mirror of
https://github.com/genuinetools/reg.git
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210 lines
5.3 KiB
Go
210 lines
5.3 KiB
Go
![]() |
// Protocol Buffers for Go with Gadgets
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//
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// Copyright (c) 2013, The GoGo Authors. All rights reserved.
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// http://github.com/gogo/protobuf
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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/*
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The onlyone plugin generates code for the onlyone extension.
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All fields must be nullable and only one of the fields may be set, like a union.
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Two methods are generated
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GetValue() interface{}
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and
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SetValue(v interface{}) (set bool)
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These provide easier interaction with a onlyone.
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The onlyone extension is not called union as this causes compile errors in the C++ generated code.
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There can only be one ;)
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It is enabled by the following extensions:
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- onlyone
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- onlyone_all
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The onlyone plugin also generates a test given it is enabled using one of the following extensions:
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- testgen
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- testgen_all
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Lets look at:
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github.com/gogo/protobuf/test/example/example.proto
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Btw all the output can be seen at:
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github.com/gogo/protobuf/test/example/*
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The following message:
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message U {
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option (gogoproto.onlyone) = true;
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optional A A = 1;
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optional B B = 2;
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}
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given to the onlyone plugin, will generate code which looks a lot like this:
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func (this *U) GetValue() interface{} {
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if this.A != nil {
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return this.A
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}
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if this.B != nil {
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return this.B
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}
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return nil
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}
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func (this *U) SetValue(value interface{}) bool {
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switch vt := value.(type) {
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case *A:
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this.A = vt
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case *B:
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this.B = vt
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default:
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return false
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}
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return true
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}
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and the following test code:
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func TestUUnion(t *testing.T) {
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popr := math_rand.New(math_rand.NewSource(time.Now().UnixNano()))
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p := NewPopulatedU(popr)
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v := p.GetValue()
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msg := &U{}
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if !msg.SetValue(v) {
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t.Fatalf("Union: Could not set Value")
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}
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if !p.Equal(msg) {
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t.Fatalf("%#v !Union Equal %#v", msg, p)
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}
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}
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*/
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package union
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import (
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"github.com/gogo/protobuf/gogoproto"
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"github.com/gogo/protobuf/protoc-gen-gogo/generator"
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)
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type union struct {
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*generator.Generator
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generator.PluginImports
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}
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func NewUnion() *union {
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return &union{}
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}
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func (p *union) Name() string {
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return "union"
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}
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func (p *union) Init(g *generator.Generator) {
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p.Generator = g
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}
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func (p *union) Generate(file *generator.FileDescriptor) {
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p.PluginImports = generator.NewPluginImports(p.Generator)
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for _, message := range file.Messages() {
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if !gogoproto.IsUnion(file.FileDescriptorProto, message.DescriptorProto) {
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continue
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}
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if message.DescriptorProto.HasExtension() {
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panic("onlyone does not currently support extensions")
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}
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if message.DescriptorProto.GetOptions().GetMapEntry() {
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continue
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}
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ccTypeName := generator.CamelCaseSlice(message.TypeName())
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p.P(`func (this *`, ccTypeName, `) GetValue() interface{} {`)
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p.In()
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for _, field := range message.Field {
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fieldname := p.GetFieldName(message, field)
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if fieldname == "Value" {
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panic("cannot have a onlyone message " + ccTypeName + " with a field named Value")
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}
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p.P(`if this.`, fieldname, ` != nil {`)
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p.In()
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p.P(`return this.`, fieldname)
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p.Out()
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p.P(`}`)
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}
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p.P(`return nil`)
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p.Out()
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p.P(`}`)
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p.P(``)
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p.P(`func (this *`, ccTypeName, `) SetValue(value interface{}) bool {`)
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p.In()
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p.P(`switch vt := value.(type) {`)
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p.In()
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for _, field := range message.Field {
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fieldname := p.GetFieldName(message, field)
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goTyp, _ := p.GoType(message, field)
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p.P(`case `, goTyp, `:`)
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p.In()
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p.P(`this.`, fieldname, ` = vt`)
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p.Out()
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}
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p.P(`default:`)
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p.In()
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for _, field := range message.Field {
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fieldname := p.GetFieldName(message, field)
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if field.IsMessage() {
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goTyp, _ := p.GoType(message, field)
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obj := p.ObjectNamed(field.GetTypeName()).(*generator.Descriptor)
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if gogoproto.IsUnion(obj.File(), obj.DescriptorProto) {
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p.P(`this.`, fieldname, ` = new(`, generator.GoTypeToName(goTyp), `)`)
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p.P(`if set := this.`, fieldname, `.SetValue(value); set {`)
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p.In()
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p.P(`return true`)
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p.Out()
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p.P(`}`)
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p.P(`this.`, fieldname, ` = nil`)
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}
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}
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}
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p.P(`return false`)
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p.Out()
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p.P(`}`)
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p.P(`return true`)
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p.Out()
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p.P(`}`)
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}
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}
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func init() {
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generator.RegisterPlugin(NewUnion())
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}
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