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| | #ifndef PACK_OBJECTS_H
#define PACK_OBJECTS_H
#define OE_DFS_STATE_BITS 2
#define OE_DEPTH_BITS 12
/*
* State flags for depth-first search used for analyzing delta cycles.
*
* The depth is measured in delta-links to the base (so if A is a delta
* against B, then A has a depth of 1, and B a depth of 0).
*/
enum dfs_state {
DFS_NONE = 0,
DFS_ACTIVE,
DFS_DONE,
DFS_NUM_STATES
};
/*
* basic object info
* -----------------
* idx.oid is filled up before delta searching starts. idx.crc32 and
* is only valid after the object is written down and will be used for
* generating the index. idx.offset will be both gradually set and
* used in writing phase (base objects get offset first, then deltas
* refer to them)
*
* "size" is the uncompressed object size. Compressed size is not
* cached (ie. raw data in a pack) but available via revindex.
*
* "hash" contains a path name hash which is used for sorting the
* delta list and also during delta searching. Once prepare_pack()
* returns it's no longer needed.
*
* source pack info
* ----------------
* The (in_pack, in_pack_offset, in_pack_header_size) tuple contains
* the location of the object in the source pack, with or without
* header.
*
* "type" and "in_pack_type" both describe object type. in_pack_type
* may contain a delta type, while type is always the canonical type.
*
* deltas
* ------
* Delta links (delta, delta_child and delta_sibling) are created
* reflect that delta graph from the source pack then updated or added
* during delta searching phase when we find better deltas.
*
* delta_child and delta_sibling are last needed in
* compute_write_order(). "delta" and "delta_size" must remain valid
* at object writing phase in case the delta is not cached.
*
* If a delta is cached in memory and is compressed, "delta" points to
* the data and z_delta_size contains the compressed size. If it's
* uncompressed [1], z_delta_size must be zero. delta_size is always
* the uncompressed size and must be valid even if the delta is not
* cached. Delta recreation technically only depends on "delta"
* pointer, but delta_size is still used to verify it's the same as
* before.
*
* [1] during try_delta phase we don't bother with compressing because
* the delta could be quickly replaced with a better one.
*/
struct object_entry {
struct pack_idx_entry idx;
unsigned long size; /* uncompressed size */
struct packed_git *in_pack; /* already in pack */
off_t in_pack_offset;
struct object_entry *delta; /* delta base object */
struct object_entry *delta_child; /* deltified objects who bases me */
struct object_entry *delta_sibling; /* other deltified objects who
* uses the same base as me
*/
void *delta_data; /* cached delta (uncompressed) */
unsigned long delta_size; /* delta data size (uncompressed) */
unsigned long z_delta_size; /* delta data size (compressed) */
uint32_t hash; /* name hint hash */
unsigned int in_pack_pos;
unsigned char in_pack_header_size;
unsigned type:TYPE_BITS;
unsigned in_pack_type:TYPE_BITS; /* could be delta */
unsigned preferred_base:1; /*
* we do not pack this, but is available
* to be used as the base object to delta
* objects against.
*/
unsigned no_try_delta:1;
unsigned tagged:1; /* near the very tip of refs */
unsigned filled:1; /* assigned write-order */
unsigned dfs_state:OE_DFS_STATE_BITS;
unsigned depth:OE_DEPTH_BITS;
/* size: 120, bit_padding: 8 bits */
};
struct packing_data {
struct object_entry *objects;
uint32_t nr_objects, nr_alloc;
int32_t *index;
uint32_t index_size;
};
struct object_entry *packlist_alloc(struct packing_data *pdata,
const unsigned char *sha1,
uint32_t index_pos);
struct object_entry *packlist_find(struct packing_data *pdata,
const unsigned char *sha1,
uint32_t *index_pos);
static inline uint32_t pack_name_hash(const char *name)
{
uint32_t c, hash = 0;
if (!name)
return 0;
/*
* This effectively just creates a sortable number from the
* last sixteen non-whitespace characters. Last characters
* count "most", so things that end in ".c" sort together.
*/
while ((c = *name++) != 0) {
if (isspace(c))
continue;
hash = (hash >> 2) + (c << 24);
}
return hash;
}
#endif
|