Enum support in C/C++

internal/generator/c/meta.go

@@ -29,6 +29,14 @@ import (
 	"github.com/objectbox/objectbox-generator/internal/generator/model"
 )
 
+type fbsModel struct {
+	Enums []*fbsEnum
+}
+
+func (mm *fbsModel) Merge(model *model.ModelInfo) model.ModelMeta {
+	return mm
+}
+
 type fbsObject struct {
 	*binding.Object
 	fbsObject *reflection.Object
@@ -67,33 +75,6 @@ func (mo *fbsObject) CppNamespacePrefix() string {
 	return cppNamespacePrefix(mo.Namespace)
 }
 
-// CppNamespaceStart returns c++ namespace opening declaration
-func (mo *fbsObject) CppNamespaceStart() string {
-	if len(mo.Namespace) == 0 {
-		return ""
-	}
-
-	var nss = strings.Split(mo.Namespace, ".")
-	for i, ns := range nss {
-		nss[i] = "namespace " + ns + " {"
-	}
-	return strings.Join(nss, "\n")
-}
-
-// CppNamespaceEnd returns c++ namespace closing declaration
-func (mo *fbsObject) CppNamespaceEnd() string {
-	if len(mo.Namespace) == 0 {
-		return ""
-	}
-	var result = ""
-	var nss = strings.Split(mo.Namespace, ".")
-	for _, ns := range nss {
-		// print in reversed order
-		result = "}  // namespace " + ns + "\n" + result
-	}
-	return result
-}
-
 // PreDeclareCppRelTargets returns C++ struct pre-declarations for related entities.
 func (mo *fbsObject) PreDeclareCppRelTargets() (string, error) {
 	// first create a map `(ns.entity) => bool`, then sort it to keep the code from changing, and generate the C++ decl.
@@ -140,6 +121,7 @@ func (mo *fbsObject) PreDeclareCppRelTargets() (string, error) {
 
 type fbsField struct {
 	*binding.Field
+	fbsModel *fbsModel
 	fbsField *reflection.Field
 }
 
@@ -159,6 +141,10 @@ func (mp *fbsField) CppNameRelationTarget() string {
 	return cppNamespacePrefix(mp.relTargetNamespace()) + cppName(mp.ModelProperty.RelationTarget)
 }
 
+func isEnumSupportedType(t reflection.BaseType) bool {
+	return t >= reflection.BaseTypeByte && t <= reflection.BaseTypeULong
+}
+
 // CppType returns C++ type name
 func (mp *fbsField) CppType() string {
 	var fbsType = mp.fbsField.Type(nil)
@@ -168,6 +154,8 @@ func (mp *fbsField) CppType() string {
 		cppType = cppType + "<" + fbsTypeToCppType[fbsType.Element()] + ">"
 	} else if (mp.ModelProperty.IsIdProperty() || mp.ModelProperty.Type == model.PropertyTypeRelation) && cppType == "uint64_t" {
 		cppType = "obx_id" // defined in objectbox.h
+	} else if enumIndex := fbsType.Index(); isEnumSupportedType(baseType) && enumIndex >= 0 {
+		cppType = strings.ReplaceAll(string(mp.fbsModel.Enums[enumIndex].enum.Name()), ".", "::")
 	}
 	return cppType
 }
@@ -301,3 +289,49 @@ func (mr *standaloneRel) Merge(rel *model.StandaloneRelation) model.StandaloneRe
 func (mr *standaloneRel) CppName() string {
 	return cppName(mr.ModelRelation.Name)
 }
+
+type fbsEnum struct {
+	enum   *reflection.Enum
+	Values []*reflection.EnumVal
+}
+
+func (me *fbsEnum) nameParts() (ns string, name string) {
+	var components = strings.Split(string(me.enum.Name()), ".")
+	ns = strings.Join(components[0:len(components)-1], ".")
+	name = components[len(components)-1]
+	return
+}
+
+func (me *fbsEnum) Namespace() string {
+	ns, _ := me.nameParts()
+	return ns
+}
+
+func (me *fbsEnum) Name() string {
+	_, name := me.nameParts()
+	return name
+}
+
+func (me *fbsEnum) UnderlyingCppType() string {
+	var baseType = me.enum.UnderlyingType(nil).BaseType()
+	return fbsTypeToCppType[baseType]
+}
+
+func (me *fbsEnum) Comments() []string {
+	var comments []string
+	for i := 0; i < me.enum.DocumentationLength(); i++ {
+		comments = append(comments, strings.TrimSpace(string(me.enum.Documentation(i))))
+	}
+	return comments
+}
+
+func (me *fbsEnum) HasAttribute(name string) bool {
+	var kv = reflection.KeyValue{}
+	var i = 0
+	for me.enum.Attributes(&kv, i) {
+		if string(kv.Key()) == name {
+			return true
+		}
+	}
+	return false
+}

internal/generator/c/schema-reader.go

@@ -64,6 +64,21 @@ type fbSchemaReader struct {
 // const annotationPrefix = "objectbox:"
 
 func (r *fbSchemaReader) read(schema *reflection.Schema) error {
+	var fbsmodel = &fbsModel{Enums: make([]*fbsEnum, schema.EnumsLength())}
+	r.model.Meta = fbsmodel
+	for i := range fbsmodel.Enums {
+		fbsmodel.Enums[i] = &fbsEnum{&reflection.Enum{}, []*reflection.EnumVal{}}
+		if !schema.Enums(fbsmodel.Enums[i].enum, i) {
+			return fmt.Errorf("can't access enum %d", i)
+		}
+		for j := 0; j < fbsmodel.Enums[i].enum.ValuesLength(); j++ {
+			fbsmodel.Enums[i].Values = append(fbsmodel.Enums[i].Values, &reflection.EnumVal{})
+			if !fbsmodel.Enums[i].enum.Values(fbsmodel.Enums[i].Values[j], j) {
+				return fmt.Errorf("can't access enum %s value %d", string(fbsmodel.Enums[i].enum.Name()), j)
+			}
+		}
+	}
+
 	for i := 0; i < schema.ObjectsLength(); i++ {
 		var object reflection.Object
 		if !schema.Objects(&object, i) {
@@ -132,7 +147,7 @@ func (r *fbSchemaReader) readObject(object *reflection.Object) error {
 
 func (r *fbSchemaReader) readObjectField(entity *model.Entity, field *reflection.Field) error {
 	var property = model.CreateProperty(entity, 0, 0)
-	var metaProperty = &fbsField{binding.CreateField(property), field}
+	var metaProperty = &fbsField{binding.CreateField(property), r.model.Meta.(*fbsModel), field}
 	property.Meta = metaProperty
 	metaProperty.SetName(string(field.Name()))
 

internal/generator/c/templates/binding-c.go

@@ -46,14 +46,20 @@ static void* {{.FileIdentifier}}_get_object(OBX_box* box, obx_id id, void* (*fro
 
 /// Internal function used in other generated functions to get a vTable offset for a given field.
 static flatbuffers_voffset_t {{.FileIdentifier}}_fb_field_offset(flatbuffers_voffset_t vs, const flatbuffers_voffset_t* vt, size_t field);
-
+{{range $enum := .Model.Meta.Enums}}
+typedef enum {
+	{{- range $value := $enum.Values}}
+	{{with CNamespace $enum.Namespace}}{{.}}_{{end}}{{$enum.Name}}_{{String $value.Name}} = {{$value.Value}},
+	{{- end}}
+} {{with CNamespace $enum.Namespace}}{{.}}_{{end}}{{$enum.Name}};
+{{end}}
 {{range $entity := .Model.EntitiesWithMeta}}
 {{PrintComments 0 $entity.Comments}}typedef struct {{$entity.Meta.CName}} {
 	{{range $property := $entity.Properties}}{{$propType := PropTypeName $property.Type -}}
 	{{PrintComments 1 $property.Comments}}{{if $property.Meta.FbIsVector}}{{$property.Meta.CElementType}}* {{$property.Meta.CppName}};
 	{{- if or (eq $propType "StringVector") (eq $propType "ByteVector")}}
 	size_t {{$property.Meta.CppName}}_len;{{end}}
-	{{else}}{{$property.Meta.CppType}}{{if $property.Meta.Optional}}*{{end}} {{$property.Meta.CppName}};
+	{{else}}{{CNamespace $property.Meta.CppType}}{{if $property.Meta.Optional}}*{{end}} {{$property.Meta.CppName}};
 	{{end}}{{end}}
 } {{$entity.Meta.CName}};
 

internal/generator/c/templates/binding-cpp.go

@@ -103,7 +103,7 @@ void {{$entity.Meta.CppNamespacePrefix}}{{$entity.Meta.CppName}}::_OBX_MetaInfo:
 			{{- end}};
 	}{{- else}}outObject.{{$property.Meta.CppName}}
 		{{- template "field-value-assign-pre" $property.Meta -}}
-		table->GetField<{{$property.Meta.CppFbType}}>({{- $property.FbvTableOffset}}, {{$property.Meta.FbDefaultValue}}){{if eq "bool" $property.Meta.CppType}} != 0{{end}}
+		table->GetField<{{$property.Meta.CppFbType}}>({{- $property.FbvTableOffset}}, static_cast<{{$property.Meta.CppFbType}}>({{$property.Meta.FbDefaultValue}})){{if eq "bool" $property.Meta.CppType}} != 0{{end}}
 		{{- template "field-value-assign-post" $property.Meta}};
 	{{- end}}
 	{{end}}

internal/generator/c/templates/binding-hpp.go

@@ -40,9 +40,22 @@ var CppBindingTemplateHeader = template.Must(template.New("binding-hpp").Funcs(f
 #include "flatbuffers/flatbuffers.h"
 #include "objectbox.h"
 #include "objectbox.hpp"
+{{- range $enum := .Model.Meta.Enums}}
+{{with CppNamespaceStart $enum.Namespace}}
+{{.}}{{end}}
+enum class {{$enum.Name}} : {{$enum.UnderlyingCppType}} {
+	{{- range $value := $enum.Values}}
+	{{String $value.Name}} = {{$value.Value}},
+	{{- end}}
+};
+{{- if $enum.HasAttribute "bit_flags"}}
+FLATBUFFERS_DEFINE_BITMASK_OPERATORS({{$enum.Name}}, {{$enum.UnderlyingCppType}})
+{{- end}}
+{{with CppNamespaceEnd $enum.Namespace}}{{.}}{{end -}}
+{{end}}
 {{range $entity := .Model.EntitiesWithMeta}}
 {{$entity.Meta.PreDeclareCppRelTargets -}}
-{{with $entity.Meta.CppNamespaceStart}}
+{{with CppNamespaceStart $entity.Meta.Namespace}}
 {{.}}{{end}}
 struct {{$entity.Meta.CppName}}_;
 
@@ -81,6 +94,6 @@ struct {{$entity.Meta.CppName}}_ {
 	static const obx::RelationStandalone<{{$entity.Meta.CppName}}, {{$relation.Target.Meta.CppName}}> {{$relation.Meta.CppName}};
 {{- end}}
 };
-{{with $entity.Meta.CppNamespaceEnd}}{{.}}{{end -}}
+{{with CppNamespaceEnd $entity.Meta.Namespace}}{{.}}{{end -}}
 {{end}}
 `))

internal/generator/c/templates/functions.go

@@ -93,4 +93,33 @@ var funcMap = template.FuncMap{
 	"IsOptionalPtr": func(optional string) bool {
 		return optional == "std::unique_ptr" || optional == "std::shared_ptr"
 	},
+	"CNamespace": func (ns string) string {
+		return strings.ReplaceAll(strings.ReplaceAll(ns, ".", "_"), "::", "_")
+	},
+	"CppNamespaceStart": func(ns string) string {
+		if len(ns) == 0 {
+			return ""
+		}
+
+		var nss = strings.Split(ns, ".")
+		for i, ns := range nss {
+			nss[i] = "namespace " + ns + " {"
+		}
+		return strings.Join(nss, "\n")
+	},
+	"CppNamespaceEnd": func(ns string) string {
+		if len(ns) == 0 {
+			return ""
+		}
+		var result = ""
+		var nss = strings.Split(ns, ".")
+		for _, ns := range nss {
+			// print in reversed order
+			result = "}  // namespace " + ns + "\n" + result
+		}
+		return result
+	},
+	"String": func(val []byte) string {
+		return string(val)
+	},
 }

internal/generator/merge.go

@@ -48,6 +48,12 @@ func mergeBindingWithModelInfo(currentModel *model.ModelInfo, storedModel *model
 	currentModel.LastIndexId = storedModel.LastIndexId
 	currentModel.LastRelationId = storedModel.LastRelationId
 
+	if currentModel.Meta != nil {
+		storedModel.Meta = currentModel.Meta.Merge(storedModel)
+	} else {
+		storedModel.Meta = nil
+	}
+
 	return nil
 }
 

internal/generator/model/meta.go

@@ -19,6 +19,12 @@
 
 package model
 
+// ModelMeta provides a way for bindings to provide additional information to other users of ModelInfo
+type ModelMeta interface {
+	// Merge produces new ModelMeta based on its internal state and given model
+	Merge(model *ModelInfo) ModelMeta
+}
+
 // EntityMeta provides a way for bindings to provide additional information to other users of Entity
 type EntityMeta interface {
 	// Merge produces new EntityMeta based on its internal state and given entity

internal/generator/model/model.go

@@ -62,6 +62,7 @@ type ModelInfo struct {
 
 	file *os.File   // file handle, locked while the model is open
 	Rand *rand.Rand `json:"-"` // seeded random number generator
+	Meta ModelMeta  `json:"-"`
 }
 
 var defaultModel = ModelInfo{