internal static string Process(ref IEnumerable <BundleFile> files)
{
DotlessConfiguration lessConfig = new WebConfigConfigurationLoader().GetConfiguration();
if (!lessConfig.LessSource.GetInterfaces().Contains(typeof(IFileReaderWithResolver)))
{
lessConfig.LessSource = typeof(LessVirtualFileReader);
}
// system.Web.Optimization cache is used instead
lessConfig.CacheEnabled = false;
var content = new StringBuilder();
var targetFiles = new List <BundleFile>();
foreach (BundleFile bundleFile in files)
{
// initialize the less engine once for each file.
// this is to prevent leaking state between files
ILessEngine lessEngine = LessWeb.GetEngine(lessConfig);
LessEngine underlyingLessEngine = lessEngine.ResolveLessEngine();
Parser lessParser = underlyingLessEngine.Parser;
targetFiles.Add(bundleFile);
string filePath = bundleFile.IncludedVirtualPath;
filePath = filePath.Replace('\\', '/');
filePath = VirtualPathUtility.ToAppRelative(filePath);
lessParser.SetCurrentFilePath(filePath);
string source = bundleFile.ApplyTransforms();
string extension = VirtualPathUtility.GetExtension(filePath);
// if plain CSS file, do not transform LESS
if (lessConfig.ImportAllFilesAsLess ||
".less".Equals(extension, StringComparison.InvariantCultureIgnoreCase) ||
".less.css".Equals(extension, StringComparison.InvariantCultureIgnoreCase))
{
string lessOutput = lessEngine.TransformToCss(source, filePath);
// pass the transformation result if successful
if (lessEngine.LastTransformationSuccessful)
{
source = lessOutput;
}
else
{
// otherwise write out error message.
// the transformation error is logged in LessEngine.TransformToCss
if (lessConfig.Debug)
{
content.AppendLine(string.Format(
"/* Error occurred in LESS transformation of the file: {0}. Please see details in the dotless log */",
bundleFile.IncludedVirtualPath));
}
continue;
}
}
source = ConvertUrlsToAbsolute(bundleFile.IncludedVirtualPath, source);
content.AppendLine(source);
BundleFile[] fileDependencies = GetFileDependencies(underlyingLessEngine).ToArray();
targetFiles.AddRange(fileDependencies);
DependencyCache.SaveFileDependencies(filePath, fileDependencies.Select(file => file.IncludedVirtualPath).ToArray());
}
// include imports in bundle files to register cache dependencies
files = BundleTable.EnableOptimizations ? targetFiles.Distinct() : targetFiles;
return(content.ToString());
}