xqlint/lib/parsers/JSONParseTreeHandler.js

XQuery & JSONiq Quality Checker

exports.JSONParseTreeHandler = function (code) {
	'use strict';

    //List of Nodes to be indexed
    var toBeIndex = ['VarDecl', 'FunctionDecl'];
    
    //List of nodes that are not targeted by the parse tree size optimization.
    var list = [
        'OrExpr', 'AndExpr', 'ComparisonExpr', 'StringConcatExpr', 'RangeExpr',
        'AdditiveExpr', 'MultiplicativeExpr',
        'UnionExpr', 'IntersectExceptExpr', 'InstanceofExpr', 'TreatExpr', 'CastableExpr', 'CastExpr', 'UnaryExpr', 'ValueExpr',
        'FTContainsExpr', 'SimpleMapExpr', 'PathExpr', 'RelativePathExpr', 'PostfixExpr', 'StepExpr'
    ];

    var ast = null;
    var ptr = null;
    var remains = code;
    var cursor = 0;
    var lineCursor = 0;
    var line = 0;
    //var col = 0;

    function createNode(name) {
        return {
            name: name,
            children: [],
            getParent: null,
            pos: {
                sl: 0,
                sc: 0,
                el: 0,
                ec: 0
            }
        };
    }

    function setValue(node, begin, end) {

        var e = end - cursor;
        ptr.value = remains.substring(0, e);
        remains = remains.substring(e);
        cursor = end;

        var sl = line;
        var sc = lineCursor;
        var el = sl + ptr.value.split('\n').length - 1;
        var lastIdx = ptr.value.lastIndexOf('\n');
        var ec = lastIdx === -1 ? sc + ptr.value.length : ptr.value.substring(lastIdx + 1).length;
        //      ec = ec === 0 ? 0 : ec - 1;

        line = el;
        //lineCursor = ec === 0 ? 0 : ec;
        lineCursor = ec;

        ptr.pos.sl = sl;
        ptr.pos.sc = sc;
        ptr.pos.el = el;
        ptr.pos.ec = ec;
    }

    function pushNode(name) { //begin
        var node = createNode(name);
        if (ast === null) {
            ast = node;
            ast.index = [];
            ptr = node;
        } else {
            node.getParent = ptr;
            ptr.children.push(node);
            ptr = ptr.children[ptr.children.length - 1];
        }
    }

    function popNode() {

        if (ptr.children.length > 0) {
            var s = ptr.children[0];
            var e = null;
            //We want to skip empty non terminals. For instance:
            // [108] AxisStep ::= (ReverseStep | ForwardStep) PredicateList
            // [120] PredicateList ::= Predicate*
            for (var i = ptr.children.length - 1; i >= 0; i--) {
                e = ptr.children[i];
                if (e.pos.el !== 0 || e.pos.ec !== 0) {
                    break;
                }
            }
            ptr.pos.sl = s.pos.sl;
            ptr.pos.sc = s.pos.sc;
            ptr.pos.el = e.pos.el;
            ptr.pos.ec = e.pos.ec;
        }

        //Normalize EQName && FunctionName
        if (ptr.name === 'FunctionName') {
            ptr.name = 'EQName';
        }
        if (ptr.name === 'EQName' && ptr.value === undefined) {
            ptr.value = ptr.children[0].value;
            ptr.children.pop();
        }
    
        if(toBeIndex.indexOf(ptr.name) !== -1) {
            ast.index.push(ptr);
        }
    
        if (ptr.getParent !== null) {
            ptr = ptr.getParent;
            //for(var i in ptr.children) {
            //delete ptr.children[i].getParent;
            //}
        } else {
            //delete ptr.getParent;
        }

        //Parse tree size optimization
        if (ptr.children.length > 0) {
            var lastChild = ptr.children[ptr.children.length - 1];
            if (lastChild.children.length === 1 && list.indexOf(lastChild.name) !== -1) {
                ptr.children[ptr.children.length - 1] = lastChild.children[0];
            }
        }
    }

    this.closeParseTree = function () {
        while (ptr.getParent !== null) {
            popNode();
        }
        popNode();
    };

    this.peek = function () {
        return ptr;
    };

    this.getParseTree = function () {
        return ast;
    };

    this.reset = function () {}; //input

    this.startNonterminal = function (name, begin) {
        pushNode(name, begin);
    };

    this.endNonterminal = function () {//name, end
        popNode();
    };

    this.terminal = function (name, begin, end) {
        name = (name.substring(0, 1) === '\'' && name.substring(name.length - 1) === '\'') ? 'TOKEN' : name;
        pushNode(name, begin);
        setValue(ptr, begin, end);
        popNode();
    };

    this.whitespace = function (begin, end) {
        var name = 'WS';
        pushNode(name, begin);
        setValue(ptr, begin, end);
        popNode();
    };
};