[#77] protogen: Initial implementation

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

util/protogen/internalgengo/proto_stable_compat.go

@@ -0,0 +1,124 @@
+package internalgengo
+
+import (
+	"google.golang.org/protobuf/compiler/protogen"
+	"google.golang.org/protobuf/reflect/protoreflect"
+)
+
+var protowirePackage = protogen.GoImportPath("google.golang.org/protobuf/encoding/protowire")
+
+func emitStableSize(g *protogen.GeneratedFile, msg *protogen.Message) {
+	fs := sortFields(msg.Fields)
+
+	g.P("// StableSize returns the size of x in protobuf format.")
+	g.P("//")
+	g.P("// Structures with the same field values have the same binary size.")
+	g.P("func (x *", msg.GoIdent.GoName, ") StableSize() (size int) {")
+	g.P("if x == nil { return 0 }")
+	if len(fs) != 0 {
+		for _, f := range fs {
+			if f.Desc.IsList() && marshalers[f.Desc.Kind()].RepeatedDouble && !(f.Desc.Kind() == protoreflect.Uint64Kind && !f.Desc.IsPacked()) {
+				g.P("var n int")
+				break
+			}
+		}
+		for _, f := range fs {
+			emitFieldSize(g, f)
+		}
+	}
+	g.P("return size")
+	g.P("}\n")
+}
+
+func emitSignatureMethods(g *protogen.GeneratedFile, msg *protogen.Message) {
+	// SignedDataSize implementation (only for requests and responses).
+	g.P("// ReadSignedData fills buf with signed data of x.")
+	g.P("// If buffer length is less than x.SignedDataSize(), new buffer is allocated.")
+	g.P("//")
+	g.P("// Returns any error encountered which did not allow writing the data completely.")
+	g.P("// Otherwise, returns the buffer in which the data is written.")
+	g.P("//")
+	g.P("// Structures with the same field values have the same signed data.")
+	g.P("func (x *", msg.GoIdent.GoName, ") SignedDataSize() int {")
+	g.P("return x.GetBody().StableSize()")
+	g.P("}\n")
+
+	// ReadSignedData implementation (only for requests and responses).
+	g.P("// SignedDataSize returns size of the request signed data in bytes.")
+	g.P("//")
+	g.P("// Structures with the same field values have the same signed data size.")
+	g.P("func (x *", msg.GoIdent.GoName, ") ReadSignedData(buf []byte) ([]byte, error) {")
+	g.P("return x.GetBody().MarshalProtobuf(buf), nil")
+	g.P("}\n")
+}
+
+func emitFieldSize(g *protogen.GeneratedFile, f *protogen.Field) {
+	m := marshalers[f.Desc.Kind()]
+	if m.Prefix == "" {
+		g.P("// FIXME missing field marshaler: ", f.GoName, " of type ", f.Desc.Kind().String())
+		g.P(`panic("unimplemented")`)
+		return
+	}
+
+	name := castFieldName(f)
+	if f.Oneof != nil {
+		name = "x." + f.Oneof.GoName
+		g.P("if inner, ok := ", name, ".(*", f.GoIdent.GoName, "); ok {")
+		defer g.P("}")
+		name = "inner." + f.GoName
+	}
+
+	switch {
+	case f.Desc.IsList() && (f.Desc.Kind() == protoreflect.MessageKind || f.Desc.Kind() == protoreflect.Uint64Kind && !f.Desc.IsPacked()):
+		g.P("for i := range ", name, "{")
+		if f.Desc.Kind() == protoreflect.MessageKind {
+			g.P("size += ", protoPackage.Ident("NestedStructureSize"), "(", f.Desc.Number(), ", ", name, "[i])")
+		} else {
+			if f.Desc.Kind() != protoreflect.Uint64Kind {
+				panic("only uint64 unpacked primitive is supported")
+			}
+
+			g.P("size += ", protowirePackage.Ident("SizeGroup"), "(",
+				protowirePackage.Ident("Number"), "(", f.Desc.Number(), "), ",
+				protowirePackage.Ident("SizeVarint"), "(", name, "[i]))")
+		}
+		g.P("}")
+
+	case f.Desc.IsList():
+		if m.RepeatedDouble {
+			g.P("n, _ = ", protoPackage.Ident("Repeated"+m.Prefix+"Size"), "(", f.Desc.Number(), ", ", name, ")")
+			g.P("size += n")
+		} else {
+			g.P("size += ", protoPackage.Ident("Repeated"+m.Prefix+"Size"), "(", f.Desc.Number(), ", ", name, ")")
+		}
+	default:
+		g.P("size += ", protoPackage.Ident(m.Prefix+"Size"), "(", f.Desc.Number(), ", ", name, ")")
+	}
+}
+
+type marshalerDesc struct {
+	Prefix         string
+	RepeatedDouble bool
+}
+
+// Unused kinds are commented.
+var marshalers = map[protoreflect.Kind]marshalerDesc{
+	protoreflect.BoolKind:  {Prefix: "Bool"},
+	protoreflect.EnumKind:  {Prefix: "Enum"},
+	protoreflect.Int32Kind: {Prefix: "Int32", RepeatedDouble: true},
+	// protoreflect.Sint32Kind:   "",
+	protoreflect.Uint32Kind: {Prefix: "UInt32", RepeatedDouble: true},
+	protoreflect.Int64Kind:  {Prefix: "Int64", RepeatedDouble: true},
+	// protoreflect.Sint64Kind:   "",
+	protoreflect.Uint64Kind: {Prefix: "UInt64", RepeatedDouble: true},
+	// protoreflect.Sfixed32Kind: "",
+	protoreflect.Fixed32Kind: {Prefix: "Fixed32", RepeatedDouble: true},
+	// protoreflect.FloatKind:    "",
+	// protoreflect.Sfixed64Kind: "",
+	protoreflect.Fixed64Kind: {Prefix: "Fixed64", RepeatedDouble: true},
+	protoreflect.DoubleKind:  {Prefix: "Float64"},
+	protoreflect.StringKind:  {Prefix: "String"},
+	protoreflect.BytesKind:   {Prefix: "Bytes"},
+	protoreflect.MessageKind: {Prefix: "NestedStructure"},
+	// protoreflect.GroupKind:    "",
+}