roslyn-string-vs-stream-sourcetext.linq

<Query Kind="Program">
  <NuGetReference>Microsoft.AspNet.Mvc</NuGetReference>
  <NuGetReference>Microsoft.CodeAnalysis.CSharp</NuGetReference>
  <Namespace>System.CodeDom.Compiler</Namespace>
  <Namespace>System.Web.Razor</Namespace>
  <Namespace>System.Web.WebPages.Razor</Namespace>
  <Namespace>Microsoft.CodeAnalysis</Namespace>
  <Namespace>Microsoft.CodeAnalysis.CSharp</Namespace>
  <Namespace>Microsoft.CodeAnalysis.Emit</Namespace>
  <Namespace>Microsoft.CodeAnalysis.Text</Namespace>
</Query>

void Main()
{
	var counts = new int[] { 5, 1000, 10000, 25000, 50000 };
	var host = WebRazorHostFactory.CreateDefaultHost("test.chstml", "test.cshtml");
	var references = AppDomain.CurrentDomain
		.GetAssemblies()
		.Where(a => !a.IsDynamic && !string.IsNullOrWhiteSpace(a.Location))
		.Select(x => (MetadataReference)MetadataReference.CreateFromFile(x.Location, MetadataReferenceProperties.Assembly))
		.ToArray();

	foreach (var count in counts)
	{
		var source = string.Join(Environment.NewLine, Enumerable.Repeat("<p>@DateTime.Now</p>", count));

		using (var rdr = new StringReader(source))
		using (var provider = CodeDomProvider.CreateProvider("csharp"))
		using (var generatedString = new StringWriter())
		using (var generatedStream = new MemoryStream())
		using (var generatedWriter = new StreamWriter(generatedStream))
		{
			var engine = new RazorTemplateEngine(host);
			var razorOut = engine.GenerateCode(rdr, null, null, "test.cshtml");
			var codeGenOptions = new CodeGeneratorOptions { VerbatimOrder = true, ElseOnClosing = false, BlankLinesBetweenMembers = false };
			provider.GenerateCodeFromCompileUnit(razorOut.GeneratedCode, generatedWriter, codeGenOptions);
			provider.GenerateCodeFromCompileUnit(razorOut.GeneratedCode, generatedString, codeGenOptions);

			// rewind
			generatedWriter.Flush();
			generatedStream.Position = 0;

			generatedString.Flush();
			var cases = new Dictionary<string, SourceText>
			{
				{ "stream", SourceText.From(generatedStream, Encoding.UTF8) },
				{ "string", SourceText.From(generatedString.GetStringBuilder().ToString(), Encoding.UTF8) },
			};
			
			// if (count == 5) Console.WriteLine(cases["string"].ToString());
			
			foreach (var c in cases) 
			{
				var name = $"test.{c.Key}.{count}.dll";
				var args = CSharpCommandLineParser.Default.Parse(
					$"/subsystemversion:6.00 /target:library /utf8output /noconfig /nowarn:1701,1702,2008 /nostdlib+ /platform:anycpu /errorreport:prompt /warn:4 /define:DEBUG;TRACE /errorendlocation /preferreduilang:en-US /highentropyva+ /out:{name}"
					.Split(' '), ".", null);
				var sw = Stopwatch.StartNew();
				var compilation = CSharpCompilation.Create(
						options: args.CompilationOptions.WithAssemblyIdentityComparer(DesktopAssemblyIdentityComparer.Default),
						references: references,
						syntaxTrees: new[] {
							SyntaxFactory.ParseSyntaxTree(c.Value, path: $"test.{c.Key}.{count}.cshtml"),
						},
						assemblyName: name);

				var t1 = sw.ElapsedMilliseconds;
				sw.Restart();
				using (var peStream = new MemoryStream(10000000))
				using (var pdbStream = new MemoryStream(10000000))
				using (var win32Resources = compilation.CreateDefaultWin32Resources(
					versionResource: true,
					noManifest: true,
					manifestContents: null,
					iconInIcoFormat: null))
				{
					var emitResult = compilation.Emit(
						peStream: peStream,
						pdbStream: pdbStream,
						options: args.EmitOptions,
						xmlDocumentationStream: null,
						win32Resources: win32Resources);
					if (!emitResult.Success)
						foreach (var d in emitResult.Diagnostics)
							Console.WriteLine(d);

				}
				sw.Stop();

				Console.WriteLine($"{count,10} {c.Key,10} {t1,7}ms {sw.ElapsedMilliseconds,7}ms");
			}
		}
	}
}

Output

         5     stream       0ms      21ms
         5     string       0ms       8ms
      1000     stream      15ms     115ms
      1000     string      15ms      88ms
     10000     stream     165ms     789ms
     10000     string     171ms     773ms
     25000     stream     424ms    2149ms
     25000     string     604ms    2137ms
     50000     stream     834ms    4321ms
     50000     string    1057ms    4242ms