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 /* Get the last modification timestamp of the reference. */
63 time_t got_ref_get_mtime(struct got_reference *);
64 
65 /*
66  * Create a duplicate copy of a reference.
67  * The caller must dispose of this copy with got_ref_close().
68  */
69 struct got_reference *got_ref_dup(struct got_reference *);
70 
71 /* Attempt to resolve a reference to an object ID. */
72 const struct got_error *got_ref_resolve(struct got_object_id **,
73     struct got_repository *, struct got_reference *);
74 
75 /*
76  * Return a string representation of a reference.
77  * The caller must dispose of it with free(3).
78  */
79 char *got_ref_to_str(struct got_reference *);
80 
81 /* List of references. */
82 struct got_reflist_entry {
83 	TAILQ_ENTRY(got_reflist_entry) entry;
84 	struct got_reference *ref;
85 };
86 TAILQ_HEAD(got_reflist_head, got_reflist_entry);
87 
88 /* Duplicate a reference list entry. Caller must dispose of it with free(3). */
89 const struct got_error *got_reflist_entry_dup(struct got_reflist_entry **,
90     struct got_reflist_entry *);
91 
92 /* A function which compares two references. Used with got_ref_list(). */
93 typedef const struct got_error *(*got_ref_cmp_cb)(void *, int *,
94     struct got_reference *, struct got_reference *);
95 
96 /* An implementation of got_ref_cmp_cb which compares two references by name. */
97 const struct got_error *got_ref_cmp_by_name(void *, int *,
98     struct got_reference *, struct got_reference *);
99 
100 /* An implementation of got_ref_cmp_cb which compares two tags. */
101 const struct got_error *got_ref_cmp_tags(void *, int *,
102     struct got_reference *, struct got_reference *);
103 
104 /*
105  * An implementation of got_ref_cmp_cb which compares commit timestamps.
106  * Requires a struct got_repository * as the void * argument.
107  */
108 const struct got_error *got_ref_cmp_by_commit_timestamp_descending(void *,
109     int *, struct got_reference *, struct got_reference *);
110 
111 /*
112  * Append all known references to a caller-provided ref list head.
113  * Optionally limit references returned to those within a given
114  * reference namespace. Sort the list with the provided reference comparison
115  * function, usually got_ref_cmp_by_name().
116  */
117 const struct got_error *got_ref_list(struct got_reflist_head *,
118     struct got_repository *, const char *, got_ref_cmp_cb, void *);
119 
120 /* Free all references on a ref list. */
121 void got_ref_list_free(struct got_reflist_head *);
122 
123 /*
124  * Insert a reference into a reference list.
125  * Return a pointer to the newly allocated list entry in *newp.
126  * If *newp is NULL and no error occured then the specified reference was
127  * already an element of the list. If *newp is not NULL then the reference
128  * was shallow-copied onto the list and should no longer be closed with
129  * got_ref_close(). Instead it will be closed along with other list
130  * elements by got_ref_list_free().
131  */
132 const struct got_error *
133 got_reflist_insert(struct got_reflist_entry **newp, struct got_reflist_head *refs,
134     struct got_reference *ref, struct got_repository *repo,
135     got_ref_cmp_cb cmp_cb, void *cmp_arg);
136 
137 /* Indicate whether the provided reference is symbolic (points at another
138  * refernce) or not (points at an object ID). */
139 int got_ref_is_symbolic(struct got_reference *);
140 
141 /* Change the object ID a reference points to. */
142 const struct got_error *
143 got_ref_change_ref(struct got_reference *, struct got_object_id *);
144 
145 /* Change the reference name a symbolic reference points to. */
146 const struct got_error *got_ref_change_symref(struct got_reference *,
147     const char *);
148 
149 /*
150  * Change a symbolic reference into a regular reference which points to
151  * the provided object ID.
152  */
153 const struct got_error *got_ref_change_symref_to_ref(struct got_reference *,
154     struct got_object_id *);
155 
156 /* Write a reference to its on-disk path in the repository. */
157 const struct got_error *got_ref_write(struct got_reference *,
158     struct got_repository *);
159 
160 /* Delete a reference from its on-disk path in the repository. */
161 const struct got_error *got_ref_delete(struct got_reference *,
162     struct got_repository *);
163 
164 /* Unlock a reference which was opened in locked state. */
165 const struct got_error *got_ref_unlock(struct got_reference *);
166 
167 /* Map object IDs to references. */
168 struct got_reflist_object_id_map;
169 
170 /*
171  * Create and populate an object ID map for a given list of references.
172  * Map entries will contain deep-copies of elements of the reflist.
173  * The caller must dispose of the map with got_reflist_object_id_map_free().
174  */
175 const struct got_error *got_reflist_object_id_map_create(
176     struct got_reflist_object_id_map **, struct got_reflist_head *, 
177     struct got_repository *);
178 
179 /*
180  * Return a list of references which correspond to a given object ID.
181  * The returned list must be considered read-only.
182  * The caller must _not_ call free(3) on the returned pointer!
183  * If no references are associated with the ID, return NULL.
184  */
185 struct got_reflist_head *
186 got_reflist_object_id_map_lookup(struct got_reflist_object_id_map *,
187     struct got_object_id *);
188 
189 /* Free the specified object ID map. */
190 void got_reflist_object_id_map_free(struct got_reflist_object_id_map *);