1#ifndef PACK_OBJECTS_H 2#define PACK_OBJECTS_H 3 4/* 5 * basic object info 6 * ----------------- 7 * idx.oid is filled up before delta searching starts. idx.crc32 is 8 * only valid after the object is written out and will be used for 9 * generating the index. idx.offset will be both gradually set and 10 * used in writing phase (base objects get offset first, then deltas 11 * refer to them) 12 * 13 * "size" is the uncompressed object size. Compressed size of the raw 14 * data for an object in a pack is not stored anywhere but is computed 15 * and made available when reverse .idx is made. 16 * 17 * "hash" contains a path name hash which is used for sorting the 18 * delta list and also during delta searching. Once prepare_pack() 19 * returns it's no longer needed. 20 * 21 * source pack info 22 * ---------------- 23 * The (in_pack, in_pack_offset) tuple contains the location of the 24 * object in the source pack. in_pack_header_size allows quickly 25 * skipping the header and going straight to the zlib stream. 26 * 27 * "type" and "in_pack_type" both describe object type. in_pack_type 28 * may contain a delta type, while type is always the canonical type. 29 * 30 * deltas 31 * ------ 32 * Delta links (delta, delta_child and delta_sibling) are created to 33 * reflect that delta graph from the source pack then updated or added 34 * during delta searching phase when we find better deltas. 35 * 36 * delta_child and delta_sibling are last needed in 37 * compute_write_order(). "delta" and "delta_size" must remain valid 38 * at object writing phase in case the delta is not cached. 39 * 40 * If a delta is cached in memory and is compressed, delta_data points 41 * to the data and z_delta_size contains the compressed size. If it's 42 * uncompressed [1], z_delta_size must be zero. delta_size is always 43 * the uncompressed size and must be valid even if the delta is not 44 * cached. 45 * 46 * [1] during try_delta phase we don't bother with compressing because 47 * the delta could be quickly replaced with a better one. 48 */ 49struct object_entry { 50 struct pack_idx_entry idx; 51 unsigned long size; /* uncompressed size */ 52 struct packed_git *in_pack; /* already in pack */ 53 off_t in_pack_offset; 54 struct object_entry *delta; /* delta base object */ 55 struct object_entry *delta_child; /* deltified objects who bases me */ 56 struct object_entry *delta_sibling; /* other deltified objects who 57 * uses the same base as me 58 */ 59 void *delta_data; /* cached delta (uncompressed) */ 60 unsigned long delta_size; /* delta data size (uncompressed) */ 61 unsigned long z_delta_size; /* delta data size (compressed) */ 62 unsigned type_:TYPE_BITS; 63 unsigned in_pack_type:TYPE_BITS; /* could be delta */ 64 unsigned type_valid:1; 65 uint32_t hash; /* name hint hash */ 66 unsigned int in_pack_pos; 67 unsigned char in_pack_header_size; 68 unsigned preferred_base:1; /* 69 * we do not pack this, but is available 70 * to be used as the base object to delta 71 * objects against. 72 */ 73 unsigned no_try_delta:1; 74 unsigned tagged:1; /* near the very tip of refs */ 75 unsigned filled:1; /* assigned write-order */ 76 77 /* 78 * State flags for depth-first search used for analyzing delta cycles. 79 * 80 * The depth is measured in delta-links to the base (so if A is a delta 81 * against B, then A has a depth of 1, and B a depth of 0). 82 */ 83 enum { 84 DFS_NONE = 0, 85 DFS_ACTIVE, 86 DFS_DONE 87 } dfs_state; 88 int depth; 89}; 90 91struct packing_data { 92 struct object_entry *objects; 93 uint32_t nr_objects, nr_alloc; 94 95 int32_t *index; 96 uint32_t index_size; 97}; 98 99struct object_entry *packlist_alloc(struct packing_data *pdata, 100 const unsigned char *sha1, 101 uint32_t index_pos); 102 103struct object_entry *packlist_find(struct packing_data *pdata, 104 const unsigned char *sha1, 105 uint32_t *index_pos); 106 107static inline uint32_t pack_name_hash(const char *name) 108{ 109 uint32_t c, hash = 0; 110 111 if (!name) 112 return 0; 113 114 /* 115 * This effectively just creates a sortable number from the 116 * last sixteen non-whitespace characters. Last characters 117 * count "most", so things that end in ".c" sort together. 118 */ 119 while ((c = *name++) != 0) { 120 if (isspace(c)) 121 continue; 122 hash = (hash >> 2) + (c << 24); 123 } 124 return hash; 125} 126 127static inline enum object_type oe_type(const struct object_entry *e) 128{ 129 return e->type_valid ? e->type_ : OBJ_BAD; 130} 131 132static inline void oe_set_type(struct object_entry *e, 133 enum object_type type) 134{ 135 if (type >= OBJ_ANY) 136 BUG("OBJ_ANY cannot be set in pack-objects code"); 137 138 e->type_valid = type >= OBJ_NONE; 139 e->type_ = (unsigned)type; 140} 141 142#endif