Improve text validation.

Directory.Build.props

@@ -12,6 +12,6 @@
     <RepositoryUrl>https://github.com/SebastianStehle/mjml-net.git</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
-    <Version>3.13.0</Version>
+    <Version>3.14.0</Version>
   </PropertyGroup>
 </Project>

Mjml.Net/IHtmlReader.cs

@@ -16,6 +16,10 @@ public interface IHtmlReader
 
     string Text { get; }
 
+    ReadOnlySpan<char> NameAsSpan { get; }
+
+    ReadOnlySpan<char> TextAsSpan { get; }
+
     bool SelfClosingElement { get; }
 
     HtmlTokenKind TokenKind { get; }

Mjml.Net/Internal/HtmlReaderWrapper.cs

@@ -1,4 +1,5 @@
 using HtmlPerformanceKit;
+using System;
 using HtmlReaderImpl = HtmlPerformanceKit.HtmlReader;
 
 namespace Mjml.Net.Internal;
@@ -24,6 +25,10 @@ internal class HtmlReaderWrapper : IHtmlReader
 
     public string Text => impl.Text;
 
+    public ReadOnlySpan<char> NameAsSpan => impl.NameAsMemory.Span;
+
+    public ReadOnlySpan<char> TextAsSpan => impl.TextAsMemory.Span;
+
     public bool SelfClosingElement => impl.SelfClosingElement;
 
     public HtmlTokenKind TokenKind => impl.TokenKind;

Mjml.Net/MjmlRenderContext.cs

@@ -64,6 +64,9 @@ public void Read(IHtmlReader reader, IComponent? parent, string? file)
         {
             var substree = reader.ReadSubtree();
 
+            // Only add the text error once per parent.
+            var hasAddedError = false;
+
             while (substree.Read())
             {
                 switch (substree.TokenKind)
@@ -74,6 +77,15 @@ public void Read(IHtmlReader reader, IComponent? parent, string? file)
                     case HtmlTokenKind.Comment when mjmlOptions.KeepComments && parent != null:
                         ReadComment(substree, parent);
                         break;
+                    case HtmlTokenKind.Text when !hasAddedError && substree.TextAsSpan.Trim().Length > 0:
+                        errors.Add(
+                            "Unexpected text content.",
+                            ValidationErrorType.UnexpectedText,
+                            Position(reader, file));
+
+                        // Only add the text error once per parent.
+                        hasAddedClosingError = true;
+                        break;
                 }
             }
         }
@@ -94,9 +106,10 @@ private void ReadElement(string name, IHtmlReader reader, IComponent? parent, st
 
         if (component == null)
         {
-            errors.Add($"Invalid element '{name}'.",
+            errors.Add(
+                $"Invalid element '{name}'.",
                 ValidationErrorType.UnknownElement,
-                position);
+                Position(reader, file));
 
             // Just skip unknown elements.
             reader.ReadInnerHtml();
@@ -110,8 +123,8 @@ private void ReadElement(string name, IHtmlReader reader, IComponent? parent, st
         // Add all binders to list, so that we can return them later to the pool.
         allBinders.Add(binder);
 
-        BindAttributes(reader, component, binder, file);
-        BindContent(reader, component, binder);
+        BindComponentAttributes(reader, component, binder, file);
+        BindComponentContent(reader, component, binder);
 
         component.SetBinder(binder);
         component.Read(reader, this, context);
@@ -131,7 +144,7 @@ private void ReadElement(string name, IHtmlReader reader, IComponent? parent, st
         }
     }
 
-    private void BindAttributes(IHtmlReader reader, IComponent component, Binder binder, string? file)
+    private void BindComponentAttributes(IHtmlReader reader, IComponent component, Binder binder, string? file)
     {
         for (var i = 0; i < reader.AttributeCount; i++)
         {
@@ -149,7 +162,7 @@ private void BindAttributes(IHtmlReader reader, IComponent component, Binder bin
         }
     }
 
-    private static void BindContent(IHtmlReader reader, IComponent component, Binder binder)
+    private static void BindComponentContent(IHtmlReader reader, IComponent component, Binder binder)
     {
         if (component.ContentType == ContentType.Text)
         {
@@ -185,29 +198,33 @@ private void ValidatingClosingState(string name, IHtmlReader reader, string? fil
             return;
         }
 
-        void AddClosingError(string message)
+        if (reader.TokenKind == HtmlTokenKind.EndTag && reader.Name != name)
         {
-            errors.Add(message,
+            errors.Add(
+                $"Unexpected end element, expected '{name}', got '{reader.Name}'.",
                 ValidationErrorType.InvalidHtml,
-                new SourcePosition(
-                    reader.LineNumber,
-                    reader.LinePosition,
-                    file));
+                Position(reader, name));
 
             // Only show one closing error, otherwise we could get one for every item in the hierarchy.
             hasAddedClosingError = true;
         }
-
-        if (reader.TokenKind == HtmlTokenKind.EndTag && reader.Name != name)
-        {
-            AddClosingError($"Unexpected end element, expected '{name}', got '{reader.Name}'.");
-        }
         else if (reader.TokenKind != HtmlTokenKind.EndTag)
         {
-            AddClosingError($"Unexpected end element, expected '{name}', got '{reader.TokenKind}' token.");
+            errors.Add(
+                $"Unexpected end element, expected '{name}', got '{reader.TokenKind}' token.",
+                ValidationErrorType.InvalidHtml,
+                Position(reader, name));
+
+            // Only show one closing error, otherwise we could get one for every item in the hierarchy.
+            hasAddedClosingError = true;
         }
     }
 
+    private static SourcePosition Position(IHtmlReader reader, string? file)
+    {
+        return new SourcePosition(reader.LineNumber, reader.LinePosition, file);
+    }
+
     private void Cleanup()
     {
         foreach (var usedBinder in allBinders)

Mjml.Net/ValidationErrors.cs

@@ -11,6 +11,7 @@ public enum ValidationErrorType
     InvalidParent,
     UnknownAttribute,
     UnknownElement,
+    UnexpectedText,
     InvalidHtml
 }
 

Mjml.Net/Validators/SoftValidator.cs

@@ -5,7 +5,6 @@ public sealed class SoftValidator : ValidatorBase
     public static readonly SoftValidator Instance = new SoftValidator();
 
     private SoftValidator()
-        : base(false)
     {
     }
 }

Mjml.Net/Validators/StrictValidator.cs

@@ -5,7 +5,16 @@ public sealed class StrictValidator : ValidatorBase
     public static readonly StrictValidator Instance = new StrictValidator();
 
     private StrictValidator()
-        : base(true)
     {
     }
+
+    public override void AttributeValue(string name, string value, IComponent component, IType type, ValidationErrors errors, ref ValidationContext context)
+    {
+        if (!type.Validate(value, ref context))
+        {
+            errors.Add($"'{value}' is not a valid attribute '{name}' of '{component.ComponentName}'.",
+                ValidationErrorType.InvalidAttribute,
+                context.Position);
+        }
+    }
 }

Mjml.Net/Validators/ValidatorBase.cs

@@ -5,11 +5,8 @@ namespace Mjml.Net.Validators;
 
 public abstract class ValidatorBase : IValidator
 {
-    private readonly bool validateAttributeValue;
-
-    protected ValidatorBase(bool validateAttributeValue)
+    protected ValidatorBase()
     {
-        this.validateAttributeValue = validateAttributeValue;
     }
 
     public void Attribute(string name, string value, IComponent component, ValidationErrors errors, ref ValidationContext context)
@@ -27,14 +24,16 @@ public void Attribute(string name, string value, IComponent component, Validatio
                 ValidationErrorType.UnknownAttribute,
                 context.Position);
         }
-        else if (validateAttributeValue && !attribute.Validate(value, ref context))
+        else
         {
-            errors.Add($"'{value}' is not a valid attribute '{name}' of '{component.ComponentName}'.",
-                ValidationErrorType.InvalidAttribute,
-                context.Position);
+            AttributeValue(name, value, component, attribute, errors, ref context);
         }
     }
 
+    public virtual void AttributeValue(string name, string value, IComponent component, IType type, ValidationErrors errors, ref ValidationContext context)
+    {
+    }
+
     public void Components(IComponent root, ValidationErrors errors, ref ValidationContext context)
     {
         if (root is RootComponent rootComponent)

Tests/ValidationTests.cs

@@ -125,6 +125,40 @@ public void Should_add_error_if_component_has_invalid_attribute_value()
         Assert.Equal(new[] { "'red' is not a valid attribute 'width' of 'mj-button'." }, errors);
     }
 
+    [Fact]
+    public void Should_add_error_if_component_has_unexpected_text()
+    {
+        var source = @"
+<mjml>
+    <mj-body>
+        <mj-section>
+            hello
+        </mj-section>
+    </mj-body>
+</mjml>
+";
+        var errors = Render(source);
+
+        Assert.Equal(new[] { "Unexpected text content." }, errors);
+    }
+
+    [Fact]
+    public void Should_add_error_if_component_has_unexpected_html_child()
+    {
+        var source = @"
+<mjml>
+    <mj-body>
+        <mj-section>
+            <button></button>
+        </mj-section>
+    </mj-body>
+</mjml>
+";
+        var errors = Render(source);
+
+        Assert.Equal(new[] { "Invalid element 'button'." }, errors);
+    }
+
     [Fact]
     public void Should_not_add_error_for_self_closing_element()
     {