zero termination
+    buffer[initializedCount] = 0
+
+    self = String(cString: buffer.baseAddress!)
+  }
+}
+
+// Frustratingly, Swift 5.3 shipped before the macOS 11 SDK did, so we cannot gate the availability of
+// this declaration on having the 5.3 compiler. This has caused a number of build issues. While updating
+// to newer Xcodes does work, we can save ourselves some hassle and just wait until 5.4 to get this
+// enhancement on Apple platforms.
+#if (compiler(>=5.3) && !(os(macOS) || os(iOS) || os(tvOS) || os(watchOS))) || compiler(>=5.4)
+extension String {
+
+  @inlinable
+  init(customUnsafeUninitializedCapacity capacity: Int,
+     initializingUTF8With initializer: (_ buffer: UnsafeMutableBufferPointer<UInt8>) throws -> Int) rethrows {
+    if #available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *) {
+        try self.init(unsafeUninitializedCapacity: capacity, initializingUTF8With: initializer)
+    } else {
+        try self.init(backportUnsafeUninitializedCapacity: capacity, initializingUTF8With: initializer)
+    }
+  }
+}
+#else
+extension String {
+  @inlinable
+  init(customUnsafeUninitializedCapacity capacity: Int,
+     initializingUTF8With initializer: (_ buffer: UnsafeMutableBufferPointer<UInt8>) throws -> Int) rethrows {
+    try self.init(backportUnsafeUninitializedCapacity: capacity, initializingUTF8With: initializer)
+  }
+}
+#endif

Sources/AsyncHTTPClient/HTTPHandler.swift

@@ -279,7 +279,7 @@ extension HTTPClient {
         }
 
         public static func basic(username: String, password: String) -> HTTPClient.Authorization {
-            return .basic(credentials: Data("\(username):\(password)".utf8).base64EncodedString())
+            return .basic(credentials: Base64.encode(bytes: "\(username):\(password)".utf8))
         }
 
         public static func basic(credentials: String) -> HTTPClient.Authorization {