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 #include "commit-reach.h"
  11
  12 static int show_merge_base(struct commit **rev, int rev_nr, int show_all)
  13 {
  14         struct commit_list *result, *r;
  15
  16         result = get_merge_bases_many_dirty(rev[0], rev_nr - 1, rev + 1);
  17
  18         if (!result)
  19                 return 1;
  20
  21         for (r = result; r; r = r->next) {
  22                 printf("%s\n", oid_to_hex(&r->item->object.oid));
  23                 if (!show_all)
  24                         break;
  25         }
  26
  27         free_commit_list(result);
  28         return 0;
  29 }
  30
  31 static const char * const merge_base_usage[] = {
  32         N_("git merge-base [-a | --all] <commit> <commit>..."),
  33         N_("git merge-base [-a | --all] --octopus <commit>..."),
  34         N_("git merge-base --independent <commit>..."),
  35         N_("git merge-base --is-ancestor <commit> <commit>"),
  36         N_("git merge-base --fork-point <ref> [<commit>]"),
  37         NULL
  38 };
  39
  40 static struct commit *get_commit_reference(const char *arg)
  41 {
  42         struct object_id revkey;
  43         struct commit *r;
  44
  45         if (get_oid(arg, &revkey))
  46                 die("Not a valid object name %s", arg);
  47         r = lookup_commit_reference(the_repository, &revkey);
  48         if (!r)
  49                 die("Not a valid commit name %s", arg);
  50
  51         return r;
  52 }
  53
  54 static int handle_independent(int count, const char **args)
  55 {
  56         struct commit_list *revs = NULL, *rev;
  57         int i;
  58
  59         for (i = count - 1; i >= 0; i--)
  60                 commit_list_insert(get_commit_reference(args[i]), &revs);
  61
  62         reduce_heads_replace(&revs);
  63
  64         if (!revs)
  65                 return 1;
  66
  67         for (rev = revs; rev; rev = rev->next)
  68                 printf("%s\n", oid_to_hex(&rev->item->object.oid));
  69
  70         free_commit_list(revs);
  71         return 0;
  72 }
  73
  74 static int handle_octopus(int count, const char **args, int show_all)
  75 {
  76         struct commit_list *revs = NULL;
  77         struct commit_list *result, *rev;
  78         int i;
  79
  80         for (i = count - 1; i >= 0; i--)
  81                 commit_list_insert(get_commit_reference(args[i]), &revs);
  82
  83         result = get_octopus_merge_bases(revs);
  84         free_commit_list(revs);
  85         reduce_heads_replace(&result);
  86
  87         if (!result)
  88                 return 1;
  89
  90         for (rev = result; rev; rev = rev->next) {
  91                 printf("%s\n", oid_to_hex(&rev->item->object.oid));
  92                 if (!show_all)
  93                         break;
  94         }
  95
  96         free_commit_list(result);
  97         return 0;
  98 }
  99
 100 static int handle_is_ancestor(int argc, const char **argv)
 101 {
 102         struct commit *one, *two;
 103
 104         if (argc != 2)
 105                 die("--is-ancestor takes exactly two commits");
 106         one = get_commit_reference(argv[0]);
 107         two = get_commit_reference(argv[1]);
 108         if (in_merge_bases(one, two))
 109                 return 0;
 110         else
 111                 return 1;
 112 }
 113
 114 struct rev_collect {
 115         struct commit **commit;
 116         int nr;
 117         int alloc;
 118         unsigned int initial : 1;
 119 };
 120
 121 static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 122 {
 123         struct commit *commit;
 124
 125         if (is_null_oid(oid))
 126                 return;
 127
 128         commit = lookup_commit(the_repository, oid);
 129         if (!commit ||
 130             (commit->object.flags & TMP_MARK) ||
 131             parse_commit(commit))
 132                 return;
 133
 134         ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
 135         revs->commit[revs->nr++] = commit;
 136         commit->object.flags |= TMP_MARK;
 137 }
 138
 139 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 140                                   const char *ident, timestamp_t timestamp,
 141                                   int tz, const char *message, void *cbdata)
 142 {
 143         struct rev_collect *revs = cbdata;
 144
 145         if (revs->initial) {
 146                 revs->initial = 0;
 147                 add_one_commit(ooid, revs);
 148         }
 149         add_one_commit(noid, revs);
 150         return 0;
 151 }
 152
 153 static int handle_fork_point(int argc, const char **argv)
 154 {
 155         struct object_id oid;
 156         char *refname;
 157         const char *commitname;
 158         struct rev_collect revs;
 159         struct commit *derived;
 160         struct commit_list *bases;
 161         int i, ret = 0;
 162
 163         switch (dwim_ref(argv[0], strlen(argv[0]), &oid, &refname)) {
 164         case 0:
 165                 die("No such ref: '%s'", argv[0]);
 166         case 1:
 167                 break; /* good */
 168         default:
 169                 die("Ambiguous refname: '%s'", argv[0]);
 170         }
 171
 172         commitname = (argc == 2) ? argv[1] : "HEAD";
 173         if (get_oid(commitname, &oid))
 174                 die("Not a valid object name: '%s'", commitname);
 175
 176         derived = lookup_commit_reference(the_repository, &oid);
 177         memset(&revs, 0, sizeof(revs));
 178         revs.initial = 1;
 179         for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
 180
 181         if (!revs.nr && !get_oid(refname, &oid))
 182                 add_one_commit(&oid, &revs);
 183
 184         for (i = 0; i < revs.nr; i++)
 185                 revs.commit[i]->object.flags &= ~TMP_MARK;
 186
 187         bases = get_merge_bases_many_dirty(derived, revs.nr, revs.commit);
 188
 189         /*
 190          * There should be one and only one merge base, when we found
 191          * a common ancestor among reflog entries.
 192          */
 193         if (!bases || bases->next) {
 194                 ret = 1;
 195                 goto cleanup_return;
 196         }
 197
 198         /* And the found one must be one of the reflog entries */
 199         for (i = 0; i < revs.nr; i++)
 200                 if (&bases->item->object == &revs.commit[i]->object)
 201                         break; /* found */
 202         if (revs.nr <= i) {
 203                 ret = 1; /* not found */
 204                 goto cleanup_return;
 205         }
 206
 207         printf("%s\n", oid_to_hex(&bases->item->object.oid));
 208
 209 cleanup_return:
 210         free_commit_list(bases);
 211         return ret;
 212 }
 213
 214 int cmd_merge_base(int argc, const char **argv, const char *prefix)
 215 {
 216         struct commit **rev;
 217         int rev_nr = 0;
 218         int show_all = 0;
 219         int cmdmode = 0;
 220
 221         struct option options[] = {
 222                 OPT_BOOL('a', "all", &show_all, N_("output all common ancestors")),
 223                 OPT_CMDMODE(0, "octopus", &cmdmode,
 224                             N_("find ancestors for a single n-way merge"), 'o'),
 225                 OPT_CMDMODE(0, "independent", &cmdmode,
 226                             N_("list revs not reachable from others"), 'r'),
 227                 OPT_CMDMODE(0, "is-ancestor", &cmdmode,
 228                             N_("is the first one ancestor of the other?"), 'a'),
 229                 OPT_CMDMODE(0, "fork-point", &cmdmode,
 230                             N_("find where <commit> forked from reflog of <ref>"), 'f'),
 231                 OPT_END()
 232         };
 233
 234         git_config(git_default_config, NULL);
 235         argc = parse_options(argc, argv, prefix, options, merge_base_usage, 0);
 236
 237         if (cmdmode == 'a') {
 238                 if (argc < 2)
 239                         usage_with_options(merge_base_usage, options);
 240                 if (show_all)
 241                         die("--is-ancestor cannot be used with --all");
 242                 return handle_is_ancestor(argc, argv);
 243         }
 244
 245         if (cmdmode == 'r' && show_all)
 246                 die("--independent cannot be used with --all");
 247
 248         if (cmdmode == 'o')
 249                 return handle_octopus(argc, argv, show_all);
 250
 251         if (cmdmode == 'r')
 252                 return handle_independent(argc, argv);
 253
 254         if (cmdmode == 'f') {
 255                 if (argc < 1 || 2 < argc)
 256                         usage_with_options(merge_base_usage, options);
 257                 return handle_fork_point(argc, argv);
 258         }
 259
 260         if (argc < 2)
 261                 usage_with_options(merge_base_usage, options);
 262
 263         ALLOC_ARRAY(rev, argc);
 264         while (argc-- > 0)
 265                 rev[rev_nr++] = get_commit_reference(*argv++);
 266         return show_merge_base(rev, rev_nr, show_all);
 267 }