//
// Copyright 2015 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

#ifndef GRPC_CORE_LIB_IOMGR_RESOLVE_ADDRESS_IMPL_H
#define GRPC_CORE_LIB_IOMGR_RESOLVE_ADDRESS_IMPL_H

#include <grpc/support/port_platform.h>

#include <stddef.h>

#include "src/core/lib/iomgr/port.h"
#include "src/core/lib/iomgr/resolve_address.h"

namespace grpc_core {

// A fire and forget class used by DNSResolver::Request implementations to
// schedule DNS  resolution callbacks on the ExecCtx, which is frequently
// necessary to avoid lock inversion related problems.
class DNSCallbackExecCtxScheduler {
 public:
  DNSCallbackExecCtxScheduler(
      std::function<void(absl::StatusOr<std::vector<grpc_resolved_address>>)>
          on_done,
      absl::StatusOr<std::vector<grpc_resolved_address>> param)
      : on_done_(std::move(on_done)), param_(std::move(param)) {
    GRPC_CLOSURE_INIT(&closure_, RunCallback, this, grpc_schedule_on_exec_ctx);
    ExecCtx::Run(DEBUG_LOCATION, &closure_, GRPC_ERROR_NONE);
  }

 private:
  static void RunCallback(void* arg, grpc_error_handle /* error */) {
    DNSCallbackExecCtxScheduler* self =
        static_cast<DNSCallbackExecCtxScheduler*>(arg);
    self->on_done_(std::move(self->param_));
    delete self;
  }

  const std::function<void(absl::StatusOr<std::vector<grpc_resolved_address>>)>
      on_done_;
  absl::StatusOr<std::vector<grpc_resolved_address>> param_;
  grpc_closure closure_;
};

}  // namespace grpc_core

#endif /* GRPC_CORE_LIB_IOMGR_RESOLVE_ADDRESS_IMPL_H */
