Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Activities/System/Activities/XamlIntegration/NamespaceTable.cs

@@ -0,0 +1,119 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.Activities.XamlIntegration
+{
+    using System.Collections.Generic;
+    using System.Xaml;
+
+    class NamespaceTable : IXamlNamespaceResolver
+    {
+        List<NamespaceDeclaration> tempNamespaceList;
+        Stack<List<NamespaceDeclaration>> namespaceStack;
+        Dictionary<string, NamespaceDeclaration> namespacesCache;
+
+        public NamespaceTable()
+        {
+            this.tempNamespaceList = new List<NamespaceDeclaration>();
+            this.namespaceStack = new Stack<List<NamespaceDeclaration>>();
+        }
+
+        public string GetNamespace(string prefix)
+        {
+            NamespaceDeclaration result;
+            if (this.namespacesCache == null)
+            {
+                ConstructNamespaceCache();
+            }
+
+            if (this.namespacesCache.TryGetValue(prefix, out result))
+            {
+                return result.Namespace;
+            }
+            else
+            {
+                return null;
+            }
+        }
+
+        public void ManageNamespace(XamlReader reader)
+        {
+            switch (reader.NodeType)
+            {
+                case XamlNodeType.NamespaceDeclaration:
+                    AddNamespace(reader.Namespace);
+                    break;
+                case XamlNodeType.StartObject:
+                case XamlNodeType.StartMember:
+                case XamlNodeType.GetObject:
+                    EnterScope();
+                    break;
+                case XamlNodeType.EndMember:
+                case XamlNodeType.EndObject:
+                    ExitScope();
+                    break;
+            }
+        }
+
+        public void AddNamespace(NamespaceDeclaration xamlNamespace)
+        {
+            this.tempNamespaceList.Add(xamlNamespace);
+            this.namespacesCache = null;
+        }
+
+        public void EnterScope()
+        {
+            if (this.tempNamespaceList != null)
+            {
+                this.namespaceStack.Push(this.tempNamespaceList);
+                this.tempNamespaceList = new List<NamespaceDeclaration>();
+            }
+        }
+
+        public void ExitScope()
+        {
+            List<NamespaceDeclaration> namespaceList = this.namespaceStack.Pop();
+            if (namespaceList.Count != 0)
+            {
+                this.namespacesCache = null;
+            }
+        }
+
+        public IEnumerable<NamespaceDeclaration> GetNamespacePrefixes()
+        {
+            if (this.namespacesCache == null)
+            {
+                ConstructNamespaceCache();
+            }
+
+            return this.namespacesCache.Values;
+        }
+
+        void ConstructNamespaceCache()
+        {
+            Dictionary<string, NamespaceDeclaration> localNamespaces = new Dictionary<string, NamespaceDeclaration>();
+            if (this.tempNamespaceList != null && this.tempNamespaceList.Count > 0)
+            {
+                foreach (NamespaceDeclaration tempNamespace in tempNamespaceList)
+                {
+                    if (!localNamespaces.ContainsKey(tempNamespace.Prefix))
+                    {
+                        localNamespaces.Add(tempNamespace.Prefix, tempNamespace);
+                    }
+                }
+            }
+            foreach (List<NamespaceDeclaration> currentNamespaces in this.namespaceStack)
+            {
+                foreach (NamespaceDeclaration currentNamespace in currentNamespaces)
+                {
+                    if (!localNamespaces.ContainsKey(currentNamespace.Prefix))
+                    {
+                        localNamespaces.Add(currentNamespace.Prefix, currentNamespace);
+                    }
+                }
+            }
+            this.namespacesCache = localNamespaces;
+        }
+    }
+}