Normalize newline in xml writer for csproj generation (#5768)

In support of Azure/azure-sdk-for-net#47071 we
need to normalize the line endings in our xml writer to not toggle back
and forth when sometimes generating on linux and other times on windows.

Also added some missing public docs for the visitor.

Author: m-nash

packages/http-client-csharp/generator/Microsoft.Generator.CSharp/src/LibraryVisitor.cs

@@ -7,6 +7,9 @@
 
 namespace Microsoft.Generator.CSharp
 {
+    /// <summary>
+    /// Base class for visiting and potentially modifying the output library.
+    /// </summary>
     public abstract class LibraryVisitor
     {
         internal virtual void Visit(OutputLibrary library)
@@ -100,46 +103,94 @@ internal virtual void Visit(OutputLibrary library)
             return type;
         }
 
+        /// <summary>
+        /// Visits an <see cref="InputModelType"/> and the converted <see cref="ModelProvider"/> and returns a possibly modified version of the <see cref="ModelProvider"/>.
+        /// </summary>
+        /// <param name="model">The original input model.</param>
+        /// <param name="type">The current conversion.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="ModelProvider"/>.</returns>
         protected internal virtual ModelProvider? Visit(InputModelType model, ModelProvider? type)
         {
             return type;
         }
 
+        /// <summary>
+        /// Visits an <see cref="InputModelProperty"/> and the converted <see cref="PropertyProvider"/> and returns a possibly modified version of the <see cref="PropertyProvider"/>.
+        /// </summary>
+        /// <param name="property">The original input model property.</param>
+        /// <param name="propertyProvider">The current conversion.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="PropertyProvider"/>.</returns>
         protected internal virtual PropertyProvider? Visit(InputModelProperty property, PropertyProvider? propertyProvider)
         {
             return propertyProvider;
         }
 
+        /// <summary>
+        /// Visits an <see cref="InputEnumType"/> and the converted <see cref="TypeProvider"/> and returns a possibly modified version of the <see cref="TypeProvider"/>.
+        /// </summary>
+        /// <param name="enumType">The original input enum.</param>
+        /// <param name="type">The current conversion.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="TypeProvider"/>.</returns>
         protected internal virtual TypeProvider? Visit(InputEnumType enumType, TypeProvider? type)
         {
             return type;
         }
 
+        /// <summary>
+        /// Visits a <see cref="TypeProvider"/> and returns a possibly modified version of it.
+        /// </summary>
+        /// <param name="type">The original <see cref="TypeProvider"/>.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="TypeProvider"/>.</returns>
         protected virtual TypeProvider? Visit(TypeProvider type)
         {
             return type;
         }
 
+        /// <summary>
+        /// Visits a <see cref="TypeProvider"/> after all its members have been visited and returns a possibly modified version of it.
+        /// </summary>
+        /// <param name="type">The original <see cref="TypeProvider"/>.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="TypeProvider"/>.</returns>
         protected virtual TypeProvider? PostVisit(TypeProvider type)
         {
             return type;
         }
 
+        /// <summary>
+        /// Visits a <see cref="ConstructorProvider"/> and returns a possibly modified version of it.
+        /// </summary>
+        /// <param name="constructor">The original <see cref="ConstructorProvider"/>.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="ConstructorProvider"/>.</returns>
         protected virtual ConstructorProvider? Visit(ConstructorProvider constructor)
         {
             return constructor;
         }
 
+        /// <summary>
+        /// Visits a <see cref="MethodProvider"/> and returns a possibly modified version of it.
+        /// </summary>
+        /// <param name="method">The original <see cref="MethodProvider"/>.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="MethodProvider"/>.</returns>
         protected virtual MethodProvider? Visit(MethodProvider method)
         {
             return method;
         }
 
+        /// <summary>
+        /// Visits a <see cref="PropertyProvider"/> and returns a possibly modified version of it.
+        /// </summary>
+        /// <param name="property">The original <see cref="PropertyProvider"/>.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="PropertyProvider"/>.</returns>
         protected virtual PropertyProvider? Visit(PropertyProvider property)
         {
             return property;
         }
 
+        /// <summary>
+        /// Visits a <see cref="FieldProvider"/> and returns a possibly modified version of it.
+        /// </summary>
+        /// <param name="field">The original <see cref="FieldProvider"/>.</param>
+        /// <returns>Null if it should be removed otherwise the modified version of the <see cref="FieldProvider"/>.</returns>
         protected virtual FieldProvider? Visit(FieldProvider field)
         {
             return field;

packages/http-client-csharp/generator/Microsoft.Generator.CSharp/src/Writers/CSharpProjectWriter.cs

@@ -10,6 +10,8 @@ namespace Microsoft.Generator.CSharp;
 
 public class CSharpProjectWriter
 {
+    private const char NewLine = '\n';
+
     public CSharpProjectWriter()
     {
         ProjectReferences = new List<CSProjDependencyPackage>();
@@ -64,7 +66,9 @@ public string Write()
         using var writer = XmlWriter.Create(builder, new XmlWriterSettings
         {
             OmitXmlDeclaration = true,
-            Indent = true
+            Indent = true,
+            NewLineChars = "\n",
+            NewLineHandling = NewLineHandling.Replace
         });
         writer.WriteStartDocument();
         // write the Project element
@@ -79,7 +83,7 @@ public string Write()
             // this is the only way I know to write a blank line in an xml document using APIs instead of just write raw strings
             // feel free to change this if other elegant way is found.
             writer.Flush();
-            builder.AppendLine();
+            builder.Append(NewLine);
             writer.WriteStartElement("ItemGroup");
             foreach (var compileInclude in CompileIncludes)
             {
@@ -92,7 +96,7 @@ public string Write()
         if (ProjectReferences.Count > 0)
         {
             writer.Flush();
-            builder.AppendLine();
+            builder.Append(NewLine);
             writer.WriteStartElement("ItemGroup");
             foreach (var package in ProjectReferences)
             {
@@ -105,7 +109,7 @@ public string Write()
         if (PackageReferences.Count > 0)
         {
             writer.Flush();
-            builder.AppendLine();
+            builder.Append(NewLine);
             writer.WriteStartElement("ItemGroup");
             foreach (var package in PackageReferences)
             {
@@ -118,7 +122,7 @@ public string Write()
         if (PrivatePackageReferences.Count > 0)
         {
             writer.Flush();
-            builder.AppendLine();
+            builder.Append(NewLine);
             writer.WriteStartElement("ItemGroup");
             foreach (var package in PrivatePackageReferences)
             {
@@ -132,7 +136,7 @@ public string Write()
         writer.Flush();
 
         // add an empty on the end of file
-        builder.AppendLine();
+        builder.Append(NewLine);
 
         return builder.ToString();
     }