Adding JsonBufferTest & expanding escape sequences

Author: dougqh

dd-java-agent/src/main/java/datadog/trace/bootstrap/JsonBuffer.java

@@ -182,29 +182,49 @@ private JsonBuffer writeStringLiteral(String str) {
     try {
       writer.write('"');
 
-      // DQH - indexOf is usually intrinsified to use SIMD &
-      // no escaping will be the common case
-      if (str.indexOf('"') == -1 && str.indexOf('\\') != -1) {
-        writer.write(str);
-      } else {
-        for (int i = 0; i < str.length(); ++i) {
-          char ch = str.charAt(i);
-
-          switch (ch) {
-            case '"':
-              writer.write("\\\"");
-              break;
-
-            case '\\':
-              writer.write("\\\\");
-              break;
-
-            default:
-              writer.write(ch);
-              break;
-          }
+	  for (int i = 0; i < str.length(); ++i) {
+        char ch = str.charAt(i);
+
+        // Based on https://keploy.io/blog/community/json-escape-and-unescape
+        switch (ch) {
+          case '"':
+            writer.write("\\\"");
+            break;
+
+          case '\\':
+            writer.write("\\\\");
+            break;
+            
+          case '/':
+        	writer.write("\\/");
+        	break;
+        	
+          case '\b':
+        	writer.write("\\b");
+        	break;
+        	
+          case '\f':
+        	writer.write("\\f");
+        	break;
+        
+          case '\n':
+            writer.write("\\n");
+            break;
+          
+          case '\r':
+        	writer.write("\\r");
+        	break;
+        	
+          case '\t':
+        	writer.write("\\t");
+        	break;
+
+          default:
+            writer.write(ch);
+            break;
         }
-      }
+	  }
+	  
       writer.write('"');
     } catch (IOException e) {
       // ignore

dd-java-agent/src/test/groovy/datadog/trace/bootstrap/JsonBufferTest.groovy

@@ -0,0 +1,52 @@
+package datadog.trace.agent
+
+import datadog.trace.bootstrap.JsonBuffer
+import spock.lang.Specification
+
+class JsonBufferTest extends Specification {
+  def "object"() {
+    when:
+    def jsonBuffer = new JsonBuffer()
+    jsonBuffer.beginObject()
+    jsonBuffer.name("foo").value("bar")
+    jsonBuffer.name("pi").value(3_142);
+    jsonBuffer.name("true").value(true);
+    jsonBuffer.name("false").value(false);
+    jsonBuffer.endObject();
+
+    then:
+    jsonBuffer.toString() == '{"foo":"bar","pi":3142,"true":true,"false":false}'
+  }
+  
+  def "array"() {
+    when:
+    def jsonBuffer = new JsonBuffer()
+    jsonBuffer.beginArray()
+    jsonBuffer.value("foo");
+    jsonBuffer.value("baz");
+    jsonBuffer.value("bar");
+    jsonBuffer.value("quux");
+    jsonBuffer.endArray();
+
+    then:
+    jsonBuffer.toString() == '["foo","baz","bar","quux"]'
+  }
+  
+  def "escaping"() {
+    when:
+    def jsonBuffer = new JsonBuffer()
+    jsonBuffer.beginArray();
+    jsonBuffer.value('"');
+    jsonBuffer.value("\\");
+    jsonBuffer.value("/");
+    jsonBuffer.value("\b");
+    jsonBuffer.value("\f");
+    jsonBuffer.value("\n");
+    jsonBuffer.value("\r");
+    jsonBuffer.value("\t");
+    jsonBuffer.endArray();
+    
+    then:
+    jsonBuffer.toString() == '["\\"","\\\\","\\/","\\b","\\f","\\n","\\r","\\t"]'
+  }
+}