Add rust_grpcio module type.

Adds a new SourceProvider type to generate grpcio code from protos.
Since it's so similar to protobuf, it's basically just a different type
of rust_protobuf.

Bug: 171504899
Test: Example module compiles.
Change-Id: I9882f3ac4d4aeaae0191f2b557e9612b5c7a9ac9

rust/protobuf.go

@@ -22,9 +22,18 @@ var (
 	defaultProtobufFlags = []string{""}
 )
 
+type PluginType int
+
+const (
+	Protobuf PluginType = iota
+	Grpc
+)
+
 func init() {
 	android.RegisterModuleType("rust_protobuf", RustProtobufFactory)
 	android.RegisterModuleType("rust_protobuf_host", RustProtobufHostFactory)
+	android.RegisterModuleType("rust_grpcio", RustGrpcioFactory)
+	android.RegisterModuleType("rust_grpcio_host", RustGrpcioHostFactory)
 }
 
 var _ SourceProvider = (*protobufDecorator)(nil)
@@ -41,15 +50,18 @@ type protobufDecorator struct {
 	*BaseSourceProvider
 
 	Properties ProtobufProperties
+	plugin     PluginType
 }
 
 func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps) android.Path {
 	var protoFlags android.ProtoFlags
-	pluginPath := ctx.Config().HostToolPath(ctx, "protoc-gen-rust")
+	var pluginPath android.Path
 
 	protoFlags.OutTypeFlag = "--rust_out"
+	outDir := android.PathForModuleOut(ctx)
+
+	pluginPath, protoFlags = proto.setupPlugin(ctx, protoFlags, outDir)
 
-	protoFlags.Flags = append(protoFlags.Flags, " --plugin="+pluginPath.String())
 	protoFlags.Flags = append(protoFlags.Flags, defaultProtobufFlags...)
 	protoFlags.Flags = append(protoFlags.Flags, proto.Properties.Proto_flags...)
 
@@ -60,7 +72,6 @@ func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps)
 		ctx.PropertyErrorf("proto", "invalid path to proto file")
 	}
 
-	outDir := android.PathForModuleOut(ctx)
 	stem := proto.BaseSourceProvider.getStem(ctx)
 	// rust protobuf-codegen output <stem>.rs
 	stemFile := android.PathForModuleOut(ctx, stem+".rs")
@@ -79,6 +90,23 @@ func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps)
 	return modFile
 }
 
+func (proto *protobufDecorator) setupPlugin(ctx ModuleContext, protoFlags android.ProtoFlags, outDir android.ModuleOutPath) (android.Path, android.ProtoFlags) {
+	var pluginPath android.Path
+
+	if proto.plugin == Protobuf {
+		pluginPath = ctx.Config().HostToolPath(ctx, "protoc-gen-rust")
+		protoFlags.Flags = append(protoFlags.Flags, "--plugin="+pluginPath.String())
+	} else if proto.plugin == Grpc {
+		pluginPath = ctx.Config().HostToolPath(ctx, "grpc_rust_plugin")
+		protoFlags.Flags = append(protoFlags.Flags, "--grpc_out="+outDir.String())
+		protoFlags.Flags = append(protoFlags.Flags, "--plugin=protoc-gen-grpc="+pluginPath.String())
+	} else {
+		ctx.ModuleErrorf("Unknown protobuf plugin type requested")
+	}
+
+	return pluginPath, protoFlags
+}
+
 func (proto *protobufDecorator) SourceProviderProps() []interface{} {
 	return append(proto.BaseSourceProvider.SourceProviderProps(), &proto.Properties)
 }
@@ -104,10 +132,34 @@ func RustProtobufHostFactory() android.Module {
 	return module.Init()
 }
 
+func RustGrpcioFactory() android.Module {
+	module, _ := NewRustGrpcio(android.HostAndDeviceSupported)
+	return module.Init()
+}
+
+// A host-only variant of rust_protobuf. Refer to rust_protobuf for more details.
+func RustGrpcioHostFactory() android.Module {
+	module, _ := NewRustGrpcio(android.HostSupported)
+	return module.Init()
+}
+
 func NewRustProtobuf(hod android.HostOrDeviceSupported) (*Module, *protobufDecorator) {
 	protobuf := &protobufDecorator{
 		BaseSourceProvider: NewSourceProvider(),
 		Properties:         ProtobufProperties{},
+		plugin:             Protobuf,
+	}
+
+	module := NewSourceProviderModule(hod, protobuf, false)
+
+	return module, protobuf
+}
+
+func NewRustGrpcio(hod android.HostOrDeviceSupported) (*Module, *protobufDecorator) {
+	protobuf := &protobufDecorator{
+		BaseSourceProvider: NewSourceProvider(),
+		Properties:         ProtobufProperties{},
+		plugin:             Grpc,
 	}
 
 	module := NewSourceProviderModule(hod, protobuf, false)

rust/protobuf_test.go

@@ -15,8 +15,10 @@
 package rust
 
 import (
-	"android/soong/android"
+	"strings"
 	"testing"
+
+	"android/soong/android"
 )
 
 func TestRustProtobuf(t *testing.T) {
@@ -28,12 +30,41 @@ func TestRustProtobuf(t *testing.T) {
 			source_stem: "buf",
 		}
 	`)
-	// Check that there's a rule to generate the expected output
-	_ = ctx.ModuleForTests("librust_proto", "android_arm64_armv8-a_source").Output("buf.rs")
-
 	// Check that libprotobuf is added as a dependency.
 	librust_proto := ctx.ModuleForTests("librust_proto", "android_arm64_armv8-a_dylib").Module().(*Module)
 	if !android.InList("libprotobuf", librust_proto.Properties.AndroidMkDylibs) {
 		t.Errorf("libprotobuf dependency missing for rust_protobuf (dependency missing from AndroidMkDylibs)")
 	}
+
+	// Make sure the correct plugin is being used.
+	librust_proto_out := ctx.ModuleForTests("librust_proto", "android_arm64_armv8-a_source").Output("buf.rs")
+	cmd := librust_proto_out.RuleParams.Command
+	if w := "protoc-gen-rust"; !strings.Contains(cmd, w) {
+		t.Errorf("expected %q in %q", w, cmd)
+	}
+
+}
+
+func TestRustGrpcio(t *testing.T) {
+	ctx := testRust(t, `
+		rust_grpcio {
+			name: "librust_grpcio",
+			proto: "buf.proto",
+			crate_name: "rust_grpcio",
+			source_stem: "buf",
+		}
+	`)
+
+	// Check that libprotobuf is added as a dependency.
+	librust_grpcio_module := ctx.ModuleForTests("librust_grpcio", "android_arm64_armv8-a_dylib").Module().(*Module)
+	if !android.InList("libprotobuf", librust_grpcio_module.Properties.AndroidMkDylibs) {
+		t.Errorf("libprotobuf dependency missing for rust_grpcio (dependency missing from AndroidMkDylibs)")
+	}
+
+	// Make sure the correct plugin is being used.
+	librust_grpcio_out := ctx.ModuleForTests("librust_grpcio", "android_arm64_armv8-a_source").Output("buf.rs")
+	cmd := librust_grpcio_out.RuleParams.Command
+	if w := "protoc-gen-grpc"; !strings.Contains(cmd, w) {
+		t.Errorf("expected %q in %q", w, cmd)
+	}
 }

rust/testing.go

@@ -132,6 +132,8 @@ func CreateTestContext() *android.TestContext {
 	ctx.RegisterModuleType("rust_ffi_host", RustFFIHostFactory)
 	ctx.RegisterModuleType("rust_ffi_host_shared", RustFFISharedHostFactory)
 	ctx.RegisterModuleType("rust_ffi_host_static", RustFFIStaticHostFactory)
+	ctx.RegisterModuleType("rust_grpcio", RustGrpcioFactory)
+	ctx.RegisterModuleType("rust_grpcio_host", RustGrpcioHostFactory)
 	ctx.RegisterModuleType("rust_proc_macro", ProcMacroFactory)
 	ctx.RegisterModuleType("rust_protobuf", RustProtobufFactory)
 	ctx.RegisterModuleType("rust_protobuf_host", RustProtobufHostFactory)