branch.c

   1 #include "cache.h"
   2 #include "branch.h"
   3 #include "refs.h"
   4 #include "remote.h"
   5 #include "commit.h"
   6
   7 struct tracking {
   8         struct refspec spec;
   9         char *src;
  10         const char *remote;
  11         int matches;
  12 };
  13
  14 static int find_tracked_branch(struct remote *remote, void *priv)
  15 {
  16         struct tracking *tracking = priv;
  17
  18         if (!remote_find_tracking(remote, &tracking->spec)) {
  19                 if (++tracking->matches == 1) {
  20                         tracking->src = tracking->spec.src;
  21                         tracking->remote = remote->name;
  22                 } else {
  23                         free(tracking->spec.src);
  24                         if (tracking->src) {
  25                                 free(tracking->src);
  26                                 tracking->src = NULL;
  27                         }
  28                 }
  29                 tracking->spec.src = NULL;
  30         }
  31
  32         return 0;
  33 }
  34
  35 static int should_setup_rebase(const char *origin)
  36 {
  37         switch (autorebase) {
  38         case AUTOREBASE_NEVER:
  39                 return 0;
  40         case AUTOREBASE_LOCAL:
  41                 return origin == NULL;
  42         case AUTOREBASE_REMOTE:
  43                 return origin != NULL;
  44         case AUTOREBASE_ALWAYS:
  45                 return 1;
  46         }
  47         return 0;
  48 }
  49
  50 void install_branch_config(int flag, const char *local, const char *origin, const char *remote)
  51 {
  52         struct strbuf key = STRBUF_INIT;
  53         int rebasing = should_setup_rebase(origin);
  54
  55         strbuf_addf(&key, "branch.%s.remote", local);
  56         git_config_set(key.buf, origin ? origin : ".");
  57
  58         strbuf_reset(&key);
  59         strbuf_addf(&key, "branch.%s.merge", local);
  60         git_config_set(key.buf, remote);
  61
  62         if (rebasing) {
  63                 strbuf_reset(&key);
  64                 strbuf_addf(&key, "branch.%s.rebase", local);
  65                 git_config_set(key.buf, "true");
  66         }
  67
  68         if (flag & BRANCH_CONFIG_VERBOSE) {
  69                 strbuf_reset(&key);
  70
  71                 strbuf_addstr(&key, origin ? "remote" : "local");
  72
  73                 /* Are we tracking a proper "branch"? */
  74                 if (!prefixcmp(remote, "refs/heads/")) {
  75                         strbuf_addf(&key, " branch %s", remote + 11);
  76                         if (origin)
  77                                 strbuf_addf(&key, " from %s", origin);
  78                 }
  79                 else
  80                         strbuf_addf(&key, " ref %s", remote);
  81                 printf("Branch %s set up to track %s%s.\n",
  82                        local, key.buf,
  83                        rebasing ? " by rebasing" : "");
  84         }
  85         strbuf_release(&key);
  86 }
  87
  88 /*
  89  * This is called when new_ref is branched off of orig_ref, and tries
  90  * to infer the settings for branch.<new_ref>.{remote,merge} from the
  91  * config.
  92  */
  93 static int setup_tracking(const char *new_ref, const char *orig_ref,
  94                           enum branch_track track)
  95 {
  96         struct tracking tracking;
  97
  98         if (strlen(new_ref) > 1024 - 7 - 7 - 1)
  99                 return error("Tracking not set up: name too long: %s",
 100                                 new_ref);
 101
 102         memset(&tracking, 0, sizeof(tracking));
 103         tracking.spec.dst = (char *)orig_ref;
 104         if (for_each_remote(find_tracked_branch, &tracking))
 105                 return 1;
 106
 107         if (!tracking.matches)
 108                 switch (track) {
 109                 case BRANCH_TRACK_ALWAYS:
 110                 case BRANCH_TRACK_EXPLICIT:
 111                         break;
 112                 default:
 113                         return 1;
 114                 }
 115
 116         if (tracking.matches > 1)
 117                 return error("Not tracking: ambiguous information for ref %s",
 118                                 orig_ref);
 119
 120         install_branch_config(BRANCH_CONFIG_VERBOSE, new_ref, tracking.remote,
 121                               tracking.src ? tracking.src : orig_ref);
 122
 123         free(tracking.src);
 124         return 0;
 125 }
 126
 127 void create_branch(const char *head,
 128                    const char *name, const char *start_name,
 129                    int force, int reflog, enum branch_track track)
 130 {
 131         struct ref_lock *lock;
 132         struct commit *commit;
 133         unsigned char sha1[20];
 134         char *real_ref, msg[PATH_MAX + 20];
 135         struct strbuf ref = STRBUF_INIT;
 136         int forcing = 0;
 137         int len;
 138
 139         len = strlen(name);
 140         if (interpret_nth_last_branch(name, &ref) != len) {
 141                 strbuf_reset(&ref);
 142                 strbuf_add(&ref, name, len);
 143         }
 144         strbuf_splice(&ref, 0, 0, "refs/heads/", 11);
 145
 146         if (check_ref_format(ref.buf))
 147                 die("'%s' is not a valid branch name.", name);
 148
 149         if (resolve_ref(ref.buf, sha1, 1, NULL)) {
 150                 if (!force)
 151                         die("A branch named '%s' already exists.", name);
 152                 else if (!is_bare_repository() && !strcmp(head, name))
 153                         die("Cannot force update the current branch.");
 154                 forcing = 1;
 155         }
 156
 157         real_ref = NULL;
 158         if (get_sha1(start_name, sha1))
 159                 die("Not a valid object name: '%s'.", start_name);
 160
 161         switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
 162         case 0:
 163                 /* Not branching from any existing branch */
 164                 if (track == BRANCH_TRACK_EXPLICIT)
 165                         die("Cannot setup tracking information; starting point is not a branch.");
 166                 break;
 167         case 1:
 168                 /* Unique completion -- good, only if it is a real ref */
 169                 if (track == BRANCH_TRACK_EXPLICIT && !strcmp(real_ref, "HEAD"))
 170                         die("Cannot setup tracking information; starting point is not a branch.");
 171                 break;
 172         default:
 173                 die("Ambiguous object name: '%s'.", start_name);
 174                 break;
 175         }
 176
 177         if ((commit = lookup_commit_reference(sha1)) == NULL)
 178                 die("Not a valid branch point: '%s'.", start_name);
 179         hashcpy(sha1, commit->object.sha1);
 180
 181         lock = lock_any_ref_for_update(ref.buf, NULL, 0);
 182         if (!lock)
 183                 die("Failed to lock ref for update: %s.", strerror(errno));
 184
 185         if (reflog)
 186                 log_all_ref_updates = 1;
 187
 188         if (forcing)
 189                 snprintf(msg, sizeof msg, "branch: Reset from %s",
 190                          start_name);
 191         else
 192                 snprintf(msg, sizeof msg, "branch: Created from %s",
 193                          start_name);
 194
 195         if (real_ref && track)
 196                 setup_tracking(name, real_ref, track);
 197
 198         if (write_ref_sha1(lock, sha1, msg) < 0)
 199                 die("Failed to write ref: %s.", strerror(errno));
 200
 201         strbuf_release(&ref);
 202         free(real_ref);
 203 }
 204
 205 void remove_branch_state(void)
 206 {
 207         unlink(git_path("MERGE_HEAD"));
 208         unlink(git_path("MERGE_RR"));
 209         unlink(git_path("MERGE_MSG"));
 210         unlink(git_path("MERGE_MODE"));
 211         unlink(git_path("SQUASH_MSG"));
 212 }