checkpoint (#83)

file.go

@@ -20,6 +20,10 @@ type File interface {
 	// File. Use Imports to obtain only direct dependencies.
 	TransitiveImports() []File
 
+	// UnusedImports returns all imported files that aren't used by the current
+	// File. Public imports are not included in this list.
+	UnusedImports() []File
+
 	// Dependents returns all files where the given file was directly or
 	// transitively imported.
 	Dependents() []File
@@ -125,6 +129,40 @@ func (f *file) TransitiveImports() []File {
 	return out
 }
 
+func (f *file) UnusedImports() []File {
+	public := make(map[int]struct{}, len(f.desc.PublicDependency))
+	for _, i := range f.desc.PublicDependency {
+		public[int(i)] = struct{}{}
+	}
+
+	mp := make(map[string]File, len(f.fileDependencies))
+	for i, fl := range f.fileDependencies {
+		if _, ok := public[i]; ok {
+			continue
+		}
+		mp[fl.Name().String()] = fl
+	}
+
+	for _, msg := range f.AllMessages() {
+		for _, imp := range msg.Imports() {
+			delete(mp, imp.Name().String())
+		}
+	}
+
+	for _, svc := range f.Services() {
+		for _, imp := range svc.Imports() {
+			delete(mp, imp.Name().String())
+		}
+	}
+
+	out := make([]File, 0, len(mp))
+	for _, fl := range mp {
+		out = append(out, fl)
+	}
+
+	return out
+}
+
 func (f *file) Dependents() []File {
 	if f.dependentsCache == nil {
 		set := make(map[string]File)

file_test.go

@@ -182,6 +182,48 @@ func TestFile_TransitiveImports(t *testing.T) {
 	assert.Len(t, f.TransitiveImports(), 2)
 }
 
+func TestFile_UnusedImports(t *testing.T) {
+	t.Parallel()
+
+	target := &file{desc: &descriptor.FileDescriptorProto{
+		Name: proto.String("foobar"),
+	}}
+
+	unusedFile := &file{desc: &descriptor.FileDescriptorProto{
+		Name: proto.String("i/am/unused.proto"),
+	}}
+
+	target.addFileDependency(unusedFile)
+
+	publicFile := &file{desc: &descriptor.FileDescriptorProto{
+		Name: proto.String("i/am/public.proto"),
+	}}
+
+	target.addFileDependency(publicFile)
+	target.desc.PublicDependency = append(target.desc.PublicDependency, 1)
+
+	msgDep := dummyMsg()
+	usedFile := msgDep.File().(*file)
+
+	ft := &embedT{scalarT: &scalarT{}, msg: msgDep}
+	fld := &field{}
+	fld.addType(ft)
+	m := &msg{}
+	m.addField(fld)
+	target.addMessage(m)
+
+	mtd := &method{in: msgDep, out: m}
+	svc := &service{}
+	svc.addMethod(mtd)
+	target.addService(svc)
+
+	target.addFileDependency(usedFile)
+
+	unused := target.UnusedImports()
+	assert.Len(t, unused, 1)
+	assert.Equal(t, unusedFile, unused[0])
+}
+
 func TestFile_Dependents(t *testing.T) {
 	t.Parallel()