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         strbuf_release(&key);
  78
  79         if (flag & BRANCH_CONFIG_VERBOSE) {
  80                 if (remote_is_branch && origin)
  81                         printf(rebasing ?
  82                                "Branch %s set up to track remote branch %s from %s by rebasing.\n" :
  83                                "Branch %s set up to track remote branch %s from %s.\n",
  84                                local, shortname, origin);
  85                 else if (remote_is_branch && !origin)
  86                         printf(rebasing ?
  87                                "Branch %s set up to track local branch %s by rebasing.\n" :
  88                                "Branch %s set up to track local branch %s.\n",
  89                                local, shortname);
  90                 else if (!remote_is_branch && origin)
  91                         printf(rebasing ?
  92                                "Branch %s set up to track remote ref %s by rebasing.\n" :
  93                                "Branch %s set up to track remote ref %s.\n",
  94                                local, remote);
  95                 else if (!remote_is_branch && !origin)
  96                         printf(rebasing ?
  97                                "Branch %s set up to track local ref %s by rebasing.\n" :
  98                                "Branch %s set up to track local ref %s.\n",
  99                                local, remote);
 100                 else
 101                         die("BUG: impossible combination of %d and %p",
 102                             remote_is_branch, origin);
 103         }
 104 }
 105
 106 /*
 107  * This is called when new_ref is branched off of orig_ref, and tries
 108  * to infer the settings for branch.<new_ref>.{remote,merge} from the
 109  * config.
 110  */
 111 static int setup_tracking(const char *new_ref, const char *orig_ref,
 112                           enum branch_track track, int quiet)
 113 {
 114         struct tracking tracking;
 115         int config_flags = quiet ? 0 : BRANCH_CONFIG_VERBOSE;
 116
 117         if (strlen(new_ref) > 1024 - 7 - 7 - 1)
 118                 return error("Tracking not set up: name too long: %s",
 119                                 new_ref);
 120
 121         memset(&tracking, 0, sizeof(tracking));
 122         tracking.spec.dst = (char *)orig_ref;
 123         if (for_each_remote(find_tracked_branch, &tracking))
 124                 return 1;
 125
 126         if (!tracking.matches)
 127                 switch (track) {
 128                 case BRANCH_TRACK_ALWAYS:
 129                 case BRANCH_TRACK_EXPLICIT:
 130                 case BRANCH_TRACK_OVERRIDE:
 131                         break;
 132                 default:
 133                         return 1;
 134                 }
 135
 136         if (tracking.matches > 1)
 137                 return error("Not tracking: ambiguous information for ref %s",
 138                                 orig_ref);
 139
 140         install_branch_config(config_flags, new_ref, tracking.remote,
 141                               tracking.src ? tracking.src : orig_ref);
 142
 143         free(tracking.src);
 144         return 0;
 145 }
 146
 147 struct branch_desc_cb {
 148         const char *config_name;
 149         const char *value;
 150 };
 151
 152 static int read_branch_desc_cb(const char *var, const char *value, void *cb)
 153 {
 154         struct branch_desc_cb *desc = cb;
 155         if (strcmp(desc->config_name, var))
 156                 return 0;
 157         free((char *)desc->value);
 158         return git_config_string(&desc->value, var, value);
 159 }
 160
 161 int read_branch_desc(struct strbuf *buf, const char *branch_name)
 162 {
 163         struct branch_desc_cb cb;
 164         struct strbuf name = STRBUF_INIT;
 165         strbuf_addf(&name, "branch.%s.description", branch_name);
 166         cb.config_name = name.buf;
 167         cb.value = NULL;
 168         if (git_config(read_branch_desc_cb, &cb) < 0) {
 169                 strbuf_release(&name);
 170                 return -1;
 171         }
 172         if (cb.value)
 173                 strbuf_addstr(buf, cb.value);
 174         strbuf_release(&name);
 175         return 0;
 176 }
 177
 178 int validate_new_branchname(const char *name, struct strbuf *ref,
 179                             int force, int attr_only)
 180 {
 181         if (strbuf_check_branch_ref(ref, name))
 182                 die("'%s' is not a valid branch name.", name);
 183
 184         if (!ref_exists(ref->buf))
 185                 return 0;
 186         else if (!force && !attr_only)
 187                 die("A branch named '%s' already exists.", ref->buf + strlen("refs/heads/"));
 188
 189         if (!attr_only) {
 190                 const char *head;
 191                 unsigned char sha1[20];
 192
 193                 head = resolve_ref_unsafe("HEAD", sha1, 0, NULL);
 194                 if (!is_bare_repository() && head && !strcmp(head, ref->buf))
 195                         die("Cannot force update the current branch.");
 196         }
 197         return 1;
 198 }
 199
 200 static const char upstream_not_branch[] =
 201 N_("Cannot setup tracking information; starting point is not a branch.");
 202 static const char upstream_missing[] =
 203 N_("Cannot setup tracking information; starting point does not exist");
 204
 205 void create_branch(const char *head,
 206                    const char *name, const char *start_name,
 207                    int force, int reflog, int clobber_head,
 208                    int quiet, enum branch_track track)
 209 {
 210         struct ref_lock *lock = NULL;
 211         struct commit *commit;
 212         unsigned char sha1[20];
 213         char *real_ref, msg[PATH_MAX + 20];
 214         struct strbuf ref = STRBUF_INIT;
 215         int forcing = 0;
 216         int dont_change_ref = 0;
 217         int explicit_tracking = 0;
 218
 219         if (track == BRANCH_TRACK_EXPLICIT || track == BRANCH_TRACK_OVERRIDE)
 220                 explicit_tracking = 1;
 221
 222         if (validate_new_branchname(name, &ref, force,
 223                                     track == BRANCH_TRACK_OVERRIDE ||
 224                                     clobber_head)) {
 225                 if (!force)
 226                         dont_change_ref = 1;
 227                 else
 228                         forcing = 1;
 229         }
 230
 231         real_ref = NULL;
 232         if (get_sha1(start_name, sha1)) {
 233                 if (explicit_tracking)
 234                         die(_(upstream_missing));
 235                 die("Not a valid object name: '%s'.", start_name);
 236         }
 237
 238         switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
 239         case 0:
 240                 /* Not branching from any existing branch */
 241                 if (explicit_tracking)
 242                         die(_(upstream_not_branch));
 243                 break;
 244         case 1:
 245                 /* Unique completion -- good, only if it is a real branch */
 246                 if (prefixcmp(real_ref, "refs/heads/") &&
 247                     prefixcmp(real_ref, "refs/remotes/")) {
 248                         if (explicit_tracking)
 249                                 die(_(upstream_not_branch));
 250                         else
 251                                 real_ref = NULL;
 252                 }
 253                 break;
 254         default:
 255                 die("Ambiguous object name: '%s'.", start_name);
 256                 break;
 257         }
 258
 259         if ((commit = lookup_commit_reference(sha1)) == NULL)
 260                 die("Not a valid branch point: '%s'.", start_name);
 261         hashcpy(sha1, commit->object.sha1);
 262
 263         if (!dont_change_ref) {
 264                 lock = lock_any_ref_for_update(ref.buf, NULL, 0);
 265                 if (!lock)
 266                         die_errno("Failed to lock ref for update");
 267         }
 268
 269         if (reflog)
 270                 log_all_ref_updates = 1;
 271
 272         if (forcing)
 273                 snprintf(msg, sizeof msg, "branch: Reset to %s",
 274                          start_name);
 275         else if (!dont_change_ref)
 276                 snprintf(msg, sizeof msg, "branch: Created from %s",
 277                          start_name);
 278
 279         if (real_ref && track)
 280                 setup_tracking(ref.buf+11, real_ref, track, quiet);
 281
 282         if (!dont_change_ref)
 283                 if (write_ref_sha1(lock, sha1, msg) < 0)
 284                         die_errno("Failed to write ref");
 285
 286         strbuf_release(&ref);
 287         free(real_ref);
 288 }
 289
 290 void remove_branch_state(void)
 291 {
 292         unlink(git_path("CHERRY_PICK_HEAD"));
 293         unlink(git_path("REVERT_HEAD"));
 294         unlink(git_path("MERGE_HEAD"));
 295         unlink(git_path("MERGE_RR"));
 296         unlink(git_path("MERGE_MSG"));
 297         unlink(git_path("MERGE_MODE"));
 298         unlink(git_path("SQUASH_MSG"));
 299 }