protected virtual IReadOnlyCollection <TagHelperDescriptor> ProduceTagHelpersFromDelta(string projectFilePath, int lastResultId, TagHelperDeltaResult deltaResult)
{
if (!_resultCache.TryGet(projectFilePath, lastResultId, out var tagHelpers))
{
// We most likely haven't made a request to the server yet so there's no delta to apply
tagHelpers = Array.Empty <TagHelperDescriptor>();
if (deltaResult.Delta)
{
// We somehow failed to retrieve a cached object yet the server was able to apply a delta. This
// is entirely unexpected and means the server & client are catastrophically de-synchronized.
throw new InvalidOperationException("This should never happen. Razor server & client are de-synchronized. Tearing down");
}
}
else if (!deltaResult.Delta)
{
// Not a delta based response, we should treat it as a "refresh"
tagHelpers = Array.Empty <TagHelperDescriptor>();
}
if (deltaResult.ResultId != lastResultId)
{
// New results, lets build a coherent TagHelper collection and then cache it
tagHelpers = deltaResult.Apply(tagHelpers);
_resultCache.Set(projectFilePath, deltaResult.ResultId, tagHelpers);
}
return(tagHelpers);
}
public void Apply_AddAndRemoved()
{
// Arrange
var delta = new TagHelperDeltaResult(Delta: true, ResultId: 1337, Project1TagHelpers, Project2TagHelpers);
// Act
var tagHelpers = delta.Apply(Project2TagHelpers);
// Assert
Assert.Equal(Project1TagHelpers, tagHelpers);
}
public void Apply_Removed()
{
// Arrange
var delta = new TagHelperDeltaResult(Delta: true, ResultId: 1337, Array.Empty <TagHelperDescriptor>(), Project1TagHelpers);
// Act
var tagHelpers = delta.Apply(Project1AndProject2TagHelpers);
// Assert
Assert.Equal(Project2TagHelpers, tagHelpers);
}