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author | Florian Dold <florian.dold@gmail.com> | 2017-05-28 00:38:50 +0200 |
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committer | Florian Dold <florian.dold@gmail.com> | 2017-05-28 00:40:43 +0200 |
commit | 7fff4499fd915bcea3fa93b1aa8b35f4fe7a6027 (patch) | |
tree | 6de9a1aebd150a23b7f8c273ec657a5d0a18fe3e /node_modules/private | |
parent | 963b7a41feb29cc4be090a2446bdfe0c1f1bcd81 (diff) | |
download | wallet-core-7fff4499fd915bcea3fa93b1aa8b35f4fe7a6027.tar.xz |
add linting (and some initial fixes)
Diffstat (limited to 'node_modules/private')
-rw-r--r-- | node_modules/private/LICENSE | 20 | ||||
-rw-r--r-- | node_modules/private/README.md | 246 | ||||
-rw-r--r-- | node_modules/private/package.json | 39 | ||||
-rw-r--r-- | node_modules/private/private.js | 129 |
4 files changed, 434 insertions, 0 deletions
diff --git a/node_modules/private/LICENSE b/node_modules/private/LICENSE new file mode 100644 index 000000000..6c2f144b1 --- /dev/null +++ b/node_modules/private/LICENSE @@ -0,0 +1,20 @@ +Copyright (c) 2014 Ben Newman <bn@cs.stanford.edu> + +Permission is hereby granted, free of charge, to any person obtaining +a copy of this software and associated documentation files (the +"Software"), to deal in the Software without restriction, including +without limitation the rights to use, copy, modify, merge, publish, +distribute, sublicense, and/or sell copies of the Software, and to +permit persons to whom the Software is furnished to do so, subject to +the following conditions: + +The above copyright notice and this permission notice shall be +included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. +IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, +TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE +SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. diff --git a/node_modules/private/README.md b/node_modules/private/README.md new file mode 100644 index 000000000..a8990aa6e --- /dev/null +++ b/node_modules/private/README.md @@ -0,0 +1,246 @@ +private [![Build Status](https://travis-ci.org/benjamn/private.png?branch=master)](https://travis-ci.org/benjamn/private) +=== + +A general-purpose utility for associating truly private state with any JavaScript object. + +Installation +--- + +From NPM: + + npm install private + +From GitHub: + + cd path/to/node_modules + git clone git://github.com/benjamn/private.git + cd private + npm install . + +Usage +--- +**Get or create a secret object associated with any (non-frozen) object:** +```js +var getSecret = require("private").makeAccessor(); +var obj = Object.create(null); // any kind of object works +getSecret(obj).totallySafeProperty = "p455w0rd"; + +console.log(Object.keys(obj)); // [] +console.log(Object.getOwnPropertyNames(obj)); // [] +console.log(getSecret(obj)); // { totallySafeProperty: "p455w0rd" } +``` +Now, only code that has a reference to both `getSecret` and `obj` can possibly access `.totallySafeProperty`. + +*Importantly, no global references to the secret object are retained by the `private` package, so as soon as `obj` gets garbage collected, the secret will be reclaimed as well. In other words, you don't have to worry about memory leaks.* + +**Create a unique property name that cannot be enumerated or guessed:** +```js +var secretKey = require("private").makeUniqueKey(); +var obj = Object.create(null); // any kind of object works + +Object.defineProperty(obj, secretKey, { + value: { totallySafeProperty: "p455w0rd" }, + enumerable: false // optional; non-enumerability is the default +}); + +Object.defineProperty(obj, "nonEnumerableProperty", { + value: "anyone can guess my name", + enumerable: false +}); + +console.log(obj[secretKey].totallySafeProperty); // p455w0rd +console.log(obj.nonEnumerableProperty); // "anyone can guess my name" +console.log(Object.keys(obj)); // [] +console.log(Object.getOwnPropertyNames(obj)); // ["nonEnumerableProperty"] + +for (var key in obj) { + console.log(key); // never called +} +``` +Because these keys are non-enumerable, you can't discover them using a `for`-`in` loop. Because `secretKey` is a long string of random characters, you would have a lot of trouble guessing it. And because the `private` module wraps `Object.getOwnPropertyNames` to exclude the keys it generates, you can't even use that interface to discover it. + +Unless you have access to the value of the `secretKey` property name, there is no way to access the value associated with it. So your only responsibility as secret-keeper is to avoid handing out the value of `secretKey` to untrusted code. + +Think of this style as a home-grown version of the first style. Note, however, that it requires a full implementation of ES5's `Object.defineProperty` method in order to make any safety guarantees, whereas the first example will provide safety even in environments that do not support `Object.defineProperty`. + +Rationale +--- + +In JavaScript, the only data that are truly private are local variables +whose values do not *leak* from the scope in which they were defined. + +This notion of *closure privacy* is powerful, and it readily provides some +of the benefits of traditional data privacy, a la Java or C++: +```js +function MyClass(secret) { + this.increment = function() { + return ++secret; + }; +} + +var mc = new MyClass(3); +console.log(mc.increment()); // 4 +``` +You can learn something about `secret` by calling `.increment()`, and you +can increase its value by one as many times as you like, but you can never +decrease its value, because it is completely inaccessible except through +the `.increment` method. And if the `.increment` method were not +available, it would be as if no `secret` variable had ever been declared, +as far as you could tell. + +This style breaks down as soon as you want to inherit methods from the +prototype of a class: +```js +function MyClass(secret) { + this.secret = secret; +} + +MyClass.prototype.increment = function() { + return ++this.secret; +}; +``` +The only way to communicate between the `MyClass` constructor and the +`.increment` method in this example is to manipulate shared properties of +`this`. Unfortunately `this.secret` is now exposed to unlicensed +modification: +```js +var mc = new MyClass(6); +console.log(mc.increment()); // 7 +mc.secret -= Infinity; +console.log(mc.increment()); // -Infinity +mc.secret = "Go home JavaScript, you're drunk."; +mc.increment(); // NaN +``` +Another problem with closure privacy is that it only lends itself to +per-instance privacy, whereas the `private` keyword in most +object-oriented languages indicates that the data member in question is +visible to all instances of the same class. + +Suppose you have a `Node` class with a notion of parents and children: +```js +function Node() { + var parent; + var children = []; + + this.getParent = function() { + return parent; + }; + + this.appendChild = function(child) { + children.push(child); + child.parent = this; // Can this be made to work? + }; +} +``` +The desire here is to allow other `Node` objects to manipulate the value +returned by `.getParent()`, but otherwise disallow any modification of the +`parent` variable. You could expose a `.setParent` function, but then +anyone could call it, and you might as well give up on the getter/setter +pattern. + +This module solves both of these problems. + +Usage +--- + +Let's revisit the `Node` example from above: +```js +var p = require("private").makeAccessor(); + +function Node() { + var privates = p(this); + var children = []; + + this.getParent = function() { + return privates.parent; + }; + + this.appendChild = function(child) { + children.push(child); + var cp = p(child); + if (cp.parent) + cp.parent.removeChild(child); + cp.parent = this; + return child; + }; +} +``` +Now, in order to access the private data of a `Node` object, you need to +have access to the unique `p` function that is being used here. This is +already an improvement over the previous example, because it allows +restricted access by other `Node` instances, but can it help with the +`Node.prototype` problem too? + +Yes it can! +```js +var p = require("private").makeAccessor(); + +function Node() { + p(this).children = []; +} + +var Np = Node.prototype; + +Np.getParent = function() { + return p(this).parent; +}; + +Np.appendChild = function(child) { + p(this).children.push(child); + var cp = p(child); + if (cp.parent) + cp.parent.removeChild(child); + cp.parent = this; + return child; +}; +``` +Because `p` is in scope not only within the `Node` constructor but also +within `Node` methods, we can finally avoid redefining methods every time +the `Node` constructor is called. + +Now, you might be wondering how you can restrict access to `p` so that no +untrusted code is able to call it. The answer is to use your favorite +module pattern, be it CommonJS, AMD `define`, or even the old +Immediately-Invoked Function Expression: +```js +var Node = (function() { + var p = require("private").makeAccessor(); + + function Node() { + p(this).children = []; + } + + var Np = Node.prototype; + + Np.getParent = function() { + return p(this).parent; + }; + + Np.appendChild = function(child) { + p(this).children.push(child); + var cp = p(child); + if (cp.parent) + cp.parent.removeChild(child); + cp.parent = this; + return child; + }; + + return Node; +}()); + +var parent = new Node; +var child = new Node; +parent.appendChild(child); +assert.strictEqual(child.getParent(), parent); +``` +Because this version of `p` never leaks from the enclosing function scope, +only `Node` objects have access to it. + +So, you see, the claim I made at the beginning of this README remains +true: + +> In JavaScript, the only data that are truly private are local variables +> whose values do not *leak* from the scope in which they were defined. + +It just so happens that closure privacy is sufficient to implement a +privacy model similar to that provided by other languages. diff --git a/node_modules/private/package.json b/node_modules/private/package.json new file mode 100644 index 000000000..c1c520b32 --- /dev/null +++ b/node_modules/private/package.json @@ -0,0 +1,39 @@ +{ + "author": { + "name": "Ben Newman", + "email": "bn@cs.stanford.edu" + }, + "name": "private", + "description": "Utility for associating truly private state with any JavaScript object", + "keywords": [ + "private", + "access control", + "access modifiers", + "encapsulation", + "secret", + "state", + "privilege", + "scope", + "es5" + ], + "version": "0.1.7", + "homepage": "http://github.com/benjamn/private", + "repository": { + "type": "git", + "url": "git://github.com/benjamn/private.git" + }, + "license": "MIT", + "main": "private.js", + "files": [ + "private.js" + ], + "scripts": { + "test": "mocha --reporter spec --full-trace test/run.js" + }, + "engines": { + "node": ">= 0.6" + }, + "devDependencies": { + "mocha": "^3.2.0" + } +} diff --git a/node_modules/private/private.js b/node_modules/private/private.js new file mode 100644 index 000000000..4f952fc48 --- /dev/null +++ b/node_modules/private/private.js @@ -0,0 +1,129 @@ +"use strict"; + +var originalObject = Object; +var originalDefProp = Object.defineProperty; +var originalCreate = Object.create; + +function defProp(obj, name, value) { + if (originalDefProp) try { + originalDefProp.call(originalObject, obj, name, { value: value }); + } catch (definePropertyIsBrokenInIE8) { + obj[name] = value; + } else { + obj[name] = value; + } +} + +// For functions that will be invoked using .call or .apply, we need to +// define those methods on the function objects themselves, rather than +// inheriting them from Function.prototype, so that a malicious or clumsy +// third party cannot interfere with the functionality of this module by +// redefining Function.prototype.call or .apply. +function makeSafeToCall(fun) { + if (fun) { + defProp(fun, "call", fun.call); + defProp(fun, "apply", fun.apply); + } + return fun; +} + +makeSafeToCall(originalDefProp); +makeSafeToCall(originalCreate); + +var hasOwn = makeSafeToCall(Object.prototype.hasOwnProperty); +var numToStr = makeSafeToCall(Number.prototype.toString); +var strSlice = makeSafeToCall(String.prototype.slice); + +var cloner = function(){}; +function create(prototype) { + if (originalCreate) { + return originalCreate.call(originalObject, prototype); + } + cloner.prototype = prototype || null; + return new cloner; +} + +var rand = Math.random; +var uniqueKeys = create(null); + +function makeUniqueKey() { + // Collisions are highly unlikely, but this module is in the business of + // making guarantees rather than safe bets. + do var uniqueKey = internString(strSlice.call(numToStr.call(rand(), 36), 2)); + while (hasOwn.call(uniqueKeys, uniqueKey)); + return uniqueKeys[uniqueKey] = uniqueKey; +} + +function internString(str) { + var obj = {}; + obj[str] = true; + return Object.keys(obj)[0]; +} + +// External users might find this function useful, but it is not necessary +// for the typical use of this module. +exports.makeUniqueKey = makeUniqueKey; + +// Object.getOwnPropertyNames is the only way to enumerate non-enumerable +// properties, so if we wrap it to ignore our secret keys, there should be +// no way (except guessing) to access those properties. +var originalGetOPNs = Object.getOwnPropertyNames; +Object.getOwnPropertyNames = function getOwnPropertyNames(object) { + for (var names = originalGetOPNs(object), + src = 0, + dst = 0, + len = names.length; + src < len; + ++src) { + if (!hasOwn.call(uniqueKeys, names[src])) { + if (src > dst) { + names[dst] = names[src]; + } + ++dst; + } + } + names.length = dst; + return names; +}; + +function defaultCreatorFn(object) { + return create(null); +} + +function makeAccessor(secretCreatorFn) { + var brand = makeUniqueKey(); + var passkey = create(null); + + secretCreatorFn = secretCreatorFn || defaultCreatorFn; + + function register(object) { + var secret; // Created lazily. + + function vault(key, forget) { + // Only code that has access to the passkey can retrieve (or forget) + // the secret object. + if (key === passkey) { + return forget + ? secret = null + : secret || (secret = secretCreatorFn(object)); + } + } + + defProp(object, brand, vault); + } + + function accessor(object) { + if (!hasOwn.call(object, brand)) + register(object); + return object[brand](passkey); + } + + accessor.forget = function(object) { + if (hasOwn.call(object, brand)) + object[brand](passkey, true); + }; + + return accessor; +} + +exports.makeAccessor = makeAccessor; |