rpc_util.go

   1/*
   2 *
   3 * Copyright 2014 gRPC authors.
   4 *
   5 * Licensed under the Apache License, Version 2.0 (the "License");
   6 * you may not use this file except in compliance with the License.
   7 * You may obtain a copy of the License at
   8 *
   9 *     http://www.apache.org/licenses/LICENSE-2.0
  10 *
  11 * Unless required by applicable law or agreed to in writing, software
  12 * distributed under the License is distributed on an "AS IS" BASIS,
  13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 * See the License for the specific language governing permissions and
  15 * limitations under the License.
  16 *
  17 */
  18
  19package grpc
  20
  21import (
  22	"compress/gzip"
  23	"context"
  24	"encoding/binary"
  25	"fmt"
  26	"io"
  27	"math"
  28	"strings"
  29	"sync"
  30	"time"
  31
  32	"google.golang.org/grpc/codes"
  33	"google.golang.org/grpc/credentials"
  34	"google.golang.org/grpc/encoding"
  35	"google.golang.org/grpc/encoding/proto"
  36	"google.golang.org/grpc/internal/transport"
  37	"google.golang.org/grpc/mem"
  38	"google.golang.org/grpc/metadata"
  39	"google.golang.org/grpc/peer"
  40	"google.golang.org/grpc/stats"
  41	"google.golang.org/grpc/status"
  42)
  43
  44// Compressor defines the interface gRPC uses to compress a message.
  45//
  46// Deprecated: use package encoding.
  47type Compressor interface {
  48	// Do compresses p into w.
  49	Do(w io.Writer, p []byte) error
  50	// Type returns the compression algorithm the Compressor uses.
  51	Type() string
  52}
  53
  54type gzipCompressor struct {
  55	pool sync.Pool
  56}
  57
  58// NewGZIPCompressor creates a Compressor based on GZIP.
  59//
  60// Deprecated: use package encoding/gzip.
  61func NewGZIPCompressor() Compressor {
  62	c, _ := NewGZIPCompressorWithLevel(gzip.DefaultCompression)
  63	return c
  64}
  65
  66// NewGZIPCompressorWithLevel is like NewGZIPCompressor but specifies the gzip compression level instead
  67// of assuming DefaultCompression.
  68//
  69// The error returned will be nil if the level is valid.
  70//
  71// Deprecated: use package encoding/gzip.
  72func NewGZIPCompressorWithLevel(level int) (Compressor, error) {
  73	if level < gzip.DefaultCompression || level > gzip.BestCompression {
  74		return nil, fmt.Errorf("grpc: invalid compression level: %d", level)
  75	}
  76	return &gzipCompressor{
  77		pool: sync.Pool{
  78			New: func() any {
  79				w, err := gzip.NewWriterLevel(io.Discard, level)
  80				if err != nil {
  81					panic(err)
  82				}
  83				return w
  84			},
  85		},
  86	}, nil
  87}
  88
  89func (c *gzipCompressor) Do(w io.Writer, p []byte) error {
  90	z := c.pool.Get().(*gzip.Writer)
  91	defer c.pool.Put(z)
  92	z.Reset(w)
  93	if _, err := z.Write(p); err != nil {
  94		return err
  95	}
  96	return z.Close()
  97}
  98
  99func (c *gzipCompressor) Type() string {
 100	return "gzip"
 101}
 102
 103// Decompressor defines the interface gRPC uses to decompress a message.
 104//
 105// Deprecated: use package encoding.
 106type Decompressor interface {
 107	// Do reads the data from r and uncompress them.
 108	Do(r io.Reader) ([]byte, error)
 109	// Type returns the compression algorithm the Decompressor uses.
 110	Type() string
 111}
 112
 113type gzipDecompressor struct {
 114	pool sync.Pool
 115}
 116
 117// NewGZIPDecompressor creates a Decompressor based on GZIP.
 118//
 119// Deprecated: use package encoding/gzip.
 120func NewGZIPDecompressor() Decompressor {
 121	return &gzipDecompressor{}
 122}
 123
 124func (d *gzipDecompressor) Do(r io.Reader) ([]byte, error) {
 125	var z *gzip.Reader
 126	switch maybeZ := d.pool.Get().(type) {
 127	case nil:
 128		newZ, err := gzip.NewReader(r)
 129		if err != nil {
 130			return nil, err
 131		}
 132		z = newZ
 133	case *gzip.Reader:
 134		z = maybeZ
 135		if err := z.Reset(r); err != nil {
 136			d.pool.Put(z)
 137			return nil, err
 138		}
 139	}
 140
 141	defer func() {
 142		z.Close()
 143		d.pool.Put(z)
 144	}()
 145	return io.ReadAll(z)
 146}
 147
 148func (d *gzipDecompressor) Type() string {
 149	return "gzip"
 150}
 151
 152// callInfo contains all related configuration and information about an RPC.
 153type callInfo struct {
 154	compressorName        string
 155	failFast              bool
 156	maxReceiveMessageSize *int
 157	maxSendMessageSize    *int
 158	creds                 credentials.PerRPCCredentials
 159	contentSubtype        string
 160	codec                 baseCodec
 161	maxRetryRPCBufferSize int
 162	onFinish              []func(err error)
 163}
 164
 165func defaultCallInfo() *callInfo {
 166	return &callInfo{
 167		failFast:              true,
 168		maxRetryRPCBufferSize: 256 * 1024, // 256KB
 169	}
 170}
 171
 172// CallOption configures a Call before it starts or extracts information from
 173// a Call after it completes.
 174type CallOption interface {
 175	// before is called before the call is sent to any server.  If before
 176	// returns a non-nil error, the RPC fails with that error.
 177	before(*callInfo) error
 178
 179	// after is called after the call has completed.  after cannot return an
 180	// error, so any failures should be reported via output parameters.
 181	after(*callInfo, *csAttempt)
 182}
 183
 184// EmptyCallOption does not alter the Call configuration.
 185// It can be embedded in another structure to carry satellite data for use
 186// by interceptors.
 187type EmptyCallOption struct{}
 188
 189func (EmptyCallOption) before(*callInfo) error      { return nil }
 190func (EmptyCallOption) after(*callInfo, *csAttempt) {}
 191
 192// StaticMethod returns a CallOption which specifies that a call is being made
 193// to a method that is static, which means the method is known at compile time
 194// and doesn't change at runtime. This can be used as a signal to stats plugins
 195// that this method is safe to include as a key to a measurement.
 196func StaticMethod() CallOption {
 197	return StaticMethodCallOption{}
 198}
 199
 200// StaticMethodCallOption is a CallOption that specifies that a call comes
 201// from a static method.
 202type StaticMethodCallOption struct {
 203	EmptyCallOption
 204}
 205
 206// Header returns a CallOptions that retrieves the header metadata
 207// for a unary RPC.
 208func Header(md *metadata.MD) CallOption {
 209	return HeaderCallOption{HeaderAddr: md}
 210}
 211
 212// HeaderCallOption is a CallOption for collecting response header metadata.
 213// The metadata field will be populated *after* the RPC completes.
 214//
 215// # Experimental
 216//
 217// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 218// later release.
 219type HeaderCallOption struct {
 220	HeaderAddr *metadata.MD
 221}
 222
 223func (o HeaderCallOption) before(*callInfo) error { return nil }
 224func (o HeaderCallOption) after(_ *callInfo, attempt *csAttempt) {
 225	*o.HeaderAddr, _ = attempt.transportStream.Header()
 226}
 227
 228// Trailer returns a CallOptions that retrieves the trailer metadata
 229// for a unary RPC.
 230func Trailer(md *metadata.MD) CallOption {
 231	return TrailerCallOption{TrailerAddr: md}
 232}
 233
 234// TrailerCallOption is a CallOption for collecting response trailer metadata.
 235// The metadata field will be populated *after* the RPC completes.
 236//
 237// # Experimental
 238//
 239// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 240// later release.
 241type TrailerCallOption struct {
 242	TrailerAddr *metadata.MD
 243}
 244
 245func (o TrailerCallOption) before(*callInfo) error { return nil }
 246func (o TrailerCallOption) after(_ *callInfo, attempt *csAttempt) {
 247	*o.TrailerAddr = attempt.transportStream.Trailer()
 248}
 249
 250// Peer returns a CallOption that retrieves peer information for a unary RPC.
 251// The peer field will be populated *after* the RPC completes.
 252func Peer(p *peer.Peer) CallOption {
 253	return PeerCallOption{PeerAddr: p}
 254}
 255
 256// PeerCallOption is a CallOption for collecting the identity of the remote
 257// peer. The peer field will be populated *after* the RPC completes.
 258//
 259// # Experimental
 260//
 261// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 262// later release.
 263type PeerCallOption struct {
 264	PeerAddr *peer.Peer
 265}
 266
 267func (o PeerCallOption) before(*callInfo) error { return nil }
 268func (o PeerCallOption) after(_ *callInfo, attempt *csAttempt) {
 269	if x, ok := peer.FromContext(attempt.transportStream.Context()); ok {
 270		*o.PeerAddr = *x
 271	}
 272}
 273
 274// WaitForReady configures the RPC's behavior when the client is in
 275// TRANSIENT_FAILURE, which occurs when all addresses fail to connect.  If
 276// waitForReady is false, the RPC will fail immediately.  Otherwise, the client
 277// will wait until a connection becomes available or the RPC's deadline is
 278// reached.
 279//
 280// By default, RPCs do not "wait for ready".
 281func WaitForReady(waitForReady bool) CallOption {
 282	return FailFastCallOption{FailFast: !waitForReady}
 283}
 284
 285// FailFast is the opposite of WaitForReady.
 286//
 287// Deprecated: use WaitForReady.
 288func FailFast(failFast bool) CallOption {
 289	return FailFastCallOption{FailFast: failFast}
 290}
 291
 292// FailFastCallOption is a CallOption for indicating whether an RPC should fail
 293// fast or not.
 294//
 295// # Experimental
 296//
 297// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 298// later release.
 299type FailFastCallOption struct {
 300	FailFast bool
 301}
 302
 303func (o FailFastCallOption) before(c *callInfo) error {
 304	c.failFast = o.FailFast
 305	return nil
 306}
 307func (o FailFastCallOption) after(*callInfo, *csAttempt) {}
 308
 309// OnFinish returns a CallOption that configures a callback to be called when
 310// the call completes. The error passed to the callback is the status of the
 311// RPC, and may be nil. The onFinish callback provided will only be called once
 312// by gRPC. This is mainly used to be used by streaming interceptors, to be
 313// notified when the RPC completes along with information about the status of
 314// the RPC.
 315//
 316// # Experimental
 317//
 318// Notice: This API is EXPERIMENTAL and may be changed or removed in a
 319// later release.
 320func OnFinish(onFinish func(err error)) CallOption {
 321	return OnFinishCallOption{
 322		OnFinish: onFinish,
 323	}
 324}
 325
 326// OnFinishCallOption is CallOption that indicates a callback to be called when
 327// the call completes.
 328//
 329// # Experimental
 330//
 331// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 332// later release.
 333type OnFinishCallOption struct {
 334	OnFinish func(error)
 335}
 336
 337func (o OnFinishCallOption) before(c *callInfo) error {
 338	c.onFinish = append(c.onFinish, o.OnFinish)
 339	return nil
 340}
 341
 342func (o OnFinishCallOption) after(*callInfo, *csAttempt) {}
 343
 344// MaxCallRecvMsgSize returns a CallOption which sets the maximum message size
 345// in bytes the client can receive. If this is not set, gRPC uses the default
 346// 4MB.
 347func MaxCallRecvMsgSize(bytes int) CallOption {
 348	return MaxRecvMsgSizeCallOption{MaxRecvMsgSize: bytes}
 349}
 350
 351// MaxRecvMsgSizeCallOption is a CallOption that indicates the maximum message
 352// size in bytes the client can receive.
 353//
 354// # Experimental
 355//
 356// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 357// later release.
 358type MaxRecvMsgSizeCallOption struct {
 359	MaxRecvMsgSize int
 360}
 361
 362func (o MaxRecvMsgSizeCallOption) before(c *callInfo) error {
 363	c.maxReceiveMessageSize = &o.MaxRecvMsgSize
 364	return nil
 365}
 366func (o MaxRecvMsgSizeCallOption) after(*callInfo, *csAttempt) {}
 367
 368// MaxCallSendMsgSize returns a CallOption which sets the maximum message size
 369// in bytes the client can send. If this is not set, gRPC uses the default
 370// `math.MaxInt32`.
 371func MaxCallSendMsgSize(bytes int) CallOption {
 372	return MaxSendMsgSizeCallOption{MaxSendMsgSize: bytes}
 373}
 374
 375// MaxSendMsgSizeCallOption is a CallOption that indicates the maximum message
 376// size in bytes the client can send.
 377//
 378// # Experimental
 379//
 380// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 381// later release.
 382type MaxSendMsgSizeCallOption struct {
 383	MaxSendMsgSize int
 384}
 385
 386func (o MaxSendMsgSizeCallOption) before(c *callInfo) error {
 387	c.maxSendMessageSize = &o.MaxSendMsgSize
 388	return nil
 389}
 390func (o MaxSendMsgSizeCallOption) after(*callInfo, *csAttempt) {}
 391
 392// PerRPCCredentials returns a CallOption that sets credentials.PerRPCCredentials
 393// for a call.
 394func PerRPCCredentials(creds credentials.PerRPCCredentials) CallOption {
 395	return PerRPCCredsCallOption{Creds: creds}
 396}
 397
 398// PerRPCCredsCallOption is a CallOption that indicates the per-RPC
 399// credentials to use for the call.
 400//
 401// # Experimental
 402//
 403// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 404// later release.
 405type PerRPCCredsCallOption struct {
 406	Creds credentials.PerRPCCredentials
 407}
 408
 409func (o PerRPCCredsCallOption) before(c *callInfo) error {
 410	c.creds = o.Creds
 411	return nil
 412}
 413func (o PerRPCCredsCallOption) after(*callInfo, *csAttempt) {}
 414
 415// UseCompressor returns a CallOption which sets the compressor used when
 416// sending the request.  If WithCompressor is also set, UseCompressor has
 417// higher priority.
 418//
 419// # Experimental
 420//
 421// Notice: This API is EXPERIMENTAL and may be changed or removed in a
 422// later release.
 423func UseCompressor(name string) CallOption {
 424	return CompressorCallOption{CompressorType: name}
 425}
 426
 427// CompressorCallOption is a CallOption that indicates the compressor to use.
 428//
 429// # Experimental
 430//
 431// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 432// later release.
 433type CompressorCallOption struct {
 434	CompressorType string
 435}
 436
 437func (o CompressorCallOption) before(c *callInfo) error {
 438	c.compressorName = o.CompressorType
 439	return nil
 440}
 441func (o CompressorCallOption) after(*callInfo, *csAttempt) {}
 442
 443// CallContentSubtype returns a CallOption that will set the content-subtype
 444// for a call. For example, if content-subtype is "json", the Content-Type over
 445// the wire will be "application/grpc+json". The content-subtype is converted
 446// to lowercase before being included in Content-Type. See Content-Type on
 447// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
 448// more details.
 449//
 450// If ForceCodec is not also used, the content-subtype will be used to look up
 451// the Codec to use in the registry controlled by RegisterCodec. See the
 452// documentation on RegisterCodec for details on registration. The lookup of
 453// content-subtype is case-insensitive. If no such Codec is found, the call
 454// will result in an error with code codes.Internal.
 455//
 456// If ForceCodec is also used, that Codec will be used for all request and
 457// response messages, with the content-subtype set to the given contentSubtype
 458// here for requests.
 459func CallContentSubtype(contentSubtype string) CallOption {
 460	return ContentSubtypeCallOption{ContentSubtype: strings.ToLower(contentSubtype)}
 461}
 462
 463// ContentSubtypeCallOption is a CallOption that indicates the content-subtype
 464// used for marshaling messages.
 465//
 466// # Experimental
 467//
 468// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 469// later release.
 470type ContentSubtypeCallOption struct {
 471	ContentSubtype string
 472}
 473
 474func (o ContentSubtypeCallOption) before(c *callInfo) error {
 475	c.contentSubtype = o.ContentSubtype
 476	return nil
 477}
 478func (o ContentSubtypeCallOption) after(*callInfo, *csAttempt) {}
 479
 480// ForceCodec returns a CallOption that will set codec to be used for all
 481// request and response messages for a call. The result of calling Name() will
 482// be used as the content-subtype after converting to lowercase, unless
 483// CallContentSubtype is also used.
 484//
 485// See Content-Type on
 486// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
 487// more details. Also see the documentation on RegisterCodec and
 488// CallContentSubtype for more details on the interaction between Codec and
 489// content-subtype.
 490//
 491// This function is provided for advanced users; prefer to use only
 492// CallContentSubtype to select a registered codec instead.
 493//
 494// # Experimental
 495//
 496// Notice: This API is EXPERIMENTAL and may be changed or removed in a
 497// later release.
 498func ForceCodec(codec encoding.Codec) CallOption {
 499	return ForceCodecCallOption{Codec: codec}
 500}
 501
 502// ForceCodecCallOption is a CallOption that indicates the codec used for
 503// marshaling messages.
 504//
 505// # Experimental
 506//
 507// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 508// later release.
 509type ForceCodecCallOption struct {
 510	Codec encoding.Codec
 511}
 512
 513func (o ForceCodecCallOption) before(c *callInfo) error {
 514	c.codec = newCodecV1Bridge(o.Codec)
 515	return nil
 516}
 517func (o ForceCodecCallOption) after(*callInfo, *csAttempt) {}
 518
 519// ForceCodecV2 returns a CallOption that will set codec to be used for all
 520// request and response messages for a call. The result of calling Name() will
 521// be used as the content-subtype after converting to lowercase, unless
 522// CallContentSubtype is also used.
 523//
 524// See Content-Type on
 525// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
 526// more details. Also see the documentation on RegisterCodec and
 527// CallContentSubtype for more details on the interaction between Codec and
 528// content-subtype.
 529//
 530// This function is provided for advanced users; prefer to use only
 531// CallContentSubtype to select a registered codec instead.
 532//
 533// # Experimental
 534//
 535// Notice: This API is EXPERIMENTAL and may be changed or removed in a
 536// later release.
 537func ForceCodecV2(codec encoding.CodecV2) CallOption {
 538	return ForceCodecV2CallOption{CodecV2: codec}
 539}
 540
 541// ForceCodecV2CallOption is a CallOption that indicates the codec used for
 542// marshaling messages.
 543//
 544// # Experimental
 545//
 546// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 547// later release.
 548type ForceCodecV2CallOption struct {
 549	CodecV2 encoding.CodecV2
 550}
 551
 552func (o ForceCodecV2CallOption) before(c *callInfo) error {
 553	c.codec = o.CodecV2
 554	return nil
 555}
 556
 557func (o ForceCodecV2CallOption) after(*callInfo, *csAttempt) {}
 558
 559// CallCustomCodec behaves like ForceCodec, but accepts a grpc.Codec instead of
 560// an encoding.Codec.
 561//
 562// Deprecated: use ForceCodec instead.
 563func CallCustomCodec(codec Codec) CallOption {
 564	return CustomCodecCallOption{Codec: codec}
 565}
 566
 567// CustomCodecCallOption is a CallOption that indicates the codec used for
 568// marshaling messages.
 569//
 570// # Experimental
 571//
 572// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 573// later release.
 574type CustomCodecCallOption struct {
 575	Codec Codec
 576}
 577
 578func (o CustomCodecCallOption) before(c *callInfo) error {
 579	c.codec = newCodecV0Bridge(o.Codec)
 580	return nil
 581}
 582func (o CustomCodecCallOption) after(*callInfo, *csAttempt) {}
 583
 584// MaxRetryRPCBufferSize returns a CallOption that limits the amount of memory
 585// used for buffering this RPC's requests for retry purposes.
 586//
 587// # Experimental
 588//
 589// Notice: This API is EXPERIMENTAL and may be changed or removed in a
 590// later release.
 591func MaxRetryRPCBufferSize(bytes int) CallOption {
 592	return MaxRetryRPCBufferSizeCallOption{bytes}
 593}
 594
 595// MaxRetryRPCBufferSizeCallOption is a CallOption indicating the amount of
 596// memory to be used for caching this RPC for retry purposes.
 597//
 598// # Experimental
 599//
 600// Notice: This type is EXPERIMENTAL and may be changed or removed in a
 601// later release.
 602type MaxRetryRPCBufferSizeCallOption struct {
 603	MaxRetryRPCBufferSize int
 604}
 605
 606func (o MaxRetryRPCBufferSizeCallOption) before(c *callInfo) error {
 607	c.maxRetryRPCBufferSize = o.MaxRetryRPCBufferSize
 608	return nil
 609}
 610func (o MaxRetryRPCBufferSizeCallOption) after(*callInfo, *csAttempt) {}
 611
 612// The format of the payload: compressed or not?
 613type payloadFormat uint8
 614
 615const (
 616	compressionNone payloadFormat = 0 // no compression
 617	compressionMade payloadFormat = 1 // compressed
 618)
 619
 620func (pf payloadFormat) isCompressed() bool {
 621	return pf == compressionMade
 622}
 623
 624type streamReader interface {
 625	ReadMessageHeader(header []byte) error
 626	Read(n int) (mem.BufferSlice, error)
 627}
 628
 629// parser reads complete gRPC messages from the underlying reader.
 630type parser struct {
 631	// r is the underlying reader.
 632	// See the comment on recvMsg for the permissible
 633	// error types.
 634	r streamReader
 635
 636	// The header of a gRPC message. Find more detail at
 637	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md
 638	header [5]byte
 639
 640	// bufferPool is the pool of shared receive buffers.
 641	bufferPool mem.BufferPool
 642}
 643
 644// recvMsg reads a complete gRPC message from the stream.
 645//
 646// It returns the message and its payload (compression/encoding)
 647// format. The caller owns the returned msg memory.
 648//
 649// If there is an error, possible values are:
 650//   - io.EOF, when no messages remain
 651//   - io.ErrUnexpectedEOF
 652//   - of type transport.ConnectionError
 653//   - an error from the status package
 654//
 655// No other error values or types must be returned, which also means
 656// that the underlying streamReader must not return an incompatible
 657// error.
 658func (p *parser) recvMsg(maxReceiveMessageSize int) (payloadFormat, mem.BufferSlice, error) {
 659	err := p.r.ReadMessageHeader(p.header[:])
 660	if err != nil {
 661		return 0, nil, err
 662	}
 663
 664	pf := payloadFormat(p.header[0])
 665	length := binary.BigEndian.Uint32(p.header[1:])
 666
 667	if int64(length) > int64(maxInt) {
 668		return 0, nil, status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max length allowed on current machine (%d vs. %d)", length, maxInt)
 669	}
 670	if int(length) > maxReceiveMessageSize {
 671		return 0, nil, status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", length, maxReceiveMessageSize)
 672	}
 673
 674	data, err := p.r.Read(int(length))
 675	if err != nil {
 676		if err == io.EOF {
 677			err = io.ErrUnexpectedEOF
 678		}
 679		return 0, nil, err
 680	}
 681	return pf, data, nil
 682}
 683
 684// encode serializes msg and returns a buffer containing the message, or an
 685// error if it is too large to be transmitted by grpc.  If msg is nil, it
 686// generates an empty message.
 687func encode(c baseCodec, msg any) (mem.BufferSlice, error) {
 688	if msg == nil { // NOTE: typed nils will not be caught by this check
 689		return nil, nil
 690	}
 691	b, err := c.Marshal(msg)
 692	if err != nil {
 693		return nil, status.Errorf(codes.Internal, "grpc: error while marshaling: %v", err.Error())
 694	}
 695	if bufSize := uint(b.Len()); bufSize > math.MaxUint32 {
 696		b.Free()
 697		return nil, status.Errorf(codes.ResourceExhausted, "grpc: message too large (%d bytes)", bufSize)
 698	}
 699	return b, nil
 700}
 701
 702// compress returns the input bytes compressed by compressor or cp.
 703// If both compressors are nil, or if the message has zero length, returns nil,
 704// indicating no compression was done.
 705//
 706// TODO(dfawley): eliminate cp parameter by wrapping Compressor in an encoding.Compressor.
 707func compress(in mem.BufferSlice, cp Compressor, compressor encoding.Compressor, pool mem.BufferPool) (mem.BufferSlice, payloadFormat, error) {
 708	if (compressor == nil && cp == nil) || in.Len() == 0 {
 709		return nil, compressionNone, nil
 710	}
 711	var out mem.BufferSlice
 712	w := mem.NewWriter(&out, pool)
 713	wrapErr := func(err error) error {
 714		out.Free()
 715		return status.Errorf(codes.Internal, "grpc: error while compressing: %v", err.Error())
 716	}
 717	if compressor != nil {
 718		z, err := compressor.Compress(w)
 719		if err != nil {
 720			return nil, 0, wrapErr(err)
 721		}
 722		for _, b := range in {
 723			if _, err := z.Write(b.ReadOnlyData()); err != nil {
 724				return nil, 0, wrapErr(err)
 725			}
 726		}
 727		if err := z.Close(); err != nil {
 728			return nil, 0, wrapErr(err)
 729		}
 730	} else {
 731		// This is obviously really inefficient since it fully materializes the data, but
 732		// there is no way around this with the old Compressor API. At least it attempts
 733		// to return the buffer to the provider, in the hopes it can be reused (maybe
 734		// even by a subsequent call to this very function).
 735		buf := in.MaterializeToBuffer(pool)
 736		defer buf.Free()
 737		if err := cp.Do(w, buf.ReadOnlyData()); err != nil {
 738			return nil, 0, wrapErr(err)
 739		}
 740	}
 741	return out, compressionMade, nil
 742}
 743
 744const (
 745	payloadLen = 1
 746	sizeLen    = 4
 747	headerLen  = payloadLen + sizeLen
 748)
 749
 750// msgHeader returns a 5-byte header for the message being transmitted and the
 751// payload, which is compData if non-nil or data otherwise.
 752func msgHeader(data, compData mem.BufferSlice, pf payloadFormat) (hdr []byte, payload mem.BufferSlice) {
 753	hdr = make([]byte, headerLen)
 754	hdr[0] = byte(pf)
 755
 756	var length uint32
 757	if pf.isCompressed() {
 758		length = uint32(compData.Len())
 759		payload = compData
 760	} else {
 761		length = uint32(data.Len())
 762		payload = data
 763	}
 764
 765	// Write length of payload into buf
 766	binary.BigEndian.PutUint32(hdr[payloadLen:], length)
 767	return hdr, payload
 768}
 769
 770func outPayload(client bool, msg any, dataLength, payloadLength int, t time.Time) *stats.OutPayload {
 771	return &stats.OutPayload{
 772		Client:           client,
 773		Payload:          msg,
 774		Length:           dataLength,
 775		WireLength:       payloadLength + headerLen,
 776		CompressedLength: payloadLength,
 777		SentTime:         t,
 778	}
 779}
 780
 781func checkRecvPayload(pf payloadFormat, recvCompress string, haveCompressor bool, isServer bool) *status.Status {
 782	switch pf {
 783	case compressionNone:
 784	case compressionMade:
 785		if recvCompress == "" || recvCompress == encoding.Identity {
 786			return status.New(codes.Internal, "grpc: compressed flag set with identity or empty encoding")
 787		}
 788		if !haveCompressor {
 789			if isServer {
 790				return status.Newf(codes.Unimplemented, "grpc: Decompressor is not installed for grpc-encoding %q", recvCompress)
 791			}
 792			return status.Newf(codes.Internal, "grpc: Decompressor is not installed for grpc-encoding %q", recvCompress)
 793		}
 794	default:
 795		return status.Newf(codes.Internal, "grpc: received unexpected payload format %d", pf)
 796	}
 797	return nil
 798}
 799
 800type payloadInfo struct {
 801	compressedLength  int // The compressed length got from wire.
 802	uncompressedBytes mem.BufferSlice
 803}
 804
 805func (p *payloadInfo) free() {
 806	if p != nil && p.uncompressedBytes != nil {
 807		p.uncompressedBytes.Free()
 808	}
 809}
 810
 811// recvAndDecompress reads a message from the stream, decompressing it if necessary.
 812//
 813// Cancelling the returned cancel function releases the buffer back to the pool. So the caller should cancel as soon as
 814// the buffer is no longer needed.
 815// TODO: Refactor this function to reduce the number of arguments.
 816// See: https://google.github.io/styleguide/go/best-practices.html#function-argument-lists
 817func recvAndDecompress(p *parser, s recvCompressor, dc Decompressor, maxReceiveMessageSize int, payInfo *payloadInfo, compressor encoding.Compressor, isServer bool,
 818) (out mem.BufferSlice, err error) {
 819	pf, compressed, err := p.recvMsg(maxReceiveMessageSize)
 820	if err != nil {
 821		return nil, err
 822	}
 823
 824	compressedLength := compressed.Len()
 825
 826	if st := checkRecvPayload(pf, s.RecvCompress(), compressor != nil || dc != nil, isServer); st != nil {
 827		compressed.Free()
 828		return nil, st.Err()
 829	}
 830
 831	if pf.isCompressed() {
 832		defer compressed.Free()
 833		// To match legacy behavior, if the decompressor is set by WithDecompressor or RPCDecompressor,
 834		// use this decompressor as the default.
 835		out, err = decompress(compressor, compressed, dc, maxReceiveMessageSize, p.bufferPool)
 836		if err != nil {
 837			return nil, err
 838		}
 839	} else {
 840		out = compressed
 841	}
 842
 843	if payInfo != nil {
 844		payInfo.compressedLength = compressedLength
 845		out.Ref()
 846		payInfo.uncompressedBytes = out
 847	}
 848
 849	return out, nil
 850}
 851
 852// decompress processes the given data by decompressing it using either a custom decompressor or a standard compressor.
 853// If a custom decompressor is provided, it takes precedence. The function validates that the decompressed data
 854// does not exceed the specified maximum size and returns an error if this limit is exceeded.
 855// On success, it returns the decompressed data. Otherwise, it returns an error if decompression fails or the data exceeds the size limit.
 856func decompress(compressor encoding.Compressor, d mem.BufferSlice, dc Decompressor, maxReceiveMessageSize int, pool mem.BufferPool) (mem.BufferSlice, error) {
 857	if dc != nil {
 858		uncompressed, err := dc.Do(d.Reader())
 859		if err != nil {
 860			return nil, status.Errorf(codes.Internal, "grpc: failed to decompress the received message: %v", err)
 861		}
 862		if len(uncompressed) > maxReceiveMessageSize {
 863			return nil, status.Errorf(codes.ResourceExhausted, "grpc: message after decompression larger than max (%d vs. %d)", len(uncompressed), maxReceiveMessageSize)
 864		}
 865		return mem.BufferSlice{mem.SliceBuffer(uncompressed)}, nil
 866	}
 867	if compressor != nil {
 868		dcReader, err := compressor.Decompress(d.Reader())
 869		if err != nil {
 870			return nil, status.Errorf(codes.Internal, "grpc: failed to decompress the message: %v", err)
 871		}
 872
 873		out, err := mem.ReadAll(io.LimitReader(dcReader, int64(maxReceiveMessageSize)), pool)
 874		if err != nil {
 875			out.Free()
 876			return nil, status.Errorf(codes.Internal, "grpc: failed to read decompressed data: %v", err)
 877		}
 878
 879		if out.Len() == maxReceiveMessageSize && !atEOF(dcReader) {
 880			out.Free()
 881			return nil, status.Errorf(codes.ResourceExhausted, "grpc: received message after decompression larger than max %d", maxReceiveMessageSize)
 882		}
 883		return out, nil
 884	}
 885	return nil, status.Errorf(codes.Internal, "grpc: no decompressor available for compressed payload")
 886}
 887
 888// atEOF reads data from r and returns true if zero bytes could be read and r.Read returns EOF.
 889func atEOF(dcReader io.Reader) bool {
 890	n, err := dcReader.Read(make([]byte, 1))
 891	return n == 0 && err == io.EOF
 892}
 893
 894type recvCompressor interface {
 895	RecvCompress() string
 896}
 897
 898// For the two compressor parameters, both should not be set, but if they are,
 899// dc takes precedence over compressor.
 900// TODO(dfawley): wrap the old compressor/decompressor using the new API?
 901func recv(p *parser, c baseCodec, s recvCompressor, dc Decompressor, m any, maxReceiveMessageSize int, payInfo *payloadInfo, compressor encoding.Compressor, isServer bool) error {
 902	data, err := recvAndDecompress(p, s, dc, maxReceiveMessageSize, payInfo, compressor, isServer)
 903	if err != nil {
 904		return err
 905	}
 906
 907	// If the codec wants its own reference to the data, it can get it. Otherwise, always
 908	// free the buffers.
 909	defer data.Free()
 910
 911	if err := c.Unmarshal(data, m); err != nil {
 912		return status.Errorf(codes.Internal, "grpc: failed to unmarshal the received message: %v", err)
 913	}
 914
 915	return nil
 916}
 917
 918// Information about RPC
 919type rpcInfo struct {
 920	failfast      bool
 921	preloaderInfo *compressorInfo
 922}
 923
 924// Information about Preloader
 925// Responsible for storing codec, and compressors
 926// If stream (s) has  context s.Context which stores rpcInfo that has non nil
 927// pointers to codec, and compressors, then we can use preparedMsg for Async message prep
 928// and reuse marshalled bytes
 929type compressorInfo struct {
 930	codec baseCodec
 931	cp    Compressor
 932	comp  encoding.Compressor
 933}
 934
 935type rpcInfoContextKey struct{}
 936
 937func newContextWithRPCInfo(ctx context.Context, failfast bool, codec baseCodec, cp Compressor, comp encoding.Compressor) context.Context {
 938	return context.WithValue(ctx, rpcInfoContextKey{}, &rpcInfo{
 939		failfast: failfast,
 940		preloaderInfo: &compressorInfo{
 941			codec: codec,
 942			cp:    cp,
 943			comp:  comp,
 944		},
 945	})
 946}
 947
 948func rpcInfoFromContext(ctx context.Context) (s *rpcInfo, ok bool) {
 949	s, ok = ctx.Value(rpcInfoContextKey{}).(*rpcInfo)
 950	return
 951}
 952
 953// Code returns the error code for err if it was produced by the rpc system.
 954// Otherwise, it returns codes.Unknown.
 955//
 956// Deprecated: use status.Code instead.
 957func Code(err error) codes.Code {
 958	return status.Code(err)
 959}
 960
 961// ErrorDesc returns the error description of err if it was produced by the rpc system.
 962// Otherwise, it returns err.Error() or empty string when err is nil.
 963//
 964// Deprecated: use status.Convert and Message method instead.
 965func ErrorDesc(err error) string {
 966	return status.Convert(err).Message()
 967}
 968
 969// Errorf returns an error containing an error code and a description;
 970// Errorf returns nil if c is OK.
 971//
 972// Deprecated: use status.Errorf instead.
 973func Errorf(c codes.Code, format string, a ...any) error {
 974	return status.Errorf(c, format, a...)
 975}
 976
 977var errContextCanceled = status.Error(codes.Canceled, context.Canceled.Error())
 978var errContextDeadline = status.Error(codes.DeadlineExceeded, context.DeadlineExceeded.Error())
 979
 980// toRPCErr converts an error into an error from the status package.
 981func toRPCErr(err error) error {
 982	switch err {
 983	case nil, io.EOF:
 984		return err
 985	case context.DeadlineExceeded:
 986		return errContextDeadline
 987	case context.Canceled:
 988		return errContextCanceled
 989	case io.ErrUnexpectedEOF:
 990		return status.Error(codes.Internal, err.Error())
 991	}
 992
 993	switch e := err.(type) {
 994	case transport.ConnectionError:
 995		return status.Error(codes.Unavailable, e.Desc)
 996	case *transport.NewStreamError:
 997		return toRPCErr(e.Err)
 998	}
 999
1000	if _, ok := status.FromError(err); ok {
1001		return err
1002	}
1003
1004	return status.Error(codes.Unknown, err.Error())
1005}
1006
1007// setCallInfoCodec should only be called after CallOptions have been applied.
1008func setCallInfoCodec(c *callInfo) error {
1009	if c.codec != nil {
1010		// codec was already set by a CallOption; use it, but set the content
1011		// subtype if it is not set.
1012		if c.contentSubtype == "" {
1013			// c.codec is a baseCodec to hide the difference between grpc.Codec and
1014			// encoding.Codec (Name vs. String method name).  We only support
1015			// setting content subtype from encoding.Codec to avoid a behavior
1016			// change with the deprecated version.
1017			if ec, ok := c.codec.(encoding.CodecV2); ok {
1018				c.contentSubtype = strings.ToLower(ec.Name())
1019			}
1020		}
1021		return nil
1022	}
1023
1024	if c.contentSubtype == "" {
1025		// No codec specified in CallOptions; use proto by default.
1026		c.codec = getCodec(proto.Name)
1027		return nil
1028	}
1029
1030	// c.contentSubtype is already lowercased in CallContentSubtype
1031	c.codec = getCodec(c.contentSubtype)
1032	if c.codec == nil {
1033		return status.Errorf(codes.Internal, "no codec registered for content-subtype %s", c.contentSubtype)
1034	}
1035	return nil
1036}
1037
1038// The SupportPackageIsVersion variables are referenced from generated protocol
1039// buffer files to ensure compatibility with the gRPC version used.  The latest
1040// support package version is 9.
1041//
1042// Older versions are kept for compatibility.
1043//
1044// These constants should not be referenced from any other code.
1045const (
1046	SupportPackageIsVersion3 = true
1047	SupportPackageIsVersion4 = true
1048	SupportPackageIsVersion5 = true
1049	SupportPackageIsVersion6 = true
1050	SupportPackageIsVersion7 = true
1051	SupportPackageIsVersion8 = true
1052	SupportPackageIsVersion9 = true
1053)
1054
1055const grpcUA = "grpc-go/" + Version