Added a UniqueDocumentNameManager.cs file

Author: Taritsyn

src/MsieJavaScriptEngine/Utilities/UniqueDocumentNameManager.cs

@@ -0,0 +1,64 @@
+using System.Collections.Generic;
+using System.IO;
+
+namespace MsieJavaScriptEngine.Utilities
+{
+	/// <summary>
+	/// Unique document name manager
+	/// </summary>
+	internal sealed class UniqueDocumentNameManager
+	{
+		/// <summary>
+		/// Default document name
+		/// </summary>
+		private readonly string _defaultName;
+
+		/// <summary>
+		/// Storage of unique names
+		/// </summary>
+		private readonly Dictionary<string, uint> _storage = new Dictionary<string, uint>();
+
+		/// <summary>
+		/// Synchronizer of unique name storage
+		/// </summary>
+		private readonly object _storageSynchronizer = new object();
+
+
+		/// <summary>
+		/// Constructs an instance of the unique document name manager
+		/// </summary>
+		/// <param name="defaultName">Default document name</param>
+		public UniqueDocumentNameManager(string defaultName)
+		{
+			_defaultName = defaultName;
+		}
+
+
+		/// <summary>
+		/// Gets a unique document name
+		/// </summary>
+		/// <param name="name">Document name</param>
+		/// <returns>Unique document name</returns>
+		public string GetUniqueName(string name)
+		{
+			string appropriateName = !string.IsNullOrWhiteSpace(name) ?
+				Path.GetFileNameWithoutExtension(name) : _defaultName;
+			string extension = Path.GetExtension(name);
+
+			lock (_storageSynchronizer)
+			{
+				uint count;
+				_storage.TryGetValue(appropriateName, out count);
+				_storage[appropriateName] = ++count;
+
+				string uniqueName = count > 1 ?
+					string.Concat(appropriateName, " [", count, "]", extension)
+					:
+					string.Concat(appropriateName, extension)
+					;
+
+				return uniqueName;
+			}
+		}
+	}
+}