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https://git.proxmox.com/git/libgit2
synced 2025-05-28 19:23:05 +00:00
pack: expose a cached delta base directly
Instead of going through a special entry in the chain, let's pass it as an output parameter.
This commit is contained in:
Carlos Martín Nieto
parent
9dbd150f5f
commit
a3ffbf230e
185
src/pack.c
185
src/pack.c
@ -40,14 +40,6 @@ static int pack_entry_find_offset(
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const git_oid *short_oid,
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size_t len);
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/**
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* Generate the chain of dependencies which we need to get to the
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* object at `off`. `chain` is used a stack, popping gives the right
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* order to apply deltas on. If an object is found in the pack's base
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* cache, we stop calculating there.
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*/
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static int pack_dependency_chain(git_dependency_chain *chain, struct git_pack_file *p, git_off_t off);
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static int packfile_error(const char *message)
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{
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giterr_set(GITERR_ODB, "Invalid pack file - %s", message);
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@ -522,6 +514,87 @@ int git_packfile_resolve_header(
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return error;
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}
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/**
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* Generate the chain of dependencies which we need to get to the
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* object at `off`. `chain` is used a stack, popping gives the right
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* order to apply deltas on. If an object is found in the pack's base
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* cache, we stop calculating there.
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*/
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static int pack_dependency_chain(git_dependency_chain *chain_out, git_pack_cache_entry **cached_out,
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git_off_t *cached_off, struct git_pack_file *p, git_off_t obj_offset)
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{
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git_dependency_chain chain = GIT_ARRAY_INIT;
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git_mwindow *w_curs = NULL;
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git_off_t curpos = obj_offset, base_offset;
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int error = 0;
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size_t size;
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git_otype type;
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if (!p->bases.entries && (cache_init(&p->bases) < 0))
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return -1;
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git_array_init_to_size(chain, 64);
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while (true) {
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struct pack_chain_elem *elem;
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git_pack_cache_entry *cached = NULL;
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/* if we have a base cached, we can stop here instead */
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if ((cached = cache_get(&p->bases, obj_offset)) != NULL) {
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*cached_out = cached;
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*cached_off = obj_offset;
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break;
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}
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curpos = obj_offset;
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elem = git_array_alloc(chain);
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if (!elem) {
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error = -1;
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goto on_error;
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}
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elem->base_key = obj_offset;
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error = git_packfile_unpack_header(&size, &type, &p->mwf, &w_curs, &curpos);
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git_mwindow_close(&w_curs);
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if (error < 0)
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goto on_error;
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elem->offset = curpos;
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elem->size = size;
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elem->type = type;
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elem->base_key = obj_offset;
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if (type != GIT_OBJ_OFS_DELTA && type != GIT_OBJ_REF_DELTA)
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break;
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base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
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git_mwindow_close(&w_curs);
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if (base_offset == 0) {
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error = packfile_error("delta offset is zero");
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goto on_error;
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}
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if (base_offset < 0) { /* must actually be an error code */
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error = (int)base_offset;
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goto on_error;
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}
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/* we need to pass the pos *after* the delta-base bit */
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elem->offset = curpos;
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/* go through the loop again, but with the new object */
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obj_offset = base_offset;
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}
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*chain_out = chain;
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return error;
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on_error:
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git_array_clear(chain);
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return error;
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}
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int git_packfile_unpack(
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git_rawobj *obj,
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struct git_pack_file *p,
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@ -531,7 +604,7 @@ int git_packfile_unpack(
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git_off_t curpos = *obj_offset;
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int error, free_base = 0;
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git_dependency_chain chain = GIT_ARRAY_INIT;
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struct pack_chain_elem *elem;
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struct pack_chain_elem *elem = NULL;
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git_pack_cache_entry *cached = NULL;
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git_otype base_type;
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@ -539,7 +612,7 @@ int git_packfile_unpack(
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* TODO: optionally check the CRC on the packfile
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*/
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error = pack_dependency_chain(&chain, p, *obj_offset);
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error = pack_dependency_chain(&chain, &cached, obj_offset, p, *obj_offset);
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if (error < 0)
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return error;
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@ -547,12 +620,12 @@ int git_packfile_unpack(
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obj->len = 0;
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obj->type = GIT_OBJ_BAD;
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/* the first one is the base, so we expand that one */
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elem = git_array_pop(chain);
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base_type = elem->type;
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if (elem->cached) {
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cached = elem->cached_entry;
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if (cached) {
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memcpy(obj, &cached->raw, sizeof(git_rawobj));
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base_type = obj->type;
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} else {
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elem = git_array_pop(chain);
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base_type = elem->type;
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}
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if (error < 0)
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@ -563,10 +636,11 @@ int git_packfile_unpack(
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case GIT_OBJ_TREE:
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case GIT_OBJ_BLOB:
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case GIT_OBJ_TAG:
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if (!elem->cached) {
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if (!cached) {
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curpos = elem->offset;
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error = packfile_unpack_compressed(obj, p, &w_curs, &curpos, elem->size, elem->type);
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git_mwindow_close(&w_curs);
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base_type = elem->type;
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free_base = 1;
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}
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if (error < 0)
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@ -646,7 +720,8 @@ cleanup:
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if (error < 0)
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git__free(obj->data);
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*obj_offset = elem->offset;
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if (elem)
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*obj_offset = elem->offset;
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git_array_clear(chain);
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return error;
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@ -1240,79 +1315,3 @@ int git_pack_entry_find(
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git_oid_cpy(&e->sha1, &found_oid);
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return 0;
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}
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static int pack_dependency_chain(git_dependency_chain *chain_out, struct git_pack_file *p, git_off_t obj_offset)
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{
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git_dependency_chain chain = GIT_ARRAY_INIT;
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git_mwindow *w_curs = NULL;
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git_off_t curpos = obj_offset, base_offset;
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int error = 0;
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size_t size;
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git_otype type;
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if (!p->bases.entries && (cache_init(&p->bases) < 0))
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return -1;
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git_array_init_to_size(chain, 64);
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while (true) {
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struct pack_chain_elem *elem;
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git_pack_cache_entry *cached = NULL;
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curpos = obj_offset;
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elem = git_array_alloc(chain);
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if (!elem) {
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error = -1;
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goto on_error;
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}
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elem->base_key = obj_offset;
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/* if we have a base cached, we can stop here instead */
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if ((cached = cache_get(&p->bases, obj_offset)) != NULL) {
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elem->cached_entry = cached;
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elem->cached = 1;
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elem->type = cached->raw.type;
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break;
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}
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error = git_packfile_unpack_header(&size, &type, &p->mwf, &w_curs, &curpos);
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git_mwindow_close(&w_curs);
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if (error < 0)
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goto on_error;
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elem->cached = 0;
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elem->offset = curpos;
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elem->size = size;
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elem->type = type;
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elem->base_key = obj_offset;
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if (type != GIT_OBJ_OFS_DELTA && type != GIT_OBJ_REF_DELTA)
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break;
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base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
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git_mwindow_close(&w_curs);
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if (base_offset == 0) {
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error = packfile_error("delta offset is zero");
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goto on_error;
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}
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if (base_offset < 0) { /* must actually be an error code */
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error = (int)base_offset;
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goto on_error;
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}
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/* we need to pass the pos *after* the delta-base bit */
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elem->offset = curpos;
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/* go through the loop again, but with the new object */
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obj_offset = base_offset;
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}
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*chain_out = chain;
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return error;
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on_error:
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git_array_clear(chain);
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return error;
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}
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@ -62,14 +62,10 @@ typedef struct git_pack_cache_entry {
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} git_pack_cache_entry;
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struct pack_chain_elem {
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int cached;
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git_off_t base_key;
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/* if we don't have it cached we have this */
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git_off_t offset;
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size_t size;
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git_otype type;
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/* if cached, we have this instead */
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git_pack_cache_entry *cached_entry;
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};
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typedef git_array_t(struct pack_chain_elem) git_dependency_chain;
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