[PATCH 7/9] pv4_tree_desc: don't bother looking for v4 trees if no v4 packs are present

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

This is mostly to avoid overhead on v2 only systems.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 packv4-parse.c | 5 ++++-
 sha1_file.c    | 5 +++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/packv4-parse.c b/packv4-parse.c
index 7d257af..4354ee3 100644
--- a/packv4-parse.c
+++ b/packv4-parse.c
@@ -12,6 +12,8 @@
 #include "packv4-parse.h"
 #include "varint.h"
 
+int packv4_available;
+
 const unsigned char *get_sha1ref(struct packed_git *p,
 				 const unsigned char **bufp)
 {
@@ -749,7 +751,8 @@ int pv4_tree_desc_from_sha1(struct pv4_tree_desc *desc,
 	strbuf_init(&desc->buf, 0);
 
 	memset(&oi, 0, sizeof(oi));
-	if (!sha1_object_info_extended(sha1, &oi) &&
+	if (packv4_available &&
+	    !sha1_object_info_extended(sha1, &oi) &&
 	    oi.whence == OI_PACKED &&
 	    oi.u.packed.real_type == OBJ_PV4_TREE &&
 	    oi.u.packed.pack->version >= 4) {
diff --git a/sha1_file.c b/sha1_file.c
index 5848008..4744132 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -40,6 +40,7 @@ const unsigned char null_sha1[20];
 
 static const char *no_log_pack_access = "no_log_pack_access";
 static const char *log_pack_access;
+extern int packv4_available;
 
 /*
  * This is meant to hold a *small* number of objects that you would
@@ -763,6 +764,8 @@ void free_pack_by_name(const char *pack_name)
 				close(p->pack_fd);
 				pack_open_fds--;
 			}
+			if (p->version >= 4)
+				packv4_available--;
 			close_pack_index(p);
 			free(p->bad_object_sha1);
 			pv4_free_dict(p->ident_dict);
@@ -856,6 +859,8 @@ static int open_packed_git_1(struct packed_git *p)
 			" supported (try upgrading GIT to a newer version)",
 			p->pack_name, ntohl(hdr.hdr_version));
 	p->version = ntohl(hdr.hdr_version);
+	if (p->version >= 4)
+		packv4_available++;
 
 	/* Verify the pack matches its index. */
 	if (p->num_objects != ntohl(hdr.hdr_entries))
-- 
1.8.2.83.gc99314b