encoding/protobuf: support integer enums

Also support mappings to different representations.

For string disjunctions: associate #enumValue with string

For int disjunctions: map definition references
to symbols.

Change-Id: I7d6dec1798c26a43d40f9c6e8db29b26e8499866
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/9402
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

cmd/cue/cmd/flags.go

@@ -43,6 +43,7 @@ const (
 	flagPath        flagName = "path"
 	flagFiles       flagName = "files"
 	flagProtoPath   flagName = "proto_path"
+	flagProtoEnum   flagName = "proto_enum"
 	flagWithContext flagName = "with-context"
 	flagOut         flagName = "out"
 	flagOutFile     flagName = "outfile"
@@ -79,6 +80,7 @@ func addOrphanFlags(f *pflag.FlagSet) {
 	f.Bool(string(flagList), false, "concatenate multiple objects into a list")
 	f.Bool(string(flagWithContext), false, "import as object with contextual data")
 	f.StringArrayP(string(flagProtoPath), "I", nil, "paths in which to search for imports")
+	f.String(string(flagProtoEnum), "int", "mode for rendering enums (int|json)")
 	f.StringP(string(flagGlob), "n", "", "glob filter for file names")
 	f.Bool(string(flagMerge), true, "merge non-CUE files")
 }

cmd/cue/cmd/get_go.go

@@ -676,6 +676,12 @@ func (e *extractor) reportDecl(x *ast.GenDecl) (a []cueast.Decl) {
 			typ := e.pkg.TypesInfo.TypeOf(v.Name)
 			enums := e.consts[typ.String()]
 			name := v.Name.Name
+			mapNamed := false
+			underlying := e.pkg.TypesInfo.TypeOf(v.Type)
+			if b, ok := underlying.Underlying().(*types.Basic); ok && b.Kind() != types.String {
+				mapNamed = true
+			}
+
 			switch tn, ok := e.pkg.TypesInfo.Defs[v.Name].(*types.TypeName); {
 			case ok:
 				if altType := e.altType(tn.Type()); altType != nil {
@@ -695,8 +701,7 @@ func (e *extractor) reportDecl(x *ast.GenDecl) (a []cueast.Decl) {
 					a = append(a, e.def(x.Doc, name, s, true))
 					break
 				}
-				// TODO: only print original type if value is not marked as enum.
-				underlying := e.pkg.TypesInfo.TypeOf(v.Type)
+
 				f, _ := e.makeField(name, cuetoken.ISA, underlying, x.Doc, true)
 				a = append(a, f)
 				cueast.SetRelPos(f, cuetoken.NewSection)
@@ -708,20 +713,44 @@ func (e *extractor) reportDecl(x *ast.GenDecl) (a []cueast.Decl) {
 				cueast.AddComment(a[len(a)-1], internal.NewComment(false, enumName))
 
 				// Constants are mapped as definitions.
-				var x cueast.Expr = e.ident(enums[0], true)
-				cueast.SetRelPos(x, cuetoken.Newline)
-				for _, v := range enums[1:] {
-					y := e.ident(v, true)
-					cueast.SetRelPos(y, cuetoken.Newline)
-					x = cueast.NewBinExpr(cuetoken.OR, x, y)
+				var exprs []cueast.Expr
+				var named []cueast.Decl
+				for _, v := range enums {
+					label := cueast.NewString(v)
+					cueast.SetRelPos(label, cuetoken.Blank)
+
+					var x cueast.Expr = e.ident(v, true)
+					cueast.SetRelPos(x, cuetoken.Newline)
+					exprs = append(exprs, x)
+
+					if !mapNamed {
+						continue
+					}
+
+					named = append(named, &cueast.Field{
+						Label: label,
+						Value: e.ident(v, true),
+					})
+				}
+
+				addField := func(label string, exprs []cueast.Expr) {
+					f := &cueast.Field{
+						Label: cueast.NewIdent(label),
+						Value: cueast.NewBinExpr(cuetoken.OR, exprs...),
+					}
+					cueast.SetRelPos(f, cuetoken.NewSection)
+					a = append(a, f)
 				}
-				// a = append(a, e.def(nil, enumName, x, true))
-				f := &cueast.Field{
-					Label: cueast.NewIdent(enumName),
-					Value: x,
+
+				addField(enumName, exprs)
+				if len(named) > 0 {
+					f := &cueast.Field{
+						Label: cueast.NewIdent("#values_" + name),
+						Value: &cueast.StructLit{Elts: named},
+					}
+					cueast.SetRelPos(f, cuetoken.NewSection)
+					a = append(a, f)
 				}
-				a = append(a, f)
-				cueast.SetRelPos(f, cuetoken.NewSection)
 			}
 		}
 

cmd/cue/cmd/import.go

@@ -334,10 +334,11 @@ func protoMode(b *buildPlan) error {
 	}
 
 	c := &protobuf.Config{
-		Root:    root,
-		Module:  module,
-		Paths:   b.encConfig.ProtoPath,
-		PkgName: b.encConfig.PkgName,
+		Root:     root,
+		Module:   module,
+		Paths:    b.encConfig.ProtoPath,
+		PkgName:  b.encConfig.PkgName,
+		EnumMode: flagProtoEnum.String(b.cmd),
 	}
 	if module != "" {
 		// We only allow imports from packages within the module if an actual

cmd/cue/cmd/testdata/script/get_go_types.txt

@@ -120,6 +120,13 @@ const (
 	High
 )
 
+type Level2 Level
+
+const (
+	AnotherLevel1 Level2 = iota + 4
+	AnotherLevel2
+)
+
 type CustomJSON struct {
 }
 
@@ -432,6 +439,13 @@ _#internalIdentifier: #Identifier & "internal"
 	#Medium |
 	#High
 
+#values_Level: {
+	Unknown: #Unknown
+	Low:     #Low
+	Medium:  #Medium
+	High:    #High
+}
+
 // Block comment.
 //  Indented.
 //
@@ -443,6 +457,20 @@ _#internalIdentifier: #Identifier & "internal"
 #Medium: #Level & 2
 #High:   #Level & 3
 
+#Level2: #Level // #enumLevel2
+
+#enumLevel2:
+	#AnotherLevel1 |
+	#AnotherLevel2
+
+#values_Level2: {
+	AnotherLevel1: #AnotherLevel1
+	AnotherLevel2: #AnotherLevel2
+}
+
+#AnotherLevel1: #Level2 & 4
+#AnotherLevel2: #Level2 & 5
+
 #CustomJSON: _
 
 #CustomYAML: {

cmd/cue/cmd/testdata/script/import_proto.txt

@@ -37,6 +37,11 @@ option go_package = "acme.com/api/mixer/v1";
 
 // Attributes defines attributes.
 message Attributes {
+  enum Type {
+    TYPE_A = 1;
+    TYPE_B = 2;
+  }
+
   // A map of attribute name to its value.
   map<string, AttributeValue> attributes = 1;
 
@@ -171,6 +176,18 @@ import (
 
 // Attributes defines attributes.
 #Attributes: {
+	#Type:
+		#TYPE_A |
+		#TYPE_B
+
+	#TYPE_A: 1
+	#TYPE_B: 2
+
+	#Type_value: {
+		TYPE_A: 1
+		TYPE_B: 2
+	}
+
 	// A map of attribute name to its value.
 	attributes?: {
 		[string]: #AttributeValue