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         const char *shortname = remote + 11;
  53         int remote_is_branch = !prefixcmp(remote, "refs/heads/");
  54         struct strbuf key = STRBUF_INIT;
  55         int rebasing = should_setup_rebase(origin);
  56
  57         if (remote_is_branch
  58             && !strcmp(local, shortname)
  59             && !origin) {
  60                 warning("Not setting branch %s as its own upstream.",
  61                         local);
  62                 return;
  63         }
  64
  65         strbuf_addf(&key, "branch.%s.remote", local);
  66         git_config_set(key.buf, origin ? origin : ".");
  67
  68         strbuf_reset(&key);
  69         strbuf_addf(&key, "branch.%s.merge", local);
  70         git_config_set(key.buf, remote);
  71
  72         if (rebasing) {
  73                 strbuf_reset(&key);
  74                 strbuf_addf(&key, "branch.%s.rebase", local);
  75                 git_config_set(key.buf, "true");
  76         }
  77
  78         if (flag & BRANCH_CONFIG_VERBOSE) {
  79                 strbuf_reset(&key);
  80
  81                 strbuf_addstr(&key, origin ? "remote" : "local");
  82
  83                 /* Are we tracking a proper "branch"? */
  84                 if (remote_is_branch) {
  85                         strbuf_addf(&key, " branch %s", shortname);
  86                         if (origin)
  87                                 strbuf_addf(&key, " from %s", origin);
  88                 }
  89                 else
  90                         strbuf_addf(&key, " ref %s", remote);
  91                 printf("Branch %s set up to track %s%s.\n",
  92                        local, key.buf,
  93                        rebasing ? " by rebasing" : "");
  94         }
  95         strbuf_release(&key);
  96 }
  97
  98 /*
  99  * This is called when new_ref is branched off of orig_ref, and tries
 100  * to infer the settings for branch.<new_ref>.{remote,merge} from the
 101  * config.
 102  */
 103 static int setup_tracking(const char *new_ref, const char *orig_ref,
 104                           enum branch_track track)
 105 {
 106         struct tracking tracking;
 107
 108         if (strlen(new_ref) > 1024 - 7 - 7 - 1)
 109                 return error("Tracking not set up: name too long: %s",
 110                                 new_ref);
 111
 112         memset(&tracking, 0, sizeof(tracking));
 113         tracking.spec.dst = (char *)orig_ref;
 114         if (for_each_remote(find_tracked_branch, &tracking))
 115                 return 1;
 116
 117         if (!tracking.matches)
 118                 switch (track) {
 119                 case BRANCH_TRACK_ALWAYS:
 120                 case BRANCH_TRACK_EXPLICIT:
 121                 case BRANCH_TRACK_OVERRIDE:
 122                         break;
 123                 default:
 124                         return 1;
 125                 }
 126
 127         if (tracking.matches > 1)
 128                 return error("Not tracking: ambiguous information for ref %s",
 129                                 orig_ref);
 130
 131         install_branch_config(BRANCH_CONFIG_VERBOSE, new_ref, tracking.remote,
 132                               tracking.src ? tracking.src : orig_ref);
 133
 134         free(tracking.src);
 135         return 0;
 136 }
 137
 138 int validate_new_branchname(const char *name, struct strbuf *ref, int force)
 139 {
 140         const char *head;
 141         unsigned char sha1[20];
 142
 143         if (strbuf_check_branch_ref(ref, name))
 144                 die("'%s' is not a valid branch name.", name);
 145
 146         if (!ref_exists(ref->buf))
 147                 return 0;
 148         else if (!force)
 149                 die("A branch named '%s' already exists.", ref->buf + strlen("refs/heads/"));
 150
 151         head = resolve_ref("HEAD", sha1, 0, NULL);
 152         if (!is_bare_repository() && head && !strcmp(head, ref->buf))
 153                 die("Cannot force update the current branch.");
 154
 155         return 1;
 156 }
 157
 158 void create_branch(const char *head,
 159                    const char *name, const char *start_name,
 160                    int force, int reflog, enum branch_track track)
 161 {
 162         struct ref_lock *lock = NULL;
 163         struct commit *commit;
 164         unsigned char sha1[20];
 165         char *real_ref, msg[PATH_MAX + 20];
 166         struct strbuf ref = STRBUF_INIT;
 167         int forcing = 0;
 168         int dont_change_ref = 0;
 169         int explicit_tracking = 0;
 170
 171         if (track == BRANCH_TRACK_EXPLICIT || track == BRANCH_TRACK_OVERRIDE)
 172                 explicit_tracking = 1;
 173
 174         if (validate_new_branchname(name, &ref, force || track == BRANCH_TRACK_OVERRIDE)) {
 175                 if (!force)
 176                         dont_change_ref = 1;
 177                 else
 178                         forcing = 1;
 179         }
 180
 181         real_ref = NULL;
 182         if (get_sha1(start_name, sha1))
 183                 die("Not a valid object name: '%s'.", start_name);
 184
 185         switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
 186         case 0:
 187                 /* Not branching from any existing branch */
 188                 if (explicit_tracking)
 189                         die("Cannot setup tracking information; starting point is not a branch.");
 190                 break;
 191         case 1:
 192                 /* Unique completion -- good, only if it is a real branch */
 193                 if (prefixcmp(real_ref, "refs/heads/") &&
 194                     prefixcmp(real_ref, "refs/remotes/")) {
 195                         if (explicit_tracking)
 196                                 die("Cannot setup tracking information; starting point is not a branch.");
 197                         else
 198                                 real_ref = NULL;
 199                 }
 200                 break;
 201         default:
 202                 die("Ambiguous object name: '%s'.", start_name);
 203                 break;
 204         }
 205
 206         if ((commit = lookup_commit_reference(sha1)) == NULL)
 207                 die("Not a valid branch point: '%s'.", start_name);
 208         hashcpy(sha1, commit->object.sha1);
 209
 210         if (!dont_change_ref) {
 211                 lock = lock_any_ref_for_update(ref.buf, NULL, 0);
 212                 if (!lock)
 213                         die_errno("Failed to lock ref for update");
 214         }
 215
 216         if (reflog)
 217                 log_all_ref_updates = 1;
 218
 219         if (forcing)
 220                 snprintf(msg, sizeof msg, "branch: Reset to %s",
 221                          start_name);
 222         else if (!dont_change_ref)
 223                 snprintf(msg, sizeof msg, "branch: Created from %s",
 224                          start_name);
 225
 226         if (real_ref && track)
 227                 setup_tracking(ref.buf+11, real_ref, track);
 228
 229         if (!dont_change_ref)
 230                 if (write_ref_sha1(lock, sha1, msg) < 0)
 231                         die_errno("Failed to write ref");
 232
 233         strbuf_release(&ref);
 234         free(real_ref);
 235 }
 236
 237 void remove_branch_state(void)
 238 {
 239         unlink(git_path("CHERRY_PICK_HEAD"));
 240         unlink(git_path("MERGE_HEAD"));
 241         unlink(git_path("MERGE_RR"));
 242         unlink(git_path("MERGE_MSG"));
 243         unlink(git_path("MERGE_MODE"));
 244         unlink(git_path("SQUASH_MSG"));
 245 }