secure-interface.js

const ethUtil = require('ethereumjs-util')

module.exports = secureInterface

function secureInterface (trie) {
  // overwrites
  trie.copy = copy.bind(trie, trie.copy.bind(trie))
  trie.get = get.bind(trie, trie.get.bind(trie))
  trie.put = put.bind(trie, trie.put.bind(trie))
  trie.del = del.bind(trie, trie.del.bind(trie))
}

// adds the interface when copying the trie
function copy (_super) {
  var trie = _super()
  secureInterface(trie)
  return trie
}

function get (_super, key, cb) {
  var hash = ethUtil.sha3(key)
  _super(hash, cb)
}

// for a falsey value, use the original key
// to avoid double hashing the key
function put (_super, key, val, cb) {
  if (!val) {
    this.del(key, cb)
  } else {
    var hash = ethUtil.sha3(key)
    _super(hash, val, cb)
  }
}

function del (_super, key, cb) {
  var hash = ethUtil.sha3(key)
  _super(hash, cb)
}