Refactor/Cleanup factory methods

include/gz/msgs/Factory.hh

@@ -17,45 +17,38 @@
 #ifndef GZ_MSGS_FACTORY_HH_
 #define GZ_MSGS_FACTORY_HH_
 
-#ifdef _MSC_VER
-#pragma warning(push)
-#pragma warning(disable: 4100 4512 4127 4068 4244 4267 4251 4146)
-#endif
-#include <google/protobuf/message.h>
-#ifdef _MSC_VER
-#pragma warning(pop)
-#endif
-
 #include <string>
 #include <map>
 #include <memory>
 #include <vector>
 
 #include "gz/msgs/config.hh"
 #include "gz/msgs/Export.hh"
+#include "gz/msgs/detail/dynamic_message_cast.hh"
 
 namespace gz
 {
   namespace msgs
   {
     // Inline bracket to help doxygen filtering.
     inline namespace GZ_MSGS_VERSION_NAMESPACE {
-    //
-    /// \typedef FactoryFn
-    /// \brief Prototype for message factory generation
-    typedef std::unique_ptr<google::protobuf::Message> (*FactoryFn) ();
-
     /// \class Factory Factory.hh gz/msgs.hh
+  /// This class  will also try to load all Protobuf descriptors specified
     /// \brief A factory that generates protobuf message based on a string type.
-    /// This class  will also try to load all Protobuf descriptors specified
     /// in the GZ_DESCRIPTOR_PATH environment variable on program start.
+
     class GZ_MSGS_VISIBLE Factory
     {
+      public: using Message = google::protobuf::Message;
+      public: using MessagePtr = std::unique_ptr<Message>;
+      public: using FactoryFn =
+        std::function<MessagePtr(void)>;
+
       /// \brief Register a message.
       /// \param[in] _msgType Type of message to register.
       /// \param[in] _factoryfn Function that generates the message.
-      public: static void Register(const std::string &_msgType,
-                                   FactoryFn _factoryfn);
+      public: static void
+              Register(const std::string &_msgType, FactoryFn _factoryFn);
 
       /// \brief Create a new instance of a message.
       /// \param[in] _msgType Type of message to create.
@@ -64,16 +57,7 @@ namespace gz
       public: template<typename T>
               static std::unique_ptr<T> New(const std::string &_msgType)
               {
-                auto msgType = _msgType;
-                if (msgType.find("ignition") == 0)
-                {
-                  msgType.replace(0, 8, "gz");
-                  std::cerr << "Trying to create deprecated message type ["
-                            << _msgType << "]. Using [" << msgType
-                            << "] instead." << std::endl;
-                }
-                return std::unique_ptr<T>(
-                    static_cast<T*>(New(msgType).release()));
+                return detail::dynamic_message_cast<T>(New(_msgType));
               }
 
       /// \brief Create a new instance of a message.
@@ -85,32 +69,23 @@ namespace gz
               static std::unique_ptr<T> New(const std::string &_msgType,
                   const std::string &_args)
               {
-                auto msgType = _msgType;
-                if (msgType.find("ignition") == 0)
-                {
-                  msgType.replace(0, 8, "gz");
-                  std::cerr << "Trying to create deprecated message type ["
-                            << _msgType << "]. Using [" << msgType
-                            << "] instead." << std::endl;
-                }
-                return std::unique_ptr<T>(
-                    static_cast<T*>(New(msgType, _args).release()));
+                return detail::dynamic_message_cast<T>(New(_msgType, _args));
               }
 
       /// \brief Create a new instance of a message.
       /// \param[in] _msgType Type of message to create.
       /// \return Pointer to a google protobuf message. Null if the message
       /// type could not be handled.
-      public: static std::unique_ptr<google::protobuf::Message> New(
-                  const std::string &_msgType);
+      public: static MessagePtr
+              New(const std::string &_msgType);
 
       /// \brief Create a new instance of a message.
       /// \param[in] _msgType Type of message to create.
       /// \param[in] _args Message arguments. This will populate the message.
       /// \return Pointer to a google protobuf message. Null if the message
       /// type could not be handled.
-      public: static std::unique_ptr<google::protobuf::Message> New(
-                  const std::string &_msgType, const std::string &_args);
+      public: static MessagePtr
+              New(const std::string &_msgType, const std::string &_args);
 
       /// \brief Get all the message types
       /// \param[out] _types Vector of strings of the message types.
@@ -120,9 +95,6 @@ namespace gz
       /// \param[in] _paths A set of directories containing .desc decriptor
       /// files. Each directory should be separated by ":".
       public: static void LoadDescriptors(const std::string &_paths);
-
-      /// \brief A list of registered message types
-      private: static std::map<std::string, FactoryFn> *msgMap;
     };
 
     /// \brief Static message registration macro
@@ -132,7 +104,7 @@ namespace gz
     /// \param[in] _classname Class name for message.
     #define GZ_REGISTER_STATIC_MSG(_msgtype, _classname) \
     GZ_MSGS_VISIBLE \
-    std::unique_ptr<google::protobuf::Message> New##_classname() \
+    gz::msgs::Factory::MessagePtr New##_classname() \
     { \
       return std::unique_ptr<gz::msgs::_classname>(\
           new gz::msgs::_classname); \

include/gz/msgs/MessageFactory.hh

@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2016 Open Source Robotics Foundation
+ *
+ * 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
+ *
+ *     http://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 GZ_MSGS_MESSAGE_FACTORY_HH_
+#define GZ_MSGS_MESSAGE_FACTORY_HH_
+
+#include <string>
+#include <map>
+#include <memory>
+#include <vector>
+
+#include "gz/msgs/config.hh"
+#include "gz/msgs/Export.hh"
+#include "gz/msgs/detail/dynamic_message_cast.hh"
+
+namespace gz::msgs {
+  /// Forward declarations
+  class DynamicFactory;
+
+  // Inline bracket to help doxygen filtering.
+  inline namespace GZ_MSGS_VERSION_NAMESPACE {
+
+  class GZ_MSGS_VISIBLE MessageFactory
+  {
+    public: using Message = google::protobuf::Message;
+    public: using MessagePtr = std::unique_ptr<Message>;
+    public: using FactoryFn = std::function<MessagePtr(void)>;
+
+    public: MessageFactory();
+
+    /// \brief Register a message.
+    /// \param[in] _msgType Type of message to register.
+    /// \param[in] _factoryfn Function that generates the message.
+    public: void Register(const std::string &_msgType, FactoryFn _factoryFn);
+
+    /// \brief Create a new instance of a message.
+    /// \param[in] _msgType Type of message to create.
+    /// \return Pointer to a google protobuf message. Null if the message
+    /// type could not be handled.
+    public: template<typename T>
+            std::unique_ptr<T> New(const std::string &_msgType)
+            {
+              return detail::dynamic_message_cast<T>(New(_msgType));
+            }
+
+    /// \brief Create a new instance of a message.
+    /// \param[in] _msgType Type of message to create.
+    /// \param[in] _args Message arguments. This will populate the message.
+    /// \return Pointer to a google protobuf message. Null if the message
+    /// type could not be handled.
+    public: template<typename T>
+            std::unique_ptr<T> New(const std::string &_msgType,
+                const std::string &_args)
+            {
+              return detail::dynamic_message_cast<T>(New(_msgType, _args));
+            }
+
+    /// \brief Create a new instance of a message.
+    /// \param[in] _msgType Type of message to create.
+    /// \return Pointer to a google protobuf message. Null if the message
+    /// type could not be handled.
+    public: MessagePtr New(const std::string &_msgType);
+
+    /// \brief Create a new instance of a message.
+    /// \param[in] _msgType Type of message to create.
+    /// \param[in] _args Message arguments. This will populate the message.
+    /// \return Pointer to a google protobuf message. Null if the message
+    /// type could not be handled.
+    public: MessagePtr New(
+                const std::string &_msgType, const std::string &_args);
+
+    /// \brief Get all the message types
+    /// \param[out] _types Vector of strings of the message types.
+    public: void Types(std::vector<std::string> &_types);
+
+    /// \brief Load a collection of descriptor .desc files.
+    /// \param[in] _paths A set of directories containing .desc decriptor
+    /// files. Each directory should be separated by ":".
+    public: void LoadDescriptors(const std::string &_paths);
+
+    /// \brief A list of registered message types
+    private: std::map<std::string, FactoryFn> msgMap;
+
+    private: std::unique_ptr<DynamicFactory> dynamicFactory;
+  };
+}
+}  // namespace gz::msgs
+#endif  // GZ_MSGS_MESSAGE_FACTORY_HH_

include/gz/msgs/detail/dynamic_message_cast.hh

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2023 Open Source Robotics Foundation
+ *
+ * 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
+ *
+ *     http://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 GZ_MSGS_DETAIL_DYNAMIC_POINTER_CAST_HH_
+#define GZ_MSGS_DETAIL_DYNAMIC_POINTER_CAST_HH_
+
+#include <memory>
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable: 4100 4512 4127 4068 4244 4267 4251 4146)
+#endif
+#include <google/protobuf/message.h>
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+namespace gz::msgs::detail
+{
+
+/// Cast a base unique pointer to protobuf message type to child type
+template<typename MsgT>
+std::unique_ptr<MsgT>
+dynamic_message_cast(std::unique_ptr<google::protobuf::Message> &&_baseMsg)
+{
+  auto converted = std::unique_ptr<MsgT>{dynamic_cast<MsgT*>(_baseMsg.get())};
+  if (converted) {
+    (void) _baseMsg.release();
+  }
+  return converted;
+}
+
+}  // namespace gz::msgs::detail
+
+#endif  // GZ_MSGS_DETAIL_DYNAMIC_POINTER_CAST_HH_

src/CMakeLists.txt

@@ -214,8 +214,9 @@ gz_install_includes(
 # Build the main library
 gz_create_core_library(SOURCES
   ${gen_sources}
+  ${PROJECT_SOURCE_DIR}/src/DynamicFactory.cc
   ${PROJECT_SOURCE_DIR}/src/Factory.cc
-  ${PROJECT_SOURCE_DIR}/src/Filesystem.cc
+  ${PROJECT_SOURCE_DIR}/src/MessageFactory.cc
   ${PROJECT_SOURCE_DIR}/src/gz.cc
   ${PROJECT_SOURCE_DIR}/src/Utility.cc
 )