Added VisibilityObjectFactoryFactory (#25)

- This may be temporary, depending on the ultimate implementation. This is intended to ease into the refactoring.

lib/VisibilityObjectFactoryFactory.js

@@ -0,0 +1,53 @@
+/**
+ * Contains factory for 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 core
+ */
+
+// XXX: Tightly coupled
+var util = require( __dirname + '/util' ),
+
+    VisibilityObjectFactory = require( __dirname + '/VisibilityObjectFactory' ),
+
+    FallbackVisibilityObjectFactory =
+        require( __dirname + '/FallbackVisibilityObjectFactory' )
+;
+
+
+/**
+ * Responsible for instantiating the VisibilityObjectFactory appropriate for the
+ * runtime environment
+ *
+ * This prototype determines what class should be instantiated. If we are within
+ * an ECMAScript 5 environment, we can take full advantage of the standard
+ * visibility object implementation. Otherwise, we are unable to emulate proxies
+ * and must fall back on a less sophisticated implementation that sacrifices
+ * visibility support.
+ */
+exports.fromEnvironment = function()
+{
+    // if falling back, return fallback, otherwise standard
+    return ( util.definePropertyFallback() )
+        ? FallbackVisibilityObjectFactory()
+        : VisibilityObjectFactory()
+    ;
+};
+

test/VisibilityObjectFactoryFactoryTest.js

@@ -0,0 +1,78 @@
+/**
+ * Tests factory for 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' ),
+    util   = common.require( 'util' ),
+
+    sut = common.require( 'VisibilityObjectFactoryFactory' ),
+
+    VisibilityObjectFactory = common.require( 'VisibilityObjectFactory' ),
+
+    FallbackVisibilityObjectFactory =
+        common.require( 'FallbackVisibilityObjectFactory' )
+;
+
+
+/**
+ * By default, if supported by our environment, we should use the standard
+ * factory to provide proper visibility support.
+ */
+( function testReturnsStandardIfNotFallingBack()
+{
+    // don't bother with the test if we don't support the standard visibility
+    // object
+    if ( util.definePropertyFallback() )
+    {
+        return;
+    }
+
+    assert.ok(
+        ( sut.fromEnvironment() instanceof VisibilityObjectFactory ),
+        "Creates standard VisibilityObjectFactory if supported"
+    );
+} )();
+
+
+/**
+ * If not supported by our environment, we should be permitted to fall back to a
+ * working implementation that sacrifices visibility support.
+ */
+( function testReturnsFallbackFactoryIfFallingBack()
+{
+    var old = util.definePropertyFallback();
+
+    // force fallback
+    util.definePropertyFallback( true );
+
+    assert.ok(
+        ( sut.fromEnvironment() instanceof FallbackVisibilityObjectFactory ),
+        "Creates fallback VisibilityObjectFactory if falling back"
+    );
+
+    // restore fallback
+    util.definePropertyFallback( old );
+} )();
+