Optimize SourceLineNumber and add support for setting Parent

1 files changed, 80 insertions, 43 deletions

diff --git a/src/WixToolset.Data/SourceLineNumber.cs b/src/WixToolset.Data/SourceLineNumber.cs
index 8ec65201..970f17e7 100644
--- a/src/WixToolset.Data/SourceLineNumber.cs
+++ b/src/WixToolset.Data/SourceLineNumber.cs
@@ -35,10 +35,34 @@ namespace WixToolset.Data
         }
 
         /// <summary>
+        /// Constructor for a source with a parent and no line information.
+        /// </summary>
+        /// <param name="fileName">File name of the source.</param>
+        /// <param name="parent">Parent of this source line number</param>
+        public SourceLineNumber(string fileName, SourceLineNumber parent)
+        {
+            this.FileName = fileName;
+            this.Parent = parent;
+        }
+
+        /// <summary>
+        /// Constructor for a source with a parent and line information.
+        /// </summary>
+        /// <param name="fileName">File name of the source.</param>
+        /// <param name="parent">Parent of this source line number</param>
+        /// <param name="lineNumber">Line number of the source.</param>
+        public SourceLineNumber(string fileName, SourceLineNumber parent, int lineNumber)
+        {
+            this.FileName = fileName;
+            this.Parent = parent;
+            this.LineNumber = lineNumber;
+        }
+
+        /// <summary>
         /// Gets the file name of the source.
         /// </summary>
         /// <value>File name for the source.</value>
-        public string FileName { get; private set; }
+        public string FileName { get; }
 
         /// <summary>
         /// Gets or sets the line number of the source.
@@ -49,19 +73,13 @@ namespace WixToolset.Data
         /// <summary>
         /// Gets or sets the parent source line number that included this source line number.
         /// </summary>
-        public SourceLineNumber Parent { get; set; }
+        public SourceLineNumber Parent { get; private set; }
 
         /// <summary>
         /// Gets the file name and line information.
         /// </summary>
         /// <value>File name and line information.</value>
-        public string QualifiedFileName
-        {
-            get
-            {
-                return this.LineNumber.HasValue ? String.Concat(this.FileName, "*", this.LineNumber) : this.FileName;
-            }
-        }
+        public string QualifiedFileName => this.LineNumber.HasValue ? String.Concat(this.FileName, "*", this.LineNumber) : this.FileName;
 
         internal static SourceLineNumber Deserialize(JsonObject jsonObject)
         {
@@ -101,37 +119,46 @@ namespace WixToolset.Data
         /// <param name="encodedSourceLineNumbers">Encoded string to parse.</param>
         public static SourceLineNumber CreateFromEncoded(string encodedSourceLineNumbers)
         {
-            string[] linesSplit = encodedSourceLineNumbers.Split('|');
+            var linesSplitIndex = encodedSourceLineNumbers.IndexOf('|');
 
-            SourceLineNumber first = null;
-            SourceLineNumber parent = null;
-            for (int i = 0; i < linesSplit.Length; ++i)
+            // The most common case is that there is a single encoded line,
+            // so optimize for that case.
+            if (linesSplitIndex < 0)
             {
-                string[] filenameSplit = linesSplit[i].Split('*');
-                SourceLineNumber source;
-
-                if (2 == filenameSplit.Length)
-                {
-                    source = new SourceLineNumber(filenameSplit[0], Convert.ToInt32(filenameSplit[1]));
-                }
-                else
-                {
-                    source = new SourceLineNumber(filenameSplit[0]);
-                }
+                return DecodeSourceLineNumber(encodedSourceLineNumbers, 0, -1);
+            }
+            else // decode the multiple lines.
+            {
+                var startLine = 0;
 
-                if (null != parent)
+                SourceLineNumber first = null;
+                SourceLineNumber parent = null;
+                while (startLine < encodedSourceLineNumbers.Length)
                 {
-                    parent.Parent = source;
+                    var source = DecodeSourceLineNumber(encodedSourceLineNumbers, startLine, linesSplitIndex - 1);
+
+                    if (null != parent)
+                    {
+                        parent.Parent = source;
+                    }
+
+                    parent = source;
+                    if (null == first)
+                    {
+                        first = parent;
+                    }
+
+                    if (linesSplitIndex < 0)
+                    {
+                        break;
+                    }
+
+                    startLine = linesSplitIndex + 1;
+                    linesSplitIndex = encodedSourceLineNumbers.IndexOf('|', startLine);
                 }
 
-                parent = source;
-                if (null == first)
-                {
-                    first = parent;
-                }
+                return first;
             }
-
-            return first;
         }
 
         /// <summary>
@@ -159,11 +186,8 @@ namespace WixToolset.Data
         /// <param name="offset">Optional line number offset into XML file not already included in the line information.</param>
         public static SourceLineNumber CreateFromXObject(XObject node, int offset = 0)
         {
-            string uri = node.BaseUri;
-            IXmlLineInfo lineInfo = node as IXmlLineInfo;
-
-            SourceLineNumber result = CreateFromUri(uri);
-            if (null != result && null != lineInfo)
+            var result = CreateFromUri(node.BaseUri);
+            if (null != result && node is IXmlLineInfo lineInfo)
             {
                 result.LineNumber = lineInfo.LineNumber + offset;
             }
@@ -191,12 +215,12 @@ namespace WixToolset.Data
         /// </summary>
         public string GetEncoded()
         {
-            StringBuilder sb = new StringBuilder(this.QualifiedFileName);
+            var sb = new StringBuilder(this.QualifiedFileName);
 
-            for (SourceLineNumber source = this.Parent; null != source; source = source.Parent)
+            for (var parent = this.Parent; null != parent; parent = parent.Parent)
             {
                 sb.Append("|");
-                sb.Append(source.QualifiedFileName);
+                sb.Append(parent.QualifiedFileName);
             }
 
             return sb.ToString();
@@ -209,8 +233,7 @@ namespace WixToolset.Data
         /// <returns>True if SourceLineNumbers are equivalent.</returns>
         public override bool Equals(object obj)
         {
-            SourceLineNumber other = obj as SourceLineNumber;
-            return null != other &&
+            return obj is SourceLineNumber other &&
                    this.LineNumber.HasValue == other.LineNumber.HasValue &&
                    (!this.LineNumber.HasValue || this.LineNumber == other.LineNumber) &&
                    this.FileName.Equals(other.FileName, StringComparison.OrdinalIgnoreCase) &&
@@ -234,5 +257,19 @@ namespace WixToolset.Data
         {
             return this.LineNumber.HasValue && !String.IsNullOrEmpty(this.FileName) ? String.Concat(this.FileName, "(", this.LineNumber, ")") : this.FileName ?? String.Empty;
         }
+
+        private static SourceLineNumber DecodeSourceLineNumber(string encoded, int startIndex, int endIndex)
+        {
+            if (endIndex < 0)
+            {
+                endIndex = encoded.Length - 1;
+            }
+
+            var count = endIndex - startIndex;
+            var filenameSplitIndex = encoded.LastIndexOf('*', endIndex - 1, count);
+            return (filenameSplitIndex < 0) ? new SourceLineNumber(encoded) :
+                                              new SourceLineNumber(encoded.Substring(startIndex, filenameSplitIndex - startIndex),
+                                                                   Convert.ToInt32(encoded.Substring(filenameSplitIndex + 1, endIndex - filenameSplitIndex)));
+        }
     }
 }