Clean up and add XML documentations for public methods

Author: MaggieKimani1

src/Microsoft.OpenApi.Tool/OpenApiService.cs

@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license.
+
+using System;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -24,9 +27,13 @@ public static void ProcessOpenApiDocument(
             bool inline,
             bool resolveExternal)
         {
-            if (input == null)
+            if (string.IsNullOrEmpty(input))
             {
-                throw new ArgumentNullException("input");
+                throw new ArgumentNullException(nameof(input));
+            }
+            if (output.Exists)
+            {
+                throw new IOException("The file you're writing to already exists. Please input a new output path.");
             }
 
             var stream = GetStream(input);
@@ -51,7 +58,7 @@ public static void ProcessOpenApiDocument(
 
             var context = result.OpenApiDiagnostic;
 
-            if (context.Errors.Count != 0)
+            if (context.Errors.Count > 0)
             {
                 var errorReport = new StringBuilder();
 
@@ -63,11 +70,6 @@ public static void ProcessOpenApiDocument(
                 throw new ArgumentException(string.Join(Environment.NewLine, context.Errors.Select(e => e.Message).ToArray()));
             }
 
-            if (output.Exists)
-            {
-                throw new IOException("The file you're writing to already exists.Please input a new output path.");
-            }
-
             using var outputStream = output?.Create();
 
             var textWriter = outputStream != null ? new StreamWriter(outputStream) : Console.Out;

src/Microsoft.OpenApi/Services/CopyReferences.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
 using System.Collections.Generic;
@@ -9,14 +9,18 @@ namespace Microsoft.OpenApi.Services
 {
     internal class CopyReferences : OpenApiVisitorBase
     {
-        private readonly OpenApiDocument target;
-        public OpenApiComponents Components = new OpenApiComponents();
+        private readonly OpenApiDocument _target;
+        public OpenApiComponents Components = new();
 
         public CopyReferences(OpenApiDocument target)
         {
-            this.target = target;
+            _target = target;
         }
 
+        /// <summary>
+        /// Visits IOpenApiReferenceable instances that are references and not in components.
+        /// </summary>
+        /// <param name="referenceable"> An IOpenApiReferenceable object.</param>
         public override void Visit(IOpenApiReferenceable referenceable)
         {
             switch (referenceable)
@@ -54,6 +58,10 @@ public override void Visit(IOpenApiReferenceable referenceable)
             base.Visit(referenceable);
         }
 
+        /// <summary>
+        /// Visits <see cref="OpenApiSchema"/>
+        /// </summary>
+        /// <param name="schema">The OpenApiSchema to be visited.</param>
         public override void Visit(OpenApiSchema schema)
         {
             // This is needed to handle schemas used in Responses in components
@@ -71,33 +79,33 @@ public override void Visit(OpenApiSchema schema)
 
         private void EnsureComponentsExists()
         {
-            if (target.Components == null)
+            if (_target.Components == null)
             {
-                target.Components = new OpenApiComponents();
+                _target.Components = new OpenApiComponents();
             }
         }
 
         private void EnsureSchemasExists()
         {
-            if (target.Components.Schemas == null)
+            if (_target.Components.Schemas == null)
             {
-                target.Components.Schemas = new Dictionary<string, OpenApiSchema>();
+                _target.Components.Schemas = new Dictionary<string, OpenApiSchema>();
             }
         }
 
         private void EnsureParametersExists()
         {
-            if (target.Components.Parameters == null)
+            if (_target.Components.Parameters == null)
             {
-                target.Components.Parameters = new Dictionary<string, OpenApiParameter>();
+                _target.Components.Parameters = new Dictionary<string, OpenApiParameter>();
             }
         }
 
         private void EnsureResponsesExists()
         {
-            if (target.Components.Responses == null)
+            if (_target.Components.Responses == null)
             {
-                target.Components.Responses = new Dictionary<string, OpenApiResponse>();
+                _target.Components.Responses = new Dictionary<string, OpenApiResponse>();
             }
         }
     }

src/Microsoft.OpenApi/Services/OpenApiFilterService.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
 using System;
@@ -20,8 +20,6 @@ public static class OpenApiFilterService
         /// <returns>A predicate.</returns>
         public static Func<OpenApiOperation, bool> CreatePredicate(string operationIds)
         {
-            string predicateSource = null;
-
             Func<OpenApiOperation, bool> predicate;
             if (operationIds != null)
             {
@@ -34,8 +32,6 @@ public static Func<OpenApiOperation, bool> CreatePredicate(string operationIds)
                     var operationIdsArray = operationIds.Split(',');
                     predicate = (o) => operationIdsArray.Contains(o.OperationId);
                 }
-
-                predicateSource = $"operationIds: {operationIds}";
             }
 
             else