private void AddAllowedChildrenCompletions(
ElementCompletionContext completionContext,
Dictionary <string, HashSet <TagHelperDescriptor> > elementCompletions)
{
if (completionContext.ContainingTagName == null)
{
// If we're at the root then there's no containing TagHelper to specify allowed children.
return;
}
var prefix = completionContext.DocumentContext.Prefix ?? string.Empty;
var binding = _tagHelperFactsService.GetTagHelperBinding(
completionContext.DocumentContext,
completionContext.ContainingTagName,
completionContext.Attributes,
completionContext.ContainingParentTagName);
if (binding == null)
{
// Containing tag is not a TagHelper; therefore, it allows any children.
return;
}
foreach (var descriptor in binding.Descriptors)
{
foreach (var childTag in descriptor.AllowedChildTags)
{
var prefixedName = string.Concat(prefix, childTag.Name);
var descriptors = _tagHelperFactsService.GetTagHelpersGivenTag(
completionContext.DocumentContext,
prefixedName,
completionContext.ContainingTagName);
if (descriptors.Count == 0)
{
if (!elementCompletions.ContainsKey(prefixedName))
{
elementCompletions[prefixedName] = _emptyHashSet;
}
continue;
}
if (!elementCompletions.TryGetValue(prefixedName, out var existingRuleDescriptors))
{
existingRuleDescriptors = new HashSet <TagHelperDescriptor>();
elementCompletions[prefixedName] = existingRuleDescriptors;
}
existingRuleDescriptors.UnionWith(descriptors);
}
}
}
private static ElementCompletionContext BuildElementCompletionContext(
IEnumerable <TagHelperDescriptor> descriptors,
IEnumerable <string> existingCompletions,
string containingTagName,
string containingParentTagName = "body",
string tagHelperPrefix = "")
{
var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, descriptors);
var completionContext = new ElementCompletionContext(
documentContext,
existingCompletions,
containingTagName,
attributes: Enumerable.Empty <KeyValuePair <string, string> >(),
containingParentTagName: containingParentTagName,
inHTMLSchema: (tag) => tag == "strong" || tag == "b" || tag == "bold" || tag == "li" || tag == "div");
return(completionContext);
}
public override ElementCompletionResult GetElementCompletions(ElementCompletionContext completionContext)
{
if (completionContext == null)
{
throw new ArgumentNullException(nameof(completionContext));
}
var elementCompletions = new Dictionary <string, HashSet <TagHelperDescriptor> >(StringComparer.OrdinalIgnoreCase);
AddAllowedChildrenCompletions(completionContext, elementCompletions);
if (elementCompletions.Count > 0)
{
// If the containing element is already a TagHelper and only allows certain children.
var emptyResult = ElementCompletionResult.Create(elementCompletions);
return(emptyResult);
}
elementCompletions = completionContext.ExistingCompletions.ToDictionary(
completion => completion,
_ => new HashSet <TagHelperDescriptor>(),
StringComparer.OrdinalIgnoreCase);
var catchAllDescriptors = new HashSet <TagHelperDescriptor>();
var prefix = completionContext.DocumentContext.Prefix ?? string.Empty;
var possibleChildDescriptors = _tagHelperFactsService.GetTagHelpersGivenParent(completionContext.DocumentContext, completionContext.ContainingTagName);
foreach (var possibleDescriptor in possibleChildDescriptors)
{
var addRuleCompletions = false;
var outputHint = possibleDescriptor.TagOutputHint;
foreach (var rule in possibleDescriptor.TagMatchingRules)
{
if (rule.TagName == TagHelperMatchingConventions.ElementCatchAllName)
{
catchAllDescriptors.Add(possibleDescriptor);
}
else if (elementCompletions.ContainsKey(rule.TagName))
{
addRuleCompletions = true;
}
else if (outputHint != null)
{
// If the current descriptor has an output hint we need to make sure it shows up only when its output hint would normally show up.
// Example: We have a MyTableTagHelper that has an output hint of "table" and a MyTrTagHelper that has an output hint of "tr".
// If we try typing in a situation like this: <body > | </body>
// We'd expect to only get "my-table" as a completion because the "body" tag doesn't allow "tr" tags.
addRuleCompletions = elementCompletions.ContainsKey(outputHint);
}
else if (!completionContext.InHTMLSchema(rule.TagName))
{
// If there is an unknown HTML schema tag that doesn't exist in the current completion we should add it. This happens for
// TagHelpers that target non-schema oriented tags.
addRuleCompletions = true;
}
if (addRuleCompletions)
{
UpdateCompletions(prefix + rule.TagName, possibleDescriptor);
}
}
}
// We needed to track all catch-alls and update their completions after all other completions have been completed.
// This way, any TagHelper added completions will also have catch-alls listed under their entries.
foreach (var catchAllDescriptor in catchAllDescriptors)
{
foreach (var completionTagName in elementCompletions.Keys)
{
if (elementCompletions[completionTagName].Count > 0 ||
!string.IsNullOrEmpty(prefix) && completionTagName.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
{
// The current completion either has other TagHelper's associated with it or is prefixed with a non-empty
// TagHelper prefix.
UpdateCompletions(completionTagName, catchAllDescriptor);
}
}
}
var result = ElementCompletionResult.Create(elementCompletions);
return(result);
void UpdateCompletions(string tagName, TagHelperDescriptor possibleDescriptor)
{
if (!elementCompletions.TryGetValue(tagName, out var existingRuleDescriptors))
{
existingRuleDescriptors = new HashSet <TagHelperDescriptor>();
elementCompletions[tagName] = existingRuleDescriptors;
}
existingRuleDescriptors.Add(possibleDescriptor);
}
}