static bool ShouldRunGenerator (ProjectFile file, Project project, bool force, out SingleProjectFileCustomTool tool, out ProjectFile genFile)
		{
			tool = null;
			genFile = null;

			//ignore cloned file from shared project in context of referencing project
			if ((file.Flags & ProjectItemFlags.DontPersist) != 0) {
				return false;
			}

			tool = GetGenerator (file.Generator);
			if (tool == null) {
				return false;
			}

			if (project == null) {
				// this might happen if the file is being removed from the project. Ideally we wouldn't hit this path
				// because if we use the overload with the project param then we can pass the appropriate project
				return false;
			}

			//ignore MSBuild tool for projects that aren't MSBuild or can't build
			//we could emit a warning but this would get very annoying for Xamarin Forms + SAP
			//in future we could consider running the MSBuild generator in context of every referencing project
			if (tool is MSBuildCustomTool) {
				if (!project.SupportsBuild ()) {
					return false;
				}
				bool byDefault, require;
				MonoDevelop.Projects.MSBuild.MSBuildProjectService.CheckHandlerUsesMSBuildEngine (project, out byDefault, out require);
				var usesMSBuild = require || (project.UseMSBuildEngine ?? byDefault);
				if (!usesMSBuild) {
					return false;
				}
			}

			if (!string.IsNullOrEmpty (file.LastGenOutput)) {
				genFile = project.Files.GetFile (file.FilePath.ParentDirectory.Combine (file.LastGenOutput));
			}

			return force
				|| genFile == null
				|| !File.Exists (genFile.FilePath)
				|| File.GetLastWriteTime (file.FilePath) > File.GetLastWriteTime (genFile.FilePath);
		}