[PATCH 07/10] index-pack: learn about pack index version 2
Like previous patch but for index-pack.
[ There is quite some code duplication between pack-objects and index-pack
for generating a pack index (and fast-import as well I suppose). This
should be reworked into a common function eventually. But not now. ]
Signed-off-by: Nicolas Pitre <nico@cam.org>
---
index-pack.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 57 insertions(+), 9 deletions(-)
diff --git a/index-pack.c b/index-pack.c
index d33f723..a833f64 100644
--- a/index-pack.c
+++ b/index-pack.c
@@ -686,9 +686,10 @@ static const char *write_index_file(const char *index_name, unsigned char *sha1)
{
struct sha1file *f;
struct object_entry **sorted_by_sha, **list, **last;
- unsigned int array[256];
+ uint32_t array[256];
int i, fd;
SHA_CTX ctx;
+ uint32_t index_version;
if (nr_objects) {
sorted_by_sha =
@@ -699,7 +700,6 @@ static const char *write_index_file(const char *index_name, unsigned char *sha1)
sorted_by_sha[i] = &objects[i];
qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
sha1_compare);
-
}
else
sorted_by_sha = list = last = NULL;
@@ -718,6 +718,17 @@ static const char *write_index_file(const char *index_name, unsigned char *sha1)
die("unable to create %s: %s", index_name, strerror(errno));
f = sha1fd(fd, index_name);
+ /* if last object's offset is >= 2^31 we should use index V2 */
+ index_version = (objects[nr_objects-1].offset >> 31) ? 2 : 1;
+
+ /* index versions 2 and above need a header */
+ if (index_version >= 2) {
+ struct pack_idx_header hdr;
+ hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
+ hdr.idx_version = htonl(index_version);
+ sha1write(f, &hdr, sizeof(hdr));
+ }
+
/*
* Write the first-level table (the list is sorted,
* but we use a 256-entry lookup to be able to avoid
@@ -734,24 +745,61 @@ static const char *write_index_file(const char *index_name, unsigned char *sha1)
array[i] = htonl(next - sorted_by_sha);
list = next;
}
- sha1write(f, array, 256 * sizeof(int));
+ sha1write(f, array, 256 * 4);
- /* recompute the SHA1 hash of sorted object names.
- * currently pack-objects does not do this, but that
- * can be fixed.
- */
+ /* compute the SHA1 hash of sorted object names. */
SHA1_Init(&ctx);
+
/*
* Write the actual SHA1 entries..
*/
list = sorted_by_sha;
for (i = 0; i < nr_objects; i++) {
struct object_entry *obj = *list++;
- unsigned int offset = htonl(obj->offset);
- sha1write(f, &offset, 4);
+ if (index_version < 2) {
+ uint32_t offset = htonl(obj->offset);
+ sha1write(f, &offset, 4);
+ }
sha1write(f, obj->sha1, 20);
SHA1_Update(&ctx, obj->sha1, 20);
}
+
+ if (index_version >= 2) {
+ unsigned int nr_large_offset = 0;
+
+ /* write the crc32 table */
+ list = sorted_by_sha;
+ for (i = 0; i < nr_objects; i++) {
+ struct object_entry *obj = *list++;
+ uint32_t crc32_val = htonl(obj->crc32);
+ sha1write(f, &crc32_val, 4);
+ }
+
+ /* write the 32-bit offset table */
+ list = sorted_by_sha;
+ for (i = 0; i < nr_objects; i++) {
+ struct object_entry *obj = *list++;
+ uint32_t offset = (obj->offset <= 0x7fffffff) ?
+ obj->offset : (0x80000000 | nr_large_offset++);
+ offset = htonl(offset);
+ sha1write(f, &offset, 4);
+ }
+
+ /* write the large offset table */
+ list = sorted_by_sha;
+ while (nr_large_offset) {
+ struct object_entry *obj = *list++;
+ uint64_t offset = obj->offset;
+ if (offset > 0x7fffffff) {
+ uint32_t split[2];
+ split[0] = htonl(offset >> 32);
+ split[1] = htonl(offset & 0xffffffff);
+ sha1write(f, split, 8);
+ nr_large_offset--;
+ }
+ }
+ }
+
sha1write(f, sha1, 20);
sha1close(f, NULL, 1);
free(sorted_by_sha);
--
1.5.1.696.g6d352-dirty
Nicolas Pitre <nico@cam.org>