text: /*
   *
   * Copyright 2015, Google Inc.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   *     * Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above
   * copyright notice, this list of conditions and the following disclaimer
   * in the documentation and/or other materials provided with the
   * distribution.
   *     * Neither the name of Google Inc. nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   */
  
  #include <vector>
  
  #include "grpc/support/log.h"
  
  #include <nan.h>
  #include <node.h>
  #include "call.h"
  #include "channel.h"
  #include "channel_credentials.h"
  #include "completion_queue.h"
  #include "completion_queue_async_worker.h"
  #include "grpc/grpc.h"
  #include "grpc/grpc_security.h"
  #include "timeval.h"
  
  namespace grpc {
  namespace node {
  
  using Nan::Callback;
  using Nan::EscapableHandleScope;
  using Nan::HandleScope;
  using Nan::Maybe;
  using Nan::MaybeLocal;
  using Nan::ObjectWrap;
  using Nan::Persistent;
  using Nan::Utf8String;
  
  using v8::Array;
  using v8::Exception;
  using v8::Function;
  using v8::FunctionTemplate;
  using v8::Integer;
  using v8::Local;
  using v8::Number;
  using v8::Object;
  using v8::String;
  using v8::Value;
  
  Callback *Channel::constructor;
  Persistent<FunctionTemplate> Channel::fun_tpl;
  
  bool ParseChannelArgs(Local<Value> args_val,
                        grpc_channel_args **channel_args_ptr) {
    if (args_val->IsUndefined() || args_val->IsNull()) {
      *channel_args_ptr = NULL;
      return true;
    }
    if (!args_val->IsObject()) {
      *channel_args_ptr = NULL;
      return false;
    }
    grpc_channel_args *channel_args =
        reinterpret_cast<grpc_channel_args *>(malloc(sizeof(grpc_channel_args)));
    *channel_args_ptr = channel_args;
    Local<Object> args_hash = Nan::To<Object>(args_val).ToLocalChecked();
    Local<Array> keys = Nan::GetOwnPropertyNames(args_hash).ToLocalChecked();
    channel_args->num_args = keys->Length();
    channel_args->args = reinterpret_cast<grpc_arg *>(
        calloc(channel_args->num_args, sizeof(grpc_arg)));
    for (unsigned int i = 0; i < channel_args->num_args; i++) {
      Local<Value> key = Nan::Get(keys, i).ToLocalChecked();
      Utf8String key_str(key);
      if (*key_str == NULL) {
        // Key string onversion failed
        return false;
      }
      Local<Value> value = Nan::Get(args_hash, key).ToLocalChecked();
      if (value->IsInt32()) {
        channel_args->args[i].type = GRPC_ARG_INTEGER;
        channel_args->args[i].value.integer = Nan::To<int32_t>(value).FromJust();
      } else if (value->IsString()) {
        Utf8String val_str(value);
        channel_args->args[i].type = GRPC_ARG_STRING;
        channel_args->args[i].value.string =
            reinterpret_cast<char *>(calloc(val_str.length() + 1, sizeof(char)));
        memcpy(channel_args->args[i].value.string, *val_str,
               val_str.length() + 1);
      } else {
        // The value does not match either of the accepted types
        return false;
      }
      channel_args->args[i].key =
          reinterpret_cast<char *>(calloc(key_str.length() + 1, sizeof(char)));
      memcpy(channel_args->args[i].key, *key_str, key_str.length() + 1);
    }
    return true;
  }
  
  void DeallocateChannelArgs(grpc_channel_args *channel_args) {
    if (channel_args == NULL) {
      return;
    }
    for (size_t i = 0; i < channel_args->num_args; i++) {
      if (channel_args->args[i].key == NULL) {
        /* NULL key implies that this argument and all subsequent arguments failed
         * to parse */
        break;
      }
      free(channel_args->args[i].key);
      if (channel_args->args[i].type == GRPC_ARG_STRING) {
        free(channel_args->args[i].value.string);
      }
    }
    free(channel_args->args);
    free(channel_args);
  }
  
  Channel::Channel(grpc_channel *channel) : wrapped_channel(channel) {}
  
  Channel::~Channel() {
    gpr_log(GPR_DEBUG, "Destroying channel");
    if (wrapped_channel != NULL) {
      grpc_channel_destroy(wrapped_channel);
    }
  }
  
  void Channel::Init(Local<Object> exports) {
    Nan::HandleScope scope;
    Local<FunctionTemplate> tpl = Nan::New<FunctionTemplate>(New);
    tpl->SetClassName(Nan::New("Channel").ToLocalChecked());
    tpl->InstanceTemplate()->SetInternalFieldCount(1);
    Nan::SetPrototypeMethod(tpl, "close", Close);
    Nan::SetPrototypeMethod(tpl, "getTarget", GetTarget);
    Nan::SetPrototypeMethod(tpl, "getConnectivityState", GetConnectivityState);
    Nan::SetPrototypeMethod(tpl, "watchConnectivityState",
                            WatchConnectivityState);
    fun_tpl.Reset(tpl);
    Local<Function> ctr = Nan::GetFunction(tpl).ToLocalChecked();
    Nan::Set(exports, Nan::New("Channel").ToLocalChecked(), ctr);
    constructor = new Callback(ctr);
  }
  
  bool Channel::HasInstance(Local<Value> val) {
    HandleScope scope;
    return Nan::New(fun_tpl)->HasInstance(val);
  }
  
  grpc_channel *Channel::GetWrappedChannel() { return this->wrapped_channel; }
  
  NAN_METHOD(Channel::New) {
    if (info.IsConstructCall()) {
      if (!info[0]->IsString()) {
        return Nan::ThrowTypeError(
            "Channel expects a string, a credential and an object");
      }
      grpc_channel *wrapped_channel;
      // Owned by the Channel object
      Utf8String host(info[0]);
      grpc_channel_credentials *creds;
      if (!ChannelCredentials::HasInstance(info[1])) {
        return Nan::ThrowTypeError(
            "Channel's second argument must be a ChannelCredentials");
      }
      ChannelCredentials *creds_object = ObjectWrap::Unwrap<ChannelCredentials>(
          Nan::To<Object>(info[1]).ToLocalChecked());
      creds = creds_object->GetWrappedCredentials();
      grpc_channel_args *channel_args_ptr = NULL;
      if (!ParseChannelArgs(info[2], &channel_args_ptr)) {
        DeallocateChannelArgs(channel_args_ptr);
        return Nan::ThrowTypeError(
            "Channel options must be an object with "
            "string keys and integer or string values");
      }
      if (creds == NULL) {
        wrapped_channel =
            grpc_insecure_channel_create(*host, channel_args_ptr, NULL);
      } else {
        wrapped_channel =
            grpc_secure_channel_create(creds, *host, channel_args_ptr, NULL);
      }
      DeallocateChannelArgs(channel_args_ptr);
      Channel *channel = new Channel(wrapped_channel);
      channel->Wrap(info.This());
      info.GetReturnValue().Set(info.This());
      return;
    } else {
      const int argc = 3;
      Local<Value> argv[argc] = {info[0], info[1], info[2]};
      MaybeLocal<Object> maybe_instance =
          Nan::NewInstance(constructor->GetFunction(), argc, argv);
      if (maybe_instance.IsEmpty()) {
        // There's probably a pending exception
        return;
      } else {
        info.GetReturnValue().Set(maybe_instance.ToLocalChecked());
      }
    }
  }
  
  NAN_METHOD(Channel::Close) {
    if (!HasInstance(info.This())) {
      return Nan::ThrowTypeError("close can only be called on Channel objects");
    }
    Channel *channel = ObjectWrap::Unwrap<Channel>(info.This());
    if (channel->wrapped_channel != NULL) {
      grpc_channel_destroy(channel->wrapped_channel);
      channel->wrapped_channel = NULL;
    }
  }
  
  NAN_METHOD(Channel::GetTarget) {
    if (!HasInstance(info.This())) {
      return Nan::ThrowTypeError(
          "getTarget can only be called on Channel objects");
    }
    Channel *channel = ObjectWrap::Unwrap<Channel>(info.This());
    info.GetReturnValue().Set(
        Nan::New(grpc_channel_get_target(channel->wrapped_channel))
            .ToLocalChecked());
  }
  
  NAN_METHOD(Channel::GetConnectivityState) {
    if (!HasInstance(info.This())) {
      return Nan::ThrowTypeError(
          "getConnectivityState can only be called on Channel objects");
    }
    Channel *channel = ObjectWrap::Unwrap<Channel>(info.This());
    int try_to_connect = (int)info[0]->Equals(Nan::True());
    info.GetReturnValue().Set(grpc_channel_check_connectivity_state(
        channel->wrapped_channel, try_to_connect));
  }
  
  NAN_METHOD(Channel::WatchConnectivityState) {
    if (!HasInstance(info.This())) {
      return Nan::ThrowTypeError(
          "watchConnectivityState can only be called on Channel objects");
    }
    if (!info[0]->IsUint32()) {
      return Nan::ThrowTypeError(
          "watchConnectivityState's first argument must be a channel state");
    }
    if (!(info[1]->IsNumber() || info[1]->IsDate())) {
      return Nan::ThrowTypeError(
          "watchConnectivityState's second argument must be a date or a number");
    }
    if (!info[2]->IsFunction()) {
      return Nan::ThrowTypeError(
          "watchConnectivityState's third argument must be a callback");
    }
    grpc_connectivity_state last_state = static_cast<grpc_connectivity_state>(
        Nan::To<uint32_t>(info[0]).FromJust());
    double deadline = Nan::To<double>(info[1]).FromJust();
    Local<Function> callback_func = info[2].As<Function>();
    Nan::Callback *callback = new Callback(callback_func);
    Channel *channel = ObjectWrap::Unwrap<Channel>(info.This());
    unique_ptr<OpVec> ops(new OpVec());
    grpc_channel_watch_connectivity_state(
        channel->wrapped_channel, last_state, MillisecondsToTimespec(deadline),
        GetCompletionQueue(),
        new struct tag(callback, ops.release(), NULL, Nan::Null()));
    CompletionQueueNext();
  }
  
  }  // namespace node
  }  // namespace grpc
  