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 enum object_type type; 63 enum object_type in_pack_type; /* could be delta */ 64 uint32_t hash; /* name hint hash */ 65 unsigned int in_pack_pos; 66 unsigned char in_pack_header_size; 67 unsigned preferred_base:1; /* 68 * we do not pack this, but is available 69 * to be used as the base object to delta 70 * objects against. 71 */ 72 unsigned no_try_delta:1; 73 unsigned tagged:1; /* near the very tip of refs */ 74 unsigned filled:1; /* assigned write-order */ 75 76 /* 77 * State flags for depth-first search used for analyzing delta cycles. 78 * 79 * The depth is measured in delta-links to the base (so if A is a delta 80 * against B, then A has a depth of 1, and B a depth of 0). 81 */ 82 enum { 83 DFS_NONE = 0, 84 DFS_ACTIVE, 85 DFS_DONE 86 } dfs_state; 87 int depth; 88}; 89 90struct packing_data { 91 struct object_entry *objects; 92 uint32_t nr_objects, nr_alloc; 93 94 int32_t *index; 95 uint32_t index_size; 96}; 97 98struct object_entry *packlist_alloc(struct packing_data *pdata, 99 const unsigned char *sha1, 100 uint32_t index_pos); 101 102struct object_entry *packlist_find(struct packing_data *pdata, 103 const unsigned char *sha1, 104 uint32_t *index_pos); 105 106static inline uint32_t pack_name_hash(const char *name) 107{ 108 uint32_t c, hash = 0; 109 110 if (!name) 111 return 0; 112 113 /* 114 * This effectively just creates a sortable number from the 115 * last sixteen non-whitespace characters. Last characters 116 * count "most", so things that end in ".c" sort together. 117 */ 118 while ((c = *name++) != 0) { 119 if (isspace(c)) 120 continue; 121 hash = (hash >> 2) + (c << 24); 122 } 123 return hash; 124} 125 126#endif