1#ifndef PACK_OBJECTS_H 2#define PACK_OBJECTS_H 3 4#include"object-store.h" 5#include"thread-utils.h" 6#include"pack.h" 7 8#define DEFAULT_DELTA_CACHE_SIZE (256 * 1024 * 1024) 9 10#define OE_DFS_STATE_BITS 2 11#define OE_DEPTH_BITS 12 12#define OE_IN_PACK_BITS 10 13#define OE_Z_DELTA_BITS 20 14/* 15 * Note that oe_set_size() becomes expensive when the given size is 16 * above this limit. Don't lower it too much. 17 */ 18#define OE_SIZE_BITS 31 19#define OE_DELTA_SIZE_BITS 23 20 21/* 22 * State flags for depth-first search used for analyzing delta cycles. 23 * 24 * The depth is measured in delta-links to the base (so if A is a delta 25 * against B, then A has a depth of 1, and B a depth of 0). 26 */ 27enum dfs_state { 28 DFS_NONE =0, 29 DFS_ACTIVE, 30 DFS_DONE, 31 DFS_NUM_STATES 32}; 33 34/* 35 * The size of struct nearly determines pack-objects's memory 36 * consumption. This struct is packed tight for that reason. When you 37 * add or reorder something in this struct, think a bit about this. 38 * 39 * basic object info 40 * ----------------- 41 * idx.oid is filled up before delta searching starts. idx.crc32 is 42 * only valid after the object is written out and will be used for 43 * generating the index. idx.offset will be both gradually set and 44 * used in writing phase (base objects get offset first, then deltas 45 * refer to them) 46 * 47 * "size" is the uncompressed object size. Compressed size of the raw 48 * data for an object in a pack is not stored anywhere but is computed 49 * and made available when reverse .idx is made. Note that when a 50 * delta is reused, "size" is the uncompressed _delta_ size, not the 51 * canonical one after the delta has been applied. 52 * 53 * "hash" contains a path name hash which is used for sorting the 54 * delta list and also during delta searching. Once prepare_pack() 55 * returns it's no longer needed. 56 * 57 * source pack info 58 * ---------------- 59 * The (in_pack, in_pack_offset) tuple contains the location of the 60 * object in the source pack. in_pack_header_size allows quickly 61 * skipping the header and going straight to the zlib stream. 62 * 63 * "type" and "in_pack_type" both describe object type. in_pack_type 64 * may contain a delta type, while type is always the canonical type. 65 * 66 * deltas 67 * ------ 68 * Delta links (delta, delta_child and delta_sibling) are created to 69 * reflect that delta graph from the source pack then updated or added 70 * during delta searching phase when we find better deltas. 71 * 72 * delta_child and delta_sibling are last needed in 73 * compute_write_order(). "delta" and "delta_size" must remain valid 74 * at object writing phase in case the delta is not cached. 75 * 76 * If a delta is cached in memory and is compressed, delta_data points 77 * to the data and z_delta_size contains the compressed size. If it's 78 * uncompressed [1], z_delta_size must be zero. delta_size is always 79 * the uncompressed size and must be valid even if the delta is not 80 * cached. 81 * 82 * [1] during try_delta phase we don't bother with compressing because 83 * the delta could be quickly replaced with a better one. 84 */ 85struct object_entry { 86struct pack_idx_entry idx; 87void*delta_data;/* cached delta (uncompressed) */ 88 off_t in_pack_offset; 89uint32_t hash;/* name hint hash */ 90unsigned size_:OE_SIZE_BITS; 91unsigned size_valid:1; 92uint32_t delta_idx;/* delta base object */ 93uint32_t delta_child_idx;/* deltified objects who bases me */ 94uint32_t delta_sibling_idx;/* other deltified objects who 95 * uses the same base as me 96 */ 97unsigned delta_size_:OE_DELTA_SIZE_BITS;/* delta data size (uncompressed) */ 98unsigned delta_size_valid:1; 99unsigned char in_pack_header_size; 100unsigned in_pack_idx:OE_IN_PACK_BITS;/* already in pack */ 101unsigned z_delta_size:OE_Z_DELTA_BITS; 102unsigned type_valid:1; 103unsigned no_try_delta:1; 104unsigned type_:TYPE_BITS; 105unsigned in_pack_type:TYPE_BITS;/* could be delta */ 106unsigned preferred_base:1;/* 107 * we do not pack this, but is available 108 * to be used as the base object to delta 109 * objects against. 110 */ 111unsigned tagged:1;/* near the very tip of refs */ 112unsigned filled:1;/* assigned write-order */ 113unsigned dfs_state:OE_DFS_STATE_BITS; 114unsigned depth:OE_DEPTH_BITS; 115unsigned ext_base:1;/* delta_idx points outside packlist */ 116 117/* 118 * pahole results on 64-bit linux (gcc and clang) 119 * 120 * size: 80, bit_padding: 9 bits 121 * 122 * and on 32-bit (gcc) 123 * 124 * size: 76, bit_padding: 9 bits 125 */ 126}; 127 128struct packing_data { 129struct object_entry *objects; 130uint32_t nr_objects, nr_alloc; 131 132int32_t*index; 133uint32_t index_size; 134 135unsigned int*in_pack_pos; 136unsigned long*delta_size; 137 138/* 139 * Only one of these can be non-NULL and they have different 140 * sizes. if in_pack_by_idx is allocated, oe_in_pack() returns 141 * the pack of an object using in_pack_idx field. If not, 142 * in_pack[] array is used the same way as in_pack_pos[] 143 */ 144struct packed_git **in_pack_by_idx; 145struct packed_git **in_pack; 146 147#ifndef NO_PTHREADS 148 pthread_mutex_t lock; 149#endif 150 151/* 152 * This list contains entries for bases which we know the other side 153 * has (e.g., via reachability bitmaps), but which aren't in our 154 * "objects" list. 155 */ 156struct object_entry *ext_bases; 157uint32_t nr_ext, alloc_ext; 158 159uintmax_t oe_size_limit; 160uintmax_t oe_delta_size_limit; 161}; 162 163voidprepare_packing_data(struct packing_data *pdata); 164 165staticinlinevoidpacking_data_lock(struct packing_data *pdata) 166{ 167#ifndef NO_PTHREADS 168pthread_mutex_lock(&pdata->lock); 169#endif 170} 171staticinlinevoidpacking_data_unlock(struct packing_data *pdata) 172{ 173#ifndef NO_PTHREADS 174pthread_mutex_unlock(&pdata->lock); 175#endif 176} 177 178struct object_entry *packlist_alloc(struct packing_data *pdata, 179const unsigned char*sha1, 180uint32_t index_pos); 181 182struct object_entry *packlist_find(struct packing_data *pdata, 183const unsigned char*sha1, 184uint32_t*index_pos); 185 186staticinlineuint32_tpack_name_hash(const char*name) 187{ 188uint32_t c, hash =0; 189 190if(!name) 191return0; 192 193/* 194 * This effectively just creates a sortable number from the 195 * last sixteen non-whitespace characters. Last characters 196 * count "most", so things that end in ".c" sort together. 197 */ 198while((c = *name++) !=0) { 199if(isspace(c)) 200continue; 201 hash = (hash >>2) + (c <<24); 202} 203return hash; 204} 205 206staticinlineenum object_type oe_type(const struct object_entry *e) 207{ 208return e->type_valid ? e->type_ : OBJ_BAD; 209} 210 211staticinlinevoidoe_set_type(struct object_entry *e, 212enum object_type type) 213{ 214if(type >= OBJ_ANY) 215BUG("OBJ_ANY cannot be set in pack-objects code"); 216 217 e->type_valid = type >= OBJ_NONE; 218 e->type_ = (unsigned)type; 219} 220 221staticinlineunsigned intoe_in_pack_pos(const struct packing_data *pack, 222const struct object_entry *e) 223{ 224return pack->in_pack_pos[e - pack->objects]; 225} 226 227staticinlinevoidoe_set_in_pack_pos(const struct packing_data *pack, 228const struct object_entry *e, 229unsigned int pos) 230{ 231 pack->in_pack_pos[e - pack->objects] = pos; 232} 233 234staticinlinestruct packed_git *oe_in_pack(const struct packing_data *pack, 235const struct object_entry *e) 236{ 237if(pack->in_pack_by_idx) 238return pack->in_pack_by_idx[e->in_pack_idx]; 239else 240return pack->in_pack[e - pack->objects]; 241} 242 243voidoe_map_new_pack(struct packing_data *pack, 244struct packed_git *p); 245staticinlinevoidoe_set_in_pack(struct packing_data *pack, 246struct object_entry *e, 247struct packed_git *p) 248{ 249if(!p->index) 250oe_map_new_pack(pack, p); 251if(pack->in_pack_by_idx) 252 e->in_pack_idx = p->index; 253else 254 pack->in_pack[e - pack->objects] = p; 255} 256 257staticinlinestruct object_entry *oe_delta( 258const struct packing_data *pack, 259const struct object_entry *e) 260{ 261if(!e->delta_idx) 262return NULL; 263if(e->ext_base) 264return&pack->ext_bases[e->delta_idx -1]; 265else 266return&pack->objects[e->delta_idx -1]; 267} 268 269staticinlinevoidoe_set_delta(struct packing_data *pack, 270struct object_entry *e, 271struct object_entry *delta) 272{ 273if(delta) 274 e->delta_idx = (delta - pack->objects) +1; 275else 276 e->delta_idx =0; 277} 278 279voidoe_set_delta_ext(struct packing_data *pack, 280struct object_entry *e, 281const unsigned char*sha1); 282 283staticinlinestruct object_entry *oe_delta_child( 284const struct packing_data *pack, 285const struct object_entry *e) 286{ 287if(e->delta_child_idx) 288return&pack->objects[e->delta_child_idx -1]; 289return NULL; 290} 291 292staticinlinevoidoe_set_delta_child(struct packing_data *pack, 293struct object_entry *e, 294struct object_entry *delta) 295{ 296if(delta) 297 e->delta_child_idx = (delta - pack->objects) +1; 298else 299 e->delta_child_idx =0; 300} 301 302staticinlinestruct object_entry *oe_delta_sibling( 303const struct packing_data *pack, 304const struct object_entry *e) 305{ 306if(e->delta_sibling_idx) 307return&pack->objects[e->delta_sibling_idx -1]; 308return NULL; 309} 310 311staticinlinevoidoe_set_delta_sibling(struct packing_data *pack, 312struct object_entry *e, 313struct object_entry *delta) 314{ 315if(delta) 316 e->delta_sibling_idx = (delta - pack->objects) +1; 317else 318 e->delta_sibling_idx =0; 319} 320 321unsigned longoe_get_size_slow(struct packing_data *pack, 322const struct object_entry *e); 323staticinlineunsigned longoe_size(struct packing_data *pack, 324const struct object_entry *e) 325{ 326if(e->size_valid) 327return e->size_; 328 329returnoe_get_size_slow(pack, e); 330} 331 332staticinlineintoe_size_less_than(struct packing_data *pack, 333const struct object_entry *lhs, 334unsigned long rhs) 335{ 336if(lhs->size_valid) 337return lhs->size_ < rhs; 338if(rhs < pack->oe_size_limit)/* rhs < 2^x <= lhs ? */ 339return0; 340returnoe_get_size_slow(pack, lhs) < rhs; 341} 342 343staticinlineintoe_size_greater_than(struct packing_data *pack, 344const struct object_entry *lhs, 345unsigned long rhs) 346{ 347if(lhs->size_valid) 348return lhs->size_ > rhs; 349if(rhs < pack->oe_size_limit)/* rhs < 2^x <= lhs ? */ 350return1; 351returnoe_get_size_slow(pack, lhs) > rhs; 352} 353 354staticinlinevoidoe_set_size(struct packing_data *pack, 355struct object_entry *e, 356unsigned long size) 357{ 358if(size < pack->oe_size_limit) { 359 e->size_ = size; 360 e->size_valid =1; 361}else{ 362 e->size_valid =0; 363if(oe_get_size_slow(pack, e) != size) 364BUG("'size' is supposed to be the object size!"); 365} 366} 367 368staticinlineunsigned longoe_delta_size(struct packing_data *pack, 369const struct object_entry *e) 370{ 371if(e->delta_size_valid) 372return e->delta_size_; 373 374/* 375 * pack->detla_size[] can't be NULL because oe_set_delta_size() 376 * must have been called when a new delta is saved with 377 * oe_set_delta(). 378 * If oe_delta() returns NULL (i.e. default state, which means 379 * delta_size_valid is also false), then the caller must never 380 * call oe_delta_size(). 381 */ 382return pack->delta_size[e - pack->objects]; 383} 384 385staticinlinevoidoe_set_delta_size(struct packing_data *pack, 386struct object_entry *e, 387unsigned long size) 388{ 389if(size < pack->oe_delta_size_limit) { 390 e->delta_size_ = size; 391 e->delta_size_valid =1; 392}else{ 393packing_data_lock(pack); 394if(!pack->delta_size) 395ALLOC_ARRAY(pack->delta_size, pack->nr_alloc); 396packing_data_unlock(pack); 397 398 pack->delta_size[e - pack->objects] = size; 399 e->delta_size_valid =0; 400} 401} 402 403#endif