Add support for JsonCpp

CMakeLists.txt

@@ -40,6 +40,7 @@ option_if_not_defined(CPPDAP_TSAN "Build dap with thread sanitizer" OFF)
 option_if_not_defined(CPPDAP_INSTALL_VSCODE_EXAMPLES "Build and install dap examples into vscode extensions directory" OFF)
 option_if_not_defined(CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE "Use nlohmann_json with find_package() instead of building internal submodule" OFF)
 option_if_not_defined(CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE "Use RapidJSON with find_package()" OFF)
+option_if_not_defined(CPPDAP_USE_EXTERNAL_JSONCPP_PACKAGE "Use JsonCpp with find_package()" OFF)
 
 ###########################################################
 # Directories
@@ -71,14 +72,20 @@ endif(CPPDAP_BUILD_TESTS)
 # JSON library
 ###########################################################
 
-if(CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE AND CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE)
-    message(FATAL_ERROR "Don't set both CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE and CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE")
+if((CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE AND CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE) OR
+    (CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE AND CPPDAP_USE_EXTERNAL_JSONCPP_PACKAGE) OR
+    (CPPDAP_USE_EXTERNAL_JSONCPP_PACKAGE AND CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE))
+    message(FATAL_ERROR "At most one of CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE, \
+CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE, and CPPDAP_USE_EXTERNAL_JSONCPP_PACKAGE can be set.")
 elseif(CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE)
     find_package(nlohmann_json CONFIG REQUIRED)
     set(CPPDAP_JSON_LIBRARY "nlohmann")
 elseif(CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE)
     find_package(RapidJSON CONFIG REQUIRED)
     set(CPPDAP_JSON_LIBRARY "rapid")
+elseif(CPPDAP_USE_EXTERNAL_JSONCPP_PACKAGE)
+    find_package(jsoncpp CONFIG REQUIRED)
+    set(CPPDAP_JSON_LIBRARY "jsoncpp")
 endif()
 
 if(NOT DEFINED CPPDAP_JSON_LIBRARY)
@@ -91,6 +98,8 @@ if(NOT DEFINED CPPDAP_JSON_LIBRARY)
         set(CPPDAP_JSON_LIBRARY "nlohmann")
     elseif(EXISTS "${CPPDAP_JSON_DIR}/include/rapidjson")
         set(CPPDAP_JSON_LIBRARY "rapid")
+    elseif(EXISTS "${CPPDAP_JSON_DIR}/include/json")
+        set(CPPDAP_JSON_LIBRARY "jsoncpp")
     else()
         message(FATAL_ERROR "Could not determine JSON library from ${CPPDAP_JSON_DIR}")
     endif()
@@ -139,6 +148,8 @@ function(cppdap_set_json_links target)
         target_link_libraries(${target} PRIVATE "$<BUILD_INTERFACE:nlohmann_json::nlohmann_json>")
     elseif(CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE)
         target_link_libraries(${target} PRIVATE rapidjson)
+    elseif(CPPDAP_USE_EXTERNAL_JSONCPP_PACKAGE)
+        target_link_libraries(${target} PRIVATE JsonCpp::JsonCpp)
     else()
         target_include_directories(${target} PRIVATE "${CPPDAP_JSON_DIR}/include/")
     endif()    

README.md

@@ -19,6 +19,8 @@ cd <path-to-cppdap>
 git submodule update --init
 ```
 
+Alternatively, `cppdap` can use the [`RapidJSON` library](https://rapidjson.org/) or the [`JsonCpp` library](https://github.com/open-source-parsers/jsoncpp) for JSON serialization. Use the `CPPDAP_USE_EXTERNAL_NLOHMANN_JSON_PACKAGE`, `CPPDAP_USE_EXTERNAL_RAPIDJSON_PACKAGE`, and `CPPDAP_USE_EXTERNAL_JSONCPP_PACKAGE` CMake cache variables to select which library to use.
+
 ## Building
 
 ### Linux and macOS

src/json_serializer.h

@@ -19,6 +19,8 @@
 #include "nlohmann_json_serializer.h"
 #elif defined(CPPDAP_JSON_RAPID)
 #include "rapid_json_serializer.h"
+#elif defined(CPPDAP_JSON_JSONCPP)
+#include "jsoncpp_json_serializer.h"
 #else
 #error "Unrecognised cppdap JSON library"
 #endif
@@ -32,6 +34,9 @@ using Serializer = NlohmannSerializer;
 #elif defined(CPPDAP_JSON_RAPID)
 using Deserializer = RapidDeserializer;
 using Serializer = RapidSerializer;
+#elif defined(CPPDAP_JSON_JSONCPP)
+using Deserializer = JsonCppDeserializer;
+using Serializer = JsonCppSerializer;
 #else
 #error "Unrecognised cppdap JSON library"
 #endif

src/jsoncpp_json_serializer.cpp

@@ -0,0 +1,271 @@
+// Copyright 2023 Microsoft
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "jsoncpp_json_serializer.h"
+
+#include "null_json_serializer.h"
+
+#include <json/json.h>
+#include <cstdlib>
+
+namespace dap {
+namespace json {
+
+JsonCppDeserializer::JsonCppDeserializer(const std::string& str)
+    : json(new Json::Value(JsonCppDeserializer::parse(str))), ownsJson(true) {}
+
+JsonCppDeserializer::JsonCppDeserializer(const Json::Value* json)
+    : json(json), ownsJson(false) {}
+
+JsonCppDeserializer::~JsonCppDeserializer() {
+  if (ownsJson) {
+    delete json;
+  }
+}
+
+bool JsonCppDeserializer::deserialize(dap::boolean* v) const {
+  if (!json->isBool()) {
+    return false;
+  }
+  *v = json->asBool();
+  return true;
+}
+
+bool JsonCppDeserializer::deserialize(dap::integer* v) const {
+  if (!json->isInt64()) {
+    return false;
+  }
+  *v = json->asInt64();
+  return true;
+}
+
+bool JsonCppDeserializer::deserialize(dap::number* v) const {
+  if (!json->isNumeric()) {
+    return false;
+  }
+  *v = json->asDouble();
+  return true;
+}
+
+bool JsonCppDeserializer::deserialize(dap::string* v) const {
+  if (!json->isString()) {
+    return false;
+  }
+  *v = json->asString();
+  return true;
+}
+
+bool JsonCppDeserializer::deserialize(dap::object* v) const {
+  v->reserve(json->size());
+  for (auto i = json->begin(); i != json->end(); i++) {
+    JsonCppDeserializer d(&*i);
+    dap::any val;
+    if (!d.deserialize(&val)) {
+      return false;
+    }
+    (*v)[i.name()] = val;
+  }
+  return true;
+}
+
+bool JsonCppDeserializer::deserialize(dap::any* v) const {
+  if (json->isBool()) {
+    *v = dap::boolean(json->asBool());
+  } else if (json->type() == Json::ValueType::realValue) {
+    // json->isDouble() returns true for integers as well, so we need to
+    // explicitly look for the realValue type.
+    *v = dap::number(json->asDouble());
+  } else if (json->isInt64()) {
+    *v = dap::integer(json->asInt64());
+  } else if (json->isString()) {
+    *v = json->asString();
+  } else if (json->isObject()) {
+    dap::object obj;
+    if (!deserialize(&obj)) {
+      return false;
+    }
+    *v = obj;
+  } else if (json->isArray()) {
+    dap::array<any> arr;
+    if (!deserialize(&arr)) {
+      return false;
+    }
+    *v = arr;
+  } else if (json->isNull()) {
+    *v = null();
+  } else {
+    return false;
+  }
+  return true;
+}
+
+size_t JsonCppDeserializer::count() const {
+  return json->size();
+}
+
+bool JsonCppDeserializer::array(
+    const std::function<bool(dap::Deserializer*)>& cb) const {
+  if (!json->isArray()) {
+    return false;
+  }
+  for (const auto& value : *json) {
+    JsonCppDeserializer d(&value);
+    if (!cb(&d)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool JsonCppDeserializer::field(
+    const std::string& name,
+    const std::function<bool(dap::Deserializer*)>& cb) const {
+  if (!json->isObject()) {
+    return false;
+  }
+  auto value = json->find(name.data(), name.data() + name.size());
+  if (value == nullptr) {
+    return cb(&NullDeserializer::instance);
+  }
+  JsonCppDeserializer d(value);
+  return cb(&d);
+}
+
+Json::Value JsonCppDeserializer::parse(const std::string& text) {
+  Json::CharReaderBuilder builder;
+  auto jsonReader = std::unique_ptr<Json::CharReader>(builder.newCharReader());
+  Json::Value json;
+  std::string error;
+  if (!jsonReader->parse(text.data(), text.data() + text.size(), &json,
+                         &error)) {
+    // cppdap expects that the JSON layer does not throw exceptions.
+    std::abort();
+  }
+  return json;
+}
+
+JsonCppSerializer::JsonCppSerializer()
+    : json(new Json::Value()), ownsJson(true) {}
+
+JsonCppSerializer::JsonCppSerializer(Json::Value* json)
+    : json(json), ownsJson(false) {}
+
+JsonCppSerializer::~JsonCppSerializer() {
+  if (ownsJson) {
+    delete json;
+  }
+}
+
+std::string JsonCppSerializer::dump() const {
+  Json::StreamWriterBuilder writer;
+  return Json::writeString(writer, *json);
+}
+
+bool JsonCppSerializer::serialize(dap::boolean v) {
+  *json = (bool)v;
+  return true;
+}
+
+bool JsonCppSerializer::serialize(dap::integer v) {
+  *json = (int64_t)v;
+  return true;
+}
+
+bool JsonCppSerializer::serialize(dap::number v) {
+  *json = (double)v;
+  return true;
+}
+
+bool JsonCppSerializer::serialize(const dap::string& v) {
+  *json = v;
+  return true;
+}
+
+bool JsonCppSerializer::serialize(const dap::object& v) {
+  if (!json->isObject()) {
+    *json = Json::Value(Json::objectValue);
+  }
+  for (auto& it : v) {
+    JsonCppSerializer s(&(*json)[it.first]);
+    if (!s.serialize(it.second)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool JsonCppSerializer::serialize(const dap::any& v) {
+  if (v.is<dap::boolean>()) {
+    *json = (bool)v.get<dap::boolean>();
+  } else if (v.is<dap::integer>()) {
+    *json = (int64_t)v.get<dap::integer>();
+  } else if (v.is<dap::number>()) {
+    *json = (double)v.get<dap::number>();
+  } else if (v.is<dap::string>()) {
+    *json = v.get<dap::string>();
+  } else if (v.is<dap::object>()) {
+    // reachable if dap::object nested is inside other dap::object
+    return serialize(v.get<dap::object>());
+  } else if (v.is<dap::null>()) {
+  } else {
+    // reachable if array or custom serialized type is nested inside other
+    auto type = get_any_type(v);
+    auto value = get_any_val(v);
+    if (type && value) {
+      return type->serialize(this, value);
+    }
+    return false;
+  }
+  return true;
+}
+
+bool JsonCppSerializer::array(size_t count,
+                              const std::function<bool(dap::Serializer*)>& cb) {
+  *json = Json::Value(Json::arrayValue);
+  for (size_t i = 0; i < count; i++) {
+    JsonCppSerializer s(&(*json)[Json::Value::ArrayIndex(i)]);
+    if (!cb(&s)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool JsonCppSerializer::object(
+    const std::function<bool(dap::FieldSerializer*)>& cb) {
+  struct FS : public FieldSerializer {
+    Json::Value* const json;
+
+    FS(Json::Value* json) : json(json) {}
+    bool field(const std::string& name, const SerializeFunc& cb) override {
+      JsonCppSerializer s(&(*json)[name]);
+      auto res = cb(&s);
+      if (s.removed) {
+        json->removeMember(name);
+      }
+      return res;
+    }
+  };
+
+  *json = Json::Value(Json::objectValue);
+  FS fs{json};
+  return cb(&fs);
+}
+
+void JsonCppSerializer::remove() {
+  removed = true;
+}
+
+}  // namespace json
+}  // namespace dap

src/jsoncpp_json_serializer.h

@@ -0,0 +1,134 @@
+// Copyright 2023 Microsoft
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef dap_jsoncpp_json_serializer_h
+#define dap_jsoncpp_json_serializer_h
+
+#include "dap/protocol.h"
+#include "dap/serialization.h"
+#include "dap/types.h"
+
+#include <json/forwards.h>
+
+namespace dap {
+namespace json {
+
+struct JsonCppDeserializer : public dap::Deserializer {
+  explicit JsonCppDeserializer(const std::string&);
+  ~JsonCppDeserializer();
+
+  // dap::Deserializer compliance
+  bool deserialize(boolean* v) const override;
+  bool deserialize(integer* v) const override;
+  bool deserialize(number* v) const override;
+  bool deserialize(string* v) const override;
+  bool deserialize(object* v) const override;
+  bool deserialize(any* v) const override;
+  size_t count() const override;
+  bool array(const std::function<bool(dap::Deserializer*)>&) const override;
+  bool field(const std::string& name,
+             const std::function<bool(dap::Deserializer*)>&) const override;
+
+  // Unhide base overloads
+  template <typename T>
+  inline bool field(const std::string& name, T* v) {
+    return dap::Deserializer::field(name, v);
+  }
+
+  template <typename T,
+            typename = std::enable_if<TypeOf<T>::has_custom_serialization>>
+  inline bool deserialize(T* v) const {
+    return dap::Deserializer::deserialize(v);
+  }
+
+  template <typename T>
+  inline bool deserialize(dap::array<T>* v) const {
+    return dap::Deserializer::deserialize(v);
+  }
+
+  template <typename T>
+  inline bool deserialize(dap::optional<T>* v) const {
+    return dap::Deserializer::deserialize(v);
+  }
+
+  template <typename T0, typename... Types>
+  inline bool deserialize(dap::variant<T0, Types...>* v) const {
+    return dap::Deserializer::deserialize(v);
+  }
+
+  template <typename T>
+  inline bool field(const std::string& name, T* v) const {
+    return dap::Deserializer::deserialize(name, v);
+  }
+
+ private:
+  JsonCppDeserializer(const Json::Value*);
+  static Json::Value parse(const std::string& text);
+  const Json::Value* const json;
+  const bool ownsJson;
+};
+
+struct JsonCppSerializer : public dap::Serializer {
+  JsonCppSerializer();
+  ~JsonCppSerializer();
+
+  std::string dump() const;
+
+  // dap::Serializer compliance
+  bool serialize(boolean v) override;
+  bool serialize(integer v) override;
+  bool serialize(number v) override;
+  bool serialize(const string& v) override;
+  bool serialize(const dap::object& v) override;
+  bool serialize(const any& v) override;
+  bool array(size_t count,
+             const std::function<bool(dap::Serializer*)>&) override;
+  bool object(const std::function<bool(dap::FieldSerializer*)>&) override;
+  void remove() override;
+
+  // Unhide base overloads
+  template <typename T,
+            typename = std::enable_if<TypeOf<T>::has_custom_serialization>>
+  inline bool serialize(const T& v) {
+    return dap::Serializer::serialize(v);
+  }
+
+  template <typename T>
+  inline bool serialize(const dap::array<T>& v) {
+    return dap::Serializer::serialize(v);
+  }
+
+  template <typename T>
+  inline bool serialize(const dap::optional<T>& v) {
+    return dap::Serializer::serialize(v);
+  }
+
+  template <typename T0, typename... Types>
+  inline bool serialize(const dap::variant<T0, Types...>& v) {
+    return dap::Serializer::serialize(v);
+  }
+
+  inline bool serialize(const char* v) { return dap::Serializer::serialize(v); }
+
+ private:
+  JsonCppSerializer(Json::Value*);
+  Json::Value* const json;
+  const bool ownsJson;
+  bool removed = false;
+};
+
+}  // namespace json
+}  // namespace dap
+
+#endif  // dap_jsoncpp_json_serializer_h