protobuf-go/runtime/protoiface/methods.go

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// 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 protoiface
import (
"github.com/golang/protobuf/v2/internal/pragma"
"github.com/golang/protobuf/v2/reflect/protoreflect"
"github.com/golang/protobuf/v2/reflect/protoregistry"
)
// Methoder is an optional interface implemented by generated messages to
// provide fast-path implementations of various operations.
type Methoder interface {
XXX_Methods() *Methods // may return nil
}
// Methods is a set of optional fast-path implementations of various operations.
type Methods struct {
// Flags indicate support for optional features.
Flags MethodFlag
// MarshalAppend appends the wire-format encoding of m to b, returning the result.
// It does not perform required field checks.
MarshalAppend func(b []byte, m protoreflect.ProtoMessage, opts MarshalOptions) ([]byte, error)
// Size returns the size in bytes of the wire-format encoding of m.
Size func(m protoreflect.ProtoMessage) int
// Unmarshal parses the wire-format message in b and places the result in m.
// It does not reset m or perform required field checks.
Unmarshal func(b []byte, m protoreflect.ProtoMessage, opts UnmarshalOptions) error
// IsInitialized returns an error if any required fields in m are not set.
IsInitialized func(m protoreflect.ProtoMessage) error
pragma.NoUnkeyedLiterals
}
// MethodFlag indicates support for optional fast-path features.
type MethodFlag int64
const (
// MethodFlagDeterministicMarshal indicates support for deterministic marshaling.
MethodFlagDeterministicMarshal MethodFlag = 1 << iota
)
// MarshalOptions configure the marshaler.
//
// This type is identical to the one in package proto.
type MarshalOptions struct {
AllowPartial bool
Deterministic bool
proto: replace CachedSize fast-path method with UseCachedSize option Using an option instead of a separate method has several useful properties: It makes it explicit whether the fast-path AppendMarshal is expected to use cached sizes or not. It properly plumbs the decision to use cached sizes through the call stack. Consider the case where message A includes B includes C: If A and C support cached sizes but B does not, we would like to use the size cache in all messages which support it. Placing this decision in the options allows this to work properly with no additional effort. Placing this option in MarshalOptions permits users to request use of existing cached sizes. This is a two-edged sword: There are places where this ability can permit substantial efficiencies, but this is also an exceedingly sharp-edged API. I believe that on balance the benefits outweigh the risks, especially since the prerequisites for using cached sizes are intuitively obvious. (You must have called Size, and you must not have changed the message.) This CL adds a Size method to MarshalOptions, rather than adding a SizeOptions type. Future additions to MarshalOptions may affect the size of the encoded output (e.g., an option to skip encoding unknown fields) and using the same options for both Marshal and Size makes it easier to use a consistent configuration for each. Change-Id: I6adbb55b717dd03d39f067e1d0b7381945000976 Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/171119 Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
2019-04-08 01:18:31 +00:00
UseCachedSize bool
pragma.NoUnkeyedLiterals
}
// UnmarshalOptions configures the unmarshaler.
//
// This type is identical to the one in package proto.
type UnmarshalOptions struct {
AllowPartial bool
DiscardUnknown bool
Resolver *protoregistry.Types
pragma.NoUnkeyedLiterals
}