1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /* A reference which points to an arbitrary object. */
18 struct got_reference;
19 
20 /* Well-known reference names. */
21 #define GOT_REF_HEAD		"HEAD"
22 #define GOT_REF_ORIG_HEAD	"ORIG_HEAD"
23 #define GOT_REF_MERGE_HEAD	"MERGE_HEAD"
24 #define GOT_REF_FETCH_HEAD	"FETCH_HEAD"
25 
26 struct got_repository;
27 struct got_object_id;
28 
29 /* Determine whether a given reference name is valid. */
30 int got_ref_name_is_valid(const char *);
31 
32 /*
33  * Attempt to open the reference with the provided name in a repository.
34  * The caller must dispose of the reference with got_ref_close().
35  * Optionally, the underlying reference file can be locked before it is opened
36  * to prevent concurrent modification of the reference, in which case the file
37  * must be unlocked with got_ref_unlock() before got_ref_close() is called.
38  */
39 const struct got_error *got_ref_open(struct got_reference **,
40     struct got_repository *, const char *, int);
41 
42 /*
43  * Allocate a new reference for a given object ID.
44  * The caller must dispose of it with got_ref_close().
45  */
46 const struct got_error *got_ref_alloc(struct got_reference **, const char *,
47     struct got_object_id *);
48 
49 /*
50  * Allocate a new symbolic reference which points at a given reference.
51  * The caller must dispose of it with got_ref_close().
52  */
53 const struct got_error *got_ref_alloc_symref(struct got_reference **,
54     const char *, struct got_reference *);
55 
56 /* Dispose of a reference. */
57 void got_ref_close(struct got_reference *);
58 
59 /* Get the name of the reference. */
60 const char *got_ref_get_name(struct got_reference *);
61 
62 /* Get the name of the reference which a symoblic reference points at. */
63 const char *got_ref_get_symref_target(struct got_reference *);
64 
65 /* Get the last modification timestamp of the reference. */
66 time_t got_ref_get_mtime(struct got_reference *);
67 
68 /*
69  * Create a duplicate copy of a reference.
70  * The caller must dispose of this copy with got_ref_close().
71  */
72 struct got_reference *got_ref_dup(struct got_reference *);
73 
74 /* Attempt to resolve a symbolic reference to a non-symbolic one. */
75 const struct got_error *got_ref_resolve_symbolic(struct got_reference **,
76     struct got_repository *, struct got_reference *);
77 
78 /* Attempt to resolve a reference (symbolic or not) to an object ID. */
79 const struct got_error *got_ref_resolve(struct got_object_id **,
80     struct got_repository *, struct got_reference *);
81 
82 /*
83  * Return a string representation of a reference.
84  * The caller must dispose of it with free(3).
85  */
86 char *got_ref_to_str(struct got_reference *);
87 
88 /* List of references. */
89 struct got_reflist_entry {
90 	TAILQ_ENTRY(got_reflist_entry) entry;
91 	struct got_reference *ref;
92 };
93 TAILQ_HEAD(got_reflist_head, got_reflist_entry);
94 
95 /* Duplicate a reference list entry. Caller must dispose of it with free(3). */
96 const struct got_error *got_reflist_entry_dup(struct got_reflist_entry **,
97     struct got_reflist_entry *);
98 
99 /* A function which compares two references. Used with got_ref_list(). */
100 typedef const struct got_error *(*got_ref_cmp_cb)(void *, int *,
101     struct got_reference *, struct got_reference *);
102 
103 /* An implementation of got_ref_cmp_cb which compares two references by name. */
104 const struct got_error *got_ref_cmp_by_name(void *, int *,
105     struct got_reference *, struct got_reference *);
106 
107 /* An implementation of got_ref_cmp_cb which compares two tags. */
108 const struct got_error *got_ref_cmp_tags(void *, int *,
109     struct got_reference *, struct got_reference *);
110 
111 /*
112  * An implementation of got_ref_cmp_cb which compares commit timestamps.
113  * Requires a struct got_repository * as the void * argument.
114  */
115 const struct got_error *got_ref_cmp_by_commit_timestamp_descending(void *,
116     int *, struct got_reference *, struct got_reference *);
117 
118 /*
119  * Append all known references to a caller-provided ref list head.
120  * Optionally limit references returned to those within a given
121  * reference namespace. Sort the list with the provided reference comparison
122  * function, usually got_ref_cmp_by_name().
123  */
124 const struct got_error *got_ref_list(struct got_reflist_head *,
125     struct got_repository *, const char *, got_ref_cmp_cb, void *);
126 
127 /* Free all references on a ref list. */
128 void got_ref_list_free(struct got_reflist_head *);
129 
130 /*
131  * Insert a reference into a reference list.
132  * Return a pointer to the newly allocated list entry in *newp.
133  * If *newp is NULL and no error occured then the specified reference was
134  * already an element of the list. If *newp is not NULL then the reference
135  * was shallow-copied onto the list and should no longer be closed with
136  * got_ref_close(). Instead it will be closed along with other list
137  * elements by got_ref_list_free().
138  */
139 const struct got_error *
140 got_reflist_insert(struct got_reflist_entry **newp, struct got_reflist_head *refs,
141     struct got_reference *ref, got_ref_cmp_cb cmp_cb, void *cmp_arg);
142 
143 /* Sort a list of references with the provided comparison callback. */
144 const struct got_error *
145 got_reflist_sort(struct got_reflist_head *refs, got_ref_cmp_cb cmp_cb,
146     void *cmp_arg);
147 
148 /* Indicate whether the provided reference is symbolic (points at another
149  * refernce) or not (points at an object ID). */
150 int got_ref_is_symbolic(struct got_reference *);
151 
152 /* Change the object ID a reference points to. */
153 const struct got_error *
154 got_ref_change_ref(struct got_reference *, struct got_object_id *);
155 
156 /* Change the reference name a symbolic reference points to. */
157 const struct got_error *got_ref_change_symref(struct got_reference *,
158     const char *);
159 
160 /*
161  * Change a symbolic reference into a regular reference which points to
162  * the provided object ID.
163  */
164 const struct got_error *got_ref_change_symref_to_ref(struct got_reference *,
165     struct got_object_id *);
166 
167 /* Write a reference to its on-disk path in the repository. */
168 const struct got_error *got_ref_write(struct got_reference *,
169     struct got_repository *);
170 
171 /* Delete a reference from its on-disk path in the repository. */
172 const struct got_error *got_ref_delete(struct got_reference *,
173     struct got_repository *);
174 
175 /* Unlock a reference which was opened in locked state. */
176 const struct got_error *got_ref_unlock(struct got_reference *);
177 
178 /* Map object IDs to references. */
179 struct got_reflist_object_id_map;
180 
181 /*
182  * Create and populate an object ID map for a given list of references.
183  * Map entries will contain deep-copies of elements of the reflist.
184  * The caller must dispose of the map with got_reflist_object_id_map_free().
185  */
186 const struct got_error *got_reflist_object_id_map_create(
187     struct got_reflist_object_id_map **, struct got_reflist_head *, 
188     struct got_repository *);
189 
190 /*
191  * Return a list of references which correspond to a given object ID.
192  * The returned list must be considered read-only.
193  * The caller must _not_ call free(3) on the returned pointer!
194  * If no references are associated with the ID, return NULL.
195  */
196 struct got_reflist_head *
197 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *,
198     struct got_object_id *);
199 
200 /* Free the specified object ID map. */
201 void got_reflist_object_id_map_free(struct got_reflist_object_id_map *);