github.com/RomiChan/protobuf@v0.1.1-0.20230204044148-2ed269a2e54d/internal/generator/init.go

// protocolbuffers/protobuf-go cmd/protoc-gen-go/internal_gengo/init.go
// https://github.com/protocolbuffers/protobuf-go/blob/master/cmd/protoc-gen-go/internal_gengo/init.go
//
//	Copyright © 2019 The Go Authors. All rights reserved.
//	Portions Copyright © 2021 RomiChan
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package generator

import (
	"unicode"
	"unicode/utf8"

	"google.golang.org/protobuf/compiler/protogen"
	"google.golang.org/protobuf/encoding/protowire"
	"google.golang.org/protobuf/types/descriptorpb"
)

type fileInfo struct {
	*protogen.File

	allEnums      []*enumInfo
	allMessages   []*messageInfo
	allExtensions []*extensionInfo

	allEnumsByPtr         map[*enumInfo]int    // value is index into allEnums
	allMessagesByPtr      map[*messageInfo]int // value is index into allMessages
	allMessageFieldsByPtr map[*messageInfo]*structFields

	comparable bool
}

type structFields struct {
	count      int
	unexported map[int]string
}

func (sf *structFields) append(name string) {
	if r, _ := utf8.DecodeRuneInString(name); !unicode.IsUpper(r) {
		if sf.unexported == nil {
			sf.unexported = make(map[int]string)
		}
		sf.unexported[sf.count] = name
	}
	sf.count++
}

func newFileInfo(file *protogen.File) *fileInfo {
	f := &fileInfo{File: file}

	// Collect all enums, messages, and extensions in "flattened ordering".
	// See filetype.TypeBuilder.
	var walkMessages func([]*protogen.Message, func(*protogen.Message))
	walkMessages = func(messages []*protogen.Message, f func(*protogen.Message)) {
		for _, m := range messages {
			f(m)
			walkMessages(m.Messages, f)
		}
	}
	initEnumInfos := func(enums []*protogen.Enum) {
		for _, enum := range enums {
			f.allEnums = append(f.allEnums, newEnumInfo(f, enum))
		}
	}
	initMessageInfos := func(messages []*protogen.Message) {
		for _, message := range messages {
			f.allMessages = append(f.allMessages, newMessageInfo(f, message))
		}
	}
	initExtensionInfos := func(extensions []*protogen.Extension) {
		for _, extension := range extensions {
			f.allExtensions = append(f.allExtensions, newExtensionInfo(f, extension))
		}
	}
	initEnumInfos(f.Enums)
	initMessageInfos(f.Messages)
	initExtensionInfos(f.Extensions)
	walkMessages(f.Messages, func(m *protogen.Message) {
		initEnumInfos(m.Enums)
		initMessageInfos(m.Messages)
		initExtensionInfos(m.Extensions)
	})

	// Derive a reverse mapping of enum and message pointers to their index
	// in allEnums and allMessages.
	if len(f.allEnums) > 0 {
		f.allEnumsByPtr = make(map[*enumInfo]int)
		for i, e := range f.allEnums {
			f.allEnumsByPtr[e] = i
		}
	}
	if len(f.allMessages) > 0 {
		f.allMessagesByPtr = make(map[*messageInfo]int)
		f.allMessageFieldsByPtr = make(map[*messageInfo]*structFields)
		for i, m := range f.allMessages {
			f.allMessagesByPtr[m] = i
			f.allMessageFieldsByPtr[m] = new(structFields)
		}
	}

	return f
}

type enumInfo struct {
	*protogen.Enum
}

func newEnumInfo(_ *fileInfo, enum *protogen.Enum) *enumInfo {
	e := &enumInfo{Enum: enum}
	return e
}

type messageInfo struct {
	*protogen.Message

	isTracked bool
}

func newMessageInfo(_ *fileInfo, message *protogen.Message) *messageInfo {
	m := &messageInfo{Message: message}
	m.isTracked = isTrackedMessage(m)
	return m
}

// isTrackedMessage reports whether field tracking is enabled on the message.
func isTrackedMessage(m *messageInfo) (tracked bool) {
	const trackFieldUseFieldNumber = 37383685

	// Decode the option from unknown fields to avoid a dependency on the
	// annotation proto from protoc-gen-go.
	b := m.Desc.Options().(*descriptorpb.MessageOptions).ProtoReflect().GetUnknown()
	for len(b) > 0 {
		num, typ, n := protowire.ConsumeTag(b)
		b = b[n:]
		if num == trackFieldUseFieldNumber && typ == protowire.VarintType {
			v, _ := protowire.ConsumeVarint(b)
			tracked = protowire.DecodeBool(v)
		}
		m := protowire.ConsumeFieldValue(num, typ, b)
		b = b[m:]
	}
	return tracked
}

type extensionInfo struct {
	*protogen.Extension
}

func newExtensionInfo(_ *fileInfo, extension *protogen.Extension) *extensionInfo {
	x := &extensionInfo{Extension: extension}
	return x
}