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 *
 * Copyright 2015, Google Inc.
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 * modification, are permitted provided that the following conditions are
 * met:
 *
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 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
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#ifndef GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_H
#define GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_H

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

typedef enum grpc_endpoint_op_status {
  GRPC_ENDPOINT_DONE,    /* completed immediately, cb won't be called */
  GRPC_ENDPOINT_PENDING, /* cb will be called when completed */
  GRPC_ENDPOINT_ERROR    /* write errored out, cb won't be called */
} grpc_endpoint_op_status;

struct grpc_endpoint_vtable {
  grpc_endpoint_op_status (*read)(grpc_endpoint *ep, gpr_slice_buffer *slices,
                                  grpc_iomgr_closure *cb);
  grpc_endpoint_op_status (*write)(grpc_endpoint *ep, gpr_slice_buffer *slices,
                                   grpc_iomgr_closure *cb);
  void (*add_to_pollset)(grpc_endpoint *ep, grpc_pollset *pollset);
  void (*add_to_pollset_set)(grpc_endpoint *ep, grpc_pollset_set *pollset);
  void (*shutdown)(grpc_endpoint *ep);
  void (*destroy)(grpc_endpoint *ep);
  char *(*get_peer)(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 on callback success == 0. */
grpc_endpoint_op_status grpc_endpoint_read(
    grpc_endpoint *ep, gpr_slice_buffer *slices,
    grpc_iomgr_closure *cb) GRPC_MUST_USE_RESULT;

char *grpc_endpoint_get_peer(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.
   */
grpc_endpoint_op_status grpc_endpoint_write(
    grpc_endpoint *ep, gpr_slice_buffer *slices,
    grpc_iomgr_closure *cb) GRPC_MUST_USE_RESULT;

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

/* Add an endpoint to a pollset, 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);

struct grpc_endpoint {
  const grpc_endpoint_vtable *vtable;
};

#endif /* GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_H */