chore: import upstream snapshot with attribution

2026-07-13 13:02:50 +08:00
commit 0fc60fdcb1
5008 changed files with 910633 additions and 0 deletions
@@ -0,0 +1,84 @@
+/*
+ * QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
+ * Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); 
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+*/
+using System.IO;
+
+namespace QuantConnect.ToolBox
+{
+    /// <summary>
+    /// This class wraps a <see cref="StreamWriter"/> so that the StreamWriter is only
+    /// instantiated until WriteLine() is called.  This ensures that the file the StreamWriter is
+    /// writing to is only created if something is written to it. A StreamWriter will create a empty file
+    /// as soon as it is instantiated.
+    /// </summary>
+    public class LazyStreamWriter
+    {
+        private StreamWriter _streamWriter;
+        private readonly string _path;
+
+        /// <summary>
+        /// Constructor for the <see cref="LazyStreamWriter"/>
+        /// </summary>
+        /// <param name="path">Path to the file that should be created</param>
+        public LazyStreamWriter(string path)
+        {
+            _path = path;
+        }
+
+        /// <summary>
+        /// Wraps the WriteLine method of the StreamWriter.
+        /// </summary>
+        /// <param name="line">The line to write</param>
+        /// <remarks>Will instantiate the StreamWriter if this is the first time this method is called</remarks>
+        public void WriteLine(string line)
+        {
+            PrepareStreamWriter();
+
+            _streamWriter.WriteLine(line);
+        }
+
+        /// <summary>
+        /// Wraps the <see cref="StreamWriter.Flush()"/> method
+        /// </summary>
+        public void Flush()
+        {
+            if (_streamWriter != null)
+            {
+                _streamWriter.Flush();
+            }
+        }
+
+        /// <summary>
+        /// Wraps the <see cref="StreamWriter.Close()"/> method
+        /// </summary>
+        public void Close()
+        {
+            if (_streamWriter != null)
+            {
+                _streamWriter.Close();
+            }
+        }
+
+        /// <summary>
+        /// Checks if the StreamWriter is instantiated. If not, it will instantiate the StreamWriter
+        /// </summary>
+        private void PrepareStreamWriter()
+        {
+            if (_streamWriter == null)
+            {
+                _streamWriter = new StreamWriter(_path);
+            }
+        }
+    }
+}