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