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Implemented FallbackVisibilityObjectFactory (#25)

closure/master
Mike Gerwitz 2011-08-13 21:33:20 -04:00
parent cd1f8921de
commit 567c9f59a0
3 changed files with 173 additions and 1 deletions

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@ -22,3 +22,62 @@
* @package core * @package core
*/ */
/**
* Initializes fallback visibility object factory
*
* Unlike the standard visibility object, fallback does not create various
* layers. This is for the simple fact that setting a value on one of the layers
* is not visible to layers beneath it (its prototypes). Fallback is necessary
* if proxy support or emulation (via ES5 getters/setters) is unavailable.
*/
module.exports = exports = function FallbackVisibilityObjectFactory()
{
// permit omitting 'new' keyword
if ( !( this instanceof exports ) )
{
return new exports();
}
};
/**
* "Inherit" from VisibilityObjectFactory
*/
exports.prototype = require( __dirname + '/VisibilityObjectFactory' )();
/**
* Do not create private visibility layer
*
* We're likely falling back because we cannot properly support the private
* visibility layer. Therefore, it will be omitted.
*
* @param {Object} atop_of will be returned, unmodified
* @param {Object} properties ignored
*
* @return {Object} provided object with no additional layer
*/
exports.prototype._createPrivateLayer = function( atop_of, properties )
{
return atop_of;
};
/**
* Does not create property proxy
*
* The fallback implementation is used because proxies are not supported and
* cannot be emulated with getters/setters.
*
* @param {Object} base will be returned, unmodified
* @param {Object} dest ignored
* @param {Object} props ignored
*
* @return {Object} given base
*/
exports.prototype.createPropProxy = function( base, dest, props )
{
return base;
};

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@ -96,6 +96,7 @@ exports.prototype.setup = function setup( dest, properties, methods )
* visibility object (e.g. to prevent it from being created). * visibility object (e.g. to prevent it from being created).
* *
* @param {Object} atop_of object to add private layer atop of * @param {Object} atop_of object to add private layer atop of
* @param {Object} properties properties
* *
* @return {Object} private layer with given object as prototype * @return {Object} private layer with given object as prototype
*/ */

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@ -0,0 +1,112 @@
/**
* Tests fallback visibility object factory
*
* Copyright (C) 2010 Mike Gerwitz
*
* This file is part of ease.js.
*
* ease.js is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* @author Mike Gerwitz
* @package test
*/
var common = require( './common' ),
assert = require( 'assert' ),
// SUT
FallbackVisibilityObjectFactory =
common.require( 'FallbackVisibilityObjectFactory' ),
// parent of SUT
VisibilityObjectFactory = common.require( 'VisibilityObjectFactory' ),
sut = FallbackVisibilityObjectFactory(),
props = methods = {
'public': {},
'protected': {},
'private': {},
}
;
/**
* To keep with the spirit of ease.js, we should be able to instantiate
* VisibilityObjectFactory both with and without the 'new' keyword
*
* Consistency is key with these sorts of things.
*/
( function testCanInstantiateWithAndWithoutNewKeyword()
{
// with 'new' keyword
assert.ok(
( new FallbackVisibilityObjectFactory() )
instanceof FallbackVisibilityObjectFactory,
"Should be able to instantiate FallbackVisibilityObjectFactory with " +
"'new' keyword"
);
// without 'new' keyword
assert.ok(
FallbackVisibilityObjectFactory()
instanceof FallbackVisibilityObjectFactory,
"Should be able to instantiate FallbackVisibilityObjectFactory " +
"without 'new' keyword"
);
} )();
/**
* VisibilityObjectFactory should be part of our prototype chain.
*/
( function testInheritsFromVisibilityObjectFactory()
{
// check an instance, rather than __proto__, because older engines do not
// support it
assert.ok(
FallbackVisibilityObjectFactory() instanceof VisibilityObjectFactory,
"Fallback should inherit from VisibilityObjectFactory"
);
} )();
/**
* We're falling back because we do not support the private visibility layer (or
* any layers, for that matter). Ensure it's not created.
*/
( function testSetupMethodShouldNotAddPrivateLayer()
{
var dest = {},
obj = sut.setup( dest, props, methods );
assert.strictEqual( dest, obj,
"Private visibility layer is not added atop destination"
);
} )();
( function testCreatingPropertyProxyShouldSimplyReturnSelf()
{
var base = {},
dest = {};
assert.strictEqual(
sut.createPropProxy( base, dest, props ),
base,
"Creating property proxy should simply return original object"
);
} )();