github.com/gogo/protobuf@v1.3.2/plugin/oneofcheck/oneofcheck.go (about)

     1  // Protocol Buffers for Go with Gadgets
     2  //
     3  // Copyright (c) 2013, The GoGo Authors. All rights reserved.
     4  // http://github.com/gogo/protobuf
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    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
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    27  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    28  
    29  /*
    30  The oneofcheck plugin is used to check whether oneof is not used incorrectly.
    31  For instance:
    32  An error is caused if a oneof field:
    33    - is used in a face
    34    - is an embedded field
    35  
    36  */
    37  package oneofcheck
    38  
    39  import (
    40  	"fmt"
    41  	"github.com/gogo/protobuf/gogoproto"
    42  	"github.com/gogo/protobuf/protoc-gen-gogo/generator"
    43  	"os"
    44  )
    45  
    46  type plugin struct {
    47  	*generator.Generator
    48  }
    49  
    50  func NewPlugin() *plugin {
    51  	return &plugin{}
    52  }
    53  
    54  func (p *plugin) Name() string {
    55  	return "oneofcheck"
    56  }
    57  
    58  func (p *plugin) Init(g *generator.Generator) {
    59  	p.Generator = g
    60  }
    61  
    62  func (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  
    89  func (p *plugin) GenerateImports(*generator.FileDescriptor) {}
    90  
    91  func init() {
    92  	generator.RegisterPlugin(NewPlugin())
    93  }