Move CoreRT specific String class bits to its own file (#5478)

3 files changed, 86 insertions, 64 deletions

diff --git a/src/System.Private.CoreLib/src/System.Private.CoreLib.csproj b/src/System.Private.CoreLib/src/System.Private.CoreLib.csproj
index bd1371f69..9f041c462 100644
--- a/src/System.Private.CoreLib/src/System.Private.CoreLib.csproj
+++ b/src/System.Private.CoreLib/src/System.Private.CoreLib.csproj
@@ -273,6 +273,7 @@
     <Compile Include="System\Runtime\Serialization\SerializationInfo.cs" />
     <Compile Include="System\String.cs" />
     <Compile Include="System\String.Comparison.cs" />
+    <Compile Include="System\String.CoreRT.cs" />
     <Compile Include="System\String.Intern.cs" />
     <Compile Include="System\Array.cs" />
     <Compile Include="System\Array.CoreRT.cs" />
diff --git a/src/System.Private.CoreLib/src/System/String.CoreRT.cs b/src/System.Private.CoreLib/src/System/String.CoreRT.cs
new file mode 100644
index 000000000..a892006d9
--- /dev/null
+++ b/src/System.Private.CoreLib/src/System/String.CoreRT.cs
@@ -0,0 +1,85 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Globalization;
+using System.Runtime;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
+using System.Text;
+
+using Internal.Runtime.CompilerServices;
+
+namespace System
+{
+    [StructLayout(LayoutKind.Sequential)]
+    [System.Runtime.CompilerServices.EagerStaticClassConstructionAttribute]
+    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
+    public partial class String
+    {
+#if BIT64
+        private const int POINTER_SIZE = 8;
+#else
+        private const int POINTER_SIZE = 4;
+#endif
+        //                                        m_pEEType    + _stringLength
+        internal const int FIRST_CHAR_OFFSET = POINTER_SIZE + sizeof(int);
+
+        // CS0169: The private field '{blah}' is never used
+        // CS0649: Field '{blah}' is never assigned to, and will always have its default value
+#pragma warning disable 169, 649
+
+#if PROJECTN
+        [Bound]
+#endif
+        // WARNING: We allow diagnostic tools to directly inspect these two members (_stringLength, _firstChar)
+        // See https://github.com/dotnet/corert/blob/master/Documentation/design-docs/diagnostics/diagnostics-tools-contract.md for more details. 
+        // Please do not change the type, the name, or the semantic usage of this member without understanding the implication for tools. 
+        // Get in touch with the diagnostics team if you have questions.
+        [NonSerialized]
+        private int _stringLength;
+        [NonSerialized]
+        private char _firstChar;
+
+#pragma warning restore
+
+        public static readonly String Empty = "";
+
+        // Gets the character at a specified position.
+        //
+        // Spec#: Apply the precondition here using a contract assembly.  Potential perf issue.
+        [System.Runtime.CompilerServices.IndexerName("Chars")]
+        public unsafe char this[int index]
+        {
+#if PROJECTN
+            [BoundsChecking]
+            get
+            {
+                return Unsafe.Add(ref _firstChar, index);
+            }
+#else
+            [Intrinsic]
+            get
+            {
+                if ((uint)index >= _stringLength)
+                    ThrowHelper.ThrowIndexOutOfRangeException();
+                return Unsafe.Add(ref _firstChar, index);
+            }
+#endif
+        }
+
+        internal static String FastAllocateString(int length)
+        {
+            // We allocate one extra char as an interop convenience so that our strings are null-
+            // terminated, however, we don't pass the extra +1 to the string allocation because the base
+            // size of this object includes the _firstChar field.
+            string newStr = RuntimeImports.RhNewString(EETypePtr.EETypePtrOf<string>(), length);
+            Debug.Assert(newStr._stringLength == length);
+            return newStr;
+        }
+    }
+}
diff --git a/src/System.Private.CoreLib/src/System/String.cs b/src/System.Private.CoreLib/src/System/String.cs
index 076bd02a8..6c0f7532b 100644
--- a/src/System.Private.CoreLib/src/System/String.cs
+++ b/src/System.Private.CoreLib/src/System/String.cs
@@ -74,38 +74,9 @@ namespace System
     // constructed itself depends on this class also being eagerly constructed. Plus, it's nice to have this
     // eagerly constructed to avoid the cost of defered ctors. I can't imagine any app that doesn't use string
     //
-    [StructLayout(LayoutKind.Sequential)]
-    [System.Runtime.CompilerServices.EagerStaticClassConstructionAttribute]
     [Serializable]
-    [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public sealed partial class String : IComparable, IEnumerable, IEnumerable<char>, IComparable<String>, IEquatable<String>, IConvertible, ICloneable
     {
-#if BIT64
-        private const int POINTER_SIZE = 8;
-#else
-        private const int POINTER_SIZE = 4;
-#endif
-        //                                        m_pEEType    + _stringLength
-        internal const int FIRST_CHAR_OFFSET = POINTER_SIZE + sizeof(int);
-
-        // CS0169: The private field '{blah}' is never used
-        // CS0649: Field '{blah}' is never assigned to, and will always have its default value
-#pragma warning disable 169, 649
-
-#if PROJECTN
-        [Bound]
-#endif
-        // WARNING: We allow diagnostic tools to directly inspect these two members (_stringLength, _firstChar)
-        // See https://github.com/dotnet/corert/blob/master/Documentation/design-docs/diagnostics/diagnostics-tools-contract.md for more details. 
-        // Please do not change the type, the name, or the semantic usage of this member without understanding the implication for tools. 
-        // Get in touch with the diagnostics team if you have questions.
-        [NonSerialized]
-        private int _stringLength;
-        [NonSerialized]
-        private char _firstChar;
-
-#pragma warning restore
-
         // String constructors
         // These are special. the implementation methods for these have a different signature from the
         // declared constructors.
@@ -464,31 +435,6 @@ namespace System
             return result;
         }
 
-        public static readonly String Empty = "";
-
-        // Gets the character at a specified position.
-        //
-        // Spec#: Apply the precondition here using a contract assembly.  Potential perf issue.
-        [System.Runtime.CompilerServices.IndexerName("Chars")]
-        public unsafe char this[int index]
-        {
-#if PROJECTN
-            [BoundsChecking]
-            get
-            {
-                return Unsafe.Add(ref _firstChar, index);
-            }
-#else
-            [Intrinsic]
-            get
-            {
-                if ((uint)index >= _stringLength)
-                    ThrowHelper.ThrowIndexOutOfRangeException();
-                return Unsafe.Add(ref _firstChar, index);
-            }
-#endif
-        }
-
         // Converts a substring of this string to an array of characters.  Copies the
         // characters of this string beginning at position sourceIndex and ending at
         // sourceIndex + count - 1 to the character array buffer, beginning
@@ -630,16 +576,6 @@ namespace System
             return result;
         }
 
-        internal static String FastAllocateString(int length)
-        {
-            // We allocate one extra char as an interop convenience so that our strings are null-
-            // terminated, however, we don't pass the extra +1 to the string allocation because the base
-            // size of this object includes the _firstChar field.
-            string newStr = RuntimeImports.RhNewString(EETypePtr.EETypePtrOf<string>(), length);
-            Debug.Assert(newStr._stringLength == length);
-            return newStr;
-        }
-
         internal static unsafe void wstrcpy(char* dmem, char* smem, int charCount)
         {
             Buffer.Memmove((byte*)dmem, (byte*)smem, ((uint)charCount) * 2);