Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/class/System.Web.Mvc3/Mvc/ValueProviderUtil.cs

@@ -0,0 +1,51 @@
+namespace System.Web.Mvc {
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+
+    internal static class ValueProviderUtil {
+
+        // Given "foo.bar[baz].quux", this method will return:
+        // - "foo.bar[baz].quux"
+        // - "foo.bar[baz]"
+        // - "foo.bar"
+        // - "foo"
+        public static IEnumerable<string> GetPrefixes(string key) {
+            yield return key;
+            for (int i = key.Length - 1; i >= 0; i--) {
+                switch (key[i]) {
+                    case '.':
+                    case '[':
+                        yield return key.Substring(0, i);
+                        break;
+                }
+            }
+        }
+
+        public static bool CollectionContainsPrefix(IEnumerable<string> collection, string prefix) {
+            foreach (string key in collection) {
+                if (key != null) {
+                    if (prefix.Length == 0) {
+                        return true; // shortcut - non-null key matches empty prefix
+                    }
+
+                    if (key.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)) {
+                        if (key.Length == prefix.Length) {
+                            return true; // exact match
+                        }
+                        else {
+                            switch (key[prefix.Length]) {
+                                case '.': // known separator characters
+                                case '[':
+                                    return true;
+                            }
+                        }
+                    }
+                }
+            }
+
+            return false; // nothing found
+        }
+
+    }
+}