mirror of
https://github.com/protocolbuffers/protobuf-go.git
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35ec98fdcb
This removes yet another set of dependencies of v2 on v1.
The only remaining dependency are in the _test.go files,
primarily for proto.Equal.
Changes made:
* cmd/protoc-gen-go no longer generates any functionality that depends
on the v1 package, and instead only depends on v2.
* internal/fileinit.FileBuilder.MessageOutputTypes is switched from
protoreflect.MessageType to protoimpl.MessageType since the
implementation must be fully inialized before registration occurs.
* The test for internal/legacy/file_test.go is switched to a legacy_test
package to avoid a cyclic dependency.
This requires Load{Enum,Message,File}Desc to be exported.
Change-Id: I43e2fe64cff4eea204258ce11e791aca5eb6e569
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/169298
Reviewed-by: Damien Neil <dneil@google.com>
81 lines
2.5 KiB
Go
81 lines
2.5 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package legacy
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import (
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"bytes"
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"compress/gzip"
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"io/ioutil"
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"sync"
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"github.com/golang/protobuf/v2/proto"
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pref "github.com/golang/protobuf/v2/reflect/protoreflect"
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descriptorpb "github.com/golang/protobuf/v2/types/descriptor"
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)
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// Every enum and message type generated by protoc-gen-go since commit 2fc053c5
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// on February 25th, 2016 has had a method to get the raw descriptor.
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// Types that were not generated by protoc-gen-go or were generated prior
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// to that version are not supported.
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//
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// The []byte returned is the encoded form of a FileDescriptorProto message
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// compressed using GZIP. The []int is the path from the top-level file
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// to the specific message or enum declaration.
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type (
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enumV1 interface {
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EnumDescriptor() ([]byte, []int)
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}
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messageV1 interface {
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Descriptor() ([]byte, []int)
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}
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)
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var fileDescCache sync.Map // map[*byte]*descriptorpb.FileDescriptorProto
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// LoadFileDesc unmarshals b as a compressed FileDescriptorProto message.
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//
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// This assumes that b is immutable and that b does not refer to part of a
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// concatenated series of GZIP files (which would require shenanigans that
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// rely on the concatenation properties of both protobufs and GZIP).
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// File descriptors generated by protoc-gen-go do not rely on that property.
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//
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// This is exported for testing purposes.
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func LoadFileDesc(b []byte) *descriptorpb.FileDescriptorProto {
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// Fast-path: check whether we already have a cached file descriptor.
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if fd, ok := fileDescCache.Load(&b[0]); ok {
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return fd.(*descriptorpb.FileDescriptorProto)
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}
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// Slow-path: decompress and unmarshal the file descriptor proto.
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fd := new(descriptorpb.FileDescriptorProto)
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zr, err := gzip.NewReader(bytes.NewReader(b))
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if err != nil {
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panic(err)
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}
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b, err = ioutil.ReadAll(zr)
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if err != nil {
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panic(err)
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}
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err = proto.UnmarshalOptions{DiscardUnknown: true}.Unmarshal(b, fd)
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if err != nil {
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panic(err)
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}
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if fd, ok := fileDescCache.LoadOrStore(&b[0], fd); ok {
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return fd.(*descriptorpb.FileDescriptorProto)
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}
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return fd
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}
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// parentFileDescriptor returns the parent protoreflect.FileDescriptor for the
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// provide descriptor. It returns nil if there is no parent.
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func parentFileDescriptor(d pref.Descriptor) pref.FileDescriptor {
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for ok := true; ok; d, ok = d.Parent() {
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if fd, _ := d.(pref.FileDescriptor); fd != nil {
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return fd
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}
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}
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return nil
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}
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