allow OFS_DELTA objects during a push

The fetching of OFS_DELTA objects has been negotiated between both peers
since git version 1.4.4.  However, this was missing from the push side
where every OFS_DELTA objects were always converted to REF_DELTA objects
causing an increase in transferred data.

To fix this, both the client and the server processes have to be
modified: the former to invoke pack-objects with --delta-base-offset
when the server provides the ofs-delta capability, and the later to send
that capability when OFS_DELTA objects are allowed as already indicated
by the repack.usedeltabaseoffset config variable which is TRUE by
default since git v1.6.0.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-receive-pack.c b/builtin-receive-pack.c
index a970b39505b5dda0bfa32a1a9c14ad676d28ec92..4b9d9218d1ea5e270e1f0cab3eab72125cab9790 100644 (file)
--- a/builtin-receive-pack.c
+++ b/builtin-receive-pack.c
@@ -27,10 +27,9 @@ static int receive_unpack_limit = -1;
 static int transfer_unpack_limit = -1;
 static int unpack_limit = 100;
 static int report_status;
+static int prefer_ofs_delta = 1;
 static const char *head_name;
-
-static char capabilities[] = " report-status delete-refs ";
-static int capabilities_sent;
+static char *capabilities_to_send;
 
 static enum deny_action parse_deny_action(const char *var, const char *value)
 {
@@ -84,24 +83,29 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
                return 0;
        }
 
+       if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
+               prefer_ofs_delta = git_config_bool(var, value);
+               return 0;
+       }
+
        return git_default_config(var, value, cb);
 }
 
 static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 {
-       if (capabilities_sent)
+       if (!capabilities_to_send)
                packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
        else
                packet_write(1, "%s %s%c%s\n",
-                            sha1_to_hex(sha1), path, 0, capabilities);
-       capabilities_sent = 1;
+                            sha1_to_hex(sha1), path, 0, capabilities_to_send);
+       capabilities_to_send = NULL;
        return 0;
 }
 
 static void write_head_info(void)
 {
        for_each_ref(show_ref, NULL);
-       if (!capabilities_sent)
+       if (capabilities_to_send)
                show_ref("capabilities^{}", null_sha1, 0, NULL);
 
 }
@@ -687,6 +691,10 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
        else if (0 <= receive_unpack_limit)
                unpack_limit = receive_unpack_limit;
 
+       capabilities_to_send = (prefer_ofs_delta) ?
+               " report-status delete-refs ofs-delta " :
+               " report-status delete-refs ";
+
        add_alternate_refs();
        write_head_info();
        clear_extra_refs();

diff --git a/builtin-send-pack.c b/builtin-send-pack.c
index d5a1c48d0e2abab16c646ce86ac9670b95dddc07..473a3de40c4cc9aab5c1355d0602646234e7bc1c 100644 (file)
--- a/builtin-send-pack.c
+++ b/builtin-send-pack.c
@@ -43,12 +43,16 @@ static int pack_objects(int fd, struct ref *refs, struct extra_have_objects *ext
                "--stdout",
                NULL,
                NULL,
+               NULL,
        };
        struct child_process po;
        int i;
 
+       i = 4;
        if (args->use_thin_pack)
-               argv[4] = "--thin";
+               argv[i++] = "--thin";
+       if (args->use_ofs_delta)
+               argv[i++] = "--delta-base-offset";
        memset(&po, 0, sizeof(po));
        po.argv = argv;
        po.in = -1;
@@ -315,6 +319,8 @@ int send_pack(struct send_pack_args *args,
                ask_for_status_report = 1;
        if (server_supports("delete-refs"))
                allow_deleting_refs = 1;
+       if (server_supports("ofs-delta"))
+               args->use_ofs_delta = 1;
 
        if (!remote_refs) {
                fprintf(stderr, "No refs in common and none specified; doing nothing.\n"

diff --git a/send-pack.h b/send-pack.h
index 83d76c7e35183ded9eec5a56c59d4da549c0b584..1d7b1b3b4f41177dfd6637fcd98a0fc01f310c09 100644 (file)
--- a/send-pack.h
+++ b/send-pack.h
@@ -6,6 +6,7 @@ struct send_pack_args {
                send_mirror:1,
                force_update:1,
                use_thin_pack:1,
+               use_ofs_delta:1,
                dry_run:1;
 };