Umbraco-CMS/src/Umbraco.Web.Website/ViewEngines/ProfilingViewEngine.cs

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.ViewEngines;
using Umbraco.Cms.Core.Logging;

namespace Umbraco.Cms.Web.Website.ViewEngines
{
    public class ProfilingViewEngine: IViewEngine
    {
        internal readonly IViewEngine Inner;
        private readonly IProfiler _profiler;
        private readonly string _name;

        public ProfilingViewEngine(IViewEngine inner, IProfiler profiler)
        {
            Inner = inner;
            _profiler = profiler;
            _name = inner.GetType().Name;
        }

        public ViewEngineResult FindView(ActionContext context, string viewName, bool isMainPage)
        {
            using (_profiler.Step(string.Format("{0}.FindView, {1}, {2}", _name, viewName, isMainPage)))
            {
                return WrapResult(Inner.FindView(context, viewName, isMainPage));
            }
        }

        private static ViewEngineResult WrapResult(ViewEngineResult innerResult)
        {
            var profiledResult = innerResult.View is null
                ? ViewEngineResult.NotFound(innerResult.ViewName, innerResult.SearchedLocations)
                : ViewEngineResult.Found(innerResult.ViewName, innerResult.View);
            return profiledResult;
        }

        public ViewEngineResult GetView(string executingFilePath, string viewPath, bool isMainPage)
        {
            using (_profiler.Step(string.Format("{0}.GetView, {1}, {2}, {3}", _name, executingFilePath, viewPath, isMainPage)))
            {
                return Inner.GetView(executingFilePath, viewPath, isMainPage);
            }
        }
    }
}