pipe_wrap.cc

#include <node.h>
#include <node_buffer.h>
#include <req_wrap.h>
#include <stream_wrap.h>

// Rules:
//
// - Do not throw from handle methods. Set errno.
//
// - MakeCallback may only be made directly off the event loop.
//   That is there can be no JavaScript stack frames underneith it.
//   (Is there anyway to assert that?)
//
// - No use of v8::WeakReferenceCallback. The close callback signifies that
//   we're done with a handle - external resources can be freed.
//
// - Reusable?
//
// - The uv_close_cb is used to free the c++ object. The close callback
//   is not made into javascript land.
//
// - uv_ref, uv_unref counts are managed at this layer to avoid needless
//   js/c++ boundary crossing. At the javascript layer that should all be
//   taken care of.


#define UNWRAP \
  assert(!args.Holder().IsEmpty()); \
  assert(args.Holder()->InternalFieldCount() > 0); \
  PipeWrap* wrap =  \
      static_cast<PipeWrap*>(args.Holder()->GetPointerFromInternalField(0)); \
  if (!wrap) { \
    SetErrno(UV_EBADF); \
    return scope.Close(Integer::New(-1)); \
  }

namespace node {

using v8::Object;
using v8::Handle;
using v8::Local;
using v8::Persistent;
using v8::Value;
using v8::HandleScope;
using v8::FunctionTemplate;
using v8::String;
using v8::Function;
using v8::TryCatch;
using v8::Context;
using v8::Arguments;
using v8::Integer;

static Persistent<Function> constructor;


// TODO share with TCPWrap?
typedef class ReqWrap<uv_connect_t> ConnectWrap;


class PipeWrap : StreamWrap {
 public:

  static void Initialize(Handle<Object> target) {
    StreamWrap::Initialize(target);

    HandleScope scope;

    Local<FunctionTemplate> t = FunctionTemplate::New(New);
    t->SetClassName(String::NewSymbol("Pipe"));

    t->InstanceTemplate()->SetInternalFieldCount(1);

    NODE_SET_PROTOTYPE_METHOD(t, "readStart", StreamWrap::ReadStart);
    NODE_SET_PROTOTYPE_METHOD(t, "readStop", StreamWrap::ReadStop);
    NODE_SET_PROTOTYPE_METHOD(t, "write", StreamWrap::Write);
    NODE_SET_PROTOTYPE_METHOD(t, "shutdown", StreamWrap::Shutdown);
    NODE_SET_PROTOTYPE_METHOD(t, "close", StreamWrap::Close);

    NODE_SET_PROTOTYPE_METHOD(t, "bind", Bind);
    NODE_SET_PROTOTYPE_METHOD(t, "listen", Listen);
    NODE_SET_PROTOTYPE_METHOD(t, "connect", Connect);

    constructor = Persistent<Function>::New(t->GetFunction());

    target->Set(String::NewSymbol("Pipe"), constructor);
  }

 private:
  static Handle<Value> New(const Arguments& args) {
    // This constructor should not be exposed to public javascript.
    // Therefore we assert that we are not trying to call this as a
    // normal function.
    assert(args.IsConstructCall());

    HandleScope scope;
    PipeWrap* wrap = new PipeWrap(args.This());
    assert(wrap);

    return scope.Close(args.This());
  }

  PipeWrap(Handle<Object> object) : StreamWrap(object,
                                              (uv_stream_t*) &handle_) {
    int r = uv_pipe_init(&handle_);
    assert(r == 0); // How do we proxy this error up to javascript?
                    // Suggestion: uv_pipe_init() returns void.
  }

  static Handle<Value> Bind(const Arguments& args) {
    HandleScope scope;

    UNWRAP

    String::AsciiValue name(args[0]->ToString());

    int r = uv_pipe_bind(&wrap->handle_, *name);

    // Error starting the pipe.
    if (r) SetErrno(uv_last_error().code);

    return scope.Close(Integer::New(r));
  }

  static Handle<Value> Listen(const Arguments& args) {
    HandleScope scope;

    UNWRAP

    int backlog = args[0]->Int32Value();

    int r = uv_pipe_listen(&wrap->handle_, OnConnection);

    // Error starting the pipe.
    if (r) SetErrno(uv_last_error().code);

    return scope.Close(Integer::New(r));
  }

  // TODO maybe share with TCPWrap?
  static void OnConnection(uv_handle_t* handle, int status) {
    HandleScope scope;

    PipeWrap* wrap = static_cast<PipeWrap*>(handle->data);
    assert(&wrap->handle_ == (uv_pipe_t*)handle);

    // We should not be getting this callback if someone as already called
    // uv_close() on the handle.
    assert(wrap->object_.IsEmpty() == false);

    if (status != 0) {
      // TODO Handle server error (set errno and call onconnection with NULL)
      assert(0);
      return;
    }

    // Instanciate the client javascript object and handle.
    Local<Object> client_obj = constructor->NewInstance();

    // Unwrap the client javascript object.
    assert(client_obj->InternalFieldCount() > 0);
    PipeWrap* client_wrap =
        static_cast<PipeWrap*>(client_obj->GetPointerFromInternalField(0));

    int r = uv_accept(handle, (uv_stream_t*)&client_wrap->handle_);

    // uv_accept should always work.
    assert(r == 0);

    // Successful accept. Call the onconnection callback in JavaScript land.
    Local<Value> argv[1] = { client_obj };
    MakeCallback(wrap->object_, "onconnection", 1, argv);
  }

  // TODO Maybe share this with TCPWrap?
  static void AfterConnect(uv_connect_t* req, int status) {
    ConnectWrap* req_wrap = (ConnectWrap*) req->data;
    PipeWrap* wrap = (PipeWrap*) req->handle->data;

    HandleScope scope;

    // The wrap and request objects should still be there.
    assert(req_wrap->object_.IsEmpty() == false);
    assert(wrap->object_.IsEmpty() == false);

    if (status) {
      SetErrno(uv_last_error().code);
    }

    Local<Value> argv[3] = {
      Integer::New(status),
      Local<Value>::New(wrap->object_),
      Local<Value>::New(req_wrap->object_)
    };

    MakeCallback(req_wrap->object_, "oncomplete", 3, argv);

    delete req_wrap;
  }

  static Handle<Value> Connect(const Arguments& args) {
    HandleScope scope;

    UNWRAP

    String::AsciiValue name(args[0]->ToString());

    ConnectWrap* req_wrap = new ConnectWrap();

    int r = uv_pipe_connect(&req_wrap->req_,
                            &wrap->handle_,
                            *name,
                            AfterConnect);

    req_wrap->Dispatched();

    if (r) {
      SetErrno(uv_last_error().code);
      delete req_wrap;
      return scope.Close(v8::Null());
    } else {
      return scope.Close(req_wrap->object_);
    }
  }

  uv_pipe_t handle_;
};


}  // namespace node

NODE_MODULE(node_pipe_wrap, node::PipeWrap::Initialize);