player/js/utils/expressions/Expressions.js

var Expressions = (function(){
    var ob = {};
    ob.initExpressions = initExpressions;


    function initExpressions(animation){

        var stackCount = 0;
        var registers = [];

        function pushExpression() {
            stackCount += 1;
        }

        function popExpression() {
            stackCount -= 1;
            if (stackCount === 0) {
                releaseInstances();
            }
        }

        function registerExpressionProperty(expression) {
            if (registers.indexOf(expression) === -1) {
                registers.push(expression)
            }
        }

        function releaseInstances() {
            var i, len = registers.length;
            for (i = 0; i < len; i += 1) {
                registers[i].release();
            }
            registers.length = 0;
        }

        animation.renderer.compInterface = CompExpressionInterface(animation.renderer);
        animation.renderer.globalData.projectInterface.registerComposition(animation.renderer);
        animation.renderer.globalData.pushExpression = pushExpression;
        animation.renderer.globalData.popExpression = popExpression;
        animation.renderer.globalData.registerExpressionProperty = registerExpressionProperty;
    }
   return ob;
}());

expressionsPlugin = Expressions;