1// Protocol Buffers for Go with Gadgets
2//
3// Copyright (c) 2013, The GoGo Authors. All rights reserved.
4// http://github.com/gogo/protobuf
5//
6// Redistribution and use in source and binary forms, with or without
7// modification, are permitted provided that the following conditions are
8// met:
9//
10//     * Redistributions of source code must retain the above copyright
11// notice, this list of conditions and the following disclaimer.
12//     * Redistributions in binary form must reproduce the above
13// copyright notice, this list of conditions and the following disclaimer
14// in the documentation and/or other materials provided with the
15// distribution.
16//
17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29/*
30The oneofcheck plugin is used to check whether oneof is not used incorrectly.
31For instance:
32An error is caused if a oneof field:
33  - is used in a face
34  - is an embedded field
35
36*/
37package oneofcheck
38
39import (
40	"fmt"
41	"github.com/gogo/protobuf/gogoproto"
42	"github.com/gogo/protobuf/protoc-gen-gogo/generator"
43	"os"
44)
45
46type plugin struct {
47	*generator.Generator
48}
49
50func NewPlugin() *plugin {
51	return &plugin{}
52}
53
54func (p *plugin) Name() string {
55	return "oneofcheck"
56}
57
58func (p *plugin) Init(g *generator.Generator) {
59	p.Generator = g
60}
61
62func (p *plugin) Generate(file *generator.FileDescriptor) {
63	for _, msg := range file.Messages() {
64		face := gogoproto.IsFace(file.FileDescriptorProto, msg.DescriptorProto)
65		for _, field := range msg.GetField() {
66			if field.OneofIndex == nil {
67				continue
68			}
69			if face {
70				fmt.Fprintf(os.Stderr, "ERROR: field %v.%v cannot be in a face and oneof\n", generator.CamelCase(*msg.Name), generator.CamelCase(*field.Name))
71				os.Exit(1)
72			}
73			if gogoproto.IsEmbed(field) {
74				fmt.Fprintf(os.Stderr, "ERROR: field %v.%v cannot be in an oneof and an embedded field\n", generator.CamelCase(*msg.Name), generator.CamelCase(*field.Name))
75				os.Exit(1)
76			}
77			if !gogoproto.IsNullable(field) {
78				fmt.Fprintf(os.Stderr, "ERROR: field %v.%v cannot be in an oneof and a non-nullable field\n", generator.CamelCase(*msg.Name), generator.CamelCase(*field.Name))
79				os.Exit(1)
80			}
81			if gogoproto.IsUnion(file.FileDescriptorProto, msg.DescriptorProto) {
82				fmt.Fprintf(os.Stderr, "ERROR: field %v.%v cannot be in an oneof and in an union (deprecated)\n", generator.CamelCase(*msg.Name), generator.CamelCase(*field.Name))
83				os.Exit(1)
84			}
85		}
86	}
87}
88
89func (p *plugin) GenerateImports(*generator.FileDescriptor) {}
90
91func init() {
92	generator.RegisterPlugin(NewPlugin())
93}
94