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 /*
  36  * This is called when new_ref is branched off of orig_ref, and tries
  37  * to infer the settings for branch.<new_ref>.{remote,merge} from the
  38  * config.
  39  */
  40 static int setup_tracking(const char *new_ref, const char *orig_ref,
  41                           enum branch_track track)
  42 {
  43         char key[1024];
  44         struct tracking tracking;
  45
  46         if (strlen(new_ref) > 1024 - 7 - 7 - 1)
  47                 return error("Tracking not set up: name too long: %s",
  48                                 new_ref);
  49
  50         memset(&tracking, 0, sizeof(tracking));
  51         tracking.spec.dst = (char *)orig_ref;
  52         if (for_each_remote(find_tracked_branch, &tracking))
  53                 return 1;
  54
  55         if (!tracking.matches)
  56                 switch (track) {
  57                 case BRANCH_TRACK_ALWAYS:
  58                 case BRANCH_TRACK_EXPLICIT:
  59                         break;
  60                 default:
  61                         return 1;
  62                 }
  63
  64         if (tracking.matches > 1)
  65                 return error("Not tracking: ambiguous information for ref %s",
  66                                 orig_ref);
  67
  68         sprintf(key, "branch.%s.remote", new_ref);
  69         git_config_set(key, tracking.remote ?  tracking.remote : ".");
  70         sprintf(key, "branch.%s.merge", new_ref);
  71         git_config_set(key, tracking.src ? tracking.src : orig_ref);
  72         free(tracking.src);
  73         printf("Branch %s set up to track %s branch %s.\n", new_ref,
  74                 tracking.remote ? "remote" : "local", orig_ref);
  75
  76         return 0;
  77 }
  78
  79 void create_branch(const char *head,
  80                    const char *name, const char *start_name,
  81                    int force, int reflog, enum branch_track track)
  82 {
  83         struct ref_lock *lock;
  84         struct commit *commit;
  85         unsigned char sha1[20];
  86         char *real_ref, ref[PATH_MAX], msg[PATH_MAX + 20];
  87         int forcing = 0;
  88
  89         snprintf(ref, sizeof ref, "refs/heads/%s", name);
  90         if (check_ref_format(ref))
  91                 die("'%s' is not a valid branch name.", name);
  92
  93         if (resolve_ref(ref, sha1, 1, NULL)) {
  94                 if (!force)
  95                         die("A branch named '%s' already exists.", name);
  96                 else if (!is_bare_repository() && !strcmp(head, name))
  97                         die("Cannot force update the current branch.");
  98                 forcing = 1;
  99         }
 100
 101         real_ref = NULL;
 102         if (get_sha1(start_name, sha1))
 103                 die("Not a valid object name: '%s'.", start_name);
 104
 105         switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
 106         case 0:
 107                 /* Not branching from any existing branch */
 108                 if (track == BRANCH_TRACK_EXPLICIT)
 109                         die("Cannot setup tracking information; starting point is not a branch.");
 110                 break;
 111         case 1:
 112                 /* Unique completion -- good */
 113                 break;
 114         default:
 115                 die("Ambiguous object name: '%s'.", start_name);
 116                 break;
 117         }
 118
 119         if ((commit = lookup_commit_reference(sha1)) == NULL)
 120                 die("Not a valid branch point: '%s'.", start_name);
 121         hashcpy(sha1, commit->object.sha1);
 122
 123         lock = lock_any_ref_for_update(ref, NULL, 0);
 124         if (!lock)
 125                 die("Failed to lock ref for update: %s.", strerror(errno));
 126
 127         if (reflog)
 128                 log_all_ref_updates = 1;
 129
 130         if (forcing)
 131                 snprintf(msg, sizeof msg, "branch: Reset from %s",
 132                          start_name);
 133         else
 134                 snprintf(msg, sizeof msg, "branch: Created from %s",
 135                          start_name);
 136
 137         if (real_ref && track)
 138                 setup_tracking(name, real_ref, track);
 139
 140         if (write_ref_sha1(lock, sha1, msg) < 0)
 141                 die("Failed to write ref: %s.", strerror(errno));
 142
 143         free(real_ref);
 144 }
 145
 146 void remove_branch_state(void)
 147 {
 148         unlink(git_path("MERGE_HEAD"));
 149         unlink(git_path("rr-cache/MERGE_RR"));
 150         unlink(git_path("MERGE_MSG"));
 151         unlink(git_path("SQUASH_MSG"));
 152 }