Convert Request and ResponseWriter to interfaces (#10)

README.md

@@ -77,9 +77,9 @@ func main() {
 
 func handle(
 	_ context.Context,
-  _ *protoplugin.HandlerEnv,
-	responseWriter *protoplugin.ResponseWriter,
-	request *protoplugin.Request,
+  _ protoplugin.PluginEnv,
+	responseWriter protoplugin.ResponseWriter,
+	request protoplugin.Request,
 ) error {
 	// Set the flag indicating that we support proto3 optionals. We don't even use them in this
 	// plugin, but protoc will error if it encounters a proto3 file with an optional but the
@@ -193,7 +193,7 @@ Errors or warnings will also be produced if:
   a duplicate name is plugin authoring issue, and here at Buf, we've seen a lot of plugins have this issue!
 - Any file path is not cleaned.
 
-By default, these are errors, however if `WithLenientResponseValidation` is set, these will be warnings.
+By default, these are errors, however if `WithLenientValidation` is set, these will be warnings.
 
 ## What this library is not
 

env.go

@@ -16,7 +16,7 @@ package protoplugin
 
 import "io"
 
-// Env represents an environment for a plugin to run within.
+// Env represents an environment.
 //
 // This wraps items like args, environment variables, and stdio.
 //
@@ -37,13 +37,13 @@ type Env struct {
 	Stderr io.Writer
 }
 
-// HandlerEnv represents an environment that a Handler is run within.
+// PluginEnv represents an environment that a plugin is run within.
 //
-// This provides the environment variables and stderr to a Handler. A Handler should not have
+// This provides the environment variables and stderr. A plugin implementation should not have
 // access to stdin, stdout, or the args, as these are controlled by the plugin framework.
 //
 // When calling Main, this uses the values os.Environ and os.Stderr.
-type HandlerEnv struct {
+type PluginEnv struct {
 	// Environment are the environment variables.
 	Environ []string
 	// Stderr is the stderr for the plugin.

handler.go

@@ -44,21 +44,21 @@ type Handler interface {
 	// (for example, a missing option), this error should be added to the response via SetError.
 	Handle(
 		ctx context.Context,
-		handlerEnv *HandlerEnv,
-		responseWriter *ResponseWriter,
-		request *Request,
+		pluginEnv PluginEnv,
+		responseWriter ResponseWriter,
+		request Request,
 	) error
 }
 
 // HandlerFunc is a function that implements Handler.
-type HandlerFunc func(context.Context, *HandlerEnv, *ResponseWriter, *Request) error
+type HandlerFunc func(context.Context, PluginEnv, ResponseWriter, Request) error
 
 // Handle implements Handler.
 func (h HandlerFunc) Handle(
 	ctx context.Context,
-	handlerEnv *HandlerEnv,
-	responseWriter *ResponseWriter,
-	request *Request,
+	pluginEnv PluginEnv,
+	responseWriter ResponseWriter,
+	request Request,
 ) error {
-	return h(ctx, handlerEnv, responseWriter, request)
+	return h(ctx, pluginEnv, responseWriter, request)
 }

internal/examples/protoc-gen-protogen-simple/main.go

@@ -36,9 +36,9 @@ func main() {
 
 func handle(
 	_ context.Context,
-	_ *protoplugin.HandlerEnv,
-	responseWriter *protoplugin.ResponseWriter,
-	request *protoplugin.Request,
+	_ protoplugin.PluginEnv,
+	responseWriter protoplugin.ResponseWriter,
+	request protoplugin.Request,
 ) error {
 	plugin, err := protogen.Options{}.New(request.CodeGeneratorRequest())
 	if err != nil {

internal/examples/protoc-gen-protoreflect-simple/main.go

@@ -38,9 +38,9 @@ func main() {
 
 func handle(
 	_ context.Context,
-	_ *protoplugin.HandlerEnv,
-	responseWriter *protoplugin.ResponseWriter,
-	request *protoplugin.Request,
+	_ protoplugin.PluginEnv,
+	responseWriter protoplugin.ResponseWriter,
+	request protoplugin.Request,
 ) error {
 	// Set the flag indicating that we support proto3 optionals. We don't even use them in this
 	// plugin, but protoc will error if it encounters a proto3 file with an optional but the

internal/examples/protoc-gen-simple/main.go

@@ -34,9 +34,9 @@ func main() {
 
 func handle(
 	_ context.Context,
-	_ *protoplugin.HandlerEnv,
-	responseWriter *protoplugin.ResponseWriter,
-	request *protoplugin.Request,
+	_ protoplugin.PluginEnv,
+	responseWriter protoplugin.ResponseWriter,
+	request protoplugin.Request,
 ) error {
 	// Set the flag indicating that we support proto3 optionals. We don't even use them in this
 	// plugin, but protoc will error if it encounters a proto3 file with an optional but the

protoplugin.go

@@ -30,7 +30,7 @@ import (
 
 var (
 	// osEnv is the os-based Env used in Main.
-	osEnv = &Env{
+	osEnv = Env{
 		Args:    os.Args[1:],
 		Environ: os.Environ(),
 		Stdin:   os.Stdin,
@@ -77,7 +77,7 @@ func Main(handler Handler, options ...MainOption) {
 // when writing plugin tests, or if you want to use your own custom logic for main functions.
 func Run(
 	ctx context.Context,
-	env *Env,
+	env Env,
 	handler Handler,
 	options ...RunOption,
 ) error {
@@ -114,8 +114,8 @@ func WithVersion(version string) RunOption {
 	})
 }
 
-// WithLenientResponseValidation returns a new GenerateOption that says handle non-critical issues with response
-// construction as warnings that will be handled by the given warning handler.
+// WithLenientValidation returns a new RunOption that says handle non-critical issues
+// as warnings that will be handled by the given warning handler.
 //
 // This allows the following issues to result in warnings instead of errors:
 //
@@ -137,19 +137,19 @@ func WithVersion(version string) RunOption {
 //
 // The default is to error on these issues.
 //
-// Implementers of lenientResponseValidationErrorFunc can assume that errors passed will be non-nil and have non-empty
+// Implementers of lenientValidationErrorFunc can assume that errors passed will be non-nil and have non-empty
 // values for err.Error().
-func WithLenientResponseValidation(lenientResponseValidateErrorFunc func(error)) RunOption {
+func WithLenientValidation(lenientValidateErrorFunc func(error)) RunOption {
 	return optsFunc(func(opts *opts) {
-		opts.lenientResponseValidateErrorFunc = lenientResponseValidateErrorFunc
+		opts.lenientValidateErrorFunc = lenientValidateErrorFunc
 	})
 }
 
 /// *** PRIVATE ***
 
 func run(
 	ctx context.Context,
-	env *Env,
+	env Env,
 	handler Handler,
 	opts *opts,
 ) error {
@@ -173,16 +173,23 @@ func run(
 	if err := proto.Unmarshal(input, codeGeneratorRequest); err != nil {
 		return err
 	}
-	codeGeneratorResponse, err := generate(
+	request, err := NewRequest(codeGeneratorRequest)
+	if err != nil {
+		return err
+	}
+	responseWriter := NewResponseWriter(ResponseWriterWithLenientValidation(opts.lenientValidateErrorFunc))
+	if err := handler.Handle(
 		ctx,
-		&HandlerEnv{
+		PluginEnv{
 			Environ: env.Environ,
 			Stderr:  env.Stderr,
 		},
-		codeGeneratorRequest,
-		handler,
-		opts,
-	)
+		responseWriter,
+		request,
+	); err != nil {
+		return err
+	}
+	codeGeneratorResponse, err := responseWriter.ToCodeGeneratorResponse()
 	if err != nil {
 		return err
 	}
@@ -194,24 +201,6 @@ func run(
 	return err
 }
 
-func generate(
-	ctx context.Context,
-	handlerEnv *HandlerEnv,
-	codeGeneratorRequest *pluginpb.CodeGeneratorRequest,
-	handler Handler,
-	opts *opts,
-) (*pluginpb.CodeGeneratorResponse, error) {
-	request, err := newRequest(codeGeneratorRequest)
-	if err != nil {
-		return nil, err
-	}
-	responseWriter := newResponseWriter(opts.lenientResponseValidateErrorFunc)
-	if err := handler.Handle(ctx, handlerEnv, responseWriter, request); err != nil {
-		return nil, err
-	}
-	return responseWriter.toCodeGeneratorResponse()
-}
-
 // withCancelInterruptSignal returns a context that is cancelled if interrupt signals are sent.
 func withCancelInterruptSignal(ctx context.Context) (context.Context, context.CancelFunc) {
 	interruptSignalC, closer := newInterruptSignalChannel()
@@ -237,8 +226,8 @@ func newInterruptSignalChannel() (<-chan os.Signal, func()) {
 }
 
 type opts struct {
-	version                          string
-	lenientResponseValidateErrorFunc func(error)
+	version                  string
+	lenientValidateErrorFunc func(error)
 }
 
 func newOpts() *opts {

protoplugin_test.go

@@ -47,9 +47,9 @@ func TestBasic(t *testing.T) {
 		HandlerFunc(
 			func(
 				ctx context.Context,
-				handlerEnv *HandlerEnv,
-				responseWriter *ResponseWriter,
-				request *Request,
+				pluginEnv PluginEnv,
+				responseWriter ResponseWriter,
+				request Request,
 			) error {
 				for _, fileDescriptorProto := range request.FileDescriptorProtosToGenerate() {
 					topLevelMessageNames := make([]string, len(fileDescriptorProto.GetMessageType()))
@@ -77,14 +77,14 @@ func TestWithVersionOption(t *testing.T) {
 		stdout := bytes.NewBuffer(nil)
 		err := Run(
 			context.Background(),
-			&Env{
+			Env{
 				Args:    args,
 				Environ: nil,
 				Stdin:   iotest.ErrReader(io.EOF),
 				Stdout:  stdout,
 				Stderr:  io.Discard,
 			},
-			HandlerFunc(func(ctx context.Context, _ *HandlerEnv, _ *ResponseWriter, _ *Request) error { return nil }),
+			HandlerFunc(func(ctx context.Context, _ PluginEnv, _ ResponseWriter, _ Request) error { return nil }),
 			runOptions...,
 		)
 		return stdout.String(), err
@@ -129,7 +129,7 @@ func testBasic(
 
 	err = Run(
 		ctx,
-		&Env{
+		Env{
 			Args:    nil,
 			Environ: nil,
 			Stdin:   stdin,