1 /*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * - Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * - Neither the name of Oracle nor the names of its
16 * contributors may be used to endorse or promote products derived
17 * from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
20 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*
33 * Hjson - "the Human JSON - A configuration file format that
34 * caters to humans and helps reduce the errors they make"
35 * See also: http://hjson.org/
36 *
37 * I wanted to see if we can use Nashorn Parser API (jdk9) to support
38 * similar flexible JSON extension with #nashorn. In this FlexiJSON.parse
39 * implementation, Nashorn Parser API is used to validate that the
40 * extendable flexi JSON is "data only" (i.e., no executable code) and
41 * then 'eval'ed to make an object out of it.
42 *
43 * FlexiJSON allows the following:
44 *
45 * * single and mutliple line comments anywhere
46 * * non-quoted property names and values
47 * * regexp literal values
48 * * omitting trailing comma
49 *
50 * When nashorn -scripting mode is enabled, FlexiJSON supports these
51 * as well:
52 *
53 * * shell style # comments
54 * * multiple line (Unix heredoc style) string values
55 */
56
57 "use strict";
58
59 function FlexiJSON() {}
60
61 // helper to locate Nashorn Parser API classes
62 FlexiJSON.treeType = function(name) {
63 return Java.type("jdk.nashorn.api.tree." + name);
64 }
65
66 // Nashorn Parser API classes used
67 FlexiJSON.ArrayLiteral = FlexiJSON.treeType("ArrayLiteralTree");
68 FlexiJSON.ExpressionStatement = FlexiJSON.treeType("ExpressionStatementTree");
69 FlexiJSON.ObjectLiteral = FlexiJSON.treeType("ObjectLiteralTree");
70 FlexiJSON.RegExpLiteral = FlexiJSON.treeType("RegExpLiteralTree");
71 FlexiJSON.Literal = FlexiJSON.treeType("LiteralTree");
72 FlexiJSON.Parser = FlexiJSON.treeType("Parser");
73 FlexiJSON.SimpleTreeVisitor = FlexiJSON.treeType("SimpleTreeVisitorES5_1");
74
75 // FlexiJSON.parse API
76
77 FlexiJSON.parse = function(str) {
78 var parser = (typeof $OPTIONS == "undefined")?
79 FlexiJSON.Parser.create() :
80 FlexiJSON.Parser.create("-scripting");
81
82 // force the string to be an expression by putting it inside (, )
83 str = "(" + str + ")";
84 var ast = parser.parse("<flexijsondoc>", str, null);
85 // Should not happen. parse would have thrown syntax error
86 if (!ast) {
87 return undefined;
88 }
89
90 // allowed 'literal' values in flexi JSON
91 function isLiteral(node) {
92 return node instanceof FlexiJSON.ArrayLiteral ||
93 node instanceof FlexiJSON.Literal ||
94 node instanceof FlexiJSON.ObjectLiteral ||
95 node instanceof FlexiJSON.RegExpLiteral;
96 }
97
98 var visitor;
99 ast.accept(visitor = new (Java.extend(FlexiJSON.SimpleTreeVisitor)) {
100 lineMap: null,
101
102 throwError: function(msg, node) {
103 if (this.lineMap) {
104 var pos = node.startPosition;
105 var line = this.lineMap.getLineNumber(pos);
106 var column = this.lineMap.getColumnNumber(pos);
107 // we introduced extra '(' at start. So, adjust column number
108 msg = msg + " @ " + line + ":" + (column - 1);
109 }
110 throw new TypeError(msg);
111 },
112
113 visitLiteral: function(node, extra) {
114 print(node.value);
115 },
116
117 visitExpressionStatement: function(node, extra) {
118 var expr = node.expression;
119 if (isLiteral(expr)) {
120 expr.accept(visitor, extra);
121 } else {
122 this.throwError("only literals can occur", expr);
123 }
124 },
125
126 visitArrayLiteral: function(node, extra) {
127 for each (var elem in node.elements) {
128 if (isLiteral(elem)) {
129 elem.accept(visitor, extra);
130 } else {
131 this.throwError("only literal array element value allowed", elem);
132 }
133 }
134 },
135
136 visitObjectLiteral: function(node, extra) {
137 for each (var prop in node.properties) {
138 if (prop.getter != null || prop.setter != null) {
139 this.throwError("getter/setter property not allowed", node);
140 }
141
142 var value = prop.value;
143 if (isLiteral(value)) {
144 value.accept(visitor, extra);
145 } else {
146 this.throwError("only literal property value allowed", value);
147 }
148 }
149 },
150
151 visitCompilationUnit: function(node, extra) {
152 this.lineMap = node.lineMap;
153 var elements = node.sourceElements;
154 if (elements.length > 1) {
155 this.throwError("more than one top level expression", node.sourceElements[1]);
156 }
157 var stat = node.sourceElements[0];
158 if (! (stat instanceof FlexiJSON.ExpressionStatement)) {
159 this.throwError("only one top level expresion allowed", stat);
160 }
161 stat.accept(visitor, extra);
162 },
163 }, null);
164
165 // safe to eval given string as flexi JSON!
166 return eval(str);
167 }