diff options
| -rw-r--r-- | src/pack.c | 144 | ||||
| -rw-r--r-- | src/pack.h | 9 |
2 files changed, 128 insertions, 25 deletions
diff --git a/src/pack.c b/src/pack.c index b9374d04f..523905f8f 100644 --- a/src/pack.c +++ b/src/pack.c @@ -40,6 +40,13 @@ static int pack_entry_find_offset( const git_oid *short_oid, size_t len); +/** + * Generate the chain of dependencies which we need to get to the + * object at `off`. As we use a stack, the latest is the base object, + * the rest are deltas. + */ +static int pack_dependency_chain(git_dependency_chain *chain, struct git_pack_file *p, git_off_t off); + static int packfile_error(const char *message) { giterr_set(GITERR_ODB, "Invalid pack file - %s", message); @@ -583,47 +590,63 @@ int git_packfile_unpack( git_mwindow *w_curs = NULL; git_off_t curpos = *obj_offset; int error; + git_dependency_chain chain; + struct pack_chain_elem *elem; - size_t size = 0; - git_otype type; + git_otype base_type; /* * TODO: optionally check the CRC on the packfile */ + error = pack_dependency_chain(&chain, p, *obj_offset); + if (error < 0) + return error; + obj->data = NULL; obj->len = 0; obj->type = GIT_OBJ_BAD; - error = git_packfile_unpack_header(&size, &type, &p->mwf, &w_curs, &curpos); + /* the first one is the base, so we expand that one */ + elem = git_array_pop(chain); + curpos = elem->offset; + error = packfile_unpack_compressed(obj, p, &w_curs, &curpos, elem->size, elem->type); git_mwindow_close(&w_curs); if (error < 0) - return error; + goto cleanup; + + base_type = elem->type; + /* we now apply each consecutive delta until we run out */ + while (git_array_size(chain) > 0) { + git_rawobj base, delta; + + elem = git_array_pop(chain); + curpos = elem->offset; + error = packfile_unpack_compressed(&delta, p, &w_curs, &curpos, elem->size, elem->type); + git_mwindow_close(&w_curs); + + if (error < 0) + break; + + /* the current object becomes the new base, on which we apply the delta */ + base = *obj; + obj->data = NULL; + obj->len = 0; + obj->type = GIT_OBJ_BAD; + + error = git__delta_apply(obj, base.data, base.len, delta.data, delta.len); + git__free(delta.data); + git__free(base.data); + + if (error < 0) + break; - switch (type) { - case GIT_OBJ_OFS_DELTA: - case GIT_OBJ_REF_DELTA: - error = packfile_unpack_delta( - obj, p, &w_curs, &curpos, - size, type, *obj_offset); - break; - - case GIT_OBJ_COMMIT: - case GIT_OBJ_TREE: - case GIT_OBJ_BLOB: - case GIT_OBJ_TAG: - error = packfile_unpack_compressed( - obj, p, &w_curs, &curpos, - size, type); - break; - - default: - error = packfile_error("invalid packfile type in header");; - break; + obj->type = base_type; } - *obj_offset = curpos; +cleanup: + git_array_clear(chain); return error; } @@ -1215,3 +1238,74 @@ int git_pack_entry_find( git_oid_cpy(&e->sha1, &found_oid); return 0; } + +static int pack_dependency_chain(git_dependency_chain *chain_out, struct git_pack_file *p, git_off_t obj_offset) +{ + git_dependency_chain chain = GIT_ARRAY_INIT; + git_mwindow *w_curs = NULL; + git_off_t curpos = obj_offset, base_offset; + int error = 0, found_base = 0; + size_t size; + git_otype type; + + while (!found_base && error == 0) { + struct pack_chain_elem *elem; + + curpos = obj_offset; + elem = git_array_alloc(chain); + if (!elem) + return -1; + + error = git_packfile_unpack_header(&size, &type, &p->mwf, &w_curs, &curpos); + git_mwindow_close(&w_curs); + + if (error < 0) + return error; + + elem->offset = curpos; + elem->size = size; + elem->type = type; + + switch (type) { + case GIT_OBJ_OFS_DELTA: + case GIT_OBJ_REF_DELTA: + base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset); + git_mwindow_close(&w_curs); + + if (base_offset == 0) + return packfile_error("delta offset is zero"); + if (base_offset < 0) /* must actually be an error code */ + return (int)base_offset; + + /* we need to pass the pos *after* the delta-base bit */ + elem->offset = curpos; + + /* go through the loop again, but with the new object */ + obj_offset = base_offset; + break; + + /* one of these means we've found the final object in the chain */ + case GIT_OBJ_COMMIT: + case GIT_OBJ_TREE: + case GIT_OBJ_BLOB: + case GIT_OBJ_TAG: + found_base = 1; + break; + + default: + error = packfile_error("invalid packfile type in header"); + break; + } + } + + if (!found_base) { + git_array_clear(chain); + return packfile_error("after dependency chain loop; cannot happen"); + } + + if (error < 0) + git_array_clear(chain); + + *chain_out = chain; + return error; +} diff --git a/src/pack.h b/src/pack.h index 58f81e2f0..a2ea3849f 100644 --- a/src/pack.h +++ b/src/pack.h @@ -17,6 +17,7 @@ #include "mwindow.h" #include "odb.h" #include "oidmap.h" +#include "array.h" #define GIT_PACK_FILE_MODE 0444 @@ -60,6 +61,14 @@ typedef struct git_pack_cache_entry { git_rawobj raw; } git_pack_cache_entry; +struct pack_chain_elem { + git_off_t offset; + size_t size; + git_otype type; +}; + +typedef git_array_t(struct pack_chain_elem) git_dependency_chain; + #include "offmap.h" GIT__USE_OFFMAP; |