Use CBOR as binary format

Dropping cereal library which seems not well maintained.

CMakeLists.txt

@@ -421,18 +421,12 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${g2o_CXX_FLAGS}")
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${g2o_C_FLAGS}")
 
 find_package(Eigen3 3.3 REQUIRED)
-find_package(cereal)
 find_package(nlohmann_json 3.2.0)
 
 # Generate config.h
 set(G2O_OPENGL_FOUND ${OPENGL_FOUND})
 set(G2O_HAVE_CHOLMOD ${CHOLMOD_FOUND})
 set(G2O_HAVE_CSPARSE ${G2O_USE_CSPARSE})
-if (TARGET cereal::cereal)
-  set(G2O_HAVE_CEREAL 1)
-else()
-  set(G2O_HAVE_CEREAL 0)
-endif()
 if (TARGET nlohmann_json::nlohmann_json)
   set(G2O_HAVE_JSON 1)
 else()

config.h.in

@@ -7,7 +7,6 @@
 #cmakedefine G2O_SHARED_LIBS 1
 #cmakedefine G2O_LGPL_SHARED_LIBS 1
 
-#cmakedefine G2O_HAVE_CEREAL 1
 #cmakedefine G2O_HAVE_JSON 1
 
 // available sparse matrix libraries

g2o/core/io/io_binary.cpp

@@ -30,26 +30,35 @@
 
 #include "g2o/config.h"
 #include "g2o/core/abstract_graph.h"
-
-#ifdef G2O_HAVE_CEREAL
-#include <cereal/archives/portable_binary.hpp>
-#include <cereal/cereal.hpp>
-
-#include "io_wrapper_cereal.h"  // IWYU pragma: keep
-#else
 #include "g2o/stuff/logger.h"
-#endif  // HAVE CEREAL
+
+#ifdef G2O_HAVE_JSON
+#include "io_wrapper_json.h"
+#endif  // HAVE_JSON
 
 namespace g2o {
 
-#ifdef G2O_HAVE_CEREAL
+#ifdef G2O_HAVE_JSON
 
 std::optional<AbstractGraph> IoBinary::load(std::istream& input) {
-  return io::load<cereal::PortableBinaryInputArchive>(input, "BINARY");
+  try {
+    return json::fromJson(nlohmann::json::from_cbor(input));
+  } catch (const std::exception& e) {
+    G2O_ERROR("Exception while loading: {}", e.what());
+  }
+  return std::nullopt;
 }
 
 bool IoBinary::save(std::ostream& output, const AbstractGraph& graph) {
-  return io::save<cereal::PortableBinaryOutputArchive>(output, graph, "BINARY");
+  try {
+    std::vector<std::uint8_t> binary =
+        nlohmann::json::to_cbor(json::toJson(graph));
+    output.write(reinterpret_cast<char*>(binary.data()), binary.size());
+    return output.good();
+  } catch (const std::exception& e) {
+    G2O_ERROR("Exception while saving: {}", e.what());
+  }
+  return false;
 }
 
 #else

g2o/core/io/io_json.cpp

@@ -35,50 +35,28 @@
 
 #ifdef G2O_HAVE_JSON
 #include <nlohmann/json.hpp>
-#endif  // HAVE CEREAL
+
+#include "io_wrapper_json.h"
+#endif  // HAVE_JSON
 
 namespace g2o {
 
 #ifdef G2O_HAVE_JSON
 
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(AbstractGraph::AbstractParameter, tag, id,
-                                   value);
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(AbstractGraph::AbstractData, tag, data);
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(AbstractGraph::AbstractVertex, tag, id,
-                                   estimate, data);
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(AbstractGraph::AbstractEdge, tag, ids,
-                                   param_ids, measurement, information, data);
-
 std::optional<AbstractGraph> IoJson::load(std::istream& input) {
-  nlohmann::json json;
   try {
+    nlohmann::json json;
     input >> json;
-    const nlohmann::json& json_graph = json["graph"];
-    AbstractGraph graph;
-    graph.fixed() = json_graph["fixed"].get<std::vector<int>>();
-    graph.parameters() =
-        json_graph["params"]
-            .get<std::vector<AbstractGraph::AbstractParameter>>();
-    graph.vertices() = json_graph["vertices"]
-                           .get<std::vector<AbstractGraph::AbstractVertex>>();
-    graph.edges() =
-        json_graph["edges"].get<std::vector<AbstractGraph::AbstractEdge>>();
-    return graph;
+    return json::fromJson(json);
   } catch (const std::exception& e) {
     G2O_ERROR("Exception while saving: {}", e.what());
   }
   return std::nullopt;
 }
 
 bool IoJson::save(std::ostream& output, const AbstractGraph& graph) {
-  nlohmann::json json;
   try {
-    nlohmann::json& json_graph = json["graph"];
-    json_graph["fixed"] = graph.fixed();
-    json_graph["params"] = graph.parameters();
-    json_graph["vertices"] = graph.vertices();
-    json_graph["edges"] = graph.edges();
-    output << json;
+    output << json::toJson(graph);
   } catch (const std::exception& e) {
     G2O_ERROR("Exception while saving: {}", e.what());
     return false;

g2o/core/io/io_wrapper_json.h

@@ -0,0 +1,90 @@
+// g2o - General Graph Optimization
+// Copyright (C) 2011 R. Kuemmerle, G. Grisetti, W. Burgard
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+//   this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in the
+//   documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef G2O_CORE_IO_WRAPPER_JSON_H
+#define G2O_CORE_IO_WRAPPER_JSON_H
+
+#include "g2o/config.h"
+
+#ifdef G2O_HAVE_JSON
+#include <nlohmann/json.hpp>
+
+#include "g2o/core/abstract_graph.h"
+
+namespace g2o {
+
+NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(AbstractGraph::AbstractParameter, tag, id,
+                                   value);
+NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(AbstractGraph::AbstractData, tag, data);
+NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(AbstractGraph::AbstractVertex, tag, id,
+                                   estimate, data);
+NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(AbstractGraph::AbstractEdge, tag, ids,
+                                   param_ids, measurement, information, data);
+
+namespace json {
+
+/**
+ * @brief Versions of the IO API for the graph using cereal.
+ */
+enum class IoVersions {
+  kGraph = 0,
+  kData = 0,
+  kParameter = 0,
+  kGraphElement = 0,
+  kVertex = 0,
+  kEdge = 0,
+};
+
+inline AbstractGraph fromJson(const nlohmann::json& json) {
+  const nlohmann::json& json_graph = json["graph"];
+  AbstractGraph graph;
+  graph.fixed() = json_graph["fixed"].get<std::vector<int>>();
+  graph.parameters() =
+      json_graph["params"].get<std::vector<AbstractGraph::AbstractParameter>>();
+  graph.vertices() =
+      json_graph["vertices"].get<std::vector<AbstractGraph::AbstractVertex>>();
+  graph.edges() =
+      json_graph["edges"].get<std::vector<AbstractGraph::AbstractEdge>>();
+  return graph;
+}
+
+inline nlohmann::json toJson(const AbstractGraph& graph) {
+  nlohmann::json json;
+  nlohmann::json& json_graph = json["graph"];
+  json_graph["fixed"] = graph.fixed();
+  json_graph["params"] = graph.parameters();
+  json_graph["vertices"] = graph.vertices();
+  json_graph["edges"] = graph.edges();
+  return json;
+}
+
+}  // namespace json
+
+}  // namespace g2o
+
+#endif  // HAVE_JSON
+
+#endif

todo.md

@@ -1,5 +1,6 @@
-[ ] drop cereal (replace with json directly, drop xml)
+[x] drop cereal (replace with json directly, drop xml)
 [ ] install json on Windows CI
+[ ] wrap io_format.h to python
 [x] wrap simulator into library
 [x] add config types for simulation
 [ ] add tests for simulator