From a8a49bc75cac93d6784334281810e6e8dcf6531a Mon Sep 17 00:00:00 2001
From: Michael Becker <alcexhim@gmail.com>
Date: Sat, 6 Aug 2022 18:57:02 -0400
Subject: [PATCH] improve new line detection and handling

---
 .../IO/NewLineSequence.cs                     | 12 ++++
 Libraries/UniversalEditor.Core/IO/Reader.cs   | 65 ++++++++++++++++---
 .../IO/ReaderWriterBase.cs                    | 18 +++--
 3 files changed, 81 insertions(+), 14 deletions(-)

diff --git a/Libraries/UniversalEditor.Core/IO/NewLineSequence.cs b/Libraries/UniversalEditor.Core/IO/NewLineSequence.cs
index 4d79a621..dbc7cb3b 100644
--- a/Libraries/UniversalEditor.Core/IO/NewLineSequence.cs
+++ b/Libraries/UniversalEditor.Core/IO/NewLineSequence.cs
@@ -23,6 +23,18 @@ namespace UniversalEditor.IO
 {
 	public enum NewLineSequence
 	{
+		/// <summary>
+		/// Determines the new line sequence based on whether there is a '\r' or a
+		/// '\n', or both, at the end of a line.
+		/// </summary>
+		/// <remarks>
+		/// DO NOT USE ON BINARY FILES OR OVER NETWORK STREAMS. The detection
+		/// logic requires a line to end eventually with a '\r' or a '\n'
+		/// character. universal editor will keep reading until it encounters one
+		/// of those characters, or hits the end of the file. on a network stream,
+		/// this may never happen, and your program may end up waiting forever.
+		/// </remarks>
+		Automatic = -2,
 		/// <summary>
 		/// Determines the new line sequence based on the system default (CR on Mac OS up to version 9, LF on Linux,
 		/// CRLF on Windows).
diff --git a/Libraries/UniversalEditor.Core/IO/Reader.cs b/Libraries/UniversalEditor.Core/IO/Reader.cs
index 42ba6eab..9eb19e76 100644
--- a/Libraries/UniversalEditor.Core/IO/Reader.cs
+++ b/Libraries/UniversalEditor.Core/IO/Reader.cs
@@ -1075,11 +1075,7 @@ namespace UniversalEditor.IO
 			return encoding.GetString(data);
 		}
 
-		public byte[] ReadUntil(byte[] sequence)
-		{
-			return ReadUntil(sequence, false);
-		}
-		public byte[] ReadUntil(byte[] sequence, bool includeSequence)
+		public byte[] ReadUntil(byte[] sequence, bool includeSequence = false)
 		{
 			byte[] w = new byte[0];
 			while (!EndOfStream)
@@ -1107,6 +1103,8 @@ namespace UniversalEditor.IO
 					if (!includeSequence)
 					{
 						Array.Resize(ref w, w.Length - sequence.Length);
+
+						// HACK: we aren't including the sequence in the response, BUT we should consume it anyway... right?
 						try
 						{
 							Seek(-sequence.Length, SeekOrigin.Current);
@@ -1115,6 +1113,7 @@ namespace UniversalEditor.IO
 						{
 
 						}
+
 					}
 					return w;
 				}
@@ -1785,11 +1784,57 @@ namespace UniversalEditor.IO
 		public string ReadLine()
 		{
 			StringBuilder sb = new StringBuilder();
-			string line = ReadUntil(GetNewLineSequence());
-			// ReadChars(GetNewLineSequence().Length);
-			if (line.EndsWith("\r"))
-				line = line.Substring(0, line.Length - 1);
-			return line;
+			if (NewLineSequence == NewLineSequence.Automatic && _ActualNewLineSequenceForAutomatic == NewLineSequence.Default)
+			{
+				// first time around, determine actual new line sequence
+				while (!EndOfStream)
+				{
+					char c = ReadChar();
+					if (c == '\n')
+					{
+						char c2 = PeekChar();
+						if (c2 == '\r')
+						{
+							ReadChar();
+							_ActualNewLineSequenceForAutomatic = NewLineSequence.LineFeedCarriageReturn;
+							break;
+						}
+						else
+						{
+							_ActualNewLineSequenceForAutomatic = NewLineSequence.LineFeed;
+							break;
+						}
+					}
+					else if (c == '\r')
+					{
+						char c2 = PeekChar();
+						if (c2 == '\n')
+						{
+							ReadChar();
+							_ActualNewLineSequenceForAutomatic = NewLineSequence.CarriageReturnLineFeed;
+							break;
+						}
+						else
+						{
+							_ActualNewLineSequenceForAutomatic = NewLineSequence.CarriageReturn;
+							break;
+						}
+					}
+					else
+					{
+						sb.Append(c);
+					}
+				}
+				return sb.ToString();
+			}
+			else
+			{
+				string line = ReadUntil(GetNewLineSequence());
+				ReadChars(GetNewLineSequence().Length);
+				if (line.EndsWith("\r"))
+					line = line.Substring(0, line.Length - 1);
+				return line;
+			}
 		}
 
 		/// <summary>
diff --git a/Libraries/UniversalEditor.Core/IO/ReaderWriterBase.cs b/Libraries/UniversalEditor.Core/IO/ReaderWriterBase.cs
index d3492a83..c846e477 100644
--- a/Libraries/UniversalEditor.Core/IO/ReaderWriterBase.cs
+++ b/Libraries/UniversalEditor.Core/IO/ReaderWriterBase.cs
@@ -46,12 +46,18 @@ namespace UniversalEditor.IO
 
 		public Transformation.TransformationCollection Transformations { get; } = new Transformation.TransformationCollection();
 
-		private NewLineSequence mvarNewLineSequence = NewLineSequence.Default;
-		public NewLineSequence NewLineSequence { get { return mvarNewLineSequence; } set { mvarNewLineSequence = value; } }
-		public string GetNewLineSequence()
+		protected NewLineSequence _ActualNewLineSequenceForAutomatic = NewLineSequence.Default;
+		public NewLineSequence NewLineSequence { get; set; } = NewLineSequence.Automatic;
+
+		private string GetNewLineSequence(NewLineSequence newLineSequence)
 		{
+			if (newLineSequence == NewLineSequence.Automatic)
+			{
+				return GetNewLineSequence(_ActualNewLineSequenceForAutomatic);
+			}
+
 			string newline = System.Environment.NewLine;
-			switch (mvarNewLineSequence)
+			switch (newLineSequence)
 			{
 				case IO.NewLineSequence.CarriageReturn:
 				{
@@ -76,6 +82,10 @@ namespace UniversalEditor.IO
 			}
 			return newline;
 		}
+		public string GetNewLineSequence()
+		{
+			return GetNewLineSequence(NewLineSequence);
+		}
 
 		public ReaderWriterBase(Accessor accessor)
 		{