server-info.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6
   7 /* refs */
   8 static FILE *info_ref_fp;
   9
  10 static int add_info_ref(const char *path, const unsigned char *sha1)
  11 {
  12         struct object *o = parse_object(sha1);
  13
  14         fprintf(info_ref_fp, "%s        %s\n", sha1_to_hex(sha1), path);
  15         if (o->type == tag_type) {
  16                 o = deref_tag(o);
  17                 fprintf(info_ref_fp, "%s        %s^{}\n",
  18                         sha1_to_hex(o->sha1), path);
  19         }
  20         return 0;
  21 }
  22
  23 static int update_info_refs(int force)
  24 {
  25         char *path0 = strdup(git_path("info/refs"));
  26         int len = strlen(path0);
  27         char *path1 = xmalloc(len + 2);
  28
  29         strcpy(path1, path0);
  30         strcpy(path1 + len, "+");
  31
  32         safe_create_leading_directories(path0);
  33         info_ref_fp = fopen(path1, "w");
  34         if (!info_ref_fp)
  35                 return error("unable to update %s", path0);
  36         for_each_ref(add_info_ref);
  37         fclose(info_ref_fp);
  38         rename(path1, path0);
  39         free(path0);
  40         free(path1);
  41         return 0;
  42 }
  43
  44 /* packs */
  45 static struct pack_info {
  46         unsigned long latest;
  47         struct packed_git *p;
  48         int old_num;
  49         int new_num;
  50         int nr_alloc;
  51         int nr_heads;
  52         unsigned char (*head)[20];
  53         char dep[0]; /* more */
  54 } **info;
  55 static int num_pack;
  56 static const char *objdir;
  57 static int objdirlen;
  58
  59 static struct object *parse_object_cheap(const unsigned char *sha1)
  60 {
  61         struct object *o;
  62
  63         if ((o = parse_object(sha1)) == NULL)
  64                 return NULL;
  65         if (o->type == commit_type) {
  66                 struct commit *commit = (struct commit *)o;
  67                 free(commit->buffer);
  68                 commit->buffer = NULL;
  69         } else if (o->type == tree_type) {
  70                 struct tree *tree = (struct tree *)o;
  71                 struct tree_entry_list *e, *n;
  72                 for (e = tree->entries; e; e = n) {
  73                         free(e->name);
  74                         e->name = NULL;
  75                         n = e->next;
  76                         free(e);
  77                 }
  78                 tree->entries = NULL;
  79         }
  80         return o;
  81 }
  82
  83 static struct pack_info *find_pack_by_name(const char *name)
  84 {
  85         int i;
  86         for (i = 0; i < num_pack; i++) {
  87                 struct packed_git *p = info[i]->p;
  88                 /* skip "/pack/" after ".git/objects" */
  89                 if (!strcmp(p->pack_name + objdirlen + 6, name))
  90                         return info[i];
  91         }
  92         return NULL;
  93 }
  94
  95 static struct pack_info *find_pack_by_old_num(int old_num)
  96 {
  97         int i;
  98         for (i = 0; i < num_pack; i++)
  99                 if (info[i]->old_num == old_num)
 100                         return info[i];
 101         return NULL;
 102 }
 103
 104 static int add_head_def(struct pack_info *this, unsigned char *sha1)
 105 {
 106         if (this->nr_alloc <= this->nr_heads) {
 107                 this->nr_alloc = alloc_nr(this->nr_alloc);
 108                 this->head = xrealloc(this->head, this->nr_alloc * 20);
 109         }
 110         memcpy(this->head[this->nr_heads++], sha1, 20);
 111         return 0;
 112 }
 113
 114 /* Returns non-zero when we detect that the info in the
 115  * old file is useless.
 116  */
 117 static int parse_pack_def(const char *line, int old_cnt)
 118 {
 119         struct pack_info *i = find_pack_by_name(line + 2);
 120         if (i) {
 121                 i->old_num = old_cnt;
 122                 return 0;
 123         }
 124         else {
 125                 /* The file describes a pack that is no longer here;
 126                  * dependencies between packs needs to be recalculated.
 127                  */
 128                 return 1;
 129         }
 130 }
 131
 132 /* Returns non-zero when we detect that the info in the
 133  * old file is useless.
 134  */
 135 static int parse_depend_def(char *line)
 136 {
 137         unsigned long num;
 138         char *cp, *ep;
 139         struct pack_info *this, *that;
 140
 141         cp = line + 2;
 142         num = strtoul(cp, &ep, 10);
 143         if (ep == cp)
 144                 return error("invalid input %s", line);
 145         this = find_pack_by_old_num(num);
 146         if (!this)
 147                 return 0;
 148         while (ep && *(cp = ep)) {
 149                 num = strtoul(cp, &ep, 10);
 150                 if (ep == cp)
 151                         break;
 152                 that = find_pack_by_old_num(num);
 153                 if (!that)
 154                         /* The pack this one depends on does not
 155                          * exist; this should not happen because
 156                          * we write out the list of packs first and
 157                          * then dependency information, but it means
 158                          * the file is useless anyway.
 159                          */
 160                         return 1;
 161                 this->dep[that->new_num] = 1;
 162         }
 163         return 0;
 164 }
 165
 166 /* Returns non-zero when we detect that the info in the
 167  * old file is useless.
 168  */
 169 static int parse_head_def(char *line)
 170 {
 171         unsigned char sha1[20];
 172         unsigned long num;
 173         char *cp, *ep;
 174         struct pack_info *this;
 175         struct object *o;
 176
 177         cp = line + 2;
 178         num = strtoul(cp, &ep, 10);
 179         if (ep == cp || *ep++ != ' ')
 180                 return error("invalid input ix %s", line);
 181         this = find_pack_by_old_num(num);
 182         if (!this)
 183                 return 1; /* You know the drill. */
 184         if (get_sha1_hex(ep, sha1) || ep[40] != ' ')
 185                 return error("invalid input sha1 %s (%s)", line, ep);
 186         if ((o = parse_object_cheap(sha1)) == NULL)
 187                 return error("no such object: %s", line);
 188         return add_head_def(this, sha1);
 189 }
 190
 191 /* Returns non-zero when we detect that the info in the
 192  * old file is useless.
 193  */
 194 static int read_pack_info_file(const char *infofile)
 195 {
 196         FILE *fp;
 197         char line[1000];
 198         int old_cnt = 0;
 199
 200         fp = fopen(infofile, "r");
 201         if (!fp)
 202                 return 1; /* nonexisting is not an error. */
 203
 204         while (fgets(line, sizeof(line), fp)) {
 205                 int len = strlen(line);
 206                 if (line[len-1] == '\n')
 207                         line[len-1] = 0;
 208
 209                 switch (line[0]) {
 210                 case 'P': /* P name */
 211                         if (parse_pack_def(line, old_cnt++))
 212                                 goto out_stale;
 213                         break;
 214                 case 'D': /* D ix dep-ix1 dep-ix2... */
 215                         if (parse_depend_def(line))
 216                                 goto out_stale;
 217                         break;
 218                 case 'T': /* T ix sha1 type */
 219                         if (parse_head_def(line))
 220                                 goto out_stale;
 221                         break;
 222                 default:
 223                         error("unrecognized: %s", line);
 224                         break;
 225                 }
 226         }
 227         fclose(fp);
 228         return 0;
 229  out_stale:
 230         fclose(fp);
 231         return 1;
 232 }
 233
 234 /* We sort the packs according to the date of the latest commit.  That
 235  * in turn indicates how young the pack is, and in general we would
 236  * want to depend on younger packs.
 237  */
 238 static unsigned long get_latest_commit_date(struct packed_git *p)
 239 {
 240         unsigned char sha1[20];
 241         struct object *o;
 242         int num = num_packed_objects(p);
 243         int i;
 244         unsigned long latest = 0;
 245
 246         for (i = 0; i < num; i++) {
 247                 if (nth_packed_object_sha1(p, i, sha1))
 248                         die("corrupt pack file %s?", p->pack_name);
 249                 if ((o = parse_object_cheap(sha1)) == NULL)
 250                         die("cannot parse %s", sha1_to_hex(sha1));
 251                 if (o->type == commit_type) {
 252                         struct commit *commit = (struct commit *)o;
 253                         if (latest < commit->date)
 254                                 latest = commit->date;
 255                 }
 256         }
 257         return latest;
 258 }
 259
 260 static int compare_info(const void *a_, const void *b_)
 261 {
 262         struct pack_info * const* a = a_;
 263         struct pack_info * const* b = b_;
 264
 265         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 266                 /* Keep the order in the original */
 267                 return (*a)->old_num - (*b)->old_num;
 268         else if (0 <= (*a)->old_num)
 269                 /* Only A existed in the original so B is obviously newer */
 270                 return -1;
 271         else if (0 <= (*b)->old_num)
 272                 /* The other way around. */
 273                 return 1;
 274
 275         if ((*a)->latest < (*b)->latest)
 276                 return -1;
 277         else if ((*a)->latest == (*b)->latest)
 278                 return 0;
 279         else
 280                 return 1;
 281 }
 282
 283 static void init_pack_info(const char *infofile, int force)
 284 {
 285         struct packed_git *p;
 286         int stale;
 287         int i = 0;
 288         char *dep_temp;
 289
 290         objdir = get_object_directory();
 291         objdirlen = strlen(objdir);
 292
 293         prepare_packed_git();
 294         for (p = packed_git; p; p = p->next) {
 295                 /* we ignore things on alternate path since they are
 296                  * not available to the pullers in general.
 297                  */
 298                 if (strncmp(p->pack_name, objdir, objdirlen) ||
 299                     strncmp(p->pack_name + objdirlen, "/pack/", 6))
 300                         continue;
 301                 i++;
 302         }
 303         num_pack = i;
 304         info = xcalloc(num_pack, sizeof(struct pack_info *));
 305         for (i = 0, p = packed_git; p; p = p->next) {
 306                 if (strncmp(p->pack_name, objdir, objdirlen) ||
 307                     p->pack_name[objdirlen] != '/')
 308                         continue;
 309                 info[i] = xcalloc(1, sizeof(struct pack_info) + num_pack);
 310                 info[i]->p = p;
 311                 info[i]->old_num = -1;
 312                 i++;
 313         }
 314
 315         if (infofile && !force)
 316                 stale = read_pack_info_file(infofile);
 317         else
 318                 stale = 1;
 319
 320         for (i = 0; i < num_pack; i++) {
 321                 if (stale) {
 322                         info[i]->old_num = -1;
 323                         memset(info[i]->dep, 0, num_pack);
 324                         info[i]->nr_heads = 0;
 325                 }
 326                 if (info[i]->old_num < 0)
 327                         info[i]->latest = get_latest_commit_date(info[i]->p);
 328         }
 329
 330         qsort(info, num_pack, sizeof(info[0]), compare_info);
 331         for (i = 0; i < num_pack; i++)
 332                 info[i]->new_num = i;
 333
 334         /* we need to fix up the dependency information
 335          * for the old ones.
 336          */
 337         dep_temp = NULL;
 338         for (i = 0; i < num_pack; i++) {
 339                 int old;
 340
 341                 if (info[i]->old_num < 0)
 342                         continue;
 343                 if (! dep_temp)
 344                         dep_temp = xmalloc(num_pack);
 345                 memset(dep_temp, 0, num_pack);
 346                 for (old = 0; old < num_pack; old++) {
 347                         struct pack_info *base;
 348                         if (!info[i]->dep[old])
 349                                 continue;
 350                         base = find_pack_by_old_num(old);
 351                         if (!base)
 352                                 die("internal error renumbering");
 353                         dep_temp[base->new_num] = 1;
 354                 }
 355                 memcpy(info[i]->dep, dep_temp, num_pack);
 356         }
 357         free(dep_temp);
 358 }
 359
 360 static void write_pack_info_file(FILE *fp)
 361 {
 362         int i, j;
 363         for (i = 0; i < num_pack; i++)
 364                 fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6);
 365
 366         for (i = 0; i < num_pack; i++) {
 367                 fprintf(fp, "D %1d", i);
 368                 for (j = 0; j < num_pack; j++) {
 369                         if ((i == j) || !(info[i]->dep[j]))
 370                                 continue;
 371                         fprintf(fp, " %1d", j);
 372                 }
 373                 fputc('\n', fp);
 374         }
 375
 376         for (i = 0; i < num_pack; i++) {
 377                 struct pack_info *this = info[i];
 378                 for (j = 0; j < this->nr_heads; j++) {
 379                         struct object *o = lookup_object(this->head[j]);
 380                         fprintf(fp, "T %1d %s %s\n",
 381                                 i, sha1_to_hex(this->head[j]), o->type);
 382                 }
 383         }
 384
 385 }
 386
 387 #define REFERENCED 01
 388 #define INTERNAL  02
 389 #define EMITTED   04
 390
 391 static void show(struct object *o, int pack_ix)
 392 {
 393         /*
 394          * We are interested in objects that are not referenced,
 395          * and objects that are referenced but not internal.
 396          */
 397         if (o->flags & EMITTED)
 398                 return;
 399
 400         if (!(o->flags & REFERENCED))
 401                 add_head_def(info[pack_ix], o->sha1);
 402         else if ((o->flags & REFERENCED) && !(o->flags & INTERNAL)) {
 403                 int i;
 404
 405                 /* Which pack contains this object?  That is what
 406                  * pack_ix can depend on.  We earlier sorted info
 407                  * array from youngest to oldest, so try newer packs
 408                  * first to favor them here.
 409                  */
 410                 for (i = num_pack - 1; 0 <= i; i--) {
 411                         struct packed_git *p = info[i]->p;
 412                         struct pack_entry ent;
 413                         if (find_pack_entry_one(o->sha1, &ent, p)) {
 414                                 info[pack_ix]->dep[i] = 1;
 415                                 break;
 416                         }
 417                 }
 418         }
 419         o->flags |= EMITTED;
 420 }
 421
 422 static void find_pack_info_one(int pack_ix)
 423 {
 424         unsigned char sha1[20];
 425         struct object *o;
 426         struct object_list *ref;
 427         int i;
 428         struct packed_git *p = info[pack_ix]->p;
 429         int num = num_packed_objects(p);
 430
 431         /* Scan objects, clear flags from all the edge ones and
 432          * internal ones, possibly marked in the previous round.
 433          */
 434         for (i = 0; i < num; i++) {
 435                 if (nth_packed_object_sha1(p, i, sha1))
 436                         die("corrupt pack file %s?", p->pack_name);
 437                 if ((o = lookup_object(sha1)) == NULL)
 438                         die("cannot parse %s", sha1_to_hex(sha1));
 439                 for (ref = o->refs; ref; ref = ref->next)
 440                         ref->item->flags = 0;
 441                 o->flags = 0;
 442         }
 443
 444         /* Mark all the internal ones */
 445         for (i = 0; i < num; i++) {
 446                 if (nth_packed_object_sha1(p, i, sha1))
 447                         die("corrupt pack file %s?", p->pack_name);
 448                 if ((o = lookup_object(sha1)) == NULL)
 449                         die("cannot find %s", sha1_to_hex(sha1));
 450                 for (ref = o->refs; ref; ref = ref->next)
 451                         ref->item->flags |= REFERENCED;
 452                 o->flags |= INTERNAL;
 453         }
 454
 455         for (i = 0; i < num; i++) {
 456                 if (nth_packed_object_sha1(p, i, sha1))
 457                         die("corrupt pack file %s?", p->pack_name);
 458                 if ((o = lookup_object(sha1)) == NULL)
 459                         die("cannot find %s", sha1_to_hex(sha1));
 460
 461                 show(o, pack_ix);
 462                 for (ref = o->refs; ref; ref = ref->next)
 463                         show(ref->item, pack_ix);
 464         }
 465
 466 }
 467
 468 static void find_pack_info(void)
 469 {
 470         int i;
 471         for (i = 0; i < num_pack; i++) {
 472                 /* The packed objects are cast in stone, and a head
 473                  * in a pack will stay as head, so is the set of missing
 474                  * objects.  If the repo has been reorganized and we
 475                  * are missing some packs available back then, we have
 476                  * already discarded the info read from the file, so
 477                  * we will find (old_num < 0) in that case.
 478                  */
 479                 if (0 <= info[i]->old_num)
 480                         continue;
 481                 find_pack_info_one(i);
 482         }
 483 }
 484
 485 static int update_info_packs(int force)
 486 {
 487         char infofile[PATH_MAX];
 488         char name[PATH_MAX];
 489         int namelen;
 490         FILE *fp;
 491
 492         namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
 493         strcpy(name, infofile);
 494         strcpy(name + namelen, "+");
 495
 496         init_pack_info(infofile, force);
 497         find_pack_info();
 498
 499         safe_create_leading_directories(name);
 500         fp = fopen(name, "w");
 501         if (!fp)
 502                 return error("cannot open %s", name);
 503         write_pack_info_file(fp);
 504         fclose(fp);
 505         rename(name, infofile);
 506         return 0;
 507 }
 508
 509 /* public */
 510 int update_server_info(int force)
 511 {
 512         /* We would add more dumb-server support files later,
 513          * including index of available pack files and their
 514          * intended audiences.
 515          */
 516         int errs = 0;
 517
 518         errs = errs | update_info_refs(force);
 519         errs = errs | update_info_packs(force);
 520
 521         return errs;
 522 }