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 #include "repository.h"
  10
  11 static int show_merge_base(struct commit **rev, int rev_nr, int show_all)
  12 {
  13         struct commit_list *result, *r;
  14
  15         result = get_merge_bases_many_dirty(rev[0], rev_nr - 1, rev + 1);
  16
  17         if (!result)
  18                 return 1;
  19
  20         for (r = result; r; r = r->next) {
  21                 printf("%s\n", oid_to_hex(&r->item->object.oid));
  22                 if (!show_all)
  23                         break;
  24         }
  25
  26         free_commit_list(result);
  27         return 0;
  28 }
  29
  30 static const char * const merge_base_usage[] = {
  31         N_("git merge-base [-a | --all] <commit> <commit>..."),
  32         N_("git merge-base [-a | --all] --octopus <commit>..."),
  33         N_("git merge-base --independent <commit>..."),
  34         N_("git merge-base --is-ancestor <commit> <commit>"),
  35         N_("git merge-base --fork-point <ref> [<commit>]"),
  36         NULL
  37 };
  38
  39 static struct commit *get_commit_reference(const char *arg)
  40 {
  41         struct object_id revkey;
  42         struct commit *r;
  43
  44         if (get_oid(arg, &revkey))
  45                 die("Not a valid object name %s", arg);
  46         r = lookup_commit_reference(the_repository, &revkey);
  47         if (!r)
  48                 die("Not a valid commit name %s", arg);
  49
  50         return r;
  51 }
  52
  53 static int handle_independent(int count, const char **args)
  54 {
  55         struct commit_list *revs = NULL, *rev;
  56         int i;
  57
  58         for (i = count - 1; i >= 0; i--)
  59                 commit_list_insert(get_commit_reference(args[i]), &revs);
  60
  61         reduce_heads_replace(&revs);
  62
  63         if (!revs)
  64                 return 1;
  65
  66         for (rev = revs; rev; rev = rev->next)
  67                 printf("%s\n", oid_to_hex(&rev->item->object.oid));
  68
  69         free_commit_list(revs);
  70         return 0;
  71 }
  72
  73 static int handle_octopus(int count, const char **args, int show_all)
  74 {
  75         struct commit_list *revs = NULL;
  76         struct commit_list *result, *rev;
  77         int i;
  78
  79         for (i = count - 1; i >= 0; i--)
  80                 commit_list_insert(get_commit_reference(args[i]), &revs);
  81
  82         result = get_octopus_merge_bases(revs);
  83         free_commit_list(revs);
  84         reduce_heads_replace(&result);
  85
  86         if (!result)
  87                 return 1;
  88
  89         for (rev = result; rev; rev = rev->next) {
  90                 printf("%s\n", oid_to_hex(&rev->item->object.oid));
  91                 if (!show_all)
  92                         break;
  93         }
  94
  95         free_commit_list(result);
  96         return 0;
  97 }
  98
  99 static int handle_is_ancestor(int argc, const char **argv)
 100 {
 101         struct commit *one, *two;
 102
 103         if (argc != 2)
 104                 die("--is-ancestor takes exactly two commits");
 105         one = get_commit_reference(argv[0]);
 106         two = get_commit_reference(argv[1]);
 107         if (in_merge_bases(one, two))
 108                 return 0;
 109         else
 110                 return 1;
 111 }
 112
 113 struct rev_collect {
 114         struct commit **commit;
 115         int nr;
 116         int alloc;
 117         unsigned int initial : 1;
 118 };
 119
 120 static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 121 {
 122         struct commit *commit;
 123
 124         if (is_null_oid(oid))
 125                 return;
 126
 127         commit = lookup_commit(the_repository, oid);
 128         if (!commit ||
 129             (commit->object.flags & TMP_MARK) ||
 130             parse_commit(commit))
 131                 return;
 132
 133         ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
 134         revs->commit[revs->nr++] = commit;
 135         commit->object.flags |= TMP_MARK;
 136 }
 137
 138 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 139                                   const char *ident, timestamp_t timestamp,
 140                                   int tz, const char *message, void *cbdata)
 141 {
 142         struct rev_collect *revs = cbdata;
 143
 144         if (revs->initial) {
 145                 revs->initial = 0;
 146                 add_one_commit(ooid, revs);
 147         }
 148         add_one_commit(noid, revs);
 149         return 0;
 150 }
 151
 152 static int handle_fork_point(int argc, const char **argv)
 153 {
 154         struct object_id oid;
 155         char *refname;
 156         const char *commitname;
 157         struct rev_collect revs;
 158         struct commit *derived;
 159         struct commit_list *bases;
 160         int i, ret = 0;
 161
 162         switch (dwim_ref(argv[0], strlen(argv[0]), &oid, &refname)) {
 163         case 0:
 164                 die("No such ref: '%s'", argv[0]);
 165         case 1:
 166                 break; /* good */
 167         default:
 168                 die("Ambiguous refname: '%s'", argv[0]);
 169         }
 170
 171         commitname = (argc == 2) ? argv[1] : "HEAD";
 172         if (get_oid(commitname, &oid))
 173                 die("Not a valid object name: '%s'", commitname);
 174
 175         derived = lookup_commit_reference(the_repository, &oid);
 176         memset(&revs, 0, sizeof(revs));
 177         revs.initial = 1;
 178         for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
 179
 180         if (!revs.nr && !get_oid(refname, &oid))
 181                 add_one_commit(&oid, &revs);
 182
 183         for (i = 0; i < revs.nr; i++)
 184                 revs.commit[i]->object.flags &= ~TMP_MARK;
 185
 186         bases = get_merge_bases_many_dirty(derived, revs.nr, revs.commit);
 187
 188         /*
 189          * There should be one and only one merge base, when we found
 190          * a common ancestor among reflog entries.
 191          */
 192         if (!bases || bases->next) {
 193                 ret = 1;
 194                 goto cleanup_return;
 195         }
 196
 197         /* And the found one must be one of the reflog entries */
 198         for (i = 0; i < revs.nr; i++)
 199                 if (&bases->item->object == &revs.commit[i]->object)
 200                         break; /* found */
 201         if (revs.nr <= i) {
 202                 ret = 1; /* not found */
 203                 goto cleanup_return;
 204         }
 205
 206         printf("%s\n", oid_to_hex(&bases->item->object.oid));
 207
 208 cleanup_return:
 209         free_commit_list(bases);
 210         return ret;
 211 }
 212
 213 int cmd_merge_base(int argc, const char **argv, const char *prefix)
 214 {
 215         struct commit **rev;
 216         int rev_nr = 0;
 217         int show_all = 0;
 218         int cmdmode = 0;
 219
 220         struct option options[] = {
 221                 OPT_BOOL('a', "all", &show_all, N_("output all common ancestors")),
 222                 OPT_CMDMODE(0, "octopus", &cmdmode,
 223                             N_("find ancestors for a single n-way merge"), 'o'),
 224                 OPT_CMDMODE(0, "independent", &cmdmode,
 225                             N_("list revs not reachable from others"), 'r'),
 226                 OPT_CMDMODE(0, "is-ancestor", &cmdmode,
 227                             N_("is the first one ancestor of the other?"), 'a'),
 228                 OPT_CMDMODE(0, "fork-point", &cmdmode,
 229                             N_("find where <commit> forked from reflog of <ref>"), 'f'),
 230                 OPT_END()
 231         };
 232
 233         git_config(git_default_config, NULL);
 234         argc = parse_options(argc, argv, prefix, options, merge_base_usage, 0);
 235
 236         if (cmdmode == 'a') {
 237                 if (argc < 2)
 238                         usage_with_options(merge_base_usage, options);
 239                 if (show_all)
 240                         die("--is-ancestor cannot be used with --all");
 241                 return handle_is_ancestor(argc, argv);
 242         }
 243
 244         if (cmdmode == 'r' && show_all)
 245                 die("--independent cannot be used with --all");
 246
 247         if (cmdmode == 'o')
 248                 return handle_octopus(argc, argv, show_all);
 249
 250         if (cmdmode == 'r')
 251                 return handle_independent(argc, argv);
 252
 253         if (cmdmode == 'f') {
 254                 if (argc < 1 || 2 < argc)
 255                         usage_with_options(merge_base_usage, options);
 256                 return handle_fork_point(argc, argv);
 257         }
 258
 259         if (argc < 2)
 260                 usage_with_options(merge_base_usage, options);
 261
 262         ALLOC_ARRAY(rev, argc);
 263         while (argc-- > 0)
 264                 rev[rev_nr++] = get_commit_reference(*argv++);
 265         return show_merge_base(rev, rev_nr, show_all);
 266 }