add a NngServerSink and somehow get the plugin to link

Things are messy, doesn't link with clang in vscode, works in the shell.

CMakeLists.txt

@@ -16,6 +16,7 @@ set(CMAKE_VERBOSE_MAKEFILE ON CACHE BOOL "ON")
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
 option(MNODE_BUILD_TESTS "Build mnode test binaries" ${MESYTEC_MNODE_MAIN_PROJECT})
 

src/CMakeLists.txt

@@ -1,5 +1,11 @@
 set(MVLC_NNG_MNODE_WARN_FLAGS -Wall -Wextra -Wpedantic -Werror=return-type)
 
+add_library(mesytec-mnode-nng mnode_nng.cc)
+target_include_directories(mesytec-mnode-nng
+    PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../include>
+    PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/mesytec-mnode)
+target_link_libraries(mesytec-mnode-nng PUBLIC nng PRIVATE spdlog)
+
 add_library(mesytec-mnode mnode_nng.cc mnode_nng_async.cc mnode_nng_proto.cc)
 target_include_directories(mesytec-mnode
     PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../include>
@@ -10,6 +16,9 @@ target_compile_options(mesytec-mnode PRIVATE ${MVLC_NNG_MNODE_WARN_FLAGS})
 
 add_library(mana INTERFACE)
 target_link_libraries(mana INTERFACE nlohmann_json::nlohmann_json mesytec-mvlc)
+target_include_directories(mana
+    INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../include>
+    INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/mesytec-mnode>)
 
 add_subdirectory(tools)
 
@@ -47,3 +56,6 @@ if (pybind11_FOUND)
     target_link_libraries(mana-plugin-python PRIVATE mana mesytec-mnode rxi-logc pybind11::embed)
     file(CREATE_LINK ${CMAKE_CURRENT_SOURCE_DIR}/mana_python_test_plugin.py ${CMAKE_BINARY_DIR}/mana_python_test_plugin.py COPY_ON_ERROR SYMBOLIC)
 endif()
+
+add_library(mana-plugin-nng-server SHARED mana_plugin_nng_server.cc)
+target_link_libraries(mana-plugin-nng-server PRIVATE mesytec-mnode-nng mana rxi-logc)

src/internal/mana_nng.hpp

@@ -7,11 +7,32 @@
 namespace mesytec::mnode::mana
 {
 
-class NngServer: public IManaSink
+struct MessageHeader
+{
+    enum MessageType
+    {
+        BeginRun,
+        EndRun,
+        EventData,
+    };
+
+    u32 messageType;
+};
+
+// TODO: don't need sizeBytes as the client can infer from the descriptor in begin_run()
+// could transmit eventindex and array count as u16|u16 or sequence number and eventindex
+struct EventDataHeader
+{
+    u32 eventIndex;
+    u32 sizeBytes;
+};
+
+class NngServerSink: public IManaSink
 {
   public:
-    explicit NngServer(nng_socket socket)
+    explicit NngServerSink(nng_socket socket)
         : socket_(socket)
+        , msg_(nng::make_unique_msg())
     {
     }
 
@@ -21,19 +42,110 @@ class NngServer: public IManaSink
         (void)plugin_argv;
     }
 
-    void shutdown() override { nng_close(socket_); }
+    void shutdown() override {}
 
-    void begin_run(const char *descriptor_json) override { (void)descriptor_json; }
+    void begin_run(const char *descriptor_json) override
+    {
+        auto len = std::strlen(descriptor_json);
+        auto required = sizeof(MessageHeader) + len + 1;
+        auto msg = nng::allocate_message(required);
+        MessageHeader header{MessageHeader::BeginRun};
+        nng_msg_append(msg.get(), &header, sizeof(header));
+        nng_msg_append(msg.get(), descriptor_json, len + 1);
 
-    void end_run(const char *descriptor_json) override { (void)descriptor_json; }
+        spdlog::info("Sending BeginRun message");
+        int res = 0;
+
+        do
+        {
+            if ((res = nng::send_message(socket_, msg)))
+            {
+                if (res != NNG_ETIMEDOUT)
+                {
+                    nng::mnode_nng_error("nng_sendmsg", res);
+                    return;
+                }
+            }
+        }
+        while (res == NNG_ETIMEDOUT);
+
+        spdlog::info("Waiting for response from client");
+
+        while (true)
+        {
+            auto [msg, res] = nng::receive_message(socket_);
+
+            if (res && res != NNG_ETIMEDOUT)
+            {
+                nng::mnode_nng_error("nng_recvmsg", res);
+                return;
+            }
+            else if (!res)
+                break;
+        }
+    }
+
+    void end_run(const char *descriptor_json) override
+    {
+        auto len = std::strlen(descriptor_json);
+        auto required = sizeof(MessageHeader) + len + 1;
+        auto msg = nng::allocate_message(required);
+        MessageHeader header{MessageHeader::EndRun};
+        nng_msg_append(msg.get(), &header, sizeof(header));
+        nng_msg_append(msg.get(), descriptor_json, len + 1);
+        spdlog::info("Sending EndRun message");
+        int res = 0;
+
+        do
+        {
+            if ((res = nng::send_message(socket_, msg)))
+            {
+                if (res != NNG_ETIMEDOUT)
+                {
+                    nng::mnode_nng_error("nng_sendmsg", res);
+                    return;
+                }
+            }
+        }
+        while (res == NNG_ETIMEDOUT);
+    }
 
     void process_event(uint16_t eventIndex, mana_offset_array_t *arrays, size_t arrayCount,
                        size_t totalBytes) override
     {
-        (void)eventIndex;
-        (void)arrays;
-        (void)arrayCount;
-        (void)totalBytes;
+        if (!msg_)
+        {
+            msg_ = nng::allocate_reserve_message(InitialMessageReserve);
+            MessageHeader header{MessageHeader::EventData};
+            nng_msg_append(msg_.get(), &header, sizeof(header));
+        }
+
+        const size_t required = sizeof(EventDataHeader) + totalBytes;
+
+        if (nng::allocated_free_space(msg_.get()) < required &&
+            nng_msg_len(msg_.get()) > sizeof(MessageHeader))
+        {
+            if (!flush())
+                return;
+
+            assert(!msg_);
+            msg_ = nng::allocate_reserve_message(InitialMessageReserve);
+            MessageHeader header{MessageHeader::EventData};
+            nng_msg_append(msg_.get(), &header, sizeof(header));
+        }
+
+        // second check in case the event is larger than the initial reserve
+        if (nng::allocated_free_space(msg_.get()) < required)
+            nng_msg_reserve(msg_.get(), required);
+
+        assert(nng::allocated_free_space(msg_.get()) >= required);
+        assert(nng_msg_len(msg_.get()) >= sizeof(MessageHeader));
+
+        EventDataHeader header{};
+        header.eventIndex = eventIndex;
+        header.sizeBytes = totalBytes;
+        nng_msg_append(msg_.get(), &header, sizeof(header));
+        nng_msg_append(msg_.get(), arrays, totalBytes);
     }
 
     void process_system_event(const uint32_t *data, size_t size) override
@@ -43,7 +155,33 @@ class NngServer: public IManaSink
     }
 
   private:
+    bool flush()
+    {
+        if (!msg_)
+            return false;
+
+        spdlog::info("Sending EventData message of size {}", nng_msg_len(msg_.get()));
+
+        while (true)
+        {
+            if (auto res = nng::send_message(socket_, msg_))
+            {
+                if (res != NNG_ETIMEDOUT)
+                {
+                    nng::mnode_nng_error("nng_sendmsg", res);
+                    return false;
+                }
+            }
+            else
+                break;
+        }
+
+        return true;
+    }
+
+    static constexpr size_t InitialMessageReserve = 2 * 1024 * 1024;
     nng_socket socket_;
+    nng::unique_msg msg_;
 };
 
 } // namespace mesytec::mnode::mana

src/mana_plugin_nng_server.cc

@@ -0,0 +1,56 @@
+#include "internal/mana_nng.hpp"
+#include "internal/rxi/log.hpp"
+
+using namespace mesytec::mnode;
+using namespace mesytec::mnode::mana;
+
+class Plugin: public IManaPlugin
+{
+  public:
+    explicit Plugin(nng_socket socket)
+        : socket_(socket)
+    {
+    }
+
+    ~Plugin() override
+    {
+#if 0
+        if (nng_socket_id(socket_) >= 0)
+        {
+            nng_close(socket_);
+            socket_ = NNG_SOCKET_INITIALIZER;
+        }
+#endif
+    }
+
+    std::unique_ptr<IManaSink> makeSink() override
+    {
+        return std::make_unique<NngServerSink>(socket_);
+    }
+
+  private:
+    nng_socket socket_;
+};
+
+MANA_CPP_PLUGIN()
+{
+    static Plugin *plugin;
+    static const char *listenUrl = "ipc://mana_nng_server.socket";
+
+    if (plugin)
+    {
+        log_warn("plugin already created");
+        return plugin;
+    }
+
+    nng_socket socket = nng::make_pair_socket();
+    if (int res = nng_listen(socket, listenUrl, nullptr, 0))
+    {
+        nng::mnode_nng_error("nng_listen", res);
+        return nullptr;
+    }
+
+    log_info("listening on %s", listenUrl);
+
+    return plugin = new Plugin(socket);
+}