diff options
Diffstat (limited to 'sha1_file.c')
| -rw-r--r-- | sha1_file.c | 55 |
1 files changed, 48 insertions, 7 deletions
diff --git a/sha1_file.c b/sha1_file.c index 89d7e5eb57..e002056b85 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -380,7 +380,7 @@ void add_to_alternates_file(const char *reference) { struct lock_file *lock = xcalloc(1, sizeof(struct lock_file)); int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), LOCK_DIE_ON_ERROR); - char *alt = mkpath("%s/objects\n", reference); + char *alt = mkpath("%s\n", reference); write_or_die(fd, alt, strlen(alt)); if (commit_lock_file(lock)) die("could not close alternates file"); @@ -1217,14 +1217,34 @@ static int experimental_loose_object(unsigned char *map) unsigned int word; /* - * Is it a zlib-compressed buffer? If so, the first byte - * must be 0x78 (15-bit window size, deflated), and the - * first 16-bit word is evenly divisible by 31. If so, - * we are looking at the official format, not the experimental - * one. + * We must determine if the buffer contains the standard + * zlib-deflated stream or the experimental format based + * on the in-pack object format. Compare the header byte + * for each format: + * + * RFC1950 zlib w/ deflate : 0www1000 : 0 <= www <= 7 + * Experimental pack-based : Stttssss : ttt = 1,2,3,4 + * + * If bit 7 is clear and bits 0-3 equal 8, the buffer MUST be + * in standard loose-object format, UNLESS it is a Git-pack + * format object *exactly* 8 bytes in size when inflated. + * + * However, RFC1950 also specifies that the 1st 16-bit word + * must be divisible by 31 - this checksum tells us our buffer + * is in the standard format, giving a false positive only if + * the 1st word of the Git-pack format object happens to be + * divisible by 31, ie: + * ((byte0 * 256) + byte1) % 31 = 0 + * => 0ttt10000www1000 % 31 = 0 + * + * As it happens, this case can only arise for www=3 & ttt=1 + * - ie, a Commit object, which would have to be 8 bytes in + * size. As no Commit can be that small, we find that the + * combination of these two criteria (bitmask & checksum) + * can always correctly determine the buffer format. */ word = (map[0] << 8) + map[1]; - if (map[0] == 0x78 && !(word % 31)) + if ((map[0] & 0x8F) == 0x08 && !(word % 31)) return 0; else return 1; @@ -1797,6 +1817,24 @@ static void *unpack_delta_entry(struct packed_git *p, return result; } +static void write_pack_access_log(struct packed_git *p, off_t obj_offset) +{ + static FILE *log_file; + + if (!log_file) { + log_file = fopen(log_pack_access, "w"); + if (!log_file) { + error("cannot open pack access log '%s' for writing: %s", + log_pack_access, strerror(errno)); + log_pack_access = NULL; + return; + } + } + fprintf(log_file, "%s %"PRIuMAX"\n", + p->pack_name, (uintmax_t)obj_offset); + fflush(log_file); +} + int do_check_packed_object_crc; void *unpack_entry(struct packed_git *p, off_t obj_offset, @@ -1806,6 +1844,9 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset, off_t curpos = obj_offset; void *data; + if (log_pack_access) + write_pack_access_log(p, obj_offset); + if (do_check_packed_object_crc && p->index_version > 1) { struct revindex_entry *revidx = find_pack_revindex(p, obj_offset); unsigned long len = revidx[1].offset - obj_offset; |