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/*
*
* 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_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_FACTORY_H
#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_FACTORY_H
#include <grpc/support/port_platform.h>
#include "src/core/lib/iomgr/resolve_address.h"
#include "src/core/ext/filters/client_channel/client_channel_factory.h"
#include "src/core/ext/filters/client_channel/lb_policy.h"
#include "src/core/lib/uri/uri_parser.h"
//
// representation of an LB address
//
// Channel arg key for grpc_lb_addresses.
#define GRPC_ARG_LB_ADDRESSES "grpc.lb_addresses"
/** A resolved address alongside any LB related information associated with it.
* \a user_data, if not NULL, contains opaque data meant to be consumed by the
* gRPC LB policy. Note that no all LB policies support \a user_data as input.
* Those who don't will simply ignore it and will correspondingly return NULL in
* their namesake pick() output argument. */
// TODO(roth): Once we figure out a better way of handling user_data in
// LB policies, convert these structs to C++ classes.
typedef struct grpc_lb_address {
grpc_resolved_address address;
bool is_balancer;
char* balancer_name; /* For secure naming. */
void* user_data;
} grpc_lb_address;
typedef struct grpc_lb_user_data_vtable {
void* (*copy)(void*);
void (*destroy)(void*);
int (*cmp)(void*, void*);
} grpc_lb_user_data_vtable;
typedef struct grpc_lb_addresses {
size_t num_addresses;
grpc_lb_address* addresses;
const grpc_lb_user_data_vtable* user_data_vtable;
} grpc_lb_addresses;
/** Returns a grpc_addresses struct with enough space for
\a num_addresses addresses. The \a user_data_vtable argument may be
NULL if no user data will be added. */
grpc_lb_addresses* grpc_lb_addresses_create(
size_t num_addresses, const grpc_lb_user_data_vtable* user_data_vtable);
/** Creates a copy of \a addresses. */
grpc_lb_addresses* grpc_lb_addresses_copy(const grpc_lb_addresses* addresses);
/** Sets the value of the address at index \a index of \a addresses.
* \a address is a socket address of length \a address_len. */
void grpc_lb_addresses_set_address(grpc_lb_addresses* addresses, size_t index,
const void* address, size_t address_len,
bool is_balancer, const char* balancer_name,
void* user_data);
/** Sets the value of the address at index \a index of \a addresses from \a uri.
* Returns true upon success, false otherwise. */
bool grpc_lb_addresses_set_address_from_uri(grpc_lb_addresses* addresses,
size_t index, const grpc_uri* uri,
bool is_balancer,
const char* balancer_name,
void* user_data);
/** Compares \a addresses1 and \a addresses2. */
int grpc_lb_addresses_cmp(const grpc_lb_addresses* addresses1,
const grpc_lb_addresses* addresses2);
/** Destroys \a addresses. */
void grpc_lb_addresses_destroy(grpc_lb_addresses* addresses);
/** Returns a channel arg containing \a addresses. */
grpc_arg grpc_lb_addresses_create_channel_arg(
const grpc_lb_addresses* addresses);
/** Returns the \a grpc_lb_addresses instance in \a channel_args or NULL */
grpc_lb_addresses* grpc_lb_addresses_find_channel_arg(
const grpc_channel_args* channel_args);
// Returns true if addresses contains at least one balancer address.
bool grpc_lb_addresses_contains_balancer_address(
const grpc_lb_addresses& addresses);
//
// LB policy factory
//
namespace grpc_core {
class LoadBalancingPolicyFactory {
public:
/// Returns a new LB policy instance.
virtual OrphanablePtr<LoadBalancingPolicy> CreateLoadBalancingPolicy(
const LoadBalancingPolicy::Args& args) const GRPC_ABSTRACT;
/// Returns the LB policy name that this factory provides.
/// Caller does NOT take ownership of result.
virtual const char* name() const GRPC_ABSTRACT;
virtual ~LoadBalancingPolicyFactory() {}
GRPC_ABSTRACT_BASE_CLASS
};
} // namespace grpc_core
#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_FACTORY_H */
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