perkeep/vendor/google.golang.org/grpc/stream.go

/*
 *
 * Copyright 2014, 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.
 *
 */

package grpc

import (
	"bytes"
	"io"
	"sync"
	"time"

	"golang.org/x/net/context"
	"golang.org/x/net/trace"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/metadata"
	"google.golang.org/grpc/stats"
	"google.golang.org/grpc/transport"
)

// StreamHandler defines the handler called by gRPC server to complete the
// execution of a streaming RPC.
type StreamHandler func(srv interface{}, stream ServerStream) error

// StreamDesc represents a streaming RPC service's method specification.
type StreamDesc struct {
	StreamName string
	Handler    StreamHandler

	// At least one of these is true.
	ServerStreams bool
	ClientStreams bool
}

// Stream defines the common interface a client or server stream has to satisfy.
type Stream interface {
	// Context returns the context for this stream.
	Context() context.Context
	// SendMsg blocks until it sends m, the stream is done or the stream
	// breaks.
	// On error, it aborts the stream and returns an RPC status on client
	// side. On server side, it simply returns the error to the caller.
	// SendMsg is called by generated code. Also Users can call SendMsg
	// directly when it is really needed in their use cases.
	SendMsg(m interface{}) error
	// RecvMsg blocks until it receives a message or the stream is
	// done. On client side, it returns io.EOF when the stream is done. On
	// any other error, it aborts the stream and returns an RPC status. On
	// server side, it simply returns the error to the caller.
	RecvMsg(m interface{}) error
}

// ClientStream defines the interface a client stream has to satisfy.
type ClientStream interface {
	// Header returns the header metadata received from the server if there
	// is any. It blocks if the metadata is not ready to read.
	Header() (metadata.MD, error)
	// Trailer returns the trailer metadata from the server, if there is any.
	// It must only be called after stream.CloseAndRecv has returned, or
	// stream.Recv has returned a non-nil error (including io.EOF).
	Trailer() metadata.MD
	// CloseSend closes the send direction of the stream. It closes the stream
	// when non-nil error is met.
	CloseSend() error
	Stream
}

// NewClientStream creates a new Stream for the client side. This is called
// by generated code.
func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
	return newClientStream(ctx, desc, cc, method, opts...)
}

func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
	var cancel context.CancelFunc

	c := defaultCallInfo
	if mc, ok := cc.getMethodConfig(method); ok {
		c.failFast = !mc.WaitForReady
		if mc.Timeout > 0 {
			ctx, cancel = context.WithTimeout(ctx, mc.Timeout)
		}
	}
	_ = cancel
	for _, o := range opts {
		if err := o.before(&c); err != nil {
			return nil, toRPCErr(err)
		}
	}
	panic("TODO(bradfitz)")
	flush := desc.ServerStreams && desc.ClientStreams
	_ = flush

	var compressAlg string
	if cc.opts.cp != nil {
		compressAlg = cc.opts.cp.Type()
	}
	_ = compressAlg
	var trInfo traceInfo
	if EnableTracing {
		trInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
		trInfo.firstLine.client = true
		if deadline, ok := ctx.Deadline(); ok {
			trInfo.firstLine.deadline = deadline.Sub(time.Now())
		}
		trInfo.tr.LazyLog(&trInfo.firstLine, false)
		ctx = trace.NewContext(ctx, trInfo.tr)
		defer func() {
			if err != nil {
				// Need to call tr.finish() if error is returned.
				// Because tr will not be returned to caller.
				trInfo.tr.LazyPrintf("RPC: [%v]", err)
				trInfo.tr.SetError()
				trInfo.tr.Finish()
			}
		}()
	}
	sh := cc.opts.statsHandler
	if sh != nil {
		ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method})
		begin := &stats.Begin{
			Client:    true,
			BeginTime: time.Now(),
			FailFast:  c.failFast,
		}
		sh.HandleRPC(ctx, begin)
	}
	defer func() {
		if err != nil && sh != nil {
			// Only handle end stats if err != nil.
			end := &stats.End{
				Client: true,
				Error:  err,
			}
			sh.HandleRPC(ctx, end)
		}
	}()
	for {
		//t, put, err = cc.getTransport(ctx)
		panic("TODO")
		if err != nil {
			// TODO(zhaoq): Probably revisit the error handling.
			if _, ok := err.(*rpcError); ok {
				return nil, err
			}
			if false { // err == errConnClosing || err == errConnUnavailable {
				if c.failFast {
					return nil, Errorf(codes.Unavailable, "%v", err)
				}
				continue
			}
			// All the other errors are treated as Internal errors.
			return nil, Errorf(codes.Internal, "%v", err)
		}

		panic("TODO")
	}
	/*
		cs := &clientStream{
			opts:   opts,
			c:      c,
			desc:   desc,
			codec:  cc.opts.codec,
			cp:     cc.opts.cp,
			dc:     cc.opts.dc,
			cancel: cancel,

			put: put,
			t:   t,
			s:   s,
			p:   &parser{r: s},

			tracing: EnableTracing,
			trInfo:  trInfo,

			statsCtx:     ctx,
			statsHandler: cc.opts.copts.StatsHandler,
		}
		if cc.opts.cp != nil {
			cs.cbuf = new(bytes.Buffer)
		}
		// Listen on ctx.Done() to detect cancellation and s.Done() to detect normal termination
		// when there is no pending I/O operations on this stream.
		go func() {
			select {
			case <-t.Error():
				// Incur transport error, simply exit.
			case <-s.Done():
				// TODO: The trace of the RPC is terminated here when there is no pending
				// I/O, which is probably not the optimal solution.
				if s.StatusCode() == codes.OK {
					cs.finish(nil)
				} else {
					cs.finish(Errorf(s.StatusCode(), "%s", s.StatusDesc()))
				}
				cs.closeTransportStream(nil)
			case <-s.GoAway():
				cs.finish(errConnDrain)
				cs.closeTransportStream(errConnDrain)
			case <-s.Context().Done():
				err := s.Context().Err()
				cs.finish(err)
				cs.closeTransportStream(transport.ContextErr(err))
			}
		}()
		return cs, nil
	*/
}

// ServerStream defines the interface a server stream has to satisfy.
type ServerStream interface {
	// SetHeader sets the header metadata. It may be called multiple times.
	// When call multiple times, all the provided metadata will be merged.
	// All the metadata will be sent out when one of the following happens:
	//  - ServerStream.SendHeader() is called;
	//  - The first response is sent out;
	//  - An RPC status is sent out (error or success).
	SetHeader(metadata.MD) error
	// SendHeader sends the header metadata.
	// The provided md and headers set by SetHeader() will be sent.
	// It fails if called multiple times.
	SendHeader(metadata.MD) error
	// SetTrailer sets the trailer metadata which will be sent with the RPC status.
	// When called more than once, all the provided metadata will be merged.
	SetTrailer(metadata.MD)
	Stream
}

// serverStream implements a server side Stream.
type serverStream struct {
	t          transport.ServerTransport
	s          *transport.Stream
	p          *parser
	codec      Codec
	cp         Compressor
	dc         Decompressor
	cbuf       *bytes.Buffer
	maxMsgSize int
	statusCode codes.Code
	statusDesc string
	trInfo     *traceInfo

	statsHandler stats.Handler

	mu sync.Mutex // protects trInfo.tr after the service handler runs.
}

func (ss *serverStream) Context() context.Context {
	return ss.s.Context()
}

func (ss *serverStream) SetHeader(md metadata.MD) error {
	if md.Len() == 0 {
		return nil
	}
	return ss.s.SetHeader(md)
}

func (ss *serverStream) SendHeader(md metadata.MD) error {
	return ss.t.WriteHeader(ss.s, md)
}

func (ss *serverStream) SetTrailer(md metadata.MD) {
	if md.Len() == 0 {
		return
	}
	ss.s.SetTrailer(md)
	return
}

func (ss *serverStream) SendMsg(m interface{}) (err error) {
	defer func() {
		if ss.trInfo != nil {
			ss.mu.Lock()
			if ss.trInfo.tr != nil {
				if err == nil {
					ss.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
				} else {
					ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
					ss.trInfo.tr.SetError()
				}
			}
			ss.mu.Unlock()
		}
	}()
	var outPayload *stats.OutPayload
	if ss.statsHandler != nil {
		outPayload = &stats.OutPayload{}
	}
	out, err := encode(ss.codec, m, ss.cp, ss.cbuf, outPayload)
	defer func() {
		if ss.cbuf != nil {
			ss.cbuf.Reset()
		}
	}()
	if err != nil {
		err = Errorf(codes.Internal, "grpc: %v", err)
		return err
	}
	if err := ss.t.Write(ss.s, out, &transport.Options{Last: false}); err != nil {
		return toRPCErr(err)
	}
	if outPayload != nil {
		outPayload.SentTime = time.Now()
		ss.statsHandler.HandleRPC(ss.s.Context(), outPayload)
	}
	return nil
}

func (ss *serverStream) RecvMsg(m interface{}) (err error) {
	defer func() {
		if ss.trInfo != nil {
			ss.mu.Lock()
			if ss.trInfo.tr != nil {
				if err == nil {
					ss.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
				} else if err != io.EOF {
					ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
					ss.trInfo.tr.SetError()
				}
			}
			ss.mu.Unlock()
		}
	}()
	var inPayload *stats.InPayload
	if ss.statsHandler != nil {
		inPayload = &stats.InPayload{}
	}
	if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxMsgSize, inPayload); err != nil {
		if err == io.EOF {
			return err
		}
		if err == io.ErrUnexpectedEOF {
			err = Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
		}
		return toRPCErr(err)
	}
	if inPayload != nil {
		ss.statsHandler.HandleRPC(ss.s.Context(), inPayload)
	}
	return nil
}