Use the jsoncons non-throwing versions of decode for cbor and ubjson (#550)

Co-authored-by: Bryce Schober <bryce.schober@dynon.com>

Author: Ian-Flury

include/rfl/cbor/read.hpp

@@ -21,30 +21,24 @@ using InputVarType = typename Reader::InputVarType;
 template <class T, class... Ps>
 Result<internal::wrap_in_rfl_array_t<T>> read(
     const concepts::ContiguousByteContainer auto& _bytes) {
-  try {
-    auto val = jsoncons::cbor::decode_cbor<jsoncons::json>(_bytes);
+  auto result = jsoncons::cbor::try_decode_cbor<jsoncons::json>(_bytes);
+  if (result.has_value()) {
     auto r = Reader();
-    return Parser<T, Processors<Ps...>>::read(r, InputVarType{&val});
-  } catch (const jsoncons::ser_error& e) {
-    std::string error("Could not parse CBOR: ");
-    error.append(e.what());
-    return rfl::error(error);
+    return Parser<T, Processors<Ps...>>::read(r, InputVarType{&result.value()});
+  } else {
+    return rfl::error("Could not parse CBOR: " + result.error().message());
   }
 }
 
 /// Parses an object from a stream.
 template <class T, class... Ps>
 Result<internal::wrap_in_rfl_array_t<T>> read(std::istream& _stream) {
-  // TODO: Use a non-throwing decode_cbor(), pending
-  // https://github.com/danielaparker/jsoncons/issues/615
-  try {
-    auto val = jsoncons::cbor::decode_cbor<jsoncons::json>(_stream);
+  auto result = jsoncons::cbor::try_decode_cbor<jsoncons::json>(_stream);
+  if (result.has_value()) {
     auto r = Reader();
-    return Parser<T, Processors<Ps...>>::read(r, InputVarType{&val});
-  } catch (const jsoncons::ser_error& e) {
-    std::string error("Could not parse CBOR: ");
-    error.append(e.what());
-    return rfl::error(error);
+    return Parser<T, Processors<Ps...>>::read(r, InputVarType{&result.value()});
+  } else {
+    return rfl::error("Could not parse CBOR: " + result.error().message());
   }
 }
 

include/rfl/ubjson/read.hpp

@@ -22,32 +22,24 @@ using InputVarType = typename Reader::InputVarType;
 template <class T, class... Ps>
 Result<internal::wrap_in_rfl_array_t<T>> read(
     const concepts::ContiguousByteContainer auto& _bytes) {
-  // TODO: Use a non-throwing decode_ubjson(), pending
-  // https://github.com/danielaparker/jsoncons/issues/615
-  try {
-    auto val = jsoncons::ubjson::decode_ubjson<jsoncons::json>(_bytes);
+  auto result = jsoncons::ubjson::try_decode_ubjson<jsoncons::json>(_bytes);
+  if (result.has_value()) {
     auto r = Reader();
-    return Parser<T, Processors<Ps...>>::read(r, InputVarType{&val});
-  } catch (const jsoncons::ser_error& e) {
-    std::string error("Could not parse UBJSON: ");
-    error.append(e.what());
-    return rfl::error(error);
+    return Parser<T, Processors<Ps...>>::read(r, InputVarType{&result.value()});
+  } else {
+    return rfl::error("Could not parse UBJSON: " + result.error().message());
   }
 }
 
 /// Parses an object from a stream.
 template <class T, class... Ps>
 Result<internal::wrap_in_rfl_array_t<T>> read(std::istream& _stream) {
-  // TODO: Use a non-throwing decode_ubjson(), pending
-  // https://github.com/danielaparker/jsoncons/issues/615
-  try {
-    auto val = jsoncons::ubjson::decode_ubjson<jsoncons::json>(_stream);
+  auto result = jsoncons::ubjson::try_decode_ubjson<jsoncons::json>(_stream);
+  if (result.has_value()) {
     auto r = Reader();
-    return Parser<T, Processors<Ps...>>::read(r, InputVarType{&val});
-  } catch (const jsoncons::ser_error& e) {
-    std::string error("Could not parse UBJSON: ");
-    error.append(e.what());
-    return rfl::error(error);
+    return Parser<T, Processors<Ps...>>::read(r, InputVarType{&result.value()});
+  } else {
+    return rfl::error("Could not parse UBJSON: " + result.error().message());
   }
 }
 

tests/README.md

@@ -45,7 +45,7 @@ ctest --test-dir build --output-on-failure
 
 Or you can run tests individually, as in:
 
-```
+```shell
 ./build/tests/avro/reflect-cpp-avro-tests
 ./build/tests/bson/reflect-cpp-bson-tests
 ./build/tests/capnproto/reflect-cpp-capnproto-tests

tests/cbor/test_error_messages.cpp

@@ -15,45 +15,66 @@ struct Person {
   std::vector<Person> children;
 };
 
-TEST(cbor, test_field_error_messages) {
+TEST(cbor, test_empty_field_error_messages) {
+  // Use JSON input to generic parser for convenient flexible test input
+  const std::string faulty_string =
+      R"({})";
+  const auto faulty_generic = rfl::json::read<rfl::Generic>(faulty_string);
+  const auto faulty_cbor = rfl::cbor::write(faulty_generic);
+
+  rfl::Result<Person> result = rfl::error("result didn't get set");
+  EXPECT_NO_THROW({
+    result = rfl::cbor::read<Person>(faulty_cbor);
+  });
+
+    const std::string expected = R"(Found 4 errors:
+1) Field named 'firstName' not found.
+2) Field named 'lastName' not found.
+3) Field named 'birthday' not found.
+4) Field named 'children' not found.)";
+  EXPECT_EQ(result.error().what(), expected);
+
+  EXPECT_FALSE(result.has_value());
+}
+
+TEST(cbor, test_field_type_error_messages) {
+  // Use JSON input to generic parser for convenient flexible test input
   const std::string faulty_string =
       R"({"firstName":"Homer","lastName":12345,"birthday":"04/19/1987"})";
   const auto faulty_generic = rfl::json::read<rfl::Generic>(faulty_string);
   const auto faulty_cbor = rfl::cbor::write(faulty_generic);
-  const auto result = rfl::cbor::read<Person>(faulty_cbor);
+
+  rfl::Result<Person> result = rfl::error("result didn't get set");
+  EXPECT_NO_THROW({
+    result = rfl::cbor::read<Person>(faulty_cbor);
+  });
 
   // Order of errors is different than input JSON because rfl::Generic doesn't preserve order
   const std::string expected = R"(Found 3 errors:
 1) Failed to parse field 'birthday': String '04/19/1987' did not match format '%Y-%m-%d'.
 2) Failed to parse field 'lastName': Could not cast to string.
 3) Field named 'children' not found.)";
 
-  EXPECT_TRUE(!result.has_value() && true);
+  EXPECT_FALSE(result.has_value());
 
   EXPECT_EQ(result.error().what(), expected);
 }
 
 TEST(cbor, test_decode_error_without_exception) {
-  const std::string good_string =
-      R"({"firstName":"Homer","lastName":"Simpson","birthday":"1987-04-19"})";
-  const auto good_generic = rfl::json::read<rfl::Generic>(good_string);
-  auto faulty_cbor = rfl::cbor::write(good_generic);
-  faulty_cbor[1] = '\xff';  // Corrupt structure of CBOR encoding
+  const Person homer{"Homer", "Simpson", "1987-04-19"};
+  auto faulty_cbor = rfl::cbor::write(homer);
+  faulty_cbor[1] = '\xfe';  // Corrupt structure of CBOR encoding
 
   rfl::Result<Person> result = rfl::error("result didn't get set");
   EXPECT_NO_THROW({
     result = rfl::cbor::read<Person>(faulty_cbor);
   });
 
   // A proposal: A generic prefix, followed by the underlying library's error output
-    const std::string expected = R"(Found 4 errors:
-1) Field named 'firstName' not found.
-2) Field named 'lastName' not found.
-3) Field named 'birthday' not found.
-4) Field named 'children' not found.)";
+  const std::string expected = R"(Could not parse CBOR: An unknown type was found in the stream at position 1)";
   EXPECT_EQ(result.error().what(), expected);
 
-  EXPECT_TRUE(!result.has_value() && true);
+  EXPECT_FALSE(result.has_value());
 }
 
 }  // namespace test_error_messages

tests/ubjson/test_error_messages.cpp

@@ -15,29 +15,54 @@ struct Person {
   std::vector<Person> children;
 };
 
-TEST(ubjson, test_field_error_messages) {
+TEST(ubjson, test_empty_field_error_messages) {
+  // Use JSON input to generic parser for convenient flexible test input
+  const std::string faulty_string =
+      R"({})";
+  const auto faulty_generic = rfl::json::read<rfl::Generic>(faulty_string);
+  const auto faulty_ubjson = rfl::ubjson::write(faulty_generic);
+
+  rfl::Result<Person> result = rfl::error("result didn't get set");
+  EXPECT_NO_THROW({
+    result = rfl::ubjson::read<Person>(faulty_ubjson);
+  });
+
+    const std::string expected = R"(Found 4 errors:
+1) Field named 'firstName' not found.
+2) Field named 'lastName' not found.
+3) Field named 'birthday' not found.
+4) Field named 'children' not found.)";
+  EXPECT_EQ(result.error().what(), expected);
+
+  EXPECT_FALSE(result.has_value());
+}
+
+TEST(ubjson, test_field_type_error_messages) {
+  // Use JSON input to generic parser for convenient flexible test input
   const std::string faulty_string =
       R"({"firstName":"Homer","lastName":12345,"birthday":"04/19/1987"})";
   const auto faulty_generic = rfl::json::read<rfl::Generic>(faulty_string);
   const auto faulty_ubjson = rfl::ubjson::write(faulty_generic);
-  const auto result = rfl::ubjson::read<Person>(faulty_ubjson);
+
+  rfl::Result<Person> result = rfl::error("result didn't get set");
+  EXPECT_NO_THROW({
+    result = rfl::ubjson::read<Person>(faulty_ubjson);
+  });
 
   // Order of errors is different than input JSON because rfl::Generic doesn't preserve order
   const std::string expected = R"(Found 3 errors:
 1) Failed to parse field 'birthday': String '04/19/1987' did not match format '%Y-%m-%d'.
 2) Failed to parse field 'lastName': Could not cast to string.
 3) Field named 'children' not found.)";
 
-  EXPECT_TRUE(!result.has_value() && true);
+  EXPECT_FALSE(result.has_value());
 
   EXPECT_EQ(result.error().what(), expected);
 }
 
 TEST(ubjson, test_decode_error_without_exception) {
-  const std::string good_string =
-      R"({"firstName":"Homer","lastName":"Simpson","birthday":"1987-04-19"})";
-  const auto good_generic = rfl::json::read<rfl::Generic>(good_string);
-  auto faulty_ubjson = rfl::ubjson::write(good_generic);
+  const Person homer{"Homer", "Simpson", "1987-04-19"};
+  auto faulty_ubjson = rfl::ubjson::write(homer);
   faulty_ubjson[0] = '\xff';  // Corrupt structure of ubjson encoding
 
   rfl::Result<Person> result = rfl::error("result didn't get set");
@@ -49,7 +74,7 @@ TEST(ubjson, test_decode_error_without_exception) {
   const std::string expected = R"(Could not parse UBJSON: Unknown type at position 1)";
   EXPECT_EQ(result.error().what(), expected);
 
-  EXPECT_TRUE(!result.has_value() && true);
+  EXPECT_FALSE(result.has_value());
 }
 
 }  // namespace test_error_messages