// Sources/SwiftProtobuf/CustomJSONCodable.swift - Custom JSON support for WKTs

//

// Copyright (c) 2014 - 2017 Apple Inc. and the project authors

// Licensed under Apache License v2.0 with Runtime Library Exception

//

// See LICENSE.txt for license information:

// https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt

//

// -----------------------------------------------------------------------------

///

/// Custom protocol for the WKTs to support their custom JSON encodings.

///

// -----------------------------------------------------------------------------

/// Allows WKTs to provide their custom JSON encodings.

internal protocol _CustomJSONCodable {

  func encodedJSONString(options: JSONEncodingOptions) throws -> String

  mutating func decodeJSON(from: inout JSONDecoder) throws

  /// Called when the JSON `null` literal is encountered in a position where

  /// a message of the conforming type is expected. The message type can then

  /// handle the `null` value differently, if needed; for example,

  /// `Google_Protobuf_Value` returns a special instance whose `kind` is set to

  /// `.nullValue(.nullValue)`.

  ///

  /// The default behavior is to return `nil`, which indicates that `null`

  /// should be treated as the absence of a message.

  static func decodedFromJSONNull() throws -> Self?

}

extension _CustomJSONCodable {

  internal static func decodedFromJSONNull() -> Self? {

    // Return nil by default. Concrete types can provide custom logic.

    return nil

  }

}