1#ifndef PACK_OBJECTS_H 2#define PACK_OBJECTS_H 3 4#define OE_DFS_STATE_BITS 2 5#define OE_DEPTH_BITS 12 6 7/* 8 * State flags for depth-first search used for analyzing delta cycles. 9 * 10 * The depth is measured in delta-links to the base (so if A is a delta 11 * against B, then A has a depth of 1, and B a depth of 0). 12 */ 13enum dfs_state { 14 DFS_NONE = 0, 15 DFS_ACTIVE, 16 DFS_DONE, 17 DFS_NUM_STATES 18}; 19 20/* 21 * basic object info 22 * ----------------- 23 * idx.oid is filled up before delta searching starts. idx.crc32 is 24 * only valid after the object is written out and will be used for 25 * generating the index. idx.offset will be both gradually set and 26 * used in writing phase (base objects get offset first, then deltas 27 * refer to them) 28 * 29 * "size" is the uncompressed object size. Compressed size of the raw 30 * data for an object in a pack is not stored anywhere but is computed 31 * and made available when reverse .idx is made. 32 * 33 * "hash" contains a path name hash which is used for sorting the 34 * delta list and also during delta searching. Once prepare_pack() 35 * returns it's no longer needed. 36 * 37 * source pack info 38 * ---------------- 39 * The (in_pack, in_pack_offset) tuple contains the location of the 40 * object in the source pack. in_pack_header_size allows quickly 41 * skipping the header and going straight to the zlib stream. 42 * 43 * "type" and "in_pack_type" both describe object type. in_pack_type 44 * may contain a delta type, while type is always the canonical type. 45 * 46 * deltas 47 * ------ 48 * Delta links (delta, delta_child and delta_sibling) are created to 49 * reflect that delta graph from the source pack then updated or added 50 * during delta searching phase when we find better deltas. 51 * 52 * delta_child and delta_sibling are last needed in 53 * compute_write_order(). "delta" and "delta_size" must remain valid 54 * at object writing phase in case the delta is not cached. 55 * 56 * If a delta is cached in memory and is compressed, delta_data points 57 * to the data and z_delta_size contains the compressed size. If it's 58 * uncompressed [1], z_delta_size must be zero. delta_size is always 59 * the uncompressed size and must be valid even if the delta is not 60 * cached. 61 * 62 * [1] during try_delta phase we don't bother with compressing because 63 * the delta could be quickly replaced with a better one. 64 */ 65struct object_entry { 66 struct pack_idx_entry idx; 67 unsigned long size; /* uncompressed size */ 68 struct packed_git *in_pack; /* already in pack */ 69 off_t in_pack_offset; 70 struct object_entry *delta; /* delta base object */ 71 struct object_entry *delta_child; /* deltified objects who bases me */ 72 struct object_entry *delta_sibling; /* other deltified objects who 73 * uses the same base as me 74 */ 75 void *delta_data; /* cached delta (uncompressed) */ 76 unsigned long delta_size; /* delta data size (uncompressed) */ 77 unsigned long z_delta_size; /* delta data size (compressed) */ 78 unsigned type_:TYPE_BITS; 79 unsigned in_pack_type:TYPE_BITS; /* could be delta */ 80 unsigned type_valid:1; 81 uint32_t hash; /* name hint hash */ 82 unsigned char in_pack_header_size; 83 unsigned preferred_base:1; /* 84 * we do not pack this, but is available 85 * to be used as the base object to delta 86 * objects against. 87 */ 88 unsigned no_try_delta:1; 89 unsigned tagged:1; /* near the very tip of refs */ 90 unsigned filled:1; /* assigned write-order */ 91 unsigned dfs_state:OE_DFS_STATE_BITS; 92 unsigned depth:OE_DEPTH_BITS; 93}; 94 95struct packing_data { 96 struct object_entry *objects; 97 uint32_t nr_objects, nr_alloc; 98 99 int32_t *index; 100 uint32_t index_size; 101 102 unsigned int *in_pack_pos; 103}; 104 105struct object_entry *packlist_alloc(struct packing_data *pdata, 106 const unsigned char *sha1, 107 uint32_t index_pos); 108 109struct object_entry *packlist_find(struct packing_data *pdata, 110 const unsigned char *sha1, 111 uint32_t *index_pos); 112 113static inline uint32_t pack_name_hash(const char *name) 114{ 115 uint32_t c, hash = 0; 116 117 if (!name) 118 return 0; 119 120 /* 121 * This effectively just creates a sortable number from the 122 * last sixteen non-whitespace characters. Last characters 123 * count "most", so things that end in ".c" sort together. 124 */ 125 while ((c = *name++) != 0) { 126 if (isspace(c)) 127 continue; 128 hash = (hash >> 2) + (c << 24); 129 } 130 return hash; 131} 132 133static inline enum object_type oe_type(const struct object_entry *e) 134{ 135 return e->type_valid ? e->type_ : OBJ_BAD; 136} 137 138static inline void oe_set_type(struct object_entry *e, 139 enum object_type type) 140{ 141 if (type >= OBJ_ANY) 142 BUG("OBJ_ANY cannot be set in pack-objects code"); 143 144 e->type_valid = type >= OBJ_NONE; 145 e->type_ = (unsigned)type; 146} 147 148static inline unsigned int oe_in_pack_pos(const struct packing_data *pack, 149 const struct object_entry *e) 150{ 151 return pack->in_pack_pos[e - pack->objects]; 152} 153 154static inline void oe_set_in_pack_pos(const struct packing_data *pack, 155 const struct object_entry *e, 156 unsigned int pos) 157{ 158 pack->in_pack_pos[e - pack->objects] = pos; 159} 160 161#endif