storage/filesystem: implement missing functionality. (#110)

* storage/filesystem: added ObjectStorage Set.
* storage/filesystem: now passes all tests, except those specific to transactions.
* formats/config: Encoder now encodes subsections with no options.
* formats/config: add HasSubsection on Section.
* dotgit: add Ref method to get specific reference.

3 files changed, 67 insertions, 20 deletions

diff --git a/formats/config/common_test.go b/formats/config/common_test.go
index 0bc4d2d..365b53f 100644
--- a/formats/config/common_test.go
+++ b/formats/config/common_test.go
@@ -13,7 +13,7 @@ type CommonSuite struct{}
 var _ = Suite(&CommonSuite{})
 
 func (s *CommonSuite) TestConfig_SetOption(c *C) {
-	obtained := New().SetOption("section", "", "key1", "value1")
+	obtained := New().SetOption("section", NoSubsection, "key1", "value1")
 	expected := &Config{
 		Sections: []*Section{
 			{
@@ -25,7 +25,7 @@ func (s *CommonSuite) TestConfig_SetOption(c *C) {
 		},
 	}
 	c.Assert(obtained, DeepEquals, expected)
-	obtained = obtained.SetOption("section", "", "key1", "value1")
+	obtained = obtained.SetOption("section", NoSubsection, "key1", "value1")
 	c.Assert(obtained, DeepEquals, expected)
 
 	obtained = New().SetOption("section", "subsection", "key1", "value1")
@@ -50,7 +50,7 @@ func (s *CommonSuite) TestConfig_SetOption(c *C) {
 }
 
 func (s *CommonSuite) TestConfig_AddOption(c *C) {
-	obtained := New().AddOption("section", "", "key1", "value1")
+	obtained := New().AddOption("section", NoSubsection, "key1", "value1")
 	expected := &Config{
 		Sections: []*Section{
 			{
@@ -66,10 +66,10 @@ func (s *CommonSuite) TestConfig_AddOption(c *C) {
 
 func (s *CommonSuite) TestConfig_RemoveSection(c *C) {
 	sect := New().
-		AddOption("section1", "", "key1", "value1").
-		AddOption("section2", "", "key1", "value1")
+		AddOption("section1", NoSubsection, "key1", "value1").
+		AddOption("section2", NoSubsection, "key1", "value1")
 	expected := New().
-		AddOption("section1", "", "key1", "value1")
+		AddOption("section1", NoSubsection, "key1", "value1")
 	c.Assert(sect.RemoveSection("other"), DeepEquals, sect)
 	c.Assert(sect.RemoveSection("section2"), DeepEquals, expected)
 }
diff --git a/formats/config/encoder.go b/formats/config/encoder.go
index 4a68e44..88bdf65 100644
--- a/formats/config/encoder.go
+++ b/formats/config/encoder.go
@@ -7,7 +7,7 @@ import (
 
 // An Encoder writes config files to an output stream.
 type Encoder struct {
-	io.Writer
+	w io.Writer
 }
 
 // NewEncoder returns a new encoder that writes to w.
@@ -18,21 +18,58 @@ func NewEncoder(w io.Writer) *Encoder {
 // Encode writes the config in git config format to the stream of the encoder.
 func (e *Encoder) Encode(cfg *Config) error {
 	for _, s := range cfg.Sections {
-		if len(s.Options) > 0 {
-			fmt.Fprintf(e, "[%s]\n", s.Name)
-			for _, o := range s.Options {
-				fmt.Fprintf(e, "\t%s = %s\n", o.Key, o.Value)
-			}
+		if err := e.encodeSection(s); err != nil {
+			return err
 		}
-		for _, ss := range s.Subsections {
-			if len(ss.Options) > 0 {
-				//TODO: escape
-				fmt.Fprintf(e, "[%s \"%s\"]\n", s.Name, ss.Name)
-				for _, o := range ss.Options {
-					fmt.Fprintf(e, "\t%s = %s\n", o.Key, o.Value)
-				}
-			}
+	}
+
+	return nil
+}
+
+func (e *Encoder) encodeSection(s *Section) error {
+	if len(s.Options) > 0 {
+		if err := e.printf("[%s]\n", s.Name); err != nil {
+			return err
+		}
+
+		if err := e.encodeOptions(s.Options); err != nil {
+			return err
+		}
+	}
+
+	for _, ss := range s.Subsections {
+		if err := e.encodeSubsection(s.Name, ss); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (e *Encoder) encodeSubsection(sectionName string, s *Subsection) error {
+	//TODO: escape
+	if err := e.printf("[%s \"%s\"]\n", sectionName, s.Name); err != nil {
+		return err
+	}
+
+	if err := e.encodeOptions(s.Options); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (e *Encoder) encodeOptions(opts Options) error {
+	for _, o := range opts {
+		if err := e.printf("\t%s = %s\n", o.Key, o.Value); err != nil {
+			return err
 		}
 	}
+
 	return nil
 }
+
+func (e *Encoder) printf(msg string, args ...interface{}) error {
+	_, err := fmt.Fprintf(e.w, msg, args...)
+	return err
+}
diff --git a/formats/config/section.go b/formats/config/section.go
index 6d6a891..552ce74 100644
--- a/formats/config/section.go
+++ b/formats/config/section.go
@@ -74,3 +74,13 @@ func (s *Section) Subsection(name string) *Subsection {
 	s.Subsections = append(s.Subsections, ss)
 	return ss
 }
+
+func (s *Section) HasSubsection(name string) bool {
+	for _, ss := range s.Subsections {
+		if ss.IsName(name) {
+			return true
+		}
+	}
+
+	return false
+}