GH-41804: [Swift] Add Struct (Nested) type (#43082)

### Rationale for this change
Nested types are needed in order to implement Struct types.

### What changes are included in this PR?
This change adds the Nested type and a method for type lookup that will be used for building Struct types.

* GitHub Issue: #41804

Authored-by: Alva Bandy <abandy@live.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>

swift/Arrow/Sources/Arrow/ArrowData.swift

@@ -39,6 +39,10 @@ public class ArrowData {
  if typeId == ArrowTypeId.unknown {
  throw ArrowError.unknownType("Unknown time type for data")
  }
+ case let .complexInfo(typeId):
+ if typeId == ArrowTypeId.unknown {
+ throw ArrowError.unknownType("Unknown complex type for data")
+ }
  }
 
  self.type = arrowType

swift/Arrow/Sources/Arrow/ArrowType.swift

@@ -122,6 +122,14 @@ public class ArrowTypeTime64: ArrowType {
  }
 }
 
+public class ArrowNestedType: ArrowType {
+ let fields: [ArrowField]
+ public init(_ info: ArrowType.Info, fields: [ArrowField]) {
+ self.fields = fields
+ super.init(info)
+ }
+}
+
 public class ArrowType {
  public private(set) var info: ArrowType.Info
  public static let ArrowInt8 = Info.primitiveInfo(ArrowTypeId.int8)
@@ -142,6 +150,7 @@ public class ArrowType {
  public static let ArrowBinary = Info.variableInfo(ArrowTypeId.binary)
  public static let ArrowTime32 = Info.timeInfo(ArrowTypeId.time32)
  public static let ArrowTime64 = Info.timeInfo(ArrowTypeId.time64)
+ public static let ArrowStruct = Info.complexInfo(ArrowTypeId.strct)
 
  public init(_ info: ArrowType.Info) {
  self.info = info
@@ -155,13 +164,51 @@ public class ArrowType {
  return id
  case .variableInfo(let id):
  return id
+ case .complexInfo(let id):
+ return id
  }
  }
 
  public enum Info {
  case primitiveInfo(ArrowTypeId)
  case variableInfo(ArrowTypeId)
  case timeInfo(ArrowTypeId)
+ case complexInfo(ArrowTypeId)
+ }
+
+ public static func infoForType( // swiftlint:disable:this cyclomatic_complexity
+ _ type: Any.Type) -> ArrowType.Info {
+ if type == String.self {
+ return ArrowType.ArrowString
+ } else if type == Date.self {
+ return ArrowType.ArrowDate64
+ } else if type == Bool.self {
+ return ArrowType.ArrowBool
+ } else if type == Data.self {
+ return ArrowType.ArrowBinary
+ } else if type == Int8.self {
+ return ArrowType.ArrowInt8
+ } else if type == Int16.self {
+ return ArrowType.ArrowInt16
+ } else if type == Int32.self {
+ return ArrowType.ArrowInt32
+ } else if type == Int64.self {
+ return ArrowType.ArrowInt64
+ } else if type == UInt8.self {
+ return ArrowType.ArrowUInt8
+ } else if type == UInt16.self {
+ return ArrowType.ArrowUInt16
+ } else if type == UInt32.self {
+ return ArrowType.ArrowUInt32
+ } else if type == UInt64.self {
+ return ArrowType.ArrowUInt64
+ } else if type == Float.self {
+ return ArrowType.ArrowFloat
+ } else if type == Double.self {
+ return ArrowType.ArrowDouble
+ } else {
+ return ArrowType.ArrowUnknown
+ }
  }
 
  public static func infoForNumericType<T>(_ type: T.Type) -> ArrowType.Info {
@@ -227,6 +274,8 @@ public class ArrowType {
  return MemoryLayout<Int8>.stride
  case .string:
  return MemoryLayout<Int8>.stride
+ case .strct:
+ return 0
  default:
  fatalError("Stride requested for unknown type: \(self)")
  }
@@ -351,3 +400,4 @@ func getBytesFor<T>(_ data: T) -> Data? {
  return nil
  }
 }
+// swiftlint:disable:this file_length