Include base classes with LINQ generation (#1838)

This change adds support to the LINQ generator to include base classes
and their members so it'll be similar to what was in the 2.x version:

- Refactor LINQ generator to use a visitor pattern
- Add SdtElement expansion
- Visit base types

Part of #1813

gen/DocumentFormat.OpenXml.Generator.Models/Generators/Linq/FieldInfo.cs

@@ -0,0 +1,189 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using DocumentFormat.OpenXml.Generator.Models;
+
+namespace DocumentFormat.OpenXml.Generator;
+
+/// <summary>
+/// Represents an XName field.
+/// </summary>
+internal class FieldInfo : IComparable<FieldInfo>, IEquatable<FieldInfo>
+{
+    private const string EmptyNamespace = "NoNamespace";
+
+    private readonly OpenXmlGeneratorServices _services;
+
+    private readonly HashSet<SchemaType> _elementMetadata = new();
+    private readonly HashSet<SchemaType> _parentMetadata = new();
+    private readonly HashSet<SchemaType> _childMetadata = new();
+
+    private readonly HashSet<SchemaType> _attributeContainerMetadata = new();
+    private readonly HashSet<SchemaAttribute> _attributeMetadata = new();
+
+    private readonly SortedSet<string> _attributePropertyNames = new();
+
+    /// <summary>
+    /// Initializes a new instance with the given <see cref="QName" />.
+    /// </summary>
+    /// <param name="qName">The <see cref="QName" />.</param>
+    public FieldInfo(QName qName, OpenXmlGeneratorServices services)
+    {
+        QName = qName;
+        FieldName = qName.Name;
+        _services = services;
+    }
+
+    /// <summary>
+    /// Gets the <see cref="QName" />.
+    /// </summary>
+    public QName QName { get; }
+
+    /// <summary>
+    /// Gets or sets the field name, e.g., "document".
+    /// </summary>
+    public string FieldName { get; set; }
+
+    /// <summary>
+    /// Gets the qualified field name, e.g., "W.document".
+    /// </summary>
+    public string QualifiedFieldName =>
+        Prefix != string.Empty
+            ? Prefix.ToUpperInvariant() + "." + FieldName
+            : EmptyNamespace + "." + FieldName;
+
+    /// <summary>
+    /// Gets the XML prefix, e.g., "w".
+    /// </summary>
+    public string Prefix => QName.Prefix;
+
+    /// <summary>
+    /// Gets the XML namespace name, e.g., "http://schemas.openxmlformats.org/wordprocessingml/2006/main".
+    /// </summary>
+    public string NamespaceName => _services.GetNamespaceInfo(QName.Prefix).Uri;
+
+    /// <summary>
+    ///  Gets the XML local name, e.g., "document".
+    /// </summary>
+    public string LocalName => QName.Name;
+
+    /// <summary>
+    /// Gets the XML qualified name, e.g., "w:document".
+    /// </summary>
+    public string QualifiedName => string.IsNullOrEmpty(Prefix) ? LocalName : Prefix + ":" + LocalName;
+
+    public IEnumerable<QName> ParentQualifiedNames =>
+        _parentMetadata
+            .OrderBy(GetQualifiedName)
+            .Select(em => em.Name.QName)
+            .Distinct();
+
+    public IEnumerable<QName> ChildQualifiedNames =>
+        _childMetadata
+            .OrderBy(GetQualifiedName)
+            .Select(em => em.Name.QName)
+            .Distinct();
+
+    public IEnumerable<QName> AttributeContainerQualifiedNames =>
+        _attributeContainerMetadata
+            .OrderBy(GetQualifiedName)
+            .Select(em => em.Name.QName)
+            .Distinct();
+
+    public IEnumerable<QName> ElementAttributeQualifiedNames =>
+        _elementMetadata
+            .SelectMany(em => em.Attributes)
+            .OrderBy(GetQualifiedName)
+            .Select(am => am.QName)
+            .Distinct();
+
+    public IEnumerable<string> ElementClassNames =>
+       _elementMetadata
+            .Select(e => _services.FindClassName(e.Name, fullyQualified: false))
+            .Distinct()
+            .OrderBy(name => name);
+
+    public IEnumerable<string> AttributePropertyNames => _attributePropertyNames;
+
+    private static string GetQualifiedName(SchemaType metadata)
+    {
+        return GetQualifiedName(metadata.Name.QName);
+    }
+
+    private static string GetQualifiedName(SchemaAttribute metadata)
+    {
+        return GetQualifiedName(metadata.QName);
+    }
+
+    private static string GetQualifiedName(QName qName)
+        => qName.ToString();
+
+    public void AddElementMetadata(SchemaType element)
+    {
+        _elementMetadata.Add(element);
+    }
+
+    public void AddParentElementMetadata(SchemaType? parent)
+    {
+        if (parent is not null)
+        {
+            _parentMetadata.Add(parent);
+        }
+    }
+
+    public void AddChildElementMetadata(SchemaType child)
+    {
+        _childMetadata.Add(child);
+    }
+
+    public void AddAttributeMetadata(SchemaType element, SchemaAttribute attribute)
+    {
+        _attributeContainerMetadata.Add(element);
+        _attributeMetadata.Add(attribute);
+
+        var className = _services.FindClassName(element.Name, fullyQualified: false);
+        _attributePropertyNames.Add(className + "." + attribute.PropertyName);
+    }
+
+    /// <inheritdoc />
+    public int CompareTo(FieldInfo? other)
+    {
+        return other is null ? 1 : QName.CompareTo(other.QName);
+    }
+
+    /// <inheritdoc />
+    public bool Equals(FieldInfo? other)
+        => other is not null && QName.Equals(other.QName);
+
+    /// <inheritdoc />
+    public override bool Equals(object? obj)
+    {
+        if (obj is null)
+        {
+            return false;
+        }
+
+        if (ReferenceEquals(this, obj))
+        {
+            return true;
+        }
+
+        return obj.GetType() == GetType() && Equals((FieldInfo)obj);
+    }
+
+    /// <inheritdoc />
+    public override int GetHashCode()
+    {
+        return QName.GetHashCode();
+    }
+
+    public static bool operator ==(FieldInfo? left, FieldInfo? right)
+    {
+        return Equals(left, right);
+    }
+
+    public static bool operator !=(FieldInfo? left, FieldInfo? right)
+    {
+        return !Equals(left, right);
+    }
+}