Improvements to json parsing (thanks Bradley Peabody)

It now remembers if a string was quoted with single or double quotes
and deals with both scenarios properly. Some cases of bad json could
go into an infinite loop, which now throw an exception.
Unwanted backslashes (something like \$ for example) now return the
literal character instead of throwing it away.

Author: bradleypeabody

src/com/rabbitmq/tools/json/JSONReader.java

@@ -88,8 +88,9 @@ private Object read() {
         skipWhiteSpace();
 
         if (c == '"' || c == '\'') {
+            char sep = c;
             next();
-            ret = string();
+            ret = string(sep);
         } else if (c == '[') {
             next();
             ret = array();
@@ -119,6 +120,10 @@ private Object read() {
         } else if (Character.isDigit(c) || c == '-') {
             ret = number();
         }
+        else {
+            // in this case we want to throw, not valid JSON
+            throw new IllegalStateException("Found invalid token while parsing JSON (around character "+(it.getIndex()-it.getBeginIndex())+"): " + ret);
+        }
 
         // System.out.println("token: " + ret); // enable this line to see the token stream
         token = ret;
@@ -179,9 +184,12 @@ private Object number() {
 	}
     }
 
-    private Object string() {
+    /**
+     * Read a string with a specific delimiter (either ' or ")
+     */
+    private Object string(char sep) {
         buf.setLength(0);
-        while (c != '"' && c != '\'') {
+        while (c != sep) {
             if (c == '\\') {
                 next();
                 if (c == 'u') {
@@ -191,6 +199,12 @@ private Object string() {
                     if (value != null) {
                         add(((Character) value).charValue());
                     }
+                    // if escaping is invalid, if we're going to ignore the error,
+                    // it makes more sense to put in the literal character instead
+                    // of just skipping it, so we do that
+                    else {
+                        add();
+                    }
                 }
             } else {
                 add();

test/src/com/rabbitmq/client/test/ClientTests.java

@@ -38,6 +38,7 @@ public static TestSuite suite() {
         suite.addTestSuite(com.rabbitmq.utility.IntAllocatorTests.class);
         suite.addTestSuite(AMQBuilderApiTest.class);
         suite.addTestSuite(AmqpUriTest.class);
+        suite.addTestSuite(JSONReadWriteTest.class);
         return suite;
     }
 }

test/src/com/rabbitmq/client/test/JSONReadWriteTest.java

@@ -0,0 +1,119 @@
+//  The contents of this file are subject to the Mozilla Public License
+//  Version 1.1 (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.mozilla.org/MPL/
+//
+//  Software distributed under the License is distributed on an "AS IS"
+//  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+//  the License for the specific language governing rights and
+//  limitations under the License.
+//
+//  The Original Code is RabbitMQ.
+//
+//  The Initial Developer of the Original Code is VMware, Inc.
+//  Copyright (c) 2007-2013 VMware, Inc.  All rights reserved.
+//
+
+
+package com.rabbitmq.client.test;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+
+import com.rabbitmq.tools.json.JSONWriter;
+import com.rabbitmq.tools.json.JSONReader;
+
+import junit.framework.TestCase;
+
+public class JSONReadWriteTest extends TestCase {
+
+    public void testReadWriteSimple() throws Exception {
+
+    	Object myRet;
+    	String myJson;
+
+    	// simple string
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write("blah"));
+    	assertEquals("blah", myRet);
+
+    	// simple int
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write(1));
+    	assertEquals(1, myRet);
+
+    	// string with double quotes
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write("t1-blah\"blah"));
+    	assertEquals("t1-blah\"blah", myRet);
+    	// string with single quotes
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write("t2-blah'blah"));
+    	assertEquals("t2-blah'blah", myRet);
+    	// string with two double quotes
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write("t3-blah\"n\"blah"));
+    	assertEquals("t3-blah\"n\"blah", myRet);
+    	// string with two single quotes
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write("t4-blah'n'blah"));
+    	assertEquals("t4-blah'n'blah", myRet);
+    	// string with a single and a double quote
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write("t4-blah'n\"blah"));
+    	assertEquals("t4-blah'n\"blah", myRet);
+
+    	// UTF-8 character
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write("smile \u9786"));
+    	// System.out.println("JSON: "+myJson);
+    	// System.out.println("JSON: "+myRet);
+    	assertEquals("smile \u9786", myRet);
+
+    	// null byte
+    	myRet = new JSONReader().read(myJson = new JSONWriter().write("smile \u0000"));
+    	// System.out.println("JSON: "+myJson);
+    	// System.out.println("JSON: "+myRet);
+    	assertEquals("smile \u0000", myRet);
+
+    }
+
+    public void testMoreComplicated() throws Exception {
+
+    	String v, s;
+    	Object t;
+
+    	s = "[\"foo\",{\"bar\":[\"baz\",null,1.0,2]}]";
+    	v = new JSONWriter().write(new JSONReader().read(s));
+    	assertEquals(s, v);
+
+    	s = "[\"foo\",{\"bar\":[\"b\\\"az\",null,1.0,2]}]";
+    	t = new JSONReader().read(s);
+    	v = new JSONWriter().write(t);
+    	assertEquals(s, v);
+
+    	s = "[\"foo\",{\"bar\":[\"b'az\",null,1.0,2]}]";
+    	v = new JSONWriter().write(new JSONReader().read(s));
+    	assertEquals(s, v);
+
+    	s = "[\"foo\",{\"bar\":[\"b'a'z\",null,1.0,2]}]";
+    	v = new JSONWriter().write(new JSONReader().read(s));
+    	assertEquals(s, v);
+
+    	s = "[\"foo\",{\"bar\":[\"b\\\"a\\\"z\",null,1.0,2]}]";
+    	v = new JSONWriter().write(new JSONReader().read(s));
+    	assertEquals(s, v);
+
+    }
+
+    public void testBadJSON() throws Exception {
+
+    	try {
+    		new JSONReader().read("[\"foo\",{\"bar\":[\"b\"az\",null,1.0,2]}]");
+    		fail("Should not have parsed");
+    	}
+    	catch (IllegalStateException e) {}
+
+    	try {
+	    	new JSONReader().read("[\"foo\",{\"bar\":[\"b\"a\"z\",null,1.0,2]}]");
+    		fail("Should not have parsed");
+    	}
+    	catch (IllegalStateException e) {}
+
+    }
+
+}