Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Data.Linq/SqlClient/Common/SqlNodeAnnotations.cs

@@ -0,0 +1,55 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace System.Data.Linq.SqlClient {
+
+    /// <summary>
+    /// Associate annotations with SqlNodes.
+    /// </summary>
+    internal class SqlNodeAnnotations {
+        Dictionary<SqlNode, List<SqlNodeAnnotation>> annotationMap = new Dictionary<SqlNode, List<SqlNodeAnnotation>>();
+        Dictionary<Type, string> uniqueTypes = new Dictionary<Type, string>();
+
+        /// <summary>
+        /// Add an annotation to the given node.
+        /// </summary>
+        internal void Add(SqlNode node, SqlNodeAnnotation annotation) {
+            List<SqlNodeAnnotation> list = null;
+            
+            if (!this.annotationMap.TryGetValue(node, out list)) {
+                list = new List<SqlNodeAnnotation>();
+                this.annotationMap[node]=list;
+            }
+
+            uniqueTypes[annotation.GetType()] = String.Empty;
+
+            list.Add(annotation);
+        }
+
+        /// <summary>
+        /// Gets the annotations for the given node. Null if none.
+        /// </summary>
+        internal List<SqlNodeAnnotation> Get(SqlNode node) {
+            List<SqlNodeAnnotation> list = null;
+            this.annotationMap.TryGetValue(node, out list);
+            return list;
+        }
+
+        /// <summary>
+        /// Whether the given node has annotations.
+        /// </summary>
+        internal bool NodeIsAnnotated(SqlNode node) {
+            if (node == null)
+                return false;
+            return this.annotationMap.ContainsKey(node);
+        }
+
+        /// <summary>
+        /// Checks whether there's at least one annotation of the given type.
+        /// </summary>
+        internal bool HasAnnotationType(Type type) {
+            return this.uniqueTypes.ContainsKey(type);
+        }
+    }
+}