THRIFT-3773: Swift 3 changes, Squashed (#1084)
Client: swift
diff --git a/lib/swift/Sources/TStruct.swift b/lib/swift/Sources/TStruct.swift
new file mode 100644
index 0000000..f172a32
--- /dev/null
+++ b/lib/swift/Sources/TStruct.swift
@@ -0,0 +1,100 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+
+/// Protocol for Generated Structs to conform to
+/// Dictionary maps field names to internal IDs and uses Reflection
+/// to iterate through all fields.
+/// `writeFieldValue(_:name:type:id:)` calls `TSerializable.write(to:)` internally
+/// giving a nice recursive behavior for nested TStructs, TLists, TMaps, and TSets
+public protocol TStruct : TSerializable {
+ static var fieldIds: [String: Int32] { get }
+ static var structName: String { get }
+}
+
+public extension TStruct {
+ public static var fieldIds: [String: (id: Int32, type: TType)] { return [:] }
+ public static var thriftType: TType { return .struct }
+
+ public func write(to proto: TProtocol) throws {
+ // Write struct name first
+ try proto.writeStructBegin(name: Self.structName)
+
+ try self.forEach { name, value, id in
+ // Write to protocol
+ try proto.writeFieldValue(value, name: name,
+ type: value.thriftType, id: id)
+ }
+ try proto.writeFieldStop()
+ try proto.writeStructEnd()
+ }
+
+ public var hashValue: Int {
+ let prime = 31
+ var result = 1
+ self.forEach { _, value, _ in
+ result = prime &* result &+ (value.hashValue)
+ }
+ return result
+ }
+
+ /// Provides a block for handling each (available) thrift property using reflection
+ /// Caveat: Skips over optional values
+
+
+ /// Provides a block for handling each (available) thrift property using reflection
+ ///
+ /// - parameter block: block for handling property
+ ///
+ /// - throws: rethrows any Error thrown in block
+ private func forEach(_ block: (_ name: String, _ value: TSerializable, _ id: Int32) throws -> Void) rethrows {
+ // Mirror the object, getting (name: String?, value: Any) for every property
+ let mirror = Mirror(reflecting: self)
+
+ // Iterate through all children, ignore empty property names
+ for (propName, propValue) in mirror.children {
+ guard let propName = propName else { continue }
+
+ if let tval = unwrap(any: propValue) as? TSerializable, let id = Self.fieldIds[propName] {
+ try block(propName, tval, id)
+ }
+ }
+ }
+
+
+ /// Any can mysteriously be an Optional<Any> at the same time,
+ /// this checks and always returns Optional<Any> without double wrapping
+ /// we then try to bind value as TSerializable to ignore any extension properties
+ /// and the like and verify the property exists and grab the Thrift
+ /// property ID at the same time
+ ///
+ /// - parameter any: Any instance to attempt to unwrap
+ ///
+ /// - returns: Unwrapped Any as Optional<Any>
+ private func unwrap(any: Any) -> Any? {
+ let mi = Mirror(reflecting: any)
+
+ if mi.displayStyle != .optional { return any }
+ if mi.children.count == 0 { return nil }
+
+ let (_, some) = mi.children.first!
+ return some
+ }
+}
+