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