cfe2a796f85ecf8dfbbb35d3232893929670b492
[git/git.git] / builtin / merge-base.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "commit.h"
4 #include "refs.h"
5 #include "diff.h"
6 #include "revision.h"
7 #include "parse-options.h"
8
9 static int show_merge_base(struct commit **rev, int rev_nr, int show_all)
10 {
11 struct commit_list *result;
12
13 result = get_merge_bases_many_dirty(rev[0], rev_nr - 1, rev + 1);
14
15 if (!result)
16 return 1;
17
18 while (result) {
19 printf("%s\n", oid_to_hex(&result->item->object.oid));
20 if (!show_all)
21 return 0;
22 result = result->next;
23 }
24
25 return 0;
26 }
27
28 static const char * const merge_base_usage[] = {
29 N_("git merge-base [-a | --all] <commit> <commit>..."),
30 N_("git merge-base [-a | --all] --octopus <commit>..."),
31 N_("git merge-base --independent <commit>..."),
32 N_("git merge-base --is-ancestor <commit> <commit>"),
33 N_("git merge-base --fork-point <ref> [<commit>]"),
34 NULL
35 };
36
37 static struct commit *get_commit_reference(const char *arg)
38 {
39 struct object_id revkey;
40 struct commit *r;
41
42 if (get_oid(arg, &revkey))
43 die("Not a valid object name %s", arg);
44 r = lookup_commit_reference(revkey.hash);
45 if (!r)
46 die("Not a valid commit name %s", arg);
47
48 return r;
49 }
50
51 static int handle_independent(int count, const char **args)
52 {
53 struct commit_list *revs = NULL;
54 struct commit_list *result;
55 int i;
56
57 for (i = count - 1; i >= 0; i--)
58 commit_list_insert(get_commit_reference(args[i]), &revs);
59
60 result = reduce_heads(revs);
61 if (!result)
62 return 1;
63
64 while (result) {
65 printf("%s\n", oid_to_hex(&result->item->object.oid));
66 result = result->next;
67 }
68 return 0;
69 }
70
71 static int handle_octopus(int count, const char **args, int show_all)
72 {
73 struct commit_list *revs = NULL;
74 struct commit_list *result;
75 int i;
76
77 for (i = count - 1; i >= 0; i--)
78 commit_list_insert(get_commit_reference(args[i]), &revs);
79
80 result = reduce_heads(get_octopus_merge_bases(revs));
81
82 if (!result)
83 return 1;
84
85 while (result) {
86 printf("%s\n", oid_to_hex(&result->item->object.oid));
87 if (!show_all)
88 return 0;
89 result = result->next;
90 }
91
92 return 0;
93 }
94
95 static int handle_is_ancestor(int argc, const char **argv)
96 {
97 struct commit *one, *two;
98
99 if (argc != 2)
100 die("--is-ancestor takes exactly two commits");
101 one = get_commit_reference(argv[0]);
102 two = get_commit_reference(argv[1]);
103 if (in_merge_bases(one, two))
104 return 0;
105 else
106 return 1;
107 }
108
109 struct rev_collect {
110 struct commit **commit;
111 int nr;
112 int alloc;
113 unsigned int initial : 1;
114 };
115
116 static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
117 {
118 struct commit *commit;
119
120 if (is_null_oid(oid))
121 return;
122
123 commit = lookup_commit(oid->hash);
124 if (!commit ||
125 (commit->object.flags & TMP_MARK) ||
126 parse_commit(commit))
127 return;
128
129 ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
130 revs->commit[revs->nr++] = commit;
131 commit->object.flags |= TMP_MARK;
132 }
133
134 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
135 const char *ident, unsigned long timestamp,
136 int tz, const char *message, void *cbdata)
137 {
138 struct rev_collect *revs = cbdata;
139
140 if (revs->initial) {
141 revs->initial = 0;
142 add_one_commit(ooid, revs);
143 }
144 add_one_commit(noid, revs);
145 return 0;
146 }
147
148 static int handle_fork_point(int argc, const char **argv)
149 {
150 struct object_id oid;
151 char *refname;
152 const char *commitname;
153 struct rev_collect revs;
154 struct commit *derived;
155 struct commit_list *bases;
156 int i, ret = 0;
157
158 switch (dwim_ref(argv[0], strlen(argv[0]), oid.hash, &refname)) {
159 case 0:
160 die("No such ref: '%s'", argv[0]);
161 case 1:
162 break; /* good */
163 default:
164 die("Ambiguous refname: '%s'", argv[0]);
165 }
166
167 commitname = (argc == 2) ? argv[1] : "HEAD";
168 if (get_oid(commitname, &oid))
169 die("Not a valid object name: '%s'", commitname);
170
171 derived = lookup_commit_reference(oid.hash);
172 memset(&revs, 0, sizeof(revs));
173 revs.initial = 1;
174 for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
175
176 if (!revs.nr && !get_oid(refname, &oid))
177 add_one_commit(&oid, &revs);
178
179 for (i = 0; i < revs.nr; i++)
180 revs.commit[i]->object.flags &= ~TMP_MARK;
181
182 bases = get_merge_bases_many_dirty(derived, revs.nr, revs.commit);
183
184 /*
185 * There should be one and only one merge base, when we found
186 * a common ancestor among reflog entries.
187 */
188 if (!bases || bases->next) {
189 ret = 1;
190 goto cleanup_return;
191 }
192
193 /* And the found one must be one of the reflog entries */
194 for (i = 0; i < revs.nr; i++)
195 if (&bases->item->object == &revs.commit[i]->object)
196 break; /* found */
197 if (revs.nr <= i) {
198 ret = 1; /* not found */
199 goto cleanup_return;
200 }
201
202 printf("%s\n", oid_to_hex(&bases->item->object.oid));
203
204 cleanup_return:
205 free_commit_list(bases);
206 return ret;
207 }
208
209 int cmd_merge_base(int argc, const char **argv, const char *prefix)
210 {
211 struct commit **rev;
212 int rev_nr = 0;
213 int show_all = 0;
214 int cmdmode = 0;
215
216 struct option options[] = {
217 OPT_BOOL('a', "all", &show_all, N_("output all common ancestors")),
218 OPT_CMDMODE(0, "octopus", &cmdmode,
219 N_("find ancestors for a single n-way merge"), 'o'),
220 OPT_CMDMODE(0, "independent", &cmdmode,
221 N_("list revs not reachable from others"), 'r'),
222 OPT_CMDMODE(0, "is-ancestor", &cmdmode,
223 N_("is the first one ancestor of the other?"), 'a'),
224 OPT_CMDMODE(0, "fork-point", &cmdmode,
225 N_("find where <commit> forked from reflog of <ref>"), 'f'),
226 OPT_END()
227 };
228
229 git_config(git_default_config, NULL);
230 argc = parse_options(argc, argv, prefix, options, merge_base_usage, 0);
231
232 if (cmdmode == 'a') {
233 if (argc < 2)
234 usage_with_options(merge_base_usage, options);
235 if (show_all)
236 die("--is-ancestor cannot be used with --all");
237 return handle_is_ancestor(argc, argv);
238 }
239
240 if (cmdmode == 'r' && show_all)
241 die("--independent cannot be used with --all");
242
243 if (cmdmode == 'o')
244 return handle_octopus(argc, argv, show_all);
245
246 if (cmdmode == 'r')
247 return handle_independent(argc, argv);
248
249 if (cmdmode == 'f') {
250 if (argc < 1 || 2 < argc)
251 usage_with_options(merge_base_usage, options);
252 return handle_fork_point(argc, argv);
253 }
254
255 if (argc < 2)
256 usage_with_options(merge_base_usage, options);
257
258 ALLOC_ARRAY(rev, argc);
259 while (argc-- > 0)
260 rev[rev_nr++] = get_commit_reference(*argv++);
261 return show_merge_base(rev, rev_nr, show_all);
262 }