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", sha1_to_hex(result->item->object.sha1));
  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         unsigned char revkey[20];
  40         struct commit *r;
  41
  42         if (get_sha1(arg, revkey))
  43                 die("Not a valid object name %s", arg);
  44         r = lookup_commit_reference(revkey);
  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", sha1_to_hex(result->item->object.sha1));
  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", sha1_to_hex(result->item->object.sha1));
  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(unsigned char *sha1, struct rev_collect *revs)
 117 {
 118         struct commit *commit;
 119
 120         if (is_null_sha1(sha1))
 121                 return;
 122
 123         commit = lookup_commit(sha1);
 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(unsigned char *osha1, unsigned char *nsha1,
 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(osha1, revs);
 143         }
 144         add_one_commit(nsha1, revs);
 145         return 0;
 146 }
 147
 148 static int handle_fork_point(int argc, const char **argv)
 149 {
 150         unsigned char sha1[20];
 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]), sha1, &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_sha1(commitname, sha1))
 169                 die("Not a valid object name: '%s'", commitname);
 170
 171         derived = lookup_commit_reference(sha1);
 172         memset(&revs, 0, sizeof(revs));
 173         revs.initial = 1;
 174         for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
 175
 176         for (i = 0; i < revs.nr; i++)
 177                 revs.commit[i]->object.flags &= ~TMP_MARK;
 178
 179         bases = get_merge_bases_many_dirty(derived, revs.nr, revs.commit);
 180
 181         /*
 182          * There should be one and only one merge base, when we found
 183          * a common ancestor among reflog entries.
 184          */
 185         if (!bases || bases->next) {
 186                 ret = 1;
 187                 goto cleanup_return;
 188         }
 189
 190         /* And the found one must be one of the reflog entries */
 191         for (i = 0; i < revs.nr; i++)
 192                 if (&bases->item->object == &revs.commit[i]->object)
 193                         break; /* found */
 194         if (revs.nr <= i) {
 195                 ret = 1; /* not found */
 196                 goto cleanup_return;
 197         }
 198
 199         printf("%s\n", sha1_to_hex(bases->item->object.sha1));
 200
 201 cleanup_return:
 202         free_commit_list(bases);
 203         return ret;
 204 }
 205
 206 int cmd_merge_base(int argc, const char **argv, const char *prefix)
 207 {
 208         struct commit **rev;
 209         int rev_nr = 0;
 210         int show_all = 0;
 211         int cmdmode = 0;
 212
 213         struct option options[] = {
 214                 OPT_BOOL('a', "all", &show_all, N_("output all common ancestors")),
 215                 OPT_CMDMODE(0, "octopus", &cmdmode,
 216                             N_("find ancestors for a single n-way merge"), 'o'),
 217                 OPT_CMDMODE(0, "independent", &cmdmode,
 218                             N_("list revs not reachable from others"), 'r'),
 219                 OPT_CMDMODE(0, "is-ancestor", &cmdmode,
 220                             N_("is the first one ancestor of the other?"), 'a'),
 221                 OPT_CMDMODE(0, "fork-point", &cmdmode,
 222                             N_("find where <commit> forked from reflog of <ref>"), 'f'),
 223                 OPT_END()
 224         };
 225
 226         git_config(git_default_config, NULL);
 227         argc = parse_options(argc, argv, prefix, options, merge_base_usage, 0);
 228
 229         if (cmdmode == 'a') {
 230                 if (argc < 2)
 231                         usage_with_options(merge_base_usage, options);
 232                 if (show_all)
 233                         die("--is-ancestor cannot be used with --all");
 234                 return handle_is_ancestor(argc, argv);
 235         }
 236
 237         if (cmdmode == 'r' && show_all)
 238                 die("--independent cannot be used with --all");
 239
 240         if (cmdmode == 'o')
 241                 return handle_octopus(argc, argv, show_all);
 242
 243         if (cmdmode == 'r')
 244                 return handle_independent(argc, argv);
 245
 246         if (cmdmode == 'f') {
 247                 if (argc < 1 || 2 < argc)
 248                         usage_with_options(merge_base_usage, options);
 249                 return handle_fork_point(argc, argv);
 250         }
 251
 252         if (argc < 2)
 253                 usage_with_options(merge_base_usage, options);
 254
 255         rev = xmalloc(argc * sizeof(*rev));
 256         while (argc-- > 0)
 257                 rev[rev_nr++] = get_commit_reference(*argv++);
 258         return show_merge_base(rev, rev_nr, show_all);
 259 }