text: #include <string.h>
  #include "node.h"
  #include "node_buffer.h"
  #include "node_version.h"
  
  #include "macros.h"
  #include "database.h"
  #include "statement.h"
  #include "env.h"
  #include "env-inl.h"
  
  using namespace node_sqlite3;
  
  NAN_MODULE_INIT(Statement::Init) {
      Nan::HandleScope scope;
  
      Local<FunctionTemplate> t = Nan::New<FunctionTemplate>(New);
  
      t->InstanceTemplate()->SetInternalFieldCount(1);
      t->SetClassName(Nan::New("Statement").ToLocalChecked());
  
      Nan::SetPrototypeMethod(t, "bind", Bind);
      Nan::SetPrototypeMethod(t, "get", Get);
      Nan::SetPrototypeMethod(t, "run", Run);
      Nan::SetPrototypeMethod(t, "all", All);
      Nan::SetPrototypeMethod(t, "each", Each);
      Nan::SetPrototypeMethod(t, "reset", Reset);
      Nan::SetPrototypeMethod(t, "finalize", Finalize);
  
      Nan::Set(target, Nan::New("Statement").ToLocalChecked(),
          Nan::GetFunction(t).ToLocalChecked());
  }
  
  void Statement::Process() {
      if (finalized && !queue.empty()) {
          return CleanQueue();
      }
  
      while (prepared && !locked && !queue.empty()) {
          Call* call = queue.front();
          queue.pop();
  
          call->callback(call->baton);
          delete call;
      }
  }
  
  void Statement::Schedule(Work_Callback callback, Baton* baton) {
      if (finalized) {
          queue.push(new Call(callback, baton));
          CleanQueue();
      }
      else if (!prepared || locked) {
          queue.push(new Call(callback, baton));
      }
      else {
          callback(baton);
      }
  }
  
  template <class T> void Statement::Error(T* baton) {
      Nan::HandleScope scope;
  
      Statement* stmt = baton->stmt;
      // Fail hard on logic errors.
      assert(stmt->status != 0);
      EXCEPTION(Nan::New(stmt->message.c_str()).ToLocalChecked(), stmt->status, exception);
  
      Local<Function> cb = Nan::New(baton->callback);
  
      if (!cb.IsEmpty() && cb->IsFunction()) {
          Local<Value> argv[] = { exception };
          TRY_CATCH_CALL(stmt->handle(), cb, 1, argv);
      }
      else {
          Local<Value> argv[] = { Nan::New("error").ToLocalChecked(), exception };
          EMIT_EVENT(stmt->handle(), 2, argv);
      }
  }
  
  // { Database db, String sql, Array params, Function callback }
  NAN_METHOD(Statement::New) {
      if (!info.IsConstructCall()) {
          return Nan::ThrowTypeError("Use the new operator to create new Statement objects");
      }
  
      int length = info.Length();
  
      if (length <= 0 || !Database::HasInstance(info[0])) {
          return Nan::ThrowTypeError("Database object expected");
      }
      else if (length <= 1 || !info[1]->IsString()) {
          return Nan::ThrowTypeError("SQL query expected");
      }
      else if (length > 2 && !info[2]->IsUndefined() && !info[2]->IsFunction()) {
          return Nan::ThrowTypeError("Callback expected");
      }
  
      Database* db = Nan::ObjectWrap::Unwrap<Database>(info[0].As<Object>());
      Local<String> sql = Local<String>::Cast(info[1]);
  
      /*
      info.This()->ForceSet(Nan::New("sql").ToLocalChecked(), sql, ReadOnly);
      */
      CHECK(info.This()->DefineOwnProperty(info.GetIsolate()->GetCurrentContext(),
          Nan::New("sql").ToLocalChecked(), sql, ReadOnly).ToChecked());
  
      Statement* stmt = new Statement(db);
      stmt->Wrap(info.This());
  
      Environment* env = Environment::GetCurrent(info.GetIsolate());
  
      PrepareBaton* baton = new PrepareBaton(db, Local<Function>::Cast(info[2]), stmt, env->event_loop());
      baton->sql = std::string(*Nan::Utf8String(sql));
      db->Schedule(Work_BeginPrepare, baton);
  
      info.GetReturnValue().Set(info.This());
  }
  
  void Statement::Work_BeginPrepare(Database::Baton* baton) {
      assert(baton->db->open);
      baton->db->pending++;
      int status = uv_queue_work(baton->loop,
          &baton->request, Work_Prepare, (uv_after_work_cb)Work_AfterPrepare);
      assert(status == 0);
  }
  
  void Statement::Work_Prepare(uv_work_t* req) {
      STATEMENT_INIT(PrepareBaton);
  
      // In case preparing fails, we use a mutex to make sure we get the associated
      // error message.
      sqlite3_mutex* mtx = sqlite3_db_mutex(baton->db->_handle);
      sqlite3_mutex_enter(mtx);
  
      stmt->status = sqlite3_prepare_v2(
          baton->db->_handle,
          baton->sql.c_str(),
          baton->sql.size(),
          &stmt->_handle,
          NULL
      );
  
      if (stmt->status != SQLITE_OK) {
          stmt->message = std::string(sqlite3_errmsg(baton->db->_handle));
          stmt->_handle = NULL;
      }
  
      sqlite3_mutex_leave(mtx);
  }
  
  void Statement::Work_AfterPrepare(uv_work_t* req) {
      Nan::HandleScope scope;
  
      STATEMENT_INIT(PrepareBaton);
  
      if (stmt->status != SQLITE_OK) {
          Error(baton);
          stmt->Finalize();
      }
      else {
          stmt->prepared = true;
          Local<Function> cb = Nan::New(baton->callback);
          if (!cb.IsEmpty() && cb->IsFunction()) {
              Local<Value> argv[] = { Nan::Null() };
              TRY_CATCH_CALL(stmt->handle(), cb, 1, argv);
          }
      }
  
      STATEMENT_END();
  }
  
  template <class T> Values::Field*
                     Statement::BindParameter(const Local<Value> source, T pos) {
      if (source->IsString() || source->IsRegExp()) {
          Nan::Utf8String val(source);
          return new Values::Text(pos, val.length(), *val);
      }
      else if (source->IsInt32()) {
          return new Values::Integer(pos, Nan::To<int32_t>(source).FromJust());
      }
      else if (source->IsNumber()) {
          return new Values::Float(pos, Nan::To<double>(source).FromJust());
      }
      else if (source->IsBoolean()) {
          return new Values::Integer(pos, Nan::To<bool>(source).FromJust() ? 1 : 0);
      }
      else if (source->IsNull()) {
          return new Values::Null(pos);
      }
      else if (Buffer::HasInstance(source)) {
          Local<Object> buffer = Nan::To<Object>(source).ToLocalChecked();
          return new Values::Blob(pos, Buffer::Length(buffer), Buffer::Data(buffer));
      }
      else if (source->IsDate()) {
          return new Values::Float(pos, Nan::To<double>(source).FromJust());
      }
      else {
          return NULL;
      }
  }
  
  template <class T> T* Statement::Bind(Nan::NAN_METHOD_ARGS_TYPE info, int start, int last) {
      Nan::HandleScope scope;
  
      if (last < 0) last = info.Length();
      Local<Function> callback;
      if (last > start && info[last - 1]->IsFunction()) {
          callback = Local<Function>::Cast(info[last - 1]);
          last--;
      }
  
      Environment* env = Environment::GetCurrent(info.GetIsolate());
  
      T* baton = new T(this, callback, env->event_loop());
  
      if (start < last) {
          if (info[start]->IsArray()) {
              Local<Array> array = Local<Array>::Cast(info[start]);
              int length = array->Length();
              // Note: bind parameters start with 1.
              for (int i = 0, pos = 1; i < length; i++, pos++) {
                  baton->parameters.push_back(BindParameter(Nan::Get(array, i).ToLocalChecked(), pos));
              }
          }
          else if (!info[start]->IsObject() || info[start]->IsRegExp() || info[start]->IsDate() || Buffer::HasInstance(info[start])) {
              // Parameters directly in array.
              // Note: bind parameters start with 1.
              for (int i = start, pos = 1; i < last; i++, pos++) {
                  baton->parameters.push_back(BindParameter(info[i], pos));
              }
          }
          else if (info[start]->IsObject()) {
              Local<Object> object = Local<Object>::Cast(info[start]);
              Local<Array> array = Nan::GetPropertyNames(object).ToLocalChecked();
              int length = array->Length();
              for (int i = 0; i < length; i++) {
                  Local<Value> name = Nan::Get(array, i).ToLocalChecked();
  
                  if (name->IsInt32()) {
                      baton->parameters.push_back(
                          BindParameter(Nan::Get(object, name).ToLocalChecked(), Nan::To<int32_t>(name).FromJust()));
                  }
                  else {
                      baton->parameters.push_back(BindParameter(Nan::Get(object, name).ToLocalChecked(),
                          *Nan::Utf8String(name)));
                  }
              }
          }
          else {
              return NULL;
          }
      }
  
      return baton;
  }
  
  bool Statement::Bind(const Parameters & parameters) {
      if (parameters.size() == 0) {
          return true;
      }
  
      sqlite3_reset(_handle);
      sqlite3_clear_bindings(_handle);
  
      Parameters::const_iterator it = parameters.begin();
      Parameters::const_iterator end = parameters.end();
  
      for (; it < end; ++it) {
          Values::Field* field = *it;
  
          if (field != NULL) {
              int pos;
              if (field->index > 0) {
                  pos = field->index;
              }
              else {
                  pos = sqlite3_bind_parameter_index(_handle, field->name.c_str());
              }
  
              switch (field->type) {
                  case SQLITE_INTEGER: {
                      status = sqlite3_bind_int(_handle, pos,
                          ((Values::Integer*)field)->value);
                  } break;
                  case SQLITE_FLOAT: {
                      status = sqlite3_bind_double(_handle, pos,
                          ((Values::Float*)field)->value);
                  } break;
                  case SQLITE_TEXT: {
                      status = sqlite3_bind_text(_handle, pos,
                          ((Values::Text*)field)->value.c_str(),
                          ((Values::Text*)field)->value.size(), SQLITE_TRANSIENT);
                  } break;
                  case SQLITE_BLOB: {
                      status = sqlite3_bind_blob(_handle, pos,
                          ((Values::Blob*)field)->value,
                          ((Values::Blob*)field)->length, SQLITE_TRANSIENT);
                  } break;
                  case SQLITE_NULL: {
                      status = sqlite3_bind_null(_handle, pos);
                  } break;
              }
  
              if (status != SQLITE_OK) {
                  message = std::string(sqlite3_errmsg(db->_handle));
                  return false;
              }
          }
      }
  
      return true;
  }
  
  NAN_METHOD(Statement::Bind) {
      Statement* stmt = Nan::ObjectWrap::Unwrap<Statement>(info.This());
  
      Baton* baton = stmt->Bind<Baton>(info);
      if (baton == NULL) {
          return Nan::ThrowTypeError("Data type is not supported");
      }
      else {
          stmt->Schedule(Work_BeginBind, baton);
          info.GetReturnValue().Set(info.This());
      }
  }
  
  void Statement::Work_BeginBind(Baton* baton) {
      STATEMENT_BEGIN(Bind);
  }
  
  void Statement::Work_Bind(uv_work_t* req) {
      STATEMENT_INIT(Baton);
  
      sqlite3_mutex* mtx = sqlite3_db_mutex(stmt->db->_handle);
      sqlite3_mutex_enter(mtx);
      stmt->Bind(baton->parameters);
      sqlite3_mutex_leave(mtx);
  }
  
  void Statement::Work_AfterBind(uv_work_t* req) {
      Nan::HandleScope scope;
  
      STATEMENT_INIT(Baton);
  
      if (stmt->status != SQLITE_OK) {
          Error(baton);
      }
      else {
          // Fire callbacks.
          Local<Function> cb = Nan::New(baton->callback);
          if (!cb.IsEmpty() && cb->IsFunction()) {
              Local<Value> argv[] = { Nan::Null() };
              TRY_CATCH_CALL(stmt->handle(), cb, 1, argv);
          }
      }
  
      STATEMENT_END();
  }
  
  
  
  NAN_METHOD(Statement::Get) {
      Statement* stmt = Nan::ObjectWrap::Unwrap<Statement>(info.This());
  
      Baton* baton = stmt->Bind<RowBaton>(info);
      if (baton == NULL) {
          return Nan::ThrowError("Data type is not supported");
      }
      else {
          stmt->Schedule(Work_BeginGet, baton);
          info.GetReturnValue().Set(info.This());
      }
  }
  
  void Statement::Work_BeginGet(Baton* baton) {
      STATEMENT_BEGIN(Get);
  }
  
  void Statement::Work_Get(uv_work_t* req) {
      STATEMENT_INIT(RowBaton);
  
      if (stmt->status != SQLITE_DONE || baton->parameters.size()) {
          sqlite3_mutex* mtx = sqlite3_db_mutex(stmt->db->_handle);
          sqlite3_mutex_enter(mtx);
  
          if (stmt->Bind(baton->parameters)) {
              stmt->status = sqlite3_step(stmt->_handle);
  
              if (!(stmt->status == SQLITE_ROW || stmt->status == SQLITE_DONE)) {
                  stmt->message = std::string(sqlite3_errmsg(stmt->db->_handle));
              }
          }
  
          sqlite3_mutex_leave(mtx);
  
          if (stmt->status == SQLITE_ROW) {
              // Acquire one result row before returning.
              GetRow(&baton->row, stmt->_handle);
          }
      }
  }
  
  void Statement::Work_AfterGet(uv_work_t* req) {
      Nan::HandleScope scope;
  
      STATEMENT_INIT(RowBaton);
  
      if (stmt->status != SQLITE_ROW && stmt->status != SQLITE_DONE) {
          Error(baton);
      }
      else {
          // Fire callbacks.
          Local<Function> cb = Nan::New(baton->callback);
          if (!cb.IsEmpty() && cb->IsFunction()) {
              if (stmt->status == SQLITE_ROW) {
                  // Create the result array from the data we acquired.
                  Local<Value> argv[] = { Nan::Null(), RowToJS(&baton->row) };
                  TRY_CATCH_CALL(stmt->handle(), cb, 2, argv);
              }
              else {
                  Local<Value> argv[] = { Nan::Null() };
                  TRY_CATCH_CALL(stmt->handle(), cb, 1, argv);
              }
          }
      }
  
      STATEMENT_END();
  }
  
  NAN_METHOD(Statement::Run) {
      Statement* stmt = Nan::ObjectWrap::Unwrap<Statement>(info.This());
  
      Baton* baton = stmt->Bind<RunBaton>(info);
      if (baton == NULL) {
          return Nan::ThrowError("Data type is not supported");
      }
      else {
          stmt->Schedule(Work_BeginRun, baton);
          info.GetReturnValue().Set(info.This());
      }
  }
  
  void Statement::Work_BeginRun(Baton* baton) {
      STATEMENT_BEGIN(Run);
  }
  
  void Statement::Work_Run(uv_work_t* req) {
      STATEMENT_INIT(RunBaton);
  
      sqlite3_mutex* mtx = sqlite3_db_mutex(stmt->db->_handle);
      sqlite3_mutex_enter(mtx);
  
      // Make sure that we also reset when there are no parameters.
      if (!baton->parameters.size()) {
          sqlite3_reset(stmt->_handle);
      }
  
      if (stmt->Bind(baton->parameters)) {
          stmt->status = sqlite3_step(stmt->_handle);
  
          if (!(stmt->status == SQLITE_ROW || stmt->status == SQLITE_DONE)) {
              stmt->message = std::string(sqlite3_errmsg(stmt->db->_handle));
          }
          else {
              baton->inserted_id = sqlite3_last_insert_rowid(stmt->db->_handle);
              baton->changes = sqlite3_changes(stmt->db->_handle);
          }
      }
  
      sqlite3_mutex_leave(mtx);
  }
  
  void Statement::Work_AfterRun(uv_work_t* req) {
      Nan::HandleScope scope;
  
      STATEMENT_INIT(RunBaton);
  
      if (stmt->status != SQLITE_ROW && stmt->status != SQLITE_DONE) {
          Error(baton);
      }
      else {
          // Fire callbacks.
          Local<Function> cb = Nan::New(baton->callback);
          if (!cb.IsEmpty() && cb->IsFunction()) {
              Nan::Set(stmt->handle(), Nan::New("lastID").ToLocalChecked(), Nan::New<Number>(baton->inserted_id));
              Nan::Set(stmt->handle(), Nan::New("changes").ToLocalChecked(), Nan::New(baton->changes));
  
              Local<Value> argv[] = { Nan::Null() };
              TRY_CATCH_CALL(stmt->handle(), cb, 1, argv);
          }
      }
  
      STATEMENT_END();
  }
  
  NAN_METHOD(Statement::All) {
      Statement* stmt = Nan::ObjectWrap::Unwrap<Statement>(info.This());
  
      Baton* baton = stmt->Bind<RowsBaton>(info);
      if (baton == NULL) {
          return Nan::ThrowError("Data type is not supported");
      }
      else {
          stmt->Schedule(Work_BeginAll, baton);
          info.GetReturnValue().Set(info.This());
      }
  }
  
  void Statement::Work_BeginAll(Baton* baton) {
      STATEMENT_BEGIN(All);
  }
  
  void Statement::Work_All(uv_work_t* req) {
      STATEMENT_INIT(RowsBaton);
  
      sqlite3_mutex* mtx = sqlite3_db_mutex(stmt->db->_handle);
      sqlite3_mutex_enter(mtx);
  
      // Make sure that we also reset when there are no parameters.
      if (!baton->parameters.size()) {
          sqlite3_reset(stmt->_handle);
      }
  
      if (stmt->Bind(baton->parameters)) {
          while ((stmt->status = sqlite3_step(stmt->_handle)) == SQLITE_ROW) {
              Row* row = new Row();
              GetRow(row, stmt->_handle);
              baton->rows.push_back(row);
          }
  
          if (stmt->status != SQLITE_DONE) {
              stmt->message = std::string(sqlite3_errmsg(stmt->db->_handle));
          }
      }
  
      sqlite3_mutex_leave(mtx);
  }
  
  void Statement::Work_AfterAll(uv_work_t* req) {
      Nan::HandleScope scope;
  
      STATEMENT_INIT(RowsBaton);
  
      if (stmt->status != SQLITE_DONE) {
          Error(baton);
      }
      else {
          // Fire callbacks.
          Local<Function> cb = Nan::New(baton->callback);
          if (!cb.IsEmpty() && cb->IsFunction()) {
              if (baton->rows.size()) {
                  // Create the result array from the data we acquired.
                  Local<Array> result(Nan::New<Array>(baton->rows.size()));
                  Rows::const_iterator it = baton->rows.begin();
                  Rows::const_iterator end = baton->rows.end();
                  for (int i = 0; it < end; ++it, i++) {
                      Nan::Set(result, i, RowToJS(*it));
                      delete *it;
                  }
  
                  Local<Value> argv[] = { Nan::Null(), result };
                  TRY_CATCH_CALL(stmt->handle(), cb, 2, argv);
              }
              else {
                  // There were no result rows.
                  Local<Value> argv[] = {
                      Nan::Null(),
                      Nan::New<Array>(0)
                  };
                  TRY_CATCH_CALL(stmt->handle(), cb, 2, argv);
              }
          }
      }
  
      STATEMENT_END();
  }
  
  NAN_METHOD(Statement::Each) {
      Statement* stmt = Nan::ObjectWrap::Unwrap<Statement>(info.This());
  
      int last = info.Length();
  
      Local<Function> completed;
      if (last >= 2 && info[last - 1]->IsFunction() && info[last - 2]->IsFunction()) {
          completed = Local<Function>::Cast(info[--last]);
      }
  
      EachBaton* baton = stmt->Bind<EachBaton>(info, 0, last);
      if (baton == NULL) {
          return Nan::ThrowError("Data type is not supported");
      }
      else {
          baton->completed.Reset(completed);
          stmt->Schedule(Work_BeginEach, baton);
          info.GetReturnValue().Set(info.This());
      }
  }
  
  void Statement::Work_BeginEach(Baton* baton) {
      // Only create the Async object when we're actually going into
      // the event loop. This prevents dangling events.
      EachBaton* each_baton = static_cast<EachBaton*>(baton);
      each_baton->async = new Async(each_baton->stmt, reinterpret_cast<uv_async_cb>(AsyncEach), baton->loop);
      each_baton->async->item_cb.Reset(each_baton->callback);
      each_baton->async->completed_cb.Reset(each_baton->completed);
  
      STATEMENT_BEGIN(Each);
  }
  
  void Statement::Work_Each(uv_work_t* req) {
      STATEMENT_INIT(EachBaton);
  
      Async* async = baton->async;
  
      sqlite3_mutex* mtx = sqlite3_db_mutex(stmt->db->_handle);
  
      int retrieved = 0;
  
      // Make sure that we also reset when there are no parameters.
      if (!baton->parameters.size()) {
          sqlite3_reset(stmt->_handle);
      }
  
      if (stmt->Bind(baton->parameters)) {
          while (true) {
              sqlite3_mutex_enter(mtx);
              stmt->status = sqlite3_step(stmt->_handle);
              if (stmt->status == SQLITE_ROW) {
                  sqlite3_mutex_leave(mtx);
                  Row* row = new Row();
                  GetRow(row, stmt->_handle);
                  NODE_SQLITE3_MUTEX_LOCK(&async->mutex)
                  async->data.push_back(row);
                  retrieved++;
                  NODE_SQLITE3_MUTEX_UNLOCK(&async->mutex)
  
                  uv_async_send(&async->watcher);
              }
              else {
                  if (stmt->status != SQLITE_DONE) {
                      stmt->message = std::string(sqlite3_errmsg(stmt->db->_handle));
                  }
                  sqlite3_mutex_leave(mtx);
                  break;
              }
          }
      }
  
      async->completed = true;
      uv_async_send(&async->watcher);
  }
  
  void Statement::CloseCallback(uv_handle_t* handle) {
      assert(handle != NULL);
      assert(handle->data != NULL);
      Async* async = static_cast<Async*>(handle->data);
      delete async;
  }
  
  void Statement::AsyncEach(uv_async_t* handle, int status) {
      Nan::HandleScope scope;
  
      Async* async = static_cast<Async*>(handle->data);
  
      while (true) {
          // Get the contents out of the data cache for us to process in the JS callback.
          Rows rows;
          NODE_SQLITE3_MUTEX_LOCK(&async->mutex)
          rows.swap(async->data);
          NODE_SQLITE3_MUTEX_UNLOCK(&async->mutex)
  
          if (rows.empty()) {
              break;
          }
  
          Local<Function> cb = Nan::New(async->item_cb);
          if (!cb.IsEmpty() && cb->IsFunction()) {
              Local<Value> argv[2];
              argv[0] = Nan::Null();
  
              Rows::const_iterator it = rows.begin();
              Rows::const_iterator end = rows.end();
              for (int i = 0; it < end; ++it, i++) {
                  argv[1] = RowToJS(*it);
                  async->retrieved++;
                  TRY_CATCH_CALL(async->stmt->handle(), cb, 2, argv);
                  delete *it;
              }
          }
      }
  
      Local<Function> cb = Nan::New(async->completed_cb);
      if (async->completed) {
          if (!cb.IsEmpty() &&
                  cb->IsFunction()) {
              Local<Value> argv[] = {
                  Nan::Null(),
                  Nan::New(async->retrieved)
              };
              TRY_CATCH_CALL(async->stmt->handle(), cb, 2, argv);
          }
          uv_close(reinterpret_cast<uv_handle_t*>(handle), CloseCallback);
      }
  }
  
  void Statement::Work_AfterEach(uv_work_t* req) {
      Nan::HandleScope scope;
  
      STATEMENT_INIT(EachBaton);
  
      if (stmt->status != SQLITE_DONE) {
          Error(baton);
      }
  
      STATEMENT_END();
  }
  
  NAN_METHOD(Statement::Reset) {
      Statement* stmt = Nan::ObjectWrap::Unwrap<Statement>(info.This());
  
      OPTIONAL_ARGUMENT_FUNCTION(0, callback);
  
      Environment* env = Environment::GetCurrent(info.GetIsolate());
  
      Baton* baton = new Baton(stmt, callback, env->event_loop());
      stmt->Schedule(Work_BeginReset, baton);
  
      info.GetReturnValue().Set(info.This());
  }
  
  void Statement::Work_BeginReset(Baton* baton) {
      STATEMENT_BEGIN(Reset);
  }
  
  void Statement::Work_Reset(uv_work_t* req) {
      STATEMENT_INIT(Baton);
  
      sqlite3_reset(stmt->_handle);
      stmt->status = SQLITE_OK;
  }
  
  void Statement::Work_AfterReset(uv_work_t* req) {
      Nan::HandleScope scope;
  
      STATEMENT_INIT(Baton);
  
      // Fire callbacks.
      Local<Function> cb = Nan::New(baton->callback);
      if (!cb.IsEmpty() && cb->IsFunction()) {
          Local<Value> argv[] = { Nan::Null() };
          TRY_CATCH_CALL(stmt->handle(), cb, 1, argv);
      }
  
      STATEMENT_END();
  }
  
  Local<Object> Statement::RowToJS(Row* row) {
      Nan::EscapableHandleScope scope;
  
      Local<Object> result = Nan::New<Object>();
  
      Row::const_iterator it = row->begin();
      Row::const_iterator end = row->end();
      for (int i = 0; it < end; ++it, i++) {
          Values::Field* field = *it;
  
          Local<Value> value;
  
          switch (field->type) {
              case SQLITE_INTEGER: {
                  value = Nan::New<Number>(((Values::Integer*)field)->value);
              } break;
              case SQLITE_FLOAT: {
                  value = Nan::New<Number>(((Values::Float*)field)->value);
              } break;
              case SQLITE_TEXT: {
                  value = Nan::New<String>(((Values::Text*)field)->value.c_str(), ((Values::Text*)field)->value.size()).ToLocalChecked();
              } break;
              case SQLITE_BLOB: {
                  value = Nan::CopyBuffer(((Values::Blob*)field)->value, ((Values::Blob*)field)->length).ToLocalChecked();
              } break;
              case SQLITE_NULL: {
                  value = Nan::Null();
              } break;
          }
  
          Nan::Set(result, Nan::New(field->name.c_str()).ToLocalChecked(), value);
  
          DELETE_FIELD(field);
      }
  
      return scope.Escape(result);
  }
  
  void Statement::GetRow(Row* row, sqlite3_stmt* stmt) {
      int rows = sqlite3_column_count(stmt);
  
      for (int i = 0; i < rows; i++) {
          int type = sqlite3_column_type(stmt, i);
          const char* name = sqlite3_column_name(stmt, i);
          switch (type) {
              case SQLITE_INTEGER: {
                  row->push_back(new Values::Integer(name, sqlite3_column_int64(stmt, i)));
              }   break;
              case SQLITE_FLOAT: {
                  row->push_back(new Values::Float(name, sqlite3_column_double(stmt, i)));
              }   break;
              case SQLITE_TEXT: {
                  const char* text = (const char*)sqlite3_column_text(stmt, i);
                  int length = sqlite3_column_bytes(stmt, i);
                  row->push_back(new Values::Text(name, length, text));
              } break;
              case SQLITE_BLOB: {
                  const void* blob = sqlite3_column_blob(stmt, i);
                  int length = sqlite3_column_bytes(stmt, i);
                  row->push_back(new Values::Blob(name, length, blob));
              }   break;
              case SQLITE_NULL: {
                  row->push_back(new Values::Null(name));
              }   break;
              default:
                  assert(false);
          }
      }
  }
  
  NAN_METHOD(Statement::Finalize) {
      Statement* stmt = Nan::ObjectWrap::Unwrap<Statement>(info.This());
      OPTIONAL_ARGUMENT_FUNCTION(0, callback);
  
      Environment* env = Environment::GetCurrent(info.GetIsolate());
  
      Baton* baton = new Baton(stmt, callback, env->event_loop());
      stmt->Schedule(Finalize, baton);
  
      info.GetReturnValue().Set(stmt->db->handle());
  }
  
  void Statement::Finalize(Baton* baton) {
      Nan::HandleScope scope;
  
      baton->stmt->Finalize();
  
      // Fire callback in case there was one.
      Local<Function> cb = Nan::New(baton->callback);
      if (!cb.IsEmpty() && cb->IsFunction()) {
          TRY_CATCH_CALL(baton->stmt->handle(), cb, 0, NULL);
      }
  
      delete baton;
  }
  
  void Statement::Finalize() {
      assert(!finalized);
      finalized = true;
      CleanQueue();
      // Finalize returns the status code of the last operation. We already fired
      // error events in case those failed.
      sqlite3_finalize(_handle);
      _handle = NULL;
      db->Unref();
  }
  
  void Statement::CleanQueue() {
      Nan::HandleScope scope;
  
      if (prepared && !queue.empty()) {
          // This statement has already been prepared and is now finalized.
          // Fire error for all remaining items in the queue.
          EXCEPTION(Nan::New<String>("Statement is already finalized").ToLocalChecked(), SQLITE_MISUSE, exception);
          Local<Value> argv[] = { exception };
          bool called = false;
  
          // Clear out the queue so that this object can get GC'ed.
          while (!queue.empty()) {
              Call* call = queue.front();
              queue.pop();
  
              Local<Function> cb = Nan::New(call->baton->callback);
  
              if (prepared && !cb.IsEmpty() &&
                  cb->IsFunction()) {
                  TRY_CATCH_CALL(handle(), cb, 1, argv);
                  called = true;
              }
  
              // We don't call the actual callback, so we have to make sure that
              // the baton gets destroyed.
              delete call->baton;
              delete call;
          }
  
          // When we couldn't call a callback function, emit an error on the
          // Statement object.
          if (!called) {
              Local<Value> info[] = { Nan::New("error").ToLocalChecked(), exception };
              EMIT_EVENT(handle(), 2, info);
          }
      }
      else while (!queue.empty()) {
          // Just delete all items in the queue; we already fired an event when
          // preparing the statement failed.
          Call* call = queue.front();
          queue.pop();
  
          // We don't call the actual callback, so we have to make sure that
          // the baton gets destroyed.
          delete call->baton;
          delete call;
      }
  }
  