object-store.h

   1 #ifndef OBJECT_STORE_H
   2 #define OBJECT_STORE_H
   3
   4 #include "cache.h"
   5 #include "oidmap.h"
   6 #include "list.h"
   7 #include "oid-array.h"
   8 #include "strbuf.h"
   9 #include "thread-utils.h"
  10 #include "khash.h"
  11 #include "dir.h"
  12 #include "oidtree.h"
  13 #include "oidset.h"
  14
  15 struct object_directory {
  16         struct object_directory *next;
  17
  18         /*
  19          * Used to store the results of readdir(3) calls when we are OK
  20          * sacrificing accuracy due to races for speed. That includes
  21          * object existence with OBJECT_INFO_QUICK, as well as
  22          * our search for unique abbreviated hashes. Don't use it for tasks
  23          * requiring greater accuracy!
  24          *
  25          * Be sure to call odb_load_loose_cache() before using.
  26          */
  27         uint32_t loose_objects_subdir_seen[8]; /* 256 bits */
  28         struct oidtree *loose_objects_cache;
  29
  30         /*
  31          * Path to the alternative object store. If this is a relative path,
  32          * it is relative to the current working directory.
  33          */
  34         char *path;
  35 };
  36
  37 KHASH_INIT(odb_path_map, const char * /* key: odb_path */,
  38         struct object_directory *, 1, fspathhash, fspatheq)
  39
  40 void prepare_alt_odb(struct repository *r);
  41 char *compute_alternate_path(const char *path, struct strbuf *err);
  42 struct object_directory *find_odb(struct repository *r, const char *obj_dir);
  43 typedef int alt_odb_fn(struct object_directory *, void *);
  44 int foreach_alt_odb(alt_odb_fn, void*);
  45 typedef void alternate_ref_fn(const struct object_id *oid, void *);
  46 void for_each_alternate_ref(alternate_ref_fn, void *);
  47
  48 /*
  49  * Add the directory to the on-disk alternates file; the new entry will also
  50  * take effect in the current process.
  51  */
  52 void add_to_alternates_file(const char *dir);
  53
  54 /*
  55  * Add the directory to the in-memory list of alternates (along with any
  56  * recursive alternates it points to), but do not modify the on-disk alternates
  57  * file.
  58  */
  59 void add_to_alternates_memory(const char *dir);
  60
  61 /*
  62  * Populate and return the loose object cache array corresponding to the
  63  * given object ID.
  64  */
  65 struct oidtree *odb_loose_cache(struct object_directory *odb,
  66                                   const struct object_id *oid);
  67
  68 /* Empty the loose object cache for the specified object directory. */
  69 void odb_clear_loose_cache(struct object_directory *odb);
  70
  71 struct packed_git {
  72         struct hashmap_entry packmap_ent;
  73         struct packed_git *next;
  74         struct list_head mru;
  75         struct pack_window *windows;
  76         off_t pack_size;
  77         const void *index_data;
  78         size_t index_size;
  79         uint32_t num_objects;
  80         uint32_t crc_offset;
  81         struct oidset bad_objects;
  82         int index_version;
  83         time_t mtime;
  84         int pack_fd;
  85         int index;              /* for builtin/pack-objects.c */
  86         unsigned pack_local:1,
  87                  pack_keep:1,
  88                  pack_keep_in_core:1,
  89                  freshened:1,
  90                  do_not_close:1,
  91                  pack_promisor:1,
  92                  multi_pack_index:1;
  93         unsigned char hash[GIT_MAX_RAWSZ];
  94         struct revindex_entry *revindex;
  95         const uint32_t *revindex_data;
  96         const uint32_t *revindex_map;
  97         size_t revindex_size;
  98         /* something like ".git/objects/pack/xxxxx.pack" */
  99         char pack_name[FLEX_ARRAY]; /* more */
 100 };
 101
 102 struct multi_pack_index;
 103
 104 static inline int pack_map_entry_cmp(const void *unused_cmp_data,
 105                                      const struct hashmap_entry *entry,
 106                                      const struct hashmap_entry *entry2,
 107                                      const void *keydata)
 108 {
 109         const char *key = keydata;
 110         const struct packed_git *pg1, *pg2;
 111
 112         pg1 = container_of(entry, const struct packed_git, packmap_ent);
 113         pg2 = container_of(entry2, const struct packed_git, packmap_ent);
 114
 115         return strcmp(pg1->pack_name, key ? key : pg2->pack_name);
 116 }
 117
 118 struct raw_object_store {
 119         /*
 120          * Set of all object directories; the main directory is first (and
 121          * cannot be NULL after initialization). Subsequent directories are
 122          * alternates.
 123          */
 124         struct object_directory *odb;
 125         struct object_directory **odb_tail;
 126         kh_odb_path_map_t *odb_by_path;
 127
 128         int loaded_alternates;
 129
 130         /*
 131          * A list of alternate object directories loaded from the environment;
 132          * this should not generally need to be accessed directly, but will
 133          * populate the "odb" list when prepare_alt_odb() is run.
 134          */
 135         char *alternate_db;
 136
 137         /*
 138          * Objects that should be substituted by other objects
 139          * (see git-replace(1)).
 140          */
 141         struct oidmap *replace_map;
 142         unsigned replace_map_initialized : 1;
 143         pthread_mutex_t replace_mutex; /* protect object replace functions */
 144
 145         struct commit_graph *commit_graph;
 146         unsigned commit_graph_attempted : 1; /* if loading has been attempted */
 147
 148         /*
 149          * private data
 150          *
 151          * should only be accessed directly by packfile.c and midx.c
 152          */
 153         struct multi_pack_index *multi_pack_index;
 154
 155         /*
 156          * private data
 157          *
 158          * should only be accessed directly by packfile.c
 159          */
 160
 161         struct packed_git *packed_git;
 162         /* A most-recently-used ordered version of the packed_git list. */
 163         struct list_head packed_git_mru;
 164
 165         struct {
 166                 struct packed_git **packs;
 167                 unsigned flags;
 168         } kept_pack_cache;
 169
 170         /*
 171          * A map of packfiles to packed_git structs for tracking which
 172          * packs have been loaded already.
 173          */
 174         struct hashmap pack_map;
 175
 176         /*
 177          * A fast, rough count of the number of objects in the repository.
 178          * These two fields are not meant for direct access. Use
 179          * approximate_object_count() instead.
 180          */
 181         unsigned long approximate_object_count;
 182         unsigned approximate_object_count_valid : 1;
 183
 184         /*
 185          * Whether packed_git has already been populated with this repository's
 186          * packs.
 187          */
 188         unsigned packed_git_initialized : 1;
 189 };
 190
 191 struct raw_object_store *raw_object_store_new(void);
 192 void raw_object_store_clear(struct raw_object_store *o);
 193
 194 /*
 195  * Put in `buf` the name of the file in the local object database that
 196  * would be used to store a loose object with the specified oid.
 197  */
 198 const char *loose_object_path(struct repository *r, struct strbuf *buf,
 199                               const struct object_id *oid);
 200
 201 void *map_loose_object(struct repository *r, const struct object_id *oid,
 202                        unsigned long *size);
 203
 204 void *read_object_file_extended(struct repository *r,
 205                                 const struct object_id *oid,
 206                                 enum object_type *type,
 207                                 unsigned long *size, int lookup_replace);
 208 static inline void *repo_read_object_file(struct repository *r,
 209                                           const struct object_id *oid,
 210                                           enum object_type *type,
 211                                           unsigned long *size)
 212 {
 213         return read_object_file_extended(r, oid, type, size, 1);
 214 }
 215 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 216 #define read_object_file(oid, type, size) repo_read_object_file(the_repository, oid, type, size)
 217 #endif
 218
 219 /* Read and unpack an object file into memory, write memory to an object file */
 220 int oid_object_info(struct repository *r, const struct object_id *, unsigned long *);
 221
 222 int hash_object_file(const struct git_hash_algo *algo, const void *buf,
 223                      unsigned long len, const char *type,
 224                      struct object_id *oid);
 225
 226 int write_object_file_flags(const void *buf, unsigned long len,
 227                             const char *type, struct object_id *oid,
 228                             unsigned flags);
 229 static inline int write_object_file(const void *buf, unsigned long len,
 230                                     const char *type, struct object_id *oid)
 231 {
 232         return write_object_file_flags(buf, len, type, oid, 0);
 233 }
 234
 235 int hash_object_file_literally(const void *buf, unsigned long len,
 236                                const char *type, struct object_id *oid,
 237                                unsigned flags);
 238
 239 /*
 240  * Add an object file to the in-memory object store, without writing it
 241  * to disk.
 242  *
 243  * Callers are responsible for calling write_object_file to record the
 244  * object in persistent storage before writing any other new objects
 245  * that reference it.
 246  */
 247 int pretend_object_file(void *, unsigned long, enum object_type,
 248                         struct object_id *oid);
 249
 250 int force_object_loose(const struct object_id *oid, time_t mtime);
 251
 252 /*
 253  * Open the loose object at path, check its hash, and return the contents,
 254  * use the "oi" argument to assert things about the object, or e.g. populate its
 255  * type, and size. If the object is a blob, then "contents" may return NULL,
 256  * to allow streaming of large blobs.
 257  *
 258  * Returns 0 on success, negative on error (details may be written to stderr).
 259  */
 260 int read_loose_object(const char *path,
 261                       const struct object_id *expected_oid,
 262                       struct object_id *real_oid,
 263                       void **contents,
 264                       struct object_info *oi);
 265
 266 /* Retry packed storage after checking packed and loose storage */
 267 #define HAS_OBJECT_RECHECK_PACKED 1
 268
 269 /*
 270  * Returns 1 if the object exists. This function will not lazily fetch objects
 271  * in a partial clone.
 272  */
 273 int has_object(struct repository *r, const struct object_id *oid,
 274                unsigned flags);
 275
 276 /*
 277  * These macros and functions are deprecated. If checking existence for an
 278  * object that is likely to be missing and/or whose absence is relatively
 279  * inconsequential (or is consequential but the caller is prepared to handle
 280  * it), use has_object(), which has better defaults (no lazy fetch in a partial
 281  * clone and no rechecking of packed storage). In the unlikely event that a
 282  * caller needs to assert existence of an object that it fully expects to
 283  * exist, and wants to trigger a lazy fetch in a partial clone, use
 284  * oid_object_info_extended() with a NULL struct object_info.
 285  *
 286  * These functions can be removed once all callers have migrated to
 287  * has_object() and/or oid_object_info_extended().
 288  */
 289 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 290 #define has_sha1_file_with_flags(sha1, flags) repo_has_sha1_file_with_flags(the_repository, sha1, flags)
 291 #define has_sha1_file(sha1) repo_has_sha1_file(the_repository, sha1)
 292 #endif
 293 int repo_has_object_file(struct repository *r, const struct object_id *oid);
 294 int repo_has_object_file_with_flags(struct repository *r,
 295                                     const struct object_id *oid, int flags);
 296 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 297 #define has_object_file(oid) repo_has_object_file(the_repository, oid)
 298 #define has_object_file_with_flags(oid, flags) repo_has_object_file_with_flags(the_repository, oid, flags)
 299 #endif
 300
 301 /*
 302  * Return true iff an alternate object database has a loose object
 303  * with the specified name.  This function does not respect replace
 304  * references.
 305  */
 306 int has_loose_object_nonlocal(const struct object_id *);
 307
 308 void assert_oid_type(const struct object_id *oid, enum object_type expect);
 309
 310 /*
 311  * Enabling the object read lock allows multiple threads to safely call the
 312  * following functions in parallel: repo_read_object_file(), read_object_file(),
 313  * read_object_file_extended(), read_object_with_reference(), read_object(),
 314  * oid_object_info() and oid_object_info_extended().
 315  *
 316  * obj_read_lock() and obj_read_unlock() may also be used to protect other
 317  * section which cannot execute in parallel with object reading. Since the used
 318  * lock is a recursive mutex, these sections can even contain calls to object
 319  * reading functions. However, beware that in these cases zlib inflation won't
 320  * be performed in parallel, losing performance.
 321  *
 322  * TODO: oid_object_info_extended()'s call stack has a recursive behavior. If
 323  * any of its callees end up calling it, this recursive call won't benefit from
 324  * parallel inflation.
 325  */
 326 void enable_obj_read_lock(void);
 327 void disable_obj_read_lock(void);
 328
 329 extern int obj_read_use_lock;
 330 extern pthread_mutex_t obj_read_mutex;
 331
 332 static inline void obj_read_lock(void)
 333 {
 334         if(obj_read_use_lock)
 335                 pthread_mutex_lock(&obj_read_mutex);
 336 }
 337
 338 static inline void obj_read_unlock(void)
 339 {
 340         if(obj_read_use_lock)
 341                 pthread_mutex_unlock(&obj_read_mutex);
 342 }
 343
 344 struct object_info {
 345         /* Request */
 346         enum object_type *typep;
 347         unsigned long *sizep;
 348         off_t *disk_sizep;
 349         struct object_id *delta_base_oid;
 350         struct strbuf *type_name;
 351         void **contentp;
 352
 353         /* Response */
 354         enum {
 355                 OI_CACHED,
 356                 OI_LOOSE,
 357                 OI_PACKED,
 358                 OI_DBCACHED
 359         } whence;
 360         union {
 361                 /*
 362                  * struct {
 363                  *      ... Nothing to expose in this case
 364                  * } cached;
 365                  * struct {
 366                  *      ... Nothing to expose in this case
 367                  * } loose;
 368                  */
 369                 struct {
 370                         struct packed_git *pack;
 371                         off_t offset;
 372                         unsigned int is_delta;
 373                 } packed;
 374         } u;
 375 };
 376
 377 /*
 378  * Initializer for a "struct object_info" that wants no items. You may
 379  * also memset() the memory to all-zeroes.
 380  */
 381 #define OBJECT_INFO_INIT { 0 }
 382
 383 /* Invoke lookup_replace_object() on the given hash */
 384 #define OBJECT_INFO_LOOKUP_REPLACE 1
 385 /* Allow reading from a loose object file of unknown/bogus type */
 386 #define OBJECT_INFO_ALLOW_UNKNOWN_TYPE 2
 387 /* Do not retry packed storage after checking packed and loose storage */
 388 #define OBJECT_INFO_QUICK 8
 389 /* Do not check loose object */
 390 #define OBJECT_INFO_IGNORE_LOOSE 16
 391 /*
 392  * Do not attempt to fetch the object if missing (even if fetch_is_missing is
 393  * nonzero).
 394  */
 395 #define OBJECT_INFO_SKIP_FETCH_OBJECT 32
 396 /*
 397  * This is meant for bulk prefetching of missing blobs in a partial
 398  * clone. Implies OBJECT_INFO_SKIP_FETCH_OBJECT and OBJECT_INFO_QUICK
 399  */
 400 #define OBJECT_INFO_FOR_PREFETCH (OBJECT_INFO_SKIP_FETCH_OBJECT | OBJECT_INFO_QUICK)
 401
 402 int oid_object_info_extended(struct repository *r,
 403                              const struct object_id *,
 404                              struct object_info *, unsigned flags);
 405
 406 /*
 407  * Iterate over the files in the loose-object parts of the object
 408  * directory "path", triggering the following callbacks:
 409  *
 410  *  - loose_object is called for each loose object we find.
 411  *
 412  *  - loose_cruft is called for any files that do not appear to be
 413  *    loose objects. Note that we only look in the loose object
 414  *    directories "objects/[0-9a-f]{2}/", so we will not report
 415  *    "objects/foobar" as cruft.
 416  *
 417  *  - loose_subdir is called for each top-level hashed subdirectory
 418  *    of the object directory (e.g., "$OBJDIR/f0"). It is called
 419  *    after the objects in the directory are processed.
 420  *
 421  * Any callback that is NULL will be ignored. Callbacks returning non-zero
 422  * will end the iteration.
 423  *
 424  * In the "buf" variant, "path" is a strbuf which will also be used as a
 425  * scratch buffer, but restored to its original contents before
 426  * the function returns.
 427  */
 428 typedef int each_loose_object_fn(const struct object_id *oid,
 429                                  const char *path,
 430                                  void *data);
 431 typedef int each_loose_cruft_fn(const char *basename,
 432                                 const char *path,
 433                                 void *data);
 434 typedef int each_loose_subdir_fn(unsigned int nr,
 435                                  const char *path,
 436                                  void *data);
 437 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
 438                                 struct strbuf *path,
 439                                 each_loose_object_fn obj_cb,
 440                                 each_loose_cruft_fn cruft_cb,
 441                                 each_loose_subdir_fn subdir_cb,
 442                                 void *data);
 443 int for_each_loose_file_in_objdir(const char *path,
 444                                   each_loose_object_fn obj_cb,
 445                                   each_loose_cruft_fn cruft_cb,
 446                                   each_loose_subdir_fn subdir_cb,
 447                                   void *data);
 448 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
 449                                       each_loose_object_fn obj_cb,
 450                                       each_loose_cruft_fn cruft_cb,
 451                                       each_loose_subdir_fn subdir_cb,
 452                                       void *data);
 453
 454 /* Flags for for_each_*_object() below. */
 455 enum for_each_object_flags {
 456         /* Iterate only over local objects, not alternates. */
 457         FOR_EACH_OBJECT_LOCAL_ONLY = (1<<0),
 458
 459         /* Only iterate over packs obtained from the promisor remote. */
 460         FOR_EACH_OBJECT_PROMISOR_ONLY = (1<<1),
 461
 462         /*
 463          * Visit objects within a pack in packfile order rather than .idx order
 464          */
 465         FOR_EACH_OBJECT_PACK_ORDER = (1<<2),
 466
 467         /* Only iterate over packs that are not marked as kept in-core. */
 468         FOR_EACH_OBJECT_SKIP_IN_CORE_KEPT_PACKS = (1<<3),
 469
 470         /* Only iterate over packs that do not have .keep files. */
 471         FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS = (1<<4),
 472 };
 473
 474 /*
 475  * Iterate over all accessible loose objects without respect to
 476  * reachability. By default, this includes both local and alternate objects.
 477  * The order in which objects are visited is unspecified.
 478  *
 479  * Any flags specific to packs are ignored.
 480  */
 481 int for_each_loose_object(each_loose_object_fn, void *,
 482                           enum for_each_object_flags flags);
 483
 484 /*
 485  * Iterate over all accessible packed objects without respect to reachability.
 486  * By default, this includes both local and alternate packs.
 487  *
 488  * Note that some objects may appear twice if they are found in multiple packs.
 489  * Each pack is visited in an unspecified order. By default, objects within a
 490  * pack are visited in pack-idx order (i.e., sorted by oid).
 491  */
 492 typedef int each_packed_object_fn(const struct object_id *oid,
 493                                   struct packed_git *pack,
 494                                   uint32_t pos,
 495                                   void *data);
 496 int for_each_object_in_pack(struct packed_git *p,
 497                             each_packed_object_fn, void *data,
 498                             enum for_each_object_flags flags);
 499 int for_each_packed_object(each_packed_object_fn, void *,
 500                            enum for_each_object_flags flags);
 501
 502 #endif /* OBJECT_STORE_H */