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