private ComponentChildContentIntermediateNode RewriteChildContent(BoundAttributeDescriptor attribute, SourceSpan?source, IntermediateNodeCollection children)
{
var childContent = new ComponentChildContentIntermediateNode()
{
BoundAttribute = attribute,
Source = source,
TypeName = attribute?.TypeName ?? BlazorApi.RenderFragment.FullTypeName,
};
// There are two cases here:
// 1. Implicit child content - the children will be non-taghelper nodes, just accept them
// 2. Explicit child content - the children will be various tag helper nodes, that need special processing.
for (var i = 0; i < children.Count; i++)
{
var child = children[i];
if (child is TagHelperBodyIntermediateNode body)
{
// The body is all of the content we want to render, the rest of the childen will
// be the attributes.
for (var j = 0; j < body.Children.Count; j++)
{
childContent.Children.Add(body.Children[j]);
}
}
else if (child is TagHelperPropertyIntermediateNode property)
{
if (property.BoundAttribute.Kind == BlazorMetadata.ChildContent.TagHelperKind)
{
// Check for each child content with a parameter name, that the parameter name is specified
// with literal text. For instance, the following is not allowed and should generate a diagnostic.
//
// <MyComponent><ChildContent Context="@Foo()">...</ChildContent></MyComponent>
if (TryGetAttributeStringContent(property, out var parameterName))
{
childContent.ParameterName = parameterName;
continue;
}
// The parameter name is invalid.
childContent.Diagnostics.Add(BlazorDiagnosticFactory.Create_ChildContentHasInvalidParameter(property.Source, property.AttributeName, attribute.Name));
continue;
}
// This is an unrecognized attribute, this is possible if you try to do something like put 'ref' on a child content.
childContent.Diagnostics.Add(BlazorDiagnosticFactory.Create_ChildContentHasInvalidAttribute(property.Source, property.AttributeName, attribute.Name));
}
else if (child is TagHelperHtmlAttributeIntermediateNode a)
{
// This is an HTML attribute on a child content.
childContent.Diagnostics.Add(BlazorDiagnosticFactory.Create_ChildContentHasInvalidAttribute(a.Source, a.AttributeName, attribute.Name));
}
else
{
// This is some other kind of node (likely an implicit child content)
childContent.Children.Add(child);
}
}
return(childContent);
}
public void VisitExtension(ComponentChildContentIntermediateNode node)
{
// Check that each child content has a unique parameter name within its scope. This is important
// because the parameter name can be implict, and it doesn't work well when nested.
if (node.IsParameterized)
{
for (var i = 0; i < Ancestors.Count - 1; i++)
{
var ancestor = Ancestors[i] as ComponentChildContentIntermediateNode;
if (ancestor != null &&
ancestor.IsParameterized &&
string.Equals(node.ParameterName, ancestor.ParameterName, StringComparison.Ordinal))
{
// Duplicate name. We report an error because this will almost certainly also lead to an error
// from the C# compiler that's way less clear.
node.Diagnostics.Add(BlazorDiagnosticFactory.Create_ChildContentRepeatedParameterName(
node.Source,
node,
(ComponentExtensionNode)Ancestors[0], // Encosing component
ancestor, // conflicting child content node
(ComponentExtensionNode)Ancestors[i + 1])); // Encosing component of conflicting child content node
}
}
}
base.VisitDefault(node);
}
public static RazorDiagnostic Create_ChildContentRepeatedParameterName(
SourceSpan?source,
ComponentChildContentIntermediateNode childContent1,
ComponentExtensionNode component1,
ComponentChildContentIntermediateNode childContent2,
ComponentExtensionNode component2)
{
Debug.Assert(childContent1.ParameterName == childContent2.ParameterName);
Debug.Assert(childContent1.IsParameterized);
Debug.Assert(childContent2.IsParameterized);
return(RazorDiagnostic.Create(
ChildContentRepeatedParameterName,
source ?? SourceSpan.Undefined,
childContent1.AttributeName,
component1.TagName,
childContent1.ParameterName,
childContent2.AttributeName,
component2.TagName));
}
public abstract void WriteComponentChildContent(CodeRenderingContext context, ComponentChildContentIntermediateNode node);