System.Xml.Xsl.IlGen.IteratorDescriptor.EnsureItemStorageType C# (CSharp) Method

        public void EnsureItemStorageType(XmlQueryType xmlType, Type storageTypeDest) {
            // If source type = destination type, then done
            if (this.storage.ItemStorageType == storageTypeDest)
                goto SetStorageType;

            Debug.Assert(this.storage.ItemStorageType == typeof(XPathItem) || storageTypeDest == typeof(XPathItem),
                         "EnsureItemStorageType must convert to or from Item");

            // If items are cached,
            if (this.storage.IsCached) {
                // Check for special case of IList<XPathNavigator> -> IList<XPathItem>
                if (this.storage.ItemStorageType == typeof(XPathNavigator)) {
                    EnsureStack();
                    this.helper.Call(XmlILMethods.NavsToItems);
                    goto SetStorageType;
                }

                // Check for special case of IList<XPathItem> -> IList<XPathNavigator>
                if (storageTypeDest == typeof(XPathNavigator)) {
                    EnsureStack();
                    this.helper.Call(XmlILMethods.ItemsToNavs);
                    goto SetStorageType;
                }
            }

            // Iterate over each item, and convert each to the destination type
            EnsureStackNoCache();

            // If source type is Item,
            if (this.storage.ItemStorageType == typeof(XPathItem)) {
                // Then downcast to Navigator
                if (storageTypeDest == typeof(XPathNavigator)) {
                    this.helper.Emit(OpCodes.Castclass, typeof(XPathNavigator));
                }
                else {
                    // Call ValueAs methods for atomic types
                    this.helper.CallValueAs(storageTypeDest);
                }
                goto SetStorageType;
            }
            else if (this.storage.ItemStorageType == typeof(XPathNavigator)) {
                // No-op if converting from XPathNavigator to XPathItem
                Debug.Assert(storageTypeDest == typeof(XPathItem), "Must be converting from XPathNavigator to XPathItem");
                goto SetStorageType;
            }

            // Destination type must be item, so generate code to create an XmlAtomicValue
            this.helper.LoadInteger(this.helper.StaticData.DeclareXmlType(xmlType));
            this.helper.LoadQueryRuntime();
            this.helper.Call(XmlILMethods.StorageMethods[this.storage.ItemStorageType].ToAtomicValue);

        SetStorageType:
            this.storage = this.storage.ToStorageType(storageTypeDest);
        }
    }