show-branch.c

   1 #include <stdlib.h>
   2 #include "cache.h"
   3 #include "commit.h"
   4 #include "refs.h"
   5
   6 static const char show_branch_usage[] =
   7 "git-show-branch [--all] [--heads] [--tags] [--more=count] [<refs>...]";
   8
   9 #define UNINTERESTING   01
  10
  11 #define REV_SHIFT        2
  12 #define MAX_REVS        29 /* should not exceed bits_per_int - REV_SHIFT */
  13
  14 static struct commit *interesting(struct commit_list *list)
  15 {
  16         while (list) {
  17                 struct commit *commit = list->item;
  18                 list = list->next;
  19                 if (commit->object.flags & UNINTERESTING)
  20                         continue;
  21                 return commit;
  22         }
  23         return NULL;
  24 }
  25
  26 static struct commit *pop_one_commit(struct commit_list **list_p)
  27 {
  28         struct commit *commit;
  29         struct commit_list *list;
  30         list = *list_p;
  31         commit = list->item;
  32         *list_p = list->next;
  33         free(list);
  34         return commit;
  35 }
  36
  37 struct commit_name {
  38         const char *head_name; /* which head's ancestor? */
  39         int generation; /* how many parents away from head_name */
  40 };
  41
  42 /* Name the commit as nth generation ancestor of head_name;
  43  * we count only the first-parent relationship for naming purposes.
  44  */
  45 static void name_commit(struct commit *commit, const char *head_name, int nth)
  46 {
  47         struct commit_name *name;
  48         if (!commit->object.util)
  49                 commit->object.util = xmalloc(sizeof(struct commit_name));
  50         name = commit->object.util;
  51         name->head_name = head_name;
  52         name->generation = nth;
  53 }
  54
  55 /* Parent is the first parent of the commit.  We may name it
  56  * as (n+1)th generation ancestor of the same head_name as
  57  * commit is nth generation ancestore of, if that generation
  58  * number is better than the name it already has.
  59  */
  60 static void name_parent(struct commit *commit, struct commit *parent)
  61 {
  62         struct commit_name *commit_name = commit->object.util;
  63         struct commit_name *parent_name = parent->object.util;
  64         if (!commit_name)
  65                 return;
  66         if (!parent_name ||
  67             commit_name->generation + 1 < parent_name->generation)
  68                 name_commit(parent, commit_name->head_name,
  69                             commit_name->generation + 1);
  70 }
  71
  72 static int name_first_parent_chain(struct commit *c)
  73 {
  74         int i = 0;
  75         while (c) {
  76                 struct commit *p;
  77                 if (!c->object.util)
  78                         break;
  79                 if (!c->parents)
  80                         break;
  81                 p = c->parents->item;
  82                 if (!p->object.util) {
  83                         name_parent(c, p);
  84                         i++;
  85                 }
  86                 c = p;
  87         }
  88         return i;
  89 }
  90
  91 static void name_commits(struct commit_list *list,
  92                          struct commit **rev,
  93                          char **ref_name,
  94                          int num_rev)
  95 {
  96         struct commit_list *cl;
  97         struct commit *c;
  98         int i;
  99
 100         /* First give names to the given heads */
 101         for (cl = list; cl; cl = cl->next) {
 102                 c = cl->item;
 103                 if (c->object.util)
 104                         continue;
 105                 for (i = 0; i < num_rev; i++) {
 106                         if (rev[i] == c) {
 107                                 name_commit(c, ref_name[i], 0);
 108                                 break;
 109                         }
 110                 }
 111         }
 112
 113         /* Then commits on the first parent ancestry chain */
 114         do {
 115                 i = 0;
 116                 for (cl = list; cl; cl = cl->next) {
 117                         i += name_first_parent_chain(cl->item);
 118                 }
 119         } while (i);
 120
 121         /* Finally, any unnamed commits */
 122         do {
 123                 i = 0;
 124                 for (cl = list; cl; cl = cl->next) {
 125                         struct commit_list *parents;
 126                         struct commit_name *n;
 127                         int nth;
 128                         c = cl->item;
 129                         if (!c->object.util)
 130                                 continue;
 131                         n = c->object.util;
 132                         parents = c->parents;
 133                         nth = 0;
 134                         while (parents) {
 135                                 struct commit *p = parents->item;
 136                                 char newname[1000];
 137                                 parents = parents->next;
 138                                 nth++;
 139                                 if (p->object.util)
 140                                         continue;
 141                                 sprintf(newname, "%s^%d", n->head_name, nth);
 142                                 name_commit(p, strdup(newname), 0);
 143                                 i++;
 144                                 name_first_parent_chain(p);
 145                         }
 146                 }
 147         } while (i);
 148 }
 149
 150 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
 151 {
 152         if (!commit->object.flags) {
 153                 insert_by_date(commit, seen_p);
 154                 return 1;
 155         }
 156         return 0;
 157 }
 158
 159 static void join_revs(struct commit_list **list_p,
 160                       struct commit_list **seen_p,
 161                       int num_rev, int extra)
 162 {
 163         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 164         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 165
 166         while (*list_p) {
 167                 struct commit_list *parents;
 168                 struct commit *commit = pop_one_commit(list_p);
 169                 int flags = commit->object.flags & all_mask;
 170                 int still_interesting = !!interesting(*list_p);
 171
 172                 if (!still_interesting && extra < 0)
 173                         break;
 174
 175                 mark_seen(commit, seen_p);
 176                 if ((flags & all_revs) == all_revs)
 177                         flags |= UNINTERESTING;
 178                 parents = commit->parents;
 179
 180                 while (parents) {
 181                         struct commit *p = parents->item;
 182                         int this_flag = p->object.flags;
 183                         parents = parents->next;
 184                         if ((this_flag & flags) == flags)
 185                                 continue;
 186                         parse_commit(p);
 187                         if (mark_seen(p, seen_p) && !still_interesting)
 188                                 extra--;
 189                         p->object.flags |= flags;
 190                         insert_by_date(p, list_p);
 191                 }
 192         }
 193 }
 194
 195 static void show_one_commit(struct commit *commit)
 196 {
 197         char pretty[128], *cp;
 198         struct commit_name *name = commit->object.util;
 199         pretty_print_commit(CMIT_FMT_ONELINE, commit->buffer, ~0,
 200                             pretty, sizeof(pretty));
 201         if (!strncmp(pretty, "[PATCH] ", 8))
 202                 cp = pretty + 8;
 203         else
 204                 cp = pretty;
 205         if (name && name->head_name) {
 206                 printf("[%s", name->head_name);
 207                 if (name->generation)
 208                         printf("~%d", name->generation);
 209                 printf("] ");
 210         }
 211         puts(cp);
 212 }
 213
 214 static char *ref_name[MAX_REVS + 1];
 215 static int ref_name_cnt;
 216
 217 static int compare_ref_name(const void *a_, const void *b_)
 218 {
 219         const char * const*a = a_, * const*b = b_;
 220         return strcmp(*a, *b);
 221 }
 222
 223 static void sort_ref_range(int bottom, int top)
 224 {
 225         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 226               compare_ref_name);
 227 }
 228
 229 static int append_ref(const char *refname, const unsigned char *sha1)
 230 {
 231         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 232         if (!commit)
 233                 return 0;
 234         if (MAX_REVS < ref_name_cnt) {
 235                 fprintf(stderr, "warning: ignoring %s; "
 236                         "cannot handle more than %d refs",
 237                         refname, MAX_REVS);
 238                 return 0;
 239         }
 240         ref_name[ref_name_cnt++] = strdup(refname);
 241         ref_name[ref_name_cnt] = NULL;
 242         return 0;
 243 }
 244
 245 static int append_head_ref(const char *refname, const unsigned char *sha1)
 246 {
 247         if (strncmp(refname, "refs/heads/", 11))
 248                 return 0;
 249         return append_ref(refname + 11, sha1);
 250 }
 251
 252 static int append_tag_ref(const char *refname, const unsigned char *sha1)
 253 {
 254         if (strncmp(refname, "refs/tags/", 10))
 255                 return 0;
 256         return append_ref(refname + 5, sha1);
 257 }
 258
 259 static void snarf_refs(int head, int tag)
 260 {
 261         if (head) {
 262                 int orig_cnt = ref_name_cnt;
 263                 for_each_ref(append_head_ref);
 264                 sort_ref_range(orig_cnt, ref_name_cnt);
 265         }
 266         if (tag) {
 267                 int orig_cnt = ref_name_cnt;
 268                 for_each_ref(append_tag_ref);
 269                 sort_ref_range(orig_cnt, ref_name_cnt);
 270         }
 271 }
 272
 273 static int rev_is_head(char *head_path, int headlen,
 274                        char *name,
 275                        unsigned char *head_sha1, unsigned char *sha1)
 276 {
 277         int namelen;
 278         if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
 279                 return 0;
 280         namelen = strlen(name);
 281         if ((headlen < namelen) ||
 282             memcmp(head_path + headlen - namelen, name, namelen))
 283                 return 0;
 284         if (headlen == namelen ||
 285             head_path[headlen - namelen - 1] == '/')
 286                 return 1;
 287         return 0;
 288 }
 289
 290 static int show_merge_base(struct commit_list *seen, int num_rev)
 291 {
 292         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 293         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 294
 295         while (seen) {
 296                 struct commit *commit = pop_one_commit(&seen);
 297                 int flags = commit->object.flags & all_mask;
 298                 if (!(flags & UNINTERESTING) &&
 299                     ((flags & all_revs) == all_revs)) {
 300                         puts(sha1_to_hex(commit->object.sha1));
 301                         return 0;
 302                 }
 303         }
 304         return 1;
 305 }
 306
 307 int main(int ac, char **av)
 308 {
 309         struct commit *rev[MAX_REVS], *commit;
 310         struct commit_list *list = NULL, *seen = NULL;
 311         int num_rev, i, extra = 0;
 312         int all_heads = 0, all_tags = 0;
 313         int all_mask, all_revs, shown_merge_point;
 314         char head_path[128];
 315         int head_path_len;
 316         unsigned char head_sha1[20];
 317         int merge_base = 0;
 318         char **label;
 319
 320         while (1 < ac && av[1][0] == '-') {
 321                 char *arg = av[1];
 322                 if (!strcmp(arg, "--all"))
 323                         all_heads = all_tags = 1;
 324                 else if (!strcmp(arg, "--heads"))
 325                         all_heads = 1;
 326                 else if (!strcmp(arg, "--tags"))
 327                         all_tags = 1;
 328                 else if (!strcmp(arg, "--more"))
 329                         extra = 1;
 330                 else if (!strncmp(arg, "--more=", 7)) {
 331                         extra = atoi(arg + 7);
 332                         if (extra < 0)
 333                                 usage(show_branch_usage);
 334                 }
 335                 else if (!strcmp(arg, "--merge-base"))
 336                         merge_base = 1;
 337                 else
 338                         usage(show_branch_usage);
 339                 ac--; av++;
 340         }
 341         ac--; av++;
 342
 343         if (all_heads + all_tags)
 344                 snarf_refs(all_heads, all_tags);
 345
 346         while (0 < ac) {
 347                 unsigned char revkey[20];
 348                 if (get_sha1(*av, revkey))
 349                         die("bad sha1 reference %s", *av);
 350                 append_ref(*av, revkey);
 351                 ac--; av++;
 352         }
 353
 354         /* If still no revs, then add heads */
 355         if (!ref_name_cnt)
 356                 snarf_refs(1, 0);
 357
 358         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 359                 unsigned char revkey[20];
 360
 361                 if (MAX_REVS <= num_rev)
 362                         die("cannot handle more than %d revs.", MAX_REVS);
 363                 if (get_sha1(ref_name[num_rev], revkey))
 364                         usage(show_branch_usage);
 365                 commit = lookup_commit_reference(revkey);
 366                 if (!commit)
 367                         die("cannot find commit %s (%s)",
 368                             ref_name[num_rev], revkey);
 369                 parse_commit(commit);
 370                 mark_seen(commit, &seen);
 371
 372                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 373                  * and so on.  REV_SHIFT bits from bit 0 are used for
 374                  * internal bookkeeping.
 375                  */
 376                 commit->object.flags |= 1u << (num_rev + REV_SHIFT);
 377                 insert_by_date(commit, &list);
 378                 rev[num_rev] = commit;
 379         }
 380         join_revs(&list, &seen, num_rev, extra);
 381
 382         head_path_len = readlink(".git/HEAD", head_path, sizeof(head_path)-1);
 383         if ((head_path_len < 0) || get_sha1("HEAD", head_sha1))
 384                 head_path[0] = 0;
 385         else
 386                 head_path[head_path_len] = 0;
 387
 388         if (merge_base)
 389                 return show_merge_base(seen, num_rev);
 390
 391         /* Show list */
 392         if (1 < num_rev) {
 393                 for (i = 0; i < num_rev; i++) {
 394                         int j;
 395                         int is_head = rev_is_head(head_path,
 396                                                   head_path_len,
 397                                                   ref_name[i],
 398                                                   head_sha1,
 399                                                   rev[i]->object.sha1);
 400                         for (j = 0; j < i; j++)
 401                                 putchar(' ');
 402                         printf("%c [%s] ", is_head ? '*' : '!', ref_name[i]);
 403                         show_one_commit(rev[i]);
 404                 }
 405                 for (i = 0; i < num_rev; i++)
 406                         putchar('-');
 407                 putchar('\n');
 408         }
 409
 410         /* Sort topologically */
 411         sort_in_topological_order(&seen);
 412
 413         /* Give names to commits */
 414         name_commits(seen, rev, ref_name, num_rev);
 415
 416         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 417         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 418         shown_merge_point = 0;
 419
 420         while (seen) {
 421                 struct commit *commit = pop_one_commit(&seen);
 422                 int this_flag = commit->object.flags;
 423                 int is_merge_point = (this_flag & all_revs) == all_revs;
 424                 static char *obvious[] = { "" };
 425
 426                 if (is_merge_point)
 427                         shown_merge_point = 1;
 428
 429                 if (1 < num_rev) {
 430                         for (i = 0; i < num_rev; i++)
 431                                 putchar((this_flag & (1u << (i + REV_SHIFT)))
 432                                         ? '+' : ' ');
 433                         putchar(' ');
 434                 }
 435                 show_one_commit(commit);
 436                 if (num_rev == 1)
 437                         label = obvious;
 438                 if (shown_merge_point && is_merge_point)
 439                         if (--extra < 0)
 440                                 break;
 441         }
 442         return 0;
 443 }