// Copyright Joyent, Inc. and other Node contributors.

//

// Permission is hereby granted, free of charge, to any person obtaining a

// copy of this software and associated documentation files (the

// "Software"), to deal in the Software without restriction, including

// without limitation the rights to use, copy, modify, merge, publish,

// distribute, sublicense, and/or sell copies of the Software, and to permit

// persons to whom the Software is furnished to do so, subject to the

// following conditions:

//

// The above copyright notice and this permission notice shall be included

// in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

// USE OR OTHER DEALINGS IN THE SOFTWARE.

#include "async_wrap-inl.h"

#include "env-inl.h"

#include "handle_wrap.h"

#include "node_external_reference.h"

#include "node_process-inl.h"

#include "util-inl.h"

#include "v8.h"

namespace node {

using v8::Context;

using v8::FunctionCallbackInfo;

using v8::FunctionTemplate;

using v8::HandleScope;

using v8::Integer;

using v8::Isolate;

using v8::Local;

using v8::Object;

using v8::Value;

void DecreaseSignalHandlerCount(int signum);

namespace {

static Mutex handled_signals_mutex;

static std::map<int, int64_t> handled_signals;  // Signal -> number of handlers

class SignalWrap : public HandleWrap {

 public:

  static void Initialize(Local<Object> target,

                         Local<Value> unused,

                         Local<Context> context,

                         void* priv) {

    Environment* env = Environment::GetCurrent(context);

    Isolate* isolate = env->isolate();

    Local<FunctionTemplate> constructor = NewFunctionTemplate(isolate, New);

    constructor->InstanceTemplate()->SetInternalFieldCount(

        SignalWrap::kInternalFieldCount);

    constructor->Inherit(HandleWrap::GetConstructorTemplate(env));

    SetProtoMethod(isolate, constructor, "start", Start);

    SetProtoMethod(isolate, constructor, "stop", Stop);

    SetConstructorFunction(context, target, "Signal", constructor);

  }

  static void RegisterExternalReferences(ExternalReferenceRegistry* registry) {

    registry->Register(New);

    registry->Register(Start);

    registry->Register(Stop);

  }

  SET_NO_MEMORY_INFO()

  SET_MEMORY_INFO_NAME(SignalWrap)

  SET_SELF_SIZE(SignalWrap)

 private:

  static void New(const FunctionCallbackInfo<Value>& 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.

    CHECK(args.IsConstructCall());

    Environment* env = Environment::GetCurrent(args);

    new SignalWrap(env, args.This());

  }

  SignalWrap(Environment* env, Local<Object> object)

      : HandleWrap(env,

                   object,

                   reinterpret_cast<uv_handle_t*>(&handle_),

                   AsyncWrap::PROVIDER_SIGNALWRAP) {

    int r = uv_signal_init(env->event_loop(), &handle_);

    CHECK_EQ(r, 0);

  }

  void Close(v8::Local<v8::Value> close_callback) override {

    if (active_) {

      DecreaseSignalHandlerCount(handle_.signum);

      active_ = false;

    }

    HandleWrap::Close(close_callback);

  }

  static void Start(const FunctionCallbackInfo<Value>& args) {

    SignalWrap* wrap;

    ASSIGN_OR_RETURN_UNWRAP(&wrap, args.Holder());

    Environment* env = wrap->env();

    int signum;

    if (!args[0]->Int32Value(env->context()).To(&signum)) return;

#if defined(__POSIX__) && HAVE_INSPECTOR

    if (signum == SIGPROF) {

      Environment* env = Environment::GetCurrent(args);

      if (env->inspector_agent()->IsListening()) {

        ProcessEmitWarning(env,

                           "process.on(SIGPROF) is reserved while debugging");

        return;

      }

    }

#endif

    int err = uv_signal_start(

        &wrap->handle_,

        [](uv_signal_t* handle, int signum) {

          SignalWrap* wrap = ContainerOf(&SignalWrap::handle_, handle);

          Environment* env = wrap->env();

          HandleScope handle_scope(env->isolate());

          Context::Scope context_scope(env->context());

          Local<Value> arg = Integer::New(env->isolate(), signum);

          wrap->MakeCallback(env->onsignal_string(), 1, &arg);

        },

        signum);

    if (err == 0) {

      CHECK(!wrap->active_);

      wrap->active_ = true;

      Mutex::ScopedLock lock(handled_signals_mutex);

      handled_signals[signum]++;

    }

    args.GetReturnValue().Set(err);

  }

  static void Stop(const FunctionCallbackInfo<Value>& args) {

    SignalWrap* wrap;

    ASSIGN_OR_RETURN_UNWRAP(&wrap, args.Holder());

    if (wrap->active_)  {

      wrap->active_ = false;

      DecreaseSignalHandlerCount(wrap->handle_.signum);

    }

    int err = uv_signal_stop(&wrap->handle_);

    args.GetReturnValue().Set(err);

  }

  uv_signal_t handle_;

  bool active_ = false;

};

}  // anonymous namespace

void DecreaseSignalHandlerCount(int signum) {

  Mutex::ScopedLock lock(handled_signals_mutex);

  int64_t new_handler_count = --handled_signals[signum];

  CHECK_GE(new_handler_count, 0);

  if (new_handler_count == 0)

    handled_signals.erase(signum);

}

bool HasSignalJSHandler(int signum) {

  Mutex::ScopedLock lock(handled_signals_mutex);

  return handled_signals.find(signum) != handled_signals.end();

}

}  // namespace node

NODE_BINDING_CONTEXT_AWARE_INTERNAL(signal_wrap, node::SignalWrap::Initialize)

NODE_BINDING_EXTERNAL_REFERENCE(signal_wrap,

                                node::SignalWrap::RegisterExternalReferences)