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