Documentation/describe: improve one-line summary
[git.git] / refs.h
blob2bc3556874a7b1cbccb4cebf4e3dc2fa13cc780f
1 #ifndef REFS_H
2 #define REFS_H
4 struct ref_lock {
5 char *ref_name;
6 char *orig_ref_name;
7 struct lock_file *lk;
8 unsigned char old_sha1[20];
9 int lock_fd;
10 int force_write;
14 * A ref_transaction represents a collection of ref updates
15 * that should succeed or fail together.
17 * Calling sequence
18 * ----------------
19 * - Allocate and initialize a `struct ref_transaction` by calling
20 * `ref_transaction_begin()`.
22 * - List intended ref updates by calling functions like
23 * `ref_transaction_update()` and `ref_transaction_create()`.
25 * - Call `ref_transaction_commit()` to execute the transaction.
26 * If this succeeds, the ref updates will have taken place and
27 * the transaction cannot be rolled back.
29 * - At any time call `ref_transaction_free()` to discard the
30 * transaction and free associated resources. In particular,
31 * this rolls back the transaction if it has not been
32 * successfully committed.
34 * Error handling
35 * --------------
37 * On error, transaction functions append a message about what
38 * went wrong to the 'err' argument. The message mentions what
39 * ref was being updated (if any) when the error occurred so it
40 * can be passed to 'die' or 'error' as-is.
42 * The message is appended to err without first clearing err.
43 * err will not be '\n' terminated.
45 struct ref_transaction;
48 * Bit values set in the flags argument passed to each_ref_fn():
51 /* Reference is a symbolic reference. */
52 #define REF_ISSYMREF 0x01
54 /* Reference is a packed reference. */
55 #define REF_ISPACKED 0x02
58 * Reference cannot be resolved to an object name: dangling symbolic
59 * reference (directly or indirectly), corrupt reference file,
60 * reference exists but name is bad, or symbolic reference refers to
61 * ill-formatted reference name.
63 #define REF_ISBROKEN 0x04
66 * Reference name is not well formed.
68 * See git-check-ref-format(1) for the definition of well formed ref names.
70 #define REF_BAD_NAME 0x08
73 * The signature for the callback function for the for_each_*()
74 * functions below. The memory pointed to by the refname and sha1
75 * arguments is only guaranteed to be valid for the duration of a
76 * single callback invocation.
78 typedef int each_ref_fn(const char *refname,
79 const unsigned char *sha1, int flags, void *cb_data);
82 * The following functions invoke the specified callback function for
83 * each reference indicated. If the function ever returns a nonzero
84 * value, stop the iteration and return that value. Please note that
85 * it is not safe to modify references while an iteration is in
86 * progress, unless the same callback function invocation that
87 * modifies the reference also returns a nonzero value to immediately
88 * stop the iteration.
90 extern int head_ref(each_ref_fn, void *);
91 extern int for_each_ref(each_ref_fn, void *);
92 extern int for_each_ref_in(const char *, each_ref_fn, void *);
93 extern int for_each_tag_ref(each_ref_fn, void *);
94 extern int for_each_branch_ref(each_ref_fn, void *);
95 extern int for_each_remote_ref(each_ref_fn, void *);
96 extern int for_each_replace_ref(each_ref_fn, void *);
97 extern int for_each_glob_ref(each_ref_fn, const char *pattern, void *);
98 extern int for_each_glob_ref_in(each_ref_fn, const char *pattern, const char* prefix, void *);
100 extern int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
101 extern int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
102 extern int for_each_ref_in_submodule(const char *submodule, const char *prefix,
103 each_ref_fn fn, void *cb_data);
104 extern int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
105 extern int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
106 extern int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data);
108 extern int head_ref_namespaced(each_ref_fn fn, void *cb_data);
109 extern int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);
111 static inline const char *has_glob_specials(const char *pattern)
113 return strpbrk(pattern, "?*[");
116 /* can be used to learn about broken ref and symref */
117 extern int for_each_rawref(each_ref_fn, void *);
119 extern void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname);
120 extern void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames);
123 * Lock the packed-refs file for writing. Flags is passed to
124 * hold_lock_file_for_update(). Return 0 on success.
125 * Errno is set to something meaningful on error.
127 extern int lock_packed_refs(int flags);
130 * Add a reference to the in-memory packed reference cache. This may
131 * only be called while the packed-refs file is locked (see
132 * lock_packed_refs()). To actually write the packed-refs file, call
133 * commit_packed_refs().
135 extern void add_packed_ref(const char *refname, const unsigned char *sha1);
138 * Write the current version of the packed refs cache from memory to
139 * disk. The packed-refs file must already be locked for writing (see
140 * lock_packed_refs()). Return zero on success.
141 * Sets errno to something meaningful on error.
143 extern int commit_packed_refs(void);
146 * Rollback the lockfile for the packed-refs file, and discard the
147 * in-memory packed reference cache. (The packed-refs file will be
148 * read anew if it is needed again after this function is called.)
150 extern void rollback_packed_refs(void);
153 * Flags for controlling behaviour of pack_refs()
154 * PACK_REFS_PRUNE: Prune loose refs after packing
155 * PACK_REFS_ALL: Pack _all_ refs, not just tags and already packed refs
157 #define PACK_REFS_PRUNE 0x0001
158 #define PACK_REFS_ALL 0x0002
161 * Write a packed-refs file for the current repository.
162 * flags: Combination of the above PACK_REFS_* flags.
164 int pack_refs(unsigned int flags);
166 extern int repack_without_refs(const char **refnames, int n,
167 struct strbuf *err);
169 extern int ref_exists(const char *);
171 extern int is_branch(const char *refname);
174 * If refname is a non-symbolic reference that refers to a tag object,
175 * and the tag can be (recursively) dereferenced to a non-tag object,
176 * store the SHA1 of the referred-to object to sha1 and return 0. If
177 * any of these conditions are not met, return a non-zero value.
178 * Symbolic references are considered unpeelable, even if they
179 * ultimately resolve to a peelable tag.
181 extern int peel_ref(const char *refname, unsigned char *sha1);
184 * Flags controlling lock_any_ref_for_update(), ref_transaction_update(),
185 * ref_transaction_create(), etc.
186 * REF_NODEREF: act on the ref directly, instead of dereferencing
187 * symbolic references.
188 * REF_DELETING: tolerate broken refs
190 * Flags >= 0x100 are reserved for internal use.
192 #define REF_NODEREF 0x01
193 #define REF_DELETING 0x02
195 * This function sets errno to something meaningful on failure.
197 extern struct ref_lock *lock_any_ref_for_update(const char *refname,
198 const unsigned char *old_sha1,
199 int flags, int *type_p);
201 /** Close the file descriptor owned by a lock and return the status */
202 extern int close_ref(struct ref_lock *lock);
204 /** Close and commit the ref locked by the lock */
205 extern int commit_ref(struct ref_lock *lock);
207 /** Release any lock taken but not written. **/
208 extern void unlock_ref(struct ref_lock *lock);
211 * Setup reflog before using. Set errno to something meaningful on failure.
213 int log_ref_setup(const char *refname, char *logfile, int bufsize);
215 /** Reads log for the value of ref during at_time. **/
216 extern int read_ref_at(const char *refname, unsigned int flags,
217 unsigned long at_time, int cnt,
218 unsigned char *sha1, char **msg,
219 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);
221 /** Check if a particular reflog exists */
222 extern int reflog_exists(const char *refname);
224 /** Delete a reflog */
225 extern int delete_reflog(const char *refname);
227 /* iterate over reflog entries */
228 typedef int each_reflog_ent_fn(unsigned char *osha1, unsigned char *nsha1, const char *, unsigned long, int, const char *, void *);
229 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
230 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
233 * Calls the specified function for each reflog file until it returns nonzero,
234 * and returns the value
236 extern int for_each_reflog(each_ref_fn, void *);
238 #define REFNAME_ALLOW_ONELEVEL 1
239 #define REFNAME_REFSPEC_PATTERN 2
242 * Return 0 iff refname has the correct format for a refname according
243 * to the rules described in Documentation/git-check-ref-format.txt.
244 * If REFNAME_ALLOW_ONELEVEL is set in flags, then accept one-level
245 * reference names. If REFNAME_REFSPEC_PATTERN is set in flags, then
246 * allow a "*" wildcard character in place of one of the name
247 * components. No leading or repeated slashes are accepted.
249 extern int check_refname_format(const char *refname, int flags);
251 extern const char *prettify_refname(const char *refname);
252 extern char *shorten_unambiguous_ref(const char *refname, int strict);
254 /** rename ref, return 0 on success **/
255 extern int rename_ref(const char *oldref, const char *newref, const char *logmsg);
258 * Resolve refname in the nested "gitlink" repository that is located
259 * at path. If the resolution is successful, return 0 and set sha1 to
260 * the name of the object; otherwise, return a non-zero value.
262 extern int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1);
264 enum action_on_err {
265 UPDATE_REFS_MSG_ON_ERR,
266 UPDATE_REFS_DIE_ON_ERR,
267 UPDATE_REFS_QUIET_ON_ERR
271 * Begin a reference transaction. The reference transaction must
272 * be freed by calling ref_transaction_free().
274 struct ref_transaction *ref_transaction_begin(struct strbuf *err);
277 * The following functions add a reference check or update to a
278 * ref_transaction. In all of them, refname is the name of the
279 * reference to be affected. The functions make internal copies of
280 * refname and msg, so the caller retains ownership of these parameters.
281 * flags can be REF_NODEREF; it is passed to update_ref_lock().
285 * Add a reference update to transaction. new_sha1 is the value that
286 * the reference should have after the update, or zeros if it should
287 * be deleted. If have_old is true, then old_sha1 holds the value
288 * that the reference should have had before the update, or zeros if
289 * it must not have existed beforehand.
290 * Function returns 0 on success and non-zero on failure. A failure to update
291 * means that the transaction as a whole has failed and will need to be
292 * rolled back.
294 int ref_transaction_update(struct ref_transaction *transaction,
295 const char *refname,
296 const unsigned char *new_sha1,
297 const unsigned char *old_sha1,
298 int flags, int have_old, const char *msg,
299 struct strbuf *err);
302 * Add a reference creation to transaction. new_sha1 is the value
303 * that the reference should have after the update; it must not be the
304 * null SHA-1. It is verified that the reference does not exist
305 * already.
306 * Function returns 0 on success and non-zero on failure. A failure to create
307 * means that the transaction as a whole has failed and will need to be
308 * rolled back.
310 int ref_transaction_create(struct ref_transaction *transaction,
311 const char *refname,
312 const unsigned char *new_sha1,
313 int flags, const char *msg,
314 struct strbuf *err);
317 * Add a reference deletion to transaction. If have_old is true, then
318 * old_sha1 holds the value that the reference should have had before
319 * the update (which must not be the null SHA-1).
320 * Function returns 0 on success and non-zero on failure. A failure to delete
321 * means that the transaction as a whole has failed and will need to be
322 * rolled back.
324 int ref_transaction_delete(struct ref_transaction *transaction,
325 const char *refname,
326 const unsigned char *old_sha1,
327 int flags, int have_old, const char *msg,
328 struct strbuf *err);
331 * Commit all of the changes that have been queued in transaction, as
332 * atomically as possible.
334 * Returns 0 for success, or one of the below error codes for errors.
336 /* Naming conflict (for example, the ref names A and A/B conflict). */
337 #define TRANSACTION_NAME_CONFLICT -1
338 /* All other errors. */
339 #define TRANSACTION_GENERIC_ERROR -2
340 int ref_transaction_commit(struct ref_transaction *transaction,
341 struct strbuf *err);
344 * Free an existing transaction and all associated data.
346 void ref_transaction_free(struct ref_transaction *transaction);
348 /** Lock a ref and then write its file */
349 int update_ref(const char *action, const char *refname,
350 const unsigned char *sha1, const unsigned char *oldval,
351 int flags, enum action_on_err onerr);
353 extern int parse_hide_refs_config(const char *var, const char *value, const char *);
354 extern int ref_is_hidden(const char *);
356 #endif /* REFS_H */