412 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			Go
		
	
	
			
		
		
	
	
			412 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			Go
		
	
	
/*
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 *
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 * Copyright 2014, Google Inc.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions are
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 * met:
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 *
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 *     * Redistributions of source code must retain the above copyright
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 * notice, this list of conditions and the following disclaimer.
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 *     * Redistributions in binary form must reproduce the above
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 * copyright notice, this list of conditions and the following disclaimer
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 * in the documentation and/or other materials provided with the
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 * distribution.
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 *     * Neither the name of Google Inc. nor the names of its
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 * contributors may be used to endorse or promote products derived from
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 * this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 *
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 */
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package grpc
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import (
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	"bytes"
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	"errors"
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	"io"
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	"sync"
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	"time"
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	"golang.org/x/net/context"
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	"golang.org/x/net/trace"
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	"google.golang.org/grpc/codes"
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	"google.golang.org/grpc/metadata"
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	"google.golang.org/grpc/transport"
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)
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type streamHandler func(srv interface{}, stream ServerStream) error
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// StreamDesc represents a streaming RPC service's method specification.
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type StreamDesc struct {
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	StreamName string
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	Handler    streamHandler
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	// At least one of these is true.
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	ServerStreams bool
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	ClientStreams bool
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}
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// Stream defines the common interface a client or server stream has to satisfy.
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type Stream interface {
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	// Context returns the context for this stream.
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	Context() context.Context
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	// SendMsg blocks until it sends m, the stream is done or the stream
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	// breaks.
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	// On error, it aborts the stream and returns an RPC status on client
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	// side. On server side, it simply returns the error to the caller.
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	// SendMsg is called by generated code.
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	SendMsg(m interface{}) error
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	// RecvMsg blocks until it receives a message or the stream is
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	// done. On client side, it returns io.EOF when the stream is done. On
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	// any other error, it aborts the stream and returns an RPC status. On
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	// server side, it simply returns the error to the caller.
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	RecvMsg(m interface{}) error
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}
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// ClientStream defines the interface a client stream has to satify.
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type ClientStream interface {
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	// Header returns the header metedata received from the server if there
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	// is any. It blocks if the metadata is not ready to read.
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	Header() (metadata.MD, error)
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	// Trailer returns the trailer metadata from the server. It must be called
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	// after stream.Recv() returns non-nil error (including io.EOF) for
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	// bi-directional streaming and server streaming or stream.CloseAndRecv()
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	// returns for client streaming in order to receive trailer metadata if
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	// present. Otherwise, it could returns an empty MD even though trailer
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	// is present.
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	Trailer() metadata.MD
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	// CloseSend closes the send direction of the stream. It closes the stream
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	// when non-nil error is met.
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	CloseSend() error
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	Stream
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}
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// NewClientStream creates a new Stream for the client side. This is called
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// by generated code.
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func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
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	var (
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		t   transport.ClientTransport
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		err error
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	)
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	t, err = cc.dopts.picker.Pick(ctx)
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	if err != nil {
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		return nil, toRPCErr(err)
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	}
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	// TODO(zhaoq): CallOption is omitted. Add support when it is needed.
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	callHdr := &transport.CallHdr{
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		Host:   cc.authority,
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		Method: method,
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		Flush:  desc.ServerStreams && desc.ClientStreams,
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	}
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	if cc.dopts.cp != nil {
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		callHdr.SendCompress = cc.dopts.cp.Type()
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	}
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	cs := &clientStream{
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		desc:    desc,
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		codec:   cc.dopts.codec,
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		cp:      cc.dopts.cp,
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		dc:      cc.dopts.dc,
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		tracing: EnableTracing,
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	}
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	if cc.dopts.cp != nil {
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		callHdr.SendCompress = cc.dopts.cp.Type()
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		cs.cbuf = new(bytes.Buffer)
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	}
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	if cs.tracing {
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		cs.trInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
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		cs.trInfo.firstLine.client = true
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		if deadline, ok := ctx.Deadline(); ok {
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			cs.trInfo.firstLine.deadline = deadline.Sub(time.Now())
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		}
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		cs.trInfo.tr.LazyLog(&cs.trInfo.firstLine, false)
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		ctx = trace.NewContext(ctx, cs.trInfo.tr)
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	}
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	s, err := t.NewStream(ctx, callHdr)
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	if err != nil {
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		cs.finish(err)
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		return nil, toRPCErr(err)
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	}
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	cs.t = t
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	cs.s = s
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	cs.p = &parser{r: s}
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	// Listen on ctx.Done() to detect cancellation when there is no pending
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	// I/O operations on this stream.
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	go func() {
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		select {
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		case <-t.Error():
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			// Incur transport error, simply exit.
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		case <-s.Context().Done():
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			err := s.Context().Err()
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			cs.finish(err)
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			cs.closeTransportStream(transport.ContextErr(err))
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		}
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	}()
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	return cs, nil
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}
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// clientStream implements a client side Stream.
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type clientStream struct {
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	t     transport.ClientTransport
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	s     *transport.Stream
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	p     *parser
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	desc  *StreamDesc
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	codec Codec
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	cp    Compressor
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	cbuf  *bytes.Buffer
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	dc    Decompressor
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	tracing bool // set to EnableTracing when the clientStream is created.
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	mu     sync.Mutex
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	closed bool
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	// trInfo.tr is set when the clientStream is created (if EnableTracing is true),
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	// and is set to nil when the clientStream's finish method is called.
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	trInfo traceInfo
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}
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func (cs *clientStream) Context() context.Context {
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	return cs.s.Context()
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}
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func (cs *clientStream) Header() (metadata.MD, error) {
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	m, err := cs.s.Header()
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	if err != nil {
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		if _, ok := err.(transport.ConnectionError); !ok {
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			cs.closeTransportStream(err)
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		}
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	}
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	return m, err
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}
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func (cs *clientStream) Trailer() metadata.MD {
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	return cs.s.Trailer()
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}
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func (cs *clientStream) SendMsg(m interface{}) (err error) {
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	if cs.tracing {
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		cs.mu.Lock()
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		if cs.trInfo.tr != nil {
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			cs.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
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		}
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		cs.mu.Unlock()
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	}
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	defer func() {
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		if err != nil {
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			cs.finish(err)
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		}
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		if err == nil || err == io.EOF {
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			return
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		}
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		if _, ok := err.(transport.ConnectionError); !ok {
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			cs.closeTransportStream(err)
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		}
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		err = toRPCErr(err)
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	}()
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	out, err := encode(cs.codec, m, cs.cp, cs.cbuf)
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	defer func() {
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		if cs.cbuf != nil {
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			cs.cbuf.Reset()
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		}
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	}()
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	if err != nil {
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		return transport.StreamErrorf(codes.Internal, "grpc: %v", err)
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	}
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	return cs.t.Write(cs.s, out, &transport.Options{Last: false})
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}
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func (cs *clientStream) RecvMsg(m interface{}) (err error) {
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	err = recv(cs.p, cs.codec, cs.s, cs.dc, m)
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	defer func() {
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		// err != nil indicates the termination of the stream.
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		if err != nil {
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			cs.finish(err)
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		}
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	}()
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	if err == nil {
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		if cs.tracing {
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			cs.mu.Lock()
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			if cs.trInfo.tr != nil {
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				cs.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
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			}
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			cs.mu.Unlock()
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		}
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		if !cs.desc.ClientStreams || cs.desc.ServerStreams {
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			return
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		}
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		// Special handling for client streaming rpc.
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		err = recv(cs.p, cs.codec, cs.s, cs.dc, m)
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		cs.closeTransportStream(err)
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		if err == nil {
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			return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
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		}
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		if err == io.EOF {
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			if cs.s.StatusCode() == codes.OK {
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				cs.finish(err)
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				return nil
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			}
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			return Errorf(cs.s.StatusCode(), cs.s.StatusDesc())
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		}
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		return toRPCErr(err)
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	}
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	if _, ok := err.(transport.ConnectionError); !ok {
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		cs.closeTransportStream(err)
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	}
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	if err == io.EOF {
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		if cs.s.StatusCode() == codes.OK {
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			// Returns io.EOF to indicate the end of the stream.
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			return
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		}
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		return Errorf(cs.s.StatusCode(), cs.s.StatusDesc())
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	}
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	return toRPCErr(err)
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}
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func (cs *clientStream) CloseSend() (err error) {
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	err = cs.t.Write(cs.s, nil, &transport.Options{Last: true})
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	defer func() {
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		if err != nil {
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			cs.finish(err)
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		}
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	}()
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	if err == nil || err == io.EOF {
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		return
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	}
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	if _, ok := err.(transport.ConnectionError); !ok {
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		cs.closeTransportStream(err)
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	}
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	err = toRPCErr(err)
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	return
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}
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func (cs *clientStream) closeTransportStream(err error) {
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	cs.mu.Lock()
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	if cs.closed {
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		cs.mu.Unlock()
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		return
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	}
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	cs.closed = true
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	cs.mu.Unlock()
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	cs.t.CloseStream(cs.s, err)
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}
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func (cs *clientStream) finish(err error) {
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	if !cs.tracing {
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		return
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	}
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	cs.mu.Lock()
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	defer cs.mu.Unlock()
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	if cs.trInfo.tr != nil {
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		if err == nil || err == io.EOF {
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			cs.trInfo.tr.LazyPrintf("RPC: [OK]")
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		} else {
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			cs.trInfo.tr.LazyPrintf("RPC: [%v]", err)
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			cs.trInfo.tr.SetError()
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		}
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		cs.trInfo.tr.Finish()
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		cs.trInfo.tr = nil
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	}
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}
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// ServerStream defines the interface a server stream has to satisfy.
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type ServerStream interface {
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	// SendHeader sends the header metadata. It should not be called
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	// after SendProto. It fails if called multiple times or if
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	// called after SendProto.
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	SendHeader(metadata.MD) error
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	// SetTrailer sets the trailer metadata which will be sent with the
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	// RPC status.
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	SetTrailer(metadata.MD)
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	Stream
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}
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// serverStream implements a server side Stream.
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type serverStream struct {
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	t          transport.ServerTransport
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	s          *transport.Stream
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	p          *parser
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	codec      Codec
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	cp         Compressor
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	dc         Decompressor
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	cbuf       *bytes.Buffer
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	statusCode codes.Code
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	statusDesc string
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	trInfo     *traceInfo
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	mu sync.Mutex // protects trInfo.tr after the service handler runs.
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}
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func (ss *serverStream) Context() context.Context {
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	return ss.s.Context()
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}
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func (ss *serverStream) SendHeader(md metadata.MD) error {
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	return ss.t.WriteHeader(ss.s, md)
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}
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func (ss *serverStream) SetTrailer(md metadata.MD) {
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	if md.Len() == 0 {
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		return
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	}
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	ss.s.SetTrailer(md)
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	return
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}
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func (ss *serverStream) SendMsg(m interface{}) (err error) {
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	defer func() {
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		if ss.trInfo != nil {
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			ss.mu.Lock()
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			if ss.trInfo.tr != nil {
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				if err == nil {
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					ss.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
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				} else {
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					ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
 | 
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					ss.trInfo.tr.SetError()
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				}
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			}
 | 
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			ss.mu.Unlock()
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		}
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	}()
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	out, err := encode(ss.codec, m, ss.cp, ss.cbuf)
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	defer func() {
 | 
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		if ss.cbuf != nil {
 | 
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			ss.cbuf.Reset()
 | 
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		}
 | 
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	}()
 | 
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	if err != nil {
 | 
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		err = transport.StreamErrorf(codes.Internal, "grpc: %v", err)
 | 
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		return err
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	}
 | 
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	return ss.t.Write(ss.s, out, &transport.Options{Last: false})
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}
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 | 
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func (ss *serverStream) RecvMsg(m interface{}) (err error) {
 | 
						|
	defer func() {
 | 
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		if ss.trInfo != nil {
 | 
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			ss.mu.Lock()
 | 
						|
			if ss.trInfo.tr != nil {
 | 
						|
				if err == nil {
 | 
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					ss.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
 | 
						|
				} else if err != io.EOF {
 | 
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					ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
 | 
						|
					ss.trInfo.tr.SetError()
 | 
						|
				}
 | 
						|
			}
 | 
						|
			ss.mu.Unlock()
 | 
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		}
 | 
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	}()
 | 
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	return recv(ss.p, ss.codec, ss.s, ss.dc, m)
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}
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