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 int in_pack_pos; 83 unsigned char in_pack_header_size; 84 unsigned preferred_base:1; /* 85 * we do not pack this, but is available 86 * to be used as the base object to delta 87 * objects against. 88 */ 89 unsigned no_try_delta:1; 90 unsigned tagged:1; /* near the very tip of refs */ 91 unsigned filled:1; /* assigned write-order */ 92 unsigned dfs_state:OE_DFS_STATE_BITS; 93 unsigned depth:OE_DEPTH_BITS; 94}; 95 96struct packing_data { 97 struct object_entry *objects; 98 uint32_t nr_objects, nr_alloc; 99 100 int32_t *index; 101 uint32_t index_size; 102}; 103 104struct object_entry *packlist_alloc(struct packing_data *pdata, 105 const unsigned char *sha1, 106 uint32_t index_pos); 107 108struct object_entry *packlist_find(struct packing_data *pdata, 109 const unsigned char *sha1, 110 uint32_t *index_pos); 111 112static inline uint32_t pack_name_hash(const char *name) 113{ 114 uint32_t c, hash = 0; 115 116 if (!name) 117 return 0; 118 119 /* 120 * This effectively just creates a sortable number from the 121 * last sixteen non-whitespace characters. Last characters 122 * count "most", so things that end in ".c" sort together. 123 */ 124 while ((c = *name++) != 0) { 125 if (isspace(c)) 126 continue; 127 hash = (hash >> 2) + (c << 24); 128 } 129 return hash; 130} 131 132static inline enum object_type oe_type(const struct object_entry *e) 133{ 134 return e->type_valid ? e->type_ : OBJ_BAD; 135} 136 137static inline void oe_set_type(struct object_entry *e, 138 enum object_type type) 139{ 140 if (type >= OBJ_ANY) 141 BUG("OBJ_ANY cannot be set in pack-objects code"); 142 143 e->type_valid = type >= OBJ_NONE; 144 e->type_ = (unsigned)type; 145} 146 147#endif