WIP: Add C++ bindings

CMakeLists.txt

@@ -19,6 +19,7 @@ option(NATS_BUILD_WITH_TLS "Build with TLS support" ON)
 option(NATS_BUILD_TLS_FORCE_HOST_VERIFY "Forces hostname verification" ON)
 option(NATS_BUILD_TLS_USE_OPENSSL_1_1_API "Build for OpenSSL 1.1+" OFF)
 option(NATS_BUILD_USE_SODIUM "Build using libsodium library" OFF)
+option(NATS_BUILD_CPP_BINDINGS "Build binding for C++" OFF)
 option(NATS_BUILD_EXAMPLES "Build examples" ON)
 option(NATS_BUILD_LIBUV_EXAMPLE "Build libuv examples" OFF)
 option(NATS_BUILD_LIBEVENT_EXAMPLE "Build libevent examples" OFF)
@@ -51,6 +52,10 @@ if(NATS_BUILD_WITH_TLS_CLIENT_METHOD)
   set(NATS_BUILD_TLS_USE_OPENSSL_1_1_API ON)
 endif(NATS_BUILD_WITH_TLS_CLIENT_METHOD)
 
+if(NATS_BUILD_CPP_BINDINGS)
+  find_package(Python3 REQUIRED)
+endif(NATS_BUILD_CPP_BINDINGS)
+
 set(LIBUV_DIR "/usr/local/" CACHE PATH "Libuv install directory")
 set(LIBEVENT_DIR "/usr/local/" CACHE PATH "Libevent install directory")
 
@@ -259,6 +264,9 @@ add_subdirectory(examples/getstarted)
 if(NATS_BUILD_STREAMING)
   add_subdirectory(examples/stan)
 endif()
+if(NATS_BUILD_CPP_BINDINGS)
+  add_subdirectory(examples/cpp)
+endif()
 add_subdirectory(test)
 add_subdirectory(test/dylib)
 #----------------------------

examples/cpp/CMakeLists.txt

@@ -0,0 +1,34 @@
+if(NOT NATS_BUILD_EXAMPLES)
+  return()
+endif()
+
+# We need this directory to build the examples
+include_directories(${PROJECT_SOURCE_DIR}/src)
+include_directories(${PROJECT_SOURCE_DIR}/examples/cpp)
+include_directories(${CMAKE_BINARY_DIR}/src)
+
+# Get all the .cpp files in the examples directory
+file(GLOB EXAMPLES_SOURCES RELATIVE ${PROJECT_SOURCE_DIR}/examples/cpp *.cpp)
+
+if(NOT NATS_BUILD_STATIC_EXAMPLES)
+  add_definitions(-Dnats_IMPORTS)
+endif()
+
+# For each file...
+foreach(examples_src ${EXAMPLES_SOURCES})
+
+    # Remove the suffix so that it becomes the executable name
+    string(REPLACE ".cpp" "" examplename ${examples_src})
+    set(exampleexe "nats-cpp-${examplename}")
+
+    # Build the executable
+    add_executable(${exampleexe} ${PROJECT_SOURCE_DIR}/examples/cpp/${examples_src})
+
+    # Link
+    if(NATS_BUILD_STATIC_EXAMPLES)
+      target_link_libraries(${exampleexe} nats_static ${NATS_EXTRA_LIB})
+    else()
+      target_link_libraries(${exampleexe} nats ${NATS_EXTRA_LIB})
+    endif()
+
+endforeach()

examples/cpp/subscriber.cpp

@@ -0,0 +1,65 @@
+// Copyright 2015-2020 The NATS Authors
+// 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.
+
+#include "nats.hpp"
+#include <iostream>
+
+class ErrHandler {
+public:
+    ErrHandler(const char* id) : id_(id) {}
+
+    void handle(nats::Connection & nc, nats::Subscription & sub, natsStatus err)
+    {
+        std::cout << id_ << " error:" << nats::GetText(err) << std::endl;
+    }
+
+private:
+    const char* id_;
+};
+
+class Handler {
+public:
+    Handler(const char* id) : id_(id) {}
+
+    void msg(nats::Connection & nc, nats::Subscription & sub, nats::Msg && msg)
+    {
+        std::string data(msg.GetData(), msg.GetDataLength());
+        std::cout << id_ << " received: " << msg.GetSubject() << " - " << data << std::endl;
+    }
+
+private:
+    const char* id_;
+};
+
+int main(int argc, char **argv)
+{
+    Handler hh("HandlerId");
+    ErrHandler eh("MyErrorHandler");
+
+    nats::Open(10);
+
+    nats::Options options;
+    options.SetErrorHandler<ErrHandler, &ErrHandler::handle>(&eh);
+
+    nats::Connection connection(options);
+    nats::Subscription sub = connection.Subscribe<Handler, &Handler::msg>("subject", &hh);
+
+    nats::Statistics stat;
+
+    for (;;)
+        nats::Sleep(1000);
+
+    nats::Close();
+
+    return 0;
+}

src/CMakeLists.txt

@@ -50,6 +50,25 @@ if(NATS_BUILD_LIB_STATIC)
   target_compile_definitions(nats_static PRIVATE -DNATS_STATIC)
 endif(NATS_BUILD_LIB_STATIC)
 
+# ---------------------------
+# Create the bindings for C++
+# ---------------------------
+if(NATS_BUILD_CPP_BINDINGS)
+  add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/nats.hpp
+        COMMAND ${Python3_EXECUTABLE}
+          bindings/cpp_generator.py
+          bindings/cpp_template.mako
+          nats.h
+          ${CMAKE_CURRENT_BINARY_DIR}/nats.hpp
+        DEPENDS
+          bindings/cpp_generator.py
+          bindings/cpp_template.mako
+          nats.h
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
+  add_custom_target(nats_cpp_bindings ALL DEPENDS ${CMAKE_BINARY_DIR}/nats.hpp)
+  install(FILES ${CMAKE_CURRENT_BINARY_DIR}/nats.hpp DESTINATION ${NATS_INCLUDE_DIR}/nats)
+endif(NATS_BUILD_CPP_BINDINGS)
+
 # --------------------------------------
 # Install the libraries and header files
 # --------------------------------------