From: Nicolas Pitre Date: Fri, 17 Oct 2008 19:57:57 +0000 (-0400) Subject: index-pack: rationalize delta resolution code X-Git-Tag: v1.6.1-rc1~94^2~4 X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=9441b61dc5;p=git.git index-pack: rationalize delta resolution code Instead of having strange loops for walking unresolved deltas with the same base duplicated in many places, let's rework the code so this is done in a single place instead. This simplifies callers quite a bit too. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano --- diff --git a/index-pack.c b/index-pack.c index d3a4d31b4..82843e7e8 100644 --- a/index-pack.c +++ b/index-pack.c @@ -244,7 +244,8 @@ static void link_base_data(struct base_data *base, struct base_data *c) c->base = base; c->child = NULL; - base_cache_used += c->size; + if (c->data) + base_cache_used += c->size; prune_base_data(c); } @@ -494,8 +495,10 @@ static void *get_base_data(struct base_data *c) free(raw); if (!c->data) bad_object(obj->idx.offset, "failed to apply delta"); - } else + } else { c->data = get_data_from_pack(obj); + c->size = obj->size; + } base_cache_used += c->size; prune_base_data(c); @@ -504,49 +507,73 @@ static void *get_base_data(struct base_data *c) } static void resolve_delta(struct object_entry *delta_obj, - struct base_data *base_obj, enum object_type type) + struct base_data *base, struct base_data *result) { void *delta_data; unsigned long delta_size; - union delta_base delta_base; - int j, first, last; - struct base_data result; - delta_obj->real_type = type; + delta_obj->real_type = base->obj->type; delta_data = get_data_from_pack(delta_obj); delta_size = delta_obj->size; - result.data = patch_delta(get_base_data(base_obj), base_obj->size, - delta_data, delta_size, - &result.size); + result->obj = delta_obj; + result->data = patch_delta(get_base_data(base), base->obj->size, + delta_data, delta_size, &result->size); free(delta_data); - if (!result.data) + if (!result->data) bad_object(delta_obj->idx.offset, "failed to apply delta"); - sha1_object(result.data, result.size, type, delta_obj->idx.sha1); + sha1_object(result->data, result->size, delta_obj->real_type, + delta_obj->idx.sha1); nr_resolved_deltas++; +} + +static void find_unresolved_deltas(struct base_data *base, + struct base_data *prev_base) +{ + int i, ref, ref_first, ref_last, ofs, ofs_first, ofs_last; + + /* + * This is a recursive function. Those brackets should help reducing + * stack usage by limiting the scope of the delta_base union. + */ + { + union delta_base base_spec; + + hashcpy(base_spec.sha1, base->obj->idx.sha1); + ref = !find_delta_children(&base_spec, &ref_first, &ref_last); + + memset(&base_spec, 0, sizeof(base_spec)); + base_spec.offset = base->obj->idx.offset; + ofs = !find_delta_children(&base_spec, &ofs_first, &ofs_last); + } + + if (!ref && !ofs) + return; - result.obj = delta_obj; - link_base_data(base_obj, &result); + link_base_data(prev_base, base); - hashcpy(delta_base.sha1, delta_obj->idx.sha1); - if (!find_delta_children(&delta_base, &first, &last)) { - for (j = first; j <= last; j++) { - struct object_entry *child = objects + deltas[j].obj_no; - if (child->real_type == OBJ_REF_DELTA) - resolve_delta(child, &result, type); + if (ref) { + for (i = ref_first; i <= ref_last; i++) { + struct object_entry *child = objects + deltas[i].obj_no; + if (child->real_type == OBJ_REF_DELTA) { + struct base_data result; + resolve_delta(child, base, &result); + find_unresolved_deltas(&result, base); + } } } - memset(&delta_base, 0, sizeof(delta_base)); - delta_base.offset = delta_obj->idx.offset; - if (!find_delta_children(&delta_base, &first, &last)) { - for (j = first; j <= last; j++) { - struct object_entry *child = objects + deltas[j].obj_no; - if (child->real_type == OBJ_OFS_DELTA) - resolve_delta(child, &result, type); + if (ofs) { + for (i = ofs_first; i <= ofs_last; i++) { + struct object_entry *child = objects + deltas[i].obj_no; + if (child->real_type == OBJ_OFS_DELTA) { + struct base_data result; + resolve_delta(child, base, &result); + find_unresolved_deltas(&result, base); + } } } - unlink_base_data(&result); + unlink_base_data(base); } static int compare_delta_entry(const void *a, const void *b) @@ -622,37 +649,13 @@ static void parse_pack_objects(unsigned char *sha1) progress = start_progress("Resolving deltas", nr_deltas); for (i = 0; i < nr_objects; i++) { struct object_entry *obj = &objects[i]; - union delta_base base; - int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last; struct base_data base_obj; if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) continue; - hashcpy(base.sha1, obj->idx.sha1); - ref = !find_delta_children(&base, &ref_first, &ref_last); - memset(&base, 0, sizeof(base)); - base.offset = obj->idx.offset; - ofs = !find_delta_children(&base, &ofs_first, &ofs_last); - if (!ref && !ofs) - continue; - base_obj.data = get_data_from_pack(obj); - base_obj.size = obj->size; base_obj.obj = obj; - link_base_data(NULL, &base_obj); - - if (ref) - for (j = ref_first; j <= ref_last; j++) { - struct object_entry *child = objects + deltas[j].obj_no; - if (child->real_type == OBJ_REF_DELTA) - resolve_delta(child, &base_obj, obj->type); - } - if (ofs) - for (j = ofs_first; j <= ofs_last; j++) { - struct object_entry *child = objects + deltas[j].obj_no; - if (child->real_type == OBJ_OFS_DELTA) - resolve_delta(child, &base_obj, obj->type); - } - unlink_base_data(&base_obj); + base_obj.data = NULL; + find_unresolved_deltas(&base_obj, NULL); display_progress(progress, nr_resolved_deltas); } } @@ -745,7 +748,6 @@ static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved) for (i = 0; i < n; i++) { struct delta_entry *d = sorted_by_pos[i]; enum object_type type; - int j, first, last; struct base_data base_obj; if (objects[d->obj_no].real_type != OBJ_REF_DELTA) @@ -759,16 +761,7 @@ static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved) die("local object %s is corrupt", sha1_to_hex(d->base.sha1)); base_obj.obj = append_obj_to_pack(f, d->base.sha1, base_obj.data, base_obj.size, type); - link_base_data(NULL, &base_obj); - - find_delta_children(&d->base, &first, &last); - for (j = first; j <= last; j++) { - struct object_entry *child = objects + deltas[j].obj_no; - if (child->real_type == OBJ_REF_DELTA) - resolve_delta(child, &base_obj, type); - } - - unlink_base_data(&base_obj); + find_unresolved_deltas(&base_obj, NULL); display_progress(progress, nr_resolved_deltas); } free(sorted_by_pos);