From d2a9d7768bb76719ac4506715ec8037fea3609a2 Mon Sep 17 00:00:00 2001
From: Quinn Slack <qslack@qslack.com>
Date: Tue, 30 Dec 2014 02:03:20 -0800
Subject: [PATCH] heed DiffOptions fields OldPrefix and NewPrefix

---
 diff.go      |  6 ++++++
 diff_test.go | 19 +++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/diff.go b/diff.go
index 999f067..63f3453 100644
--- a/diff.go
+++ b/diff.go
@@ -371,6 +371,8 @@ func DefaultDiffOptions() (DiffOptions, error) {
 		InterhunkLines:   uint32(opts.interhunk_lines),
 		IdAbbrev:         uint16(opts.id_abbrev),
 		MaxSize:          int(opts.max_size),
+		OldPrefix:        "a",
+		NewPrefix:        "b",
 	}, nil
 }
 
@@ -479,6 +481,8 @@ func diffOptionsToC(opts *DiffOptions) (copts *C.git_diff_options, notifyData *d
 			interhunk_lines:   C.uint32_t(opts.InterhunkLines),
 			id_abbrev:         C.uint16_t(opts.IdAbbrev),
 			max_size:          C.git_off_t(opts.MaxSize),
+			old_prefix:        C.CString(opts.OldPrefix),
+			new_prefix:        C.CString(opts.NewPrefix),
 		}
 
 		if opts.NotifyCallback != nil {
@@ -493,6 +497,8 @@ func freeDiffOptions(copts *C.git_diff_options) {
 	if copts != nil {
 		cpathspec := copts.pathspec
 		freeStrarray(&cpathspec)
+		C.free(unsafe.Pointer(copts.old_prefix))
+		C.free(unsafe.Pointer(copts.new_prefix))
 	}
 }
 
diff --git a/diff_test.go b/diff_test.go
index 84d72db..7c54f4e 100644
--- a/diff_test.go
+++ b/diff_test.go
@@ -3,6 +3,7 @@ package git
 import (
 	"errors"
 	"os"
+	"strings"
 	"testing"
 )
 
@@ -75,6 +76,8 @@ func TestDiffTreeToTree(t *testing.T) {
 			callbackInvoked = true
 			return nil
 		},
+		OldPrefix: "x1/",
+		NewPrefix: "y1/",
 	}
 
 	diff, err := repo.DiffTreeToTree(originalTree, newTree, &opts)
@@ -90,7 +93,19 @@ func TestDiffTreeToTree(t *testing.T) {
 	files := make([]string, 0)
 	hunks := make([]DiffHunk, 0)
 	lines := make([]DiffLine, 0)
+	patches := make([]string, 0)
 	err = diff.ForEach(func(file DiffDelta, progress float64) (DiffForEachHunkCallback, error) {
+		patch, err := diff.Patch(len(patches))
+		if err != nil {
+			return nil, err
+		}
+		defer patch.Free()
+		patchStr, err := patch.String()
+		if err != nil {
+			return nil, err
+		}
+		patches = append(patches, patchStr)
+
 		files = append(files, file.OldFile.Path)
 		return func(hunk DiffHunk) (DiffForEachLineCallback, error) {
 			hunks = append(hunks, hunk)
@@ -131,6 +146,10 @@ func TestDiffTreeToTree(t *testing.T) {
 		t.Fatal("Incorrect lines in diff")
 	}
 
+	if want1, want2 := "x1/README", "y1/README"; !strings.Contains(patches[0], want1) || !strings.Contains(patches[0], want2) {
+		t.Errorf("Diff patch doesn't contain %q or %q\n\n%s", want1, want2, patches[0])
+	}
+
 	errTest := errors.New("test error")
 
 	err = diff.ForEach(func(file DiffDelta, progress float64) (DiffForEachHunkCallback, error) {