Add Native Directive Example

Examples/javascript/native/example.i

@@ -0,0 +1,92 @@
+/* File : example.i */
+%module example
+
+
+%wrapper
+%{
+#include <cstring>
+#include <string>
+
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x031903)
+#    define V8_RETURN(val) return scope.Close(val)
+#else
+#    define V8_RETURN(val) args.GetReturnValue().Set(val); return
+#endif
+#if (V8_MAJOR_VERSION-0) < 4 && (SWIG_V8_VERSION < 0x032318)
+#    define V8_UNDEFINED() v8::Undefined()
+#else
+#    define V8_UNDEFINED() v8::Undefined(v8::Isolate::GetCurrent())
+#endif
+
+
+// 'unused' attribute only necessary for GNUC < v3.4
+static /* __attribute__ ((__unused__)) */ V8ErrorHandler V8_ErrorHandler;
+
+
+typedef struct worker_packet {
+    // -- basic --
+	uv_work_t request;
+	v8::Persistent<v8::Function> callback;
+	// -- persistent variables --
+	std::string result;
+	// -- async operation --
+	void (*execute)(std::string&);
+} worker_packet;
+
+
+// async process - parallel with node thread
+static void work_async(uv_work_t* request) {
+    worker_packet* packet = static_cast<worker_packet*>(request->data);
+    packet->execute(packet->result);
+    // add a delay for dramatic effect - not necessary
+}
+
+
+// send async result back to node's thread
+static void work_complete(uv_work_t* request, int status) {
+    v8::Isolate* iso = v8::Isolate::GetCurrent();
+    v8::HandleScope scope(iso);
+    worker_packet* packet = static_cast<worker_packet*>(request->data);
+    const int argc = 1;
+    v8::Handle<v8::Value> argv[] = {
+        v8::String::NewFromUtf8(iso, packet->result.c_str())
+    };
+    v8::Local<v8::Function>::New(iso, packet->callback)->Call
+        (iso->GetCurrentContext()->Global(), argc, argv);
+    packet->callback.Reset();
+    delete work;
+}
+
+
+static void entry(const v8::FunctionCallbackInfo<v8::Value>& args) {
+    v8::Isolate* iso = v8::Isolate::GetCurrent();
+    v8::Local<v8::Value> value = args[0];
+    if (!value->IsFunction()) {
+        V8_ErrorHandler.error((-1), "Invalid parameter type.");
+        return;
+    }
+    worker_packet* packet = new worker_packet();
+    packet->request.data = packet;
+    packet->execute = [](std::string& res) { res = "My delayed message."; };
+    v8::Local<v8::Function> callback = v8::Local<v8::Function>::Cast(value);
+    packet->callback.Reset(iso, callback);
+    uv_queue_work(uv_default_loop(), &packet->request,
+        work_async, work_complete);
+    args.GetReturnValue().Set(Undefined(iso));
+}
+
+
+void JavaScript_exampleV8_callback_function(const v8::Arguments& args) {
+    v8::HandleScope scope
+	if (args.Length() != 1) {
+        V8_ErrorHandler.error((-1), "Illegal number of arguments.");
+        V8_RETURN(V8_UNDEFINED());
+	}
+    entry(args);
+    v8::Handle<v8::Value> jsresult = V8_UNDEFINED();
+    V8_RETURN(jsresult);
+}
+%}
+
+
+%native(num_to_string) void JavaScript_exampleV8_callback_function();