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
  14 struct object_directory {
  15         struct object_directory *next;
  16
  17         /*
  18          * Used to store the results of readdir(3) calls when we are OK
  19          * sacrificing accuracy due to races for speed. That includes
  20          * object existence with OBJECT_INFO_QUICK, as well as
  21          * our search for unique abbreviated hashes. Don't use it for tasks
  22          * requiring greater accuracy!
  23          *
  24          * Be sure to call odb_load_loose_cache() before using.
  25          */
  26         uint32_t loose_objects_subdir_seen[8]; /* 256 bits */
  27         struct oidtree *loose_objects_cache;
  28
  29         /*
  30          * Path to the alternative object store. If this is a relative path,
  31          * it is relative to the current working directory.
  32          */
  33         char *path;
  34 };
  35
  36 KHASH_INIT(odb_path_map, const char * /* key: odb_path */,
  37         struct object_directory *, 1, fspathhash, fspatheq)
  38
  39 void prepare_alt_odb(struct repository *r);
  40 char *compute_alternate_path(const char *path, struct strbuf *err);
  41 typedef int alt_odb_fn(struct object_directory *, void *);
  42 int foreach_alt_odb(alt_odb_fn, void*);
  43 typedef void alternate_ref_fn(const struct object_id *oid, void *);
  44 void for_each_alternate_ref(alternate_ref_fn, void *);
  45
  46 /*
  47  * Add the directory to the on-disk alternates file; the new entry will also
  48  * take effect in the current process.
  49  */
  50 void add_to_alternates_file(const char *dir);
  51
  52 /*
  53  * Add the directory to the in-memory list of alternates (along with any
  54  * recursive alternates it points to), but do not modify the on-disk alternates
  55  * file.
  56  */
  57 void add_to_alternates_memory(const char *dir);
  58
  59 /*
  60  * Populate and return the loose object cache array corresponding to the
  61  * given object ID.
  62  */
  63 struct oidtree *odb_loose_cache(struct object_directory *odb,
  64                                   const struct object_id *oid);
  65
  66 /* Empty the loose object cache for the specified object directory. */
  67 void odb_clear_loose_cache(struct object_directory *odb);
  68
  69 struct packed_git {
  70         struct hashmap_entry packmap_ent;
  71         struct packed_git *next;
  72         struct list_head mru;
  73         struct pack_window *windows;
  74         off_t pack_size;
  75         const void *index_data;
  76         size_t index_size;
  77         uint32_t num_objects;
  78         uint32_t num_bad_objects;
  79         uint32_t crc_offset;
  80         unsigned char *bad_object_sha1;
  81         int index_version;
  82         time_t mtime;
  83         int pack_fd;
  84         int index;              /* for builtin/pack-objects.c */
  85         unsigned pack_local:1,
  86                  pack_keep:1,
  87                  pack_keep_in_core:1,
  88                  freshened:1,
  89                  do_not_close:1,
  90                  pack_promisor:1,
  91                  multi_pack_index:1;
  92         unsigned char hash[GIT_MAX_RAWSZ];
  93         struct revindex_entry *revindex;
  94         const uint32_t *revindex_data;
  95         const uint32_t *revindex_map;
  96         size_t revindex_size;
  97         /* something like ".git/objects/pack/xxxxx.pack" */
  98         char pack_name[FLEX_ARRAY]; /* more */
  99 };
 100
 101 struct multi_pack_index;
 102
 103 static inline int pack_map_entry_cmp(const void *unused_cmp_data,
 104                                      const struct hashmap_entry *entry,
 105                                      const struct hashmap_entry *entry2,
 106                                      const void *keydata)
 107 {
 108         const char *key = keydata;
 109         const struct packed_git *pg1, *pg2;
 110
 111         pg1 = container_of(entry, const struct packed_git, packmap_ent);
 112         pg2 = container_of(entry2, const struct packed_git, packmap_ent);
 113
 114         return strcmp(pg1->pack_name, key ? key : pg2->pack_name);
 115 }
 116
 117 struct raw_object_store {
 118         /*
 119          * Set of all object directories; the main directory is first (and
 120          * cannot be NULL after initialization). Subsequent directories are
 121          * alternates.
 122          */
 123         struct object_directory *odb;
 124         struct object_directory **odb_tail;
 125         kh_odb_path_map_t *odb_by_path;
 126
 127         int loaded_alternates;
 128
 129         /*
 130          * A list of alternate object directories loaded from the environment;
 131          * this should not generally need to be accessed directly, but will
 132          * populate the "odb" list when prepare_alt_odb() is run.
 133          */
 134         char *alternate_db;
 135
 136         /*
 137          * Objects that should be substituted by other objects
 138          * (see git-replace(1)).
 139          */
 140         struct oidmap *replace_map;
 141         unsigned replace_map_initialized : 1;
 142         pthread_mutex_t replace_mutex; /* protect object replace functions */
 143
 144         struct commit_graph *commit_graph;
 145         unsigned commit_graph_attempted : 1; /* if loading has been attempted */
 146
 147         /*
 148          * private data
 149          *
 150          * should only be accessed directly by packfile.c and midx.c
 151          */
 152         struct multi_pack_index *multi_pack_index;
 153
 154         /*
 155          * private data
 156          *
 157          * should only be accessed directly by packfile.c
 158          */
 159
 160         struct packed_git *packed_git;
 161         /* A most-recently-used ordered version of the packed_git list. */
 162         struct list_head packed_git_mru;
 163
 164         struct {
 165                 struct packed_git **packs;
 166                 unsigned flags;
 167         } kept_pack_cache;
 168
 169         /*
 170          * A map of packfiles to packed_git structs for tracking which
 171          * packs have been loaded already.
 172          */
 173         struct hashmap pack_map;
 174
 175         /*
 176          * A fast, rough count of the number of objects in the repository.
 177          * These two fields are not meant for direct access. Use
 178          * approximate_object_count() instead.
 179          */
 180         unsigned long approximate_object_count;
 181         unsigned approximate_object_count_valid : 1;
 182
 183         /*
 184          * Whether packed_git has already been populated with this repository's
 185          * packs.
 186          */
 187         unsigned packed_git_initialized : 1;
 188 };
 189
 190 struct raw_object_store *raw_object_store_new(void);
 191 void raw_object_store_clear(struct raw_object_store *o);
 192
 193 /*
 194  * Put in `buf` the name of the file in the local object database that
 195  * would be used to store a loose object with the specified oid.
 196  */
 197 const char *loose_object_path(struct repository *r, struct strbuf *buf,
 198                               const struct object_id *oid);
 199
 200 void *map_loose_object(struct repository *r, const struct object_id *oid,
 201                        unsigned long *size);
 202
 203 void *read_object_file_extended(struct repository *r,
 204                                 const struct object_id *oid,
 205                                 enum object_type *type,
 206                                 unsigned long *size, int lookup_replace);
 207 static inline void *repo_read_object_file(struct repository *r,
 208                                           const struct object_id *oid,
 209                                           enum object_type *type,
 210                                           unsigned long *size)
 211 {
 212         return read_object_file_extended(r, oid, type, size, 1);
 213 }
 214 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 215 #define read_object_file(oid, type, size) repo_read_object_file(the_repository, oid, type, size)
 216 #endif
 217
 218 /* Read and unpack an object file into memory, write memory to an object file */
 219 int oid_object_info(struct repository *r, const struct object_id *, unsigned long *);
 220
 221 int hash_object_file(const struct git_hash_algo *algo, const void *buf,
 222                      unsigned long len, const char *type,
 223                      struct object_id *oid);
 224
 225 int write_object_file(const void *buf, unsigned long len,
 226                       const char *type, struct object_id *oid);
 227
 228 int hash_object_file_literally(const void *buf, unsigned long len,
 229                                const char *type, struct object_id *oid,
 230                                unsigned flags);
 231
 232 /*
 233  * Add an object file to the in-memory object store, without writing it
 234  * to disk.
 235  *
 236  * Callers are responsible for calling write_object_file to record the
 237  * object in persistent storage before writing any other new objects
 238  * that reference it.
 239  */
 240 int pretend_object_file(void *, unsigned long, enum object_type,
 241                         struct object_id *oid);
 242
 243 int force_object_loose(const struct object_id *oid, time_t mtime);
 244
 245 /*
 246  * Open the loose object at path, check its hash, and return the contents,
 247  * type, and size. If the object is a blob, then "contents" may return NULL,
 248  * to allow streaming of large blobs.
 249  *
 250  * Returns 0 on success, negative on error (details may be written to stderr).
 251  */
 252 int read_loose_object(const char *path,
 253                       const struct object_id *expected_oid,
 254                       enum object_type *type,
 255                       unsigned long *size,
 256                       void **contents);
 257
 258 /* Retry packed storage after checking packed and loose storage */
 259 #define HAS_OBJECT_RECHECK_PACKED 1
 260
 261 /*
 262  * Returns 1 if the object exists. This function will not lazily fetch objects
 263  * in a partial clone.
 264  */
 265 int has_object(struct repository *r, const struct object_id *oid,
 266                unsigned flags);
 267
 268 /*
 269  * These macros and functions are deprecated. If checking existence for an
 270  * object that is likely to be missing and/or whose absence is relatively
 271  * inconsequential (or is consequential but the caller is prepared to handle
 272  * it), use has_object(), which has better defaults (no lazy fetch in a partial
 273  * clone and no rechecking of packed storage). In the unlikely event that a
 274  * caller needs to assert existence of an object that it fully expects to
 275  * exist, and wants to trigger a lazy fetch in a partial clone, use
 276  * oid_object_info_extended() with a NULL struct object_info.
 277  *
 278  * These functions can be removed once all callers have migrated to
 279  * has_object() and/or oid_object_info_extended().
 280  */
 281 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 282 #define has_sha1_file_with_flags(sha1, flags) repo_has_sha1_file_with_flags(the_repository, sha1, flags)
 283 #define has_sha1_file(sha1) repo_has_sha1_file(the_repository, sha1)
 284 #endif
 285 int repo_has_object_file(struct repository *r, const struct object_id *oid);
 286 int repo_has_object_file_with_flags(struct repository *r,
 287                                     const struct object_id *oid, int flags);
 288 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 289 #define has_object_file(oid) repo_has_object_file(the_repository, oid)
 290 #define has_object_file_with_flags(oid, flags) repo_has_object_file_with_flags(the_repository, oid, flags)
 291 #endif
 292
 293 /*
 294  * Return true iff an alternate object database has a loose object
 295  * with the specified name.  This function does not respect replace
 296  * references.
 297  */
 298 int has_loose_object_nonlocal(const struct object_id *);
 299
 300 void assert_oid_type(const struct object_id *oid, enum object_type expect);
 301
 302 /*
 303  * Enabling the object read lock allows multiple threads to safely call the
 304  * following functions in parallel: repo_read_object_file(), read_object_file(),
 305  * read_object_file_extended(), read_object_with_reference(), read_object(),
 306  * oid_object_info() and oid_object_info_extended().
 307  *
 308  * obj_read_lock() and obj_read_unlock() may also be used to protect other
 309  * section which cannot execute in parallel with object reading. Since the used
 310  * lock is a recursive mutex, these sections can even contain calls to object
 311  * reading functions. However, beware that in these cases zlib inflation won't
 312  * be performed in parallel, losing performance.
 313  *
 314  * TODO: oid_object_info_extended()'s call stack has a recursive behavior. If
 315  * any of its callees end up calling it, this recursive call won't benefit from
 316  * parallel inflation.
 317  */
 318 void enable_obj_read_lock(void);
 319 void disable_obj_read_lock(void);
 320
 321 extern int obj_read_use_lock;
 322 extern pthread_mutex_t obj_read_mutex;
 323
 324 static inline void obj_read_lock(void)
 325 {
 326         if(obj_read_use_lock)
 327                 pthread_mutex_lock(&obj_read_mutex);
 328 }
 329
 330 static inline void obj_read_unlock(void)
 331 {
 332         if(obj_read_use_lock)
 333                 pthread_mutex_unlock(&obj_read_mutex);
 334 }
 335
 336 struct object_info {
 337         /* Request */
 338         enum object_type *typep;
 339         unsigned long *sizep;
 340         off_t *disk_sizep;
 341         struct object_id *delta_base_oid;
 342         struct strbuf *type_name;
 343         void **contentp;
 344
 345         /* Response */
 346         enum {
 347                 OI_CACHED,
 348                 OI_LOOSE,
 349                 OI_PACKED,
 350                 OI_DBCACHED
 351         } whence;
 352         union {
 353                 /*
 354                  * struct {
 355                  *      ... Nothing to expose in this case
 356                  * } cached;
 357                  * struct {
 358                  *      ... Nothing to expose in this case
 359                  * } loose;
 360                  */
 361                 struct {
 362                         struct packed_git *pack;
 363                         off_t offset;
 364                         unsigned int is_delta;
 365                 } packed;
 366         } u;
 367 };
 368
 369 /*
 370  * Initializer for a "struct object_info" that wants no items. You may
 371  * also memset() the memory to all-zeroes.
 372  */
 373 #define OBJECT_INFO_INIT {NULL}
 374
 375 /* Invoke lookup_replace_object() on the given hash */
 376 #define OBJECT_INFO_LOOKUP_REPLACE 1
 377 /* Allow reading from a loose object file of unknown/bogus type */
 378 #define OBJECT_INFO_ALLOW_UNKNOWN_TYPE 2
 379 /* Do not retry packed storage after checking packed and loose storage */
 380 #define OBJECT_INFO_QUICK 8
 381 /* Do not check loose object */
 382 #define OBJECT_INFO_IGNORE_LOOSE 16
 383 /*
 384  * Do not attempt to fetch the object if missing (even if fetch_is_missing is
 385  * nonzero).
 386  */
 387 #define OBJECT_INFO_SKIP_FETCH_OBJECT 32
 388 /*
 389  * This is meant for bulk prefetching of missing blobs in a partial
 390  * clone. Implies OBJECT_INFO_SKIP_FETCH_OBJECT and OBJECT_INFO_QUICK
 391  */
 392 #define OBJECT_INFO_FOR_PREFETCH (OBJECT_INFO_SKIP_FETCH_OBJECT | OBJECT_INFO_QUICK)
 393
 394 int oid_object_info_extended(struct repository *r,
 395                              const struct object_id *,
 396                              struct object_info *, unsigned flags);
 397
 398 /*
 399  * Iterate over the files in the loose-object parts of the object
 400  * directory "path", triggering the following callbacks:
 401  *
 402  *  - loose_object is called for each loose object we find.
 403  *
 404  *  - loose_cruft is called for any files that do not appear to be
 405  *    loose objects. Note that we only look in the loose object
 406  *    directories "objects/[0-9a-f]{2}/", so we will not report
 407  *    "objects/foobar" as cruft.
 408  *
 409  *  - loose_subdir is called for each top-level hashed subdirectory
 410  *    of the object directory (e.g., "$OBJDIR/f0"). It is called
 411  *    after the objects in the directory are processed.
 412  *
 413  * Any callback that is NULL will be ignored. Callbacks returning non-zero
 414  * will end the iteration.
 415  *
 416  * In the "buf" variant, "path" is a strbuf which will also be used as a
 417  * scratch buffer, but restored to its original contents before
 418  * the function returns.
 419  */
 420 typedef int each_loose_object_fn(const struct object_id *oid,
 421                                  const char *path,
 422                                  void *data);
 423 typedef int each_loose_cruft_fn(const char *basename,
 424                                 const char *path,
 425                                 void *data);
 426 typedef int each_loose_subdir_fn(unsigned int nr,
 427                                  const char *path,
 428                                  void *data);
 429 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
 430                                 struct strbuf *path,
 431                                 each_loose_object_fn obj_cb,
 432                                 each_loose_cruft_fn cruft_cb,
 433                                 each_loose_subdir_fn subdir_cb,
 434                                 void *data);
 435 int for_each_loose_file_in_objdir(const char *path,
 436                                   each_loose_object_fn obj_cb,
 437                                   each_loose_cruft_fn cruft_cb,
 438                                   each_loose_subdir_fn subdir_cb,
 439                                   void *data);
 440 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
 441                                       each_loose_object_fn obj_cb,
 442                                       each_loose_cruft_fn cruft_cb,
 443                                       each_loose_subdir_fn subdir_cb,
 444                                       void *data);
 445
 446 /* Flags for for_each_*_object() below. */
 447 enum for_each_object_flags {
 448         /* Iterate only over local objects, not alternates. */
 449         FOR_EACH_OBJECT_LOCAL_ONLY = (1<<0),
 450
 451         /* Only iterate over packs obtained from the promisor remote. */
 452         FOR_EACH_OBJECT_PROMISOR_ONLY = (1<<1),
 453
 454         /*
 455          * Visit objects within a pack in packfile order rather than .idx order
 456          */
 457         FOR_EACH_OBJECT_PACK_ORDER = (1<<2),
 458 };
 459
 460 /*
 461  * Iterate over all accessible loose objects without respect to
 462  * reachability. By default, this includes both local and alternate objects.
 463  * The order in which objects are visited is unspecified.
 464  *
 465  * Any flags specific to packs are ignored.
 466  */
 467 int for_each_loose_object(each_loose_object_fn, void *,
 468                           enum for_each_object_flags flags);
 469
 470 /*
 471  * Iterate over all accessible packed objects without respect to reachability.
 472  * By default, this includes both local and alternate packs.
 473  *
 474  * Note that some objects may appear twice if they are found in multiple packs.
 475  * Each pack is visited in an unspecified order. By default, objects within a
 476  * pack are visited in pack-idx order (i.e., sorted by oid).
 477  */
 478 typedef int each_packed_object_fn(const struct object_id *oid,
 479                                   struct packed_git *pack,
 480                                   uint32_t pos,
 481                                   void *data);
 482 int for_each_object_in_pack(struct packed_git *p,
 483                             each_packed_object_fn, void *data,
 484                             enum for_each_object_flags flags);
 485 int for_each_packed_object(each_packed_object_fn, void *,
 486                            enum for_each_object_flags flags);
 487
 488 #endif /* OBJECT_STORE_H */