More spans (#723)

Author: SimonCropp

src/MarkdownSnippets/Extensions.cs

@@ -60,7 +60,7 @@ public static void TrimEnd(this StringBuilder builder)
 
     public static IReadOnlyList<T> ToReadonlyList<T>(this IEnumerable<T> value) => value.ToList();
 
-    public static int LineCount(this string input)
+    public static int LineCount(this CharSpan input)
     {
         var count = 1;
         var len = input.Length;
@@ -85,7 +85,7 @@ public static int LineCount(this string input)
         return count;
     }
 
-    public static int LastIndexOfSequence(this string value, char c, int max)
+    public static int LastIndexOfSequence(this CharSpan value, char c, int max)
     {
         var index = 0;
         while (true)
@@ -110,7 +110,7 @@ public static int LastIndexOfSequence(this string value, char c, int max)
         }
     }
 
-    public static string TrimBackCommentChars(this string input, int startIndex)
+    public static CharSpan TrimBackCommentChars(this CharSpan input, int startIndex)
     {
         for (var index = input.Length - 1; index >= startIndex; index--)
         {
@@ -127,6 +127,16 @@ public static string TrimBackCommentChars(this string input, int startIndex)
     public static string[] Lines(this string value) =>
         value.Split(["\r\n", "\r", "\n"], StringSplitOptions.None);
 
-    public static bool IsWhiteSpace(this string target) =>
-        string.IsNullOrWhiteSpace(target);
+    public static bool IsWhiteSpace(this CharSpan target)
+    {
+        for (var i = 0; i < target.Length; i++)
+        {
+            if (!char.IsWhiteSpace(target[i]))
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
 }

src/MarkdownSnippets/Processing/MarkdownProcessor.cs

@@ -416,9 +416,19 @@ Snippet FileToSnippet(string key, string file, string? path)
 
     (string text, int lineCount) ReadNonStartEndLines(string file)
     {
-        var cleanedLines = File.ReadAllLines(file)
-            .Where(_ => !StartEndTester.IsStartOrEnd(_.TrimStart())).ToList();
-        var text = string.Join(newLine, cleanedLines).Trim();
-        return (text, cleanedLines.Count);
+        using var reader = File.OpenText(file);
+        var lines = new List<string>();
+        while (reader.ReadLine() is { } line)
+        {
+            if (StartEndTester.IsStartOrEnd(line))
+            {
+                continue;
+            }
+
+            lines.Add(line);
+        }
+
+        var text = string.Join(newLine, lines).Trim();
+        return (text, lines.Count);
     }
 }

src/MarkdownSnippets/Processing/SimpleSnippetMarkdownHandling.cs

@@ -23,6 +23,7 @@ static void WriteSnippet(Action<string> appendLine, Snippet snippet)
         {
             appendLine($"```{snippet.Language} {snippet.ExpressiveCode}");
         }
+
         appendLine(snippet.Value);
         appendLine("```");
     }

src/MarkdownSnippets/Reading/EndFunc.cs

@@ -1 +1 @@
-delegate bool EndFunc(string line);
+delegate bool EndFunc(CharSpan line);

src/MarkdownSnippets/Reading/FileSnippetExtractor.cs

@@ -124,7 +124,7 @@ public static string GetLanguageFromPath(string path)
         var extension = Path.GetExtension(path);
         // ReSharper disable once ConstantConditionalAccessQualifier
         var s = extension?.TrimStart('.');
-        return s ?? string.Empty;
+        return s?.ToLowerInvariant() ?? string.Empty;
     }
 
     static IEnumerable<Snippet> GetSnippets(TextReader stringReader, string path, int maxWidth, string newLine)
@@ -207,7 +207,7 @@ static Snippet BuildSnippet(string path, LoopStack loopStack, string language, i
             key: loopState.Key,
             value: value,
             path: path,
-            language: language.ToLowerInvariant(),
+            language: language,
             expressiveCode: loopState.ExpressiveCode
         );
     }

src/MarkdownSnippets/Reading/IContent.cs

@@ -0,0 +1,6 @@
+namespace MarkdownSnippets;
+
+public interface IContent
+{
+    string? Path { get; }
+}

src/MarkdownSnippets/Reading/LoopStack.cs

@@ -15,9 +15,11 @@ public void AppendLine(string line)
 
     public void Pop() => stack.Pop();
 
-    public void Push(EndFunc endFunc, string key, int startLine, int maxWidth, string newLine, string? expressiveCode)
+    public void Push(EndFunc endFunc, CharSpan key, int startLine, int maxWidth, string newLine, CharSpan expressiveCode)
     {
-        var state = new LoopState(key, endFunc, startLine, maxWidth, newLine, expressiveCode);
+        var expressiveCodeString = expressiveCode.Length == 0 ? null : expressiveCode.ToString();
+
+        var state = new LoopState(key.ToString(), endFunc, startLine, maxWidth, newLine, expressiveCodeString);
         stack.Push(state);
     }
 

src/MarkdownSnippets/Reading/LoopState.cs

@@ -40,13 +40,15 @@ public void AppendLine(string line)
                 builder.Append(newLine);
             }
         }
+
         var paddingToRemove = line.LastIndexOfSequence(paddingChar, paddingLength);
 
         var lineLength = line.Length - paddingToRemove;
         if (lineLength > maxWidth)
         {
-            throw new LineTooLongException(line.Substring(paddingToRemove,lineLength));
+            throw new LineTooLongException(line.Substring(paddingToRemove, lineLength));
         }
+
         builder.Append(line, paddingToRemove, lineLength);
         if (line.Length == 0)
         {
@@ -58,7 +60,7 @@ public void AppendLine(string line)
         }
     }
 
-    void CheckWhiteSpace(string line, char whiteSpace)
+    void CheckWhiteSpace(CharSpan line, char whiteSpace)
     {
         var c = line[0];
         if (c != whiteSpace)

src/MarkdownSnippets/Reading/Snippet.cs

@@ -139,9 +139,4 @@ public override string ToString() =>
            Error: {Error}
 
          """;
-}
-
-public interface IContent
-{
-    string? Path { get; }
 }

src/MarkdownSnippets/Reading/StartEndTester.cs

@@ -1,17 +1,20 @@
 static class StartEndTester
 {
-    internal static bool IsStartOrEnd(string trimmedLine) =>
-        IsBeginSnippet(trimmedLine) ||
-        IsEndSnippet(trimmedLine) ||
-        IsStartRegion(trimmedLine) ||
-        IsEndRegion(trimmedLine);
+    internal static bool IsStartOrEnd(CharSpan line)
+    {
+        var trimmedLine = line.Trim();
+        return IsBeginSnippet(trimmedLine) ||
+               IsEndSnippet(trimmedLine) ||
+               IsStartRegion(trimmedLine) ||
+               IsEndRegion(trimmedLine);
+    }
 
     internal static bool IsStart(
-        string trimmedLine,
-        string path,
-        [NotNullWhen(true)] out string? currentKey,
+        CharSpan trimmedLine,
+        CharSpan path,
+        out CharSpan currentKey,
         [NotNullWhen(true)] out EndFunc? endFunc,
-        out string? expressiveCode)
+        out CharSpan expressiveCode)
     {
         if (IsBeginSnippet(trimmedLine, path, out currentKey, out expressiveCode))
         {
@@ -35,18 +38,18 @@ internal static bool IsStart(
 
     static EndFunc throwFunc = _ => throw new("Do not use out func");
 
-    static bool IsEndRegion(string line) =>
+    static bool IsEndRegion(CharSpan line) =>
         line.StartsWith("#endregion", StringComparison.Ordinal);
 
-    static bool IsEndSnippet(string line) =>
+    static bool IsEndSnippet(CharSpan line) =>
         IndexOf(line, "end-snippet") >= 0;
 
-    static bool IsStartRegion(string line) =>
+    static bool IsStartRegion(CharSpan line) =>
         line.StartsWith("#region ", StringComparison.Ordinal);
 
     internal static bool IsStartRegion(
-        string line,
-        [NotNullWhen(true)] out string? key)
+        CharSpan line,
+        out CharSpan key)
     {
         if (!line.StartsWith("#region ", StringComparison.Ordinal))
         {
@@ -56,33 +59,28 @@ internal static bool IsStartRegion(
 
         var substring = line[8..].Trim();
 
-        if (substring.Contains(' '))
+        if (substring.Contains(' ') ||
+            !KeyValidator.IsValidKey(substring))
         {
             key = null;
             return false;
         }
 
-        if (!KeyValidator.IsValidKey(substring.AsSpan()))
-        {
-            key = null;
-            return false;
-        }
-
-        key = substring;
+        key = substring.ToString();
         return true;
     }
 
-    static bool IsBeginSnippet(string line)
+    static bool IsBeginSnippet(CharSpan line)
     {
         var startIndex = IndexOf(line, "begin-snippet: ");
         return startIndex != -1;
     }
 
     internal static bool IsBeginSnippet(
-        string line,
-        string path,
-        [NotNullWhen(true)] out string? key,
-        out string? expressiveCode)
+        CharSpan line,
+        CharSpan path,
+        out CharSpan key,
+        out CharSpan expressiveCode)
     {
         expressiveCode = null;
         var beginSnippetIndex = IndexOf(line, "begin-snippet: ");
@@ -117,11 +115,7 @@ internal static bool IsBeginSnippet(
                      """);
             }
 
-            expressiveCode = substring[(startArgs +1)..^1].Trim();
-            if (expressiveCode.Length == 0)
-            {
-                expressiveCode = null;
-            }
+            expressiveCode = substring[(startArgs + 1)..^1].Trim();
         }
 
         if (key.Length == 0)
@@ -134,7 +128,7 @@ No Key could be derived.
                  """);
         }
 
-        if (KeyValidator.IsValidKey(key.AsSpan()))
+        if (KeyValidator.IsValidKey(key))
         {
             return true;
         }
@@ -148,14 +142,14 @@ Key cannot contain whitespace or start/end with symbols.
              """);
     }
 
-    static int IndexOf(string line, string value)
+    static int IndexOf(CharSpan line, CharSpan value)
     {
         if (value.Length > line.Length)
         {
             return -1;
         }
 
         var charactersToScan = Math.Min(line.Length, value.Length + 10);
-        return line.IndexOf(value, startIndex: 0, count: charactersToScan, StringComparison.Ordinal);
+        return line[..charactersToScan].IndexOf(value, StringComparison.Ordinal);
     }
 }