refs: introduce an iterator interface
[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() and
145 * stored in ref_iterator::flags. Other bits are for internal use
146 * only:
147 */
148
149 /* Reference is a symbolic reference. */
150 #define REF_ISSYMREF 0x01
151
152 /* Reference is a packed reference. */
153 #define REF_ISPACKED 0x02
154
155 /*
156 * Reference cannot be resolved to an object name: dangling symbolic
157 * reference (directly or indirectly), corrupt reference file,
158 * reference exists but name is bad, or symbolic reference refers to
159 * ill-formatted reference name.
160 */
161 #define REF_ISBROKEN 0x04
162
163 /*
164 * Reference name is not well formed.
165 *
166 * See git-check-ref-format(1) for the definition of well formed ref names.
167 */
168 #define REF_BAD_NAME 0x08
169
170 /*
171 * The signature for the callback function for the for_each_*()
172 * functions below. The memory pointed to by the refname and sha1
173 * arguments is only guaranteed to be valid for the duration of a
174 * single callback invocation.
175 */
176 typedef int each_ref_fn(const char *refname,
177 const struct object_id *oid, int flags, void *cb_data);
178
179 /*
180 * The following functions invoke the specified callback function for
181 * each reference indicated. If the function ever returns a nonzero
182 * value, stop the iteration and return that value. Please note that
183 * it is not safe to modify references while an iteration is in
184 * progress, unless the same callback function invocation that
185 * modifies the reference also returns a nonzero value to immediately
186 * stop the iteration.
187 */
188 int head_ref(each_ref_fn fn, void *cb_data);
189 int for_each_ref(each_ref_fn fn, void *cb_data);
190 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
191 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data,
192 unsigned int broken);
193 int for_each_tag_ref(each_ref_fn fn, void *cb_data);
194 int for_each_branch_ref(each_ref_fn fn, void *cb_data);
195 int for_each_remote_ref(each_ref_fn fn, void *cb_data);
196 int for_each_replace_ref(each_ref_fn fn, void *cb_data);
197 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data);
198 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
199 const char *prefix, void *cb_data);
200
201 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
202 int for_each_ref_submodule(const char *submodule,
203 each_ref_fn fn, void *cb_data);
204 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
205 each_ref_fn fn, void *cb_data);
206 int for_each_tag_ref_submodule(const char *submodule,
207 each_ref_fn fn, void *cb_data);
208 int for_each_branch_ref_submodule(const char *submodule,
209 each_ref_fn fn, void *cb_data);
210 int for_each_remote_ref_submodule(const char *submodule,
211 each_ref_fn fn, void *cb_data);
212
213 int head_ref_namespaced(each_ref_fn fn, void *cb_data);
214 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);
215
216 /* can be used to learn about broken ref and symref */
217 int for_each_rawref(each_ref_fn fn, void *cb_data);
218
219 static inline const char *has_glob_specials(const char *pattern)
220 {
221 return strpbrk(pattern, "?*[");
222 }
223
224 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname);
225 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt,
226 const struct string_list *refnames);
227
228 /*
229 * Flags for controlling behaviour of pack_refs()
230 * PACK_REFS_PRUNE: Prune loose refs after packing
231 * PACK_REFS_ALL: Pack _all_ refs, not just tags and already packed refs
232 */
233 #define PACK_REFS_PRUNE 0x0001
234 #define PACK_REFS_ALL 0x0002
235
236 /*
237 * Write a packed-refs file for the current repository.
238 * flags: Combination of the above PACK_REFS_* flags.
239 */
240 int pack_refs(unsigned int flags);
241
242 /*
243 * Flags controlling ref_transaction_update(), ref_transaction_create(), etc.
244 * REF_NODEREF: act on the ref directly, instead of dereferencing
245 * symbolic references.
246 *
247 * Other flags are reserved for internal use.
248 */
249 #define REF_NODEREF 0x01
250 #define REF_FORCE_CREATE_REFLOG 0x40
251
252 /*
253 * Setup reflog before using. Fill in err and return -1 on failure.
254 */
255 int safe_create_reflog(const char *refname, int force_create, struct strbuf *err);
256
257 /** Reads log for the value of ref during at_time. **/
258 int read_ref_at(const char *refname, unsigned int flags,
259 unsigned long at_time, int cnt,
260 unsigned char *sha1, char **msg,
261 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);
262
263 /** Check if a particular reflog exists */
264 int reflog_exists(const char *refname);
265
266 /*
267 * Delete the specified reference. If old_sha1 is non-NULL, then
268 * verify that the current value of the reference is old_sha1 before
269 * deleting it. If old_sha1 is NULL, delete the reference if it
270 * exists, regardless of its old value. It is an error for old_sha1 to
271 * be NULL_SHA1. flags is passed through to ref_transaction_delete().
272 */
273 int delete_ref(const char *refname, const unsigned char *old_sha1,
274 unsigned int flags);
275
276 /*
277 * Delete the specified references. If there are any problems, emit
278 * errors but attempt to keep going (i.e., the deletes are not done in
279 * an all-or-nothing transaction). flags is passed through to
280 * ref_transaction_delete().
281 */
282 int delete_refs(struct string_list *refnames, unsigned int flags);
283
284 /** Delete a reflog */
285 int delete_reflog(const char *refname);
286
287 /* iterate over reflog entries */
288 typedef int each_reflog_ent_fn(
289 unsigned char *old_sha1, unsigned char *new_sha1,
290 const char *committer, unsigned long timestamp,
291 int tz, const char *msg, void *cb_data);
292
293 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
294 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
295
296 /*
297 * Calls the specified function for each reflog file until it returns nonzero,
298 * and returns the value
299 */
300 int for_each_reflog(each_ref_fn fn, void *cb_data);
301
302 #define REFNAME_ALLOW_ONELEVEL 1
303 #define REFNAME_REFSPEC_PATTERN 2
304
305 /*
306 * Return 0 iff refname has the correct format for a refname according
307 * to the rules described in Documentation/git-check-ref-format.txt.
308 * If REFNAME_ALLOW_ONELEVEL is set in flags, then accept one-level
309 * reference names. If REFNAME_REFSPEC_PATTERN is set in flags, then
310 * allow a single "*" wildcard character in the refspec. No leading or
311 * repeated slashes are accepted.
312 */
313 int check_refname_format(const char *refname, int flags);
314
315 const char *prettify_refname(const char *refname);
316
317 char *shorten_unambiguous_ref(const char *refname, int strict);
318
319 /** rename ref, return 0 on success **/
320 int rename_ref(const char *oldref, const char *newref, const char *logmsg);
321
322 int create_symref(const char *refname, const char *target, const char *logmsg);
323
324 /*
325 * Update HEAD of the specified gitdir.
326 * Similar to create_symref("relative-git-dir/HEAD", target, NULL), but
327 * this can update the main working tree's HEAD regardless of where
328 * $GIT_DIR points to.
329 * Return 0 if successful, non-zero otherwise.
330 * */
331 int set_worktree_head_symref(const char *gitdir, const char *target);
332
333 enum action_on_err {
334 UPDATE_REFS_MSG_ON_ERR,
335 UPDATE_REFS_DIE_ON_ERR,
336 UPDATE_REFS_QUIET_ON_ERR
337 };
338
339 /*
340 * Begin a reference transaction. The reference transaction must
341 * be freed by calling ref_transaction_free().
342 */
343 struct ref_transaction *ref_transaction_begin(struct strbuf *err);
344
345 /*
346 * Reference transaction updates
347 *
348 * The following four functions add a reference check or update to a
349 * ref_transaction. They have some common similar parameters:
350 *
351 * transaction -- a pointer to an open ref_transaction, obtained
352 * from ref_transaction_begin().
353 *
354 * refname -- the name of the reference to be affected.
355 *
356 * flags -- flags affecting the update, passed to
357 * update_ref_lock(). Can be REF_NODEREF, which means that
358 * symbolic references should not be followed.
359 *
360 * msg -- a message describing the change (for the reflog).
361 *
362 * err -- a strbuf for receiving a description of any error that
363 * might have occured.
364 *
365 * The functions make internal copies of refname and msg, so the
366 * caller retains ownership of these parameters.
367 *
368 * The functions return 0 on success and non-zero on failure. A
369 * failure means that the transaction as a whole has failed and needs
370 * to be rolled back.
371 */
372
373 /*
374 * Add a reference update to transaction. new_sha1 is the value that
375 * the reference should have after the update, or null_sha1 if it
376 * should be deleted. If new_sha1 is NULL, then the reference is not
377 * changed at all. old_sha1 is the value that the reference must have
378 * before the update, or null_sha1 if it must not have existed
379 * beforehand. The old value is checked after the lock is taken to
380 * prevent races. If the old value doesn't agree with old_sha1, the
381 * whole transaction fails. If old_sha1 is NULL, then the previous
382 * value is not checked.
383 *
384 * See the above comment "Reference transaction updates" for more
385 * information.
386 */
387 int ref_transaction_update(struct ref_transaction *transaction,
388 const char *refname,
389 const unsigned char *new_sha1,
390 const unsigned char *old_sha1,
391 unsigned int flags, const char *msg,
392 struct strbuf *err);
393
394 /*
395 * Add a reference creation to transaction. new_sha1 is the value that
396 * the reference should have after the update; it must not be
397 * null_sha1. It is verified that the reference does not exist
398 * already.
399 *
400 * See the above comment "Reference transaction updates" for more
401 * information.
402 */
403 int ref_transaction_create(struct ref_transaction *transaction,
404 const char *refname,
405 const unsigned char *new_sha1,
406 unsigned int flags, const char *msg,
407 struct strbuf *err);
408
409 /*
410 * Add a reference deletion to transaction. If old_sha1 is non-NULL,
411 * then it holds the value that the reference should have had before
412 * the update (which must not be null_sha1).
413 *
414 * See the above comment "Reference transaction updates" for more
415 * information.
416 */
417 int ref_transaction_delete(struct ref_transaction *transaction,
418 const char *refname,
419 const unsigned char *old_sha1,
420 unsigned int flags, const char *msg,
421 struct strbuf *err);
422
423 /*
424 * Verify, within a transaction, that refname has the value old_sha1,
425 * or, if old_sha1 is null_sha1, then verify that the reference
426 * doesn't exist. old_sha1 must be non-NULL.
427 *
428 * See the above comment "Reference transaction updates" for more
429 * information.
430 */
431 int ref_transaction_verify(struct ref_transaction *transaction,
432 const char *refname,
433 const unsigned char *old_sha1,
434 unsigned int flags,
435 struct strbuf *err);
436
437 /*
438 * Commit all of the changes that have been queued in transaction, as
439 * atomically as possible.
440 *
441 * Returns 0 for success, or one of the below error codes for errors.
442 */
443 /* Naming conflict (for example, the ref names A and A/B conflict). */
444 #define TRANSACTION_NAME_CONFLICT -1
445 /* All other errors. */
446 #define TRANSACTION_GENERIC_ERROR -2
447 int ref_transaction_commit(struct ref_transaction *transaction,
448 struct strbuf *err);
449
450 /*
451 * Like ref_transaction_commit(), but optimized for creating
452 * references when originally initializing a repository (e.g., by "git
453 * clone"). It writes the new references directly to packed-refs
454 * without locking the individual references.
455 *
456 * It is a bug to call this function when there might be other
457 * processes accessing the repository or if there are existing
458 * references that might conflict with the ones being created. All
459 * old_sha1 values must either be absent or NULL_SHA1.
460 */
461 int initial_ref_transaction_commit(struct ref_transaction *transaction,
462 struct strbuf *err);
463
464 /*
465 * Free an existing transaction and all associated data.
466 */
467 void ref_transaction_free(struct ref_transaction *transaction);
468
469 /**
470 * Lock, update, and unlock a single reference. This function
471 * basically does a transaction containing a single call to
472 * ref_transaction_update(). The parameters to this function have the
473 * same meaning as the corresponding parameters to
474 * ref_transaction_update(). Handle errors as requested by the `onerr`
475 * argument.
476 */
477 int update_ref(const char *msg, const char *refname,
478 const unsigned char *new_sha1, const unsigned char *old_sha1,
479 unsigned int flags, enum action_on_err onerr);
480
481 int parse_hide_refs_config(const char *var, const char *value, const char *);
482
483 /*
484 * Check whether a ref is hidden. If no namespace is set, both the first and
485 * the second parameter point to the full ref name. If a namespace is set and
486 * the ref is inside that namespace, the first parameter is a pointer to the
487 * name of the ref with the namespace prefix removed. If a namespace is set and
488 * the ref is outside that namespace, the first parameter is NULL. The second
489 * parameter always points to the full ref name.
490 */
491 int ref_is_hidden(const char *, const char *);
492
493 enum ref_type {
494 REF_TYPE_PER_WORKTREE,
495 REF_TYPE_PSEUDOREF,
496 REF_TYPE_NORMAL,
497 };
498
499 enum ref_type ref_type(const char *refname);
500
501 enum expire_reflog_flags {
502 EXPIRE_REFLOGS_DRY_RUN = 1 << 0,
503 EXPIRE_REFLOGS_UPDATE_REF = 1 << 1,
504 EXPIRE_REFLOGS_VERBOSE = 1 << 2,
505 EXPIRE_REFLOGS_REWRITE = 1 << 3
506 };
507
508 /*
509 * The following interface is used for reflog expiration. The caller
510 * calls reflog_expire(), supplying it with three callback functions,
511 * of the following types. The callback functions define the
512 * expiration policy that is desired.
513 *
514 * reflog_expiry_prepare_fn -- Called once after the reference is
515 * locked.
516 *
517 * reflog_expiry_should_prune_fn -- Called once for each entry in the
518 * existing reflog. It should return true iff that entry should be
519 * pruned.
520 *
521 * reflog_expiry_cleanup_fn -- Called once before the reference is
522 * unlocked again.
523 */
524 typedef void reflog_expiry_prepare_fn(const char *refname,
525 const unsigned char *sha1,
526 void *cb_data);
527 typedef int reflog_expiry_should_prune_fn(unsigned char *osha1,
528 unsigned char *nsha1,
529 const char *email,
530 unsigned long timestamp, int tz,
531 const char *message, void *cb_data);
532 typedef void reflog_expiry_cleanup_fn(void *cb_data);
533
534 /*
535 * Expire reflog entries for the specified reference. sha1 is the old
536 * value of the reference. flags is a combination of the constants in
537 * enum expire_reflog_flags. The three function pointers are described
538 * above. On success, return zero.
539 */
540 int reflog_expire(const char *refname, const unsigned char *sha1,
541 unsigned int flags,
542 reflog_expiry_prepare_fn prepare_fn,
543 reflog_expiry_should_prune_fn should_prune_fn,
544 reflog_expiry_cleanup_fn cleanup_fn,
545 void *policy_cb_data);
546
547 #endif /* REFS_H */