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 /*
30  * Attempt to open the reference with the provided name in a repository.
31  * The caller must dispose of the reference with got_ref_close().
32  * Optionally, the underlying reference file can be locked before it is opened
33  * to prevent concurrent modification of the reference, in which case the file
34  * must be unlocked with got_ref_unlock() before got_ref_close() is called.
35  */
36 const struct got_error *got_ref_open(struct got_reference **,
37     struct got_repository *, const char *, int);
38 
39 /*
40  * Allocate a new reference for a given object ID.
41  * The caller must dispose of it with got_ref_close().
42  */
43 const struct got_error *got_ref_alloc(struct got_reference **, const char *,
44     struct got_object_id *);
45 
46 /*
47  * Allocate a new symbolic reference which points at a given reference.
48  * The caller must dispose of it with got_ref_close().
49  */
50 const struct got_error *got_ref_alloc_symref(struct got_reference **,
51     const char *, struct got_reference *);
52 
53 /* Dispose of a reference. */
54 void got_ref_close(struct got_reference *);
55 
56 /* Get the name of the reference. */
57 const char *got_ref_get_name(struct got_reference *);
58 
59 /* Get the name of the reference which a symoblic reference points at. */
60 const char *got_ref_get_symref_target(struct got_reference *);
61 
62 /*
63  * Create a duplicate copy of a reference.
64  * The caller must dispose of this copy with got_ref_close().
65  */
66 struct got_reference *got_ref_dup(struct got_reference *);
67 
68 /* Attempt to resolve a reference to an object ID. */
69 const struct got_error *got_ref_resolve(struct got_object_id **,
70     struct got_repository *, struct got_reference *);
71 
72 /*
73  * Return a string representation of a reference.
74  * The caller must dispose of it with free(3).
75  */
76 char *got_ref_to_str(struct got_reference *);
77 
78 /* List of references. */
79 struct got_reflist_entry {
80 	TAILQ_ENTRY(got_reflist_entry) entry;
81 	struct got_reference *ref;
82 };
83 TAILQ_HEAD(got_reflist_head, got_reflist_entry);
84 
85 /* Duplicate a reference list entry. Caller must dispose of it with free(3). */
86 const struct got_error *got_reflist_entry_dup(struct got_reflist_entry **,
87     struct got_reflist_entry *);
88 
89 /* A function which compares two references. Used with got_ref_list(). */
90 typedef const struct got_error *(*got_ref_cmp_cb)(void *, int *,
91     struct got_reference *, struct got_reference *);
92 
93 /* An implementation of got_ref_cmp_cb which compares two references by name. */
94 const struct got_error *got_ref_cmp_by_name(void *, int *,
95     struct got_reference *, struct got_reference *);
96 
97 /* An implementation of got_ref_cmp_cb which compares two tags. */
98 const struct got_error *got_ref_cmp_tags(void *, int *,
99     struct got_reference *, struct got_reference *);
100 
101 /*
102  * An implementation of got_ref_cmp_cb which compares commit timestamps.
103  * Requires a struct got_repository * as the void * argument.
104  */
105 const struct got_error *got_ref_cmp_by_commit_timestamp_descending(void *,
106     int *, struct got_reference *, struct got_reference *);
107 
108 /*
109  * Append all known references to a caller-provided ref list head.
110  * Optionally limit references returned to those within a given
111  * reference namespace. Sort the list with the provided reference comparison
112  * function, usually got_ref_cmp_by_name().
113  */
114 const struct got_error *got_ref_list(struct got_reflist_head *,
115     struct got_repository *, const char *, got_ref_cmp_cb, void *);
116 
117 /* Free all references on a ref list. */
118 void got_ref_list_free(struct got_reflist_head *);
119 
120 /* Indicate whether the provided reference is symbolic (points at another
121  * refernce) or not (points at an object ID). */
122 int got_ref_is_symbolic(struct got_reference *);
123 
124 /* Change the object ID a reference points to. */
125 const struct got_error *
126 got_ref_change_ref(struct got_reference *, struct got_object_id *);
127 
128 /* Change the reference name a symbolic reference points to. */
129 const struct got_error *got_ref_change_symref(struct got_reference *,
130     const char *);
131 
132 /*
133  * Change a symbolic reference into a regular reference which points to
134  * the provided object ID.
135  */
136 const struct got_error *got_ref_change_symref_to_ref(struct got_reference *,
137     struct got_object_id *);
138 
139 /* Write a reference to its on-disk path in the repository. */
140 const struct got_error *got_ref_write(struct got_reference *,
141     struct got_repository *);
142 
143 /* Delete a reference from its on-disk path in the repository. */
144 const struct got_error *got_ref_delete(struct got_reference *,
145     struct got_repository *);
146 
147 /* Unlock a reference which was opened in locked state. */
148 const struct got_error *got_ref_unlock(struct got_reference *);
149 
150 /* Map object IDs to references. */
151 struct got_reflist_object_id_map;
152 
153 /*
154  * Create and populate an object ID map for a given list of references.
155  * Map entries will contain deep-copies of elements of the reflist.
156  * The caller must dispose of the map with got_reflist_object_id_map_free().
157  */
158 const struct got_error *got_reflist_object_id_map_create(
159     struct got_reflist_object_id_map **, struct got_reflist_head *, 
160     struct got_repository *);
161 
162 /*
163  * Return a list of references which correspond to a given object ID.
164  * The returned list must be considered read-only.
165  * The caller must _not_ call free(3) on the returned pointer!
166  * If no references are associated with the ID, return NULL.
167  */
168 struct got_reflist_head *
169 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *,
170     struct got_object_id *);
171 
172 /* Free the specified object ID map. */
173 void got_reflist_object_id_map_free(struct got_reflist_object_id_map *);