From bee1068871f6f9bcf66c5559166290ce5eb8c311 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlos=20Mart=C3=ADn=20Nieto?= <cmn@dwim.me>
Date: Tue, 18 Jun 2019 11:33:28 +0200
Subject: [PATCH] Merge pull request #512 from codeocean/diff-to-buf

Add Diff.ToBuf wrapping git_diff_to_buf

(cherry picked from commit 4fa93499429f056b0d7c6e2634b9f17d29df96b3)
---
 diff.go | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/diff.go b/diff.go
index 3088320..eb893ce 100644
--- a/diff.go
+++ b/diff.go
@@ -405,6 +405,36 @@ func (diff *Diff) Patch(deltaIndex int) (*Patch, error) {
 	return newPatchFromC(patchPtr), nil
 }
 
+type DiffFormat int
+
+const (
+	DiffFormatPatch       DiffFormat = C.GIT_DIFF_FORMAT_PATCH
+	DiffFormatPatchHeader DiffFormat = C.GIT_DIFF_FORMAT_PATCH_HEADER
+	DiffFormatRaw         DiffFormat = C.GIT_DIFF_FORMAT_RAW
+	DiffFormatNameOnly    DiffFormat = C.GIT_DIFF_FORMAT_NAME_ONLY
+	DiffFormatNameStatus  DiffFormat = C.GIT_DIFF_FORMAT_NAME_STATUS
+)
+
+func (diff *Diff) ToBuf(format DiffFormat) ([]byte, error) {
+	if diff.ptr == nil {
+		return nil, ErrInvalid
+	}
+
+	diffBuf := C.git_buf{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_diff_to_buf(&diffBuf, diff.ptr, C.git_diff_format_t(format))
+	runtime.KeepAlive(diff)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+	defer C.git_buf_free(&diffBuf)
+
+	return C.GoBytes(unsafe.Pointer(diffBuf.ptr), C.int(diffBuf.size)), nil
+}
+
 type DiffOptionsFlag int
 
 const (