refs.h

   1 #ifndef REFS_H
   2 #define REFS_H
   3
   4 /*
   5  * Resolve a reference, recursively following symbolic refererences.
   6  *
   7  * Store the referred-to object's name in sha1 and return the name of
   8  * the non-symbolic reference that ultimately pointed at it.  The
   9  * return value, if not NULL, is a pointer into either a static buffer
  10  * or the input ref.
  11  *
  12  * If the reference cannot be resolved to an object, the behavior
  13  * depends on the RESOLVE_REF_READING flag:
  14  *
  15  * - If RESOLVE_REF_READING is set, return NULL.
  16  *
  17  * - If RESOLVE_REF_READING is not set, clear sha1 and return the name of
  18  *   the last reference name in the chain, which will either be a non-symbolic
  19  *   reference or an undefined reference.  If this is a prelude to
  20  *   "writing" to the ref, the return value is the name of the ref
  21  *   that will actually be created or changed.
  22  *
  23  * If the RESOLVE_REF_NO_RECURSE flag is passed, only resolves one
  24  * level of symbolic reference.  The value stored in sha1 for a symbolic
  25  * reference will always be null_sha1 in this case, and the return
  26  * value is the reference that the symref refers to directly.
  27  *
  28  * If flags is non-NULL, set the value that it points to the
  29  * combination of REF_ISPACKED (if the reference was found among the
  30  * packed references), REF_ISSYMREF (if the initial reference was a
  31  * symbolic reference), REF_BAD_NAME (if the reference name is ill
  32  * formed --- see RESOLVE_REF_ALLOW_BAD_NAME below), and REF_ISBROKEN
  33  * (if the ref is malformed or has a bad name). See refs.h for more detail
  34  * on each flag.
  35  *
  36  * If ref is not a properly-formatted, normalized reference, return
  37  * NULL.  If more than MAXDEPTH recursive symbolic lookups are needed,
  38  * give up and return NULL.
  39  *
  40  * RESOLVE_REF_ALLOW_BAD_NAME allows resolving refs even when their
  41  * name is invalid according to git-check-ref-format(1).  If the name
  42  * is bad then the value stored in sha1 will be null_sha1 and the two
  43  * flags REF_ISBROKEN and REF_BAD_NAME will be set.
  44  *
  45  * Even with RESOLVE_REF_ALLOW_BAD_NAME, names that escape the refs/
  46  * directory and do not consist of all caps and underscores cannot be
  47  * resolved. The function returns NULL for such ref names.
  48  * Caps and underscores refers to the special refs, such as HEAD,
  49  * FETCH_HEAD and friends, that all live outside of the refs/ directory.
  50  */
  51 #define RESOLVE_REF_READING 0x01
  52 #define RESOLVE_REF_NO_RECURSE 0x02
  53 #define RESOLVE_REF_ALLOW_BAD_NAME 0x04
  54
  55 extern const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
  56                                       unsigned char *sha1, int *flags);
  57
  58 extern char *resolve_refdup(const char *refname, int resolve_flags,
  59                             unsigned char *sha1, int *flags);
  60
  61 extern int read_ref_full(const char *refname, int resolve_flags,
  62                          unsigned char *sha1, int *flags);
  63 extern int read_ref(const char *refname, unsigned char *sha1);
  64
  65 extern int ref_exists(const char *refname);
  66
  67 extern int is_branch(const char *refname);
  68
  69 /*
  70  * If refname is a non-symbolic reference that refers to a tag object,
  71  * and the tag can be (recursively) dereferenced to a non-tag object,
  72  * store the SHA1 of the referred-to object to sha1 and return 0.  If
  73  * any of these conditions are not met, return a non-zero value.
  74  * Symbolic references are considered unpeelable, even if they
  75  * ultimately resolve to a peelable tag.
  76  */
  77 extern int peel_ref(const char *refname, unsigned char *sha1);
  78
  79 /**
  80  * Resolve refname in the nested "gitlink" repository that is located
  81  * at path.  If the resolution is successful, return 0 and set sha1 to
  82  * the name of the object; otherwise, return a non-zero value.
  83  */
  84 extern int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1);
  85
  86 /*
  87  * Return true iff abbrev_name is a possible abbreviation for
  88  * full_name according to the rules defined by ref_rev_parse_rules in
  89  * refs.c.
  90  */
  91 extern int refname_match(const char *abbrev_name, const char *full_name);
  92
  93 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
  94 extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
  95
  96 /*
  97  * A ref_transaction represents a collection of ref updates
  98  * that should succeed or fail together.
  99  *
 100  * Calling sequence
 101  * ----------------
 102  * - Allocate and initialize a `struct ref_transaction` by calling
 103  *   `ref_transaction_begin()`.
 104  *
 105  * - List intended ref updates by calling functions like
 106  *   `ref_transaction_update()` and `ref_transaction_create()`.
 107  *
 108  * - Call `ref_transaction_commit()` to execute the transaction.
 109  *   If this succeeds, the ref updates will have taken place and
 110  *   the transaction cannot be rolled back.
 111  *
 112  * - At any time call `ref_transaction_free()` to discard the
 113  *   transaction and free associated resources.  In particular,
 114  *   this rolls back the transaction if it has not been
 115  *   successfully committed.
 116  *
 117  * Error handling
 118  * --------------
 119  *
 120  * On error, transaction functions append a message about what
 121  * went wrong to the 'err' argument.  The message mentions what
 122  * ref was being updated (if any) when the error occurred so it
 123  * can be passed to 'die' or 'error' as-is.
 124  *
 125  * The message is appended to err without first clearing err.
 126  * err will not be '\n' terminated.
 127  */
 128 struct ref_transaction;
 129
 130 /*
 131  * Bit values set in the flags argument passed to each_ref_fn():
 132  */
 133
 134 /* Reference is a symbolic reference. */
 135 #define REF_ISSYMREF 0x01
 136
 137 /* Reference is a packed reference. */
 138 #define REF_ISPACKED 0x02
 139
 140 /*
 141  * Reference cannot be resolved to an object name: dangling symbolic
 142  * reference (directly or indirectly), corrupt reference file,
 143  * reference exists but name is bad, or symbolic reference refers to
 144  * ill-formatted reference name.
 145  */
 146 #define REF_ISBROKEN 0x04
 147
 148 /*
 149  * Reference name is not well formed.
 150  *
 151  * See git-check-ref-format(1) for the definition of well formed ref names.
 152  */
 153 #define REF_BAD_NAME 0x08
 154
 155 /*
 156  * The signature for the callback function for the for_each_*()
 157  * functions below.  The memory pointed to by the refname and sha1
 158  * arguments is only guaranteed to be valid for the duration of a
 159  * single callback invocation.
 160  */
 161 typedef int each_ref_fn(const char *refname,
 162                         const struct object_id *oid, int flags, void *cb_data);
 163
 164 /*
 165  * The following functions invoke the specified callback function for
 166  * each reference indicated.  If the function ever returns a nonzero
 167  * value, stop the iteration and return that value.  Please note that
 168  * it is not safe to modify references while an iteration is in
 169  * progress, unless the same callback function invocation that
 170  * modifies the reference also returns a nonzero value to immediately
 171  * stop the iteration.
 172  */
 173 extern int head_ref(each_ref_fn fn, void *cb_data);
 174 extern int for_each_ref(each_ref_fn fn, void *cb_data);
 175 extern int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
 176 extern int for_each_tag_ref(each_ref_fn fn, void *cb_data);
 177 extern int for_each_branch_ref(each_ref_fn fn, void *cb_data);
 178 extern int for_each_remote_ref(each_ref_fn fn, void *cb_data);
 179 extern int for_each_replace_ref(each_ref_fn fn, void *cb_data);
 180 extern int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data);
 181 extern int for_each_glob_ref_in(each_ref_fn fn, const char *pattern, const char *prefix, void *cb_data);
 182
 183 extern int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
 184 extern int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
 185 extern int for_each_ref_in_submodule(const char *submodule, const char *prefix,
 186                 each_ref_fn fn, void *cb_data);
 187 extern int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
 188 extern int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
 189 extern int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
 190
 191 extern int head_ref_namespaced(each_ref_fn fn, void *cb_data);
 192 extern int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);
 193
 194 /* can be used to learn about broken ref and symref */
 195 extern int for_each_rawref(each_ref_fn fn, void *cb_data);
 196
 197 static inline const char *has_glob_specials(const char *pattern)
 198 {
 199         return strpbrk(pattern, "?*[");
 200 }
 201
 202 extern void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname);
 203 extern void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames);
 204
 205 /*
 206  * Flags for controlling behaviour of pack_refs()
 207  * PACK_REFS_PRUNE: Prune loose refs after packing
 208  * PACK_REFS_ALL:   Pack _all_ refs, not just tags and already packed refs
 209  */
 210 #define PACK_REFS_PRUNE 0x0001
 211 #define PACK_REFS_ALL   0x0002
 212
 213 /*
 214  * Write a packed-refs file for the current repository.
 215  * flags: Combination of the above PACK_REFS_* flags.
 216  */
 217 int pack_refs(unsigned int flags);
 218
 219 /*
 220  * Flags controlling ref_transaction_update(), ref_transaction_create(), etc.
 221  * REF_NODEREF: act on the ref directly, instead of dereferencing
 222  *              symbolic references.
 223  *
 224  * Other flags are reserved for internal use.
 225  */
 226 #define REF_NODEREF     0x01
 227
 228 /*
 229  * Setup reflog before using. Set errno to something meaningful on failure.
 230  */
 231 int log_ref_setup(const char *refname, struct strbuf *logfile);
 232
 233 /** Reads log for the value of ref during at_time. **/
 234 extern int read_ref_at(const char *refname, unsigned int flags,
 235                        unsigned long at_time, int cnt,
 236                        unsigned char *sha1, char **msg,
 237                        unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);
 238
 239 /** Check if a particular reflog exists */
 240 extern int reflog_exists(const char *refname);
 241
 242 /*
 243  * Delete the specified reference. If old_sha1 is non-NULL, then
 244  * verify that the current value of the reference is old_sha1 before
 245  * deleting it. If old_sha1 is NULL, delete the reference if it
 246  * exists, regardless of its old value. It is an error for old_sha1 to
 247  * be NULL_SHA1. flags is passed through to ref_transaction_delete().
 248  */
 249 extern int delete_ref(const char *refname, const unsigned char *old_sha1,
 250                       unsigned int flags);
 251
 252 /*
 253  * Delete the specified references. If there are any problems, emit
 254  * errors but attempt to keep going (i.e., the deletes are not done in
 255  * an all-or-nothing transaction).
 256  */
 257 extern int delete_refs(struct string_list *refnames);
 258
 259 /** Delete a reflog */
 260 extern int delete_reflog(const char *refname);
 261
 262 /* iterate over reflog entries */
 263 typedef int each_reflog_ent_fn(unsigned char *osha1, unsigned char *nsha1, const char *, unsigned long, int, const char *, void *);
 264 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
 265 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
 266
 267 /*
 268  * Calls the specified function for each reflog file until it returns nonzero,
 269  * and returns the value
 270  */
 271 extern int for_each_reflog(each_ref_fn, void *);
 272
 273 #define REFNAME_ALLOW_ONELEVEL 1
 274 #define REFNAME_REFSPEC_PATTERN 2
 275
 276 /*
 277  * Return 0 iff refname has the correct format for a refname according
 278  * to the rules described in Documentation/git-check-ref-format.txt.
 279  * If REFNAME_ALLOW_ONELEVEL is set in flags, then accept one-level
 280  * reference names.  If REFNAME_REFSPEC_PATTERN is set in flags, then
 281  * allow a "*" wildcard character in place of one of the name
 282  * components.  No leading or repeated slashes are accepted.
 283  */
 284 extern int check_refname_format(const char *refname, int flags);
 285
 286 extern const char *prettify_refname(const char *refname);
 287
 288 extern char *shorten_unambiguous_ref(const char *refname, int strict);
 289
 290 /** rename ref, return 0 on success **/
 291 extern int rename_ref(const char *oldref, const char *newref, const char *logmsg);
 292
 293 extern int create_symref(const char *ref, const char *refs_heads_master, const char *logmsg);
 294
 295 enum action_on_err {
 296         UPDATE_REFS_MSG_ON_ERR,
 297         UPDATE_REFS_DIE_ON_ERR,
 298         UPDATE_REFS_QUIET_ON_ERR
 299 };
 300
 301 /*
 302  * Begin a reference transaction.  The reference transaction must
 303  * be freed by calling ref_transaction_free().
 304  */
 305 struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 306
 307 /*
 308  * Reference transaction updates
 309  *
 310  * The following four functions add a reference check or update to a
 311  * ref_transaction.  They have some common similar parameters:
 312  *
 313  *     transaction -- a pointer to an open ref_transaction, obtained
 314  *         from ref_transaction_begin().
 315  *
 316  *     refname -- the name of the reference to be affected.
 317  *
 318  *     flags -- flags affecting the update, passed to
 319  *         update_ref_lock(). Can be REF_NODEREF, which means that
 320  *         symbolic references should not be followed.
 321  *
 322  *     msg -- a message describing the change (for the reflog).
 323  *
 324  *     err -- a strbuf for receiving a description of any error that
 325  *         might have occured.
 326  *
 327  * The functions make internal copies of refname and msg, so the
 328  * caller retains ownership of these parameters.
 329  *
 330  * The functions return 0 on success and non-zero on failure. A
 331  * failure means that the transaction as a whole has failed and needs
 332  * to be rolled back.
 333  */
 334
 335 /*
 336  * Add a reference update to transaction. new_sha1 is the value that
 337  * the reference should have after the update, or null_sha1 if it
 338  * should be deleted. If new_sha1 is NULL, then the reference is not
 339  * changed at all. old_sha1 is the value that the reference must have
 340  * before the update, or null_sha1 if it must not have existed
 341  * beforehand. The old value is checked after the lock is taken to
 342  * prevent races. If the old value doesn't agree with old_sha1, the
 343  * whole transaction fails. If old_sha1 is NULL, then the previous
 344  * value is not checked.
 345  *
 346  * See the above comment "Reference transaction updates" for more
 347  * information.
 348  */
 349 int ref_transaction_update(struct ref_transaction *transaction,
 350                            const char *refname,
 351                            const unsigned char *new_sha1,
 352                            const unsigned char *old_sha1,
 353                            unsigned int flags, const char *msg,
 354                            struct strbuf *err);
 355
 356 /*
 357  * Add a reference creation to transaction. new_sha1 is the value that
 358  * the reference should have after the update; it must not be
 359  * null_sha1. It is verified that the reference does not exist
 360  * already.
 361  *
 362  * See the above comment "Reference transaction updates" for more
 363  * information.
 364  */
 365 int ref_transaction_create(struct ref_transaction *transaction,
 366                            const char *refname,
 367                            const unsigned char *new_sha1,
 368                            unsigned int flags, const char *msg,
 369                            struct strbuf *err);
 370
 371 /*
 372  * Add a reference deletion to transaction. If old_sha1 is non-NULL,
 373  * then it holds the value that the reference should have had before
 374  * the update (which must not be null_sha1).
 375  *
 376  * See the above comment "Reference transaction updates" for more
 377  * information.
 378  */
 379 int ref_transaction_delete(struct ref_transaction *transaction,
 380                            const char *refname,
 381                            const unsigned char *old_sha1,
 382                            unsigned int flags, const char *msg,
 383                            struct strbuf *err);
 384
 385 /*
 386  * Verify, within a transaction, that refname has the value old_sha1,
 387  * or, if old_sha1 is null_sha1, then verify that the reference
 388  * doesn't exist. old_sha1 must be non-NULL.
 389  *
 390  * See the above comment "Reference transaction updates" for more
 391  * information.
 392  */
 393 int ref_transaction_verify(struct ref_transaction *transaction,
 394                            const char *refname,
 395                            const unsigned char *old_sha1,
 396                            unsigned int flags,
 397                            struct strbuf *err);
 398
 399 /*
 400  * Commit all of the changes that have been queued in transaction, as
 401  * atomically as possible.
 402  *
 403  * Returns 0 for success, or one of the below error codes for errors.
 404  */
 405 /* Naming conflict (for example, the ref names A and A/B conflict). */
 406 #define TRANSACTION_NAME_CONFLICT -1
 407 /* All other errors. */
 408 #define TRANSACTION_GENERIC_ERROR -2
 409 int ref_transaction_commit(struct ref_transaction *transaction,
 410                            struct strbuf *err);
 411
 412 /*
 413  * Like ref_transaction_commit(), but optimized for creating
 414  * references when originally initializing a repository (e.g., by "git
 415  * clone"). It writes the new references directly to packed-refs
 416  * without locking the individual references.
 417  *
 418  * It is a bug to call this function when there might be other
 419  * processes accessing the repository or if there are existing
 420  * references that might conflict with the ones being created. All
 421  * old_sha1 values must either be absent or NULL_SHA1.
 422  */
 423 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 424                                    struct strbuf *err);
 425
 426 /*
 427  * Free an existing transaction and all associated data.
 428  */
 429 void ref_transaction_free(struct ref_transaction *transaction);
 430
 431 /**
 432  * Lock, update, and unlock a single reference. This function
 433  * basically does a transaction containing a single call to
 434  * ref_transaction_update(). The parameters to this function have the
 435  * same meaning as the corresponding parameters to
 436  * ref_transaction_update(). Handle errors as requested by the `onerr`
 437  * argument.
 438  */
 439 int update_ref(const char *msg, const char *refname,
 440                const unsigned char *new_sha1, const unsigned char *old_sha1,
 441                unsigned int flags, enum action_on_err onerr);
 442
 443 extern int parse_hide_refs_config(const char *var, const char *value, const char *);
 444
 445 extern int ref_is_hidden(const char *);
 446
 447 enum expire_reflog_flags {
 448         EXPIRE_REFLOGS_DRY_RUN = 1 << 0,
 449         EXPIRE_REFLOGS_UPDATE_REF = 1 << 1,
 450         EXPIRE_REFLOGS_VERBOSE = 1 << 2,
 451         EXPIRE_REFLOGS_REWRITE = 1 << 3
 452 };
 453
 454 /*
 455  * The following interface is used for reflog expiration. The caller
 456  * calls reflog_expire(), supplying it with three callback functions,
 457  * of the following types. The callback functions define the
 458  * expiration policy that is desired.
 459  *
 460  * reflog_expiry_prepare_fn -- Called once after the reference is
 461  *     locked.
 462  *
 463  * reflog_expiry_should_prune_fn -- Called once for each entry in the
 464  *     existing reflog. It should return true iff that entry should be
 465  *     pruned.
 466  *
 467  * reflog_expiry_cleanup_fn -- Called once before the reference is
 468  *     unlocked again.
 469  */
 470 typedef void reflog_expiry_prepare_fn(const char *refname,
 471                                       const unsigned char *sha1,
 472                                       void *cb_data);
 473 typedef int reflog_expiry_should_prune_fn(unsigned char *osha1,
 474                                           unsigned char *nsha1,
 475                                           const char *email,
 476                                           unsigned long timestamp, int tz,
 477                                           const char *message, void *cb_data);
 478 typedef void reflog_expiry_cleanup_fn(void *cb_data);
 479
 480 /*
 481  * Expire reflog entries for the specified reference. sha1 is the old
 482  * value of the reference. flags is a combination of the constants in
 483  * enum expire_reflog_flags. The three function pointers are described
 484  * above. On success, return zero.
 485  */
 486 extern int reflog_expire(const char *refname, const unsigned char *sha1,
 487                          unsigned int flags,
 488                          reflog_expiry_prepare_fn prepare_fn,
 489                          reflog_expiry_should_prune_fn should_prune_fn,
 490                          reflog_expiry_cleanup_fn cleanup_fn,
 491                          void *policy_cb_data);
 492
 493 #endif /* REFS_H */