Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/ModelBinding/NameValueCollectionValueProvider.cs

@@ -0,0 +1,95 @@
+namespace System.Web.ModelBinding {
+    using System;
+    using System.Collections.Generic;
+    using System.Collections.Specialized;
+    using System.Globalization;
+    using System.Linq;
+    using System.Threading;
+
+    public class NameValueCollectionValueProvider : IValueProvider, IUnvalidatedValueProvider {
+
+        private readonly CultureInfo _culture;
+        private readonly PrefixContainer _prefixes;
+        private readonly Dictionary<string, ValueProviderResultPlaceholder> _values = new Dictionary<string, ValueProviderResultPlaceholder>(StringComparer.OrdinalIgnoreCase);
+        private readonly NameValueCollection _validatedCollection;
+        private readonly NameValueCollection _unvalidatedCollection;
+
+        public NameValueCollectionValueProvider(NameValueCollection collection, CultureInfo culture)
+            : this(collection, null /* unvalidatedCollection */, culture) {
+        }
+
+        public NameValueCollectionValueProvider(NameValueCollection collection, NameValueCollection unvalidatedCollection, CultureInfo culture) {
+            if (collection == null) {
+                throw new ArgumentNullException("collection");
+            }
+
+            _culture = culture;
+            _prefixes = new PrefixContainer(collection.Keys.Cast<string>());
+            _validatedCollection = collection;
+            _unvalidatedCollection = unvalidatedCollection ?? collection;
+
+            foreach (string key in collection) {
+                if (key != null) {
+                    _values[key] = new ValueProviderResultPlaceholder(key, this);
+                }
+            }
+        }
+
+        public virtual bool ContainsPrefix(string prefix) {
+            if (prefix == null) {
+                throw new ArgumentNullException("prefix");
+            }
+
+            return _prefixes.ContainsPrefix(prefix);
+        }
+
+        public virtual ValueProviderResult GetValue(string key) {
+            return GetValue(key, skipValidation: false);
+        }
+
+        public virtual ValueProviderResult GetValue(string key, bool skipValidation) {
+            if (key == null) {
+                throw new ArgumentNullException("key");
+            }
+
+            ValueProviderResultPlaceholder placeholder;
+            _values.TryGetValue(key, out placeholder);
+            if (placeholder == null) {
+                return null;
+            }
+            else {
+                return (skipValidation) ? placeholder.UnvalidatedResult : placeholder.ValidatedResult;
+            }
+        }
+
+        // Placeholder that can store a validated (in relation to request validation) or unvalidated
+        // ValueProviderResult for a given key.
+        private sealed class ValueProviderResultPlaceholder {
+            private readonly Func<ValueProviderResult> _validatedResultAccessor;
+            private readonly Func<ValueProviderResult> _unvalidatedResultAccessor;
+            private ValueProviderResult _validatedResult;
+            private ValueProviderResult _unvalidatedResult;
+
+            public ValueProviderResultPlaceholder(string key, NameValueCollectionValueProvider valueProvider) {
+                _validatedResultAccessor = () => GetResultFromCollection(key, valueProvider, useValidatedCollection: true);
+                _unvalidatedResultAccessor = () => GetResultFromCollection(key, valueProvider, useValidatedCollection: false);
+            }
+
+            private static ValueProviderResult GetResultFromCollection(string key, NameValueCollectionValueProvider valueProvider, bool useValidatedCollection) {
+                NameValueCollection collection = (useValidatedCollection) ? valueProvider._validatedCollection : valueProvider._unvalidatedCollection;
+                string[] rawValue = collection.GetValues(key);
+                string attemptedValue = collection[key];
+                return new ValueProviderResult(rawValue, attemptedValue, valueProvider._culture);
+            }
+
+            public ValueProviderResult ValidatedResult {
+                get { return LazyInitializer.EnsureInitialized(ref _validatedResult, _validatedResultAccessor); }
+            }
+
+            public ValueProviderResult UnvalidatedResult {
+                get { return LazyInitializer.EnsureInitialized(ref _unvalidatedResult, _unvalidatedResultAccessor); }
+            }
+        }
+
+    }
+}