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/*
*
* 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_CLIENT_CONFIG_LB_POLICY_H
#define GRPC_INTERNAL_CORE_CLIENT_CONFIG_LB_POLICY_H
#include "src/core/client_config/subchannel.h"
/** A load balancing policy: specified by a vtable and a struct (which
is expected to be extended to contain some parameters) */
typedef struct grpc_lb_policy grpc_lb_policy;
typedef struct grpc_lb_policy_vtable grpc_lb_policy_vtable;
typedef void (*grpc_lb_completion)(void *cb_arg, grpc_subchannel *subchannel,
grpc_status_code status, const char *errmsg);
struct grpc_lb_policy {
const grpc_lb_policy_vtable *vtable;
gpr_refcount refs;
};
struct grpc_lb_policy_vtable {
void (*destroy)(grpc_lb_policy *policy);
void (*shutdown)(grpc_lb_policy *policy);
/** implement grpc_lb_policy_pick */
void (*pick)(grpc_lb_policy *policy, grpc_pollset *pollset,
grpc_metadata_batch *initial_metadata, grpc_subchannel **target,
grpc_iomgr_closure *on_complete);
/** try to enter a READY connectivity state */
void (*exit_idle)(grpc_lb_policy *policy);
/** broadcast a transport op to all subchannels */
void (*broadcast)(grpc_lb_policy *policy, grpc_transport_op *op);
/** check the current connectivity of the lb_policy */
grpc_connectivity_state (*check_connectivity)(grpc_lb_policy *policy);
/** call notify when the connectivity state of a channel changes from *state.
Updates *state with the new state of the policy */
void (*notify_on_state_change)(grpc_lb_policy *policy,
grpc_connectivity_state *state,
grpc_iomgr_closure *closure);
};
#ifdef GRPC_LB_POLICY_REFCOUNT_DEBUG
#define GRPC_LB_POLICY_REF(p, r) \
grpc_lb_policy_ref((p), __FILE__, __LINE__, (r))
#define GRPC_LB_POLICY_UNREF(p, r) \
grpc_lb_policy_unref((p), __FILE__, __LINE__, (r))
void grpc_lb_policy_ref(grpc_lb_policy *policy, const char *file, int line,
const char *reason);
void grpc_lb_policy_unref(grpc_lb_policy *policy, const char *file, int line,
const char *reason);
#else
#define GRPC_LB_POLICY_REF(p, r) grpc_lb_policy_ref((p))
#define GRPC_LB_POLICY_UNREF(p, r) grpc_lb_policy_unref((p))
void grpc_lb_policy_ref(grpc_lb_policy *policy);
void grpc_lb_policy_unref(grpc_lb_policy *policy);
#endif
/** called by concrete implementations to initialize the base struct */
void grpc_lb_policy_init(grpc_lb_policy *policy,
const grpc_lb_policy_vtable *vtable);
/** Start shutting down (fail any pending picks) */
void grpc_lb_policy_shutdown(grpc_lb_policy *policy);
/** Given initial metadata in \a initial_metadata, find an appropriate
target for this rpc, and 'return' it by calling \a on_complete after setting
\a target.
Picking can be asynchronous. Any IO should be done under \a pollset. */
void grpc_lb_policy_pick(grpc_lb_policy *policy, grpc_pollset *pollset,
grpc_metadata_batch *initial_metadata,
grpc_subchannel **target,
grpc_iomgr_closure *on_complete);
void grpc_lb_policy_broadcast(grpc_lb_policy *policy, grpc_transport_op *op);
void grpc_lb_policy_exit_idle(grpc_lb_policy *policy);
void grpc_lb_policy_notify_on_state_change(grpc_lb_policy *policy,
grpc_connectivity_state *state,
grpc_iomgr_closure *closure);
grpc_connectivity_state grpc_lb_policy_check_connectivity(
grpc_lb_policy *policy);
#endif /* GRPC_INTERNAL_CORE_CONFIG_LB_POLICY_H */
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