1#ifndef PACK_OBJECTS_H 2#define PACK_OBJECTS_H 3 4#include "object-store.h" 5 6#define OE_DFS_STATE_BITS 2 7#define OE_DEPTH_BITS 12 8#define OE_IN_PACK_BITS 10 9#define OE_Z_DELTA_BITS 20 10 11/* 12 * State flags for depth-first search used for analyzing delta cycles. 13 * 14 * The depth is measured in delta-links to the base (so if A is a delta 15 * against B, then A has a depth of 1, and B a depth of 0). 16 */ 17enum dfs_state { 18 DFS_NONE = 0, 19 DFS_ACTIVE, 20 DFS_DONE, 21 DFS_NUM_STATES 22}; 23 24/* 25 * basic object info 26 * ----------------- 27 * idx.oid is filled up before delta searching starts. idx.crc32 is 28 * only valid after the object is written out and will be used for 29 * generating the index. idx.offset will be both gradually set and 30 * used in writing phase (base objects get offset first, then deltas 31 * refer to them) 32 * 33 * "size" is the uncompressed object size. Compressed size of the raw 34 * data for an object in a pack is not stored anywhere but is computed 35 * and made available when reverse .idx is made. Note that when a 36 * delta is reused, "size" is the uncompressed _delta_ size, not the 37 * canonical one after the delta has been applied. 38 * 39 * "hash" contains a path name hash which is used for sorting the 40 * delta list and also during delta searching. Once prepare_pack() 41 * returns it's no longer needed. 42 * 43 * source pack info 44 * ---------------- 45 * The (in_pack, in_pack_offset) tuple contains the location of the 46 * object in the source pack. in_pack_header_size allows quickly 47 * skipping the header and going straight to the zlib stream. 48 * 49 * "type" and "in_pack_type" both describe object type. in_pack_type 50 * may contain a delta type, while type is always the canonical type. 51 * 52 * deltas 53 * ------ 54 * Delta links (delta, delta_child and delta_sibling) are created to 55 * reflect that delta graph from the source pack then updated or added 56 * during delta searching phase when we find better deltas. 57 * 58 * delta_child and delta_sibling are last needed in 59 * compute_write_order(). "delta" and "delta_size" must remain valid 60 * at object writing phase in case the delta is not cached. 61 * 62 * If a delta is cached in memory and is compressed, delta_data points 63 * to the data and z_delta_size contains the compressed size. If it's 64 * uncompressed [1], z_delta_size must be zero. delta_size is always 65 * the uncompressed size and must be valid even if the delta is not 66 * cached. 67 * 68 * [1] during try_delta phase we don't bother with compressing because 69 * the delta could be quickly replaced with a better one. 70 */ 71struct object_entry { 72 struct pack_idx_entry idx; 73 unsigned long size; /* uncompressed size */ 74 unsigned in_pack_idx:OE_IN_PACK_BITS; /* already in pack */ 75 off_t in_pack_offset; 76 uint32_t delta_idx; /* delta base object */ 77 uint32_t delta_child_idx; /* deltified objects who bases me */ 78 uint32_t delta_sibling_idx; /* other deltified objects who 79 * uses the same base as me 80 */ 81 void *delta_data; /* cached delta (uncompressed) */ 82 unsigned long delta_size; /* delta data size (uncompressed) */ 83 unsigned z_delta_size:OE_Z_DELTA_BITS; 84 unsigned type_:TYPE_BITS; 85 unsigned in_pack_type:TYPE_BITS; /* could be delta */ 86 unsigned type_valid:1; 87 uint32_t hash; /* name hint hash */ 88 unsigned char in_pack_header_size; 89 unsigned preferred_base:1; /* 90 * we do not pack this, but is available 91 * to be used as the base object to delta 92 * objects against. 93 */ 94 unsigned no_try_delta:1; 95 unsigned tagged:1; /* near the very tip of refs */ 96 unsigned filled:1; /* assigned write-order */ 97 unsigned dfs_state:OE_DFS_STATE_BITS; 98 unsigned depth:OE_DEPTH_BITS; 99}; 100 101struct packing_data { 102 struct object_entry *objects; 103 uint32_t nr_objects, nr_alloc; 104 105 int32_t *index; 106 uint32_t index_size; 107 108 unsigned int *in_pack_pos; 109 110 /* 111 * Only one of these can be non-NULL and they have different 112 * sizes. if in_pack_by_idx is allocated, oe_in_pack() returns 113 * the pack of an object using in_pack_idx field. If not, 114 * in_pack[] array is used the same way as in_pack_pos[] 115 */ 116 struct packed_git **in_pack_by_idx; 117 struct packed_git **in_pack; 118}; 119 120void prepare_packing_data(struct packing_data *pdata); 121struct object_entry *packlist_alloc(struct packing_data *pdata, 122 const unsigned char *sha1, 123 uint32_t index_pos); 124 125struct object_entry *packlist_find(struct packing_data *pdata, 126 const unsigned char *sha1, 127 uint32_t *index_pos); 128 129static inline uint32_t pack_name_hash(const char *name) 130{ 131 uint32_t c, hash = 0; 132 133 if (!name) 134 return 0; 135 136 /* 137 * This effectively just creates a sortable number from the 138 * last sixteen non-whitespace characters. Last characters 139 * count "most", so things that end in ".c" sort together. 140 */ 141 while ((c = *name++) != 0) { 142 if (isspace(c)) 143 continue; 144 hash = (hash >> 2) + (c << 24); 145 } 146 return hash; 147} 148 149static inline enum object_type oe_type(const struct object_entry *e) 150{ 151 return e->type_valid ? e->type_ : OBJ_BAD; 152} 153 154static inline void oe_set_type(struct object_entry *e, 155 enum object_type type) 156{ 157 if (type >= OBJ_ANY) 158 BUG("OBJ_ANY cannot be set in pack-objects code"); 159 160 e->type_valid = type >= OBJ_NONE; 161 e->type_ = (unsigned)type; 162} 163 164static inline unsigned int oe_in_pack_pos(const struct packing_data *pack, 165 const struct object_entry *e) 166{ 167 return pack->in_pack_pos[e - pack->objects]; 168} 169 170static inline void oe_set_in_pack_pos(const struct packing_data *pack, 171 const struct object_entry *e, 172 unsigned int pos) 173{ 174 pack->in_pack_pos[e - pack->objects] = pos; 175} 176 177static inline struct packed_git *oe_in_pack(const struct packing_data *pack, 178 const struct object_entry *e) 179{ 180 if (pack->in_pack_by_idx) 181 return pack->in_pack_by_idx[e->in_pack_idx]; 182 else 183 return pack->in_pack[e - pack->objects]; 184} 185 186void oe_map_new_pack(struct packing_data *pack, 187 struct packed_git *p); 188static inline void oe_set_in_pack(struct packing_data *pack, 189 struct object_entry *e, 190 struct packed_git *p) 191{ 192 if (!p->index) 193 oe_map_new_pack(pack, p); 194 if (pack->in_pack_by_idx) 195 e->in_pack_idx = p->index; 196 else 197 pack->in_pack[e - pack->objects] = p; 198} 199 200static inline struct object_entry *oe_delta( 201 const struct packing_data *pack, 202 const struct object_entry *e) 203{ 204 if (e->delta_idx) 205 return &pack->objects[e->delta_idx - 1]; 206 return NULL; 207} 208 209static inline void oe_set_delta(struct packing_data *pack, 210 struct object_entry *e, 211 struct object_entry *delta) 212{ 213 if (delta) 214 e->delta_idx = (delta - pack->objects) + 1; 215 else 216 e->delta_idx = 0; 217} 218 219static inline struct object_entry *oe_delta_child( 220 const struct packing_data *pack, 221 const struct object_entry *e) 222{ 223 if (e->delta_child_idx) 224 return &pack->objects[e->delta_child_idx - 1]; 225 return NULL; 226} 227 228static inline void oe_set_delta_child(struct packing_data *pack, 229 struct object_entry *e, 230 struct object_entry *delta) 231{ 232 if (delta) 233 e->delta_child_idx = (delta - pack->objects) + 1; 234 else 235 e->delta_child_idx = 0; 236} 237 238static inline struct object_entry *oe_delta_sibling( 239 const struct packing_data *pack, 240 const struct object_entry *e) 241{ 242 if (e->delta_sibling_idx) 243 return &pack->objects[e->delta_sibling_idx - 1]; 244 return NULL; 245} 246 247static inline void oe_set_delta_sibling(struct packing_data *pack, 248 struct object_entry *e, 249 struct object_entry *delta) 250{ 251 if (delta) 252 e->delta_sibling_idx = (delta - pack->objects) + 1; 253 else 254 e->delta_sibling_idx = 0; 255} 256 257#endif