new plumbing package (#118)

* plumbing: now core was renamed to core, and formats and clients moved inside

12 files changed, 969 insertions, 0 deletions

diff --git a/plumbing/format/config/common.go b/plumbing/format/config/common.go
new file mode 100644
index 0000000..d2f1e5c
--- /dev/null
+++ b/plumbing/format/config/common.go
@@ -0,0 +1,97 @@
+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
+}
diff --git a/plumbing/format/config/common_test.go b/plumbing/format/config/common_test.go
new file mode 100644
index 0000000..365b53f
--- /dev/null
+++ b/plumbing/format/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", NoSubsection, "key1", "value1")
+	expected := &Config{
+		Sections: []*Section{
+			{
+				Name: "section",
+				Options: []*Option{
+					{Key: "key1", Value: "value1"},
+				},
+			},
+		},
+	}
+	c.Assert(obtained, DeepEquals, expected)
+	obtained = obtained.SetOption("section", NoSubsection, "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", NoSubsection, "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", NoSubsection, "key1", "value1").
+		AddOption("section2", NoSubsection, "key1", "value1")
+	expected := New().
+		AddOption("section1", NoSubsection, "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)
+}
diff --git a/plumbing/format/config/decoder.go b/plumbing/format/config/decoder.go
new file mode 100644
index 0000000..0f02ce1
--- /dev/null
+++ b/plumbing/format/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)
+}
diff --git a/plumbing/format/config/decoder_test.go b/plumbing/format/config/decoder_test.go
new file mode 100644
index 0000000..412549f
--- /dev/null
+++ b/plumbing/format/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)
+}
diff --git a/plumbing/format/config/doc.go b/plumbing/format/config/doc.go
new file mode 100644
index 0000000..dd77fbc
--- /dev/null
+++ b/plumbing/format/config/doc.go
@@ -0,0 +1,199 @@
+// Package config implements decoding/encoding of git config files.
+package config
+
+/*
+
+CONFIGURATION FILE
+------------------
+
+The Git configuration file contains a number of variables that affect
+the Git commands' behavior. The `.git/config` file in each repository
+is used to store the configuration for that repository, and
+`$HOME/.gitconfig` is used to store a per-user configuration as
+fallback values for the `.git/config` file. The file `/etc/gitconfig`
+can be used to store a system-wide default configuration.
+
+The configuration variables are used by both the Git plumbing
+and the porcelains. The variables are divided into sections, wherein
+the fully qualified variable name of the variable itself is the last
+dot-separated segment and the section name is everything before the last
+dot. The variable names are case-insensitive, allow only alphanumeric
+characters and `-`, and must start with an alphabetic character.  Some
+variables may appear multiple times; we say then that the variable is
+multivalued.
+
+Syntax
+~~~~~~
+
+The syntax is fairly flexible and permissive; whitespaces are mostly
+ignored.  The '#' and ';' characters begin comments to the end of line,
+blank lines are ignored.
+
+The file consists of sections and variables.  A section begins with
+the name of the section in square brackets and continues until the next
+section begins.  Section names are case-insensitive.  Only alphanumeric
+characters, `-` and `.` are allowed in section names.  Each variable
+must belong to some section, which means that there must be a section
+header before the first setting of a variable.
+
+Sections can be further divided into subsections.  To begin a subsection
+put its name in double quotes, separated by space from the section name,
+in the section header, like in the example below:
+
+--------
+	[section "subsection"]
+
+--------
+
+Subsection names are case sensitive and can contain any characters except
+newline (doublequote `"` and backslash can be included by escaping them
+as `\"` and `\\`, respectively).  Section headers cannot span multiple
+lines.  Variables may belong directly to a section or to a given subsection.
+You can have `[section]` if you have `[section "subsection"]`, but you
+don't need to.
+
+There is also a deprecated `[section.subsection]` syntax. With this
+syntax, the subsection name is converted to lower-case and is also
+compared case sensitively. These subsection names follow the same
+restrictions as section names.
+
+All the other lines (and the remainder of the line after the section
+header) are recognized as setting variables, in the form
+'name = value' (or just 'name', which is a short-hand to say that
+the variable is the boolean "true").
+The variable names are case-insensitive, allow only alphanumeric characters
+and `-`, and must start with an alphabetic character.
+
+A line that defines a value can be continued to the next line by
+ending it with a `\`; the backquote and the end-of-line are
+stripped.  Leading whitespaces after 'name =', the remainder of the
+line after the first comment character '#' or ';', and trailing
+whitespaces of the line are discarded unless they are enclosed in
+double quotes.  Internal whitespaces within the value are retained
+verbatim.
+
+Inside double quotes, double quote `"` and backslash `\` characters
+must be escaped: use `\"` for `"` and `\\` for `\`.
+
+The following escape sequences (beside `\"` and `\\`) are recognized:
+`\n` for newline character (NL), `\t` for horizontal tabulation (HT, TAB)
+and `\b` for backspace (BS).  Other char escape sequences (including octal
+escape sequences) are invalid.
+
+
+Includes
+~~~~~~~~
+
+You can include one config file from another by setting the special
+`include.path` variable to the name of the file to be included. The
+variable takes a pathname as its value, and is subject to tilde
+expansion.
+
+The
+included file is expanded immediately, as if its contents had been
+found at the location of the include directive. If the value of the
+`include.path` variable is a relative path, the path is considered to be
+relative to the configuration file in which the include directive was
+found.  See below for examples.
+
+
+Example
+~~~~~~~
+
+	# Core variables
+	[core]
+		; Don't trust file modes
+		filemode = false
+
+	# Our diff algorithm
+	[diff]
+		external = /usr/local/bin/diff-wrapper
+		renames = true
+
+	[branch "devel"]
+		remote = origin
+		merge = refs/heads/devel
+
+	# Proxy settings
+	[core]
+		gitProxy="ssh" for "kernel.org"
+		gitProxy=default-proxy ; for the rest
+
+	[include]
+		path = /path/to/foo.inc ; include by absolute path
+		path = foo ; expand "foo" relative to the current file
+		path = ~/foo ; expand "foo" in your `$HOME` directory
+
+
+Values
+~~~~~~
+
+Values of many variables are treated as a simple string, but there
+are variables that take values of specific types and there are rules
+as to how to spell them.
+
+boolean::
+
+       When a variable is said to take a boolean value, many
+       synonyms are accepted for 'true' and 'false'; these are all
+       case-insensitive.
+
+       true;; Boolean true can be spelled as `yes`, `on`, `true`,
+		or `1`.  Also, a variable defined without `= <value>`
+		is taken as true.
+
+       false;; Boolean false can be spelled as `no`, `off`,
+		`false`, or `0`.
++
+When converting value to the canonical form using `--bool` type
+specifier; 'git config' will ensure that the output is "true" or
+"false" (spelled in lowercase).
+
+integer::
+       The value for many variables that specify various sizes can
+       be suffixed with `k`, `M`,... to mean "scale the number by
+       1024", "by 1024x1024", etc.
+
+color::
+       The value for a variable that takes a color is a list of
+       colors (at most two, one for foreground and one for background)
+       and attributes (as many as you want), separated by spaces.
++
+The basic colors accepted are `normal`, `black`, `red`, `green`, `yellow`,
+`blue`, `magenta`, `cyan` and `white`.  The first color given is the
+foreground; the second is the background.
++
+Colors may also be given as numbers between 0 and 255; these use ANSI
+256-color mode (but note that not all terminals may support this).  If
+your terminal supports it, you may also specify 24-bit RGB values as
+hex, like `#ff0ab3`.
++
+
+From: https://git-scm.com/docs/git-config
+The accepted attributes are `bold`, `dim`, `ul`, `blink`, `reverse`,
+`italic`, and `strike` (for crossed-out or "strikethrough" letters).
+The position of any attributes with respect to the colors
+(before, after, or in between), doesn't matter. Specific attributes may
+be turned off by prefixing them with `no` or `no-` (e.g., `noreverse`,
+`no-ul`, etc).
++
+For git's pre-defined color slots, the attributes are meant to be reset
+at the beginning of each item in the colored output. So setting
+`color.decorate.branch` to `black` will paint that branch name in a
+plain `black`, even if the previous thing on the same output line (e.g.
+opening parenthesis before the list of branch names in `log --decorate`
+output) is set to be painted with `bold` or some other attribute.
+However, custom log formats may do more complicated and layered
+coloring, and the negated forms may be useful there.
+
+pathname::
+	A variable that takes a pathname value can be given a
+	string that begins with "`~/`" or "`~user/`", and the usual
+	tilde expansion happens to such a string: `~/`
+	is expanded to the value of `$HOME`, and `~user/` to the
+	specified user's home directory.
+
+From:
+https://raw.githubusercontent.com/git/git/659889482ac63411daea38b2c3d127842ea04e4d/Documentation/config.txt
+
+*/
diff --git a/plumbing/format/config/encoder.go b/plumbing/format/config/encoder.go
new file mode 100644
index 0000000..88bdf65
--- /dev/null
+++ b/plumbing/format/config/encoder.go
@@ -0,0 +1,75 @@
+package config
+
+import (
+	"fmt"
+	"io"
+)
+
+// An Encoder writes config files to an output stream.
+type Encoder struct {
+	w io.Writer
+}
+
+// NewEncoder returns a new encoder that writes to w.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{w}
+}
+
+// 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 err := e.encodeSection(s); err != nil {
+			return err
+		}
+	}
+
+	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/plumbing/format/config/encoder_test.go b/plumbing/format/config/encoder_test.go
new file mode 100644
index 0000000..5335b83
--- /dev/null
+++ b/plumbing/format/config/encoder_test.go
@@ -0,0 +1,21 @@
+package config
+
+import (
+	"bytes"
+
+	. "gopkg.in/check.v1"
+)
+
+type EncoderSuite struct{}
+
+var _ = Suite(&EncoderSuite{})
+
+func (s *EncoderSuite) TestEncode(c *C) {
+	for idx, fixture := range fixtures {
+		buf := &bytes.Buffer{}
+		e := NewEncoder(buf)
+		err := e.Encode(fixture.Config)
+		c.Assert(err, IsNil, Commentf("encoder error for fixture: %d", idx))
+		c.Assert(buf.String(), Equals, fixture.Text, Commentf("bad result for fixture: %d", idx))
+	}
+}
diff --git a/plumbing/format/config/fixtures_test.go b/plumbing/format/config/fixtures_test.go
new file mode 100644
index 0000000..12ff288
--- /dev/null
+++ b/plumbing/format/config/fixtures_test.go
@@ -0,0 +1,90 @@
+package config
+
+type Fixture struct {
+	Text   string
+	Raw    string
+	Config *Config
+}
+
+var fixtures = []*Fixture{
+	{
+		Raw:    "",
+		Text:   "",
+		Config: New(),
+	},
+	{
+		Raw:    ";Comments only",
+		Text:   "",
+		Config: New(),
+	},
+	{
+		Raw:    "#Comments only",
+		Text:   "",
+		Config: New(),
+	},
+	{
+		Raw:    "[core]\nrepositoryformatversion=0",
+		Text:   "[core]\n\trepositoryformatversion = 0\n",
+		Config: New().AddOption("core", "", "repositoryformatversion", "0"),
+	},
+	{
+		Raw:    "[core]\n\trepositoryformatversion = 0\n",
+		Text:   "[core]\n\trepositoryformatversion = 0\n",
+		Config: New().AddOption("core", "", "repositoryformatversion", "0"),
+	},
+	{
+		Raw:    ";Commment\n[core]\n;Comment\nrepositoryformatversion = 0\n",
+		Text:   "[core]\n\trepositoryformatversion = 0\n",
+		Config: New().AddOption("core", "", "repositoryformatversion", "0"),
+	},
+	{
+		Raw:    "#Commment\n#Comment\n[core]\n#Comment\nrepositoryformatversion = 0\n",
+		Text:   "[core]\n\trepositoryformatversion = 0\n",
+		Config: New().AddOption("core", "", "repositoryformatversion", "0"),
+	},
+	{
+		Raw: `
+			[sect1]
+			opt1 = value1
+			[sect1 "subsect1"]
+			opt2 = value2
+		`,
+		Text: `[sect1]
+	opt1 = value1
+[sect1 "subsect1"]
+	opt2 = value2
+`,
+		Config: New().
+			AddOption("sect1", "", "opt1", "value1").
+			AddOption("sect1", "subsect1", "opt2", "value2"),
+	},
+	{
+		Raw: `
+			[sect1]
+			opt1 = value1
+			[sect1 "subsect1"]
+			opt2 = value2
+			[sect1]
+			opt1 = value1b
+			[sect1 "subsect1"]
+			opt2 = value2b
+			[sect1 "subsect2"]
+			opt2 = value2
+		`,
+		Text: `[sect1]
+	opt1 = value1
+	opt1 = value1b
+[sect1 "subsect1"]
+	opt2 = value2
+	opt2 = value2b
+[sect1 "subsect2"]
+	opt2 = value2
+`,
+		Config: New().
+			AddOption("sect1", "", "opt1", "value1").
+			AddOption("sect1", "", "opt1", "value1b").
+			AddOption("sect1", "subsect1", "opt2", "value2").
+			AddOption("sect1", "subsect1", "opt2", "value2b").
+			AddOption("sect1", "subsect2", "opt2", "value2"),
+	},
+}
diff --git a/plumbing/format/config/option.go b/plumbing/format/config/option.go
new file mode 100644
index 0000000..dbb401c
--- /dev/null
+++ b/plumbing/format/config/option.go
@@ -0,0 +1,83 @@
+package config
+
+import (
+	"strings"
+)
+
+type Option struct {
+	// Key preserving original caseness.
+	// Use IsKey instead to compare key regardless of caseness.
+	Key string
+	// Original value as string, could be not notmalized.
+	Value string
+}
+
+type Options []*Option
+
+// IsKey returns true if the given key matches
+// this options' key in a case-insensitive comparison.
+func (o *Option) IsKey(key string) bool {
+	return strings.ToLower(o.Key) == strings.ToLower(key)
+}
+
+// Get gets the value for the given key if set,
+// otherwise it returns the empty string.
+//
+// Note that there is no difference
+//
+// This matches git behaviour since git v1.8.1-rc1,
+// if there are multiple definitions of a key, the
+// last one wins.
+//
+// See: http://article.gmane.org/gmane.linux.kernel/1407184
+//
+// In order to get all possible values for the same key,
+// use GetAll.
+func (opts Options) Get(key string) string {
+	for i := len(opts) - 1; i >= 0; i-- {
+		o := opts[i]
+		if o.IsKey(key) {
+			return o.Value
+		}
+	}
+	return ""
+}
+
+// GetAll returns all possible values for the same key.
+func (opts Options) GetAll(key string) []string {
+	result := []string{}
+	for _, o := range opts {
+		if o.IsKey(key) {
+			result = append(result, o.Value)
+		}
+	}
+	return result
+}
+
+func (opts Options) withoutOption(key string) Options {
+	result := Options{}
+	for _, o := range opts {
+		if !o.IsKey(key) {
+			result = append(result, o)
+		}
+	}
+	return result
+}
+
+func (opts Options) withAddedOption(key string, value string) Options {
+	return append(opts, &Option{key, value})
+}
+
+func (opts Options) withSettedOption(key string, value string) Options {
+	for i := len(opts) - 1; i >= 0; i-- {
+		o := opts[i]
+		if o.IsKey(key) {
+			result := make(Options, len(opts))
+			copy(result, opts)
+			result[i] = &Option{key, value}
+			return result
+		}
+	}
+
+	return opts.withAddedOption(key, value)
+}
diff --git a/plumbing/format/config/option_test.go b/plumbing/format/config/option_test.go
new file mode 100644
index 0000000..8588de1
--- /dev/null
+++ b/plumbing/format/config/option_test.go
@@ -0,0 +1,33 @@
+package config
+
+import (
+	. "gopkg.in/check.v1"
+)
+
+type OptionSuite struct{}
+
+var _ = Suite(&OptionSuite{})
+
+func (s *OptionSuite) TestOptions_GetAll(c *C) {
+	o := Options{
+		&Option{"k", "v"},
+		&Option{"ok", "v1"},
+		&Option{"K", "v2"},
+	}
+	c.Assert(o.GetAll("k"), DeepEquals, []string{"v", "v2"})
+	c.Assert(o.GetAll("K"), DeepEquals, []string{"v", "v2"})
+	c.Assert(o.GetAll("ok"), DeepEquals, []string{"v1"})
+	c.Assert(o.GetAll("unexistant"), DeepEquals, []string{})
+
+	o = Options{}
+	c.Assert(o.GetAll("k"), DeepEquals, []string{})
+}
+
+func (s *OptionSuite) TestOption_IsKey(c *C) {
+	c.Assert((&Option{Key: "key"}).IsKey("key"), Equals, true)
+	c.Assert((&Option{Key: "key"}).IsKey("KEY"), Equals, true)
+	c.Assert((&Option{Key: "KEY"}).IsKey("key"), Equals, true)
+	c.Assert((&Option{Key: "key"}).IsKey("other"), Equals, false)
+	c.Assert((&Option{Key: "key"}).IsKey(""), Equals, false)
+	c.Assert((&Option{Key: ""}).IsKey("key"), Equals, false)
+}
diff --git a/plumbing/format/config/section.go b/plumbing/format/config/section.go
new file mode 100644
index 0000000..1844913
--- /dev/null
+++ b/plumbing/format/config/section.go
@@ -0,0 +1,87 @@
+package config
+
+import "strings"
+
+type Section struct {
+	Name        string
+	Options     Options
+	Subsections Subsections
+}
+
+type Subsection struct {
+	Name    string
+	Options Options
+}
+
+type Sections []*Section
+
+type Subsections []*Subsection
+
+func (s *Section) IsName(name string) bool {
+	return strings.ToLower(s.Name) == strings.ToLower(name)
+}
+
+func (s *Section) Option(key string) string {
+	return s.Options.Get(key)
+}
+
+func (s *Section) AddOption(key string, value string) *Section {
+	s.Options = s.Options.withAddedOption(key, value)
+	return s
+}
+
+func (s *Section) SetOption(key string, value string) *Section {
+	s.Options = s.Options.withSettedOption(key, value)
+	return s
+}
+
+func (s *Section) RemoveOption(key string) *Section {
+	s.Options = s.Options.withoutOption(key)
+	return s
+}
+
+func (s *Section) Subsection(name string) *Subsection {
+	for i := len(s.Subsections) - 1; i >= 0; i-- {
+		ss := s.Subsections[i]
+		if ss.IsName(name) {
+			return ss
+		}
+	}
+
+	ss := &Subsection{Name: name}
+	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
+}
+
+func (s *Subsection) IsName(name string) bool {
+	return s.Name == name
+}
+
+func (s *Subsection) Option(key string) string {
+	return s.Options.Get(key)
+}
+
+func (s *Subsection) AddOption(key string, value string) *Subsection {
+	s.Options = s.Options.withAddedOption(key, value)
+	return s
+}
+
+func (s *Subsection) SetOption(key string, value string) *Subsection {
+	s.Options = s.Options.withSettedOption(key, value)
+	return s
+}
+
+func (s *Subsection) RemoveOption(key string) *Subsection {
+	s.Options = s.Options.withoutOption(key)
+	return s
+}
diff --git a/plumbing/format/config/section_test.go b/plumbing/format/config/section_test.go
new file mode 100644
index 0000000..cfd9f3f
--- /dev/null
+++ b/plumbing/format/config/section_test.go
@@ -0,0 +1,71 @@
+package config
+
+import (
+	. "gopkg.in/check.v1"
+)
+
+type SectionSuite struct{}
+
+var _ = Suite(&SectionSuite{})
+
+func (s *SectionSuite) TestSection_Option(c *C) {
+	sect := &Section{
+		Options: []*Option{
+			{Key: "key1", Value: "value1"},
+			{Key: "key2", Value: "value2"},
+			{Key: "key1", Value: "value3"},
+		},
+	}
+	c.Assert(sect.Option("otherkey"), Equals, "")
+	c.Assert(sect.Option("key2"), Equals, "value2")
+	c.Assert(sect.Option("key1"), Equals, "value3")
+}
+
+func (s *SectionSuite) TestSubsection_Option(c *C) {
+	sect := &Subsection{
+		Options: []*Option{
+			{Key: "key1", Value: "value1"},
+			{Key: "key2", Value: "value2"},
+			{Key: "key1", Value: "value3"},
+		},
+	}
+	c.Assert(sect.Option("otherkey"), Equals, "")
+	c.Assert(sect.Option("key2"), Equals, "value2")
+	c.Assert(sect.Option("key1"), Equals, "value3")
+}
+
+func (s *SectionSuite) TestSection_RemoveOption(c *C) {
+	sect := &Section{
+		Options: []*Option{
+			{Key: "key1", Value: "value1"},
+			{Key: "key2", Value: "value2"},
+			{Key: "key1", Value: "value3"},
+		},
+	}
+	c.Assert(sect.RemoveOption("otherkey"), DeepEquals, sect)
+
+	expected := &Section{
+		Options: []*Option{
+			{Key: "key2", Value: "value2"},
+		},
+	}
+	c.Assert(sect.RemoveOption("key1"), DeepEquals, expected)
+}
+
+func (s *SectionSuite) TestSubsection_RemoveOption(c *C) {
+	sect := &Subsection{
+		Options: []*Option{
+			{Key: "key1", Value: "value1"},
+			{Key: "key2", Value: "value2"},
+			{Key: "key1", Value: "value3"},
+		},
+	}
+	c.Assert(sect.RemoveOption("otherkey"), DeepEquals, sect)
+
+	expected := &Subsection{
+		Options: []*Option{
+			{Key: "key2", Value: "value2"},
+		},
+	}
+	c.Assert(sect.RemoveOption("key1"), DeepEquals, expected)
+}