section: add ChildSections (#95)

Also added (*File).ChildSecions.

ini.go

@@ -37,7 +37,7 @@ const (
 
 	// Maximum allowed depth when recursively substituing variable names.
 	_DEPTH_VALUES = 99
-	_VERSION      = "1.26.0"
+	_VERSION      = "1.27.0"
 )
 
 // Version returns current package version literal.
@@ -321,6 +321,11 @@ func (f *File) Sections() []*Section {
 	return sections
 }
 
+// ChildSections returns a list of child sections of given section name.
+func (f *File) ChildSections(name string) []*Section {
+	return f.Section(name).ChildSections()
+}
+
 // SectionStrings returns list of section names.
 func (f *File) SectionStrings() []string {
 	list := make([]string, len(f.sectionList))

ini_test.go

@@ -241,6 +241,31 @@ key5
 	})
 }
 
+func Test_File_ChildSections(t *testing.T) {
+	Convey("Find child sections by parent name", t, func() {
+		cfg, err := Load([]byte(`
+[node]
+
+[node.biz1]
+
+[node.biz2]
+
+[node.biz3]
+
+[node.bizN]
+`))
+		So(err, ShouldBeNil)
+		So(cfg, ShouldNotBeNil)
+
+		children := cfg.ChildSections("node")
+		names := make([]string, len(children))
+		for i := range children {
+			names[i] = children[i].name
+		}
+		So(strings.Join(names, ","), ShouldEqual, "node.biz1,node.biz2,node.biz3,node.bizN")
+	})
+}
+
 func Test_LooseLoad(t *testing.T) {
 	Convey("Loose load from data sources", t, func() {
 		Convey("Loose load mixed with nonexistent file", func() {

section.go

@@ -232,3 +232,17 @@ func (s *Section) DeleteKey(name string) {
 		}
 	}
 }
+
+// ChildSections returns a list of child sections of current section.
+// For example, "[parent.child1]" and "[parent.child12]" are child sections
+// of section "[parent]".
+func (s *Section) ChildSections() []*Section {
+	prefix := s.name + "."
+	children := make([]*Section, 0, 3)
+	for _, name := range s.f.sectionList {
+		if strings.HasPrefix(name, prefix) {
+			children = append(children, s.f.sections[name])
+		}
+	}
+	return children
+}