format/diff: unified diff encoder and public API

- Added Patch interface
- Added a Unified Diff encoder from Patches
- Added Change method to generate Patches
- Added Changes method to generate Patches
- Added Tree method to generate Patches
- Added Commit method to generate Patches

1 files changed, 54 insertions, 0 deletions

diff --git a/plumbing/object/commit_test.go b/plumbing/object/commit_test.go
index 87e80a5..e89302d 100644
--- a/plumbing/object/commit_test.go
+++ b/plumbing/object/commit_test.go
@@ -1,6 +1,7 @@
 package object
 
 import (
+	"bytes"
 	"io"
 	"strings"
 	"time"
@@ -66,6 +67,59 @@ func (s *SuiteCommit) TestParents(c *C) {
 	i.Close()
 }
 
+func (s *SuiteCommit) TestPatch(c *C) {
+	from := s.commit(c, plumbing.NewHash("918c48b83bd081e863dbe1b80f8998f058cd8294"))
+	to := s.commit(c, plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+
+	patch, err := from.Patch(to)
+	c.Assert(err, IsNil)
+
+	buf := bytes.NewBuffer(nil)
+	err = patch.Encode(buf)
+	c.Assert(err, IsNil)
+
+	c.Assert(buf.String(), Equals, `diff --git a/vendor/foo.go b/vendor/foo.go
+new file mode 100644
+index 0000000000000000000000000000000000000000..9dea2395f5403188298c1dabe8bdafe562c491e3
+--- /dev/null
++++ b/vendor/foo.go
+@@ -0,0 +1,7 @@
++package main
++
++import "fmt"
++
++func main() {
++	fmt.Println("Hello, playground")
++}
+`)
+	c.Assert(buf.String(), Equals, patch.String())
+
+	from = s.commit(c, plumbing.NewHash("b8e471f58bcbca63b07bda20e428190409c2db47"))
+	to = s.commit(c, plumbing.NewHash("35e85108805c84807bc66a02d91535e1e24b38b9"))
+
+	patch, err = from.Patch(to)
+	c.Assert(err, IsNil)
+
+	buf.Reset()
+	err = patch.Encode(buf)
+	c.Assert(err, IsNil)
+
+	c.Assert(buf.String(), Equals, `diff --git a/CHANGELOG b/CHANGELOG
+deleted file mode 100644
+index d3ff53e0564a9f87d8e84b6e28e5060e517008aa..0000000000000000000000000000000000000000
+--- a/CHANGELOG
++++ /dev/null
+@@ -1 +0,0 @@
+-Initial changelog
+diff --git a/binary.jpg b/binary.jpg
+new file mode 100644
+index 0000000000000000000000000000000000000000..d5c0f4ab811897cadf03aec358ae60d21f91c50d
+Binary files /dev/null and b/binary.jpg differ
+`)
+
+	c.Assert(buf.String(), Equals, patch.String())
+}
+
 func (s *SuiteCommit) TestCommitEncodeDecodeIdempotent(c *C) {
 	ts, err := time.Parse(time.RFC3339, "2006-01-02T15:04:05-07:00")
 	c.Assert(err, IsNil)