Work around improperly late initializing plugins

This fixes the Roland Cloud plugins.

CHANGELOG.md

@@ -6,6 +6,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic
 Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- Added a workaround for plugins that improperly defer part of their
+  initialization process without telling the host. This fixes the Roland Cloud
+  plugins.
+
 ## [1.1.2] - 2020-05-09
 
 ### Fixed

src/common/events.h

@@ -283,6 +283,14 @@ auto passthrough_event(AEffect* plugin, F callback) {
             [&](DynamicSpeakerArrangement& speaker_arrangement) -> void* {
                 return &speaker_arrangement.as_c_speaker_arrangement();
             },
+            [&](WantsAEffectUpdate&) -> void* {
+                // The host will never actually ask for an updated `AEffect`
+                // object since that should not be a thing. This is purely a
+                // meant as a workaround for plugins that initialize their
+                // `AEffect` object after the plugin has already finished
+                // initializing.
+                return nullptr;
+            },
             [&](WantsChunkBuffer&) -> void* { return string_buffer.data(); },
             [&](VstIOProperties& props) -> void* { return &props; },
             [&](VstMidiKeyName& key_name) -> void* { return &key_name; },
@@ -335,6 +343,7 @@ auto passthrough_event(AEffect* plugin, F callback) {
             [&](VstParameterProperties& props) -> EventResultPayload {
                 return props;
             },
+            [&](WantsAEffectUpdate&) -> EventResultPayload { return *plugin; },
             [&](WantsVstRect&) -> EventResultPayload {
                 // The plugin has written a pointer to a VstRect struct into the
                 // data poitner

src/common/logging.cpp

@@ -201,14 +201,15 @@ void Logger::log_event(bool is_dispatch,
                     message << "<" << speaker_arrangement.speakers.size()
                             << " output_speakers>";
                 },
-                [&](const WantsChunkBuffer&) {
-                    message << "<writable_buffer>";
-                },
                 [&](const VstIOProperties&) { message << "<io_properties>"; },
                 [&](const VstMidiKeyName&) { message << "<key_name>"; },
                 [&](const VstParameterProperties&) {
                     message << "<writable_buffer>";
                 },
+                [&](const WantsAEffectUpdate&) { message << "<nullptr>"; },
+                [&](const WantsChunkBuffer&) {
+                    message << "<writable_buffer>";
+                },
                 [&](const WantsVstRect&) { message << "<writable_buffer>"; },
                 [&](const WantsVstTimeInfo&) { message << "<nullptr>"; },
                 [&](const WantsString&) { message << "<writable_string>"; }},

src/common/serialization.h

@@ -285,6 +285,15 @@ class alignas(16) DynamicSpeakerArrangement {
     std::vector<uint8_t> speaker_arrangement_buffer;
 };
 
+/**
+ * Marker struct to indicate that the other side (the Wine VST host) should send
+ * an updated copy of the plugin's `AEffect` object. Should not be needed since
+ * the plugin should be calling `audioMasterIOChanged()` after it has changed
+ * its object, but some improperly coded plugins will only initialize their
+ * flags, IO properties and parameter counts after `effEditOpen()`.
+ */
+struct WantsAEffectUpdate {};
+
 /**
  * Marker struct to indicate that that the event writes arbitrary data into one
  * of its own buffers and uses the void pointer to store start of that data,
@@ -352,6 +361,7 @@ using EventPayload = std::variant<std::nullptr_t,
                                   AEffect,
                                   DynamicVstEvents,
                                   DynamicSpeakerArrangement,
+                                  WantsAEffectUpdate,
                                   WantsChunkBuffer,
                                   VstIOProperties,
                                   VstMidiKeyName,
@@ -382,8 +392,9 @@ void serialize(S& s, EventPayload& payload) {
               [](S& s, VstIOProperties& props) { s.object(props); },
               [](S& s, VstMidiKeyName& key_name) { s.object(key_name); },
               [](S& s, VstParameterProperties& props) { s.object(props); },
-              [](S&, WantsChunkBuffer&) {}, [](S&, WantsVstRect&) {},
-              [](S&, WantsVstTimeInfo&) {}, [](S&, WantsString&) {}});
+              [](S&, WantsAEffectUpdate&) {}, [](S&, WantsChunkBuffer&) {},
+              [](S&, WantsVstRect&) {}, [](S&, WantsVstTimeInfo&) {},
+              [](S&, WantsString&) {}});
 }
 
 /**

src/plugin/plugin-bridge.cpp

@@ -229,8 +229,9 @@ PluginBridge::PluginBridge(audioMasterCallback host_callback)
 class DispatchDataConverter : DefaultDataConverter {
    public:
     DispatchDataConverter(std::vector<uint8_t>& chunk_data,
+                          AEffect& plugin,
                           VstRect& editor_rectangle)
-        : chunk(chunk_data), rect(editor_rectangle) {}
+        : chunk(chunk_data), plugin(plugin), rect(editor_rectangle) {}
 
     EventPayload read(const int opcode,
                       const int index,
@@ -239,6 +240,13 @@ class DispatchDataConverter : DefaultDataConverter {
         // There are some events that need specific structs that we can't simply
         // serialize as a string because they might contain null bytes
         switch (opcode) {
+            case effOpen:
+                // This should not be needed, but some improperly coded plugins
+                // such as the Roland Cloud plugins will initialize part of
+                // their `AEffect` only after the host calls `effOpen`, instead
+                // of during the initialization.
+                return WantsAEffectUpdate{};
+                break;
             case effEditGetRect:
                 return WantsVstRect();
                 break;
@@ -325,6 +333,14 @@ class DispatchDataConverter : DefaultDataConverter {
 
     void write(const int opcode, void* data, const EventResult& response) {
         switch (opcode) {
+            case effOpen: {
+                // Update our `AEffect` object one last time for improperly
+                // coded late initialing plugins. Hopefully the host will see
+                // that the object is updated because these plugins don't send
+                // any notification about this.
+                const auto updated_plugin = std::get<AEffect>(response.payload);
+                update_aeffect(plugin, updated_plugin);
+            } break;
             case effEditGetRect: {
                 // Write back the (hopefully) updated editor dimensions
                 const auto new_rect = std::get<VstRect>(response.payload);
@@ -423,6 +439,7 @@ class DispatchDataConverter : DefaultDataConverter {
 
    private:
     std::vector<uint8_t>& chunk;
+    AEffect& plugin;
     VstRect& rect;
 };
 
@@ -449,7 +466,7 @@ intptr_t PluginBridge::dispatch(AEffect* /*plugin*/,
         return 0;
     }
 
-    DispatchDataConverter converter(chunk_data, editor_rectangle);
+    DispatchDataConverter converter(chunk_data, plugin, editor_rectangle);
 
     switch (opcode) {
         case effClose: {