On 6/19/2018 10:59 AM, Duy Nguyen wrote:
On Tue, Jun 19, 2018 at 2:54 PM Derrick Stolee <stolee@xxxxxxxxx> wrote:
On 6/12/2018 11:00 AM, Duy Nguyen wrote:
On Thu, Jun 7, 2018 at 7:01 PM Derrick Stolee <stolee@xxxxxxxxx> wrote:
diff --git a/midx.c b/midx.c
index 616af66b13..3e55422a21 100644
--- a/midx.c
+++ b/midx.c
@@ -1,9 +1,62 @@
#include "git-compat-util.h"
#include "cache.h"
#include "dir.h"
+#include "csum-file.h"
+#include "lockfile.h"
#include "midx.h"
+#define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
+#define MIDX_VERSION 1
+#define MIDX_HASH_VERSION 1 /* SHA-1 */
...
+static size_t write_midx_header(struct hashfile *f,
+ unsigned char num_chunks,
+ uint32_t num_packs)
+{
+ char byte_values[4];
+ hashwrite_be32(f, MIDX_SIGNATURE);
+ byte_values[0] = MIDX_VERSION;
+ byte_values[1] = MIDX_HASH_VERSION;
Quoting from "State of NewHash work, future directions, and discussion" [1]
* If you need to serialize an algorithm identifier into your data
format, use the format_id field of struct git_hash_algo. It's
designed specifically for that purpose.
[1] https://public-inbox.org/git/20180612024252.GA141166@xxxxxxxxxxxxxxxxxxxxxxxxx/T/#m5fdd09dcaf31266c45343fb6c0beaaa3e928bc60
Thanks! I'll also use the_hash_algo->rawsz to infer the length of the
hash function.
BTW, since you're the author of commit-graph.c and may notice it has
the same problem. Don't touch that code. Brian already has some WIP
changes [1]. We just make sure new code does not add extra work for
him. I expect he'll send all those patches out soon.
[1] https://github.com/bk2204/git/commit/3f9031e06cfb21534eb7dfff7b54e7598ac1149f
Thanks for the link. It seems he is creating an oid_version() method
that returns a 1-byte version for the hash version instead of the 4-byte
signature of the_hash_algo->format_id. I look forward to incorporating
that into the MIDX format. I'll keep my macros for now, as we work out
the other details, and while Brain's patch is cooking.
Thanks,
-Stolee
