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//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2024 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
// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
//
#if canImport(Foundation)
private import Foundation
#endif
enum JSON {
/// Whether or not pretty-printed JSON is enabled for this process.
///
/// This is a debugging tool that can be used by developers working on the
/// testing library to improve the readability of JSON output.
private static let _prettyPrintingEnabled = Environment.flag(named: "SWT_PRETTY_PRINT_JSON") == true
/// Encode a value as JSON.
///
/// - Parameters:
/// - value: The value to encode.
/// - userInfo: Any user info to pass into the encoder during encoding.
/// - body: A function to call.
///
/// - Returns: Whatever is returned by `body`.
///
/// - Throws: Whatever is thrown by `body` or by the encoding process.
static func withEncoding<R>(of value: some Encodable, userInfo: [CodingUserInfoKey: Any] = [:], _ body: (UnsafeRawBufferPointer) throws -> R) throws -> R {
#if canImport(Foundation)
let encoder = JSONEncoder()
// Keys must be sorted to ensure deterministic matching of encoded data.
encoder.outputFormatting.insert(.sortedKeys)
if _prettyPrintingEnabled {
encoder.outputFormatting.insert(.prettyPrinted)
encoder.outputFormatting.insert(.withoutEscapingSlashes)
}
// Set user info keys that clients want to use during encoding.
encoder.userInfo.merge(userInfo, uniquingKeysWith: { _, rhs in rhs})
let data = try encoder.encode(value)
return try data.withUnsafeBytes(body)
#else
throw SystemError(description: "JSON encoding requires Foundation which is not available in this environment.")
#endif
}
/// Decode a value from JSON data.
///
/// - Parameters:
/// - type: The type of value to decode.
/// - jsonRepresentation: The JSON encoding of the value to decode.
///
/// - Returns: An instance of `T` decoded from `jsonRepresentation`.
///
/// - Throws: Whatever is thrown by the decoding process.
static func decode<T>(_ type: T.Type, from jsonRepresentation: UnsafeRawBufferPointer) throws -> T where T: Decodable {
#if canImport(Foundation)
try withExtendedLifetime(jsonRepresentation) {
let byteCount = jsonRepresentation.count
let data = if byteCount > 0 {
Data(
bytesNoCopy: .init(mutating: jsonRepresentation.baseAddress!),
count: byteCount,
deallocator: .none
)
} else {
Data()
}
return try JSONDecoder().decode(type, from: data)
}
#else
throw SystemError(description: "JSON decoding requires Foundation which is not available in this environment.")
#endif
}
}
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