Improved self-closing / empty serialization #11

Author: FlorianRappl

src/AngleSharp.Xml.Tests/Various.cs

@@ -1,4 +1,4 @@
-namespace AngleSharp.Xml.Tests
+namespace AngleSharp.Xml.Tests
 {
     using AngleSharp.Dom;
     using AngleSharp.Io;
@@ -63,6 +63,40 @@ public async Task GenerateDocumentFromSvgWithSvgContentType()
             Assert.AreEqual("path", document.DocumentElement.FirstElementChild.NodeName);
         }
 
+        [Test]
+        public void SelfClosingTagsAreSerializedCorrectlyByDefaultFormatter_Issue11()
+        {
+            var parser = new XmlParser();
+            var xmlDoc = parser.ParseDocument(
+                @"<Project Sdk=""Microsoft.NET.Sdk"">
+            <ItemGroup>
+                <PackageReference Include=""AngleSharp"" Version=""0.12.1"" />
+                <PackageReference></PackageReference>
+            </ItemGroup>
+        </Project>");
+            var xml = xmlDoc.ToXml();
+            Assert.AreEqual("<Project Sdk=\"Microsoft.NET.Sdk\">\n            <ItemGroup>\n                <PackageReference Include=\"AngleSharp\" Version=\"0.12.1\" />\n                <PackageReference></PackageReference>\n            </ItemGroup>\n        </Project>", xml);
+        }
+
+        [Test]
+        public void EmptyTagsAreSerializedCorrectlyWithStandardFormatterWithOption_Issue11()
+        {
+            var parser = new XmlParser();
+            var xmlDoc = parser.ParseDocument(
+                @"<Project Sdk=""Microsoft.NET.Sdk"">
+            <ItemGroup>
+                <PackageReference Include=""AngleSharp"" Version=""0.12.1"" />
+                <PackageReference></PackageReference>
+            </ItemGroup>
+        </Project>");
+            var formatter = new XmlMarkupFormatter
+            {
+                IsAlwaysSelfClosing = true,
+            };
+            var xml = xmlDoc.ToHtml(formatter);
+            Assert.AreEqual("<Project Sdk=\"Microsoft.NET.Sdk\">\n            <ItemGroup>\n                <PackageReference Include=\"AngleSharp\" Version=\"0.12.1\" />\n                <PackageReference />\n            </ItemGroup>\n        </Project>", xml);
+        }
+
         private static Task<IDocument> GenerateDocument(String content, String contentType)
         {
             var config = Configuration.Default.WithDefaultLoader().WithXml();

src/AngleSharp.Xml/MarkupFormatterExtensions.cs

@@ -1,6 +1,7 @@
 namespace AngleSharp.Xml
 {
     using System;
+    using System.IO;
 
     /// <summary>
     /// Extensions for the markup formattable elements.
@@ -16,6 +17,14 @@ public static class MarkupFormatterExtensions
         public static String ToXml(this IMarkupFormattable markup) =>
             markup.ToHtml(XmlMarkupFormatter.Instance);
 
+        /// <summary>
+        /// Serializes the object model guided by the XML markup formatter.
+        /// </summary>
+        /// <param name="markup">The markup to serialize.</param>
+        /// <param name="writer">The output target of the serialization.</param>
+        public static void ToXml(this IMarkupFormattable markup, TextWriter writer) =>
+            markup.ToHtml(writer, XmlMarkupFormatter.Instance);
+
         /// <summary>
         /// Returns the serialization of the object model guided by the
         /// auto selected (XML, XHTML, HTML) markup formatter.
@@ -24,5 +33,14 @@ public static String ToXml(this IMarkupFormattable markup) =>
         /// <returns>The source code snippet.</returns>
         public static String ToMarkup(this IMarkupFormattable markup) =>
             markup.ToHtml(new AutoSelectedMarkupFormatter());
+
+        /// <summary>
+        /// Serializes the object model guided by the auto selected (XML,
+        /// XHTML, HTML) markup formatter.
+        /// </summary>
+        /// <param name="markup">The markup to serialize.</param>
+        /// <param name="writer">The output target of the serialization.</param>
+        public static void ToMarkup(this IMarkupFormattable markup, TextWriter writer) =>
+            markup.ToHtml(writer, new AutoSelectedMarkupFormatter());
     }
 }

src/AngleSharp.Xml/Parser/XmlDomBuilder.cs

@@ -271,7 +271,7 @@ private void InBody(XmlToken token)
                 case XmlTokenType.StartTag:
                 {
                     var tagToken = (XmlTagToken)token;
-                    var element = CreateElement(tagToken.Name);
+                    var element = CreateElement(tagToken.Name, tagToken.IsSelfClosing);
                     CurrentNode.AppendChild(element);
 
                     for (var i = 0; i < tagToken.Attributes.Count; i++)
@@ -402,17 +402,19 @@ private void AfterBody(XmlToken token)
 
         #region Helpers
 
-        private Element CreateElement(String name)
+        private Element CreateElement(String name, Boolean selfClosing)
         {
             var prefix = default(String);
             var colon = name.IndexOf(Symbols.Colon);
+            var flags = selfClosing ? NodeFlags.SelfClosing : NodeFlags.None;
 
             if (colon > 0 && colon < name.Length - 1)
             {
                 prefix = name.Substring(0, colon);
                 name = name.Substring(colon + 1);
             }
 
+            //TODO transport flags
             return _document.CreateElementFrom(name, prefix);
         }
 

src/AngleSharp.Xml/XmlMarkupFormatter.cs

@@ -18,14 +18,25 @@ public sealed class XmlMarkupFormatter : IMarkupFormatter
 
         #endregion
 
+        #region Properties
+
+        /// <summary>
+        /// Gets or sets if empty elements should always be considered self-closing.
+        /// Otherwise, requires the element to have a self-closing flag.
+        /// </summary>
+        public Boolean IsAlwaysSelfClosing { get; set; }
+
+        #endregion
+
         #region Methods
 
         String IMarkupFormatter.CloseTag(IElement element, Boolean selfClosing)
         {
             var prefix = element.Prefix;
             var name = element.LocalName;
             var tag = !String.IsNullOrEmpty(prefix) ? String.Concat(prefix, ":", name) : name;
-            return selfClosing ? String.Empty : String.Concat("</", tag, ">");
+            var closed = selfClosing || IsAlwaysSelfClosing && !element.HasChildNodes;
+            return closed ? String.Empty : String.Concat("</", tag, ">");
         }
 
         String IMarkupFormatter.Comment(IComment comment) => String.Concat("<!--", comment.Data, "-->");
@@ -59,7 +70,7 @@ String IMarkupFormatter.OpenTag(IElement element, Boolean selfClosing)
                 temp.Append(" ").Append(Instance.Attribute(attribute));
             }
 
-            if (selfClosing)
+            if (selfClosing || (IsAlwaysSelfClosing && !element.HasChildNodes))
             {
                 temp.Append(" /");
             }