formats/config: Added encoder/decoder for git config files. (#97)

* WIP: Add config format parser.

* add decoder based on gcfg.

Portions of code taken from:
https://github.com/go-gcfg/gcfg/blob/5b9f94ee80b2331c3982477bd84be8edd857df33/read.go

* add git config encoder and config methods.

* use format/config in storage/filesystem for read

* use format/config in storage/filesystem to write

* formats/config: improve docs.

* formats/config: improve tests.

* formats/config: use our fork of gcfg; improve api.

* formats/config: improve api.

* storage/filesystem: fix gofmt

* formats/config: use NoSubsection constant.

* formats/config: add doc.go

* formats/config: requested sytle changes.

* formats/config: do not use *_test packages.

Author: smola

formats/config/common.go

@@ -0,0 +1,96 @@
+package config
+
+// New creates a new config instance.
+func New() *Config {
+	return &Config{}
+}
+
+type Config struct {
+	Comment  *Comment
+	Sections Sections
+	Includes Includes
+}
+
+type Includes []*Include
+
+// A reference to a included configuration.
+type Include struct {
+	Path   string
+	Config *Config
+}
+
+type Comment string
+
+const (
+	NoSubsection = ""
+)
+
+func (c *Config) Section(name string) *Section {
+	for i := len(c.Sections) - 1; i >= 0; i-- {
+		s := c.Sections[i]
+		if s.IsName(name) {
+			return s
+		}
+	}
+	s := &Section{Name: name}
+	c.Sections = append(c.Sections, s)
+	return s
+}
+
+// AddOption is a convenience method to add an option to a given
+// section and subsection.
+//
+// Use the NoSubsection constant for the subsection argument
+// if no subsection is wanted.
+func (s *Config) AddOption(section string, subsection string, key string, value string) *Config {
+	if subsection == "" {
+		s.Section(section).AddOption(key, value)
+	} else {
+		s.Section(section).Subsection(subsection).AddOption(key, value)
+	}
+
+	return s
+}
+
+// SetOption is a convenience method to set an option to a given
+// section and subsection.
+//
+// Use the NoSubsection constant for the subsection argument
+// if no subsection is wanted.
+func (s *Config) SetOption(section string, subsection string, key string, value string) *Config {
+	if subsection == "" {
+		s.Section(section).SetOption(key, value)
+	} else {
+		s.Section(section).Subsection(subsection).SetOption(key, value)
+	}
+
+	return s
+}
+
+func (c *Config) RemoveSection(name string) *Config {
+	result := Sections{}
+	for _, s := range c.Sections {
+		if !s.IsName(name) {
+			result = append(result, s)
+		}
+	}
+
+	c.Sections = result
+	return c
+}
+
+func (c *Config) RemoveSubsection(section string, subsection string) *Config {
+	for _, s := range c.Sections {
+		if s.IsName(section) {
+			result := Subsections{}
+			for _, ss := range s.Subsections {
+				if !ss.IsName(subsection) {
+					result = append(result, ss)
+				}
+			}
+			s.Subsections = result
+		}
+	}
+
+	return c
+}

formats/config/common_test.go

@@ -0,0 +1,86 @@
+package config
+
+import (
+	"testing"
+
+	. "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type CommonSuite struct{}
+
+var _ = Suite(&CommonSuite{})
+
+func (s *CommonSuite) TestConfig_SetOption(c *C) {
+	obtained := New().SetOption("section", "", "key1", "value1")
+	expected := &Config{
+		Sections: []*Section{
+			{
+				Name: "section",
+				Options: []*Option{
+					{Key: "key1", Value: "value1"},
+				},
+			},
+		},
+	}
+	c.Assert(obtained, DeepEquals, expected)
+	obtained = obtained.SetOption("section", "", "key1", "value1")
+	c.Assert(obtained, DeepEquals, expected)
+
+	obtained = New().SetOption("section", "subsection", "key1", "value1")
+	expected = &Config{
+		Sections: []*Section{
+			{
+				Name: "section",
+				Subsections: []*Subsection{
+					{
+						Name: "subsection",
+						Options: []*Option{
+							{Key: "key1", Value: "value1"},
+						},
+					},
+				},
+			},
+		},
+	}
+	c.Assert(obtained, DeepEquals, expected)
+	obtained = obtained.SetOption("section", "subsection", "key1", "value1")
+	c.Assert(obtained, DeepEquals, expected)
+}
+
+func (s *CommonSuite) TestConfig_AddOption(c *C) {
+	obtained := New().AddOption("section", "", "key1", "value1")
+	expected := &Config{
+		Sections: []*Section{
+			{
+				Name: "section",
+				Options: []*Option{
+					{Key: "key1", Value: "value1"},
+				},
+			},
+		},
+	}
+	c.Assert(obtained, DeepEquals, expected)
+}
+
+func (s *CommonSuite) TestConfig_RemoveSection(c *C) {
+	sect := New().
+		AddOption("section1", "", "key1", "value1").
+		AddOption("section2", "", "key1", "value1")
+	expected := New().
+		AddOption("section1", "", "key1", "value1")
+	c.Assert(sect.RemoveSection("other"), DeepEquals, sect)
+	c.Assert(sect.RemoveSection("section2"), DeepEquals, expected)
+}
+
+func (s *CommonSuite) TestConfig_RemoveSubsection(c *C) {
+	sect := New().
+		AddOption("section1", "sub1", "key1", "value1").
+		AddOption("section1", "sub2", "key1", "value1")
+	expected := New().
+		AddOption("section1", "sub1", "key1", "value1")
+	c.Assert(sect.RemoveSubsection("section1", "other"), DeepEquals, sect)
+	c.Assert(sect.RemoveSubsection("other", "other"), DeepEquals, sect)
+	c.Assert(sect.RemoveSubsection("section1", "sub2"), DeepEquals, expected)
+}

formats/config/decoder.go

@@ -0,0 +1,37 @@
+package config
+
+import (
+	"io"
+
+	"github.com/src-d/gcfg"
+)
+
+// A Decoder reads and decodes config files from an input stream.
+type Decoder struct {
+	io.Reader
+}
+
+// NewDecoder returns a new decoder that reads from r.
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{r}
+}
+
+// Decode reads the whole config from its input and stores it in the
+// value pointed to by config.
+func (d *Decoder) Decode(config *Config) error {
+	cb := func(s string, ss string, k string, v string, bv bool) error {
+		if ss == "" && k == "" {
+			config.Section(s)
+			return nil
+		}
+
+		if ss != "" && k == "" {
+			config.Section(s).Subsection(ss)
+			return nil
+		}
+
+		config.AddOption(s, ss, k, v)
+		return nil
+	}
+	return gcfg.ReadWithCallback(d, cb)
+}

formats/config/decoder_test.go

@@ -0,0 +1,90 @@
+package config
+
+import (
+	"bytes"
+
+	. "gopkg.in/check.v1"
+)
+
+type DecoderSuite struct{}
+
+var _ = Suite(&DecoderSuite{})
+
+func (s *DecoderSuite) TestDecode(c *C) {
+	for idx, fixture := range fixtures {
+		r := bytes.NewReader([]byte(fixture.Raw))
+		d := NewDecoder(r)
+		cfg := &Config{}
+		err := d.Decode(cfg)
+		c.Assert(err, IsNil, Commentf("decoder error for fixture: %d", idx))
+		c.Assert(cfg, DeepEquals, fixture.Config, Commentf("bad result for fixture: %d", idx))
+	}
+}
+
+func (s *DecoderSuite) TestDecodeFailsWithIdentBeforeSection(c *C) {
+	t := `
+	key=value
+	[section]
+	key=value
+	`
+	decodeFails(c, t)
+}
+
+func (s *DecoderSuite) TestDecodeFailsWithEmptySectionName(c *C) {
+	t := `
+	[]
+	key=value
+	`
+	decodeFails(c, t)
+}
+
+func (s *DecoderSuite) TestDecodeFailsWithEmptySubsectionName(c *C) {
+	t := `
+	[remote ""]
+	key=value
+	`
+	decodeFails(c, t)
+}
+
+func (s *DecoderSuite) TestDecodeFailsWithBadSubsectionName(c *C) {
+	t := `
+	[remote origin"]
+	key=value
+	`
+	decodeFails(c, t)
+	t = `
+	[remote "origin]
+	key=value
+	`
+	decodeFails(c, t)
+}
+
+func (s *DecoderSuite) TestDecodeFailsWithTrailingGarbage(c *C) {
+	t := `
+	[remote]garbage
+	key=value
+	`
+	decodeFails(c, t)
+	t = `
+	[remote "origin"]garbage
+	key=value
+	`
+	decodeFails(c, t)
+}
+
+func (s *DecoderSuite) TestDecodeFailsWithGarbage(c *C) {
+	decodeFails(c, "---")
+	decodeFails(c, "????")
+	decodeFails(c, "[sect\nkey=value")
+	decodeFails(c, "sect]\nkey=value")
+	decodeFails(c, `[section]key="value`)
+	decodeFails(c, `[section]key=value"`)
+}
+
+func decodeFails(c *C, text string) {
+	r := bytes.NewReader([]byte(text))
+	d := NewDecoder(r)
+	cfg := &Config{}
+	err := d.Decode(cfg)
+	c.Assert(err, NotNil)
+}