move plumbing from top level package to plumbing (#183)

* plumbing: rename Object -> EncodedObject.

* plumbing/storer: rename ObjectStorer -> EncodedObjectStorer.

* move difftree to plumbing/difftree.

* move diff -> utils/diff

* make Object/Tag/Blob/Tree/Commit/File depend on storer.

* Object and its implementations now depend only on
  storer.EncodedObjectStorer, not git.Repository.
* Tests are decoupled accordingly.

* move Object/Commit/File/Tag/Tree to plumbing/object.

* move Object/Commit/File/Tag/Tree to plumbing/object.
* move checkClose to utils/ioutil.

* move RevListObjects to plumbing/revlist.Objects.

* move DiffTree to plumbing/difftree package.

* rename files with plural nouns to singular

* plumbing/object: add GetBlob/GetCommit/GetTag/GetTree.

2 files changed, 0 insertions, 154 deletions

diff --git a/diff/diff.go b/diff/diff.go
deleted file mode 100644
index b840ad6..0000000
--- a/diff/diff.go
+++ /dev/null
@@ -1,45 +0,0 @@
-// Package diff implements line oriented diffs, similar to the ancient
-// Unix diff command.
-//
-// The current implementation is just a wrapper around Sergi's
-// go-diff/diffmatchpatch library, which is a go port of Neil
-// Fraser's google-diff-match-patch code
-package diff
-
-import (
-	"bytes"
-
-	"github.com/sergi/go-diff/diffmatchpatch"
-)
-
-// Do computes the (line oriented) modifications needed to turn the src
-// string into the dst string.
-func Do(src, dst string) (diffs []diffmatchpatch.Diff) {
-	dmp := diffmatchpatch.New()
-	wSrc, wDst, warray := dmp.DiffLinesToChars(src, dst)
-	diffs = dmp.DiffMain(wSrc, wDst, false)
-	diffs = dmp.DiffCharsToLines(diffs, warray)
-	return diffs
-}
-
-// Dst computes and returns the destination text.
-func Dst(diffs []diffmatchpatch.Diff) string {
-	var text bytes.Buffer
-	for _, d := range diffs {
-		if d.Type != diffmatchpatch.DiffDelete {
-			text.WriteString(d.Text)
-		}
-	}
-	return text.String()
-}
-
-// Src computes and returns the source text
-func Src(diffs []diffmatchpatch.Diff) string {
-	var text bytes.Buffer
-	for _, d := range diffs {
-		if d.Type != diffmatchpatch.DiffInsert {
-			text.WriteString(d.Text)
-		}
-	}
-	return text.String()
-}
diff --git a/diff/diff_ext_test.go b/diff/diff_ext_test.go
deleted file mode 100644
index 484c26e..0000000
--- a/diff/diff_ext_test.go
+++ /dev/null
@@ -1,109 +0,0 @@
-package diff_test
-
-import (
-	"testing"
-
-	"gopkg.in/src-d/go-git.v4/diff"
-
-	"github.com/sergi/go-diff/diffmatchpatch"
-	. "gopkg.in/check.v1"
-)
-
-func Test(t *testing.T) { TestingT(t) }
-
-type suiteCommon struct{}
-
-var _ = Suite(&suiteCommon{})
-
-var diffTests = [...]struct {
-	src string // the src string to diff
-	dst string // the dst string to diff
-}{
-	// equal inputs
-	{"", ""},
-	{"a", "a"},
-	{"a\n", "a\n"},
-	{"a\nb", "a\nb"},
-	{"a\nb\n", "a\nb\n"},
-	{"a\nb\nc", "a\nb\nc"},
-	{"a\nb\nc\n", "a\nb\nc\n"},
-	// missing '\n'
-	{"", "\n"},
-	{"\n", ""},
-	{"a", "a\n"},
-	{"a\n", "a"},
-	{"a\nb", "a\nb"},
-	{"a\nb\n", "a\nb\n"},
-	{"a\nb\nc", "a\nb\nc"},
-	{"a\nb\nc\n", "a\nb\nc\n"},
-	// generic
-	{"a\nbbbbb\n\tccc\ndd\n\tfffffffff\n", "bbbbb\n\tccc\n\tDD\n\tffff\n"},
-}
-
-func (s *suiteCommon) TestAll(c *C) {
-	for i, t := range diffTests {
-		diffs := diff.Do(t.src, t.dst)
-		src := diff.Src(diffs)
-		dst := diff.Dst(diffs)
-		c.Assert(src, Equals, t.src, Commentf("subtest %d, src=%q, dst=%q, bad calculated src", i, t.src, t.dst))
-		c.Assert(dst, Equals, t.dst, Commentf("subtest %d, src=%q, dst=%q, bad calculated dst", i, t.src, t.dst))
-	}
-}
-
-var doTests = [...]struct {
-	src, dst string
-	exp      []diffmatchpatch.Diff
-}{
-	{
-		src: "",
-		dst: "",
-		exp: []diffmatchpatch.Diff{},
-	},
-	{
-		src: "a",
-		dst: "a",
-		exp: []diffmatchpatch.Diff{
-			{
-				Type: 0,
-				Text: "a",
-			},
-		},
-	},
-	{
-		src: "",
-		dst: "abc\ncba",
-		exp: []diffmatchpatch.Diff{
-			{
-				Type: 1,
-				Text: "abc\ncba",
-			},
-		},
-	},
-	{
-		src: "abc\ncba",
-		dst: "",
-		exp: []diffmatchpatch.Diff{
-			{
-				Type: -1,
-				Text: "abc\ncba",
-			},
-		},
-	},
-	{
-		src: "abc\nbcd\ncde",
-		dst: "000\nabc\n111\nBCD\n",
-		exp: []diffmatchpatch.Diff{
-			{Type: 1, Text: "000\n"},
-			{Type: 0, Text: "abc\n"},
-			{Type: -1, Text: "bcd\ncde"},
-			{Type: 1, Text: "111\nBCD\n"},
-		},
-	},
-}
-
-func (s *suiteCommon) TestDo(c *C) {
-	for i, t := range doTests {
-		diffs := diff.Do(t.src, t.dst)
-		c.Assert(diffs, DeepEquals, t.exp, Commentf("subtest %d", i))
-	}
-}