diff options
Diffstat (limited to 'pack.h')
| -rw-r--r-- | pack.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/pack.h b/pack.h new file mode 100644 index 0000000000..d4d412ccbb --- /dev/null +++ b/pack.h @@ -0,0 +1,52 @@ +#ifndef PACK_H +#define PACK_H + +#include "object.h" + +/* + * Packed object header + */ +#define PACK_SIGNATURE 0x5041434b /* "PACK" */ +#define PACK_VERSION 2 +#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3)) +struct pack_header { + uint32_t hdr_signature; + uint32_t hdr_version; + uint32_t hdr_entries; +}; + +/* + * The first four bytes of index formats later than version 1 should + * start with this signature, as all older git binaries would find this + * value illegal and abort reading the file. + * + * This is the case because the number of objects in a packfile + * cannot exceed 1,431,660,000 as every object would need at least + * 3 bytes of data and the overall packfile cannot exceed 4 GiB with + * version 1 of the index file due to the offsets limited to 32 bits. + * Clearly the signature exceeds this maximum. + * + * Very old git binaries will also compare the first 4 bytes to the + * next 4 bytes in the index and abort with a "non-monotonic index" + * error if the second 4 byte word is smaller than the first 4 + * byte word. This would be true in the proposed future index + * format as idx_signature would be greater than idx_version. + */ +#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */ + +/* + * Packed object index header + */ +struct pack_idx_header { + uint32_t idx_signature; + uint32_t idx_version; +}; + + +extern int verify_pack(struct packed_git *, int); + +#define PH_ERROR_EOF (-1) +#define PH_ERROR_PACK_SIGNATURE (-2) +#define PH_ERROR_PROTOCOL (-3) +extern int read_pack_header(int fd, struct pack_header *); +#endif |