From 61acc9fadebe895439a19b63074da03ed65b9bd8 Mon Sep 17 00:00:00 2001
From: Gaurav Saral <gsaral@microsoft.com>
Date: Wed, 8 Feb 2017 16:22:44 +0530
Subject: [PATCH] Changes to provide option to turn off/on ofs_delta

This change provides an option in git_libgit2_opt_t which can be used in git_libgit2_opts to turn off/on ofs_delta capability in libGit2
---
 include/git2/common.h           | 11 +++++++++++
 src/settings.c                  |  5 +++++
 src/transports/smart.h          |  2 ++
 src/transports/smart_protocol.c |  4 +++-
 4 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/include/git2/common.h b/include/git2/common.h
index 5be7fb632..f13dfd509 100644
--- a/include/git2/common.h
+++ b/include/git2/common.h
@@ -178,6 +178,7 @@ typedef enum {
 	GIT_OPT_ENABLE_STRICT_SYMBOLIC_REF_CREATION,
 	GIT_OPT_SET_SSL_CIPHERS,
 	GIT_OPT_GET_USER_AGENT,
+	GIT_OPT_ENABLE_OFS_DELTA,
 } git_libgit2_opt_t;
 
 /**
@@ -305,6 +306,16 @@ typedef enum {
  *		>
  *		> - `ciphers` is the list of ciphers that are eanbled.
  *
+ *	* opts(GIT_OPT_ENABLE_OFS_DELTA, int enabled)
+ *
+ *		> Enable or disable the use of "offset deltas" when creating packfiles,
+ *		> and the negotiation of them when talking to a remote server.
+ *		> Offset deltas store a delta base location as an offset into the
+ *		> packfile from the current location, which provides a shorter encoding
+ *		> and thus smaller resultant packfiles.
+ *		> Packfiles containing offset deltas can still be read.
+ *		> This defaults to enabled.
+ *
  * @param option Option key
  * @param ... value to set the option
  * @return 0 on success, <0 on failure
diff --git a/src/settings.c b/src/settings.c
index 222bd6b8e..21585672c 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -16,6 +16,7 @@
 #include "global.h"
 #include "object.h"
 #include "refs.h"
+#include "transports/smart.h"
 
 void git_libgit2_version(int *major, int *minor, int *rev)
 {
@@ -222,6 +223,10 @@ int git_libgit2_opts(int key, ...)
 		}
 		break;
 
+	case GIT_OPT_ENABLE_OFS_DELTA:
+		git_smart__ofs_delta_enabled = (va_arg(ap, int) != 0);
+		break;
+
 	default:
 		giterr_set(GITERR_INVALID, "invalid option key");
 		error = -1;
diff --git a/src/transports/smart.h b/src/transports/smart.h
index 0a0c3fc1b..b47001fe0 100644
--- a/src/transports/smart.h
+++ b/src/transports/smart.h
@@ -26,6 +26,8 @@
 #define GIT_CAP_THIN_PACK "thin-pack"
 #define GIT_CAP_SYMREF "symref"
 
+extern bool git_smart__ofs_delta_enabled;
+
 enum git_pkt_type {
 	GIT_PKT_CMD,
 	GIT_PKT_FLUSH,
diff --git a/src/transports/smart_protocol.c b/src/transports/smart_protocol.c
index 7a1d4dc14..25e78c65a 100644
--- a/src/transports/smart_protocol.c
+++ b/src/transports/smart_protocol.c
@@ -19,6 +19,8 @@
 /* The minimal interval between progress updates (in seconds). */
 #define MIN_PROGRESS_UPDATE_INTERVAL 0.5
 
+bool git_smart__ofs_delta_enabled = true;
+
 int git_smart__store_refs(transport_smart *t, int flushes)
 {
 	gitno_buffer *buf = &t->buffer;
@@ -138,7 +140,7 @@ int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps, git_vec
 		if (*ptr == ' ')
 			ptr++;
 
-		if (!git__prefixcmp(ptr, GIT_CAP_OFS_DELTA)) {
+		if (git_smart__ofs_delta_enabled && !git__prefixcmp(ptr, GIT_CAP_OFS_DELTA)) {
 			caps->common = caps->ofs_delta = 1;
 			ptr += strlen(GIT_CAP_OFS_DELTA);
 			continue;