improvements to XML schema handling

Libraries/UniversalEditor.Essential/DataFormats/Markup/XML/CommonXMLSchemas.cs

@@ -0,0 +1,62 @@
+//
+//  XMLSchemas.cs - provides common XML schema definitions used in a wide variety of applications
+//
+//  Author:
+//       Michael Becker <alcexhim@gmail.com>
+//
+//  Copyright (c) 2021 Mike Becker's Software
+//
+//  This program is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+using System;
+namespace UniversalEditor.DataFormats.Markup.XML
+{
+	/// <summary>
+	/// Provides common XML schema definitions used in a wide variety of applications.
+	/// </summary>
+	public static class CommonXMLSchemas
+	{
+		/// <summary>
+		/// The /elements/1.1/ namespace was created in 2000 for the RDF representation of the fifteen-element
+		/// Dublin Core and has been widely used in data for more than twenty years. This namespace corresponds
+		/// to the original scope of ISO 15836, which was published first in 2003 and last revised in 2017 as
+		/// ISO 15836-1:2017.
+		/// </summary>
+		/// <value>The XML schema for the original Dublin Core namespace.</value>
+		public static string DublinCore { get; } = "http://purl.org/dc/elements/1.1/";
+		/// <summary>
+		/// The /terms/ namespace was originally created in 2001 for identifying new terms coined outside of the
+		/// original fifteen-element Dublin Core. In 2008, in the context of defining formal semantic constraints
+		/// for DCMI metadata terms in support of RDF applications, the original fifteen elements themselves were
+		/// mirrored in the /terms/ namespace. As a result, there exists both a dc:date (http://purl.org/dc/elements/1.1/date)
+		/// with no formal range and a corresponding dcterms:date (http://purl.org/dc/terms/date) with a formal
+		/// range of "literal". While these distinctions are significant for creators of RDF applications, most users
+		/// can safely treat the fifteen parallel properties as equivalent. The most useful properties and classes of
+		/// DCMI Metadata Terms have now been published as ISO 15836-2:2019 [ISO 15836-2:2019]. While the /elements/1.1/
+		/// namespace will be supported indefinitely, DCMI gently encourages use of the /terms/ namespace.
+		/// </summary>
+		/// <value>The XML schema for the Dublin Core Terms namespace.</value>
+		public static string DublinCoreTerms { get; } = "http://purl.org/dc/terms/";
+		/// <summary>
+		/// The /dcmitype/ namespace was created in 2001 for the DCMI Type Vocabulary, which defines classes for
+		/// basic types of thing that can be described using DCMI metadata terms.
+		/// </summary>
+		/// <value>The XML schema for the Dublin Core DCMI Type namespace.</value>
+		public static string DublinCoreDCMIType { get; } = "http://purl.org/dc/dcmitype/";
+		/// <summary>
+		/// The /dcam/ namespace was created in 2008 for terms used in the description of DCMI metadata terms.
+		/// </summary>
+		/// <value>The XML schema for the Dublin Core DCAM namespace.</value>
+		public static string DublinCoreDCAM { get; } = "http://purl.org/dc/dcam/";
+	}
+}

Libraries/UniversalEditor.Essential/DataFormats/Markup/XML/XMLDataFormat.cs

@@ -21,7 +21,7 @@
 
 using System;
 using System.Collections.Generic;
-
+using System.Text;
 using UniversalEditor.ObjectModels.Markup;
 using UniversalEditor.ObjectModels.PropertyList;
 
@@ -116,7 +116,7 @@ namespace UniversalEditor.DataFormats.Markup.XML
 						if (element is MarkupTagElement)
 						{
 							MarkupTagElement tag = element as MarkupTagElement;
-							tw.Write(indent + Settings.TagBeginChar.ToString() + element.FullName);
+							tw.Write(indent + Settings.TagBeginChar.ToString() + GetFullName(element));
 							if (tag.Attributes.Count > 0)
 							{
 								tw.Write(" ");
@@ -199,6 +199,40 @@ namespace UniversalEditor.DataFormats.Markup.XML
 				}
 			}
 		}
+
+		private string GetFullName(MarkupElement element)
+		{
+			if (element is MarkupTagElement)
+			{
+				if ((element as MarkupTagElement).XMLSchema != null)
+				{
+					StringBuilder sb = new StringBuilder();
+					sb.Append(GetPrefixForXMLSchema(element.ParentObjectModel, (element as MarkupTagElement).XMLSchema));
+					sb.Append(':');
+					sb.Append(element.Name);
+					return sb.ToString();
+				}
+			}
+			return element.FullName;
+		}
+
+		private string GetPrefixForXMLSchema(MarkupObjectModel mom, string xmlSchema)
+		{
+			foreach (MarkupElement el in mom.Elements)
+			{
+				if (el is MarkupTagElement)
+				{
+					foreach (MarkupAttribute att in (el as MarkupTagElement).Attributes)
+					{
+						if (att.Namespace == "xmlns" && att.Value == xmlSchema)
+							return att.Name;
+					}
+					break;
+				}
+			}
+			throw new InvalidOperationException(String.Format("xml prefix not found for schema '{0}'", xmlSchema));
+		}
+
 		public void WriteStartDocument()
 		{
 			this.WriteStartPreprocessor("xml");

Libraries/UniversalEditor.Essential/ObjectModels/Markup/MarkupContainerElement.cs

@@ -83,10 +83,14 @@ namespace UniversalEditor.ObjectModels.Markup
 			return basetag;
 		}
 
+		private string _XMLSchema = null;
 		public string XMLSchema
 		{
 			get
 			{
+				if (_XMLSchema != null)
+					return _XMLSchema;
+
 				if (this.Namespace == null)
 					return null;
 
@@ -103,6 +107,33 @@ namespace UniversalEditor.ObjectModels.Markup
 
 				return null;
 			}
+			set
+			{
+				if (this.ParentObjectModel == null)
+				{
+					_XMLSchema = value;
+					return;
+				}
+
+				for (int i = 0; i < this.ParentObjectModel.Elements.Count; i++)
+				{
+					MarkupTagElement tagTopLevel = (this.ParentObjectModel.Elements[i] as MarkupTagElement);
+					if (tagTopLevel == null)
+						continue;
+
+					foreach (MarkupAttribute att in tagTopLevel.Attributes)
+					{
+						if (att.Namespace == "xmlns")
+						{
+							if (att.Value == value)
+							{
+								Namespace = att.Name;
+								break;
+							}
+						}
+					}
+				}
+			}
 		}
 
 		protected override void UpdateParentObjectModel()

Libraries/UniversalEditor.Essential/ObjectModels/Markup/MarkupTagElement.cs

@@ -29,6 +29,21 @@ namespace UniversalEditor.ObjectModels.Markup
 	/// </summary>
 	public class MarkupTagElement : MarkupContainerElement
 	{
+		public MarkupTagElement()
+		{
+		}
+		public MarkupTagElement(string fullName, string innerMarkup)
+		{
+			FullName = fullName;
+			Value = innerMarkup;
+		}
+		public MarkupTagElement(string schema, string name, string innerMarkup)
+		{
+			XMLSchema = schema;
+			Name = name;
+			Value = innerMarkup;
+		}
+
 		/// <summary>
 		/// Combines the attributes and child elements of this <see cref="MarkupTagElement" /> with the given <see cref="MarkupElement" />.
 		/// </summary>

Libraries/UniversalEditor.Essential/UniversalEditor.Essential.csproj

@@ -217,6 +217,7 @@
     <Compile Include="DataFormats\Package\OpenDocument\Internal\ManifestXML\ManifestXMLObjectModel.cs" />
     <Compile Include="DataFormats\Package\OpenDocument\Internal\ManifestXML\ManifestFileEntry.cs" />
     <Compile Include="DataFormats\Package\OpenDocument\Internal\ManifestXML\XMLSchemas.cs" />
+    <Compile Include="DataFormats\Markup\XML\CommonXMLSchemas.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\UniversalEditor.Core\UniversalEditor.Core.csproj">