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, path, 0);
  17                 if (o)
  18                         fprintf(info_ref_fp, "%s        %s^{}\n",
  19                                 sha1_to_hex(o->sha1), path);
  20         }
  21         return 0;
  22 }
  23
  24 static int update_info_refs(int force)
  25 {
  26         char *path0 = strdup(git_path("info/refs"));
  27         int len = strlen(path0);
  28         char *path1 = xmalloc(len + 2);
  29
  30         strcpy(path1, path0);
  31         strcpy(path1 + len, "+");
  32
  33         safe_create_leading_directories(path0);
  34         info_ref_fp = fopen(path1, "w");
  35         if (!info_ref_fp)
  36                 return error("unable to update %s", path0);
  37         for_each_ref(add_info_ref);
  38         fclose(info_ref_fp);
  39         rename(path1, path0);
  40         free(path0);
  41         free(path1);
  42         return 0;
  43 }
  44
  45 /* packs */
  46 static struct pack_info {
  47         unsigned long latest;
  48         struct packed_git *p;
  49         int old_num;
  50         int new_num;
  51         int nr_alloc;
  52         int nr_heads;
  53         unsigned char (*head)[20];
  54         char dep[0]; /* more */
  55 } **info;
  56 static int num_pack;
  57 static const char *objdir;
  58 static int objdirlen;
  59
  60 static struct object *parse_object_cheap(const unsigned char *sha1)
  61 {
  62         struct object *o;
  63
  64         if ((o = parse_object(sha1)) == NULL)
  65                 return NULL;
  66         if (o->type == commit_type) {
  67                 struct commit *commit = (struct commit *)o;
  68                 free(commit->buffer);
  69                 commit->buffer = NULL;
  70         } else if (o->type == tree_type) {
  71                 struct tree *tree = (struct tree *)o;
  72                 struct tree_entry_list *e, *n;
  73                 for (e = tree->entries; e; e = n) {
  74                         free(e->name);
  75                         e->name = NULL;
  76                         n = e->next;
  77                         free(e);
  78                 }
  79                 tree->entries = NULL;
  80         }
  81         return o;
  82 }
  83
  84 static struct pack_info *find_pack_by_name(const char *name)
  85 {
  86         int i;
  87         for (i = 0; i < num_pack; i++) {
  88                 struct packed_git *p = info[i]->p;
  89                 /* skip "/pack/" after ".git/objects" */
  90                 if (!strcmp(p->pack_name + objdirlen + 6, name))
  91                         return info[i];
  92         }
  93         return NULL;
  94 }
  95
  96 static struct pack_info *find_pack_by_old_num(int old_num)
  97 {
  98         int i;
  99         for (i = 0; i < num_pack; i++)
 100                 if (info[i]->old_num == old_num)
 101                         return info[i];
 102         return NULL;
 103 }
 104
 105 static int add_head_def(struct pack_info *this, unsigned char *sha1)
 106 {
 107         if (this->nr_alloc <= this->nr_heads) {
 108                 this->nr_alloc = alloc_nr(this->nr_alloc);
 109                 this->head = xrealloc(this->head, this->nr_alloc * 20);
 110         }
 111         memcpy(this->head[this->nr_heads++], sha1, 20);
 112         return 0;
 113 }
 114
 115 /* Returns non-zero when we detect that the info in the
 116  * old file is useless.
 117  */
 118 static int parse_pack_def(const char *line, int old_cnt)
 119 {
 120         struct pack_info *i = find_pack_by_name(line + 2);
 121         if (i) {
 122                 i->old_num = old_cnt;
 123                 return 0;
 124         }
 125         else {
 126                 /* The file describes a pack that is no longer here;
 127                  * dependencies between packs needs to be recalculated.
 128                  */
 129                 return 1;
 130         }
 131 }
 132
 133 /* Returns non-zero when we detect that the info in the
 134  * old file is useless.
 135  */
 136 static int parse_depend_def(char *line)
 137 {
 138         unsigned long num;
 139         char *cp, *ep;
 140         struct pack_info *this, *that;
 141
 142         cp = line + 2;
 143         num = strtoul(cp, &ep, 10);
 144         if (ep == cp)
 145                 return error("invalid input %s", line);
 146         this = find_pack_by_old_num(num);
 147         if (!this)
 148                 return 0;
 149         while (ep && *(cp = ep)) {
 150                 num = strtoul(cp, &ep, 10);
 151                 if (ep == cp)
 152                         break;
 153                 that = find_pack_by_old_num(num);
 154                 if (!that)
 155                         /* The pack this one depends on does not
 156                          * exist; this should not happen because
 157                          * we write out the list of packs first and
 158                          * then dependency information, but it means
 159                          * the file is useless anyway.
 160                          */
 161                         return 1;
 162                 this->dep[that->new_num] = 1;
 163         }
 164         return 0;
 165 }
 166
 167 /* Returns non-zero when we detect that the info in the
 168  * old file is useless.
 169  */
 170 static int parse_head_def(char *line)
 171 {
 172         unsigned char sha1[20];
 173         unsigned long num;
 174         char *cp, *ep;
 175         struct pack_info *this;
 176         struct object *o;
 177
 178         cp = line + 2;
 179         num = strtoul(cp, &ep, 10);
 180         if (ep == cp || *ep++ != ' ')
 181                 return error("invalid input ix %s", line);
 182         this = find_pack_by_old_num(num);
 183         if (!this)
 184                 return 1; /* You know the drill. */
 185         if (get_sha1_hex(ep, sha1) || ep[40] != ' ')
 186                 return error("invalid input sha1 %s (%s)", line, ep);
 187         if ((o = parse_object_cheap(sha1)) == NULL)
 188                 return error("no such object: %s", line);
 189         return add_head_def(this, sha1);
 190 }
 191
 192 /* Returns non-zero when we detect that the info in the
 193  * old file is useless.
 194  */
 195 static int read_pack_info_file(const char *infofile)
 196 {
 197         FILE *fp;
 198         char line[1000];
 199         int old_cnt = 0;
 200
 201         fp = fopen(infofile, "r");
 202         if (!fp)
 203                 return 1; /* nonexisting is not an error. */
 204
 205         while (fgets(line, sizeof(line), fp)) {
 206                 int len = strlen(line);
 207                 if (line[len-1] == '\n')
 208                         line[len-1] = 0;
 209
 210                 switch (line[0]) {
 211                 case 'P': /* P name */
 212                         if (parse_pack_def(line, old_cnt++))
 213                                 goto out_stale;
 214                         break;
 215                 case 'D': /* D ix dep-ix1 dep-ix2... */
 216                         if (parse_depend_def(line))
 217                                 goto out_stale;
 218                         break;
 219                 case 'T': /* T ix sha1 type */
 220                         if (parse_head_def(line))
 221                                 goto out_stale;
 222                         break;
 223                 default:
 224                         error("unrecognized: %s", line);
 225                         break;
 226                 }
 227         }
 228         fclose(fp);
 229         return 0;
 230  out_stale:
 231         fclose(fp);
 232         return 1;
 233 }
 234
 235 /* We sort the packs according to the date of the latest commit.  That
 236  * in turn indicates how young the pack is, and in general we would
 237  * want to depend on younger packs.
 238  */
 239 static unsigned long get_latest_commit_date(struct packed_git *p)
 240 {
 241         unsigned char sha1[20];
 242         struct object *o;
 243         int num = num_packed_objects(p);
 244         int i;
 245         unsigned long latest = 0;
 246
 247         for (i = 0; i < num; i++) {
 248                 if (nth_packed_object_sha1(p, i, sha1))
 249                         die("corrupt pack file %s?", p->pack_name);
 250                 if ((o = parse_object_cheap(sha1)) == NULL)
 251                         die("cannot parse %s", sha1_to_hex(sha1));
 252                 if (o->type == commit_type) {
 253                         struct commit *commit = (struct commit *)o;
 254                         if (latest < commit->date)
 255                                 latest = commit->date;
 256                 }
 257         }
 258         return latest;
 259 }
 260
 261 static int compare_info(const void *a_, const void *b_)
 262 {
 263         struct pack_info * const* a = a_;
 264         struct pack_info * const* b = b_;
 265
 266         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 267                 /* Keep the order in the original */
 268                 return (*a)->old_num - (*b)->old_num;
 269         else if (0 <= (*a)->old_num)
 270                 /* Only A existed in the original so B is obviously newer */
 271                 return -1;
 272         else if (0 <= (*b)->old_num)
 273                 /* The other way around. */
 274                 return 1;
 275
 276         if ((*a)->latest < (*b)->latest)
 277                 return -1;
 278         else if ((*a)->latest == (*b)->latest)
 279                 return 0;
 280         else
 281                 return 1;
 282 }
 283
 284 static void init_pack_info(const char *infofile, int force)
 285 {
 286         struct packed_git *p;
 287         int stale;
 288         int i = 0;
 289         char *dep_temp;
 290
 291         objdir = get_object_directory();
 292         objdirlen = strlen(objdir);
 293
 294         prepare_packed_git();
 295         for (p = packed_git; p; p = p->next) {
 296                 /* we ignore things on alternate path since they are
 297                  * not available to the pullers in general.
 298                  */
 299                 if (strncmp(p->pack_name, objdir, objdirlen) ||
 300                     strncmp(p->pack_name + objdirlen, "/pack/", 6))
 301                         continue;
 302                 i++;
 303         }
 304         num_pack = i;
 305         info = xcalloc(num_pack, sizeof(struct pack_info *));
 306         for (i = 0, p = packed_git; p; p = p->next) {
 307                 if (strncmp(p->pack_name, objdir, objdirlen) ||
 308                     p->pack_name[objdirlen] != '/')
 309                         continue;
 310                 info[i] = xcalloc(1, sizeof(struct pack_info) + num_pack);
 311                 info[i]->p = p;
 312                 info[i]->old_num = -1;
 313                 i++;
 314         }
 315
 316         if (infofile && !force)
 317                 stale = read_pack_info_file(infofile);
 318         else
 319                 stale = 1;
 320
 321         for (i = 0; i < num_pack; i++) {
 322                 if (stale) {
 323                         info[i]->old_num = -1;
 324                         memset(info[i]->dep, 0, num_pack);
 325                         info[i]->nr_heads = 0;
 326                 }
 327                 if (info[i]->old_num < 0)
 328                         info[i]->latest = get_latest_commit_date(info[i]->p);
 329         }
 330
 331         qsort(info, num_pack, sizeof(info[0]), compare_info);
 332         for (i = 0; i < num_pack; i++)
 333                 info[i]->new_num = i;
 334
 335         /* we need to fix up the dependency information
 336          * for the old ones.
 337          */
 338         dep_temp = NULL;
 339         for (i = 0; i < num_pack; i++) {
 340                 int old;
 341
 342                 if (info[i]->old_num < 0)
 343                         continue;
 344                 if (! dep_temp)
 345                         dep_temp = xmalloc(num_pack);
 346                 memset(dep_temp, 0, num_pack);
 347                 for (old = 0; old < num_pack; old++) {
 348                         struct pack_info *base;
 349                         if (!info[i]->dep[old])
 350                                 continue;
 351                         base = find_pack_by_old_num(old);
 352                         if (!base)
 353                                 die("internal error renumbering");
 354                         dep_temp[base->new_num] = 1;
 355                 }
 356                 memcpy(info[i]->dep, dep_temp, num_pack);
 357         }
 358         free(dep_temp);
 359 }
 360
 361 static void write_pack_info_file(FILE *fp)
 362 {
 363         int i, j;
 364         for (i = 0; i < num_pack; i++)
 365                 fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6);
 366
 367         for (i = 0; i < num_pack; i++) {
 368                 fprintf(fp, "D %1d", i);
 369                 for (j = 0; j < num_pack; j++) {
 370                         if ((i == j) || !(info[i]->dep[j]))
 371                                 continue;
 372                         fprintf(fp, " %1d", j);
 373                 }
 374                 fputc('\n', fp);
 375         }
 376
 377         for (i = 0; i < num_pack; i++) {
 378                 struct pack_info *this = info[i];
 379                 for (j = 0; j < this->nr_heads; j++) {
 380                         struct object *o = lookup_object(this->head[j]);
 381                         fprintf(fp, "T %1d %s %s\n",
 382                                 i, sha1_to_hex(this->head[j]), o->type);
 383                 }
 384         }
 385
 386 }
 387
 388 #define REFERENCED 01
 389 #define INTERNAL  02
 390 #define EMITTED   04
 391
 392 static void show(struct object *o, int pack_ix)
 393 {
 394         /*
 395          * We are interested in objects that are not referenced,
 396          * and objects that are referenced but not internal.
 397          */
 398         if (o->flags & EMITTED)
 399                 return;
 400
 401         if (!(o->flags & REFERENCED))
 402                 add_head_def(info[pack_ix], o->sha1);
 403         else if ((o->flags & REFERENCED) && !(o->flags & INTERNAL)) {
 404                 int i;
 405
 406                 /* Which pack contains this object?  That is what
 407                  * pack_ix can depend on.  We earlier sorted info
 408                  * array from youngest to oldest, so try newer packs
 409                  * first to favor them here.
 410                  */
 411                 for (i = num_pack - 1; 0 <= i; i--) {
 412                         struct packed_git *p = info[i]->p;
 413                         struct pack_entry ent;
 414                         if (find_pack_entry_one(o->sha1, &ent, p)) {
 415                                 info[pack_ix]->dep[i] = 1;
 416                                 break;
 417                         }
 418                 }
 419         }
 420         o->flags |= EMITTED;
 421 }
 422
 423 static void find_pack_info_one(int pack_ix)
 424 {
 425         unsigned char sha1[20];
 426         struct object *o;
 427         struct object_list *ref;
 428         int i;
 429         struct packed_git *p = info[pack_ix]->p;
 430         int num = num_packed_objects(p);
 431
 432         /* Scan objects, clear flags from all the edge ones and
 433          * internal ones, possibly marked in the previous round.
 434          */
 435         for (i = 0; i < num; i++) {
 436                 if (nth_packed_object_sha1(p, i, sha1))
 437                         die("corrupt pack file %s?", p->pack_name);
 438                 if ((o = lookup_object(sha1)) == NULL)
 439                         die("cannot parse %s", sha1_to_hex(sha1));
 440                 for (ref = o->refs; ref; ref = ref->next)
 441                         ref->item->flags = 0;
 442                 o->flags = 0;
 443         }
 444
 445         /* Mark all the internal ones */
 446         for (i = 0; i < num; i++) {
 447                 if (nth_packed_object_sha1(p, i, sha1))
 448                         die("corrupt pack file %s?", p->pack_name);
 449                 if ((o = lookup_object(sha1)) == NULL)
 450                         die("cannot find %s", sha1_to_hex(sha1));
 451                 for (ref = o->refs; ref; ref = ref->next)
 452                         ref->item->flags |= REFERENCED;
 453                 o->flags |= INTERNAL;
 454         }
 455
 456         for (i = 0; i < num; i++) {
 457                 if (nth_packed_object_sha1(p, i, sha1))
 458                         die("corrupt pack file %s?", p->pack_name);
 459                 if ((o = lookup_object(sha1)) == NULL)
 460                         die("cannot find %s", sha1_to_hex(sha1));
 461
 462                 show(o, pack_ix);
 463                 for (ref = o->refs; ref; ref = ref->next)
 464                         show(ref->item, pack_ix);
 465         }
 466
 467 }
 468
 469 static void find_pack_info(void)
 470 {
 471         int i;
 472         for (i = 0; i < num_pack; i++) {
 473                 /* The packed objects are cast in stone, and a head
 474                  * in a pack will stay as head, so is the set of missing
 475                  * objects.  If the repo has been reorganized and we
 476                  * are missing some packs available back then, we have
 477                  * already discarded the info read from the file, so
 478                  * we will find (old_num < 0) in that case.
 479                  */
 480                 if (0 <= info[i]->old_num)
 481                         continue;
 482                 find_pack_info_one(i);
 483         }
 484 }
 485
 486 static int update_info_packs(int force)
 487 {
 488         char infofile[PATH_MAX];
 489         char name[PATH_MAX];
 490         int namelen;
 491         FILE *fp;
 492
 493         namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
 494         strcpy(name, infofile);
 495         strcpy(name + namelen, "+");
 496
 497         init_pack_info(infofile, force);
 498         find_pack_info();
 499
 500         safe_create_leading_directories(name);
 501         fp = fopen(name, "w");
 502         if (!fp)
 503                 return error("cannot open %s", name);
 504         write_pack_info_file(fp);
 505         fclose(fp);
 506         rename(name, infofile);
 507         return 0;
 508 }
 509
 510 /* public */
 511 int update_server_info(int force)
 512 {
 513         /* We would add more dumb-server support files later,
 514          * including index of available pack files and their
 515          * intended audiences.
 516          */
 517         int errs = 0;
 518
 519         errs = errs | update_info_refs(force);
 520         errs = errs | update_info_packs(force);
 521
 522         return errs;
 523 }