verify_refname_available(): adjust constness in declaration
[git/git.git] / refs / refs-internal.h
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1#ifndef REFS_REFS_INTERNAL_H
2#define REFS_REFS_INTERNAL_H
3
4/*
5 * Data structures and functions for the internal use of the refs
6 * module. Code outside of the refs module should use only the public
7 * functions defined in "refs.h", and should *not* include this file.
8 */
9
10/*
11 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
12 * refs (i.e., because the reference is about to be deleted anyway).
13 */
14#define REF_DELETING 0x02
15
16/*
17 * Used as a flag in ref_update::flags when a loose ref is being
c52ce248 18 * pruned. This flag must only be used when REF_NODEREF is set.
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19 */
20#define REF_ISPRUNING 0x04
21
22/*
23 * Used as a flag in ref_update::flags when the reference should be
24 * updated to new_sha1.
25 */
26#define REF_HAVE_NEW 0x08
27
28/*
29 * Used as a flag in ref_update::flags when old_sha1 should be
30 * checked.
31 */
32#define REF_HAVE_OLD 0x10
33
34/*
35 * Used as a flag in ref_update::flags when the lockfile needs to be
36 * committed.
37 */
38#define REF_NEEDS_COMMIT 0x20
39
40/*
41 * 0x40 is REF_FORCE_CREATE_REFLOG, so skip it if you're adding a
42 * value to ref_update::flags
43 */
44
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45/*
46 * Used as a flag in ref_update::flags when we want to log a ref
47 * update but not actually perform it. This is used when a symbolic
48 * ref update is split up.
49 */
50#define REF_LOG_ONLY 0x80
51
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52/*
53 * Return true iff refname is minimally safe. "Safe" here means that
54 * deleting a loose reference by this name will not do any damage, for
55 * example by causing a file that is not a reference to be deleted.
56 * This function does not check that the reference name is legal; for
57 * that, use check_refname_format().
58 *
59 * We consider a refname that starts with "refs/" to be safe as long
60 * as any ".." components that it might contain do not escape "refs/".
61 * Names that do not start with "refs/" are considered safe iff they
62 * consist entirely of upper case characters and '_' (like "HEAD" and
63 * "MERGE_HEAD" but not "config" or "FOO/BAR").
64 */
65int refname_is_safe(const char *refname);
66
67enum peel_status {
68 /* object was peeled successfully: */
69 PEEL_PEELED = 0,
70
71 /*
72 * object cannot be peeled because the named object (or an
73 * object referred to by a tag in the peel chain), does not
74 * exist.
75 */
76 PEEL_INVALID = -1,
77
78 /* object cannot be peeled because it is not a tag: */
79 PEEL_NON_TAG = -2,
80
81 /* ref_entry contains no peeled value because it is a symref: */
82 PEEL_IS_SYMREF = -3,
83
84 /*
85 * ref_entry cannot be peeled because it is broken (i.e., the
86 * symbolic reference cannot even be resolved to an object
87 * name):
88 */
89 PEEL_BROKEN = -4
90};
91
92/*
93 * Peel the named object; i.e., if the object is a tag, resolve the
94 * tag recursively until a non-tag is found. If successful, store the
95 * result to sha1 and return PEEL_PEELED. If the object is not a tag
96 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
97 * and leave sha1 unchanged.
98 */
99enum peel_status peel_object(const unsigned char *name, unsigned char *sha1);
100
101/*
102 * Return 0 if a reference named refname could be created without
103 * conflicting with the name of an existing reference. Otherwise,
104 * return a negative value and write an explanation to err. If extras
105 * is non-NULL, it is a list of additional refnames with which refname
106 * is not allowed to conflict. If skip is non-NULL, ignore potential
107 * conflicts with refs in skip (e.g., because they are scheduled for
108 * deletion in the same operation). Behavior is undefined if the same
109 * name is listed in both extras and skip.
110 *
111 * Two reference names conflict if one of them exactly matches the
112 * leading components of the other; e.g., "foo/bar" conflicts with
113 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
114 * "foo/barbados".
115 *
116 * extras and skip must be sorted.
117 */
118int verify_refname_available(const char *newname,
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119 const struct string_list *extras,
120 const struct string_list *skip,
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121 struct strbuf *err);
122
123/*
124 * Copy the reflog message msg to buf, which has been allocated sufficiently
125 * large, while cleaning up the whitespaces. Especially, convert LF to space,
126 * because reflog file is one line per entry.
127 */
128int copy_reflog_msg(char *buf, const char *msg);
129
130int should_autocreate_reflog(const char *refname);
131
132/**
133 * Information needed for a single ref update. Set new_sha1 to the new
134 * value or to null_sha1 to delete the ref. To check the old value
135 * while the ref is locked, set (flags & REF_HAVE_OLD) and set
136 * old_sha1 to the old value, or to null_sha1 to ensure the ref does
137 * not exist before update.
138 */
139struct ref_update {
140 /*
141 * If (flags & REF_HAVE_NEW), set the reference to this value:
142 */
143 unsigned char new_sha1[20];
144 /*
145 * If (flags & REF_HAVE_OLD), check that the reference
146 * previously had this value:
147 */
148 unsigned char old_sha1[20];
149 /*
150 * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
151 * REF_DELETING, and REF_ISPRUNING:
152 */
153 unsigned int flags;
154 struct ref_lock *lock;
155 int type;
156 char *msg;
157 const char refname[FLEX_ARRAY];
158};
159
160/*
161 * Transaction states.
162 * OPEN: The transaction is in a valid state and can accept new updates.
163 * An OPEN transaction can be committed.
164 * CLOSED: A closed transaction is no longer active and no other operations
165 * than free can be used on it in this state.
166 * A transaction can either become closed by successfully committing
167 * an active transaction or if there is a failure while building
168 * the transaction thus rendering it failed/inactive.
169 */
170enum ref_transaction_state {
171 REF_TRANSACTION_OPEN = 0,
172 REF_TRANSACTION_CLOSED = 1
173};
174
175/*
176 * Data structure for holding a reference transaction, which can
177 * consist of checks and updates to multiple references, carried out
178 * as atomically as possible. This structure is opaque to callers.
179 */
180struct ref_transaction {
181 struct ref_update **updates;
182 size_t alloc;
183 size_t nr;
184 enum ref_transaction_state state;
185};
186
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187int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
188 const unsigned char *new_sha1, const char *msg,
189 int flags, struct strbuf *err);
190
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191/*
192 * Check for entries in extras that are within the specified
193 * directory, where dirname is a reference directory name including
194 * the trailing slash (e.g., "refs/heads/foo/"). Ignore any
195 * conflicting references that are found in skip. If there is a
196 * conflicting reference, return its name.
197 *
198 * extras and skip must be sorted lists of reference names. Either one
199 * can be NULL, signifying the empty list.
200 */
201const char *find_descendant_ref(const char *dirname,
202 const struct string_list *extras,
203 const struct string_list *skip);
204
205int rename_ref_available(const char *oldname, const char *newname);
206
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207/* We allow "recursive" symbolic refs. Only within reason, though */
208#define SYMREF_MAXDEPTH 5
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209
210/* Include broken references in a do_for_each_ref*() iteration: */
211#define DO_FOR_EACH_INCLUDE_BROKEN 0x01
212
213/*
214 * The common backend for the for_each_*ref* functions
215 */
216int do_for_each_ref(const char *submodule, const char *base,
217 each_ref_fn fn, int trim, int flags, void *cb_data);
2d0663b2 218
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219/*
220 * Read the specified reference from the filesystem or packed refs
221 * file, non-recursively. Set type to describe the reference, and:
222 *
223 * - If refname is the name of a normal reference, fill in sha1
224 * (leaving referent unchanged).
225 *
226 * - If refname is the name of a symbolic reference, write the full
227 * name of the reference to which it refers (e.g.
228 * "refs/heads/master") to referent and set the REF_ISSYMREF bit in
229 * type (leaving sha1 unchanged). The caller is responsible for
230 * validating that referent is a valid reference name.
231 *
232 * WARNING: refname might be used as part of a filename, so it is
233 * important from a security standpoint that it be safe in the sense
234 * of refname_is_safe(). Moreover, for symrefs this function sets
235 * referent to whatever the repository says, which might not be a
236 * properly-formatted or even safe reference name. NEITHER INPUT NOR
237 * OUTPUT REFERENCE NAMES ARE VALIDATED WITHIN THIS FUNCTION.
238 *
239 * Return 0 on success. If the ref doesn't exist, set errno to ENOENT
240 * and return -1. If the ref exists but is neither a symbolic ref nor
241 * a sha1, it is broken; set REF_ISBROKEN in type, set errno to
242 * EINVAL, and return -1. If there is another error reading the ref,
243 * set errno appropriately and return -1.
244 *
245 * Backend-specific flags might be set in type as well, regardless of
246 * outcome.
247 *
248 * It is OK for refname to point into referent. If so:
249 *
250 * - if the function succeeds with REF_ISSYMREF, referent will be
251 * overwritten and the memory formerly pointed to by it might be
252 * changed or even freed.
253 *
254 * - in all other cases, referent will be untouched, and therefore
255 * refname will still be valid and unchanged.
256 */
2d0663b2 257int read_raw_ref(const char *refname, unsigned char *sha1,
92b38093 258 struct strbuf *referent, unsigned int *type);
2d0663b2 259
4cb77009 260#endif /* REFS_REFS_INTERNAL_H */