Implement effSetChunk

README.md

@@ -17,13 +17,6 @@ There are a few things that should be done before making this public, including:
   thing.
 - Fix `processReplacing` forwarding.
 - Implement GUIs.
-- Chunks. For `effSetChunk` we can now just use the strings. For `effGetChunk`
-  we need to find a clean way to 1. make the returned string exactly `n` bytes
-  long, where `n` is the value returned by the VST plugin's `dispatch()`
-  function (could be an option for `WritableBuffer`), and 2. store the returned
-  data in a `std::vector<uint8_t>` on the `HostBridge` struct and write back a
-  pointer to that instead. That might involve extending `DefaultDataConverter`
-  to also handle writing back values.
 - Check if we need special handling for the `effGetChunk` and `effSetChunk`
   events.
 - Mention precompiled binaries and building from source in the installation

src/common/communication.h

@@ -116,7 +116,9 @@ inline T read_object(Socket& socket) {
  */
 class DefaultDataConverter {
    public:
-    EventPayload read(const int /*opcode*/, const void* data) {
+    virtual ~DefaultDataConverter() {};
+
+    virtual EventPayload read(const int /*opcode*/, const intptr_t /*value*/, const void* data) {
         if (data == nullptr) {
             return nullptr;
         }
@@ -130,7 +132,7 @@ class DefaultDataConverter {
         }
     }
 
-    void write(const int /*opcode*/, void* data, const EventResult& response) {
+    virtual void write(const int /*opcode*/, void* data, const EventResult& response) {
         if (response.data.has_value()) {
             char* output = static_cast<char*>(data);
 
@@ -173,7 +175,7 @@ intptr_t send_event(boost::asio::local::stream_protocol::socket& socket,
                     std::optional<std::pair<Logger&, bool>> logging) {
     // Encode the right payload type for this event. Check the documentation for
     // `EventPayload` for more information.
-    const EventPayload payload = data_converter.read(opcode, data);
+    const EventPayload payload = data_converter.read(opcode, value, data);
 
     if (logging.has_value()) {
         auto [logger, is_dispatch] = *logging;

src/plugin/host-bridge.cpp

@@ -142,18 +142,24 @@ class DispatchDataConverter : DefaultDataConverter {
     DispatchDataConverter(std::vector<uint8_t>& chunk_data)
         : chunk(chunk_data) {}
 
-    EventPayload read(const int opcode, const void* data) {
+    EventPayload read(const int opcode, const intptr_t value, const void* data) {
         // There are some events that need specific structs that we can't simply
         // serialize as a string because they might contain null bytes
         // TODO: More of these structs
         switch (opcode) {
             case effGetChunk:
                 return WantsChunkBuffer();
+                break;
+            case effSetChunk:
+                // When the host passes a chunk it will use the value parameter
+                // to tell us its length
+                return std::string(static_cast<const char*>(data), value);
+                break;
             case effProcessEvents:
                 return DynamicVstEvents(*static_cast<const VstEvents*>(data));
                 break;
             default:
-                return DefaultDataConverter::read(opcode, data);
+                return DefaultDataConverter::read(opcode, value, data);
                 break;
         }
     }