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
  11 struct object_directory {
  12         struct object_directory *next;
  13
  14         /*
  15          * Used to store the results of readdir(3) calls when we are OK
  16          * sacrificing accuracy due to races for speed. That includes
  17          * object existence with OBJECT_INFO_QUICK, as well as
  18          * our search for unique abbreviated hashes. Don't use it for tasks
  19          * requiring greater accuracy!
  20          *
  21          * Be sure to call odb_load_loose_cache() before using.
  22          */
  23         char loose_objects_subdir_seen[256];
  24         struct oid_array loose_objects_cache[256];
  25
  26         /*
  27          * Path to the alternative object store. If this is a relative path,
  28          * it is relative to the current working directory.
  29          */
  30         char *path;
  31 };
  32
  33 void prepare_alt_odb(struct repository *r);
  34 char *compute_alternate_path(const char *path, struct strbuf *err);
  35 typedef int alt_odb_fn(struct object_directory *, void *);
  36 int foreach_alt_odb(alt_odb_fn, void*);
  37 typedef void alternate_ref_fn(const struct object_id *oid, void *);
  38 void for_each_alternate_ref(alternate_ref_fn, void *);
  39
  40 /*
  41  * Add the directory to the on-disk alternates file; the new entry will also
  42  * take effect in the current process.
  43  */
  44 void add_to_alternates_file(const char *dir);
  45
  46 /*
  47  * Add the directory to the in-memory list of alternates (along with any
  48  * recursive alternates it points to), but do not modify the on-disk alternates
  49  * file.
  50  */
  51 void add_to_alternates_memory(const char *dir);
  52
  53 /*
  54  * Populate and return the loose object cache array corresponding to the
  55  * given object ID.
  56  */
  57 struct oid_array *odb_loose_cache(struct object_directory *odb,
  58                                   const struct object_id *oid);
  59
  60 /* Empty the loose object cache for the specified object directory. */
  61 void odb_clear_loose_cache(struct object_directory *odb);
  62
  63 struct packed_git {
  64         struct hashmap_entry packmap_ent;
  65         struct packed_git *next;
  66         struct list_head mru;
  67         struct pack_window *windows;
  68         off_t pack_size;
  69         const void *index_data;
  70         size_t index_size;
  71         uint32_t num_objects;
  72         uint32_t num_bad_objects;
  73         uint32_t crc_offset;
  74         unsigned char *bad_object_sha1;
  75         int index_version;
  76         time_t mtime;
  77         int pack_fd;
  78         int index;              /* for builtin/pack-objects.c */
  79         unsigned pack_local:1,
  80                  pack_keep:1,
  81                  pack_keep_in_core:1,
  82                  freshened:1,
  83                  do_not_close:1,
  84                  pack_promisor:1,
  85                  multi_pack_index:1;
  86         unsigned char hash[GIT_MAX_RAWSZ];
  87         struct revindex_entry *revindex;
  88         const uint32_t *revindex_data;
  89         const uint32_t *revindex_map;
  90         size_t revindex_size;
  91         /* something like ".git/objects/pack/xxxxx.pack" */
  92         char pack_name[FLEX_ARRAY]; /* more */
  93 };
  94
  95 struct multi_pack_index;
  96
  97 static inline int pack_map_entry_cmp(const void *unused_cmp_data,
  98                                      const struct hashmap_entry *entry,
  99                                      const struct hashmap_entry *entry2,
 100                                      const void *keydata)
 101 {
 102         const char *key = keydata;
 103         const struct packed_git *pg1, *pg2;
 104
 105         pg1 = container_of(entry, const struct packed_git, packmap_ent);
 106         pg2 = container_of(entry2, const struct packed_git, packmap_ent);
 107
 108         return strcmp(pg1->pack_name, key ? key : pg2->pack_name);
 109 }
 110
 111 struct raw_object_store {
 112         /*
 113          * Set of all object directories; the main directory is first (and
 114          * cannot be NULL after initialization). Subsequent directories are
 115          * alternates.
 116          */
 117         struct object_directory *odb;
 118         struct object_directory **odb_tail;
 119         int loaded_alternates;
 120
 121         /*
 122          * A list of alternate object directories loaded from the environment;
 123          * this should not generally need to be accessed directly, but will
 124          * populate the "odb" list when prepare_alt_odb() is run.
 125          */
 126         char *alternate_db;
 127
 128         /*
 129          * Objects that should be substituted by other objects
 130          * (see git-replace(1)).
 131          */
 132         struct oidmap *replace_map;
 133         unsigned replace_map_initialized : 1;
 134         pthread_mutex_t replace_mutex; /* protect object replace functions */
 135
 136         struct commit_graph *commit_graph;
 137         unsigned commit_graph_attempted : 1; /* if loading has been attempted */
 138
 139         /*
 140          * private data
 141          *
 142          * should only be accessed directly by packfile.c and midx.c
 143          */
 144         struct multi_pack_index *multi_pack_index;
 145
 146         /*
 147          * private data
 148          *
 149          * should only be accessed directly by packfile.c
 150          */
 151
 152         struct packed_git *packed_git;
 153         /* A most-recently-used ordered version of the packed_git list. */
 154         struct list_head packed_git_mru;
 155
 156         struct {
 157                 struct packed_git **packs;
 158                 unsigned flags;
 159         } kept_pack_cache;
 160
 161         /*
 162          * A map of packfiles to packed_git structs for tracking which
 163          * packs have been loaded already.
 164          */
 165         struct hashmap pack_map;
 166
 167         /*
 168          * A fast, rough count of the number of objects in the repository.
 169          * These two fields are not meant for direct access. Use
 170          * approximate_object_count() instead.
 171          */
 172         unsigned long approximate_object_count;
 173         unsigned approximate_object_count_valid : 1;
 174
 175         /*
 176          * Whether packed_git has already been populated with this repository's
 177          * packs.
 178          */
 179         unsigned packed_git_initialized : 1;
 180 };
 181
 182 struct raw_object_store *raw_object_store_new(void);
 183 void raw_object_store_clear(struct raw_object_store *o);
 184
 185 /*
 186  * Put in `buf` the name of the file in the local object database that
 187  * would be used to store a loose object with the specified oid.
 188  */
 189 const char *loose_object_path(struct repository *r, struct strbuf *buf,
 190                               const struct object_id *oid);
 191
 192 void *map_loose_object(struct repository *r, const struct object_id *oid,
 193                        unsigned long *size);
 194
 195 void *read_object_file_extended(struct repository *r,
 196                                 const struct object_id *oid,
 197                                 enum object_type *type,
 198                                 unsigned long *size, int lookup_replace);
 199 static inline void *repo_read_object_file(struct repository *r,
 200                                           const struct object_id *oid,
 201                                           enum object_type *type,
 202                                           unsigned long *size)
 203 {
 204         return read_object_file_extended(r, oid, type, size, 1);
 205 }
 206 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 207 #define read_object_file(oid, type, size) repo_read_object_file(the_repository, oid, type, size)
 208 #endif
 209
 210 /* Read and unpack an object file into memory, write memory to an object file */
 211 int oid_object_info(struct repository *r, const struct object_id *, unsigned long *);
 212
 213 int hash_object_file(const struct git_hash_algo *algo, const void *buf,
 214                      unsigned long len, const char *type,
 215                      struct object_id *oid);
 216
 217 int write_object_file(const void *buf, unsigned long len,
 218                       const char *type, struct object_id *oid);
 219
 220 int hash_object_file_literally(const void *buf, unsigned long len,
 221                                const char *type, struct object_id *oid,
 222                                unsigned flags);
 223
 224 /*
 225  * Add an object file to the in-memory object store, without writing it
 226  * to disk.
 227  *
 228  * Callers are responsible for calling write_object_file to record the
 229  * object in persistent storage before writing any other new objects
 230  * that reference it.
 231  */
 232 int pretend_object_file(void *, unsigned long, enum object_type,
 233                         struct object_id *oid);
 234
 235 int force_object_loose(const struct object_id *oid, time_t mtime);
 236
 237 /*
 238  * Open the loose object at path, check its hash, and return the contents,
 239  * type, and size. If the object is a blob, then "contents" may return NULL,
 240  * to allow streaming of large blobs.
 241  *
 242  * Returns 0 on success, negative on error (details may be written to stderr).
 243  */
 244 int read_loose_object(const char *path,
 245                       const struct object_id *expected_oid,
 246                       enum object_type *type,
 247                       unsigned long *size,
 248                       void **contents);
 249
 250 /* Retry packed storage after checking packed and loose storage */
 251 #define HAS_OBJECT_RECHECK_PACKED 1
 252
 253 /*
 254  * Returns 1 if the object exists. This function will not lazily fetch objects
 255  * in a partial clone.
 256  */
 257 int has_object(struct repository *r, const struct object_id *oid,
 258                unsigned flags);
 259
 260 /*
 261  * These macros and functions are deprecated. If checking existence for an
 262  * object that is likely to be missing and/or whose absence is relatively
 263  * inconsequential (or is consequential but the caller is prepared to handle
 264  * it), use has_object(), which has better defaults (no lazy fetch in a partial
 265  * clone and no rechecking of packed storage). In the unlikely event that a
 266  * caller needs to assert existence of an object that it fully expects to
 267  * exist, and wants to trigger a lazy fetch in a partial clone, use
 268  * oid_object_info_extended() with a NULL struct object_info.
 269  *
 270  * These functions can be removed once all callers have migrated to
 271  * has_object() and/or oid_object_info_extended().
 272  */
 273 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 274 #define has_sha1_file_with_flags(sha1, flags) repo_has_sha1_file_with_flags(the_repository, sha1, flags)
 275 #define has_sha1_file(sha1) repo_has_sha1_file(the_repository, sha1)
 276 #endif
 277 int repo_has_object_file(struct repository *r, const struct object_id *oid);
 278 int repo_has_object_file_with_flags(struct repository *r,
 279                                     const struct object_id *oid, int flags);
 280 #ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
 281 #define has_object_file(oid) repo_has_object_file(the_repository, oid)
 282 #define has_object_file_with_flags(oid, flags) repo_has_object_file_with_flags(the_repository, oid, flags)
 283 #endif
 284
 285 /*
 286  * Return true iff an alternate object database has a loose object
 287  * with the specified name.  This function does not respect replace
 288  * references.
 289  */
 290 int has_loose_object_nonlocal(const struct object_id *);
 291
 292 void assert_oid_type(const struct object_id *oid, enum object_type expect);
 293
 294 /*
 295  * Enabling the object read lock allows multiple threads to safely call the
 296  * following functions in parallel: repo_read_object_file(), read_object_file(),
 297  * read_object_file_extended(), read_object_with_reference(), read_object(),
 298  * oid_object_info() and oid_object_info_extended().
 299  *
 300  * obj_read_lock() and obj_read_unlock() may also be used to protect other
 301  * section which cannot execute in parallel with object reading. Since the used
 302  * lock is a recursive mutex, these sections can even contain calls to object
 303  * reading functions. However, beware that in these cases zlib inflation won't
 304  * be performed in parallel, losing performance.
 305  *
 306  * TODO: oid_object_info_extended()'s call stack has a recursive behavior. If
 307  * any of its callees end up calling it, this recursive call won't benefit from
 308  * parallel inflation.
 309  */
 310 void enable_obj_read_lock(void);
 311 void disable_obj_read_lock(void);
 312
 313 extern int obj_read_use_lock;
 314 extern pthread_mutex_t obj_read_mutex;
 315
 316 static inline void obj_read_lock(void)
 317 {
 318         if(obj_read_use_lock)
 319                 pthread_mutex_lock(&obj_read_mutex);
 320 }
 321
 322 static inline void obj_read_unlock(void)
 323 {
 324         if(obj_read_use_lock)
 325                 pthread_mutex_unlock(&obj_read_mutex);
 326 }
 327
 328 struct object_info {
 329         /* Request */
 330         enum object_type *typep;
 331         unsigned long *sizep;
 332         off_t *disk_sizep;
 333         struct object_id *delta_base_oid;
 334         struct strbuf *type_name;
 335         void **contentp;
 336
 337         /* Response */
 338         enum {
 339                 OI_CACHED,
 340                 OI_LOOSE,
 341                 OI_PACKED,
 342                 OI_DBCACHED
 343         } whence;
 344         union {
 345                 /*
 346                  * struct {
 347                  *      ... Nothing to expose in this case
 348                  * } cached;
 349                  * struct {
 350                  *      ... Nothing to expose in this case
 351                  * } loose;
 352                  */
 353                 struct {
 354                         struct packed_git *pack;
 355                         off_t offset;
 356                         unsigned int is_delta;
 357                 } packed;
 358         } u;
 359 };
 360
 361 /*
 362  * Initializer for a "struct object_info" that wants no items. You may
 363  * also memset() the memory to all-zeroes.
 364  */
 365 #define OBJECT_INFO_INIT {NULL}
 366
 367 /* Invoke lookup_replace_object() on the given hash */
 368 #define OBJECT_INFO_LOOKUP_REPLACE 1
 369 /* Allow reading from a loose object file of unknown/bogus type */
 370 #define OBJECT_INFO_ALLOW_UNKNOWN_TYPE 2
 371 /* Do not retry packed storage after checking packed and loose storage */
 372 #define OBJECT_INFO_QUICK 8
 373 /* Do not check loose object */
 374 #define OBJECT_INFO_IGNORE_LOOSE 16
 375 /*
 376  * Do not attempt to fetch the object if missing (even if fetch_is_missing is
 377  * nonzero).
 378  */
 379 #define OBJECT_INFO_SKIP_FETCH_OBJECT 32
 380 /*
 381  * This is meant for bulk prefetching of missing blobs in a partial
 382  * clone. Implies OBJECT_INFO_SKIP_FETCH_OBJECT and OBJECT_INFO_QUICK
 383  */
 384 #define OBJECT_INFO_FOR_PREFETCH (OBJECT_INFO_SKIP_FETCH_OBJECT | OBJECT_INFO_QUICK)
 385
 386 int oid_object_info_extended(struct repository *r,
 387                              const struct object_id *,
 388                              struct object_info *, unsigned flags);
 389
 390 /*
 391  * Iterate over the files in the loose-object parts of the object
 392  * directory "path", triggering the following callbacks:
 393  *
 394  *  - loose_object is called for each loose object we find.
 395  *
 396  *  - loose_cruft is called for any files that do not appear to be
 397  *    loose objects. Note that we only look in the loose object
 398  *    directories "objects/[0-9a-f]{2}/", so we will not report
 399  *    "objects/foobar" as cruft.
 400  *
 401  *  - loose_subdir is called for each top-level hashed subdirectory
 402  *    of the object directory (e.g., "$OBJDIR/f0"). It is called
 403  *    after the objects in the directory are processed.
 404  *
 405  * Any callback that is NULL will be ignored. Callbacks returning non-zero
 406  * will end the iteration.
 407  *
 408  * In the "buf" variant, "path" is a strbuf which will also be used as a
 409  * scratch buffer, but restored to its original contents before
 410  * the function returns.
 411  */
 412 typedef int each_loose_object_fn(const struct object_id *oid,
 413                                  const char *path,
 414                                  void *data);
 415 typedef int each_loose_cruft_fn(const char *basename,
 416                                 const char *path,
 417                                 void *data);
 418 typedef int each_loose_subdir_fn(unsigned int nr,
 419                                  const char *path,
 420                                  void *data);
 421 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
 422                                 struct strbuf *path,
 423                                 each_loose_object_fn obj_cb,
 424                                 each_loose_cruft_fn cruft_cb,
 425                                 each_loose_subdir_fn subdir_cb,
 426                                 void *data);
 427 int for_each_loose_file_in_objdir(const char *path,
 428                                   each_loose_object_fn obj_cb,
 429                                   each_loose_cruft_fn cruft_cb,
 430                                   each_loose_subdir_fn subdir_cb,
 431                                   void *data);
 432 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
 433                                       each_loose_object_fn obj_cb,
 434                                       each_loose_cruft_fn cruft_cb,
 435                                       each_loose_subdir_fn subdir_cb,
 436                                       void *data);
 437
 438 /* Flags for for_each_*_object() below. */
 439 enum for_each_object_flags {
 440         /* Iterate only over local objects, not alternates. */
 441         FOR_EACH_OBJECT_LOCAL_ONLY = (1<<0),
 442
 443         /* Only iterate over packs obtained from the promisor remote. */
 444         FOR_EACH_OBJECT_PROMISOR_ONLY = (1<<1),
 445
 446         /*
 447          * Visit objects within a pack in packfile order rather than .idx order
 448          */
 449         FOR_EACH_OBJECT_PACK_ORDER = (1<<2),
 450 };
 451
 452 /*
 453  * Iterate over all accessible loose objects without respect to
 454  * reachability. By default, this includes both local and alternate objects.
 455  * The order in which objects are visited is unspecified.
 456  *
 457  * Any flags specific to packs are ignored.
 458  */
 459 int for_each_loose_object(each_loose_object_fn, void *,
 460                           enum for_each_object_flags flags);
 461
 462 /*
 463  * Iterate over all accessible packed objects without respect to reachability.
 464  * By default, this includes both local and alternate packs.
 465  *
 466  * Note that some objects may appear twice if they are found in multiple packs.
 467  * Each pack is visited in an unspecified order. By default, objects within a
 468  * pack are visited in pack-idx order (i.e., sorted by oid).
 469  */
 470 typedef int each_packed_object_fn(const struct object_id *oid,
 471                                   struct packed_git *pack,
 472                                   uint32_t pos,
 473                                   void *data);
 474 int for_each_object_in_pack(struct packed_git *p,
 475                             each_packed_object_fn, void *data,
 476                             enum for_each_object_flags flags);
 477 int for_each_packed_object(each_packed_object_fn, void *,
 478                            enum for_each_object_flags flags);
 479
 480 #endif /* OBJECT_STORE_H */