Copies OpenApiOperation references to the new subset document

Author: MaggieKimani1

src/Microsoft.OpenApi/Services/CopyReferences.cs

@@ -0,0 +1,101 @@
+using System.Collections.Generic;
+using Microsoft.OpenApi.Interfaces;
+using Microsoft.OpenApi.Models;
+
+namespace Microsoft.OpenApi.Services
+{
+    internal class CopyReferences : OpenApiVisitorBase
+    {
+        private readonly OpenApiDocument target;
+        public OpenApiComponents Components = new OpenApiComponents();
+
+        public CopyReferences(OpenApiDocument target)
+        {
+            this.target = target;
+        }
+
+        public override void Visit(IOpenApiReferenceable referenceable)
+        {
+            switch (referenceable)
+            {
+                case OpenApiSchema schema:
+                    EnsureComponentsExists();
+                    EnsureSchemasExists();
+                    if (!Components.Schemas.ContainsKey(schema.Reference.Id))
+                    {
+                        Components.Schemas.Add(schema.Reference.Id, schema);
+                    }
+                    break;
+
+                case OpenApiParameter parameter:
+                    EnsureComponentsExists();
+                    EnsureParametersExists();
+                    if (!Components.Parameters.ContainsKey(parameter.Reference.Id))
+                    {
+                        Components.Parameters.Add(parameter.Reference.Id, parameter);
+                    }
+                    break;
+
+                case OpenApiResponse response:
+                    EnsureComponentsExists();
+                    EnsureResponsesExists();
+                    if (!Components.Responses.ContainsKey(response.Reference.Id))
+                    {
+                        Components.Responses.Add(response.Reference.Id, response);
+                    }
+                    break;
+
+                default:
+                    break;
+            }
+            base.Visit(referenceable);
+        }
+
+        public override void Visit(OpenApiSchema schema)
+        {
+            // This is needed to handle schemas used in Responses in components
+            if (schema.Reference != null)
+            {
+                EnsureComponentsExists();
+                EnsureSchemasExists();
+                if (!Components.Schemas.ContainsKey(schema.Reference.Id))
+                {
+                    Components.Schemas.Add(schema.Reference.Id, schema);
+                }
+            }
+            base.Visit(schema);
+        }
+
+        private void EnsureComponentsExists()
+        {
+            if (target.Components == null)
+            {
+                target.Components = new OpenApiComponents();
+            }
+        }
+
+        private void EnsureSchemasExists()
+        {
+            if (target.Components.Schemas == null)
+            {
+                target.Components.Schemas = new Dictionary<string, OpenApiSchema>();
+            }
+        }
+
+        private void EnsureParametersExists()
+        {
+            if (target.Components.Parameters == null)
+            {
+                target.Components.Parameters = new Dictionary<string, OpenApiParameter>();
+            }
+        }
+
+        private void EnsureResponsesExists()
+        {
+            if (target.Components.Responses == null)
+            {
+                target.Components.Responses = new Dictionary<string, OpenApiResponse>();
+            }
+        }
+    }
+}