/*
 *
 * 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 grpc

import (
	
	
	

	
	
	
	
	
	
)

// ccResolverWrapper is a wrapper on top of cc for resolvers.
// It implements resolver.ClientConn interface.
type ccResolverWrapper struct {
	// The following fields are initialized when the wrapper is created and are
	// read-only afterwards, and therefore can be accessed without a mutex.
	cc                  *ClientConn
	ignoreServiceConfig bool
	serializer          *grpcsync.CallbackSerializer
	serializerCancel    context.CancelFunc

	resolver resolver.Resolver // only accessed within the serializer

	// The following fields are protected by mu.  Caller must take cc.mu before
	// taking mu.
	mu       sync.Mutex
	curState resolver.State
	closed   bool
}

// newCCResolverWrapper initializes the ccResolverWrapper.  It can only be used
// after calling start, which builds the resolver.
func newCCResolverWrapper( *ClientConn) *ccResolverWrapper {
	,  := context.WithCancel(.ctx)
	return &ccResolverWrapper{
		cc:                  ,
		ignoreServiceConfig: .dopts.disableServiceConfig,
		serializer:          grpcsync.NewCallbackSerializer(),
		serializerCancel:    ,
	}
}

// start builds the name resolver using the resolver.Builder in cc and returns
// any error encountered.  It must always be the first operation performed on
// any newly created ccResolverWrapper, except that close may be called instead.
func ( *ccResolverWrapper) () error {
	 := make(chan error)
	.serializer.TrySchedule(func( context.Context) {
		if .Err() != nil {
			return
		}
		 := resolver.BuildOptions{
			DisableServiceConfig: .cc.dopts.disableServiceConfig,
			DialCreds:            .cc.dopts.copts.TransportCredentials,
			CredsBundle:          .cc.dopts.copts.CredsBundle,
			Dialer:               .cc.dopts.copts.Dialer,
			Authority:            .cc.authority,
			MetricsRecorder:      .cc.metricsRecorderList,
		}
		var  error
		// The delegating resolver is used unless:
		//   - A custom dialer is provided via WithContextDialer dialoption or
		//   - Proxy usage is disabled through WithNoProxy dialoption.
		// In these cases, the resolver is built based on the scheme of target,
		// using the appropriate resolver builder.
		if .cc.dopts.copts.Dialer != nil || !.cc.dopts.useProxy {
			.resolver,  = .cc.resolverBuilder.Build(.cc.parsedTarget, , )
		} else {
			.resolver,  = delegatingresolver.New(.cc.parsedTarget, , , .cc.resolverBuilder, .cc.dopts.enableLocalDNSResolution)
		}
		 <- 
	})
	return <-
}

func ( *ccResolverWrapper) ( resolver.ResolveNowOptions) {
	.serializer.TrySchedule(func( context.Context) {
		if .Err() != nil || .resolver == nil {
			return
		}
		.resolver.ResolveNow()
	})
}

// close initiates async shutdown of the wrapper.  To determine the wrapper has
// finished shutting down, the channel should block on ccr.serializer.Done()
// without cc.mu held.
func ( *ccResolverWrapper) () {
	channelz.Info(logger, .cc.channelz, "Closing the name resolver")
	.mu.Lock()
	.closed = true
	.mu.Unlock()

	.serializer.TrySchedule(func(context.Context) {
		if .resolver == nil {
			return
		}
		.resolver.Close()
		.resolver = nil
	})
	.serializerCancel()
}

// UpdateState is called by resolver implementations to report new state to gRPC
// which includes addresses and service config.
func ( *ccResolverWrapper) ( resolver.State) error {
	.cc.mu.Lock()
	.mu.Lock()
	if .closed {
		.mu.Unlock()
		.cc.mu.Unlock()
		return nil
	}
	if .Endpoints == nil {
		.Endpoints = addressesToEndpoints(.Addresses)
	}
	.addChannelzTraceEvent()
	.curState = 
	.mu.Unlock()
	return .cc.updateResolverStateAndUnlock(, nil)
}

// ReportError is called by resolver implementations to report errors
// encountered during name resolution to gRPC.
func ( *ccResolverWrapper) ( error) {
	.cc.mu.Lock()
	.mu.Lock()
	if .closed {
		.mu.Unlock()
		.cc.mu.Unlock()
		return
	}
	.mu.Unlock()
	channelz.Warningf(logger, .cc.channelz, "ccResolverWrapper: reporting error to cc: %v", )
	.cc.updateResolverStateAndUnlock(resolver.State{}, )
}

// NewAddress is called by the resolver implementation to send addresses to
// gRPC.
func ( *ccResolverWrapper) ( []resolver.Address) {
	.cc.mu.Lock()
	.mu.Lock()
	if .closed {
		.mu.Unlock()
		.cc.mu.Unlock()
		return
	}
	 := resolver.State{
		Addresses:     ,
		ServiceConfig: .curState.ServiceConfig,
		Endpoints:     addressesToEndpoints(),
	}
	.addChannelzTraceEvent()
	.curState = 
	.mu.Unlock()
	.cc.updateResolverStateAndUnlock(, nil)
}

// ParseServiceConfig is called by resolver implementations to parse a JSON
// representation of the service config.
func ( *ccResolverWrapper) ( string) *serviceconfig.ParseResult {
	return parseServiceConfig(, .cc.dopts.maxCallAttempts)
}

// addChannelzTraceEvent adds a channelz trace event containing the new
// state received from resolver implementations.
func ( *ccResolverWrapper) ( resolver.State) {
	if !logger.V(0) && !channelz.IsOn() {
		return
	}
	var  []string
	var ,  *ServiceConfig
	var ,  bool
	if .curState.ServiceConfig != nil {
		,  = .curState.ServiceConfig.Config.(*ServiceConfig)
	}
	if .ServiceConfig != nil {
		,  = .ServiceConfig.Config.(*ServiceConfig)
	}
	if  !=  || ( &&  && .rawJSONString != .rawJSONString) {
		 = append(, "service config updated")
	}
	if len(.curState.Addresses) > 0 && len(.Addresses) == 0 {
		 = append(, "resolver returned an empty address list")
	} else if len(.curState.Addresses) == 0 && len(.Addresses) > 0 {
		 = append(, "resolver returned new addresses")
	}
	channelz.Infof(logger, .cc.channelz, "Resolver state updated: %s (%v)", pretty.ToJSON(), strings.Join(, "; "))
}

func addressesToEndpoints( []resolver.Address) []resolver.Endpoint {
	 := make([]resolver.Endpoint, 0, len())
	for ,  := range  {
		 := resolver.Endpoint{Addresses: []resolver.Address{}, Attributes: .BalancerAttributes}
		.Addresses[0].BalancerAttributes = nil
		 = append(, )
	}
	return 
}