Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Activities/System/Activities/Debugger/DocumentLocation.cs

@@ -0,0 +1,74 @@
+// <copyright>
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+
+namespace System.Activities.Debugger
+{
+    using System.Diagnostics;
+
+    // Immutable, lineNumber and linePosition always non-null.
+    [DebuggerDisplay("({LineNumber.Value}:{LinePosition.Value})")]
+    internal class DocumentLocation : IEquatable<DocumentLocation>, IComparable<DocumentLocation>
+    {
+        private OneBasedCounter lineNumber;
+        private OneBasedCounter linePosition;
+
+        internal DocumentLocation(OneBasedCounter lineNumber, OneBasedCounter linePosition)
+        {
+            UnitTestUtility.Assert(lineNumber != null, "lineNumber should not be null.");
+            UnitTestUtility.Assert(linePosition != null, "linePosition should not be null.");
+            this.lineNumber = lineNumber;
+            this.linePosition = linePosition;
+        }
+
+        internal DocumentLocation(int lineNumber, int linePosition)
+            : this(new OneBasedCounter(lineNumber), new OneBasedCounter(linePosition))
+        {
+        }
+
+        internal OneBasedCounter LineNumber
+        {
+            get { return this.lineNumber; }
+        }
+
+        internal OneBasedCounter LinePosition
+        {
+            get { return this.linePosition; }
+        }
+
+        public bool Equals(DocumentLocation that)
+        {
+            if (that == null)
+            {
+                return false;
+            }
+
+            return (this.lineNumber.Value == that.lineNumber.Value) && (this.linePosition.Value == that.linePosition.Value);
+        }
+
+        public override int GetHashCode()
+        {
+            return this.lineNumber.Value.GetHashCode() ^ this.linePosition.Value.GetHashCode();
+        }
+
+        public int CompareTo(DocumentLocation that)
+        {
+            if (that == null)
+            {
+                // Following the convention we have in System.Int32 that anything is considered bigger than null.
+                return 1;
+            }
+
+            if (this.lineNumber.Value == that.lineNumber.Value)
+            {
+                // The subtraction of two numbers >= 1 must not underflow integer.
+                return this.linePosition.Value - that.linePosition.Value;
+            }
+            else
+            {
+                // The subtraction of two numbers >= 1 must not underflow integer.
+                return this.lineNumber.Value - that.lineNumber.Value;
+            }
+        }
+    }
+}