Add ProjectOperationBenchmarks

Related to dotnet#48682

src/Tools/IdeCoreBenchmarks/ProjectOperationBenchmarks.cs

@@ -0,0 +1,102 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Text;
+using BenchmarkDotNet.Attributes;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.Text;
+
+namespace IdeCoreBenchmarks
+{
+    public class ProjectOperationBenchmarks
+    {
+        [MemoryDiagnoser]
+        public class IterateDocuments
+        {
+            private Workspace _workspace;
+            private Project _emptyProject;
+            private Project _hundredProject;
+            private Project _thousandsProject;
+
+            public IterateDocuments()
+            {
+                // These fields are initialized in GlobalSetup
+                _workspace = null!;
+                _emptyProject = null!;
+                _hundredProject = null!;
+                _thousandsProject = null!;
+            }
+
+            [Params(0, 100, 10000)]
+            public int DocumentCount { get; set; }
+
+            private Project Project
+            {
+                get
+                {
+                    return DocumentCount switch
+                    {
+                        0 => _emptyProject,
+                        100 => _hundredProject,
+                        10000 => _thousandsProject,
+                        _ => throw new NotSupportedException($"'{nameof(DocumentCount)}' is out of range"),
+                    };
+                }
+            }
+
+            [GlobalSetup]
+            public void GlobalSetup()
+            {
+                _workspace = new AdhocWorkspace();
+
+                var solution = _workspace.CurrentSolution;
+                _emptyProject = CreateProject(ref solution, name: "A", documentCount: 0);
+                _hundredProject = CreateProject(ref solution, name: "A", documentCount: 100);
+                _thousandsProject = CreateProject(ref solution, name: "A", documentCount: 10000);
+
+                static Project CreateProject(ref Solution solution, string name, int documentCount)
+                {
+                    var projectId = ProjectId.CreateNewId(name);
+                    solution = solution.AddProject(projectId, name, name, LanguageNames.CSharp);
+
+                    var emptySourceText = SourceText.From("", Encoding.UTF8);
+                    for (var i = 0; i < documentCount; i++)
+                    {
+                        var documentName = $"{i}.cs";
+                        var documentId = DocumentId.CreateNewId(projectId, documentName);
+                        solution = solution.AddDocument(documentId, documentName, emptySourceText);
+                    }
+
+                    return solution.GetRequiredProject(projectId);
+                }
+            }
+
+            [Benchmark(Description = "Project.DocumentIds")]
+            public int DocumentIds()
+            {
+                var count = 0;
+                foreach (var _ in Project.DocumentIds)
+                {
+                    count++;
+                }
+
+                return count;
+            }
+
+            [Benchmark(Description = "Project.Documents")]
+            public int Documents()
+            {
+                var count = 0;
+                foreach (var _ in Project.Documents)
+                {
+                    count++;
+                }
+
+                return count;
+            }
+        }
+    }
+}