Use FastWriter for TlvJson (#18456)

TlvJson now outputs a more RPC-friendly string, instead of a
human-readable string.

src/lib/support/jsontlv/TlvJson.cpp

@@ -106,7 +106,8 @@ void InsertKeyValue(Json::Value & json, const KeyContext & keyContext, T val)
 
 std::string JsonToString(Json::Value & json)
 {
- Json::StyledWriter writer;
+ Json::FastWriter writer;
+ writer.omitEndingLineFeed();
  return writer.write(json);
 }
 

src/lib/support/tests/TestTlvToJson.cpp

@@ -54,55 +54,30 @@ CHIP_ERROR SetupReader()
 
 bool Matches(const char * referenceString, Json::Value & generatedValue)
 {
- Json::StyledWriter writer;
  auto generatedStr = JsonToString(generatedValue);
 
- auto matches = (generatedStr == std::string(referenceString));
+ // Normalize the reference string to the expected compact value.
+ Json::Reader reader;
+ Json::Value referenceValue;
+ reader.parse(referenceString, referenceValue);
+
+ Json::FastWriter writer;
+ writer.omitEndingLineFeed();
+ auto compactReferenceString = writer.write(referenceValue);
+
+ auto matches = (generatedStr == compactReferenceString);
 
  if (!matches)
  {
  printf("Didn't match!\n");
  printf("Reference:\n");
- printf("%s\n", referenceString);
+ printf("%s\n", compactReferenceString.c_str());
 
  printf("Generated:\n");
  printf("%s\n", generatedStr.c_str());
  }
 
  return matches;
-
-#if 0
- //
- // Converting the reference string to a JSON representation and comparing
- // that against the generated JSON object would have been preferable. This avoids
- // the need to have reference strings expressed precisely to match the generated string
- // from the JSON converter, right down to the number of spaces,etc. This would have made
- // the reference string less britle and coupled to the jsoncpp converter implementation.
- //
- // However, jsoncpp converter converts positive values in the JSON to a signed
- // integer C type. This results in a mis-match with the generated JSON objects
- // that are created from spec-compliant TLV that correctly represents them as unsigned
- // integers in the JSON object.
- //
- // This mismatch nullifies this approach unfortunately.
- //
- // TODO: Investigate a way to compare using JSON objects.
- //
- Json::Reader reader;
- Json::Value referenceValue;
-
- bool ret = reader.parse(referenceString, referenceValue);
- if (ret != true) {
- return ret;
- }
-
- std::cout << generatedValue << "\n";
- std::cout << referenceValue << "\n";
-
- int rett = generatedValue.compare(referenceValue);
- printf("%d\n", rett);
- return (rett == 0);
-#endif
 }
 
 template <typename T>