source: Dev/trunk/src/client/dojox/jsonPath/query.js

dojo.provide("dojox.jsonPath.query");

dojox.jsonPath.query = function(/*Object*/ obj, /*String*/ expr, /*Object*/ arg){
        // summary:
        //              Perform jsonPath query `expr` on javascript object or json string `obj`
        // obj:
        //              object || json string to perform query on
        // expr:
        //              jsonPath expression (string) to be evaluated
        // arg:
        //              {} special arguments.
        //
        //              - resultType: "VALUE"||"BOTH"||"PATH"} (defaults to value)
        //              - evalType: "RESULT"||"ITEM"} (defaults to ?)

        var re = dojox.jsonPath._regularExpressions;
        if (!arg){arg={};}

        var strs = [];
        function _str(i){ return strs[i];}
        var _strName = _str.name;
        var acc;
        if (arg.resultType == "PATH" && arg.evalType == "RESULT") throw Error("RESULT based evaluation not supported with PATH based results");
        var P = {
                resultType: arg.resultType || "VALUE",
                normalize: function(expr){
                        var subx = [];
                        expr = expr.replace(/'([^']|'')*'/g, function(t){return _strName + "("+(strs.push(eval(t))-1)+")";});
                        var ll = -1;
                        while(ll!=subx.length){
                                ll=subx.length;//TODO: Do expression syntax checking
                                expr = expr.replace(/(\??\([^\(\)]*\))/g, function($0){return "#"+(subx.push($0)-1);});
                        }
                        expr = expr.replace(/[\['](#[0-9]+)[\]']/g,'[$1]')
                                                  .replace(/'?\.'?|\['?/g, ";")
                                                  .replace(/;;;|;;/g, ";..;")
                                                  .replace(/;$|'?\]|'$/g, "");
                        ll = -1;
                        while(ll!=expr){
                                ll=expr;
                                         expr = expr.replace(/#([0-9]+)/g, function($0,$1){return subx[$1];});
                        }
                        return expr.split(";");
                },
                asPaths: function(paths){
                        for (var j=0;j<paths.length;j++){
                        var p = "$";
                        var x= paths[j];
                        for (var i=1,n=x.length; i<n; i++)
                                p += /^[0-9*]+$/.test(x[i]) ? ("["+x[i]+"]") : ("['"+x[i]+"']");
                        paths[j]=p;
                  }
                        return paths;
                },
                exec: function(locs, val, rb){
                        var path = ['$'];
                        var result=rb?val:[val];
                        var paths=[path];
                        function add(v, p,def){
                          if (v && v.hasOwnProperty(p) && P.resultType != "VALUE") paths.push(path.concat([p]));
                                if (def)
                                  result = v[p];
                          else if (v && v.hasOwnProperty(p))
                                        result.push(v[p]);
                        }
                        function desc(v){
                                result.push(v);
                                paths.push(path);
                                P.walk(v,function(i){
                                        if (typeof v[i] ==='object')  {
                                                var oldPath = path;
                                                path = path.concat(i);
                                                desc(v[i]);
                                                path = oldPath;
                                        }
                                });
                        }
                        function slice(loc, val){
                                if (val instanceof Array){
                                        var len=val.length, start=0, end=len, step=1;
                                        loc.replace(/^(-?[0-9]*):(-?[0-9]*):?(-?[0-9]*)$/g, function($0,$1,$2,$3){start=parseInt($1||start);end=parseInt($2||end);step=parseInt($3||step);});
                                        start = (start < 0) ? Math.max(0,start+len) : Math.min(len,start);
                                        end = (end < 0) ? Math.max(0,end+len) : Math.min(len,end);
                                        for (var i=start; i<end; i+=step)
                                                add(val,i);
                                }
                        }
                        function repStr(str){
                                var i=loc.match(/^_str\(([0-9]+)\)$/);
                                return i?strs[i[1]]:str;
                        }
                        function oper(val){
                                if (/^\(.*?\)$/.test(loc)) // [(expr)]
                                        add(val, P.eval(loc, val),rb);
                                else if (loc === "*"){
                                        P.walk(val, rb && val instanceof Array ? // if it is result based, there is no point to just return the same array
                                        function(i){P.walk(val[i],function(j){ add(val[i],j); })} :
                                        function(i){ add(val,i); });
                                }
                                else if (loc === "..")
                                        desc(val);
                                else if (/,/.test(loc)){ // [name1,name2,...]
                                        for (var s=loc.split(/'?,'?/),i=0,n=s.length; i<n; i++)
                                                add(val,repStr(s[i]));
                                }
                                else if (/^\?\(.*?\)$/.test(loc)) // [?(expr)]
                                        P.walk(val, function(i){ if (P.eval(loc.replace(/^\?\((.*?)\)$/,"$1"),val[i])) add(val,i); });
                                else if (/^(-?[0-9]*):(-?[0-9]*):?([0-9]*)$/.test(loc)) // [start:end:step]  python slice syntax
                                        slice(loc, val);
                                else {
                                        loc=repStr(loc);
                                        if (rb && val instanceof Array && !/^[0-9*]+$/.test(loc))
                                                P.walk(val, function(i){ add(val[i], loc)});
                                        else
                                                add(val,loc,rb);
                                }

                        }
                        while (locs.length){
                                var loc = locs.shift();
                                if ((val = result) === null || val===undefined) return val;
                                result = [];
                                var valPaths = paths;
                                paths = [];
                                if (rb)
                                        oper(val)
                                else
                                        P.walk(val,function(i){path=valPaths[i]||path;oper(val[i])});
                        }
                        if (P.resultType == "BOTH"){
                                paths = P.asPaths(paths);
                                var newResult = [];
                                for (var i =0;i <paths.length;i++)
                                        newResult.push({path:paths[i],value:result[i]});
                                return newResult;
                        }
                        return P.resultType == "PATH" ? P.asPaths(paths):result;
                },
                walk: function(val, f){
                        if (val instanceof Array){
                                for (var i=0,n=val.length; i<n; i++)
                                        if (i in val)
                                                f(i);
                        }
                        else if (typeof val === "object"){
                                for (var m in val)
                                        if (val.hasOwnProperty(m))
                                                f(m);
                        }
                },
                eval: function(x, v){
                        try { return $ && v && eval(x.replace(/@/g,'v')); }
                        catch(e){ throw new SyntaxError("jsonPath: " + e.message + ": " + x.replace(/@/g, "v").replace(/\^/g, "_a")); }
                }
        };

        var $ = obj;
        if (expr && obj){
                return P.exec(P.normalize(expr).slice(1), obj, arg.evalType == "RESULT");
        }

        return false;

};