Andrew's git / gitweb.git / show-branch.c
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show-branch.con commit show-branch: Be nicer when running in a corrupt repository. (0a2ba73)
   1#include <stdlib.h>
   2#include "cache.h"
   3#include "commit.h"
   4#include "refs.h"
   5
   6static const char show_branch_usage[] =
   7"git-show-branch [--all] [--heads] [--tags] [--more=count | --list | --independent | --merge-base ] [<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
  14static 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
  26static 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
  37struct 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 */
  45static 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 */
  60static 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
  72static 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
  91static 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
 150static 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
 159static 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
 195static void show_one_commit(struct commit *commit)
 196{
 197        char pretty[128], *cp;
 198        struct commit_name *name = commit->object.util;
 199        if (commit->object.parsed)
 200                pretty_print_commit(CMIT_FMT_ONELINE, commit->buffer, ~0,
 201                                    pretty, sizeof(pretty));
 202        else
 203                strcpy(pretty, "(unavailable)");
 204        if (!strncmp(pretty, "[PATCH] ", 8))
 205                cp = pretty + 8;
 206        else
 207                cp = pretty;
 208        if (name && name->head_name) {
 209                printf("[%s", name->head_name);
 210                if (name->generation)
 211                        printf("~%d", name->generation);
 212                printf("] ");
 213        }
 214        puts(cp);
 215}
 216
 217static char *ref_name[MAX_REVS + 1];
 218static int ref_name_cnt;
 219
 220static int compare_ref_name(const void *a_, const void *b_)
 221{
 222        const char * const*a = a_, * const*b = b_;
 223        return strcmp(*a, *b);
 224}
 225
 226static void sort_ref_range(int bottom, int top)
 227{
 228        qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 229              compare_ref_name);
 230}
 231
 232static int append_ref(const char *refname, const unsigned char *sha1)
 233{
 234        struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 235        if (!commit)
 236                return 0;
 237        if (MAX_REVS < ref_name_cnt) {
 238                fprintf(stderr, "warning: ignoring %s; "
 239                        "cannot handle more than %d refs",
 240                        refname, MAX_REVS);
 241                return 0;
 242        }
 243        ref_name[ref_name_cnt++] = strdup(refname);
 244        ref_name[ref_name_cnt] = NULL;
 245        return 0;
 246}
 247
 248static int append_head_ref(const char *refname, const unsigned char *sha1)
 249{
 250        if (strncmp(refname, "refs/heads/", 11))
 251                return 0;
 252        return append_ref(refname + 11, sha1);
 253}
 254
 255static int append_tag_ref(const char *refname, const unsigned char *sha1)
 256{
 257        if (strncmp(refname, "refs/tags/", 10))
 258                return 0;
 259        return append_ref(refname + 5, sha1);
 260}
 261
 262static void snarf_refs(int head, int tag)
 263{
 264        if (head) {
 265                int orig_cnt = ref_name_cnt;
 266                for_each_ref(append_head_ref);
 267                sort_ref_range(orig_cnt, ref_name_cnt);
 268        }
 269        if (tag) {
 270                int orig_cnt = ref_name_cnt;
 271                for_each_ref(append_tag_ref);
 272                sort_ref_range(orig_cnt, ref_name_cnt);
 273        }
 274}
 275
 276static int rev_is_head(char *head_path, int headlen,
 277                       char *name,
 278                       unsigned char *head_sha1, unsigned char *sha1)
 279{
 280        int namelen;
 281        if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
 282                return 0;
 283        namelen = strlen(name);
 284        if ((headlen < namelen) ||
 285            memcmp(head_path + headlen - namelen, name, namelen))
 286                return 0;
 287        if (headlen == namelen ||
 288            head_path[headlen - namelen - 1] == '/')
 289                return 1;
 290        return 0;
 291}
 292
 293static int show_merge_base(struct commit_list *seen, int num_rev)
 294{
 295        int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 296        int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 297        int exit_status = 1;
 298
 299        while (seen) {
 300                struct commit *commit = pop_one_commit(&seen);
 301                int flags = commit->object.flags & all_mask;
 302                if (!(flags & UNINTERESTING) &&
 303                    ((flags & all_revs) == all_revs)) {
 304                        puts(sha1_to_hex(commit->object.sha1));
 305                        exit_status = 0;
 306                        commit->object.flags |= UNINTERESTING;
 307                }
 308        }
 309        return exit_status;
 310}
 311
 312static int show_independent(struct commit **rev,
 313                            int num_rev,
 314                            char **ref_name,
 315                            unsigned int *rev_mask)
 316{
 317        int i;
 318
 319        for (i = 0; i < num_rev; i++) {
 320                struct commit *commit = rev[i];
 321                unsigned int flag = rev_mask[i];
 322
 323                if (commit->object.flags == flag)
 324                        puts(sha1_to_hex(commit->object.sha1));
 325                commit->object.flags |= UNINTERESTING;
 326        }
 327        return 0;
 328}
 329
 330int main(int ac, char **av)
 331{
 332        struct commit *rev[MAX_REVS], *commit;
 333        struct commit_list *list = NULL, *seen = NULL;
 334        unsigned int rev_mask[MAX_REVS];
 335        int num_rev, i, extra = 0;
 336        int all_heads = 0, all_tags = 0;
 337        int all_mask, all_revs, shown_merge_point;
 338        char head_path[128];
 339        int head_path_len;
 340        unsigned char head_sha1[20];
 341        int merge_base = 0;
 342        int independent = 0;
 343        char **label;
 344
 345        setup_git_directory();
 346
 347        while (1 < ac && av[1][0] == '-') {
 348                char *arg = av[1];
 349                if (!strcmp(arg, "--all"))
 350                        all_heads = all_tags = 1;
 351                else if (!strcmp(arg, "--heads"))
 352                        all_heads = 1;
 353                else if (!strcmp(arg, "--tags"))
 354                        all_tags = 1;
 355                else if (!strcmp(arg, "--more"))
 356                        extra = 1;
 357                else if (!strcmp(arg, "--list"))
 358                        extra = -1;
 359                else if (!strncmp(arg, "--more=", 7))
 360                        extra = atoi(arg + 7);
 361                else if (!strcmp(arg, "--merge-base"))
 362                        merge_base = 1;
 363                else if (!strcmp(arg, "--independent"))
 364                        independent = 1;
 365                else
 366                        usage(show_branch_usage);
 367                ac--; av++;
 368        }
 369        ac--; av++;
 370
 371        /* Only one of these is allowed */
 372        if (1 < independent + merge_base + (extra != 0))
 373                usage(show_branch_usage);
 374
 375        if (all_heads + all_tags)
 376                snarf_refs(all_heads, all_tags);
 377
 378        while (0 < ac) {
 379                unsigned char revkey[20];
 380                if (get_sha1(*av, revkey))
 381                        die("bad sha1 reference %s", *av);
 382                append_ref(*av, revkey);
 383                ac--; av++;
 384        }
 385
 386        /* If still no revs, then add heads */
 387        if (!ref_name_cnt)
 388                snarf_refs(1, 0);
 389
 390        for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 391                unsigned char revkey[20];
 392                unsigned int flag = 1u << (num_rev + REV_SHIFT);
 393
 394                if (MAX_REVS <= num_rev)
 395                        die("cannot handle more than %d revs.", MAX_REVS);
 396                if (get_sha1(ref_name[num_rev], revkey))
 397                        usage(show_branch_usage);
 398                commit = lookup_commit_reference(revkey);
 399                if (!commit)
 400                        die("cannot find commit %s (%s)",
 401                            ref_name[num_rev], revkey);
 402                parse_commit(commit);
 403                mark_seen(commit, &seen);
 404
 405                /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 406                 * and so on.  REV_SHIFT bits from bit 0 are used for
 407                 * internal bookkeeping.
 408                 */
 409                commit->object.flags |= flag;
 410                if (commit->object.flags == flag)
 411                        insert_by_date(commit, &list);
 412                rev[num_rev] = commit;
 413        }
 414        for (i = 0; i < num_rev; i++)
 415                rev_mask[i] = rev[i]->object.flags;
 416
 417        if (0 <= extra)
 418                join_revs(&list, &seen, num_rev, extra);
 419
 420        head_path_len = readlink(".git/HEAD", head_path, sizeof(head_path)-1);
 421        if ((head_path_len < 0) || get_sha1("HEAD", head_sha1))
 422                head_path[0] = 0;
 423        else
 424                head_path[head_path_len] = 0;
 425
 426        if (merge_base)
 427                return show_merge_base(seen, num_rev);
 428
 429        if (independent)
 430                return show_independent(rev, num_rev, ref_name, rev_mask);
 431
 432        /* Show list; --more=-1 means list-only */
 433        if (1 < num_rev || extra < 0) {
 434                for (i = 0; i < num_rev; i++) {
 435                        int j;
 436                        int is_head = rev_is_head(head_path,
 437                                                  head_path_len,
 438                                                  ref_name[i],
 439                                                  head_sha1,
 440                                                  rev[i]->object.sha1);
 441                        if (extra < 0)
 442                                printf("%c [%s] ",
 443                                       is_head ? '*' : ' ', ref_name[i]);
 444                        else {
 445                                for (j = 0; j < i; j++)
 446                                        putchar(' ');
 447                                printf("%c [%s] ",
 448                                       is_head ? '*' : '!', ref_name[i]);
 449                        }
 450                        show_one_commit(rev[i]);
 451                }
 452                if (0 <= extra) {
 453                        for (i = 0; i < num_rev; i++)
 454                                putchar('-');
 455                        putchar('\n');
 456                }
 457        }
 458        if (extra < 0)
 459                exit(0);
 460
 461        /* Sort topologically */
 462        sort_in_topological_order(&seen);
 463
 464        /* Give names to commits */
 465        name_commits(seen, rev, ref_name, num_rev);
 466
 467        all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 468        all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 469        shown_merge_point = 0;
 470
 471        while (seen) {
 472                struct commit *commit = pop_one_commit(&seen);
 473                int this_flag = commit->object.flags;
 474                int is_merge_point = (this_flag & all_revs) == all_revs;
 475                static char *obvious[] = { "" };
 476
 477                if (is_merge_point)
 478                        shown_merge_point = 1;
 479
 480                if (1 < num_rev) {
 481                        for (i = 0; i < num_rev; i++)
 482                                putchar((this_flag & (1u << (i + REV_SHIFT)))
 483                                        ? '+' : ' ');
 484                        putchar(' ');
 485                }
 486                show_one_commit(commit);
 487                if (num_rev == 1)
 488                        label = obvious;
 489                if (shown_merge_point && is_merge_point)
 490                        if (--extra < 0)
 491                                break;
 492        }
 493        return 0;
 494}