private static void compile(
      LanguageService languageService, List<FileDelta> fileDeltas, IProgressMonitor monitor)
      throws CoreException {
    for (FileDelta fileDelta : fileDeltas) {
      Delta delta = fileDelta.getDelta();

      if (delta == Delta.ADDED || delta == Delta.CHANGED) {
        String fileName = fileDelta.getFileName();

        // skip ambient declaration files
        if (fileName.endsWith("d.ts")) {
          continue;
        }

        // compile the file
        try {
          compile(fileName, languageService, monitor);
        } catch (RuntimeException e) {
          String errorMessage = "Compilation of '" + fileName + "' failed.";
          Status status = new Status(IStatus.ERROR, TypeScriptPlugin.ID, errorMessage, e);

          TypeScriptPlugin.getDefault().getLog().log(status);
        }
      }
    }
  }
  private void clean(List<FileDelta> fileDeltas, IProgressMonitor monitor) throws CoreException {
    // clear the problem markers
    this.getProject().deleteMarkers(MARKER_TYPE, true, IResource.DEPTH_INFINITE);

    // remove the built files if compile-on-save is enabled
    IPreferenceStore preferenceStore = TypeScriptPlugin.getDefault().getPreferenceStore();
    if (preferenceStore.getBoolean(IPreferenceConstants.COMPILER_COMPILE_ON_SAVE)) {
      for (FileDelta fileDelta : fileDeltas) {
        String fileName = fileDelta.getFileName();
        ImmutableList<String> builtFiles = getBuiltFiles(fileName);

        for (String builtFile : builtFiles) {
          Path path = new Path(builtFile);
          IFile file = ResourcesPlugin.getWorkspace().getRoot().getFileForLocation(path);

          file.refreshLocal(IResource.DEPTH_ZERO, monitor);
          if (file.exists()) {
            file.delete(false, monitor);
          }
        }
      }
    }
  }