Add function to load Lora adapters at initialisation and runtime

examples/addon.node/addon.cpp

@@ -27,8 +27,17 @@ Napi::Number init(const Napi::CallbackInfo &info)
   g_params = new gpt_params;
   g_params->model = model;
   // load the model and apply lora adapter, if any
-  // TODO: Create a function that "swaps" the adapter
   // TODO: Create a function that holds more than one adapter in memory
+  if (obj.Has("lora")) {
+    Napi::String loraNapi = obj.Get("lora").As<Napi::String>();
+    std::string lora = loraNapi.Utf8Value();
+    if (!lora.empty()){
+      fprintf(stderr, "Loading lora from Path: %s\n", lora.c_str());
+      g_params->lora_adapter = lora;
+      g_params->use_mmap = false; // with mmap, ggml lora will throw segfault
+    }
+  }
+
   g_ctx = llama_init_from_gpt_params(*g_params);
   fprintf(stderr, "system_info: n_threads = %d / %d | %s\n", g_params->n_threads, std::thread::hardware_concurrency(), llama_print_system_info());
   if (g_ctx == NULL)
@@ -40,9 +49,25 @@ Napi::Number init(const Napi::CallbackInfo &info)
   return Napi::Number::New(env, 0);
 }
 
-
 std::mutex worker_mutex;
 
+// Function to load adapter at runtime
+Napi::Number swapLora(const Napi::CallbackInfo &info)
+{
+  Napi::Object obj = info[0].As<Napi::Object>();
+  Napi::String loraNapi = obj.Get("lora").As<Napi::String>();
+  std::string lora = loraNapi.Utf8Value();
+
+  fprintf(stderr, "Acquiring lock\n");
+  worker_mutex.lock();
+
+  fprintf(stderr, "Swapping lora from Path: %s\n", lora.c_str());
+  llama_apply_lora_from_file(g_ctx, lora.c_str(), NULL, get_num_physical_cores());
+
+  worker_mutex.unlock();
+  return Napi::Number::New(info.Env(), 0);  
+}
+
 class InferenceWorker {
 public:
   InferenceWorker(Napi::Env env, Napi::Function listener, std::string prompt)
@@ -260,6 +285,9 @@ Napi::Object Init(Napi::Env env, Napi::Object exports)
   exports.Set(
       Napi::String::New(env, "startAsync"),
       Napi::Function::New(env, StartAsync));
+  exports.Set(
+      Napi::String::New(env, "swapLora"),
+      Napi::Function::New(env, swapLora));
   return exports;
 }