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// ==========================================
// Copyright 2013 Twitter, Inc
// Licensed under The MIT License
// ==========================================
"use strict";
define(
[
'./utils',
'../tools/debug/debug'
],
function(util, debug) {
//enumerables are shims - getOwnPropertyDescriptor shim doesn't work
var canWriteProtect = debug.enabled && !util.isEnumerable(Object, 'getOwnPropertyDescriptor');
//whitelist of unlockable property names
var dontLock = ['mixedIn'];
if (canWriteProtect) {
//IE8 getOwnPropertyDescriptor is built-in but throws exeption on non DOM objects
try {
Object.getOwnPropertyDescriptor(Object, 'keys');
} catch(e) {
canWriteProtect = false;
}
}
function setPropertyWritability(obj, isWritable) {
if (!canWriteProtect) {
return;
}
var props = Object.create(null);
Object.keys(obj).forEach(
function (key) {
if (dontLock.indexOf(key) < 0) {
var desc = Object.getOwnPropertyDescriptor(obj, key);
desc.writable = isWritable;
props[key] = desc;
}
}
);
Object.defineProperties(obj, props);
}
function unlockProperty(obj, prop, op) {
var writable;
if (!canWriteProtect || !obj.hasOwnProperty(prop)) {
op.call(obj);
return;
}
writable = Object.getOwnPropertyDescriptor(obj, prop).writable;
Object.defineProperty(obj, prop, { writable: true });
op.call(obj);
Object.defineProperty(obj, prop, { writable: writable });
}
function mixin(base, mixins) {
base.mixedIn = base.hasOwnProperty('mixedIn') ? base.mixedIn : [];
mixins.forEach(function(mixin) {
if (base.mixedIn.indexOf(mixin) == -1) {
setPropertyWritability(base, false);
mixin.call(base);
base.mixedIn.push(mixin);
}
});
setPropertyWritability(base, true);
}
return {
mixin: mixin,
unlockProperty: unlockProperty
};
}
);