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 * Note that oe_set_size() becomes expensive when the given size is 12 * above this limit. Don't lower it too much. 13 */ 14#define OE_SIZE_BITS 31 15 16/* 17 * State flags for depth-first search used for analyzing delta cycles. 18 * 19 * The depth is measured in delta-links to the base (so if A is a delta 20 * against B, then A has a depth of 1, and B a depth of 0). 21 */ 22enum dfs_state { 23 DFS_NONE = 0, 24 DFS_ACTIVE, 25 DFS_DONE, 26 DFS_NUM_STATES 27}; 28 29/* 30 * basic object info 31 * ----------------- 32 * idx.oid is filled up before delta searching starts. idx.crc32 is 33 * only valid after the object is written out and will be used for 34 * generating the index. idx.offset will be both gradually set and 35 * used in writing phase (base objects get offset first, then deltas 36 * refer to them) 37 * 38 * "size" is the uncompressed object size. Compressed size of the raw 39 * data for an object in a pack is not stored anywhere but is computed 40 * and made available when reverse .idx is made. Note that when a 41 * delta is reused, "size" is the uncompressed _delta_ size, not the 42 * canonical one after the delta has been applied. 43 * 44 * "hash" contains a path name hash which is used for sorting the 45 * delta list and also during delta searching. Once prepare_pack() 46 * returns it's no longer needed. 47 * 48 * source pack info 49 * ---------------- 50 * The (in_pack, in_pack_offset) tuple contains the location of the 51 * object in the source pack. in_pack_header_size allows quickly 52 * skipping the header and going straight to the zlib stream. 53 * 54 * "type" and "in_pack_type" both describe object type. in_pack_type 55 * may contain a delta type, while type is always the canonical type. 56 * 57 * deltas 58 * ------ 59 * Delta links (delta, delta_child and delta_sibling) are created to 60 * reflect that delta graph from the source pack then updated or added 61 * during delta searching phase when we find better deltas. 62 * 63 * delta_child and delta_sibling are last needed in 64 * compute_write_order(). "delta" and "delta_size" must remain valid 65 * at object writing phase in case the delta is not cached. 66 * 67 * If a delta is cached in memory and is compressed, delta_data points 68 * to the data and z_delta_size contains the compressed size. If it's 69 * uncompressed [1], z_delta_size must be zero. delta_size is always 70 * the uncompressed size and must be valid even if the delta is not 71 * cached. 72 * 73 * [1] during try_delta phase we don't bother with compressing because 74 * the delta could be quickly replaced with a better one. 75 */ 76struct object_entry { 77 struct pack_idx_entry idx; 78 unsigned size_:OE_SIZE_BITS; 79 unsigned size_valid:1; 80 unsigned in_pack_idx:OE_IN_PACK_BITS; /* already in pack */ 81 off_t in_pack_offset; 82 uint32_t delta_idx; /* delta base object */ 83 uint32_t delta_child_idx; /* deltified objects who bases me */ 84 uint32_t delta_sibling_idx; /* other deltified objects who 85 * uses the same base as me 86 */ 87 void *delta_data; /* cached delta (uncompressed) */ 88 unsigned long delta_size; /* delta data size (uncompressed) */ 89 unsigned z_delta_size:OE_Z_DELTA_BITS; 90 unsigned type_:TYPE_BITS; 91 unsigned in_pack_type:TYPE_BITS; /* could be delta */ 92 unsigned type_valid:1; 93 uint32_t hash; /* name hint hash */ 94 unsigned char in_pack_header_size; 95 unsigned preferred_base:1; /* 96 * we do not pack this, but is available 97 * to be used as the base object to delta 98 * objects against. 99 */ 100 unsigned no_try_delta:1; 101 unsigned tagged:1; /* near the very tip of refs */ 102 unsigned filled:1; /* assigned write-order */ 103 unsigned dfs_state:OE_DFS_STATE_BITS; 104 unsigned depth:OE_DEPTH_BITS; 105}; 106 107struct packing_data { 108 struct object_entry *objects; 109 uint32_t nr_objects, nr_alloc; 110 111 int32_t *index; 112 uint32_t index_size; 113 114 unsigned int *in_pack_pos; 115 116 /* 117 * Only one of these can be non-NULL and they have different 118 * sizes. if in_pack_by_idx is allocated, oe_in_pack() returns 119 * the pack of an object using in_pack_idx field. If not, 120 * in_pack[] array is used the same way as in_pack_pos[] 121 */ 122 struct packed_git **in_pack_by_idx; 123 struct packed_git **in_pack; 124 125 uintmax_t oe_size_limit; 126}; 127 128void prepare_packing_data(struct packing_data *pdata); 129struct object_entry *packlist_alloc(struct packing_data *pdata, 130 const unsigned char *sha1, 131 uint32_t index_pos); 132 133struct object_entry *packlist_find(struct packing_data *pdata, 134 const unsigned char *sha1, 135 uint32_t *index_pos); 136 137static inline uint32_t pack_name_hash(const char *name) 138{ 139 uint32_t c, hash = 0; 140 141 if (!name) 142 return 0; 143 144 /* 145 * This effectively just creates a sortable number from the 146 * last sixteen non-whitespace characters. Last characters 147 * count "most", so things that end in ".c" sort together. 148 */ 149 while ((c = *name++) != 0) { 150 if (isspace(c)) 151 continue; 152 hash = (hash >> 2) + (c << 24); 153 } 154 return hash; 155} 156 157static inline enum object_type oe_type(const struct object_entry *e) 158{ 159 return e->type_valid ? e->type_ : OBJ_BAD; 160} 161 162static inline void oe_set_type(struct object_entry *e, 163 enum object_type type) 164{ 165 if (type >= OBJ_ANY) 166 BUG("OBJ_ANY cannot be set in pack-objects code"); 167 168 e->type_valid = type >= OBJ_NONE; 169 e->type_ = (unsigned)type; 170} 171 172static inline unsigned int oe_in_pack_pos(const struct packing_data *pack, 173 const struct object_entry *e) 174{ 175 return pack->in_pack_pos[e - pack->objects]; 176} 177 178static inline void oe_set_in_pack_pos(const struct packing_data *pack, 179 const struct object_entry *e, 180 unsigned int pos) 181{ 182 pack->in_pack_pos[e - pack->objects] = pos; 183} 184 185static inline struct packed_git *oe_in_pack(const struct packing_data *pack, 186 const struct object_entry *e) 187{ 188 if (pack->in_pack_by_idx) 189 return pack->in_pack_by_idx[e->in_pack_idx]; 190 else 191 return pack->in_pack[e - pack->objects]; 192} 193 194void oe_map_new_pack(struct packing_data *pack, 195 struct packed_git *p); 196static inline void oe_set_in_pack(struct packing_data *pack, 197 struct object_entry *e, 198 struct packed_git *p) 199{ 200 if (!p->index) 201 oe_map_new_pack(pack, p); 202 if (pack->in_pack_by_idx) 203 e->in_pack_idx = p->index; 204 else 205 pack->in_pack[e - pack->objects] = p; 206} 207 208static inline struct object_entry *oe_delta( 209 const struct packing_data *pack, 210 const struct object_entry *e) 211{ 212 if (e->delta_idx) 213 return &pack->objects[e->delta_idx - 1]; 214 return NULL; 215} 216 217static inline void oe_set_delta(struct packing_data *pack, 218 struct object_entry *e, 219 struct object_entry *delta) 220{ 221 if (delta) 222 e->delta_idx = (delta - pack->objects) + 1; 223 else 224 e->delta_idx = 0; 225} 226 227static inline struct object_entry *oe_delta_child( 228 const struct packing_data *pack, 229 const struct object_entry *e) 230{ 231 if (e->delta_child_idx) 232 return &pack->objects[e->delta_child_idx - 1]; 233 return NULL; 234} 235 236static inline void oe_set_delta_child(struct packing_data *pack, 237 struct object_entry *e, 238 struct object_entry *delta) 239{ 240 if (delta) 241 e->delta_child_idx = (delta - pack->objects) + 1; 242 else 243 e->delta_child_idx = 0; 244} 245 246static inline struct object_entry *oe_delta_sibling( 247 const struct packing_data *pack, 248 const struct object_entry *e) 249{ 250 if (e->delta_sibling_idx) 251 return &pack->objects[e->delta_sibling_idx - 1]; 252 return NULL; 253} 254 255static inline void oe_set_delta_sibling(struct packing_data *pack, 256 struct object_entry *e, 257 struct object_entry *delta) 258{ 259 if (delta) 260 e->delta_sibling_idx = (delta - pack->objects) + 1; 261 else 262 e->delta_sibling_idx = 0; 263} 264 265unsigned long oe_get_size_slow(struct packing_data *pack, 266 const struct object_entry *e); 267static inline unsigned long oe_size(struct packing_data *pack, 268 const struct object_entry *e) 269{ 270 if (e->size_valid) 271 return e->size_; 272 273 return oe_get_size_slow(pack, e); 274} 275 276static inline int oe_size_less_than(struct packing_data *pack, 277 const struct object_entry *lhs, 278 unsigned long rhs) 279{ 280 if (lhs->size_valid) 281 return lhs->size_ < rhs; 282 if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */ 283 return 0; 284 return oe_get_size_slow(pack, lhs) < rhs; 285} 286 287static inline int oe_size_greater_than(struct packing_data *pack, 288 const struct object_entry *lhs, 289 unsigned long rhs) 290{ 291 if (lhs->size_valid) 292 return lhs->size_ > rhs; 293 if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */ 294 return 1; 295 return oe_get_size_slow(pack, lhs) > rhs; 296} 297 298static inline void oe_set_size(struct packing_data *pack, 299 struct object_entry *e, 300 unsigned long size) 301{ 302 if (size < pack->oe_size_limit) { 303 e->size_ = size; 304 e->size_valid = 1; 305 } else { 306 e->size_valid = 0; 307 if (oe_get_size_slow(pack, e) != size) 308 BUG("'size' is supposed to be the object size!"); 309 } 310} 311 312#endif