grpc-swift/Packages/QuickProto/Sources/MessageDescriptor.swift

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import Foundation

/// A description of a protocol buffer message
public class MessageDescriptor {
  var name: String = ""
  var fieldDescriptors: [FieldDescriptor] = []
  var nestedTypes: [MessageDescriptor] = []

  init(message:Message) { // the message should be a DescriptorProto (descriptor.proto)
    if let field = message.oneField("name") {
      name = field.string()
    }
    message.forEachField("field") {(field) in
      let fieldDescriptor = FieldDescriptor(message:field.message())
      fieldDescriptors.append(fieldDescriptor)
    }
    message.forEachField("nested_type") {(field) in
      let nestedType = MessageDescriptor(message:field.message())
      nestedTypes.append(nestedType)
    }
  }

  init(description:[String:Any]) {
    let name = (description["name"] as? String)!
    self.name = name
    let fieldDescriptions = description["fields"] as! [[String:Any]]
    for fieldDescription in fieldDescriptions {
      var typeName = ""
      if fieldDescription["type_name"] != nil {
        typeName = fieldDescription["type_name"] as! String
      }
      let parts = typeName.components(separatedBy: ".")
      typeName = parts.last!
      self.fieldDescriptors.append(FieldDescriptor(type: fieldDescription["type"] as! Int,
                                                   name: fieldDescription["name"] as! String,
                                                   tag: fieldDescription["number"] as! Int,
                                                   type_name: typeName,
                                                   label: fieldDescription["label"] as! Int
      ))
    }
  }

  /// lookup the field descriptor for a specified tag
  func fieldDescriptor(tag: Int) -> FieldDescriptor? {
    for fieldDescriptor in fieldDescriptors {
      if (fieldDescriptor.tag == tag) {
        return fieldDescriptor
      }
    }
    print("UNRECOGNIZED \(name):\(tag)")
    return nil
  }
}