MeshAgent/modules/parseXml.js

/*
Copyright 2018 - 2019 Intel Corporation

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

try { Object.defineProperty(Array.prototype, "peek", { value: function () { return (this.length > 0 ? this[this.length - 1] : undefined); } }); } catch (e) { }



function _treeBuilder()
{
    this.tree = [];

    this.push = function (element)
    {
        this.tree.push(element);
    };
    this.pop = function ()
    {
        var element = this.tree.pop();
        if(this.tree.length>0)
        {
            this.tree.peek().childNodes.push(element);
        }
        return (element);
    };
    this.peek = function()
    {
        return (this.tree.peek());
    }
    this.addNamespace = function(prefix, namespace)
    {
        this.tree.peek().nsTable[prefix] = namespace;
        if(this.tree.peek().attributes.length > 0)
        {
            for(var i = 0; i<this.tree.peek().attributes; ++i)
            {
                var a = this.tree.peek().attributes[i];
                if(prefix == '*' && a.name == a.localName)
                {
                    a.namespace = namespace;
                }
                else if(prefix != '*' && a.name != a.localName)
                {
                    var pfx = a.name.split(':')[0];
                    if(pfx == prefix)
                    {
                        a.namespace = namespace;
                    }
                }
            }
        }
    }
    this.getNamespace = function(prefix)
    {
        for(var i=this.tree.length-1;i>=0;--i)
        {
            if(this.tree[i].nsTable[prefix] != undefined)
            {
                return (this.tree[i].nsTable[prefix]);
            }
        }
        return ('undefined');
    }
}


// This is a drop-in replacement to _turnToXml() that works without xml parser dependency.
function _turnToXml(text)
{
    if (text == null) return null;
    return ({ childNodes: [_turnToXmlRec(text)], getElementsByTagName: _getElementsByTagName, getChildElementsByTagName: _getChildElementsByTagName, getElementsByTagNameNS: _getElementsByTagNameNS });
}

function _getElementsByTagNameNS(ns, name)
{
    var ret = []; _xmlTraverseAllRec(this.childNodes, function (node)
    {
        if (node.localName == name && (node.namespace == ns || ns == '*')) { ret.push(node); }
    }); return ret;
}
function _getElementsByTagName(name)
{
    var ret = []; _xmlTraverseAllRec(this.childNodes, function (node)
    {
        if (node.localName == name) { ret.push(node); }
    }); return ret;
}
function _getChildElementsByTagName(name)
{
    var ret = [];
    if (this.childNodes != undefined)
    {
        for (var node in this.childNodes) {
            if (this.childNodes[node].localName == name) { ret.push(this.childNodes[node]); }
        }
    }
    return (ret);
}
function _getChildElementsByTagNameNS(ns, name)
{
    var ret = [];
    if (this.childNodes != undefined)
    {
        for (var node in this.childNodes)
        {
            if (this.childNodes[node].localName == name && (ns == '*' || this.childNodes[node].namespace == ns)) { ret.push(this.childNodes[node]); }
        }
    }
    return (ret);
}

function _xmlTraverseAllRec(nodes, func) { for (var i in nodes) { func(nodes[i]); if (nodes[i].childNodes) { _xmlTraverseAllRec(nodes[i].childNodes, func); } } }
function _turnToXmlRec(text)
{
    var elementStack =  new _treeBuilder();
    var lastElement = null;

    var x1 = text.split('<'), ret = [], element = null, currentElementName = null;
    for (var i in x1)
    {
        var x2 = x1[i].split('>'), x3 = x2[0].split(' '), elementName = x3[0];
        if ((elementName.length > 0) && (elementName[0] != '?'))
        {
            if (elementName[0] != '/')
            {
                var localName;
                var localname2 = elementName.split(' ')[0].split(':'), localName = (localname2.length > 1) ? localname2[1] : localname2[0];
                var attributes = [];
                Object.defineProperty(attributes, "get",
                {
                    value: function ()
                    {
                        if (arguments.length == 1)
                        {
                            for (var a in this) { if (this[a].name == arguments[0]) { return (this[a]); } }
                        }
                        else if (arguments.length == 2)
                        {
                            for (var a in this) { if (this[a].name == arguments[1] && (arguments[0] == '*' || this[a].namespace == arguments[0])) { return (this[a]); } }
                        }
                        else
                        {
                            throw ('attributes.get(): Invalid number of parameters');
                        }
                    }
                });


                elementStack.push({ name: elementName, localName: localName, getChildElementsByTagName: _getChildElementsByTagName, getElementsByTagNameNS: _getElementsByTagNameNS, getChildElementsByTagNameNS: _getChildElementsByTagNameNS, attributes: attributes, childNodes: [], nsTable: {} });

                // Parse Attributes
                if (x3.length > 0)
                {
                    var skip = false;
                    for (var j in x3)
                    {
                        if (x3[j] == '/')  
                        {
                            // This is an empty Element
                            elementStack.peek().namespace = elementStack.peek().name == elementStack.peek().localName ? elementStack.getNamespace('*') : elementStack.getNamespace(elementStack.peek().name.substring(0, elementStack.peek().name.indexOf(':')));
                            elementStack.peek().textContent = '';
                            lastElement = elementStack.pop();
                            skip = true;
                            break;
                        }
                        var k = x3[j].indexOf('=');
                        if (k > 0)
                        {
                            var attrName = x3[j].substring(0, k);
                            var attrValue = x3[j].substring(k + 2, x3[j].length - 1);
                            var attrNS = elementStack.getNamespace('*');

                            if (attrName == 'xmlns')
                            {
                                elementStack.addNamespace('*', attrValue);
                                attrNS = attrValue;
                            }
                            else if (attrName.startsWith('xmlns:'))
                            {
                                elementStack.addNamespace(attrName.substring(6), attrValue);
                            }
                            else
                            {
                                var ax = attrName.split(':');
                                if (ax.length == 2) { attrName = ax[1]; attrNS = elementStack.getNamespace(ax[0]); }
                            }
                            elementStack.peek().attributes.push({ name: attrName, value: attrValue, namespace: attrNS });
                        }
                    }
                    if (skip) { continue; }
                }
                elementStack.peek().namespace = elementStack.peek().name == elementStack.peek().localName ? elementStack.getNamespace('*') : elementStack.getNamespace(elementStack.peek().name.substring(0, elementStack.peek().name.indexOf(':')));
                if (x2[1]) { elementStack.peek().textContent = x2[1]; }
            }
            else
            {
                lastElement = elementStack.pop();
            }                 
        }
    }
    return lastElement;
}

module.exports = _turnToXml;