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author | Wim <wim@42.be> | 2020-08-10 00:29:54 +0200 |
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committer | GitHub <noreply@github.com> | 2020-08-10 00:29:54 +0200 |
commit | 4e50fd864921c556988c919269448efdb90fa961 (patch) | |
tree | a3625f03f8de3c4f3841364000a4ea3aa42c1533 /vendor/google.golang.org/protobuf/internal/encoding/messageset | |
parent | dfdffa0027334e55ce213fc6eb62206dbf48baf6 (diff) | |
download | matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.tar.gz matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.tar.bz2 matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.zip |
Use mattermost v5 module (#1192)
Diffstat (limited to 'vendor/google.golang.org/protobuf/internal/encoding/messageset')
-rw-r--r-- | vendor/google.golang.org/protobuf/internal/encoding/messageset/messageset.go | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/vendor/google.golang.org/protobuf/internal/encoding/messageset/messageset.go b/vendor/google.golang.org/protobuf/internal/encoding/messageset/messageset.go new file mode 100644 index 00000000..b1eeea50 --- /dev/null +++ b/vendor/google.golang.org/protobuf/internal/encoding/messageset/messageset.go @@ -0,0 +1,258 @@ +// Copyright 2019 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package messageset encodes and decodes the obsolete MessageSet wire format. +package messageset + +import ( + "math" + + "google.golang.org/protobuf/encoding/protowire" + "google.golang.org/protobuf/internal/errors" + pref "google.golang.org/protobuf/reflect/protoreflect" + preg "google.golang.org/protobuf/reflect/protoregistry" +) + +// The MessageSet wire format is equivalent to a message defiend as follows, +// where each Item defines an extension field with a field number of 'type_id' +// and content of 'message'. MessageSet extensions must be non-repeated message +// fields. +// +// message MessageSet { +// repeated group Item = 1 { +// required int32 type_id = 2; +// required string message = 3; +// } +// } +const ( + FieldItem = protowire.Number(1) + FieldTypeID = protowire.Number(2) + FieldMessage = protowire.Number(3) +) + +// ExtensionName is the field name for extensions of MessageSet. +// +// A valid MessageSet extension must be of the form: +// message MyMessage { +// extend proto2.bridge.MessageSet { +// optional MyMessage message_set_extension = 1234; +// } +// ... +// } +const ExtensionName = "message_set_extension" + +// IsMessageSet returns whether the message uses the MessageSet wire format. +func IsMessageSet(md pref.MessageDescriptor) bool { + xmd, ok := md.(interface{ IsMessageSet() bool }) + return ok && xmd.IsMessageSet() +} + +// IsMessageSetExtension reports this field extends a MessageSet. +func IsMessageSetExtension(fd pref.FieldDescriptor) bool { + if fd.Name() != ExtensionName { + return false + } + if fd.FullName().Parent() != fd.Message().FullName() { + return false + } + return IsMessageSet(fd.ContainingMessage()) +} + +// FindMessageSetExtension locates a MessageSet extension field by name. +// In text and JSON formats, the extension name used is the message itself. +// The extension field name is derived by appending ExtensionName. +func FindMessageSetExtension(r preg.ExtensionTypeResolver, s pref.FullName) (pref.ExtensionType, error) { + name := s.Append(ExtensionName) + xt, err := r.FindExtensionByName(name) + if err != nil { + if err == preg.NotFound { + return nil, err + } + return nil, errors.Wrap(err, "%q", name) + } + if !IsMessageSetExtension(xt.TypeDescriptor()) { + return nil, preg.NotFound + } + return xt, nil +} + +// SizeField returns the size of a MessageSet item field containing an extension +// with the given field number, not counting the contents of the message subfield. +func SizeField(num protowire.Number) int { + return 2*protowire.SizeTag(FieldItem) + protowire.SizeTag(FieldTypeID) + protowire.SizeVarint(uint64(num)) +} + +// Unmarshal parses a MessageSet. +// +// It calls fn with the type ID and value of each item in the MessageSet. +// Unknown fields are discarded. +// +// If wantLen is true, the item values include the varint length prefix. +// This is ugly, but simplifies the fast-path decoder in internal/impl. +func Unmarshal(b []byte, wantLen bool, fn func(typeID protowire.Number, value []byte) error) error { + for len(b) > 0 { + num, wtyp, n := protowire.ConsumeTag(b) + if n < 0 { + return protowire.ParseError(n) + } + b = b[n:] + if num != FieldItem || wtyp != protowire.StartGroupType { + n := protowire.ConsumeFieldValue(num, wtyp, b) + if n < 0 { + return protowire.ParseError(n) + } + b = b[n:] + continue + } + typeID, value, n, err := ConsumeFieldValue(b, wantLen) + if err != nil { + return err + } + b = b[n:] + if typeID == 0 { + continue + } + if err := fn(typeID, value); err != nil { + return err + } + } + return nil +} + +// ConsumeFieldValue parses b as a MessageSet item field value until and including +// the trailing end group marker. It assumes the start group tag has already been parsed. +// It returns the contents of the type_id and message subfields and the total +// item length. +// +// If wantLen is true, the returned message value includes the length prefix. +func ConsumeFieldValue(b []byte, wantLen bool) (typeid protowire.Number, message []byte, n int, err error) { + ilen := len(b) + for { + num, wtyp, n := protowire.ConsumeTag(b) + if n < 0 { + return 0, nil, 0, protowire.ParseError(n) + } + b = b[n:] + switch { + case num == FieldItem && wtyp == protowire.EndGroupType: + if wantLen && len(message) == 0 { + // The message field was missing, which should never happen. + // Be prepared for this case anyway. + message = protowire.AppendVarint(message, 0) + } + return typeid, message, ilen - len(b), nil + case num == FieldTypeID && wtyp == protowire.VarintType: + v, n := protowire.ConsumeVarint(b) + if n < 0 { + return 0, nil, 0, protowire.ParseError(n) + } + b = b[n:] + if v < 1 || v > math.MaxInt32 { + return 0, nil, 0, errors.New("invalid type_id in message set") + } + typeid = protowire.Number(v) + case num == FieldMessage && wtyp == protowire.BytesType: + m, n := protowire.ConsumeBytes(b) + if n < 0 { + return 0, nil, 0, protowire.ParseError(n) + } + if message == nil { + if wantLen { + message = b[:n:n] + } else { + message = m[:len(m):len(m)] + } + } else { + // This case should never happen in practice, but handle it for + // correctness: The MessageSet item contains multiple message + // fields, which need to be merged. + // + // In the case where we're returning the length, this becomes + // quite inefficient since we need to strip the length off + // the existing data and reconstruct it with the combined length. + if wantLen { + _, nn := protowire.ConsumeVarint(message) + m0 := message[nn:] + message = nil + message = protowire.AppendVarint(message, uint64(len(m0)+len(m))) + message = append(message, m0...) + message = append(message, m...) + } else { + message = append(message, m...) + } + } + b = b[n:] + default: + // We have no place to put it, so we just ignore unknown fields. + n := protowire.ConsumeFieldValue(num, wtyp, b) + if n < 0 { + return 0, nil, 0, protowire.ParseError(n) + } + b = b[n:] + } + } +} + +// AppendFieldStart appends the start of a MessageSet item field containing +// an extension with the given number. The caller must add the message +// subfield (including the tag). +func AppendFieldStart(b []byte, num protowire.Number) []byte { + b = protowire.AppendTag(b, FieldItem, protowire.StartGroupType) + b = protowire.AppendTag(b, FieldTypeID, protowire.VarintType) + b = protowire.AppendVarint(b, uint64(num)) + return b +} + +// AppendFieldEnd appends the trailing end group marker for a MessageSet item field. +func AppendFieldEnd(b []byte) []byte { + return protowire.AppendTag(b, FieldItem, protowire.EndGroupType) +} + +// SizeUnknown returns the size of an unknown fields section in MessageSet format. +// +// See AppendUnknown. +func SizeUnknown(unknown []byte) (size int) { + for len(unknown) > 0 { + num, typ, n := protowire.ConsumeTag(unknown) + if n < 0 || typ != protowire.BytesType { + return 0 + } + unknown = unknown[n:] + _, n = protowire.ConsumeBytes(unknown) + if n < 0 { + return 0 + } + unknown = unknown[n:] + size += SizeField(num) + protowire.SizeTag(FieldMessage) + n + } + return size +} + +// AppendUnknown appends unknown fields to b in MessageSet format. +// +// For historic reasons, unresolved items in a MessageSet are stored in a +// message's unknown fields section in non-MessageSet format. That is, an +// unknown item with typeID T and value V appears in the unknown fields as +// a field with number T and value V. +// +// This function converts the unknown fields back into MessageSet form. +func AppendUnknown(b, unknown []byte) ([]byte, error) { + for len(unknown) > 0 { + num, typ, n := protowire.ConsumeTag(unknown) + if n < 0 || typ != protowire.BytesType { + return nil, errors.New("invalid data in message set unknown fields") + } + unknown = unknown[n:] + _, n = protowire.ConsumeBytes(unknown) + if n < 0 { + return nil, errors.New("invalid data in message set unknown fields") + } + b = AppendFieldStart(b, num) + b = protowire.AppendTag(b, FieldMessage, protowire.BytesType) + b = append(b, unknown[:n]...) + b = AppendFieldEnd(b) + unknown = unknown[n:] + } + return b, nil +} |