hellojs-xiaotian/assets/knockout/src/binding/bindingProvider.js

A clientside Javascript library for standardizing requests to OAuth2 web services (and OAuth1 - with a shim)

(function() {
    var defaultBindingAttributeName = "data-bind";

    ko.bindingProvider = function() {
        this.bindingCache = {};
    };

    ko.utils.extend(ko.bindingProvider.prototype, {
        'nodeHasBindings': function(node) {
            switch (node.nodeType) {
                case 1: // Element
                    return node.getAttribute(defaultBindingAttributeName) != null
                        || ko.components['getComponentNameForNode'](node);
                case 8: // Comment node
                    return ko.virtualElements.hasBindingValue(node);
                default: return false;
            }
        },

        'getBindings': function(node, bindingContext) {
            var bindingsString = this['getBindingsString'](node, bindingContext),
                parsedBindings = bindingsString ? this['parseBindingsString'](bindingsString, bindingContext, node) : null;
            return ko.components.addBindingsForCustomElement(parsedBindings, node, bindingContext, /* valueAccessors */ false);
        },

        'getBindingAccessors': function(node, bindingContext) {
            var bindingsString = this['getBindingsString'](node, bindingContext),
                parsedBindings = bindingsString ? this['parseBindingsString'](bindingsString, bindingContext, node, { 'valueAccessors': true }) : null;
            return ko.components.addBindingsForCustomElement(parsedBindings, node, bindingContext, /* valueAccessors */ true);
        },

        // The following function is only used internally by this default provider.
        // It's not part of the interface definition for a general binding provider.
        'getBindingsString': function(node, bindingContext) {
            switch (node.nodeType) {
                case 1: return node.getAttribute(defaultBindingAttributeName);   // Element
                case 8: return ko.virtualElements.virtualNodeBindingValue(node); // Comment node
                default: return null;
            }
        },

        // The following function is only used internally by this default provider.
        // It's not part of the interface definition for a general binding provider.
        'parseBindingsString': function(bindingsString, bindingContext, node, options) {
            try {
                var bindingFunction = createBindingsStringEvaluatorViaCache(bindingsString, this.bindingCache, options);
                return bindingFunction(bindingContext, node);
            } catch (ex) {
                ex.message = "Unable to parse bindings.\nBindings value: " + bindingsString + "\nMessage: " + ex.message;
                throw ex;
            }
        }
    });

    ko.bindingProvider['instance'] = new ko.bindingProvider();

    function createBindingsStringEvaluatorViaCache(bindingsString, cache, options) {
        var cacheKey = bindingsString + (options && options['valueAccessors'] || '');
        return cache[cacheKey]
            || (cache[cacheKey] = createBindingsStringEvaluator(bindingsString, options));
    }

    function createBindingsStringEvaluator(bindingsString, options) {
        // Build the source for a function that evaluates "expression"
        // For each scope variable, add an extra level of "with" nesting
        // Example result: with(sc1) { with(sc0) { return (expression) } }
        var rewrittenBindings = ko.expressionRewriting.preProcessBindings(bindingsString, options),
            functionBody = "with($context){with($data||{}){return{" + rewrittenBindings + "}}}";
        return new Function("$context", "$element", functionBody);
    }
})();

ko.exportSymbol('bindingProvider', ko.bindingProvider);