On Sat, 7 Sep 2013, Nguyễn Thái Ngọc Duy wrote:
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclo...@gmail.com>
> ---
> builtin/index-pack.c | 104
> +++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 100 insertions(+), 4 deletions(-)
>
> diff --git a/builtin/index-pack.c b/builtin/index-pack.c
> index 210b78d..51ca64b 100644
> --- a/builtin/index-pack.c
> +++ b/builtin/index-pack.c
> @@ -319,6 +319,21 @@ static const unsigned char *read_sha1ref(void)
> return sha1_table + index * 20;
> }
>
> +static const unsigned char *read_sha1table_ref(void)
> +{
> + const unsigned char *sha1 = read_sha1ref();
> + if (sha1 < sha1_table || sha1 >= sha1_table + nr_objects * 20) {
> + unsigned char *found;
> + found = bsearch(sha1, sha1_table, nr_objects, 20,
> + (int (*)(const void *, const void *))hashcmp);
> + if (!found)
> + bad_object(consumed_bytes,
> + _("SHA-1 %s not found in SHA-1 table"),
> + sha1_to_hex(sha1));
> + }
> + return sha1;
> +}
> +
> static const unsigned char *read_dictref(struct packv4_dict *dict)
> {
> unsigned int index = read_varint();
> @@ -561,17 +576,93 @@ static void *unpack_commit_v4(unsigned int offset,
> return dst.buf;
> }
>
> -static void *unpack_entry_data(unsigned long offset, unsigned long size,
> - enum object_type type, unsigned char *sha1)
> +/*
> + * v4 trees are actually kind of deltas and we don't do delta in the
> + * first pass. This function only walks through a tree object to find
> + * the end offset, register object dependencies and performs limited
> + * validation.
> + */
> +static void *unpack_tree_v4(struct object_entry *obj,
> + unsigned int offset, unsigned long size,
> + unsigned char *sha1)
> +{
> + unsigned int nr = read_varint();
> + const unsigned char *last_base = NULL;
> + struct strbuf sb = STRBUF_INIT;
> + while (nr) {
> + unsigned int copy_start_or_path = read_varint();
> + if (copy_start_or_path & 1) { /* copy_start */
> + unsigned int copy_count = read_varint();
> + if (copy_count & 1) { /* first delta */
> + last_base = read_sha1table_ref();
> + } else if (!last_base)
> + bad_object(offset,
> + _("bad copy count index in
> unpack_tree_v4"));
Here the error message could be a little more explicit i.e. "missing
delta base" or the like in order to distinguish from the next error.
> + copy_count >>= 1;
> + if (!copy_count)
> + bad_object(offset,
> + _("bad copy count index in
> unpack_tree_v4"));
> + nr -= copy_count;
Also make sure copy_count <= nr here.
> + } else { /* path */
> + unsigned int path_idx = copy_start_or_path >> 1;
> + const unsigned char *entry_sha1;
> +
> + if (path_idx >= path_dict->nb_entries)
> + bad_object(offset,
> + _("bad path index in
> unpack_tree_v4"));
> + entry_sha1 = read_sha1ref();
> + nr--;
> +
> + if (!last_base) {
I've been confused for a while here by the use of last_base in the non
delta path. A comment indicating why this used here might be helpful to
those unfamiliar with the format.
> + const unsigned char *path;
> + unsigned mode;
> +
> + path = path_dict->data +
> path_dict->offsets[path_idx];
> + mode = (path[0] << 8) | path[1];
> + strbuf_addf(&sb, "%o %s%c", mode, path+2, '\0');
> + strbuf_add(&sb, entry_sha1, 20);
> + if (sb.len > size)
> + bad_object(offset,
> + _("tree larger than
> expected"));
> + }
> + }
> + }
> +
> + if (last_base) {
> + strbuf_release(&sb);
> + return NULL;
> + } else {
> + git_SHA_CTX ctx;
> + char hdr[32];
> + int hdrlen;
> +
> + if (sb.len != size)
> + bad_object(offset, _("tree size mismatch"));
> +
> + hdrlen = sprintf(hdr, "tree %lu", size) + 1;
> + git_SHA1_Init(&ctx);
> + git_SHA1_Update(&ctx, hdr, hdrlen);
> + git_SHA1_Update(&ctx, sb.buf, size);
> + git_SHA1_Final(sha1, &ctx);
> + return strbuf_detach(&sb, NULL);
> + }
> +}
> +
> +static void *unpack_entry_data(struct object_entry *obj, unsigned char *sha1)
> {
> static char fixed_buf[8192];
> void *buf;
> git_SHA_CTX c;
> char hdr[32];
> int hdrlen;
> + unsigned long offset = obj->idx.offset;
> + unsigned long size = obj->size;
> + enum object_type type = obj->type;
>
> if (type == OBJ_PV4_COMMIT)
> return unpack_commit_v4(offset, size, sha1);
> + if (type == OBJ_PV4_TREE)
> + return unpack_tree_v4(obj, offset, size, sha1);
>
> if (!is_delta_type(type)) {
> hdrlen = sprintf(hdr, "%s %lu", typename(type), size) + 1;
> @@ -640,16 +731,19 @@ static void *unpack_raw_entry(struct object_entry *obj,
> case OBJ_BLOB:
> case OBJ_TAG:
> break;
> -
> case OBJ_PV4_COMMIT:
> obj->real_type = OBJ_COMMIT;
> break;
> + case OBJ_PV4_TREE:
> + obj->real_type = OBJ_TREE;
> + break;
> +
> default:
> bad_object(obj->idx.offset, _("unknown object type %d"),
> obj->type);
> }
> obj->hdr_size = consumed_bytes - obj->idx.offset;
>
> - data = unpack_entry_data(obj->idx.offset, obj->size, obj->type, sha1);
> + data = unpack_entry_data(obj, sha1);
> obj->idx.crc32 = input_crc32;
> return data;
> }
> @@ -1186,6 +1280,8 @@ static void parse_pack_objects(unsigned char *sha1)
> nr_deltas++;
> delta->obj_no = i;
> delta++;
> + } else if (!data && obj->type == OBJ_PV4_TREE) {
> + /* delay sha1_object() until second pass */
> } else if (!data) {
> /* large blobs, check later */
> obj->real_type = OBJ_BAD;
> --
> 1.8.2.83.gc99314b
>
> --
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