builtin/merge-base.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "config.h"
   4 #include "commit.h"
   5 #include "refs.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "parse-options.h"
   9
  10 static int show_merge_base(struct commit **rev, int rev_nr, int show_all)
  11 {
  12         struct commit_list *result, *r;
  13
  14         result = get_merge_bases_many_dirty(rev[0], rev_nr - 1, rev + 1);
  15
  16         if (!result)
  17                 return 1;
  18
  19         for (r = result; r; r = r->next) {
  20                 printf("%s\n", oid_to_hex(&r->item->object.oid));
  21                 if (!show_all)
  22                         break;
  23         }
  24
  25         free_commit_list(result);
  26         return 0;
  27 }
  28
  29 static const char * const merge_base_usage[] = {
  30         N_("git merge-base [-a | --all] <commit> <commit>..."),
  31         N_("git merge-base [-a | --all] --octopus <commit>..."),
  32         N_("git merge-base --independent <commit>..."),
  33         N_("git merge-base --is-ancestor <commit> <commit>"),
  34         N_("git merge-base --fork-point <ref> [<commit>]"),
  35         NULL
  36 };
  37
  38 static struct commit *get_commit_reference(const char *arg)
  39 {
  40         struct object_id revkey;
  41         struct commit *r;
  42
  43         if (get_oid(arg, &revkey))
  44                 die("Not a valid object name %s", arg);
  45         r = lookup_commit_reference(&revkey);
  46         if (!r)
  47                 die("Not a valid commit name %s", arg);
  48
  49         return r;
  50 }
  51
  52 static int handle_independent(int count, const char **args)
  53 {
  54         struct commit_list *revs = NULL, *rev;
  55         int i;
  56
  57         for (i = count - 1; i >= 0; i--)
  58                 commit_list_insert(get_commit_reference(args[i]), &revs);
  59
  60         reduce_heads_replace(&revs);
  61
  62         if (!revs)
  63                 return 1;
  64
  65         for (rev = revs; rev; rev = rev->next)
  66                 printf("%s\n", oid_to_hex(&rev->item->object.oid));
  67
  68         free_commit_list(revs);
  69         return 0;
  70 }
  71
  72 static int handle_octopus(int count, const char **args, int show_all)
  73 {
  74         struct commit_list *revs = NULL;
  75         struct commit_list *result, *rev;
  76         int i;
  77
  78         for (i = count - 1; i >= 0; i--)
  79                 commit_list_insert(get_commit_reference(args[i]), &revs);
  80
  81         result = get_octopus_merge_bases(revs);
  82         free_commit_list(revs);
  83         reduce_heads_replace(&result);
  84
  85         if (!result)
  86                 return 1;
  87
  88         for (rev = result; rev; rev = rev->next) {
  89                 printf("%s\n", oid_to_hex(&rev->item->object.oid));
  90                 if (!show_all)
  91                         break;
  92         }
  93
  94         free_commit_list(result);
  95         return 0;
  96 }
  97
  98 static int handle_is_ancestor(int argc, const char **argv)
  99 {
 100         struct commit *one, *two;
 101
 102         if (argc != 2)
 103                 die("--is-ancestor takes exactly two commits");
 104         one = get_commit_reference(argv[0]);
 105         two = get_commit_reference(argv[1]);
 106         if (in_merge_bases(one, two))
 107                 return 0;
 108         else
 109                 return 1;
 110 }
 111
 112 struct rev_collect {
 113         struct commit **commit;
 114         int nr;
 115         int alloc;
 116         unsigned int initial : 1;
 117 };
 118
 119 static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 120 {
 121         struct commit *commit;
 122
 123         if (is_null_oid(oid))
 124                 return;
 125
 126         commit = lookup_commit(oid);
 127         if (!commit ||
 128             (commit->object.flags & TMP_MARK) ||
 129             parse_commit(commit))
 130                 return;
 131
 132         ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
 133         revs->commit[revs->nr++] = commit;
 134         commit->object.flags |= TMP_MARK;
 135 }
 136
 137 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 138                                   const char *ident, timestamp_t timestamp,
 139                                   int tz, const char *message, void *cbdata)
 140 {
 141         struct rev_collect *revs = cbdata;
 142
 143         if (revs->initial) {
 144                 revs->initial = 0;
 145                 add_one_commit(ooid, revs);
 146         }
 147         add_one_commit(noid, revs);
 148         return 0;
 149 }
 150
 151 static int handle_fork_point(int argc, const char **argv)
 152 {
 153         struct object_id oid;
 154         char *refname;
 155         const char *commitname;
 156         struct rev_collect revs;
 157         struct commit *derived;
 158         struct commit_list *bases;
 159         int i, ret = 0;
 160
 161         switch (dwim_ref(argv[0], strlen(argv[0]), &oid, &refname)) {
 162         case 0:
 163                 die("No such ref: '%s'", argv[0]);
 164         case 1:
 165                 break; /* good */
 166         default:
 167                 die("Ambiguous refname: '%s'", argv[0]);
 168         }
 169
 170         commitname = (argc == 2) ? argv[1] : "HEAD";
 171         if (get_oid(commitname, &oid))
 172                 die("Not a valid object name: '%s'", commitname);
 173
 174         derived = lookup_commit_reference(&oid);
 175         memset(&revs, 0, sizeof(revs));
 176         revs.initial = 1;
 177         for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
 178
 179         if (!revs.nr && !get_oid(refname, &oid))
 180                 add_one_commit(&oid, &revs);
 181
 182         for (i = 0; i < revs.nr; i++)
 183                 revs.commit[i]->object.flags &= ~TMP_MARK;
 184
 185         bases = get_merge_bases_many_dirty(derived, revs.nr, revs.commit);
 186
 187         /*
 188          * There should be one and only one merge base, when we found
 189          * a common ancestor among reflog entries.
 190          */
 191         if (!bases || bases->next) {
 192                 ret = 1;
 193                 goto cleanup_return;
 194         }
 195
 196         /* And the found one must be one of the reflog entries */
 197         for (i = 0; i < revs.nr; i++)
 198                 if (&bases->item->object == &revs.commit[i]->object)
 199                         break; /* found */
 200         if (revs.nr <= i) {
 201                 ret = 1; /* not found */
 202                 goto cleanup_return;
 203         }
 204
 205         printf("%s\n", oid_to_hex(&bases->item->object.oid));
 206
 207 cleanup_return:
 208         free_commit_list(bases);
 209         return ret;
 210 }
 211
 212 int cmd_merge_base(int argc, const char **argv, const char *prefix)
 213 {
 214         struct commit **rev;
 215         int rev_nr = 0;
 216         int show_all = 0;
 217         int cmdmode = 0;
 218
 219         struct option options[] = {
 220                 OPT_BOOL('a', "all", &show_all, N_("output all common ancestors")),
 221                 OPT_CMDMODE(0, "octopus", &cmdmode,
 222                             N_("find ancestors for a single n-way merge"), 'o'),
 223                 OPT_CMDMODE(0, "independent", &cmdmode,
 224                             N_("list revs not reachable from others"), 'r'),
 225                 OPT_CMDMODE(0, "is-ancestor", &cmdmode,
 226                             N_("is the first one ancestor of the other?"), 'a'),
 227                 OPT_CMDMODE(0, "fork-point", &cmdmode,
 228                             N_("find where <commit> forked from reflog of <ref>"), 'f'),
 229                 OPT_END()
 230         };
 231
 232         git_config(git_default_config, NULL);
 233         argc = parse_options(argc, argv, prefix, options, merge_base_usage, 0);
 234
 235         if (cmdmode == 'a') {
 236                 if (argc < 2)
 237                         usage_with_options(merge_base_usage, options);
 238                 if (show_all)
 239                         die("--is-ancestor cannot be used with --all");
 240                 return handle_is_ancestor(argc, argv);
 241         }
 242
 243         if (cmdmode == 'r' && show_all)
 244                 die("--independent cannot be used with --all");
 245
 246         if (cmdmode == 'o')
 247                 return handle_octopus(argc, argv, show_all);
 248
 249         if (cmdmode == 'r')
 250                 return handle_independent(argc, argv);
 251
 252         if (cmdmode == 'f') {
 253                 if (argc < 1 || 2 < argc)
 254                         usage_with_options(merge_base_usage, options);
 255                 return handle_fork_point(argc, argv);
 256         }
 257
 258         if (argc < 2)
 259                 usage_with_options(merge_base_usage, options);
 260
 261         ALLOC_ARRAY(rev, argc);
 262         while (argc-- > 0)
 263                 rev[rev_nr++] = get_commit_reference(*argv++);
 264         return show_merge_base(rev, rev_nr, show_all);
 265 }