@Nullable
public VirtualFile findAppDirectory(@Nullable PsiElement element) {
if (element == null) return null;
PsiFile containingFile = element.getContainingFile().getOriginalFile();
VirtualFile file = containingFile.getVirtualFile();
if (file == null) return null;
ProjectFileIndex index =
ProjectRootManager.getInstance(containingFile.getProject()).getFileIndex();
VirtualFile root = index.getContentRootForFile(file);
if (root == null) return null;
return root.findChild(getApplicationDirectoryName());
}
