v8pp

Binding example

v8::Isolate* isolate;
int var;
int get_var() { return var + 1; }
void set_var(int x) { var = x + 1; }
struct X
{
	X(int v, bool u) : var(v) {}
	int var;
	int get() const { return var; }
	voi set(int x) { var = x; } 
};
// bind free variables and functions
v8pp::module mylib(isolate);
mylib
 // set read-only attribute
 .set_const("PI", 3.1415)
	// set variable available in JavaScript with name `var`
	.set("var", var)
	// set function get_var as `fun`
	.set("fun", &get_var)
	// set property `prop` with getter get_var() and setter set_var()
 .set("prop", property(get_var, set_var));
// bind class
v8pp::class_<X> X_class(isolate);
X_class
	// specify X constructor signature
	.ctor<int, bool>()
	// bind variable
	.set("var", &X::var)
	// bind function
	.set("fun", &X::set)
	// bind read-only property
	.set("prop", property(&X::get));
// set class into the module template
mylib.set("X", X_class);
// set bindings in global object as `mylib`
isolate->GetCurrentContext()->Global()->Set(
	v8::String::NewFromUtf8(isolate, "mylib"), mylib.new_instance());

mylib.var = mylib.PI + mylib.fun();
var x = new mylib.X(1, true);
mylib.prop = x.prop + x.fun();

Node.js and io.js addons

void RegisterModule(v8::Handle<v8::Object> exports)
{
	v8pp::module addon(v8::Isolate::GetCurrent());
	// set bindings... 
	addon
		.set("fun", &function)
		.set("cls", my_class)
		;
	// set bindings as exports object prototype
	exports->SetPrototype(addon.new_instance());
}

v8pp also provides

v8pp module example

#include <iostream>
#include <v8pp/module.hpp>
namespace console {
void log(v8::FunctionCallbackInfo<v8::Value> const& args)
{
	v8::HandleScope handle_scope(args.GetIsolate());
	for (int i = 0; i < args.Length(); ++i)
	{
		if (i > 0) std::cout << ' ';
		v8::String::Utf8Value str(args[i]);
		std::cout << *str;
	}
	std::cout << std::endl;
}
v8::Handle<v8::Value> init(v8::Isolate* isolate)
{
	v8pp::module m(isolate);
	m.set("log", &log);
	return m.new_instance();
}
} // namespace console

Turning a v8pp module into a v8pp plugin

V8PP_PLUGIN_INIT(v8::Isolate* isolate)
{
	return console::init(isolate);
}

v8pp class binding example

#include <v8pp/module.hpp>
#include <v8pp/class.hpp>
#include <fstream>
namespace file {
bool rename(char const* src, char const* dest)
{
	return std::rename(src, dest) == 0;
}
class file_base
{
public:
	bool is_open() const { return stream_.is_open(); }
	bool good() const { return stream_.good(); }
	bool eof() const { return stream_.eof(); }
	void close() { stream_.close(); }
protected:
	std::fstream stream_;
};
class file_writer : public file_base
{
public:
	explicit file_writer(v8::FunctionCallbackInfo<v8::Value> const& args)
	{
		if (args.Length() == 1)
		{
			v8::String::Utf8Value str(args[0]);
			open(*str);
		}
	}
	bool open(char const* path)
	{
		stream_.open(path, std::ios_base::out);
		return stream_.good();
	}
	void print(v8::FunctionCallbackInfo<v8::Value> const& args)
	{
		v8::HandleScope scope(args.GetIsolate());
		for (int i = 0; i < args.Length(); ++i)
		{
			if (i > 0) stream_ << ' ';
			v8::String::Utf8Value str(args[i]);
			stream_ << *str;
		}
	}
	void println(v8::FunctionCallbackInfo<v8::Value> const& args)
	{
		print(args);
		stream_ << std::endl;
	}
};
class file_reader : public file_base
{
public:
	explicit file_reader(char const* path)
	{
		open(path);
	}
	bool open(const char* path)
	{
		stream_.open(path, std::ios_base::in);
		return stream_.good();
	}
	v8::Handle<v8::Value> getline(v8::Isolate* isolate)
	{
		if ( stream_.good() && ! stream_.eof())
		{
			std::string line;
			std::getline(stream_, line);
			return v8pp::to_v8(isolate, line);
		}
		else
		{
			return v8::Undefined(isolate);
		}
	}
};
v8::Handle<v8::Value> init(v8::Isolate* isolate)
{
	v8::EscapableHandleScope scope(isolate);
	// file_base binding, no .ctor() specified, object creation disallowed in JavaScript
	v8pp::class_<file_base> file_base_class(isolate);
	file_base_class
		.set("close", &file_base::close)
		.set("good", &file_base::good)
		.set("is_open", &file_base::is_open)
		.set("eof", &file_base::eof)
		;
	// .ctor<> template arguments declares types of file_writer constructor
	// file_writer inherits from file_base_class
	v8pp::class_<file_writer> file_writer_class(isolate);
	file_writer_class
		.ctor<v8::FunctionCallbackInfo<v8::Value> const&>()
		.inherit<file_base>()
		.set("open", &file_writer::open)
		.set("print", &file_writer::print)
		.set("println", &file_writer::println)
		;
	// .ctor<> template arguments declares types of file_reader constructor.
	// file_base inherits from file_base_class
	v8pp::class_<file_reader> file_reader_class(isolate);
	file_reader_class
		.ctor<char const*>()
		.inherit<file_base>()
		.set("open", &file_reader::open)
		.set("getln", &file_reader::getline)
		;
	// Create a module to add classes and functions to and return a
	// new instance of the module to be embedded into the v8 context
	v8pp::module m(isolate);
	m.set("rename", &rename)
	 .set("writer", file_writer_class)
	 .set("reader", file_reader_class)
		;
	return scope.Escape(m.new_instance());
}
} // namespace file
V8PP_PLUGIN_INIT(v8::Isolate* isolate)
{
	return file::init(isolate);
}

Creating a v8 context capable of using require() function

#include <v8pp/context.hpp>
v8pp::context context;
context.set_lib_path("path/to/plugins/lib");
// script can now use require() function. An application
// that uses v8pp::context must link against v8pp library.
v8::HandleScope scope(context.isolate());
context.run_file("some_file.js");

Using require() from JavaScript

// Load the file module from the class binding example and the
// console module.
var file = require('file'),
 console = require('console')
var writer = new file.writer("file")
if (writer.is_open()) {
 writer.println("some text")
 writer.close()
 if (! file.rename("file", "newfile"))
 console.log("could not rename file")
}
else console.log("could not open `file'")
console.log("exit")

Create a handle to an externally referenced C++ class.

// Memory for C++ class will remain when JavaScript object is deleted.
// v8pp::no_factory avoids creating any constructor for your C++ class from
// JavaScript, useful for classes you only wish to inject.
typedef v8pp::class_<my_class> my_class_wrapper(isolate);
v8::Handle<v8::Value> val = my_class_wrapper::reference_external(&my_class::instance());
// Assuming my_class::instance() returns reference to class

Import externally created C++ class into v8pp.

// Memory for c++ object will be reclaimed by JavaScript using "delete" when
// JavaScript class is deleted.
typedef v8pp::class_<my_class> my_class_wrapper(isolate);
v8::Handle<v8::Value> val = my_class_wrapper::import_external(new my_class);

Compile-time configuration

v8pp alternatives