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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 protodesc
import (
"fmt"
"os"
"sync"
"google.golang.org/protobuf/internal/editiondefaults"
"google.golang.org/protobuf/internal/filedesc"
"google.golang.org/protobuf/proto"
"google.golang.org/protobuf/reflect/protoreflect"
"google.golang.org/protobuf/types/descriptorpb"
gofeaturespb "google.golang.org/protobuf/types/gofeaturespb"
)
var defaults = &descriptorpb.FeatureSetDefaults{}
var defaultsCacheMu sync.Mutex
var defaultsCache = make(map[filedesc.Edition]*descriptorpb.FeatureSet)
func init() {
err := proto.Unmarshal(editiondefaults.Defaults, defaults)
if err != nil {
fmt.Fprintf(os.Stderr, "unmarshal editions defaults: %v\n", err)
os.Exit(1)
}
}
func fromEditionProto(epb descriptorpb.Edition) filedesc.Edition {
return filedesc.Edition(epb)
}
func toEditionProto(ed filedesc.Edition) descriptorpb.Edition {
switch ed {
case filedesc.EditionUnknown:
return descriptorpb.Edition_EDITION_UNKNOWN
case filedesc.EditionProto2:
return descriptorpb.Edition_EDITION_PROTO2
case filedesc.EditionProto3:
return descriptorpb.Edition_EDITION_PROTO3
case filedesc.Edition2023:
return descriptorpb.Edition_EDITION_2023
default:
panic(fmt.Sprintf("unknown value for edition: %v", ed))
}
}
func getFeatureSetFor(ed filedesc.Edition) *descriptorpb.FeatureSet {
defaultsCacheMu.Lock()
defer defaultsCacheMu.Unlock()
if def, ok := defaultsCache[ed]; ok {
return def
}
edpb := toEditionProto(ed)
if defaults.GetMinimumEdition() > edpb || defaults.GetMaximumEdition() < edpb {
// This should never happen protodesc.(FileOptions).New would fail when
// initializing the file descriptor.
// This most likely means the embedded defaults were not updated.
fmt.Fprintf(os.Stderr, "internal error: unsupported edition %v (did you forget to update the embedded defaults (i.e. the bootstrap descriptor proto)?)\n", edpb)
os.Exit(1)
}
fs := defaults.GetDefaults()[0].GetFeatures()
// Using a linear search for now.
// Editions are guaranteed to be sorted and thus we could use a binary search.
// Given that there are only a handful of editions (with one more per year)
// there is not much reason to use a binary search.
for _, def := range defaults.GetDefaults() {
if def.GetEdition() <= edpb {
fs = def.GetFeatures()
} else {
break
}
}
defaultsCache[ed] = fs
return fs
}
// mergeEditionFeatures merges the parent and child feature sets. This function
// should be used when initializing Go descriptors from descriptor protos which
// is why the parent is a filedesc.EditionsFeatures (Go representation) while
// the child is a descriptorproto.FeatureSet (protoc representation).
// Any feature set by the child overwrites what is set by the parent.
func mergeEditionFeatures(parentDesc protoreflect.Descriptor, child *descriptorpb.FeatureSet) filedesc.EditionFeatures {
var parentFS filedesc.EditionFeatures
switch p := parentDesc.(type) {
case *filedesc.File:
parentFS = p.L1.EditionFeatures
case *filedesc.Message:
parentFS = p.L1.EditionFeatures
default:
panic(fmt.Sprintf("unknown parent type %T", parentDesc))
}
if child == nil {
return parentFS
}
if fp := child.FieldPresence; fp != nil {
parentFS.IsFieldPresence = *fp == descriptorpb.FeatureSet_LEGACY_REQUIRED ||
*fp == descriptorpb.FeatureSet_EXPLICIT
parentFS.IsLegacyRequired = *fp == descriptorpb.FeatureSet_LEGACY_REQUIRED
}
if et := child.EnumType; et != nil {
parentFS.IsOpenEnum = *et == descriptorpb.FeatureSet_OPEN
}
if rfe := child.RepeatedFieldEncoding; rfe != nil {
parentFS.IsPacked = *rfe == descriptorpb.FeatureSet_PACKED
}
if utf8val := child.Utf8Validation; utf8val != nil {
parentFS.IsUTF8Validated = *utf8val == descriptorpb.FeatureSet_VERIFY
}
if me := child.MessageEncoding; me != nil {
parentFS.IsDelimitedEncoded = *me == descriptorpb.FeatureSet_DELIMITED
}
if jf := child.JsonFormat; jf != nil {
parentFS.IsJSONCompliant = *jf == descriptorpb.FeatureSet_ALLOW
}
if goFeatures, ok := proto.GetExtension(child, gofeaturespb.E_Go).(*gofeaturespb.GoFeatures); ok && goFeatures != nil {
if luje := goFeatures.LegacyUnmarshalJsonEnum; luje != nil {
parentFS.GenerateLegacyUnmarshalJSON = *luje
}
}
return parentFS
}
// initFileDescFromFeatureSet initializes editions related fields in fd based
// on fs. If fs is nil it is assumed to be an empty featureset and all fields
// will be initialized with the appropriate default. fd.L1.Edition must be set
// before calling this function.
func initFileDescFromFeatureSet(fd *filedesc.File, fs *descriptorpb.FeatureSet) {
dfs := getFeatureSetFor(fd.L1.Edition)
// initialize the featureset with the defaults
fd.L1.EditionFeatures = mergeEditionFeatures(fd, dfs)
// overwrite any options explicitly specified
fd.L1.EditionFeatures = mergeEditionFeatures(fd, fs)
}