Port .NET Native type name parser (dotnet#1472)

* Add type parser

* PR feedback

* Fix mono build

* Move corert code to external

* Match filepaths

external/corert/README.md

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+The code in this folder was adapted from dotnet/corert commit c8bfca5f4554badfb89b80d2319769f83512bf62

external/corert/src/System.Private.CoreLib/shared/System/Reflection/AssemblyNameFormatter.cs

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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.IO;
+using System.Text;
+using System.Globalization;
+using System.Collections.Generic;
+
+namespace System.Reflection
+{
+	internal static class AssemblyNameFormatter
+	{
+		public static string ComputeDisplayName(RuntimeAssemblyName a)
+		{
+			const int PUBLIC_KEY_TOKEN_LEN = 8;
+
+			if (a.Name == string.Empty)
+				throw new FileLoadException();
+
+			StringBuilder sb = new StringBuilder();
+			if (a.Name != null)
+			{
+				sb.AppendQuoted(a.Name);
+			}
+
+			if (a.Version != null)
+			{
+				Version canonicalizedVersion = a.Version.CanonicalizeVersion();
+				if (canonicalizedVersion.Major != ushort.MaxValue)
+				{
+					sb.Append(", Version=");
+					sb.Append(canonicalizedVersion.Major);
+
+					if (canonicalizedVersion.Minor != ushort.MaxValue)
+					{
+						sb.Append('.');
+						sb.Append(canonicalizedVersion.Minor);
+
+						if (canonicalizedVersion.Build != ushort.MaxValue)
+						{
+							sb.Append('.');
+							sb.Append(canonicalizedVersion.Build);
+
+							if (canonicalizedVersion.Revision != ushort.MaxValue)
+							{
+								sb.Append('.');
+								sb.Append(canonicalizedVersion.Revision);
+							}
+						}
+					}
+				}
+			}
+
+			string cultureName = a.CultureName;
+			if (cultureName != null)
+			{
+				if (cultureName == string.Empty)
+					cultureName = "neutral";
+				sb.Append(", Culture=");
+				sb.AppendQuoted(cultureName);
+			}
+
+			byte[] pkt = a.PublicKeyOrToken;
+			if (pkt != null)
+			{
+				if (pkt.Length > PUBLIC_KEY_TOKEN_LEN)
+					throw new ArgumentException();
+
+				sb.Append(", PublicKeyToken=");
+				if (pkt.Length == 0)
+					sb.Append("null");
+				else
+				{
+					foreach (byte b in pkt)
+					{
+						sb.Append(b.ToString("x2", CultureInfo.InvariantCulture));
+					}
+				}
+			}
+
+			if (0 != (a.Flags & AssemblyNameFlags.Retargetable))
+				sb.Append(", Retargetable=Yes");
+
+			AssemblyContentType contentType = a.Flags.ExtractAssemblyContentType();
+			if (contentType == AssemblyContentType.WindowsRuntime)
+				sb.Append(", ContentType=WindowsRuntime");
+
+			// NOTE: By design (desktop compat) AssemblyName.FullName and ToString() do not include ProcessorArchitecture.
+
+			return sb.ToString();
+		}
+
+		private static void AppendQuoted(this StringBuilder sb, string s)
+		{
+			bool needsQuoting = false;
+			const char quoteChar = '\"';
+
+			// App-compat: You can use double or single quotes to quote a name, and Fusion (or rather the IdentityAuthority) picks one
+			// by some algorithm. Rather than guess at it, we use double quotes consistently.
+			if (s != s.Trim() || s.Contains("\"") || s.Contains("\'"))
+				needsQuoting = true;
+
+			if (needsQuoting)
+				sb.Append(quoteChar);
+
+			for (int i = 0; i < s.Length; i++)
+			{
+				bool addedEscape = false;
+				foreach (KeyValuePair<char, string> kv in EscapeSequences)
+				{
+					string escapeReplacement = kv.Value;
+					if (!(s[i] == escapeReplacement[0]))
+						continue;
+					if ((s.Length - i) < escapeReplacement.Length)
+						continue;
+					if (s.Substring(i, escapeReplacement.Length).Equals(escapeReplacement))
+					{
+						sb.Append('\\');
+						sb.Append(kv.Key);
+						addedEscape = true;
+					}
+				}
+
+				if (!addedEscape)
+					sb.Append(s[i]);
+			}
+
+			if (needsQuoting)
+				sb.Append(quoteChar);
+		}
+
+		private static Version CanonicalizeVersion(this Version version)
+		{
+			ushort major = (ushort)version.Major;
+			ushort minor = (ushort)version.Minor;
+			ushort build = (ushort)version.Build;
+			ushort revision = (ushort)version.Revision;
+
+			if (major == version.Major && minor == version.Minor && build == version.Build && revision == version.Revision)
+				return version;
+
+			return new Version(major, minor, build, revision);
+		}
+
+		public static KeyValuePair<char, string>[] EscapeSequences =
+		{
+			new KeyValuePair<char, string>('\\', "\\"),
+			new KeyValuePair<char, string>(',', ","),
+			new KeyValuePair<char, string>('=', "="),
+			new KeyValuePair<char, string>('\'', "'"),
+			new KeyValuePair<char, string>('\"', "\""),
+			new KeyValuePair<char, string>('n', Environment.NewLine),
+			new KeyValuePair<char, string>('t', "\t"),
+		};
+	}
+}

external/corert/src/System.Private.CoreLib/shared/System/Reflection/AssemblyNameHelpers.cs

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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Globalization;
+using System.IO;
+using System.Text;
+using System.Collections.Generic;
+
+namespace System.Reflection
+{
+	public static partial class AssemblyNameHelpers
+	{
+
+
+		//
+		// These helpers convert between the combined flags+contentType+processorArchitecture value and the separated parts.
+		//
+		// Since these are only for trusted callers, they do NOT check for out of bound bits. 
+		//
+
+		internal static AssemblyContentType ExtractAssemblyContentType(this AssemblyNameFlags flags)
+		{
+			return (AssemblyContentType)((((int)flags) >> 9) & 0x7);
+		}
+
+		internal static ProcessorArchitecture ExtractProcessorArchitecture(this AssemblyNameFlags flags)
+		{
+			return (ProcessorArchitecture)((((int)flags) >> 4) & 0x7);
+		}
+
+		public static AssemblyNameFlags ExtractAssemblyNameFlags(this AssemblyNameFlags combinedFlags)
+		{
+			return combinedFlags & unchecked((AssemblyNameFlags)0xFFFFF10F);
+		}
+
+		internal static AssemblyNameFlags CombineAssemblyNameFlags(AssemblyNameFlags flags, AssemblyContentType contentType, ProcessorArchitecture processorArchitecture)
+		{
+			return (AssemblyNameFlags)(((int)flags) | (((int)contentType) << 9) | ((int)processorArchitecture << 4));
+		}
+	}
+}

external/corert/src/System.Private.CoreLib/shared/System/Reflection/AssemblyNameLexer.cs

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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.IO;
+using System.Text;
+using System.Collections.Generic;
+
+namespace System.Reflection
+{
+	//
+	// A simple lexer for assembly display names.
+	//
+	internal struct AssemblyNameLexer
+	{
+		internal AssemblyNameLexer(string s)
+		{
+			// Convert string to char[] with NUL terminator. (An actual NUL terminator in the input string will be treated
+			// as an actual end of string: this is compatible with desktop behavior.)
+			char[] chars = new char[s.Length + 1];
+			s.CopyTo(0, chars, 0, s.Length);
+			_chars = chars;
+			_index = 0;
+		}
+
+		//
+		// Return the next token in assembly name. If you expect the result to be DisplayNameToken.String, 
+		// use GetNext(out String) instead.
+		//
+		internal Token GetNext()
+		{
+			string ignore;
+			return GetNext(out ignore);
+		}
+
+		//
+		// Return the next token in assembly name. If the result is DisplayNameToken.String, 
+		// sets "tokenString" to the tokenized string.
+		//
+		internal Token GetNext(out string tokenString)
+		{
+			tokenString = null;
+			while (char.IsWhiteSpace(_chars[_index]))
+				_index++;
+
+			char c = _chars[_index++];
+			if (c == 0)
+				return Token.End;
+			if (c == ',')
+				return Token.Comma;
+			if (c == '=')
+				return Token.Equals;
+
+			StringBuilder sb = new StringBuilder();
+
+			char quoteChar = (char)0;
+			if (c == '\'' || c == '\"')
+			{
+				quoteChar = c;
+				c = _chars[_index++];
+			}
+
+			for (; ; )
+			{
+				if (c == 0)
+				{
+					_index--;
+					break;  // Terminate: End of string (desktop compat: if string was quoted, permitted to terminate without end-quote.)
+				}
+
+				if (quoteChar != 0 && c == quoteChar)
+					break;  // Terminate: Found closing quote of quoted string.
+
+				if (quoteChar == 0 && (c == ',' || c == '='))
+				{
+					_index--;
+					break;  // Terminate: Found start of a new ',' or '=' token.
+				}
+
+				if (quoteChar == 0 && (c == '\'' || c == '\"'))
+					throw new FileLoadException();  // Desktop compat: Unescaped quote illegal unless entire string is quoted.
+
+				if (c == '\\')
+				{
+					c = _chars[_index++];
+					bool matched = false;
+					foreach (KeyValuePair<char, string> kv in AssemblyNameFormatter.EscapeSequences)
+					{
+						if (c == kv.Key)
+						{
+							matched = true;
+							sb.Append(kv.Value);
+							break;
+						}
+					}
+					if (!matched)
+						throw new FileLoadException();  // Unrecognized escape
+				}
+				else
+				{
+					sb.Append(c);
+				}
+
+				c = _chars[_index++];
+			}
+
+			tokenString = sb.ToString();
+			if (quoteChar == 0)
+				tokenString = tokenString.Trim(); // Unless quoted, whitespace at beginning or end doesn't count.
+			return Token.String;
+		}
+
+		// Token categories for display name lexer.
+		internal enum Token
+		{
+			Equals = 1,
+			Comma = 2,
+			String = 3,
+			End = 4,
+		}
+
+		private readonly char[] _chars;
+		private int _index;
+	}
+}