gen-proxy.js

// In addition, can always use "undefined" or makeFunction
// Forwarding proxy code based on http://wiki.ecmascript.org/doku.php?id=harmony:proxies "Example: a no-op forwarding proxy"
// The letter 'x' is special.
var proxyHandlerProperties = {
  getOwnPropertyDescriptor: {
    empty:    "function(){}",
    forward:  "function(name) { var desc = Object.getOwnPropertyDescriptor(x); desc.configurable = true; return desc; }",
    throwing: "function(name) { return {get: function() { throw 4; }, set: function() { throw 5; }}; }",
  },
  getPropertyDescriptor: {
    empty:    "function(){}",
    forward:  "function(name) { var desc = Object.getPropertyDescriptor(x); desc.configurable = true; return desc; }",
    throwing: "function(name) { return {get: function() { throw 4; }, set: function() { throw 5; }}; }",
  },
  defineProperty: {
    empty:    "function(){}",
    forward:  "function(name, desc) { Object.defineProperty(x, name, desc); }"
  },
  getOwnPropertyNames: {
    empty:    "function() { return []; }",
    forward:  "function() { return Object.getOwnPropertyNames(x); }"
  },
  delete: {
    empty:    "function() { return true; }",
    yes:      "function() { return true; }",
    no:       "function() { return false; }",
    forward:  "function(name) { return delete x[name]; }"
  },
  fix: {
    empty:    "function() { return []; }",
    yes:      "function() { return []; }",
    no:       "function() { }",
    forward:  "function() { if (Object.isFrozen(x)) { return Object.getOwnProperties(x); } }"
  },
  has: {
    empty:    "function() { return false; }",
    yes:      "function() { return true; }",
    no:       "function() { return false; }",
    forward:  "function(name) { return name in x; }"
  },
  hasOwn: {
    empty:    "function() { return false; }",
    yes:      "function() { return true; }",
    no:       "function() { return false; }",
    forward:  "function(name) { return Object.prototype.hasOwnProperty.call(x, name); }"
  },
  get: {
    empty:    "function() { return undefined }",
    forward:  "function(receiver, name) { return x[name]; }",
    bind:     "function(receiver, name) { var prop = x[name]; return (typeof prop) === 'function' ? prop.bind(x) : prop; }"
  },
  set: {
    empty:    "function() { return true; }",
    yes:      "function() { return true; }",
    no:       "function() { return false; }",
    forward:  "function(receiver, name, val) { x[name] = val; return true; }"
  },
  iterate: {
    empty:    "function() { return (function() { throw StopIteration; }); }",
    forward:  "function() { return (function() { for (var name in x) { yield name; } })(); }"
  },
  enumerate: {
    empty:    "function() { return []; }",
    forward:  "function() { var result = []; for (var name in x) { result.push(name); }; return result; }"
  },
  keys: {
    empty:    "function() { return []; }",
    forward:  "function() { return Object.keys(x); }"
  }
};

function makeProxyHandlerFactory(d, b)
{
  if (rnd(TOTALLY_RANDOM) == 2) return totallyRandom(d, b);

  if (d < 1)
    return "({/*TOODEEP*/})";

  try { // in case we screwed Object.prototype, breaking proxyHandlerProperties
    var preferred = Random.index(["empty", "forward", "yes", "no", "bind", "throwing"]);
    var fallback = Random.index(["empty", "forward"]);
    var fidelity = rnd(10);

    var handlerFactoryText = "(function handlerFactory(x) {";
    handlerFactoryText += "return {";

    if (rnd(2)) {
      // handlerFactory has an argument 'x'
      bp = b.concat(['x']);
    } else {
      // handlerFactory has no argument
      handlerFactoryText = handlerFactoryText.replace(/x/, "");
      bp = b;
    }

    for (var p in proxyHandlerProperties) {
      var funText;
      if (proxyHandlerProperties[p][preferred] && rnd(10) <= fidelity) {
        funText = proxyMunge(proxyHandlerProperties[p][preferred], p);
      } else {
        switch(rnd(7)) {
        case 0:  funText = makeFunction(d - 3, bp); break;
        case 1:  funText = "undefined"; break;
        case 2:  funText = "function() { throw 3; }"; break;
        default: funText = proxyMunge(proxyHandlerProperties[p][fallback], p);
        }
      }
      handlerFactoryText += p + ": " + funText + ", ";
    }

    handlerFactoryText += "}; })";

    return handlerFactoryText;
  } catch(e) {
    return "({/* :( */})";
  }
}

function proxyMunge(funText, p)
{
  //funText = funText.replace(/\{/, "{ var yum = 'PCAL'; dumpln(yum + 'LED: " + p + "');");
  return funText;
}

function makeProxyHandler(d, b)
{
  if (rnd(TOTALLY_RANDOM) == 2) return totallyRandom(d, b);

  return makeProxyHandlerFactory(d, b) + "(" + makeExpr(d - 3, b) + ")";
}