(kinda) bring back extension proxy object support in AAPXSDefinition.

I thought we could just eliminate strongly typed extension proxies from
AAPXSDefinition.
It turned out that binder-client-as-plugin still needs to implement
`get_extension()` function, and it needs an extension instance for each URI.

The problem was hidden because `get_extension()` in binder-client-as-plugin
was buggy and was trying to get the extension from AndroidAudioPluginHost,
whose extension retrieval was also buggy and returned plugin extensions.

Fortunately?, TypedAAPXS classes could be used to represent the extension
functions and they could be kinda populated with additional contexts (such
as AAPXSInitiatorInstance and AAPXSSerialization).

androidaudioplugin/src/main/cpp/android/AudioPluginInterfaceImpl.h

@@ -115,6 +115,7 @@ class AudioPluginInterfaceImpl : public aidl::org::androidaudioplugin::BnAudioPl
         CHECK_INSTANCE(instance, in_instanceID)
 
         instance->completeInstantiation();
+        instance->setupAAPXS();
         instance->setupAAPXSInstances();
         instance->startPortConfiguration();
         return ndk::ScopedAStatus::ok();

androidaudioplugin/src/main/cpp/android/AudioPluginNatives_jni.cpp

@@ -166,7 +166,8 @@ Java_org_androidaudioplugin_hosting_NativeRemotePluginInstance_createRemotePlugi
 	}
 	auto instance = dynamic_cast<aap::RemotePluginInstance*>(client->getInstanceById(result.value));
 	assert(instance);
-	instance->configurePorts();
+    instance->scanParametersAndBuildList();
+    instance->configurePorts();
 	return (jlong) result.value;
 }
 

androidaudioplugin/src/main/cpp/android/binder-client-as-plugin.cpp

@@ -156,7 +156,13 @@ void aap_client_as_plugin_deactivate(AndroidAudioPlugin *plugin)
 void* aap_client_as_plugin_get_extension(AndroidAudioPlugin *plugin, const char *uri)
 {
 	auto ctx = (AAPClientContext*) plugin->plugin_specific;
-	return ctx->host.get_extension(&ctx->host, uri);
+    auto instance = (aap::RemotePluginInstance*) ctx->host.context;
+    auto aapxsDefinition = instance->getAAPXSRegistry()->items()->getByUri(uri);
+    if (!aapxsDefinition->get_plugin_extension_proxy)
+        return nullptr;
+    auto aapxsInstance = instance->getAAPXSDispatcher().getPluginAAPXSByUri(uri);
+    auto proxy = aapxsDefinition->get_plugin_extension_proxy(aapxsDefinition, aapxsInstance, aapxsInstance->serialization);
+    return proxy.as_plugin_extension(&proxy);
 }
 
 aap_plugin_info_t aap_client_as_plugin_get_plugin_info(AndroidAudioPlugin *plugin)
@@ -214,7 +220,7 @@ AndroidAudioPlugin* aap_client_as_plugin_new(
 
         // Set up shared memory FDs for plugin extension services.
         // We make use of plugin metadata that should list up required and optional extensions.
-        if (!instance->setupAAPXSInstances(instance->getAAPXSRegistry(), [&](const char* uri, AAPXSSerializationContext *serialization) {
+        if (!instance->setupAAPXSInstances([&](const char* uri, AAPXSSerializationContext *serialization) {
             // create asharedmem and add as an extension FD, keep it until it is destroyed.
             auto fd = ASharedMemory_create(nullptr, serialization->data_capacity);
             auto shm = instance->getSharedMemoryStore();

androidaudioplugin/src/main/cpp/core/aapxs/aapxs-runtime.cpp

@@ -4,8 +4,8 @@
 
 // Client setup
 
-aap::xs::AAPXSClientDispatcher::AAPXSClientDispatcher(AAPXSDefinitionClientRegistry *registry)
-        : AAPXSDispatcher(registry->items()->getUridMapping()), registry(registry) {
+aap::xs::AAPXSClientDispatcher::AAPXSClientDispatcher(AAPXSDefinitionRegistry *registry)
+        : AAPXSDispatcher(registry->getUridMapping()), registry(registry) {
 }
 
 bool aap::xs::AAPXSClientDispatcher::setupInstances(void* hostContext,
@@ -15,11 +15,10 @@ bool aap::xs::AAPXSClientDispatcher::setupInstances(void* hostContext,
                                                     initiator_get_new_request_id_func initiatorGetNewRequestId) {
     assert(!already_setup);
 
-    auto items = registry->items();
-    if (!std::all_of(items->begin(), items->end(), [&](AAPXSDefinition& f) {
+    if (!std::all_of(registry->begin(), registry->end(), [&](AAPXSDefinition& f) {
         if (!f.uri)
             return true; // skip
-        int32_t urid = registry->items()->getUridMapping()->getUrid(f.uri);
+        int32_t urid = registry->getUridMapping()->getUrid(f.uri);
         // allocate SerializationContext
         auto serialization = std::make_unique<AAPXSSerializationContext>();
         serialization->data_capacity = f.data_capacity;
@@ -63,14 +62,14 @@ aap::xs::AAPXSClientDispatcher::populateAAPXSRecipientInstance(
 }
 
 AAPXSSerializationContext *aap::xs::AAPXSClientDispatcher::getSerialization(const char *uri) {
-    auto& shm = serialization_store[registry->items()->getUridMapping()->getUrid(uri)];
+    auto& shm = serialization_store[registry->getUridMapping()->getUrid(uri)];
     return shm ? shm.get() : nullptr;
 }
 
 // Service setup
 
-aap::xs::AAPXSServiceDispatcher::AAPXSServiceDispatcher(AAPXSDefinitionServiceRegistry *registry)
-        : AAPXSDispatcher(registry->items()->getUridMapping()), registry(registry) {
+aap::xs::AAPXSServiceDispatcher::AAPXSServiceDispatcher(AAPXSDefinitionRegistry *registry)
+        : AAPXSDispatcher(registry->getUridMapping()), registry(registry) {
 }
 
 void aap::xs::AAPXSServiceDispatcher::setupInstances(void* hostContext,
@@ -80,11 +79,10 @@ void aap::xs::AAPXSServiceDispatcher::setupInstances(void* hostContext,
                                                      initiator_get_new_request_id_func initiatorGetNewRequestId) {
     assert(!already_setup);
 
-    auto items = registry->items();
-    std::for_each(items->begin(), items->end(), [&](AAPXSDefinition& f) {
+    std::for_each(registry->begin(), registry->end(), [&](AAPXSDefinition& f) {
         if (!f.uri)
             return; // skip
-        int32_t urid = registry->items()->getUridMapping()->getUrid(f.uri);
+        int32_t urid = registry->getUridMapping()->getUrid(f.uri);
         // allocate SerializationContext
         auto serialization = std::make_unique<AAPXSSerializationContext>();
         // host extensions

androidaudioplugin/src/main/cpp/core/aapxs/midi-aapxs.cpp

@@ -41,6 +41,18 @@ void aap::xs::AAPXSDefinition_Midi::aapxs_midi_process_incoming_host_aapxs_reply
         request->callback(request->callback_user_data, host, request->request_id);
 }
 
-int32_t aap::xs::MidiClientAAPXS::getMidiMappingPolicy() {
-    return callTypedFunctionSynchronously<int32_t>(OPCODE_GET_MAPPING_POLICY);
+AAPXSExtensionClientProxy
+aap::xs::AAPXSDefinition_Midi::aapxs_midi_get_plugin_proxy(struct AAPXSDefinition *feature,
+                                                           AAPXSInitiatorInstance *aapxsInstance,
+                                                           AAPXSSerializationContext *serialization) {
+    auto client = (AAPXSDefinition_Midi*) feature->aapxs_context;
+    if (!client->typed_client)
+        client->typed_client = std::make_unique<MidiClientAAPXS>(aapxsInstance, serialization);
+    *client->typed_client = MidiClientAAPXS(aapxsInstance, serialization);
+    client->client_proxy = AAPXSExtensionClientProxy{client->typed_client.get(), aapxs_midi_as_plugin_extension};
+    return client->client_proxy;
+}
+
+enum aap_midi_mapping_policy aap::xs::MidiClientAAPXS::getMidiMappingPolicy() {
+    return callTypedFunctionSynchronously<enum aap_midi_mapping_policy>(OPCODE_GET_MAPPING_POLICY);
 }

androidaudioplugin/src/main/cpp/core/aapxs/parameters-aapxs.cpp

@@ -86,6 +86,28 @@ void aap::xs::AAPXSDefinition_Parameters::aapxs_parameters_process_incoming_host
         request->callback(request->callback_user_data, host, request->request_id);
 }
 
+AAPXSExtensionClientProxy aap::xs::AAPXSDefinition_Parameters::aapxs_parameters_get_plugin_proxy(
+        struct AAPXSDefinition *feature, AAPXSInitiatorInstance *aapxsInstance,
+        AAPXSSerializationContext *serialization) {
+    auto client = (AAPXSDefinition_Parameters*) feature->aapxs_context;
+    if (!client->typed_client)
+        client->typed_client = std::make_unique<ParametersClientAAPXS>(aapxsInstance, serialization);
+    *client->typed_client = ParametersClientAAPXS(aapxsInstance, serialization);
+    client->client_proxy = AAPXSExtensionClientProxy{client->typed_client.get(), aapxs_parameters_as_plugin_extension};
+    return client->client_proxy;
+}
+
+AAPXSExtensionServiceProxy aap::xs::AAPXSDefinition_Parameters::aapxs_parameters_get_host_proxy(
+        struct AAPXSDefinition *feature, AAPXSInitiatorInstance *aapxsInstance,
+        AAPXSSerializationContext *serialization) {
+    auto service = (AAPXSDefinition_Parameters*) feature->aapxs_context;
+    if (!service->typed_service)
+        service->typed_service = std::make_unique<ParametersServiceAAPXS>(aapxsInstance, serialization);
+    *service->typed_service = ParametersServiceAAPXS(aapxsInstance, serialization);
+    service->service_proxy = AAPXSExtensionServiceProxy{&service->typed_service, aapxs_parameters_as_host_extension};
+    return service->service_proxy;
+}
+
 // AAPXSParametersClient
 
 int32_t aap::xs::ParametersClientAAPXS::getParameterCount() {
@@ -95,26 +117,26 @@ int32_t aap::xs::ParametersClientAAPXS::getParameterCount() {
 aap_parameter_info_t aap::xs::ParametersClientAAPXS::getParameter(int32_t index) {
     *((int32_t*) serialization->data) = index;
     return callTypedFunctionSynchronously<aap_parameter_info_t>(
-            OPCODE_PARAMETERS_GET_PARAMETER_COUNT);
+            OPCODE_PARAMETERS_GET_PARAMETER);
 }
 
 double aap::xs::ParametersClientAAPXS::getProperty(int32_t index, int32_t propertyId) {
     *((int32_t*) serialization->data) = index;
     *((int32_t*) serialization->data + 1) = propertyId;
-    return callTypedFunctionSynchronously<double>(OPCODE_PARAMETERS_GET_PARAMETER_COUNT);
+    return callTypedFunctionSynchronously<double>(OPCODE_PARAMETERS_GET_PROPERTY);
 }
 
 int32_t aap::xs::ParametersClientAAPXS::getEnumerationCount(int32_t index) {
     *((int32_t*) serialization->data) = index;
-    return callTypedFunctionSynchronously<int32_t>(OPCODE_PARAMETERS_GET_PARAMETER_COUNT);
+    return callTypedFunctionSynchronously<int32_t>(OPCODE_PARAMETERS_GET_ENUMERATION_COUNT);
 }
 
 aap_parameter_enum_t
 aap::xs::ParametersClientAAPXS::getEnumeration(int32_t index, int32_t enumIndex) {
     *((int32_t*) serialization->data) = index;
     *((int32_t*) serialization->data + 1) = enumIndex;
     return callTypedFunctionSynchronously<aap_parameter_enum_t>(
-            OPCODE_PARAMETERS_GET_PARAMETER_COUNT);
+            OPCODE_PARAMETERS_GET_ENUMERATION);
 }
 
 void aap::xs::ParametersClientAAPXS::completeWithParameterCallback (void* callbackData, void* pluginOrHost, int32_t requestId) {

androidaudioplugin/src/main/cpp/core/aapxs/presets-aapxs.cpp

@@ -5,51 +5,52 @@ void aap::xs::AAPXSDefinition_Presets::aapxs_presets_process_incoming_plugin_aap
         struct AAPXSDefinition *feature, AAPXSRecipientInstance *aapxsInstance,
         AndroidAudioPlugin *plugin, AAPXSRequestContext *request) {
     auto ext = (aap_presets_extension_t*) plugin->get_extension(plugin, AAP_PRESETS_EXTENSION_URI);
-    if (!ext)
-        return; // FIXME: should there be any global error handling?
     switch(request->opcode) {
         case OPCODE_GET_PRESET_COUNT:
-            *((int32_t*) request->serialization->data) = ext->get_preset_count(ext, plugin);
+            *((int32_t*) request->serialization->data) = ext ? ext->get_preset_count(ext, plugin) : 0;
             // RT_SAFE. Send reply now.
             aapxsInstance->send_aapxs_reply(aapxsInstance, request);
             break;
         case OPCODE_GET_PRESET_INDEX:
-            *((int32_t*) request->serialization->data) = ext->get_preset_index(ext, plugin);
+            *((int32_t*) request->serialization->data) = ext ? ext->get_preset_index(ext, plugin) : 0;
             // RT_SAFE. Send reply now.
             aapxsInstance->send_aapxs_reply(aapxsInstance, request);
             break;
         case OPCODE_SET_PRESET_INDEX: {
-            int32_t index = *((int32_t *) request->serialization->data);
+            if (ext) {
+                int32_t index = *((int32_t *) request->serialization->data);
 
-            // FIXME: should this be calling it asynchronously?
-            //  Async invoker foundation should be backed by AAPXSRecipientInstance though.
+                // FIXME: should this be calling it asynchronously?
+                //  Async invoker foundation should be backed by AAPXSRecipientInstance though.
 
-            ext->set_preset_index(ext, plugin, index);
+                ext->set_preset_index(ext, plugin, index);
+            }
 
             aapxsInstance->send_aapxs_reply(aapxsInstance, request);
             break;
         }
         case OPCODE_GET_PRESET_DATA: {
-            // request (offset-range: content)
-            // - 0..3 : int32_t index
-            // - 4..7 : bool skip binary or not
-            aap_preset_t preset;
-            int32_t index = *((int32_t *) request->serialization->data);
-
-            // FIXME: should this be calling it asynchronously?
-            //  Async invoker foundation should be backed by AAPXSRecipientInstance though.
-
-            ext->get_preset(ext, plugin, index, &preset, nullptr,
-                            nullptr); // we can pass null callback as plugins implement it in synchronous way
-            // response (offset-range: content)
-            // - 0..3 : stable ID
-            // - 4..259 : name (fixed length char buffer)
-            *((int32_t *) request->serialization->data) = preset.id;
-            size_t len = strlen(preset.name);
-            strncpy((char *) request->serialization->data + sizeof(int32_t),
-                    const_cast<char *const>(preset.name), len);
-            ((char *) request->serialization->data)[len + sizeof(int32_t)] = 0;
-
+            if (ext) {
+                // request (offset-range: content)
+                // - 0..3 : int32_t index
+                // - 4..7 : bool skip binary or not
+                aap_preset_t preset;
+                int32_t index = *((int32_t *) request->serialization->data);
+
+                // FIXME: should this be calling it asynchronously?
+                //  Async invoker foundation should be backed by AAPXSRecipientInstance though.
+
+                ext->get_preset(ext, plugin, index, &preset, nullptr,
+                                nullptr); // we can pass null callback as plugins implement it in synchronous way
+                // response (offset-range: content)
+                // - 0..3 : stable ID
+                // - 4..259 : name (fixed length char buffer)
+                *((int32_t *) request->serialization->data) = preset.id;
+                size_t len = strlen(preset.name);
+                strncpy((char *) request->serialization->data + sizeof(int32_t),
+                        const_cast<char *const>(preset.name), len);
+                ((char *) request->serialization->data)[len + sizeof(int32_t)] = 0;
+            }
             aapxsInstance->send_aapxs_reply(aapxsInstance, request);
             break;
         }
@@ -90,6 +91,30 @@ void aap::xs::AAPXSDefinition_Presets::aapxs_presets_process_incoming_host_aapxs
         request->callback(request->callback_user_data, host, request->request_id);
 }
 
+AAPXSExtensionClientProxy
+aap::xs::AAPXSDefinition_Presets::aapxs_presets_get_plugin_proxy(struct AAPXSDefinition *feature,
+                                                                 AAPXSInitiatorInstance *aapxsInstance,
+                                                                 AAPXSSerializationContext *serialization) {
+    auto client = (AAPXSDefinition_Presets*) feature->aapxs_context;
+    if (!client->typed_client)
+        client->typed_client = std::make_unique<PresetsClientAAPXS>(aapxsInstance, serialization);
+    *client->typed_client = PresetsClientAAPXS(aapxsInstance, serialization);
+    client->client_proxy = AAPXSExtensionClientProxy{client->typed_client.get(), aapxs_presets_as_plugin_extension};
+    return client->client_proxy;
+}
+
+AAPXSExtensionServiceProxy
+aap::xs::AAPXSDefinition_Presets::aapxs_presets_get_host_proxy(struct AAPXSDefinition *feature,
+                                                               AAPXSInitiatorInstance *aapxsInstance,
+                                                               AAPXSSerializationContext *serialization) {
+    auto service = (AAPXSDefinition_Presets*) feature->aapxs_context;
+    if (!service->typed_service)
+        service->typed_service = std::make_unique<PresetsServiceAAPXS>(aapxsInstance, serialization);
+    *service->typed_service = PresetsServiceAAPXS(aapxsInstance, serialization);
+    service->service_proxy = AAPXSExtensionServiceProxy{&service->typed_service, aapxs_presets_as_host_extension};
+    return service->service_proxy;
+}
+
 // Strongly-typed client implementation (plugin extension functions)
 
 int32_t aap::xs::PresetsClientAAPXS::getPresetCount() {

androidaudioplugin/src/main/cpp/core/aapxs/state-aapxs.cpp

@@ -52,7 +52,19 @@ void aap::xs::AAPXSDefinition_State::aapxs_state_process_incoming_host_aapxs_rep
         request->callback(request->callback_user_data, host, request->request_id);
 }
 
-int32_t aap::xs::StateClientAAPXS::getStateSize() {
+AAPXSExtensionClientProxy
+aap::xs::AAPXSDefinition_State::aapxs_state_get_plugin_proxy(struct AAPXSDefinition *feature,
+                                                             AAPXSInitiatorInstance *aapxsInstance,
+                                                             AAPXSSerializationContext *serialization) {
+    auto client = (AAPXSDefinition_State*) feature->aapxs_context;
+    if (!client->typed_client)
+        client->typed_client = std::make_unique<StateClientAAPXS>(aapxsInstance, serialization);
+    *client->typed_client = StateClientAAPXS(aapxsInstance, serialization);
+    client->client_proxy = AAPXSExtensionClientProxy{client->typed_client.get(), aapxs_parameters_as_plugin_extension};
+    return client->client_proxy;
+}
+
+size_t aap::xs::StateClientAAPXS::getStateSize() {
     return callTypedFunctionSynchronously<int32_t>(OPCODE_GET_STATE_SIZE);
 }
 

androidaudioplugin/src/main/cpp/core/hosting/PluginHost.Client.cpp

@@ -77,8 +77,8 @@ aap::PluginClient::Result<int32_t> aap::PluginClient::instantiateRemotePlugin(co
                                                      descriptor, pluginFactory,
                                                      sampleRate, event_midi2_input_buffer_size);
             instances.emplace_back(instance);
+            instance->setupAAPXS();
             instance->completeInstantiation();
-            instance->scanParametersAndBuildList();
             return Result<int32_t>{instance->getInstanceId(), ""};
         }
         else

androidaudioplugin/src/main/cpp/core/hosting/PluginInstance.Local.cpp

@@ -21,7 +21,7 @@ aap::LocalPluginInstance::LocalPluginInstance(
           host(host),
           aapxs_host_session(eventMidi2InputBufferSize),
           feature_registry(new xs::AAPXSDefinitionServiceRegistry(aapxsRegistry)),
-          aapxs_dispatcher(xs::AAPXSServiceDispatcher(feature_registry.get()))
+          aapxs_dispatcher(aapxsRegistry)
           {
     shared_memory_store = new aap::ServicePluginSharedMemoryStore();
     instance_id = instanceId;

androidaudioplugin/src/main/cpp/core/hosting/PluginInstance.Remote.cpp

@@ -14,7 +14,7 @@ aap::RemotePluginInstance::RemotePluginInstance(PluginClient* client,
           client(client),
           aapxs_session(eventMidi2InputBufferSize),
           feature_registry(new xs::AAPXSDefinitionClientRegistry(aapxsRegistry)),
-          aapxs_dispatcher(xs::AAPXSClientDispatcher(feature_registry.get()))
+          aapxs_dispatcher(aapxsRegistry)
           {
     shared_memory_store = new ClientPluginSharedMemoryStore();
 
@@ -201,13 +201,15 @@ static inline void staticSendAAPXSReply(AAPXSRecipientInstance* instance, AAPXSR
     ((aap::RemotePluginInstance*) instance->host_context)->sendHostAAPXSReply(context);
 }
 
-bool aap::RemotePluginInstance::setupAAPXSInstances(xs::AAPXSDefinitionClientRegistry *registry,
-                                                    std::function<bool(const char*, AAPXSSerializationContext*)> sharedMemoryAllocatingRequester) {
-    return aapxs_dispatcher.setupInstances(this,
+bool aap::RemotePluginInstance::setupAAPXSInstances(std::function<bool(const char*, AAPXSSerializationContext*)> sharedMemoryAllocatingRequester) {
+    if (!aapxs_dispatcher.setupInstances(this,
                                            sharedMemoryAllocatingRequester,
                                            staticSendAAPXSRequest,
                                            staticSendAAPXSReply,
-                                           staticGetNewRequestId);
+                                           staticGetNewRequestId))
+        return false;
+    standards->initialize(&aapxs_dispatcher);
+    return true;
 }
 
 bool
@@ -278,5 +280,5 @@ aap::xs::AAPXSDefinitionClientRegistry *aap::RemotePluginInstance::getAAPXSRegis
 }
 
 void aap::RemotePluginInstance::setupAAPXS() {
-    standards = std::make_unique<xs::ClientStandardExtensions>(&aapxs_dispatcher);
+    standards = std::make_unique<xs::ClientStandardExtensions>();
 }

androidaudioplugin/src/main/cpp/core/hosting/PluginInstance.cpp

@@ -51,8 +51,6 @@ void aap::PluginInstance::completeInstantiation()
     assert(plugin);
 
     instantiation_state = PLUGIN_INSTANTIATION_STATE_UNPREPARED;
-
-    setupAAPXS();
 }
 
 void aap::PluginInstance::setupPortConfigDefaults() {