feat: support root attributes propagation

Author: portellaa

Sources/XMLCoder/Auxiliaries/XMLCoderElement.swift

@@ -293,21 +293,23 @@ struct XMLCoderElement: Equatable {
 // MARK: - Convenience Initializers
 
 extension XMLCoderElement {
-    init(key: String, box: UnkeyedBox) {
+    init(key: String, box: UnkeyedBox, attributes: [Attribute] = []) {
         if let containsChoice = box as? [ChoiceBox] {
-            self.init(key: key, elements: containsChoice.map {
-                XMLCoderElement(key: $0.key, box: $0.element)
-            })
+            self.init(
+                key: key,
+                elements: containsChoice.map { XMLCoderElement(key: $0.key, box: $0.element) },
+                attributes: attributes
+            )
         } else {
-            self.init(key: key, elements: box.map { XMLCoderElement(key: key, box: $0) })
+            self.init(key: key, elements: box.map { XMLCoderElement(key: key, box: $0) }, attributes: attributes)
         }
     }
 
-    init(key: String, box: ChoiceBox) {
-        self.init(key: key, elements: [XMLCoderElement(key: box.key, box: box.element)])
+    init(key: String, box: ChoiceBox, attributes: [Attribute] = []) {
+        self.init(key: key, elements: [XMLCoderElement(key: box.key, box: box.element)], attributes: attributes)
     }
 
-    init(key: String, box: KeyedBox) {
+    init(key: String, box: KeyedBox, attributes: [Attribute] = []) {
         var elements: [XMLCoderElement] = []
 
         for (key, box) in box.elements {
@@ -338,7 +340,7 @@ extension XMLCoderElement {
             }
         }
 
-        let attributes: [Attribute] = box.attributes.compactMap { key, box in
+        let attributes: [Attribute] = attributes + box.attributes.compactMap { key, box in
             guard let value = box.xmlString else {
                 return nil
             }
@@ -348,30 +350,30 @@ extension XMLCoderElement {
         self.init(key: key, elements: elements, attributes: attributes)
     }
 
-    init(key: String, box: SimpleBox) {
+    init(key: String, box: SimpleBox, attributes: [Attribute] = []) {
         if let value = box.xmlString {
-            self.init(key: key, stringValue: value)
+            self.init(key: key, stringValue: value, attributes: attributes)
         } else {
-            self.init(key: key)
+            self.init(key: key, attributes: attributes)
         }
     }
 
-    init(key: String, box: Box) {
+    init(key: String, box: Box, attributes: [Attribute] = []) {
         switch box {
         case let sharedUnkeyedBox as SharedBox<UnkeyedBox>:
-            self.init(key: key, box: sharedUnkeyedBox.unboxed)
+            self.init(key: key, box: sharedUnkeyedBox.unboxed, attributes: attributes)
         case let sharedKeyedBox as SharedBox<KeyedBox>:
-            self.init(key: key, box: sharedKeyedBox.unboxed)
+            self.init(key: key, box: sharedKeyedBox.unboxed, attributes: attributes)
         case let sharedChoiceBox as SharedBox<ChoiceBox>:
-            self.init(key: key, box: sharedChoiceBox.unboxed)
+            self.init(key: key, box: sharedChoiceBox.unboxed, attributes: attributes)
         case let unkeyedBox as UnkeyedBox:
-            self.init(key: key, box: unkeyedBox)
+            self.init(key: key, box: unkeyedBox, attributes: attributes)
         case let keyedBox as KeyedBox:
-            self.init(key: key, box: keyedBox)
+            self.init(key: key, box: keyedBox, attributes: attributes)
         case let choiceBox as ChoiceBox:
-            self.init(key: key, box: choiceBox)
+            self.init(key: key, box: choiceBox, attributes: attributes)
         case let simpleBox as SimpleBox:
-            self.init(key: key, box: simpleBox)
+            self.init(key: key, box: simpleBox, attributes: attributes)
         case let box:
             preconditionFailure("Unclassified box: \(type(of: box))")
         }

Sources/XMLCoder/Encoder/XMLEncoder.swift

@@ -318,28 +318,30 @@ open class XMLEncoder {
     ///
     /// - parameter value: The value to encode.
     /// - parameter withRootKey: the key used to wrap the encoded values.
+    /// - parameter rootAttributes: the list of attributes to be added to root node
     /// - returns: A new `Data` value containing the encoded XML data.
     /// - throws: `EncodingError.invalidValue` if a non-conforming
     /// floating-point value is encountered during encoding, and the encoding
     /// strategy is `.throw`.
     /// - throws: An error if any value throws an error during encoding.
-    open func encode<T: Encodable>(_ value: T, withRootKey rootKey: String, header: XMLHeader? = nil) throws -> Data {
+    open func encode<T: Encodable>(_ value: T, withRootKey rootKey: String, rootAttributes: [String : String], header: XMLHeader? = nil) throws -> Data {
         let encoder = XMLEncoderImplementation(
             options: options,
             nodeEncodings: []
         )
         encoder.nodeEncodings.append(options.nodeEncodingStrategy.nodeEncodings(forType: T.self, with: encoder))
 
         let topLevel = try encoder.box(value)
+        let attributes = rootAttributes.map(Attribute.init)
 
         let elementOrNone: XMLCoderElement?
 
         if let keyedBox = topLevel as? KeyedBox {
-            elementOrNone = XMLCoderElement(key: rootKey, box: keyedBox)
+            elementOrNone = XMLCoderElement(key: rootKey, box: keyedBox, attributes: attributes)
         } else if let unkeyedBox = topLevel as? UnkeyedBox {
-            elementOrNone = XMLCoderElement(key: rootKey, box: unkeyedBox)
+            elementOrNone = XMLCoderElement(key: rootKey, box: unkeyedBox, attributes: attributes)
         } else if let choiceBox = topLevel as? ChoiceBox {
-            elementOrNone = XMLCoderElement(key: rootKey, box: choiceBox)
+            elementOrNone = XMLCoderElement(key: rootKey, box: choiceBox, attributes: attributes)
         } else {
             fatalError("Unrecognized top-level element of type: \(type(of: topLevel))")
         }