/*
 *
 * Copyright 2017 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.
 *
 */


// Package roundrobin defines a roundrobin balancer. Roundrobin balancer is
// installed as one of the default balancers in gRPC, users don't need to
// explicitly install this balancer.
package roundrobin

import (
	

	
	
	
	
)

// Name is the name of round_robin balancer.
const Name = "round_robin"

var logger = grpclog.Component("roundrobin")

// newBuilder creates a new roundrobin balancer builder.
func () balancer.Builder {
	return base.NewBalancerBuilder(Name, &rrPickerBuilder{}, base.Config{HealthCheck: true})
}

func () {
	balancer.Register(newBuilder())
}

type rrPickerBuilder struct{}

func (*rrPickerBuilder) ( base.PickerBuildInfo) balancer.Picker {
	logger.Infof("roundrobinPicker: Build called with info: %v", )
	if len(.ReadySCs) == 0 {
		return base.NewErrPicker(balancer.ErrNoSubConnAvailable)
	}
	 := make([]balancer.SubConn, 0, len(.ReadySCs))
	for  := range .ReadySCs {
		 = append(, )
	}
	return &rrPicker{
		subConns: ,
		// Start at a random index, as the same RR balancer rebuilds a new
		// picker when SubConn states change, and we don't want to apply excess
		// load to the first server in the list.
		next: uint32(grpcrand.Intn(len())),
	}
}

type rrPicker struct {
	// subConns is the snapshot of the roundrobin balancer when this picker was
	// created. The slice is immutable. Each Get() will do a round robin
	// selection from it and return the selected SubConn.
	subConns []balancer.SubConn
	next     uint32
}

func ( *rrPicker) (balancer.PickInfo) (balancer.PickResult, error) {
	 := uint32(len(.subConns))
	 := atomic.AddUint32(&.next, 1)

	 := .subConns[%]
	return balancer.PickResult{SubConn: }, nil
}