/*
 *
 * 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_ENDPOINT_H
#define GRPC_CORE_LIB_IOMGR_ENDPOINT_H

#include <grpc/support/port_platform.h>

#include "absl/strings/string_view.h"

#include <grpc/slice.h>
#include <grpc/slice_buffer.h>
#include <grpc/support/time.h>
#include "src/core/lib/iomgr/pollset.h"
#include "src/core/lib/iomgr/pollset_set.h"
#include "src/core/lib/iomgr/resource_quota.h"

/* An endpoint caps a streaming channel between two communicating processes.
   Examples may be: a tcp socket, <stdin+stdout>, or some shared memory. */

typedef struct grpc_endpoint grpc_endpoint;
typedef struct grpc_endpoint_vtable grpc_endpoint_vtable;

struct grpc_endpoint_vtable {
  void (*read)(grpc_endpoint* ep, grpc_slice_buffer* slices, grpc_closure* cb,
               bool urgent);
  void (*write)(grpc_endpoint* ep, grpc_slice_buffer* slices, grpc_closure* cb,
                void* arg);
  void (*add_to_pollset)(grpc_endpoint* ep, grpc_pollset* pollset);
  void (*add_to_pollset_set)(grpc_endpoint* ep, grpc_pollset_set* pollset);
  void (*delete_from_pollset_set)(grpc_endpoint* ep, grpc_pollset_set* pollset);
  void (*shutdown)(grpc_endpoint* ep, grpc_error* why);
  void (*destroy)(grpc_endpoint* ep);
  grpc_resource_user* (*get_resource_user)(grpc_endpoint* ep);
  absl::string_view (*get_peer)(grpc_endpoint* ep);
  absl::string_view (*get_local_address)(grpc_endpoint* ep);
  int (*get_fd)(grpc_endpoint* ep);
  bool (*can_track_err)(grpc_endpoint* ep);
};

/* When data is available on the connection, calls the callback with slices.
   Callback success indicates that the endpoint can accept more reads, failure
   indicates the endpoint is closed.
   Valid slices may be placed into \a slices even when the callback is
   invoked with error != GRPC_ERROR_NONE. */
void grpc_endpoint_read(grpc_endpoint* ep, grpc_slice_buffer* slices,
                        grpc_closure* cb, bool urgent);

absl::string_view grpc_endpoint_get_peer(grpc_endpoint* ep);

absl::string_view grpc_endpoint_get_local_address(grpc_endpoint* ep);

/* Get the file descriptor used by \a ep. Return -1 if \a ep is not using an fd.
 */
int grpc_endpoint_get_fd(grpc_endpoint* ep);

/* Write slices out to the socket.

   If the connection is ready for more data after the end of the call, it
   returns GRPC_ENDPOINT_DONE.
   Otherwise it returns GRPC_ENDPOINT_PENDING and calls cb when the
   connection is ready for more data.
   \a slices may be mutated at will by the endpoint until cb is called.
   No guarantee is made to the content of slices after a write EXCEPT that
   it is a valid slice buffer.
   \a arg is platform specific. It is currently only used by TCP on linux
   platforms as an argument that would be forwarded to the timestamps callback.
   */
void grpc_endpoint_write(grpc_endpoint* ep, grpc_slice_buffer* slices,
                         grpc_closure* cb, void* arg);

/* Causes any pending and future read/write callbacks to run immediately with
   success==0 */
void grpc_endpoint_shutdown(grpc_endpoint* ep, grpc_error* why);
void grpc_endpoint_destroy(grpc_endpoint* ep);

/* Add an endpoint to a pollset or pollset_set, so that when the pollset is
   polled, events from this endpoint are considered */
void grpc_endpoint_add_to_pollset(grpc_endpoint* ep, grpc_pollset* pollset);
void grpc_endpoint_add_to_pollset_set(grpc_endpoint* ep,
                                      grpc_pollset_set* pollset_set);

/* Delete an endpoint from a pollset_set */
void grpc_endpoint_delete_from_pollset_set(grpc_endpoint* ep,
                                           grpc_pollset_set* pollset_set);

grpc_resource_user* grpc_endpoint_get_resource_user(grpc_endpoint* endpoint);

bool grpc_endpoint_can_track_err(grpc_endpoint* ep);

struct grpc_endpoint {
  const grpc_endpoint_vtable* vtable;
};

#endif /* GRPC_CORE_LIB_IOMGR_ENDPOINT_H */
