Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Data.Entity/System/Data/Metadata/Edm/MetadataPropertyCollection.cs

@@ -0,0 +1,133 @@
+//---------------------------------------------------------------------
+// <copyright file="MetadataPropertyCollection.cs" company="Microsoft">
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//
+// @owner       [....]
+// @backupOwner [....]
+//---------------------------------------------------------------------
+
+using System;
+using System.Collections.Generic;
+using System.Data.Common;
+using System.Diagnostics;
+using System.Reflection;
+using System.Data.Common.Utils;
+
+namespace System.Data.Metadata.Edm
+{
+    /// <summary>
+    /// Metadata collection class supporting delay-loading of system item attributes and
+    /// extended attributes.
+    /// </summary>
+    internal sealed class MetadataPropertyCollection : MetadataCollection<MetadataProperty>
+    {
+        /// <summary>
+        /// Constructor taking item.
+        /// </summary>
+        /// <param name="item">Item with which the collection is associated.</param>
+        internal MetadataPropertyCollection(MetadataItem item)
+            : base(GetSystemMetadataProperties(item))
+        {
+        }
+
+        private readonly static Memoizer<Type, ItemTypeInformation> s_itemTypeMemoizer =
+            new Memoizer<Type, ItemTypeInformation>(clrType => new ItemTypeInformation(clrType), null);
+
+        // Given an item, returns all system type attributes for the item.
+        private static IEnumerable<MetadataProperty> GetSystemMetadataProperties(MetadataItem item)
+        {
+            EntityUtil.CheckArgumentNull(item, "item");
+            Type type = item.GetType();
+            ItemTypeInformation itemTypeInformation = GetItemTypeInformation(type);
+            return itemTypeInformation.GetItemAttributes(item);
+        }
+
+        // Retrieves metadata for type.
+        private static ItemTypeInformation GetItemTypeInformation(Type clrType)
+        {
+            return s_itemTypeMemoizer.Evaluate(clrType);
+        }
+
+        /// <summary>
+        /// Encapsulates information about system item attributes for a particular item type.
+        /// </summary>
+        private class ItemTypeInformation
+        {
+            /// <summary>
+            /// Retrieves system attribute information for the given type.
+            /// Requires: type must derive from MetadataItem
+            /// </summary>
+            /// <param name="clrType">Type</param>
+            internal ItemTypeInformation(Type clrType)
+            {
+                Debug.Assert(null != clrType);
+
+                _itemProperties = GetItemProperties(clrType);
+            }
+
+            private readonly List<ItemPropertyInfo> _itemProperties;
+
+            // Returns system item attributes for the given item.
+            internal IEnumerable<MetadataProperty> GetItemAttributes(MetadataItem item)
+            {
+                foreach (ItemPropertyInfo propertyInfo in _itemProperties)
+                {
+                    yield return propertyInfo.GetMetadataProperty(item);
+                }
+            }
+
+            // Gets type information for item with the given type. Uses cached information where 
+            // available.
+            private static List<ItemPropertyInfo> GetItemProperties(Type clrType)
+            {
+                List<ItemPropertyInfo> result = new List<ItemPropertyInfo>();
+                foreach (PropertyInfo propertyInfo in clrType.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic))
+                {
+                    foreach (MetadataPropertyAttribute attribute in propertyInfo.GetCustomAttributes(
+                        typeof(MetadataPropertyAttribute), false))
+                    {
+                        result.Add(new ItemPropertyInfo(propertyInfo, attribute));
+                    }
+                }
+                return result;
+            }
+        }
+
+
+        /// <summary>
+        /// Encapsulates information about a CLR property of an item class.
+        /// </summary>
+        private class ItemPropertyInfo
+        {
+            /// <summary>
+            /// Initialize information.
+            /// Requires: attribute must belong to the given property.
+            /// </summary>
+            /// <param name="propertyInfo">Property referenced.</param>
+            /// <param name="attribute">Attribute for the property.</param>
+            internal ItemPropertyInfo(PropertyInfo propertyInfo, MetadataPropertyAttribute attribute)
+            {
+                Debug.Assert(null != propertyInfo);
+                Debug.Assert(null != attribute);
+
+                _propertyInfo = propertyInfo;
+                _attribute = attribute;
+            }
+
+            private readonly MetadataPropertyAttribute _attribute;
+            private readonly PropertyInfo _propertyInfo;
+
+            /// <summary>
+            /// Given an item, returns an instance of the item attribute described by this class.
+            /// </summary>
+            /// <param name="item">Item from which to retrieve attribute.</param>
+            /// <returns>Item attribute.</returns>
+            internal MetadataProperty GetMetadataProperty(MetadataItem item)
+            {
+                return new MetadataProperty(_propertyInfo.Name, _attribute.Type, _attribute.IsCollectionType,
+                    new MetadataPropertyValue(_propertyInfo, item));
+            }
+        }
+    }
+}