/*
 *
 * Copyright 2015, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CONNECTIVITY_STATE_H
#define GRPC_INTERNAL_CORE_TRANSPORT_CONNECTIVITY_STATE_H

#include <grpc/grpc.h>
#include "src/core/iomgr/exec_ctx.h"

typedef struct grpc_connectivity_state_watcher {
  /** we keep watchers in a linked list */
  struct grpc_connectivity_state_watcher *next;
  /** closure to notify on change */
  grpc_closure *notify;
  /** the current state as believed by the watcher */
  grpc_connectivity_state *current;
} grpc_connectivity_state_watcher;

typedef struct {
  /** current connectivity state */
  grpc_connectivity_state current_state;
  /** all our watchers */
  grpc_connectivity_state_watcher *watchers;
  /** a name to help debugging */
  char *name;
} grpc_connectivity_state_tracker;

extern int grpc_connectivity_state_trace;

void grpc_connectivity_state_init(grpc_connectivity_state_tracker *tracker,
                                  grpc_connectivity_state init_state,
                                  const char *name);
void grpc_connectivity_state_destroy(grpc_exec_ctx *exec_ctx,
                                     grpc_connectivity_state_tracker *tracker);

/** Set connectivity state; not thread safe; access must be serialized with an
 * external lock */
void grpc_connectivity_state_set(grpc_exec_ctx *exec_ctx,
                                 grpc_connectivity_state_tracker *tracker,
                                 grpc_connectivity_state state,
                                 const char *reason);

grpc_connectivity_state grpc_connectivity_state_check(
    grpc_connectivity_state_tracker *tracker);

/** Return 1 if the channel should start connecting, 0 otherwise */
int grpc_connectivity_state_notify_on_state_change(
    grpc_exec_ctx *exec_ctx, grpc_connectivity_state_tracker *tracker,
    grpc_connectivity_state *current, grpc_closure *notify);

/** Remove \a subscribed_notify from the list of closures to be called on a
 * state change if present, returning 1. Otherwise, nothing is done and return
 * 0. */
int grpc_connectivity_state_change_unsubscribe(
    grpc_exec_ctx *exec_ctx, grpc_connectivity_state_tracker *tracker,
    grpc_closure *subscribed_notify);

#endif /* GRPC_INTERNAL_CORE_TRANSPORT_CONNECTIVITY_STATE_H */