Support building on Windows.

.gitignore

@@ -3,6 +3,7 @@
 # gitignore contributors: remember to update Global/Xcode.gitignore, Objective-C.gitignore & Swift.gitignore
 
 ## Build generated
+.build/
 build/
 DerivedData
 

CMakeLists.txt

@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.19.6)
+
+project(Fuzi LANGUAGES Swift)
+
+set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+set(CMAKE_Swift_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/swift)
+
+if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
+  # LibXml2 must be built on Windows. It's preinstalled on MacOS.
+  add_subdirectory(Vendor)
+endif()
+
+add_subdirectory(Sources)

Sources/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_library(Fuzi
+  Document.swift
+  Element.swift
+  Error.swift
+  Helpers.swift
+  Node.swift
+  NodeSet.swift
+  Queryable.swift)
+
+target_link_libraries(Fuzi PUBLIC
+  LibXml2)

Sources/Document.swift

@@ -30,15 +30,13 @@ open class XMLDocument {
     return ^-^self.cDocument.pointee.version
   }()
 
-  /// The string encoding for the document. This is NSUTF8StringEncoding if no encoding is set, or it cannot be calculated.
+  /// The string encoding for the document. This is utf8 if no encoding is set, or it cannot be calculated.
   open fileprivate(set) lazy var encoding: String.Encoding = {
-    if let encodingName = ^-^self.cDocument.pointee.encoding {
-      let encoding = CFStringConvertIANACharSetNameToEncoding(encodingName as CFString?)
-      if encoding != kCFStringEncodingInvalidId {
-        return String.Encoding(rawValue: UInt(CFStringConvertEncodingToNSStringEncoding(encoding)))
-      }
+    guard let encodingStr = ^-^self.cDocument.pointee.encoding,
+          let encoding = String.Encoding(ianaCharsetName: encodingStr) else {
+      return String.Encoding.utf8
     }
-    return String.Encoding.utf8
+    return encoding
   }()
 
   // MARK: - Accessing the Root Element

Sources/Error.swift

@@ -43,7 +43,7 @@ public enum XMLError: Error {
     }
     let message = (^-^errorPtr.pointee.message)?.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
     let code = Int(errorPtr.pointee.code)
-    xmlResetError(errorPtr)
+    xmlResetError(UnsafeMutablePointer(mutating: errorPtr))
     return .libXMLError(code: code, message: message ?? "")
   }
 }

Sources/Helpers.swift

@@ -146,3 +146,48 @@ internal func cXMLNode(_ node: xmlNodePtr?, matchesTag tag: XMLCharsComparable,
   }
   return matches
 }
+
+internal extension String.Encoding {
+  // CoreFoundation is not available on Windows, so mimic the functionality
+  // of CFStringConvertIANACharSetNameToEncoding() and
+  // CFStringConvertEncodingToNSStringEncoding() here. See the IANA charset
+  // name registry at https://www.iana.org/assignments/character-sets/character-sets.xhtml
+  init?(ianaCharsetName name: String) {
+    switch name.lowercased() {
+    case "iso-2022-jp":
+      self = .iso2022JP
+    case "iso-8859-1":
+      self = .isoLatin1
+    case "iso-8859-2":
+      self = .isoLatin2
+    case "unicode-1-1", "iso-10646-ucs-2", "utf-16":
+      self = .utf16
+    case "utf-8":
+      self = .utf8
+    case "utf-16be":
+      self = .utf16BigEndian
+    case "utf-16le":
+      self = .utf16LittleEndian
+    case "utf-32":
+      self = .utf32
+    case "utf-32be":
+      self = .utf32BigEndian
+    case "utf-32le":
+      self = .utf32LittleEndian
+    case "windows-1250":
+      self = .windowsCP1250
+    case "windows-1251":
+      self = .windowsCP1251
+    case "windows-1252":
+      self = .windowsCP1252
+    case "windows-1253":
+      self = .windowsCP1253
+    case "windows-1254":
+      self = .windowsCP1254
+    case "us-ascii":
+      self = .ascii
+    default:
+      return nil
+    }
+  }
+}

Sources/Node.swift

@@ -69,7 +69,15 @@ extension XMLNodeType {
   /// XInclude End
   public static var XIncludeEnd: xmlElementType   { return XML_XINCLUDE_END }
   /// DocbDocument
-  public static var DocbDocument: xmlElementType  { return XML_DOCB_DOCUMENT_NODE }
+  public static var DocbDocument: xmlElementType  {
+    #if os(Windows)
+    // The DOCB type is not part of the enum in libxml2, it's a #define. On 
+    // Windows it gets imported as an incompatible type, so explicitly cast it.
+    return xmlElementType(XML_DOCB_DOCUMENT_NODE) 
+    #else
+    return XML_DOCB_DOCUMENT_NODE
+    #endif
+  }
 }
 
 infix operator ~=
@@ -97,7 +105,8 @@ open class XMLNode {
 
   /// The element's line number.
   open fileprivate(set) lazy var lineNumber: Int = {
-    return xmlGetLineNo(self.cNode)
+    // On Windows `long` is a 32 bit value so explicitly cast to Int.
+    return Int(xmlGetLineNo(self.cNode))
   }()
 
   // MARK: - Accessing Parent and Sibling Elements
@@ -119,7 +128,9 @@ open class XMLNode {
   // MARK: - Accessing Contents
   /// Whether this is a HTML node
   open var isHTML: Bool {
-    return UInt32(self.cNode.pointee.doc.pointee.properties) & XML_DOC_HTML.rawValue == XML_DOC_HTML.rawValue
+    // On Windows the bitset is imported as an incompatible type, so explicitly cast it.
+    let xmlDocHtmlBit = UInt32(XML_DOC_HTML.rawValue)
+    return UInt32(self.cNode.pointee.doc.pointee.properties) & xmlDocHtmlBit == xmlDocHtmlBit
   }
 
   /// A string representation of the element's value.

Vendor/CMakeLists.txt

@@ -0,0 +1,30 @@
+include(FetchContent)
+
+# Turn off noisy deprecation warnings from Microsoft.
+add_compile_definitions(_CRT_SECURE_NO_WARNINGS _CRT_NONSTDC_NO_WARNINGS)
+
+# Set libxml2 build options.
+set(LIBXML2_WITH_ICONV OFF)
+set(LIBXML2_WITH_PYTHON OFF)
+set(BUILD_SHARED_LIBS OFF)
+
+# Fetch and build libxml2.
+FetchContent_Declare(LibXml2
+  GIT_REPOSITORY "https://github.com/GNOME/libxml2.git"
+  GIT_TAG "v2.13.3")
+FetchContent_MakeAvailable(LibXml2)
+
+# libxml2 needs a modulemap to be usable from Swift. Glob the headers
+# and write one to their headers directory.
+file(GLOB LIBXML2_HEADERS "${libxml2_SOURCE_DIR}/include/libxml/*.h")
+set(MODULE_CONTENT "module libxml2 {\n")
+foreach(HEADER ${LIBXML2_HEADERS})
+  get_filename_component(HEADER_NAME ${HEADER} NAME)
+  string(APPEND MODULE_CONTENT "  header \"${HEADER_NAME}\"\n")
+endforeach()
+string(APPEND MODULE_CONTENT "  export *\n}")
+file(CONFIGURE OUTPUT ${libxml2_SOURCE_DIR}/include/libxml/module.modulemap
+  CONTENT "${MODULE_CONTENT}")
+
+# Make libxml2 available in the proper case.
+add_library(libxml2 ALIAS LibXml2)