6d515a4671e85ad24842dd84d648cef492de9e81
[git/git.git] / 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 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
56 unsigned char *sha1, int *flags);
57
58 char *resolve_refdup(const char *refname, int resolve_flags,
59 unsigned char *sha1, int *flags);
60
61 int read_ref_full(const char *refname, int resolve_flags,
62 unsigned char *sha1, int *flags);
63 int read_ref(const char *refname, unsigned char *sha1);
64
65 int ref_exists(const char *refname);
66
67 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 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 int resolve_gitlink_ref(const char *path, const char *refname,
85 unsigned char *sha1);
86
87 /*
88 * Return true iff abbrev_name is a possible abbreviation for
89 * full_name according to the rules defined by ref_rev_parse_rules in
90 * refs.c.
91 */
92 int refname_match(const char *abbrev_name, const char *full_name);
93
94 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
95 int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
96
97 /*
98 * A ref_transaction represents a collection of ref updates
99 * that should succeed or fail together.
100 *
101 * Calling sequence
102 * ----------------
103 * - Allocate and initialize a `struct ref_transaction` by calling
104 * `ref_transaction_begin()`.
105 *
106 * - List intended ref updates by calling functions like
107 * `ref_transaction_update()` and `ref_transaction_create()`.
108 *
109 * - Call `ref_transaction_commit()` to execute the transaction.
110 * If this succeeds, the ref updates will have taken place and
111 * the transaction cannot be rolled back.
112 *
113 * - Instead of `ref_transaction_commit`, use
114 * `initial_ref_transaction_commit()` if the ref database is known
115 * to be empty (e.g. during clone). This is likely to be much
116 * faster.
117 *
118 * - At any time call `ref_transaction_free()` to discard the
119 * transaction and free associated resources. In particular,
120 * this rolls back the transaction if it has not been
121 * successfully committed.
122 *
123 * Error handling
124 * --------------
125 *
126 * On error, transaction functions append a message about what
127 * went wrong to the 'err' argument. The message mentions what
128 * ref was being updated (if any) when the error occurred so it
129 * can be passed to 'die' or 'error' as-is.
130 *
131 * The message is appended to err without first clearing err.
132 * err will not be '\n' terminated.
133 *
134 * Caveats
135 * -------
136 *
137 * Note that no locks are taken, and no refs are read, until
138 * `ref_transaction_commit` is called. So `ref_transaction_verify`
139 * won't report a verification failure until the commit is attempted.
140 */
141 struct ref_transaction;
142
143 /*
144 * Bit values set in the flags argument passed to each_ref_fn():
145 */
146
147 /* Reference is a symbolic reference. */
148 #define REF_ISSYMREF 0x01
149
150 /* Reference is a packed reference. */
151 #define REF_ISPACKED 0x02
152
153 /*
154 * Reference cannot be resolved to an object name: dangling symbolic
155 * reference (directly or indirectly), corrupt reference file,
156 * reference exists but name is bad, or symbolic reference refers to
157 * ill-formatted reference name.
158 */
159 #define REF_ISBROKEN 0x04
160
161 /*
162 * Reference name is not well formed.
163 *
164 * See git-check-ref-format(1) for the definition of well formed ref names.
165 */
166 #define REF_BAD_NAME 0x08
167
168 /*
169 * The signature for the callback function for the for_each_*()
170 * functions below. The memory pointed to by the refname and sha1
171 * arguments is only guaranteed to be valid for the duration of a
172 * single callback invocation.
173 */
174 typedef int each_ref_fn(const char *refname,
175 const struct object_id *oid, int flags, void *cb_data);
176
177 /*
178 * The following functions invoke the specified callback function for
179 * each reference indicated. If the function ever returns a nonzero
180 * value, stop the iteration and return that value. Please note that
181 * it is not safe to modify references while an iteration is in
182 * progress, unless the same callback function invocation that
183 * modifies the reference also returns a nonzero value to immediately
184 * stop the iteration.
185 */
186 int head_ref(each_ref_fn fn, void *cb_data);
187 int for_each_ref(each_ref_fn fn, void *cb_data);
188 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
189 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data,
190 unsigned int broken);
191 int for_each_tag_ref(each_ref_fn fn, void *cb_data);
192 int for_each_branch_ref(each_ref_fn fn, void *cb_data);
193 int for_each_remote_ref(each_ref_fn fn, void *cb_data);
194 int for_each_replace_ref(each_ref_fn fn, void *cb_data);
195 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data);
196 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
197 const char *prefix, void *cb_data);
198
199 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
200 int for_each_ref_submodule(const char *submodule,
201 each_ref_fn fn, void *cb_data);
202 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
203 each_ref_fn fn, void *cb_data);
204 int for_each_tag_ref_submodule(const char *submodule,
205 each_ref_fn fn, void *cb_data);
206 int for_each_branch_ref_submodule(const char *submodule,
207 each_ref_fn fn, void *cb_data);
208 int for_each_remote_ref_submodule(const char *submodule,
209 each_ref_fn fn, void *cb_data);
210
211 int head_ref_namespaced(each_ref_fn fn, void *cb_data);
212 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);
213
214 /* can be used to learn about broken ref and symref */
215 int for_each_rawref(each_ref_fn fn, void *cb_data);
216
217 static inline const char *has_glob_specials(const char *pattern)
218 {
219 return strpbrk(pattern, "?*[");
220 }
221
222 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname);
223 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt,
224 const struct string_list *refnames);
225
226 /*
227 * Flags for controlling behaviour of pack_refs()
228 * PACK_REFS_PRUNE: Prune loose refs after packing
229 * PACK_REFS_ALL: Pack _all_ refs, not just tags and already packed refs
230 */
231 #define PACK_REFS_PRUNE 0x0001
232 #define PACK_REFS_ALL 0x0002
233
234 /*
235 * Write a packed-refs file for the current repository.
236 * flags: Combination of the above PACK_REFS_* flags.
237 */
238 int pack_refs(unsigned int flags);
239
240 /*
241 * Flags controlling ref_transaction_update(), ref_transaction_create(), etc.
242 * REF_NODEREF: act on the ref directly, instead of dereferencing
243 * symbolic references.
244 *
245 * Other flags are reserved for internal use.
246 */
247 #define REF_NODEREF 0x01
248 #define REF_FORCE_CREATE_REFLOG 0x40
249
250 /*
251 * Setup reflog before using. Fill in err and return -1 on failure.
252 */
253 int safe_create_reflog(const char *refname, int force_create, struct strbuf *err);
254
255 /** Reads log for the value of ref during at_time. **/
256 int read_ref_at(const char *refname, unsigned int flags,
257 unsigned long at_time, int cnt,
258 unsigned char *sha1, char **msg,
259 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);
260
261 /** Check if a particular reflog exists */
262 int reflog_exists(const char *refname);
263
264 /*
265 * Delete the specified reference. If old_sha1 is non-NULL, then
266 * verify that the current value of the reference is old_sha1 before
267 * deleting it. If old_sha1 is NULL, delete the reference if it
268 * exists, regardless of its old value. It is an error for old_sha1 to
269 * be NULL_SHA1. flags is passed through to ref_transaction_delete().
270 */
271 int delete_ref(const char *refname, const unsigned char *old_sha1,
272 unsigned int flags);
273
274 /*
275 * Delete the specified references. If there are any problems, emit
276 * errors but attempt to keep going (i.e., the deletes are not done in
277 * an all-or-nothing transaction). flags is passed through to
278 * ref_transaction_delete().
279 */
280 int delete_refs(struct string_list *refnames, unsigned int flags);
281
282 /** Delete a reflog */
283 int delete_reflog(const char *refname);
284
285 /* iterate over reflog entries */
286 typedef int each_reflog_ent_fn(
287 unsigned char *old_sha1, unsigned char *new_sha1,
288 const char *committer, unsigned long timestamp,
289 int tz, const char *msg, void *cb_data);
290
291 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
292 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
293
294 /*
295 * Calls the specified function for each reflog file until it returns nonzero,
296 * and returns the value
297 */
298 int for_each_reflog(each_ref_fn fn, void *cb_data);
299
300 #define REFNAME_ALLOW_ONELEVEL 1
301 #define REFNAME_REFSPEC_PATTERN 2
302
303 /*
304 * Return 0 iff refname has the correct format for a refname according
305 * to the rules described in Documentation/git-check-ref-format.txt.
306 * If REFNAME_ALLOW_ONELEVEL is set in flags, then accept one-level
307 * reference names. If REFNAME_REFSPEC_PATTERN is set in flags, then
308 * allow a single "*" wildcard character in the refspec. No leading or
309 * repeated slashes are accepted.
310 */
311 int check_refname_format(const char *refname, int flags);
312
313 const char *prettify_refname(const char *refname);
314
315 char *shorten_unambiguous_ref(const char *refname, int strict);
316
317 /** rename ref, return 0 on success **/
318 int rename_ref(const char *oldref, const char *newref, const char *logmsg);
319
320 int create_symref(const char *refname, const char *target, const char *logmsg);
321
322 /*
323 * Update HEAD of the specified gitdir.
324 * Similar to create_symref("relative-git-dir/HEAD", target, NULL), but
325 * this can update the main working tree's HEAD regardless of where
326 * $GIT_DIR points to.
327 * Return 0 if successful, non-zero otherwise.
328 * */
329 int set_worktree_head_symref(const char *gitdir, const char *target);
330
331 enum action_on_err {
332 UPDATE_REFS_MSG_ON_ERR,
333 UPDATE_REFS_DIE_ON_ERR,
334 UPDATE_REFS_QUIET_ON_ERR
335 };
336
337 /*
338 * Begin a reference transaction. The reference transaction must
339 * be freed by calling ref_transaction_free().
340 */
341 struct ref_transaction *ref_transaction_begin(struct strbuf *err);
342
343 /*
344 * Reference transaction updates
345 *
346 * The following four functions add a reference check or update to a
347 * ref_transaction. They have some common similar parameters:
348 *
349 * transaction -- a pointer to an open ref_transaction, obtained
350 * from ref_transaction_begin().
351 *
352 * refname -- the name of the reference to be affected.
353 *
354 * flags -- flags affecting the update, passed to
355 * update_ref_lock(). Can be REF_NODEREF, which means that
356 * symbolic references should not be followed.
357 *
358 * msg -- a message describing the change (for the reflog).
359 *
360 * err -- a strbuf for receiving a description of any error that
361 * might have occured.
362 *
363 * The functions make internal copies of refname and msg, so the
364 * caller retains ownership of these parameters.
365 *
366 * The functions return 0 on success and non-zero on failure. A
367 * failure means that the transaction as a whole has failed and needs
368 * to be rolled back.
369 */
370
371 /*
372 * Add a reference update to transaction. new_sha1 is the value that
373 * the reference should have after the update, or null_sha1 if it
374 * should be deleted. If new_sha1 is NULL, then the reference is not
375 * changed at all. old_sha1 is the value that the reference must have
376 * before the update, or null_sha1 if it must not have existed
377 * beforehand. The old value is checked after the lock is taken to
378 * prevent races. If the old value doesn't agree with old_sha1, the
379 * whole transaction fails. If old_sha1 is NULL, then the previous
380 * value is not checked.
381 *
382 * See the above comment "Reference transaction updates" for more
383 * information.
384 */
385 int ref_transaction_update(struct ref_transaction *transaction,
386 const char *refname,
387 const unsigned char *new_sha1,
388 const unsigned char *old_sha1,
389 unsigned int flags, const char *msg,
390 struct strbuf *err);
391
392 /*
393 * Add a reference creation to transaction. new_sha1 is the value that
394 * the reference should have after the update; it must not be
395 * null_sha1. It is verified that the reference does not exist
396 * already.
397 *
398 * See the above comment "Reference transaction updates" for more
399 * information.
400 */
401 int ref_transaction_create(struct ref_transaction *transaction,
402 const char *refname,
403 const unsigned char *new_sha1,
404 unsigned int flags, const char *msg,
405 struct strbuf *err);
406
407 /*
408 * Add a reference deletion to transaction. If old_sha1 is non-NULL,
409 * then it holds the value that the reference should have had before
410 * the update (which must not be null_sha1).
411 *
412 * See the above comment "Reference transaction updates" for more
413 * information.
414 */
415 int ref_transaction_delete(struct ref_transaction *transaction,
416 const char *refname,
417 const unsigned char *old_sha1,
418 unsigned int flags, const char *msg,
419 struct strbuf *err);
420
421 /*
422 * Verify, within a transaction, that refname has the value old_sha1,
423 * or, if old_sha1 is null_sha1, then verify that the reference
424 * doesn't exist. old_sha1 must be non-NULL.
425 *
426 * See the above comment "Reference transaction updates" for more
427 * information.
428 */
429 int ref_transaction_verify(struct ref_transaction *transaction,
430 const char *refname,
431 const unsigned char *old_sha1,
432 unsigned int flags,
433 struct strbuf *err);
434
435 /*
436 * Commit all of the changes that have been queued in transaction, as
437 * atomically as possible.
438 *
439 * Returns 0 for success, or one of the below error codes for errors.
440 */
441 /* Naming conflict (for example, the ref names A and A/B conflict). */
442 #define TRANSACTION_NAME_CONFLICT -1
443 /* All other errors. */
444 #define TRANSACTION_GENERIC_ERROR -2
445 int ref_transaction_commit(struct ref_transaction *transaction,
446 struct strbuf *err);
447
448 /*
449 * Like ref_transaction_commit(), but optimized for creating
450 * references when originally initializing a repository (e.g., by "git
451 * clone"). It writes the new references directly to packed-refs
452 * without locking the individual references.
453 *
454 * It is a bug to call this function when there might be other
455 * processes accessing the repository or if there are existing
456 * references that might conflict with the ones being created. All
457 * old_sha1 values must either be absent or NULL_SHA1.
458 */
459 int initial_ref_transaction_commit(struct ref_transaction *transaction,
460 struct strbuf *err);
461
462 /*
463 * Free an existing transaction and all associated data.
464 */
465 void ref_transaction_free(struct ref_transaction *transaction);
466
467 /**
468 * Lock, update, and unlock a single reference. This function
469 * basically does a transaction containing a single call to
470 * ref_transaction_update(). The parameters to this function have the
471 * same meaning as the corresponding parameters to
472 * ref_transaction_update(). Handle errors as requested by the `onerr`
473 * argument.
474 */
475 int update_ref(const char *msg, const char *refname,
476 const unsigned char *new_sha1, const unsigned char *old_sha1,
477 unsigned int flags, enum action_on_err onerr);
478
479 int parse_hide_refs_config(const char *var, const char *value, const char *);
480
481 /*
482 * Check whether a ref is hidden. If no namespace is set, both the first and
483 * the second parameter point to the full ref name. If a namespace is set and
484 * the ref is inside that namespace, the first parameter is a pointer to the
485 * name of the ref with the namespace prefix removed. If a namespace is set and
486 * the ref is outside that namespace, the first parameter is NULL. The second
487 * parameter always points to the full ref name.
488 */
489 int ref_is_hidden(const char *, const char *);
490
491 enum ref_type {
492 REF_TYPE_PER_WORKTREE,
493 REF_TYPE_PSEUDOREF,
494 REF_TYPE_NORMAL,
495 };
496
497 enum ref_type ref_type(const char *refname);
498
499 enum expire_reflog_flags {
500 EXPIRE_REFLOGS_DRY_RUN = 1 << 0,
501 EXPIRE_REFLOGS_UPDATE_REF = 1 << 1,
502 EXPIRE_REFLOGS_VERBOSE = 1 << 2,
503 EXPIRE_REFLOGS_REWRITE = 1 << 3
504 };
505
506 /*
507 * The following interface is used for reflog expiration. The caller
508 * calls reflog_expire(), supplying it with three callback functions,
509 * of the following types. The callback functions define the
510 * expiration policy that is desired.
511 *
512 * reflog_expiry_prepare_fn -- Called once after the reference is
513 * locked.
514 *
515 * reflog_expiry_should_prune_fn -- Called once for each entry in the
516 * existing reflog. It should return true iff that entry should be
517 * pruned.
518 *
519 * reflog_expiry_cleanup_fn -- Called once before the reference is
520 * unlocked again.
521 */
522 typedef void reflog_expiry_prepare_fn(const char *refname,
523 const unsigned char *sha1,
524 void *cb_data);
525 typedef int reflog_expiry_should_prune_fn(unsigned char *osha1,
526 unsigned char *nsha1,
527 const char *email,
528 unsigned long timestamp, int tz,
529 const char *message, void *cb_data);
530 typedef void reflog_expiry_cleanup_fn(void *cb_data);
531
532 /*
533 * Expire reflog entries for the specified reference. sha1 is the old
534 * value of the reference. flags is a combination of the constants in
535 * enum expire_reflog_flags. The three function pointers are described
536 * above. On success, return zero.
537 */
538 int reflog_expire(const char *refname, const unsigned char *sha1,
539 unsigned int flags,
540 reflog_expiry_prepare_fn prepare_fn,
541 reflog_expiry_should_prune_fn should_prune_fn,
542 reflog_expiry_cleanup_fn cleanup_fn,
543 void *policy_cb_data);
544
545 #endif /* REFS_H */